Marina V. Malyutina. Abstract. Introduction

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1 Org. Divers. Evol. 3, Electr. Suppl. 13: (2003) Gesellschaft für Biologische Systematik Revision of Storthyngura Vanhöffen, 1914 (Crustacea: Isopoda: Munnopsididae) with descriptions of three new genera and four new species from the deep South Atlantic Marina V. Malyutina Institute of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 17 Palchevsky St, Vladivostok , Russia Received 25 June 2002 Accepted 21 April 2003 Abstract The deep-sea genus Storthyngura (family Munnopsididae) is revised. Three new genera (Rectisura, Sursumura and Vanhoeffenella) and four new species (Rectisura richardsoni, Sursumura aberrata, Vanhoeffenella georgei, and V. moskalevi) are described from deep-sea basins and trenches of the South Atlantic Ocean. Thirty-three previously described species are placed in new combinations with one of the new genera. Diagnoses are presented for the subfamily Storthyngurinae Kussakin (2003), the genus Storthyngura Vanhöffen, and all new taxa. A key to the six genera in the subfamily is offered, as well as keys to species in Storthyngura and the three new genera. Key words: deep sea, South Atlantic, Crustacea, Asellota, Munnopsididae, new taxa Introduction The munnopsidid genus Storthyngura was erected by Vanhöffen (1914) for a group of 7 species previously placed in Eurycope and the newly proposed S. elegans. Wolff (1962) has presented a key to the species of Storthyngura based on a detailed study of 17 of the 28 species known at that time, including 5 described as new in that work. George & Menzies (1968a) have given a summary of the history of the genus and added the descriptions of 6 new species. In a subsequent paper (George & Menzies 1968b) they listed 38 species of Storthyngura with data for their distribution. Since then, ten more species or subspecies have been described: S. zenkevichi Birstein, 1969; S. paradoxa and S. tenuispinis distincta Birstein, 1970; S. octospinosalis and S. unicornalis Menzies & George, 1972; S. magnifica Chardy, 1976; S. myriamae George & Hinton, 1982; S. torbeni George, 1987; S. parka Malyutina & Wägele, 2001; and S. kussakini Brandt & Malyutina, Wilson & al. (1989) revised the genus Microprotus, demonstrated its close relationship to Storthyngura, and transferred S. paradoxa to Microprotus. They noted that these two genera form a monophyletic taxon within the Munnopsididae Sars, 1869, and stated that formal recognition of this group as a subfamily had to wait until the genus Storthyngura was revised. Malyutina (1999a) erected the new genus Storthyngurella for 3 new species and 5 previously placed in Storthyngura: S. benti Wolff, 1956; S. digitata Menzies, 1962; S. spinosa (Beddard, 1885); S. triplispinosa Menzies, 1962; and S. zenkevichi. Kussakin (2003) placed Microprotus, Storthyngura, and Storthyngurella in the new subfamily Storthyngurinae. In spite of the exclusion of some derived species Storthyngura still is one of the most abundant and diverse deep-sea genera in the family Munnopsididae. Until the present work, it included more than 40 species distributed over all world oceans except the central part of the North Polar Sea and the Nordic Seas: Norwegian, Greenland Seas. Lists of Storthyngura species and data on their distribution

2 were presented in George & Menzies (1968b), and Brandt & Malyutina (2002). The genus Storthyngura contains munnopsidids with spine-like projections on the body and various pleotelson shapes. Storthyngura species are mainly characterized by a strong, vaulted, muscular body up to 5 cm long, although some species are minute, fragile creatures only a few mm long (Fig. 1). Different variations of functionally dependent morphological features can be observed in Storthyngura. For example, in species whose carpi and propodi of pereopods 5-7 are broad, paddle-like, with long marginal plumose setae, pereopods 3 and 4 are much longer than the other legs, and the body is relatively streamlined. Probably, these Storthyngura are able to walk on soft bottoms using the long legs like stilts, and to swim short distances backwards