1 Journal of Herpetology, Vol. 39, No. 4, pp , 2005 Copyright 2005 Society for the Study of Amphibians and Reptiles The Efficacy of Visual Encounter Surveys for Population Monitoring of Plethodon punctatus (Caudata: Plethodontidae) WILLIAM D. FLINT AND REID N. HARRIS 1 Department of Biology, MSC 7801, James Madison University, Harrisonburg, Virginia 22807, USA ABSTRACT. Effective monitoring of population size is critically important for endemic species with specialized habitat requirements so that timely remedial steps can be taken when declines are detected. We initiated a monitoring study of the endemic plethodontid salamander, Plethodon punctatus, which is generally found in talus habitats over 1000 m in elevation in a narrow range on Shenandoah Mountain on the border of Virginia and West Virginia. We tested congruence of nighttime visual encounter surveys (VES) and markrecapture estimates of population size. VES was a valid index of the abundances of P. punctatus in the two habitats we surveyed. Sites on the eastern and western sides of Shenandoah Mountain were surveyed, and both methods estimated that population size on the west was approximately twice as high as that on the east. Individuals of this species exhibited a high degree of site fidelity. Cover object searches for species in talus habitats are expected to be of limited value, and we conclude that nighttime visual encounter surveys are most effective for population size monitoring of P. punctatus and other species that live in talus. Monitoring amphibian species is becoming increasingly important because many populations are declining (Alford and Richards, 1999; Stuart et al., 2004). Among the 56 terrestrial salamander species in the United States with direct development, too little is known about 24 of them (43%) to determine their conservation status (Wyman, 2003). Terrestrial salamanders are considered indicators of environmental health (Welsh and Droege, 2001) and may be sensitive to environmental disturbances. Corser (2001) found that disjunct populations of the terrestrial Green Salamander, Aneides aeneus, had declined 98% in abundance since the 1970s. Richard Highton (unpubl. data) found little difference in the abundance of 38 species of Plethodon between the 1950s and the 1980s but found a decrease when comparing abundances of all previous years to the 1990s. These studies suggest that there may be a recent trend toward population declines among plethodontid salamanders. Woodland salamanders in the genus Plethodon are a diverse group often found at high population densities, and they comprise an important component of terrestrial food webs (Jaeger, 1980; Hairston, 1987). Currently there are 45 recognized species of Plethodon in the Eastern United States alone (Highton, 1995, 1999). Many of these species have a limited range or specific habitat requirements and are sensitive to anthropomorphic disturbances. The Cow Knob Salamander, Plethodon punctatus, is an endemic species of woodland salamander that is patchily 1 Corresponding Author. distributed within a narrow range on Shenandoah Mountain on the Virginia/West Virginia state border (Highton, 1972). Its habitat consists of talus areas above 1000 m (Buhlmann et al., 1988; T. K. Pauley, Surveys for Plethodon punctatus in the George Washington National Forest, WV, USDA Forest Service, 1995). Because the rarity of this species was realized after some preliminary studies (Highton, 1972; Fraser, 1976; Buhlmann et al., 1988), P. punctatus was recognized as a species of special concern by the Virginia Department of Game and Inland Fisheries and by the West Virginia Division of Natural Resources. When monitoring cryptic, sensitive, and rare species, such as many members of the genus Plethodon, it is important to use methods that yield accurate estimates of population density and provide minimal disturbance to critical habitats. Daytime cover object surveys have historically been the primary method for monitoring terrestrial salamanders but are expected to be of limited use in assessing abundances of species that live in talus and are likely to disturb the habitat. Nighttime visual encounter surveys (VES), which involve counting the number of individuals present in a given survey area or over a specific time period, have the potential to overcome both of these limitations. Visual encounter surveys can be more efficient in terms of time and money but need to be compared with a study that estimates population size using mark-recapture or removal methods (Crump and Scott, 1994). If VES is a representative index of relative population density among sites within years or within sites among years, then it can be used effectively as a monitoring technique. The
2 ECOLOGY OF PLETHODON PUNCTATUS 579 goals of this study were to evaluate the efficacy of VES in determining relative abundances of P. punctatus in two different habitats, evaluate conditions that influence the abundance and activity of P. punctatus, examine patterns in the size distribution and body condition of individuals in the study populations, and provide the basis for a long-term monitoring study. MATERIALS AND METHODS Population monitoring stations were established at two sites with known populations of P. punctatus in We set up one site on the east side of Shenandoah Mountain in Virginia and one site on the west side of Shenandoah Mountain in West Virginia to investigate whether populations on the west side of the mountain had higher densities as has been previously suggested (Tucker, 1998; J. C. Mitchell, Distribution of the Cow Knob Salamander [Plethodon punctatus] on Shenandoah Mountain, George Washington-Jefferson National Forest: report for the 1996 field season, 1996). Higher salamander densities on the west side of Shenandoah Mountain had been attributed to an assumed higher average rainfall on that side of the mountain (Buhlmann et al., 1988; Tucker, 1998). The Virginia site, hereafter referred to as Tomahawk, was located in Rockingham County, on Tomahawk Mountain south of Forest Service Road 72. The West Virginia site, hereafter referred to as Sugar Grove, was located in Pendleton County just north of Reddish Knob south of West Virginia Route 25. Both sites had a similar elevation (1100 m), a north-facing aspect, and were in talus habitat. At each site, a m quadrat (225 m 2 ) was delineated, which was further divided into 535 m grids. Survey quadrats of these dimensions were chosen for consistency with previous studies on Plethodon (Fraser, 1976; Marvin 1996) and were recommended by Crump and Scott (1994). These sites were monitored for one year with Visual Encounter Surveys (VES) and markrecapture surveys, which were conducted within quadrats at night during or within hours after rain events when salamanders were present at the surface (Hairston, 1980; Crump and Scott, 1994). Initial surveys during dry conditions indicated that salamanders were not present on the surface; hence, surveys were restricted to wet conditions. Each site was surveyed twice each month by carefully walking all of the grids within each quadrat for the entire portion of the year that nighttime low temperatures were consistently above 08C. Air temperature, soil temperature, and humidity were measured using a Reotemp Ò thermometer and dial hygrometer at each study site. Rocks and cover objects were not overturned nor was the habitat in any way altered from its natural state. Upon capture, each salamander was placed in a cm plastic container labeled with an identification number, its location was noted with a flag; and the flag was left until the survey was completed. The location of each salamander within the quadrat was also mapped on a data sheet containing a schematic of the quadrat. Each individual was weighed with a Pesola Ò spring balance, measured with a ruler, and photographed with a digital camera. Individuals were kept still for measurement and photography using a device designed by Wise and Buchanan (1992). Upon the completion of this process each salamander was released at its point of capture. After subsequent surveys, photographs were compared, recaptured individuals were identified, and the distance traveled between captures was measured. Population size at each site was estimated using the Schumacher-Eschmeyer method, which is similar to but considered to be more robust and powerful than the Schnabel method (Krebs, 1998:37) and is used for estimating closed populations when mark-recapture samples are taken on three or more occasions. Population size is estimated using the same approach as the Peterson method but is modified for multiple captures. This method assumes (1) population size is constant without recruitment or losses; (2) sampling is random; and (3) all individuals have an equal chance of being caught. Support for using the Schumacher-Eschmeyer method comes from our findings that populations of P. punctatus move very little throughout the year and can be considered for these purposes to represent closed populations (see below). Other studies on other Woodland Salamanders have concluded that populations are closed during a year (Marvin, 2001; Petranka and Murray, 2001). We defined overall detection probability as the mean number of salamanders observed divided by the markrecapture estimate of population size, sample detection probability as the number of salamanders observed on a particular date divided by the mark-recapture estimate of population size, and recapture probability as the total number of recaptured individuals divided by the total number of individuals captured (Smith and Petranka, 2000). Our survey on 30 August revealed a qualitatively different situation than on all other surveys. Population densities and distances traveled were much higher than on all other dates, and courtship activity (tail straddle walk) was observed. After this date, recaptured individuals returned to their home ranges and moved little. To avoid potentially confounding effects of courtship activities and to satisfy assumptions of the mark-recapture method, we excluded 30 August sample from all analyses.