by means of their paddle-like posterior legs. Fittingly, their pleotelson is usually apically pointed and all body spines are directed forwards, increasing the body's dynamic properties. Some Storthyngura species have only very short spines and a rounded pleotelson, resembling spineless Eurycope with a similar correlation of leg sizes and shape. In other species, narrowing of the legs in the posterior pairs is accompanied by a decrease of length differences between the legs, the latter all having similar ambulatory functions. The body is either flattened or all body projections protrude outwards or backwards, and additional setae or cuticular sculptures appear on the surface of the body and on projections. These forms are better adapted for a crawling, creeping life-style. The pattern of body spines distinguishes species of Storthyngura from some similar species of the genera Eurycope and Munneurycope. Perhaps, the ease with which species of Storthyngura can be identified only on the basis of these superficial features can explain why most of the existing species descriptions are too brief and poorly illustrated. Often only a dorsal view of the body and a few details are shown. This circumstance did not facilitate the revision of this large and heterogeneous group. Except for body spines, almost all the 56 characters of Storthyngura mentioned by George & Menzies (1968a) are also common in species of Eurycope and cannot be use to distinguish species groups. George & Menzies (1968b), referring to 156 characters, divided the genus into five groups and 14 subgroups mainly on the basis of pleotelson morphology. However, their subgroups separated species, for example, with truncated or with forked pleotelson tips, and united species with different antennal structure. The inadequacy of this classification has been pointed out by several researchers (Birstein 1969, 1970; Wilson & al. 1989, Malyutina 1999b). For the present revision many specimens of Storthyngura from the South Atlantic, collected by several Russian expeditions of RV Akademik Kurchatov and RV Dmitry Mendeleev, have been investigated. Moreover, two specimens of Storthyngura were identified from the material of the German DIVA expedition (cruise M 48/1 of RV Meteor 2000). Some other species were also studied for differential diagnoses, including the type species, S. elegans (see Malyutina & Wägele 2001). A detailed character analysis revealed that the genus Storthyngura can be split into four genera. Important distinctive characters that have to be described are the following: the structure of peduncular articles of antenna 1, the dorsum of the head (Fig. 3), the anterolateral corners of pereonite 3, the posterior part of the pleotelson (Fig. 1), the morphology of pereopods (especially the carpi and propodi of the last three pairs), and the pleopods (Figs 4, 5). Among these characters, the most important for easy identification of the genus is the structure of the peduncular articles of antenna 1. During the revision, four new species were identified. Illustrated descriptions of them are presented below, along with diagnoses and descriptions of the three new genera, and keys for the identification of the four genera and their species. Terminology and measurements follow Wilson & Hessler (1980) and Wilson (1989). The type material is deposited in the Zoological Museum of Moscow University (ZMMU), Moscow, Russia. Abbreviations used in the text and figures: R = rostrum; A 1, A 2 = antenna 1 and 2; Md = mandible; MdP = mandibular palp; Mx 1, 2 = maxilla 1 and 2; Mxp = maxilliped; P 1-7 = pereopods 1-7; Pl 1-5 = pleopods 1-5; Urp = uropod. Taxonomy Suborder Asellota Family Munnopsididae Sars, 1869 Subfamily Storthyngurinae Kussakin, 2003 Storthyngurinae Kussakin, 2003: 273. Diagnosis. Body with dorsal and lateral spine-like projections. Pereopod 1 with 1 and pereopods 2-4 with 2 coxal projections visible from above. 2

3 Antenna 1 basal article elongate, with distolateral lobe. Squama on article 3 of antenna 2 not articulated. Mandible with proximolateral projection for articulation with head in elongate slot. Male pleopod 1 elongate, often narrowing in the middle part. Female pleopod 2 medial keel low. Uropod elongate, tubular protopod and rami subequal in length. Description (Figs 1-5). Body elongate, ambulosoma (pereonites 1-4) and natasoma (pereonites 5-7 and pleotelson) subequal in width. Head wider than long, without rostrum. Pereonites 1-4 short and broad, movably articulated, pereonite 1 smallest. Pereonites 5-7 convex, fused to each other and with pleon, often with dorsal sutures, anterolateral corners projecting. Pleotelson with 2 or 3 pairs of lateral projections. Clypeus significantly broader than labrum. Antenna 1 basal article ventral side longitudinally concave, article 2 much smaller, inserted on dorsal side of article 1, somewhat behind its frontal margin, articles 3 and 5 elongate, article 4 shortest among first five, in males articles 2 5 broader and stronger than in females; flagellar articles in male short, numerous, in female flagellar articles longer, less numerous. Antenna 2 article 1 triangular, about half as wide as article 2, article 3 with triangular distal projections, proximolateral keel, and low rounded bump dorsally. Mandibular molar process truncated distally, posterior margin of triturative surface with row of denticles and setulose setae, ventral tooth present; palp well developed, subequal in length to mandibular body, terminal article broad, twisted. Maxilla 1 inner endite bent medially, distomedial seta largest among numerous distal setae. Maxillipedal palp inserting in midlength of basis, articles 2 and 3 subequal in width to basis, epipod elongate. All pereopod bases subequal in length. Pereopod 1 shortest, carpus slightly curved, bearing only simple setae. Pereopods 2 4 carpi and propodi straight, bearing strong, unequal bifid ventral setae and sparse simple dorsal setae. Pereopods 5-7 of similar shape and size, subequal in length to pereopod 2, with carpus and propodus only moderately expanded; dactyli of pereopods 2 7 with acute dorsal claw provided with inner acute projection. Male pleopod 2 protopod semicircular, lateral and distal margins with plumose setae, female operculum with or without ventral spine, margins with plumose setae. Pleopod 3 exopod conspiquously narrower than endopod, 2-segmented, with numerous distal plumose setae. Included genera: Storthyngura, Microprotus, Storthyngurella, Vanhoeffenella gen. n., Rectisura gen. n., and Sursumura gen. n. Remarks. The members of Storthyngurinae differ from those of Acanthocopinae Wolff, 1962 (Fig. 2a) in possessing the usual munnopsidid shapes of male pleopods 1 and 2 (pleopods of Acanthocope as in Fig. 2), uropods with subequal rami (exopod is reduced or very short in Acanthocope), the well developed, 3-articulated mandibular palp (palp of Acanthocope is reduced or small, with straight last article), and pereopods 5-7 dactylus with stout dorsal claw (absent in Acanthocope). Storthyngurinae differ from Eurycopinae Hansen, 1916 (Fig. 2b) in having body spines (absent in Eurycopinae), squama on article 3 of antenna 2 not separated, in the absence of a head rostrum and a medial lobe of antenna 1 article 1 (the lobe prominent in Eurycopinae), and in the presence of the narrow slot for the mandibular articulation with the head. Key to the genera of Storthyngurinae (Figs 1, 3-5) 1 Pereonite 4 anterolateral corners rounded, pereonites 5-7 with 3 dorsal spines each, pleotelson visibly broader than long Microprotus Richardson, 1910 (see diagnosis in Wilson et al. 1989) Pereonite 4 anterolateral corners acute, projecting, pereonites 5-7 with not more than 2 dorsal spines each, pleotelson not broader than long Antenna 1 article 1 with distolateral lobe subrectangular, truncated distally; article 2 longer than the lobe, with proximolateral process. Head frontal margin with shallow rectangular notches for antenna 1 insertion, a pair of anterodorsal tubercles behind these notches Vanhoeffenella gen. n. Antenna 1 article 1 with rounded or triangular distolateral lobe, article 2 without proximolateral process, antennal sockets more or less rounded Antenna 1 article 1 without medial spine, distolateral lobe faintly pronounced, article 2 subequal to or longer than the lobe of article 1, with distomedial process, antenna 2 article 1 without lateral projection, head dorsally domeshaped, without dorsal spines. Pleotelson tip truncated or forked... Rectisura gen. n. 3