3 580 W. D. FLINT AND R. N. HARRIS FIG. 1. Estimated population size of Plethodon punctatus at Tomahawk and Sugar Grove monitoring stations. We were able to compare body conditions of the two study populations using ANCOVA. We created an index of body condition by regressing log-transformed mass on log-transformed SVL. Our parametric correlation coefficients were essentially 1.0; thus, we used a least-squares regression (Green, 2001). We analyzed the correlation between temperature and abundance with a parametric Pearson correlation. We acquired rainfall data from the two closest sites (mean distance 5 12 km) on the west side from the crest of Shenandoah Mountain in West Virginia and three closest sites (mean distance 5 24 km) on the east side of Shenandoah Mountain in Virginia from the National Climatic Data Center and the Spatial Climate Analysis Service. A t-test was used to test for differences in mean rainfall between sites. RESULTS For the entire active season (April through October) of P. punctatus, at both monitoring stations, we observed 311 individuals. At Sugar Grove, we observed 223 individuals of which 132 were captured once, 64 were captured more than once, and 27 escaped. At Tomahawk Mountain, we observed 88 individuals of which 53 were captured once, 27 were captured more than once, and eight escaped. Population size differed between sites. The Schumacher-Eschmeyer mark-recapture method indicated that there was a significant difference (P, 0.05) between the population sizes at Tomahawk (81.93; lower 95% confidence interval [CI] ; upper 95% CI ) and Sugar Grove (149.79; lower 95% CI ; upper 95% CI ; Fig. 1). The estimated population density at Tomahawk was 0.36 individuals/m 2 ; the estimated density at Sugar Grove was 0.67 individuals/m 2. Our VES also estimated more salamanders at Sugar Grove monitoring station than Tomahawk monitoring FIG. 2. Mean monthly number of salamanders observed per 225 m 2 quadrat at Sugar Grove and Tomahawk Mountain monitoring stations. station, with an equivalent search effort at both sites (Fig. 2). At Sugar Grove, we observed an average of P. punctatus per night with a 95% CI of At Tomahawk, we observed an average of 6.77 P. punctatus per night with a 95% CI of These CIs are based on potentially autocorrelated data; thus, are not intended for hypothesis testing. We are confident in our population size estimates because of our high probability of recapturing an individual salamander and confident of our population size comparison because of similar detection and recapture probabilities at both sites (average detection probabilities were and and recapture probabilities were and at Sugar Grove and Tomahawk, respectively). Peak summer numbers in June, July, and August were approximately twice as high at Sugar Grove than at Tomahawk (Fig. 2). Thus, the VES method was an index of relative population size at the two sites. Similar seasonal activity patterns were observed at both sites (Fig. 2). We first observed P. punctatus on 13 April at Sugar Grove monitoring station and on 7 May at Tomahawk monitoring station. Plethodon punctatus was most active during the warmest parts of the summer. At Sugar Grove, we found that P. punctatus densities were more strongly correlated with soil temperature (r , df 5 13, P, ) than air temperature (r , df 5 13, P, ). A similar pattern was observed at Tomahawk. Plethodon punctatus was last observed 8 October at Sugar Grove and 4 October at Tomahawk Mountain. We observed very different size class distributions at Tomahawk Mountain than at Sugar Grove (Fig. 3). At the Sugar Grove monitoring station 47% of the captures were larger than 49 mm SVL for males and 59 mm SVL for females, strongly suggesting that they were adults (Tucker, 1998), and all size classes were well represented (Fig. 3). At Tomahawk Mountain,
4 ECOLOGY OF PLETHODON PUNCTATUS 581 FIG. 3. Size class distribution of salamanders observed at Tomahawk and Sugar Grove monitoring stations. however, adults made up only 17.5% of the captured population, whereas juveniles made up 82.5%. ANCOVA comparing body condition index scores from the two sites indicated that individuals of P. punctatus at Sugar Grove had higher condition index scores than individuals from Tomahawk (F 1, , P ). In fact, the regression line for Sugar Grove was consistently above the regression line for Tomahawk over the range of SVLs measured. The slope of the two lines was significantly different (F 1, , P ), which can be attributed to juveniles at Tomahawk being in worse condition than juveniles at Sugar Grove, whereas condition index scores of the two populations tended to converge with individuals with the highest SVLs. We analyzed the distance moved from the point of initial capture to subsequent recaptures and found that P. punctatus had very high site fidelity. At Sugar Grove, adult salamanders moved an average of 1.96 m from their initial point of capture to recapture locations, whereas juveniles moved an average of 1.27 m. For both adults (r , df 5 31, P ) and juveniles (r , df 5 16, P ), number of days between initial capture and recapture had no effect on distance moved from initial capture site. Similarly, at Tomahawk we found that salamanders moved an average of 1.94 m from the point of initial capture to recapture locations. Number of days elapsed between initial capture and recapture had no effect on distance moved (r , df 5 25, P ). There were too few adult recaptures at Tomahawk (N 5 3) to analyze movement for adults and juveniles separately. We found that there was no difference in annual rainfall between stations on the east and west sides of Shenandoah Mountain (89.48 cm SE and cm SE, respectively; t , P ). DISCUSSION Our study provides baseline data for long-term monitoring of P. punctatus on Shenandoah Mountain and suggests that this species was approximately twice as abundant at a site on the western side of Shenandoah Mountain than at a site on the eastern side. This conclusion is based on both VES and mark-recapture methods. This congruence of VES and mark-recapture methods suggests that VES is a valid index of population size for this species. An assessment of the congruence of VES and mark-recapture methods has been urged by Crump and Scott (1994) as part of any amphibian species monitoring plan. VES is less labor intensive, and we recommend it for accurate population monitoring of P. punctatus. The differences in population density between east and west sides of the mountain may be caused by to habitat and moisture differences. Both the Tomahawk and Sugar Grove monitoring stations have a similar elevation and northfacing aspect. However, Sugar Grove is located 160 m lower than the crest in a cove, whereas Tomahawk is just below the crest. In addition, the Tomahawk monitoring station has patches of talus and deeper soil, whereas the Sugar Grove monitoring station is almost completely talus, which is the preferred habitat type (Buhlmann et al., 1988). Finally, we found that there was no difference in rainfall between the two sides of the mountain. However, we observed that the west side of the mountain appeared to be wetter than is the east side, supporting greater communities of mosses and ferns. We hypothesize that this is a result of moisture deposited through mist and cloud water on the west side of Shenandoah Mountain (Pounds et al., 1999). In addition, mean body condition was greater at Sugar Grove than it was at Tomahawk. The drier conditions at Tomahawk may result in fewer suitable nights during which salamanders can feed at the surface and lead to poorer salamander condition. We estimated similar average detection probabilities over the course of the study at Sugar Grove and Tomahawk. This result suggests that our protocol of sampling during optimal moist conditions was effective in equalizing detection probabilities at both sites. Sample detection probability varies directly with VES count. We detected seasonal differences in detection probability at both sites (Fig. 2) and a relationship between detection probability and soil temperature (Bailey et al., 2004). To maximize detection probability for this species, counts should be made during the summer months on moist nights. Tomahawk and Sugar Grove had different size-frequency distributions. At Tomahawk, the majority of captures were juveniles, suggesting
5 582 W. D. FLINT AND R. N. HARRIS a recent catastrophic loss of adults. However, at Sugar Grove, we found that all size classes were well represented and juveniles only made up about half of the total population. For two years preceding our study (2001 and 2002), the southeastern United States experienced drought conditions. Populations of P. punctatus on the relatively unfavorable east side of the mountain may have been differentially affected by the drought, leading to a decline in that population. Seasonal activity and site fidelity were similar at both sites. At both sites, peak activity occurred in the three summer months (June through August). The similar activity patterns are likely a result of each population responding the same way to similar temperature regimes. Our information has proven useful to USDA Forest Service officials because they determine the optimal time for controlled burning. Territory use by Woodland Salamanders has been well documented (Jaeger et al., 1982; Mathis, 1991; Lang and Jaeger, 2000). Site fidelity in P. punctatus is suggested by the observation that distance moved from the site of original capture was small and that distance moved did not vary with time between captures. Whether individuals of P. punctatus aggressively defend an area is the subject of future work. Several previous studies have surveyed P. punctatus. Tucker (1998) performed primarily daytime cover object searches and found P. punctatus to be most active in June and least active in August. Buhlmann et al. (1988) also performed primarily daytime cover object searches and similarly found P. punctatus to be most active in late May and least active in late July and August. Fraser (1976) performed both daytime cover object searches and nighttime visual area surveys and found highest densities of P. punctatus in June and lowest densities in late August and September. Traditionally, observers have interpreted this seasonal activity pattern by stating that P. punctatus are not active during mid to late summer because of the hot and dry conditions. However, our observations suggest that individuals of P. punctatus were not active at the surface during any dry period, warm or cold. By searching for P. punctatus after rain events at night, we found the greatest densities of P. punctatus during the warmest nights surveyed (June through August). We conclude that P. punctatus are no less active during the hottest periods of summer; they are just more difficult to locate at the surface during the day. The seasonal activity patterns found in previous studies may be an artifact of using daytime cover object searches. We hypothesize that daytime cover object searches greatly underestimate the density or even the presence of P. punctatus. This species occurs in highest densities in pure talus habitats. Talus is composed of rock on top of rock, often down to bedrock, with very little soil present. Because there are air spaces between these rocks and little soil, the surface of the talus will be drier during the day than would a rock sitting on top of deeper soil. Therefore, although P. punctatus densities are greatest in pure talus, they are hardest to find during the day in these habitats because during these times they retreat well below the surface. We have found that following rain events during the day, it is possible to find P. punctatus under rocks on top of soil at the periphery of an area of talus but very difficult to find the species within the talus itself. However, in the same areas of talus that were searched unsuccessfully during the day, P. punctatus will be present and often abundant at night. Although it has been demonstrated that daytime cover object surveys are correlated with mark-recapture estimates (Smith and Petranka, 2000) for terrestrial species that live on deep soil substrates, our data suggest that it may be unlikely that such a correlation will be found for species that live on talus substrates. The addition of artificial cover boards may also be problematic in talus habitats because there is little or no soil in which to seat the boards. The hypothesis that daytime cover object searches underestimate population densities of P. punctatus is suggested by a comparison of this study with Tucker (1998), who executed a markrecapture survey using daytime cover object searches within 200 m from our Sugar Grove monitoring station. He estimated a population density of P. punctatus/m 2 based on 13 marked and two recovered salamanders. At Sugar Grove, we estimated a population density of 0.67/m 2 based on 196 marked and 64 recovered salamanders. It is possible that this 10-fold difference is a result of variation in population density among years, however it is also possible that the use of cover object searches, with or without a mark-recapture estimate, in a talus habitat is less effective than nighttime visual encounter surveys. We conclude that nighttime surveys are preferred over cover object searches for estimating presence, abundance, and life-stage composition of P. punctatus, and potentially other species that specialize in talus and/or subterranean habitats, such as Plethodon shenandoah, Plethodon petraeus, and Plethodon elongatus (Jaeger, 1970; Diller and Wallace, 1994; Welsh and Lind, 1995; Jensen et al., 2002). VES proved to be an adequate index of population size and would require less time and money than a mark-recapture study. Therefore, we recommend VES for monitoring of P. punctatus. In addition, the VES method does not alter or disturb the habitat in any way, which is important when multiple surveys will be employed
6 ECOLOGY OF PLETHODON PUNCTATUS 583 and when trying to minimize habitat disturbance for rare species (Hairston, 1980). Further study of the efficacy of VES in other species will help toward the goal of effectively and rapidly monitoring population trends of terrestrial plethodontids. Acknowledgments. We thank T. Slater for giving us permission to work in the George Washington National Forest and for providing data and logistical support. J. Wykle provided important background data and assisted in surveys. A special thanks to K. Burke, who helped with most of the field surveys, and to R. Highton, who shared unpublished data with us. M. Hudy, G. Wyngaard, and J. Kastendiek provided helpful comments on the manuscript. We had permission to capture salamanders from the Virginia Department of Game and Inland Fisheries and from the West Virginia Division of Natural Resources. Funding was provided by the USDA Forest Service, West Virginia Division of Natural Resources, and by a contract with R. Jung (USGS). LITERATURE CITED ALFORD, R. A., AND S. J. RICHARDS Global amphibian declines: a problem in applied ecology. Annual Review of Ecology and Systematics 30: BAILEY, L. L., T. R. SIMONS, AND K. H. POLLOCK Spatial and temporal variation in detection probability of plethodon salamanders using the robust capture-recapture design. Journal of Wildlife Management 68: BUHLMANN, K. A., C. A. PAGUE, J.C.MITCHELL, AND R. B. GLASGOW Forestry Operations and Terrestrial Salamanders: Techniques in the Study of the Cow Knob Salamander, Plethodon punctatus. Symposium, Management of Amphibians, Reptiles, and small Mammals in North America. July 19 21, 1988, Flagstaff, AZ. CORSER, J. D Decline of disjunct Green Salamander (Aneides aeneus) populations in the southern Appalachians. Biological Conservation 97: CRUMP, M. L., AND N. J. SCOTT JR Visual encounter surveys. In W. R. Heyer, M. A. Donnelly, R. W. McDiarmid, L. C. Hayek, and M. S. Foster (eds.), Measuring and Monitoring Biological Diversity: Standard Methods for Amphibians, pp Smithsonian Institution Press, Washington, DC. DILLER,L.V.,AND R. L. WALLACE Distribution and habitat of Plethodon elongatus on managed, young growth forests in north coastal California. Journal of Herpetology 28: FRASER, D. F Coexistance of salamanders in the genus Plethodon: a variation of the Santa Rosalia theme. Ecology 57: GREEN, A. J Mass/length residuals: measures of body condition or generators of spurious results? Ecology 82: HAIRSTON, N. G The experimental test of an analysis of field distributions: competition in terrestrial salamanders. Ecology 61: Community Ecology and Salamander Guilds. Cambridge Univ. Press, Cambridge. HIGHTON, R Distributional interactions among Eastern North American salamanders of the genus Plethodon. In C. Holt (ed.), The Distributional History of the Biota of the Southern Appalachians. Part III. Vertebrates, pp Research Division Monograph, Virginia Polytechnic Institute and State Univ., Blacksburg Speciation in Eastern North American salamanders of the genus Plethodon. Annual Review of Ecology and Systematics 26: Geographic protein variation and speciation in the salamanders of the Plethodon cinereus group with the description of two new species. Herpetologica 55: JAEGER, R. G Potential extinction through competition between two species of salamanders. Evolution 24: Microhabitats of a terrestrial forest salamander. Copeia 1980: JAEGER, R. G., D. KALVARSKY, AND N. SHIMIZU Territorial behavior of the Red-Backed Salamander Plethodon cinereus expulsion of intruders. Animal Behaviour 30: JENSEN, J. B., C. D. CAMP, AND J. L. MARSHALL Ecology and life history of the Pigeon Mountain Salamander. Southeast Naturalist 1:3 16. KREBS, C. J Ecological Methodology. 2nd ed., Addison-Welsey Educational Publishers, Inc., Menlo Park, CA. LANG, C., AND R. G. JAEGER Defense of territories by male-female pairs in the Red-Backed Salamander (Plethodon cinereus). Copeia 2000: MARVIN, G. A Life history and population characteristics of the salamander Plethodon kentucki with a review of Plethodon life histories. American Midland Naturalist 136: Age, growth, and long-term site fidelity in the terrestrial plethodontid salamander, Plethodon kentucki. Copeia 2001: MATHIS, A Territories of male and female terrestrial salamanders: costs, benefits, and intersexual spatial associations. Oecologia 86: PETRANKA, J. W., AND S. S. MURRAY Effectiveness of removal sampling for determining salamander density and biomass: a case study in an Appalachian streamside community. Journal of Herpetology 35: POUNDS, J. A., M. P. FOGDEN, AND J. H. CAMPBELL Biological response to climate change on a tropical mountain. Nature 398: SMITH, C. K., AND J. W. PETRANKA Monitoring terrestrial salamanders: repeatability and validity of area-constrained cover object searches. 34: STUART, S. N., J. S. CHANSON, N. A. COX, B. E. YOUNG, A. S. L. RODRIGUES, D. L. FISCHMAN, AND R. W. WALLER Status and trends of amphibian declines and extinctions worldwide. Science 306: TUCKER, R. B Ecology and Natural History of the Cow Knob Salamander, Plethodon punctatus Highton, in West Virginia. Unpubl. master s thesis, Marshall Univ., Huntington, WV.
7 584 W. D. FLINT AND R. N. HARRIS WELSH, H. H., AND S. DROEGE A case for using plethodontid salamanders for monitoring biodiversity and ecosystem integrity of North American forests. Conservation Biology 15: WELSH, H. H., AND A. L. LIND Habitat correlates of the Del Norte Salamander Plethodon elongatus (Caudata: Plethodontidae), in northwestern California. Journal of Herpetology 29: WISE, S. E., AND B. W. BUCHANAN An efficient method for measuring salamanders. Herpetological Review 23: WYMAN, R. L Conservation of terrestrial salamanders with direct development. In R. D. Semlitsch (ed.), Amphibian Conservation, pp Smithsonian Books, Washington, DC. Accepted: 11 August Journal of Herpetology, Vol. 39, No. 4, pp , 2005 Copyright 2005 Society for the Study of Amphibians and Reptiles New Species of Cyrtodactylus (Squamata: Gekkonidae) from Southern Peninsular Malaysia L. LEE GRISMER 1,2 AND TZI MING LEONG 3 1 Department of Biology, 4500 Riverwalk Parkway La Sierra University, Riverside, California , USA; 3 Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore ABSTRACT. A new species of Cyrtodactylus is described from lowland forest of southern Peninsular Malaysia. It differs from all other Cyrtodactylus by having a unique suite of characteristics involving coloration and scalation. This is the third species of amphiban or reptile restricted to the southern portion of the Malay Peninsula. Cyrtodactylus is one of the most speciose gekkonid genera (Kluge, 2001) with descriptions of new species occurring at an ever-increasing rate (Bauer, 2002, 2003; Bauer et al., 2002, 2003; Grismer, 2005; Youmans and Grismer, 2005). Cyrtodactylus ranges from tropical South Asia through much of Indochina, the Philippines, and the Indo-Australian Archipelago as far east as the Solomon Islands (Bauer and Henle, 1994). There are at least 20 species currently recognized from the Sunda Shelf (Manthey and Grossman, 1997; Grismer, 2005; Youmans and Grismer, 2005), and in Peninsular Malaysia, eight species are known to occur. Although various localities within Peninsular Malaysia have been reasonably well surveyed (i.e., Ulu Gombak, Selangor; Bukit Larut, Perak; Bukit Frazier, Gunung Benom, and Genting Highlands, Pahang; and the Temengor Forest Reserve and adjacent regions, and Perak to name a few) there still remain large tracts of primary forest for which our herpetological knowledge is based solely on a few random, unpublished collections. In southern Malaysia, these principle areas are the mountainous regions and surrounding lowlands of the southern state of Johor, 2 Corresponding Author. namely the montane system that encompasses the Endau-Rompin Forest Reserve (which extends northward into the southern portion of the state of Pahang) and a series of peaks to the south which extend from Gunung Berlumut in central Johor, southward to Gunung Panti just north of the city of Kota Tinggi. During a brief collecting period on 6 July 2001, approximately 10 km west of Jemaluang, we collected two specimens of an unidentified species of Cyrtodactylus. Additional specimens were subsequently collected near the base of Gunung Panti, 50 km to the south. MATERIALS AND METHODS Measurements follow Grismer (2005) and were taken with Mitutoyo digital calipers to the nearest 0.1 mm: snout-vent length (SVL), from tip of snout to vent; trunk length (TrunkL), from posterior margin of forelimb insertion to anterior margin of hind limb insertion; crus length (CrusL), from base of heel to knee; tail length (TailL), from vent to tip of original tail; tail width (TailW), measured at widest part of tail; head length (HeadL), measured from retroarticular process of jaw to tip of snout; head width (HeadW), measured at widest part of head; head height (HeadH), measured from occiput to underside of lower jaws; ear length (EarL), taken