4 Antenna 1 article 1 with medial spine near insertion of article Head without dorsal spines (pair of tubercles in S. vemae and S. magnispinis). Pleotelson not pointed posteriorly Storthyngura Vanhöffen, 1914 Head with dorsal spines. Pleotelson pointed posteriorly Body strong, of large size (10-50 mm long), with rather short spines. Pereopods 2-4 anterior coxal projection conspicuously longer than posterior, male pleopod 1 distal tip narrow, not extending far beyond distal margin of pleopod 2. Antenna 1 article 2 markedly shorter than distolateral lobe of article 1... Sursumura gen. n. Body fragile, of small size (6-16 mm long), with very long spines. Both coxal spines of pereopods 2-4 long, subequal in length, male pleopod 1 distal part diverging laterally, extending far beyond distal margin of pleopod 2. Antenna 1 article 2 longer than distolateral lobe of article Storthyngurella Malyutina, 1999 Vanhoeffenella gen. n. Diagnosis. Frontal margin of head with shallow, roughly rectangular notches for antenna 1 insertion, a pair of dorsal anterior tubercles behind these notches. Anterolateral corners of pereonite 3 with acute projections, shorter than coxae. Pleotelson terminal process bent downwards. Body with ventromedial keel of rather long spines. Antenna 1 article 1 without medial spine, distolateral lobe subrectangular, truncated distally; article 2 longer than the lobe, with proximolateral process. Mandibular palp sturdy. Medial margin of maxillipedal palp article 2 straight, shorter than that of article 3. Pereopods 3 and 4 considerably longer than pereopod 2; pereopods 5-7 carpi and propodi broad, oval, propodi longer than carpi. Pleopod 2 stylet nearly half of protopod length. Pleopod 3 endopod with numerous distomedial plumose setae, exopod basal article broader than distal article. Pleopod 4 exopod with many plumose setae distally. Description. Body strong, of large size (10-35 mm long), widest at pereonite 5. Head with oblique furrows behind pair of dorsal tubercles, outlined triangular medial area, usually subdivided by transverse, somewhat convex seam; frontal margin slightly ridged, laterally projecting cheeks at mandibular articulation not visible in dorsal view, ventral area around articulating slot moderately swollen; frons short, steep, frontal arch narrow, high, triangular in frontal view, with stout lateral bulges, clypeus thick, long in dorsal and short in frontal view. Pereonite 1 slightly broader than head. Pereonites 1 4 subdivided into 2 parts by transverse groove. Coxae of pereopods 2-4 with proximal longitudinal keel near lateral border of pereonite. Natasoma somewhat longer than anterior body part (head and ambulosoma). Dorsal sutures between pereonites 5-7 well defined, pereonite 6 jutting into pereonite 5 medially by narrow rounded projection, anterior margin of pereonite 5 with small projections, opposite to posterolateral corners of pereonite 4. Pleonite weakly demarcated from pereonite 7 by shallow groove and by suture from pleotelson. Pleotelson subtriangular, tapering, somewhat longer than broad, dorsally divided into central and two lateral convex lobes, anterolateral corners projecting forwards or perpendicular to body axis, posterolateral projections situating on posterior one-third of pleotelson, short transverse dorsal pore at the base of terminal process, ventral preanal ridge well produced. Antenna 1 basal article with subparallel margins, central part thick, swollen dorsally, without medial spine, with low transverse keel beneath the insertion of article 2; article 2 narrow in proximal part with following conspicuous proximolateral process. Article 1 of antenna 2 without spines, articles 1 and 2 fused dorsally, suture between them present only laterally and ventrally. Mandibular incisor process narrow in dorsal and ventral view, with 4 cusps, lacinia mobilis of left mandible subequal to incisor process in length, molar process broadened