8 NEW MALAYSIAN CYRTODACTYLUS 585 FIG. 1. Type series of Cyrtodactylus semenanjungensis. Left to right: Holotype ZRC , , , and as longest dimension of ear; forearm length (ForeaL), from base of palm to elbow; orbit diameter (OrbD), measured as greatest diameter of orbit; nares to eye distance (NarEye), distance between anteriormost part of eye and nares; snout to eye distance (SnEye), measured from anteriormost point of eye to tip of snout; eye to ear distance (EyeEar), from anterior edge of ear opening to posterior edge of eye; internarial distance (Internar), taken between nares; and interorbital distance (Interorb), measured as shortest distance between left and right superciliary scale rows. Scale counts taken were postmentals (and their degree of medial contact); supralabials, counted to midpoint of eye; infralabials; scales bordering nostril (number and types); number of longitudinal rows of tubercles counted from one side of body across dorsum to other side; number of paravertebral tubercles counted along right side of vertebral axis from midpoint of fore- and hindlimb insertions; number of ventral scales counted between dorsolateral body folds; and number of subdigital lamellae on the fourth toe. Color pattern characteristics used include the presence or absence of a lightly colored reticulate pattern on the top of the head; the degree of banding in adults; and the number of bands between the limb insertions. Many species have distinctly banded juveniles whose pattern becomes obscured by blotching at adulthood. Others, however, maintain an essentially banded pattern throughout life. Counts and measurements were made on the right side of the body with a Wild M 10 dissecting microscope. Preserved material examined is listed below (Appendix 1). Characters were also taken from Das and Lim (2000), De Rooij (1915), Dring (1979), Hikida (1990), Inger and King (1961), Manthey and Grossman (1997), Pauwels et al. (2004), Smith (1930), and Taylor (1963). Cyrtodactylus semenanjungensis sp. nov. Figures 1,2 Holotype. Adult male (ZRC ) collected on 17 January 2004 on Panti Bunker Trail, Kota Tinggi, Johor, West Malaysia. Paratypes. ZRC (juvenile) collected from same locality as holotype and ZRC (adult male) and ZRC (adult female) collected on 6 July 2001 from 10 km west of Jemaluang, Johor, West Malaysia. Diagnosis. Distinguished from all other Sunda Shelf species by having the following suite of character states: mm SVL; moderately
9 586 L. L. GRISMER AND T. M. LEONG FIG. 2. Preanal region of holotype, ZRC sized, conical, keeled body tubercles; tubercles on forelimbs and beyond base of tail; ventral scales across belly; no transversely enlarged, median subcaudal scales; proximal subdigital lamellae transversely expanded; abrupt transition between posterior and ventral femoral scales; no enlarged femoral scales or pores; presence of a preanal groove; enlarged preanal scales; no preanal pores; distinctive, bold, dark brown transverse body bands with little to no ontogenetic change. Description of Holotype. Adult male SVL 62.1 mm; head moderately long (HeadL/SVL 0.26) and wide (HeadW/HeadL 0.66), somewhat depressed (HeadH/HeadL 0.44), distinct from neck, and triangular in dorsal profile; lores weakly inflated, prefrontal region concave, canthus rostralis smoothly rounded; snout elongate (SnEye/HeadL 0.43) and sharply rounded in dorsal profile; eye large (OrbD/HeadL 0.25); ear opening elliptical, small (EarL/HeadL 0.08); eye to ear distance grater than diameter of eye; rostral twice as wide as high, partially divided dorsally, bordered posteriorly by large left and right supranasals and medial postrostral (5 internasal); external nares bordered anteriorly by rostral, dorsally by a large anterior supranasal and small posterior supranasal, posteriorly by two postnasals and ventrally by first supralabial; 11 (R, L) square supralabial scales extending to below and tapering abruptly at the midpoint of eye, second supralabial largest; 10 (R) 9 (L) infralabial scales tapering smoothly posteriorly to posterior margin of orbit; scales of rostrum, lores, top of head, and occiput small and granular; scales of occiput intermixed with slightly enlarged tubercles; dorsal and ventral superciliaries cone-shaped and bluntly rounded; mental triangular, bordered laterally by first infralabial and posteriorly by left and right square postmentals which contact medially for 50% of their length posterior to mental; one slightly enlarged and elongate row of sublabials extending posteriorly to 6th infralabial; gular scales small and granular grading posteriorly into slightly larger, flatter, throat scales which grade into large, flat, imbricate pectoral and ventral scales. Body relatively short (TrunkL/SVL 0.44) with well-defined ventrolateral folds; dorsal scales small and granular interspersed with moderately sized, conical, semiregularly arranged, keeled tubercles; tubercles extend from occiput to anterior one-third of tail; tubercles on occiput and nape relatively small, those on body largest; approximately 18 longitudinal rows of tubercles and 32 paravertebral tubercles; 51 flat, imbricate ventral scales between ventrolateral body folds, ventral scales much larger than dorsal scales; two enlarged rows of preanal scales bordering opposite sides of a preanal groove; no preanal pores (Fig. 2). Forelimbs moderate in stature, relatively short (ForeL/SVL 0.16); granular scales of forearm slightly larger than those of body and interspersed with small tubercles; palmar scales rounded; digits well-developed, inflected at basal interphalangeal joints; subdigital lamellae transversely expanded proximal to joint inflections, digits narrow distal to joints; claws welldeveloped, sheathed by a dorsal and ventral scale. Hind limbs more robust than forelimbs, moderate in length (CrusL/SVL 0.18), covered dorsally by granular scales interspersed with larger tubercles and anteriorly by flat, slightly larger scales; ventral scales of femora flat and larger than dorsals; ventral tibial scales flat and imbricate; no enlarged femoral scales or femoral pores; dorsal and ventral femoral scales meet abruptly on posteroventral margin of thigh; plantar scales low and slightly rounded; digits well-developed, inflected at basal interphalangeal joints; subdigital lamellae transversely expanded proximal to inflected joints, digits narrow distal to joints; seven expanded subdigital lamellae and 11 nonexpanded subdigital lamellae on right 4th toe; claws well-developed, sheathed by a dorsal and ventral scale. Tail 68 mm in length, distal two-thirds regenerated, 5.2 mm in width at base, tapering to a point; dorsal scales of base of tail granular becoming flatter posteriorly; no median row of transversely enlarged subcaudal scales on original portion of tail; scales of regenerated portion of tail small, flat, rectangular and arranged in semiwhorls; tubercles not extending onto regenerated portion of tail; two enlarged, rounded, smooth, tubercles at base of tail; all postanal scales small, flat, and immbricate.
10 NEW MALAYSIAN CYRTODACTYLUS 587 Coloration in Life. Based on ZRC Dorsal ground color of head, neck, trunk, limbs, and tail gray with slight dark mottling; seven wide, dark, irregular bands between limb insertions; ends of anteriormost body band join with dark, lateral stripes on neck to connect with the posterior portion of a dark, nuchal loop; nuchal loop continous and contacts posterior margins of each eye; dark nape spot enclosed between lateral stripes; large lateral spots occur between some body bands; flanks with weak, dark mottling and light tubercles appearing almost as small spots; faint, light, preorbital stripe; rostrum and supralabials weakly mottled; ventral superciliary row dark; two dark colored bands on original portion of tail, first band at base of tail; regenerated portion of tail uniformly gray; seven short, irregularly shaped dark bands on forelimbs and hind limbs; ventral surfaces of head, body, limbs, and tail beige; gular scales contain a single black spot, pectoral and abdominal scales contain two or three spots except for midventral belly scales which are immaculate; flanks beige with faint, black stippling in each scale; ventral surfaces of limbs and tail darker, stippling present. Variation. The paratypes approximate the holotype closely in coloration. ZRC has a slightly less banded appearance (Fig. 1) in that the dark body bands are broken up and compose more of an irregular blotching pattern. The tail is original with 10 dark bands alternating with nine light bands. ZRC differs in that its nuchal loop is discontinuous on the lateral margins of the nape. Meristic differences are shown in Table 1. Comparisons to Other Sunda Shelf Species. Cyrtodactylus semenanjungenis differs from Cyrtodactylus aurensis, Cyrtodactylus baluensis, Cyrtodactylus consobrinus, Cyrtodactylus fumosus, Cyrtodactylus lateralis, Cyrtodactylus malayanus, Cyrtodactylus marmoratus, Cyrtodactylus matsuii, Cyrtodactylus peguensi, Cyrtodactylus thirakhupti, Cyrtodactylus tiomanensis, Cyrtodactylus yashii, and Cyrtodactylus seribuatensis in having an adult SVL less than 70 mm (Table 2). It differs from C. aurensis and Cyrtodactylus elok in being strongly, as opposed to weakly tuberculated. It differs from Cyrtodactylus cavernicolous and Cyrtodactylus pubisulcus in having tubercles on the forelimbs. Cyrtodactylus semenanjungensis differs from C. consobrinus, C. lateralis, in having less than 54 ventral scales. It differs from C. baluensis, Cyrtodactylus brevipalmatus, C. elok, C. fumosus, Cyrtodactylus ingeri, Cyrtodactylus oldhami, C. peguensis, Cyrtodactylus pulchellus, Cyrtodactylus quadrivirgatus, C. thirakhupti, C. tiomanensis, and, Cyrtodactylus sp. in having more than 47 ventral scales. It differs from C. consobrinus, C. ingeri, C. malayanus, C. oldhami, C. peguensis, C. pulchellus, and C. thirakhupti in lacking transversely enlarged median subcaudal scales. It differs from C. TABLE 1. Mensural and meristic data for the type series of Cyrtodactylus semenanjungensis sp. nov. from Pulau Aur. Abbreviations as in Materials and Methods. R 5 rostral, sn 5 supranasal, L1 5 first supralabial, pn 5 postnasal. 1 5 presence of character state, 0 5 absence of character state. All measurements in millimeters. ZRC ZRC ZRC ZRC sex male female male SVL postmentals degree of contact of postmentals 50% 50% 50% 50% supralabials infralabials scales bordering nostril r, 2sn L1, 2pn r, 2sn L1, 2pn r, 2sn L1, 2pn r, 2sn L1, 2pn longitudinal rows of tubercles paravertebral tubercles ventral scales expanded lamellae on 4th toe narrow lamellae on 4th toe enlarged median subcaudals enlarged preanal scale patch preanal groove preanal pores number of preanal pores body bands blotched reticulate pattern on head TrunkL CrusL TailL 74 66r 47 68r TailW HeadL HeadW HeadH EarL ForeaL OrbD NarEye SnEye EyeEar Internar Interorb yoshii in having transversely enlarged proximal subdigital lamellae. It differs from C. cavernicolous, C. consonbrinus, C. ingeri, C. marmoratus, and C. yoshii in having less than 22 subdigital lamellae on the fourth toe. Cyrtodactylus semenanjungensis
11 588 L. L. GRISMER AND T. M. LEONG TABLE 2. Mensural and meristic data from Sunda Shelf species of Cyrtodactylus from peninsular Malaysia, Borneo, Java, and Sumatra. 1 5 presence of character state, 0 5 absence of character state. aurensis baluensis brevipalmatus cavernicolous consobrinus elok fumosus ingeri lateralis malayanus marmoratus SVL tuberculation moderate to strong tubercles on forelimbs tubercles on hind limbs tubercles on head and/ or occiput tubercles on at least 1/3 of tail ventral scales enlarged median subcaudals proximal subdigital lamellae broad subdigital lamellae on 4th toe contact of posterior thigh scales abrupt enlaged femoral scales * 1 femoral pores preanal groove enlarged preanal scales preanal pores preanal and femoral pores/scales continuous reticulate pattern on head body banded body blotched body striped differs from all other species except C. baluensis, C. brevipalmatus, C. marmoratus, Cyrtodactylus matsuii, C. oldhami, C. pulchellus, C. tiomanensis, C. sworderi, and C. seribuatensis in having an abrupt transition between the posterior and ventral femoral scales. Cyrtodactylus semenanjungensis lacks a series of enlarged femoral scales such as those found in C. baluensis, C. brevipalmatus, C. consobrinus, C. fumosus, C. malayanus (3 4 enlarged scales distally), C. marmoratus, C. oldhami, C. pulchellus, C. quadrivirgatus, C. sworderi, C. thirakhupti, C. tiomanensis, and C. seribuatensis. It differs from C. baluensis, C. brevipalmatus, C. consobrinus, C. fumosus, C. marmoratus, C. pulchellus, and C. sp. in lacking femoral pores. Cyrtodactylus semenanjungensis has a preanal groove unlike C. baluensis, C. brevipalmatus, C. consobrinus, C. elok, C. fumosus, C. ingeri, C. lateralis, C. malayanus, C. matsuii, C. oldhami, C. peguensis, C. quadrivirgatus, C. yoshii, C. sworderi, C. thirakhupti, and C. seribuatensis which lack a preanal groove. It differs from C. matsuii and C. yoshii by having enlarged preanal scales. It differs from all other species except C. aurensis, C. cavernicolous, C. elok, C. ingeri, C. lateralis, C. malayanus, C. matsuii, and C. thirakhupti in lacking preanal pores. Cyrtodactylus semenanjungensis differs from C. baluensis, C. cavernicolous, C. consobrinus, C. ingeri, C. malayanus, C. matsuii, and C. peguensis in lacking a light-colored reticulate pattern on the top of the head as opposed to the top of the head being generally unicolor. Cyrtodactylus semenanjungensis differs from all other species except C. aurensis, C. cavernicolous, C. consobrinus, C. malayanus, C. peguensis, C. pulchellus, C. thirakhupti, and C. tiomanensis in having a distinct, adult banding pattern. Distribution. Cyrtodactylus semenanjungensis presumably ranges throughout the lowland forests from at least the vicinity of Jemaluang, southward 50 km to the foothills of Gunung Panti, Gunung Panti Besar, and Gunung Muntahak. Natural History. All specimens were found in lowland rain forest with adjacent freshwater swamp forest. ZRC and ZRC were found at night while sitting on the surface of leaves of small trees m above the ground. The others were found in the vicinity of small (approximately 1 m wide), meandering streams. Other geckos found sympatric with C. semenanjungensis were C. consobrinus, C. sworderi and Cnemaspis kendalli. Etymology. The specific epithet, semenanjungensis, is derived from the Malay word semenanjung meaning peninsula and is in reference to this species distribution on Peninsular Malaysia.
12 NEW MALAYSIAN CYRTODACTYLUS 589 TABLE 2. Extended. matsuii aurensis oldhami pubisulcus peguensis pulchellus quadrivirgatus semenanjungensis sworderi thirakhupti tiomanensis yoshii seribuatensis , , , DISCUSSION To date there has been no comprehensive phylogenetic analysis of the genus Cyrtodactylus, and even demonstrating its monophyly has proven difficult. Despite the transfer of several species into different genera (see Kluge, 1983; Szcerbak and Golubev, 1977, 1984, 1986; Ulber and Gericke, 1998), the composition of Cyrtodactylus still remains questionable (Bauer et al., 2003). Thus, in the absence of a phylogenetic hypothesis, determining the species to which C. semenanjungensis is most closely related is not possible. Cyrtodactylus semenanjungensis superficially resembles C. quadrivirgatus and C. sworderi (with which it is sympatric) in general aspects of coloration, body size and scale counts (Table 1). However, to hypothesize that these three species share some unique relationship exclusive of other species of Cyrtodactylus would be little more than conjecture. The presence of an undescribed species from this portion of Malaysia where the forests are rapidly being converted into oil palm plantations, underscores the necessity for additional fieldwork. At present, there are only two other species known to be restricted to this general area; Rhacophorus tunkui (Kiew, 1987) and C. sworderi (Smith, 1930). Acknowledgments. For field assistance, we thank H. Kaiser. For the loan of material we thank H. K. Voris and A. Resetar (FMNH) and K. K. P. Lim (ZRC). We to thank officials of the Environmental Planning Unit, Prime Minister s Department for permission to do research in Malaysia and for the issuance of a research permit (40/200/19 SJ.1105). A. Bauer, J. Wiens, and N. Yyakkob provided helpful comments on the manuscript. LITERATURE CITED BAUER, A. M Two new species of Cyrtodactylus (Squamata: Gekkonidae) from Myanmar. Proceedings of the California Academy of Sciences 53: Descriptions of seven new Cyrtodactylus (Squamata: Gekkonidae) with a key to the species of Myanmar. Proceedings of the California Academy of Sciences 54: BAUER, A. M., AND K. HENLE Familia Gekkonidae (Reptilia, Sauria). Part 1 Australia and Oceania. Das Tierreich 109(part), Walter de Gruter, Berlin, Germany. BAUER, A. M., O. S. G. PAUWELS, AND L. CHANHOME A new species of cave-dwelling Cyrtodactylus (Squamata: Gekkonidae) from Thailand. Natural History Journal of the Chulaongkorn Univ. 2:19 29.
13 590 L. L. GRISMER AND T. M. LEONG BAUER, A. M., M. SUMONTHA, AND O. S. G. PAUWELS Two new species of Crytodactylus (Reptilia: Squamata: Gekkonidae) from Thailand. Zootaxa 376:1 *18. DAS, I., AND L. J. LIM A new species of Cyrtodactylus (Sauria: Gekkonidae) from Pulau Tioman, Malaysia. Raffles Bulletin of Zoology 48: DRING, J. C. M Amphibians and reptiles from northern Trengganu, Malaysia, with descriptions of two new geckos: Cnemaspis and Cyrtodactylus. Bulletin British Museum of Natural History 34: GRISMER, L. L A new species of Bent-Toed Gecko (Cyrtodactylus Gray 1827) from Pulau Aur, Johor, West Malaysia. Journal of Herpetology 39: HIKADA, T Bornean gekkonid lizards of the genus Cyrtodactylus (Lacertilia: Gekkonidae) with descriptions of three new species. Japanese Journal of Herpetology 13: IINGER, R. F., AND W. KING A new cave-dwelling lizard of the genus Cyrtodactylus from Niah. Sarawak Museum Journal 10: KIEW, B. H An annotated checklist of the herpetofauna of Ulu Endau, Johore, Malaysia. Malay Nature Journal 41: KLUGE, A. G Cladistic relationships among gekkonid lizards. Copeia 1983: Gekkotan lizard taxonomy. Hamadryad 26: MANTHEY, U., AND W. GROSSMANN Amphibien & Reptilien Südostasiens. Natur und Tier Verlag, Münster, Germany. PAUWELS, O. S. G., A. M. BAUER, M.SUMONTHA, AND L. CHANHOME Cyrtodactylus thirakhupti (Squamata: Gekkonidae), a new cave-dwelling gecko from southern Thailand. Zootaxa 772:1 11. ROOIJ, N. DE The reptiles of the Indo-Australian Archipelago. I. Lacertilia, Chelonia, Emydosauria. E. J. Brill, Leiden, The Netherlands. SMITH, M. A The Reptilia and Amphibia of the Malay Peninsula. Bulletin of the Rafflels Museum 3:1149. SZCZERBAK, N. N., AND M. L. GOLUBEV Systematics of the Palearctic geckos (genera Gymnodactylus, Bunopus, Alsophylax). Proceedings of the Zoological Institute, Academy of Sciences of the USSR 74: [in Russian] On generic assigment of the Palearctic Cyrtodactylus lizard species (Reptilia, Gekkonidae). Vestnik Zoologii 2:50 56 [in Russian] Gecko Fauna of the USSR and Continuous Regions. Naukova Dumka, Kiev. Society for the Study of Reptiles and Amphibians Translation, St Louis, MO. TAYLOR, E. H The lizards of Thailand. Univ. of Kansas, Science Bulletin 54: ULBER, T., AND F. GERICKE Zur Problematik der Verwandtschaftsverhältnisse in der Gattung Cyrtodactylus Gray 1827 und Bemerkungen zur Gattung Nactus Kluge 1983 (Reptilia: Sauria: Gekkonidae). Der Versuch einer auch philosophischen Analyse. Veröffentlichungen des Naturhistorisches Museum Schloss Bertholdsburg, Schleusingen 3: YOUMANS T. M. AND L. L. GRISMER Description of a new species of Cyrtodactylus (Reptilia: Squamata: Gekkonidae) from the Seribuat Archipelago, West Malaysia. Herpetological Natural History 5:in press. Accepted: 11 August APPENDIX 1 Material Examined Abbreviations for institutions are BM, British Museum (Natural History), London; FMNH, Chicago Field Museum of natural History, Chicago; LSUHC, La Sierra University Herpetological Collection, La Sierra University; ZRC, Zoological Reference Collection in the Raffles Museum of Biodiversity Research, National University of Singapore. Cyrtodactylus baluensis ZRC , , East Malaysia, Sabah, Kinabalu, ZRC , northern Borneo, ZRC , Brunei, Temburong, Kuala Belalang. Cyrtodactylus cavernicolus LSUHC , ZRC , , East Malaysia, Sarawak, Niah Cave. Cyrtodactylus elok ZRC , , West Malaysia, Pahang, Raub, Lakum Forest Reserve. Cyrtodactylus formosus ZRC , , Indonesia, Java, Sukabumi. Cyrtodactylus ingeri LSUHC , East Malaysia, Sabah, Turtle Island, ZRC , East Malaysia, Sabah, Poring. Cyrtodactylus consobrinus LSUHC 4019, 4389, , West Malaysia, Selangor, Kepong, Forest Research Institute Malaysia, LSUHC 4912, , West Malaysia, Pahang, Sungai Lembing Logging Camp, LSUHC 4062, East Malaysia, Sarawak, near Niah Cave. Cyrtodactylus fumosus FMNH , Indonesia, North Sulawesi, Lembeh I. Cyrtodactylus malayanus FMNH , , East Malaysia, Sarawak, 3rd Division, Kapit District, Mengiong River, Nanga Tekalit Camp. Cyrtodactylus marmoratus, ZRC , Indonesia, West Java; ZRC , , , Australia, Christmas Island. Cyrtodactylus matsuii ZRC , East Malaysia, Sabah, Crocker Range; Cyrtodactylus oldhami, ZRC , , 2,5230, Thailand, Phuket, Kathu. Cyrtodactylus pubisulcus LSUHC 4069, East Malaysia, Sarawak, near Niah Cave. Cyrtodactylus pulchellus LSUHC 6637, West Malaysia, Selangor, Genting Highlands, ZRC , , West Malaysia, Perak, Bukit Larut, LSUHC 6668, , 6785, 6829, West Malaysia, Seberang Perai, Pulau Penang, Ampangan Air Hitam. Cyrtodactylus quadrivirgatus LSUHC 4018, 4823, West Malaysia, Selangor, Kepong, Forest Research Institute Malaysia; ZRC , West Malaysia, Perak, Bulik Larut, LSUHC 4813, 5022, 5101, 5173, 5517, 5562, 5582, 6136, 6146, West Malaysia, Pahang, Pulau Tioman; LSUHC 4980, 5017, West Malaysia, Pahang, Sungai Lembing Logging Camp; LSUHC , 5640, West Malaysia, Perak, Temengor, PITC Logging Camp; LSUHC 6069, 6986, 6106, West Malaysia, Pahang, Pekan; ZRC , , , , ZRC , , , , , , , , , , ; Singapore, Nee Soon Swamp.
14 NEW MALAYSIAN CYRTODACTYLUS 591 Cyrtodactylus semenanjungensis ZRC , , West Malaysia, Johor, foothills of Gunung Panti, ZRC , West Malaysia, Johor, ;7 km west of Jemaluang. Cyrtodactylus tiomanensis LSUHC , , 3847, , 4587, 4590, 4597, , 5044, 5411, 5479, 5512, , , 6268, West Malaysia, Pahang, Pulau Tioman. Cyrtodactylus yoshi ZRC , East Malaysia, Sabah, Poring. Cyrtodactylus sp. LSUHC , , 5243, 5578, West Malaysia, Pahang, Pulau Seribuat; LSUHC 5522, West Malaysia, Pahang, Pulau Sembilang; LSUHC 5604, , , West Malaysia, Johor, Pulau Sibu; LSUHC West Malaysia, Johor, Pulau Sibu Tengah. Journal of Herpetology, Vol. 39, No. 4, pp , 2005 Copyright 2005 Society for the Study of Amphibians and Reptiles New Species of Blindsnake from Rossel Island, Papua New Guinea FRED KRAUS Bernice P. Bishop Museum, 1525 Bernice Street, Honolulu, Hawaii 96817, USA; ABSTRACT. I describe a new species of blindsnake of the genus Typhlops from Rossel Island, off the southeastern tip of New Guinea. The new species is a member of the Typhlops ater species group and is characterized by having 18 scale rows, 343 middorsal scales, T-V supralabial-imbrication pattern, a distinct pupil, single subocular scale, and by lacking a presubocular scale. Its closest living relative is probably Typhlops inornatus, known from forested habitats on the nearby mainland of New Guinea. The new species is known from only two specimens from northeastern Rossel Island, and it remains uncertain whether it occurs on adjacent islands of the Louisiade Archipelago. Typhlopid blindsnakes of the Papuan region were summarized by McDowell (1974), who recognized two genera, Typhlops and Typhlina, containing a total of 16 species. This work was expanded on by Wallach (1995, 1996a,b), resulting in the current recognition of three genera: Acutotyphlops with four species, Ramphotyphlops with 12 species, and Typhlops with seven. All Papuan Typhlops, with the exception of Typhlops diardi (of questionable occurrence in New Guinea) and Typhlops kraali (from the Kei Islands), are placed within the Typhlops ater species group, which is distinguished from geographically proximate congeners by having glands present beneath the central portions of the head scales (McDowell, 1974; Wallach, 1996a). The other seven members of that species group range from southern Asia eastward through Indonesia and the Philippines (Wallach, 1996a). Within New Guinea, T. ater is known from western Papua (Irian Jaya) and associated islands, Typhlops depressiceps from northern Papua New Guinea and Panaeati Island in the Louisiade Archipelago, Typhlops inornatus from the Central Highlands and Owen Stanley Range of Papua New Guinea, and Typhlops fredparkeri and Typhlops mcdowelli from the vicinity of Port Moresby on the southwestern coast of the Papuan Peninsula (McDiarmid et al., 1999). During the course of continued biotic surveys of Milne Bay Province, at the southeastern extreme of New Guinea, I discovered a new species of Typhlops of the T. ater species group on Rossel Island. This island is the most remote of the Louisiade Archipelago and the farthest southeastern extent of Papua New Guinea. I describe the new species herein. MATERIALS AND METHODS Specimens were collected under applicable national and provincial permits, fixed in 10% buffered formalin, and transferred to 70% ethanol for storage. Total length measurements were made to the nearest 0.5 mm in the field with a plastic ruler; mass was measured to the nearest 0.1 gram in the field with a Pesola scale. All other length measurements were taken to the nearest 0.1 mm under a dissecting scope fitted with an ocular micrometer. Sex was determined by dissection. Diagnostic features and comparisons to other species were based on data provided in McDowell (1974) and Wallach (1993, 1996a) and by reference to specimens housed in the Bernice P. Bishop Museum, Honolulu (BPBM). Specimens are deposited in the BPBM. Locality coordinates for the new species use GPS datum AUS 66 (Appendix 1).
15 592 FRED KRAUS TABLE 1. Features distinguishing Typhlops hades from other round-snouted Papuan members of the Typhlops ater species group. T. T. Character fredparkeri inornatus T. ater T. hades Total length (mm) Midbody scale rows Transverse scale rows Total length/ midbody diameter (mm/g) Supralabial imbrication pattern T-V T-V T-II T-V Nasals in dorsal contact? no no yes no Presubocular scale present? no no yes no Typhlops hades sp. nov. Holotype. BPBM (field tag FK 10449), adult male, collected by F. Kraus in forest along Rupu River at Bibikea, S, E, 280 m, Rossel Island, Milne Bay Province, Papua New Guinea, on 14 May Paratype. BPBM 20820, adult female, obtained by native collector at Cheme, S, E, 0 20 m, Rossel Island, Milne Bay Province, Papua New Guinea, on 17 May Diagnosis. A small, thin species of Typhlops having a rounded snout, distinct pupil in the eye, 18 scale rows throughout, 343 middorsal scales between the rostral and tail spine, T-V supralabial-imbrication pattern (for definitions of these patterns, see Wallach, 1993), one subocular scale, head glands evenly but sparsely dispersed among the anterior head scales but absent from the centers of the ocular and subocular scales, and anterior two-thirds of the eye covered by the preocular plate. Typhlops hades belongs to the T. ater species group (McDowell, 1974) based on the presence of head glands in the centers of the head shields in addition to their anterior margins (Wallach, 1996a). Among members of this species group, T. hades may be distinguished from Typhlops depressiceps, Typhlops fredparkeri, T. inornatus, T. mcdowelli, and Typhlops oligolepis in having 18 (vs. 16 in Typhlops fredparkeri and T. oligolepis and 20þ in the remaining species) midbody scale rows; from Typhlops beddomii, T. hedraeus, and Typhlops tindalli in having a subocular scale and supralabial-imbrication pattern T-V (vs. T-II in the three Asian species); and from the geographically remote Typhlops andamanensis, T. ater, Typhlops bisubocularis, and Typhlops floweri in lacking a presubocular. It further differs from the first three of those species in having supralabial-imbrication pattern T-V (vs. T-II). Typhlops hades is the only typhlopid from Papua New Guinea to have the combination of head glands in the centers of the head shields and 18 midbody scale rows. In Wallach s (1996) key to typhlopids from Papua New Guinea, T. hades would key out to T. inornatus. In addition to number of midbody scale rows, the new species differs from T. inornatus in being of smaller size, narrower habitus (TL/mass mm/g in T. hades and mm/g in T. inornatus; Table 1), having approximately two-thirds of the eye lying under the preocular plate (vs. 50% or less in T. inornatus), and having no head glands in the centers of the ocular and subocular shields (generally but not invariably present in T. inornatus). The new species also has far fewer glands present in the centers of the rostral, preocular, and superior nasal scales. This is most easily compared under the preocular scales because of their reduced gland numbers. For this FIG. 1. (A) Lateral and (B) dorsal views of the head of Typhlops hades holotype (BPBM 20819).
16 NEW BLINDSNAKE FROM NEW GUINEA 593 scale, T. hades has centrally arrayed glands (Fig. 1) vs. 39 in the preocular of a typical T. inornatus. Description of Holotype. Adult male. Snout rounded in dorsal and lateral views. Rostral large (0.5 head width), largely oval in shape but somewhat constricted medially at level of nares, posterior border reaching halfway between eye and naris. Nasals separated dorsally by prefrontal; superior nasal large, with a nearly straight posterior margin, rounded dorsally and ventrally. External naris close to rostral; superior nasal suture complete, extending anterodorsally at 458 angle from naris to rostral; inferior nasal suture complete, contacting second supralabial. Prefrontal, frontal, supraoculars, parietals, and interparietal all equal in size, except left parietal, which is fused with adjacent body scale. Preocular large, triangular; larger than ocular but smaller than supranasal. Ocular large, approximately half size of preocular, extending dorsally well above preocular, extending ventrally to midpreocular level, bordered posteroventrally by a subocular of half its size. Eye with distinct pupil and iris, situated at the widest point of ocular and in its lower half, anterior two-thirds covered by preocular plate. Three postoculars between parietal and fourth supralabial. Four supralabials, third the largest, all except first with long axis oblique to long axis of body. Supralabial-imbrication pattern T-V, posterior border of second supralabial overlaps anteroventral margin of preocular, that of third supralabial overlaps anteroventral margin of subocular. Mental hexagonal, wider than long, projecting beyond curve of lower jaw and fitting into notch on upper lip when mouth is closed. Infralabials two on right, three on left. Scale rows ; 343 middorsal scales between the rostral and tail spine; 19 subcaudals; 20 dorsocaudals; small, thin apical spine on tail that extends horizontally and posteriorly. Rostral, supranasals, preoculars, prefrontal, supraoculars, and supralabials 1 3 with head glands, these glands restricted to anterior margins of the supraoculars but arrayed along both anterior margins and throughout centers of the other scales (Fig. 1). Supranasals with 10 (right) and 8 (left) glands along anterior margin and 41 (right) and 39 (left) throughout remainder of scales. Preoculars with 10 (right) and 11 (left) glands along anterior margins and 10 (right) and 9 (left) in remainder of scales. Dorsum dark brown, darkest on 7 9 middorsal scale rows and becoming progressively lighter laterally and ventrally. Lateral margins of middorsal scales salmon pink, which gradually lighten to pale pink-brown ventrally. The overall impression under magnification is that of a dark brown animal with a slightly pinkish cast. Infranasal, ventral portion of rostral, and anterior of lower jaw unpigmented, giving the impression of a white tip to the face. Measurements. Measurements in millimeters. Total length 127, tail length 5.2, head diameter 2.6, nuchal diameter 2.5, midbody diameter 2.7, cloacal diameter 2.6, midtail diameter 2.3, mass 0.7 g. Variation. The single paratype is female, larger than the holotype, and with the following measurements: total length 143, tail length 4.8, head diameter 2.8, nuchal diameter 2.6, midbody diameter 3.9, cloacal diameter 3.1, midtail diameter 3.0, mass 1.4 g. The paratype also has scale rows and 343 middorsal scales between the rostral and tail spine. It has 17 subcaudals and 17 dorsocaudals. Head scales are as for the holotype, including having two infralabials on the right side and three on the left. The paratype appears to have been preserved just prior to ecdysis, so the specimen is opaque milky gray, darker above and gradually lightening laterally and ventrally. On the head, eyes and glands are difficult to discern for the same reason and glands cannot be reliably counted. Ecological Notes. The holotype was collected while crossing the ground in early evening in our camp erected in a relatively flat floodplain containing old second-growth lowland rain forest with a canopy height of ;25 m. Gently sloping hills adjacent to camp were covered with scree overlain by a moderate amount of undergrowth. The entire understory and soil for a few kilometers around camp were disturbed by an extensive landslide triggered during a 1993 hurricane. The paratype was brought in by a local villager and was likely obtained while working in his garden. Rain was frequent during our stay on Rossel and may have facilitated the surface activity of the holotype. Etymology. The trivial epithet is the name of the Greek god of the underworld and is a noun in apposition. Distribution. Known only from the northeast end of Rossel Island in the Louisiade Archipelago, off the southeastern tip of New Guinea (Fig. 2). The two localities from which the species was taken are only 2.5 km apart. REMARKS Among members of the T. ater species group, T. hades is geographically most proximate to T. depressiceps, which is also reported from the Louisiade Archipelago (Wallach, 1996a; McDiarmid et al., 1999). But T. hades is of doubtful close relationship to that species, given the latter s beaklike snout, much higher number (. 600) of middorsal scales (Wallach, 1996a), and much
17 594 FRED KRAUS FIG. 2. Map of southeastern New Guinea and offshore islands, showing the type locality of Typhlops hades in northeastern Rossel Island (solid circle). greater number of head glands (e.g., ;37 in the centers of the preoculars, pers. obs.). Typhlops hades is likely most closely related to T. inornatus and T. fredparkeri, which are found on the adjacent mainland of New Guinea (McDowell, 1974; Wallach, 1996a; Kraus and Allison, 2004) and which represent the only geographically proximate members of the T. ater species group that have rounded snouts (Wallach, 1996a). Typhlops ater also has a rounded snout but differs in having a T-II supralabial-imbrication pattern, a presubocular scale, the nasals in contact dorsally (Table 1), and occurs at the far western extreme of New Guinea, approximately 2400 km distant from Rossel Island. Typhlops inornatus, like T. hades, inhabits forested habitats and occurs on the adjacent mainland of Milne Bay Province (Kraus and Allison, 2004). In contrast, T. fredparkeri is known only from the savannah region around Port Moresby on the opposite side of the Papuan Peninsula from the Louisiade Islands. Hence, it seems most likely that T. inornatus represents the closest living relative to T. hades.in as much as the Louisiade Islands have probably never had a subaerial connection to mainland New Guinea (H. Davies, Univ. of Papua New Guinea, Department of Geology, pers. comm.), the ancestor of T. hades presumably colonized Rossel Island via a waif dispersal event. Whether the species occurs on other islands of the Louisiades remains to be seen, but my work on Sudest and Misima has failed to produce it. Wallach (1996) noted that the T. ater species group could largely be divided into two subgroups:apapuansectionwith20ormoremidbody scale rows and a T-V supralabial-imbrication pattern and an Asian section with 18 or fewer midbody scale rows and a T-II pattern. The only exception to this dichotomy was the Thai species T. floweri, which has 18 midbody scale rows but a T-V pattern. To this exception may now be added T. hades, which has the same annectant combination of characters and further confounds easy recognition of relationships within this group. Acknowledgments. I thank C. Bernard, R. Henry, S. John, and F. Malesa for field assistance; D. Mitchell, C. Graham, and Conservation International for logistical assistance in Milne Bay Province; C. Kembwa and I. Yidika for logistical assistance on Rossel Island; C. Kishinami for specimen curation; B. Evans for preparing the map; the PNG National Museum and Art Gallery for providing in-country collaborative assistance; and the PNG Department of Environment and Conservation, PNG National Research Institute, and Milne Bay Provincial Government for permission to work in Milne Bay Province. This research was supported by National Science Foundation grant DEB
18 NEW BLINDSNAKE FROM NEW GUINEA 595 This is contribution to the Pacific Biological Survey. LITERATURE CITED KRAUS, F., AND A. ALLISON New records of reptiles and amphibians from Milne Bay Province, Papua New Guinea. Herpetological Review 35: MCDIARMID, R. W., J. A. CAMPBELL, AND T. A. TOURÉ Snake Species of the World: A Taxonomic and Geographic Reference. Vol. 1. The Herpetologists League, Washington, DC. MCDOWELL, S. B A catalogue of the snakes of New Guinea and the Solomons, with special reference to those in the Bernice P. Bishop Museum. Part I. Scolecophidia. Journal of Herpetology 8:1 57. WALLACH, V The supralabial imbrication pattern of the Typhlopoidea (Reptilia: Serpentes). Journal of Herpetology 27: A new genus for the Ramphotyphlops subocularis species group (Serpentes: Typhlopidae), with description of a new species. Asiatic Herpetological Research 6: a. Two new blind snakes of the Typhlops ater species group from Papua New Guinea (Serpentes: Typhlopidae). Russian Journal of Herpetology 3: b. The systematic status of the Ramphotyphlops flaviventer (Peters) complex (Serpentes: Typhlopidae). Amphibia-Reptilia 17: Accepted: 11 August APPENDIX 1 Specimens Examined Typhlops depressiceps. Papua New Guinea: New Ireland Province: Weitin River Valley, 13 km north, 10.5 km west of river mouth, S, E, 240 m (BPBM 11904). Typhlops inornatus. Papua New Guinea: Milne Bay Province: Bunisi Village, S, E, 1420 m (BPBM 17236); Siyomu Village, S, E, 1300 m (BPBM 17237); Ikara Village, S, E, 800 m (BPBM 17238); Morobe Province: Upper Watut River, near Bulolo (BPBM 2772); along Dunch River, 5.6 km northwest of summit Mt. Shungol, S, E, 750 m (BPBM ). Journal of Herpetology, Vol. 39, No. 4, pp , 2005 Copyright 2005 Society for the Study of Amphibians and Reptiles Effects of Body Mass, Feeding, and Circadian Cycles on Metabolism in the Lizard Sceloporus occidentalis JOHN H. ROE, 1,2 WILLIAM A. HOPKINS, 1,3 AND LARRY G. TALENT 4 1 University of Georgia, Savannah River Ecology Laboratory, Aiken, South Carolina 29802, USA 4 Oklahoma State University, Stillwater, Oklahoma USA; ABSTRACT. We examined aspects of pre- and postprandial metabolism in the diurnally active Western Fence Lizard, Sceloporus occidentalis, by measuring rates of oxygen consumption (Vo 2 ) and carbon dioxide production (Vco 2 )at308c. Sceloporus occidentalis exhibited strong circadian variation in metabolism that continued throughout digestion, with diurnal peaks in metabolism up to four times as high as nocturnal minimum values (standard metabolic rate, SMR). Metabolism increased with increasing body size (mass range g), with mass exponents ranging from Metabolism of lizards fed meals equivalent to 1.4, 2.9, and 3.9% of their body mass was elevated above fasting metabolism, although significant differences in metabolism were not detected among the three meal sizes. Maximum metabolism during digestion was from times that of maximum fasting metabolism, a value similar to that of other small, frequently feeding lizards. Specific dynamic action (SDA) ranged from ml O 2 and ml CO 2, or kj, which is equivalent to % of the ingested energy. Mean respiratory quotients (RQ) ranged from , indicating lipids were the primary energy substrate used during both fasting and digestion. 2 Corresponding Author. Present address: Applied Ecology Research Group, University of Canberra, Canberra, Australian Capitol Territory 2601, Australia; Knowledge of metabolic energy expenditure patterns has provided a framework for investigating physiological, behavioral, and ecological adaptations in reptiles (e.g., Congdon et al., 1982). Measuring metabolism permits identifica-
19 596 J. H. ROE ET AL. tion of sources of individual variation and broadscale patterns of energy use at multiple levels of biological organization. For example, amongspecies comparisons of metabolism suggest ecological and phylogenetic relationships greatly influence energy expenditure in reptiles (Andrews and Pough, 1985; Secor and Diamond, 2000). Studies of metabolism have also identified how temperature, body mass, time of day, sex, and season influence variation in ecological energetics among individuals or populations (Beaupre, 1993; Beaupre et al., 1993; Angiletta, 2001). A rich empirical database on lizard metabolism has facilitated comparisons among lizards and between lizards and other taxa (e.g., Bennett and Dawson, 1976; Andrews and Pough, 1985; Waldshmidt et al., 1987, Christian et al., 1997). However, the influence of feeding on metabolism in lizards remains relatively underexplored compared to other aspects of their physiology. A growing literature base on standard metabolic rate (SMR, the metabolic rate of a postabsorptive animal at rest at a specified temperature during the inactive phase of its circadian cycle; Bennett and Dawson, 1976) and specific dynamic action (SDA, the increased energy expenditure associated with digestion, assimilation, and biosynthesis; Kleiber, 1975) has demonstrated how important the relationship between foraging ecology and metabolism is for understanding energy use in snakes (Secor and Diamond, 2000; Secor, 2001). More complete knowledge of SDA in lizards, which also vary widely in foraging ecology (Cooper, 1994), could yield valuable insight on energy use patterns among lizards, and between lizards and other groups of reptiles. In this study, we examined aspects of pre- and postfeeding metabolism in a phrynosomatid lizard, the Western Fence Lizard (Sceloporus occidentalis). Our aims were to determine whether circadian cycles, body mass, and meal size influenced oxygen consumption and carbon dioxide production rates (Vo 2 and Vco 2, respectively). MATERIALS AND METHODS Study Species. Sceloporus occidentalis is a diurnally active phrynosomatid found in a variety of habitats and ranges from Mexico to Canada between the California coast and western Utah in the United States. Foraging behavior in Sceloporus spp. is generally classified as sit-and-wait, and most individuals feed frequently and usually have food in their stomach during the active season (Cooper, 1994; Niewiarowski and Waldshmidt, 1992). We established a research colony of S. occidentalis at the Savannah River Ecology Laboratory in Aiken, South Carolina, with the parental stock originating from the San Joaquin Valley, California. Within six weeks of hatching, lizards were maintained in a room with a 10:14 L:D cycle (photophase starting at 0630 and scotophase at 1630) and a temperature range of C. Lizards were housed in plastic cages ( cm) with screen lids. Each cage contained sand, a hide plate for refuge, a water dish, a dish filled with a calcium supplement (Rep-calä), and a basking platform under a full spectrum lamp (40 60 W) at one end for thermoregulation. Lizards were fed crickets dusted with vitamin supplement (Rep-cal Herptiviteä) daily. To eliminate variation due to sex, we only used males (N 5 11, F 1 F 3 generations) between g. Minimum size for sexual maturity in male S. occidentalis is approximately 12 g, which can be attained at the age of four months in captivity, or approximately two years in the wild (Talent et al., 2002). Metabolic Measurements. We measured metabolic rates of S. occidentalis indirectly as Vo 2 and Vco 2 using a computer controlled, closed system respirometer (Micro Oxymax, Columbus Instruments, Columbus, OH) described by Hopkins et al. (1999, 2004). Metabolic measurements occurred between 27 October 2003 and 26 February For each lizard, we measured fasting metabolism in two separate trials, and once after eating crickets equal to (6 SE), , and % of lizard body mass. A meal size of approximately 4% represents the upper limit of what S. occidentalis would reliably eat in the laboratory. First and last metabolic trials for each lizard were under fasting conditions, and order of feeding trials was determined by the lizard s motivation to eat. Before each metabolic trial, lizards were fasted for 48 h to ensure that they were postabsorptive. For feeding trials, lizards were offered 1 13 crickets (depending on meal and body size) between 0745 and 0815 h. Mass of crickets was determined on an electronic balance (to the nearest milligram) before being offered to the lizards. Any uneaten crickets were removed and their mass determined once lizards no longer showed interest in feeding, and the mass eaten was calculated as the difference between crickets offered and crickets remaining. Lizards were then placed in individual glass respirometry chambers (600 ml for lizards, 9 g, and 1100 ml for lizards. 9 g) within an environmental cabinet in constant darkness at 308C, which is within the range of active body temperatures experienced by this species in the wild (Bennett and Gleeson, 1976). Each chamber was covered with paper to reduce external stimuli. The respirometer was started between 0840 and 0900 h, and the first measurement occurred h after feeding. Each chamber was sampled at one-hour intervals for 48 h, a time frame within which other frequently feeding, small lizards complete digestion (Beaupre et al.,
20 SCELOPORUS OCCIDENTALIS METABOLISM ; Robert and Thompson, 2000; Iglesias et al., 2003). After every third sample, chambers were refreshed with dry ambient air (dried over a column of Drierite) equaling seven times the chamber headspace (volume of the chamber minus the volume of the lizard). Air was pumped from each respiratory chamber through a drying column containing magnesium perchlorate before passing through a gas sensor. Rates of gas exchange were calculated and adjusted for standard temperature and pressure by the respirometer software (Micro-Oxymax, vers. 6.09, Columbus Instruments, Columbus, OH). Lizards were undisturbed throughout metabolic measurements. After each trial, lizards were returned to their cages (outside of the environmental cabinet) and allowed access to water until subsequent metabolic measurements began. Data Handling and Analysis. Prior to all analyses, all metabolic variables and body mass were log 10 -transformed to better approximate normal distributions and equal variances. Because fasting metabolism was measured during two trials for each lizard, we present fasting metabolism as the mean of the two trials for each measurement period and use mean values in all analyses. Because lizards commonly exhibit daily fluctuations in metabolism resulting from activity and circadian rhythms, procedures to eliminate the influence of elevated gas exchange rates associated with such variation are required for accurate estimates of SMR. We estimated SMR for each individual by truncating the upper 75% of metabolic measurements and taking the mean of the remaining 25% of measurements. For this dataset, the 11 lowest of 45 Vo 2 and Vco 2 measures constitute the lower 25% of values. Similar techniques that use a standardized lower proportion of the measures have been successfully used to estimate SMR in reptiles that exhibit daily Vo 2 variation (Dorcas et al., 2004; Hopkins et al., 2004; Roe et al., 2004). We examined the functional relationship between SMR and body mass using regression analysis. Similar to that of fasting metabolic measurements, measurements of digestive metabolism are complicated by variance of gas exchange rates associated with circadian rhythms and activity as well. Curve smoothing methods can be used to reduce the influence of undesired sources of metabolic variation from digestive metabolic estimates (Andrade et al., 1997; Powell et al., 1999; Hopkins et al., 2004; Roe et al., 2004). However, the variance associated with circadian rhythms was so great in S. occidentalis that such smoothing techniques could not be adopted. Instead, we estimated the total volume of oxygen consumed and carbon dioxide produced during fasting and digesting trials as the integral of total Vo 2 and Vco 2 (Fig. 1). These total gas exchange FIG. 1. Oxygen consumption of a representative Sceloporus occidentalis (7.17 g) while fasting (A) and after eating crickets equivalent to 1.4, 2.9, and 3.9% of their body mass (B) at 308C in complete dark. Time zero corresponds to the approximate time of meal ingestion (0800) in feeding trials. The solid horizontal lines represent scotophase periods to which lizards were entrained in captivity. The horizontal dashed line represents standard metabolic rate (SMR), and the filled circles on graph A represent the Vo 2 -values used to calculate SMR after the upper 75% were removed. rates represent the sum of numerous components, including SMR, circadian rhythms, activity, and digestion. To examine effects of body mass and meal size on volumes of total O 2 consumed and CO 2 produced, we used repeated measures ANCOVA with lizard body mass (g) as the covariate and a specified compound symmetry covariance structure (PROC MIXED Model, SAS, vers. 8.1, SAS Institute, Cary, NC, 1999). Additionally, we used post hoc tests to examine which treatment groups differed from one another (Solutions for fixed effects, SAS, vers. 8.1, SAS Institute, Cary, NC, 1999). We then examined the functional relationship between body mass, meal size, and O 2 consumption and CO 2 production, using multiple regression analysis. These regression equations allowed us to estimate SDA for any combination of body and meal sizes by subtracting predicted gas volumes for a particular meal size from volumes for a meal