distally. Maxilla 2 middle and outer endites with 4 spine-like distal setae: two of them long, with short setulae along, two other short, comb-like, with long spinules along; inner lobe with strong, comb-like distal setae. Maxilliped basis convex ventrally, with proximomedial boss, epipod with oblique groove from proximomedial corner to distolateral margin, lateral margin concave, forming acute curved process. Pereopods 5-7 carpus and propodus about twice as long as wide, ventral margins convex. Pereopod 5 with shortest and broadest basis and largest carpus and propodus, pereopod 7 with opposite proportions. Male pleopod 1 slightly narrowing at midlength. Male pleopod 2 protopod with acute projection distomedially, extrinsic musculature occupying longitudinal central part of protopod, its ventral surface convex, endopod inserted in distal third of protopod, exopod with long distal hook. Uropod less than half as long as pleotelson. 4

5 Etymology. The genus is named after E. Vanhöffen, the author of the genus Storthyngura. Species included. See the following key. Except for the two new ones all species are transferred from Storthyngura. Type species. Vanhoeffenella pulchra (Hansen, 1897) comb. n., by present designation. Distribution. Pacific ocean: northwestern Trenches, depth m, southwestern Trenches, depth m, eastern Pacific, depth m; Atlantic ocean: Caribbean region, depth m, southern region, depth m; southern Indian ocean, depth m. Key to species of Vanhoeffenella gen. n. 1 Pleotelson without well pronounced posterolateral and terminal spines, instead there are angular short processes... 2 Pleotelson with well pronounced posterolateral and terminal spines Dorsal pairs of spines and lateral spines of pereonites 5-7 weakly protruding... 3 Dorsal pairs of spines and lateral spines of pereonites 5-7 well protruding Distance between dorsal spines on pereonite 5 longer than spines V. novaezelandiae (Beddard, 1885) comb. n. Dorsal spines of pereonite 5 situated very close to each other Pleotelson rounded posteriorly. Interantennular distance very short... V. georgei sp. n. Pleotelson pointed posteriorly. Interantennular distance about half of antenna 1 basal article width... V. torbeni (George, 1987) comb. n. 5 Pleotelson lateral margin with small, subacute process posteriorly. Head with small medial spine. Lateral spines of pereonite 5 as long as pereonite 5. Preanal process pointed..... V. eltaniae (George & Menzies, 1968) comb. n. Pleotelson lateral margin with minute triangular process on anterior third and two acute projections with insertion inbetween on posterior third; lateral spines of pereonite 5 as long as half of pereonite 5 width. Preanal process with deep notch... V. moskalevi sp. n. 6 Pereonites 5-7 with pair of low longitudinal keels pointed anteriorly... 7 Pereonites 5-7 with pair of long spines at midlength Head with medial spine near posterior margin.. 8 Head without medial spine Pleotelson posterolateral spines directed backwards, margin between posterolateral spines and terminal spine concave V. pulchra (Hansen, 1897) comb. n. Pleotelson posterolateral spines directed forwards, margin between posterolateral and terminal spines straight... V. unicornalis (Menzies & George, 1972) comb. n. 9 Dorsal keels on pereonite 5 meeting anteriorly.... V. myriamae (George & Hinton, 1982) comb. n. Dorsal keels on pereonites 5-7 parallel Pereonite 2 anterolateral corners with minute acute projection V. caribbea (Benedict, 1901) comb. n. Pereonite 2 anterolateral corners rounded in dorsal view Dorsal body spines rather long. Lateral projection of pereonites 5-7 narrow, pereonite 1 without dorsomedial projection V. kermadecensis (Wolff, 1962) comb. n. Dorsal body spines short. Lateral projection of pereonites 5-7 broad, pereonite 1 with dorsomedial projection V. symmetrica (Menzies, 1962) comb. n. 12 Pereonite 1 without medial spine Pereonite 1 with medial spine Pleotelson terminal margin with a pointed process Pleotelson terminal margin rounded V. scotia (George & Menzies, 1968) comb. n. 14 Pleotelson posterolateral spines proximally broad, directed backwards. Antenna 1 article 1 with small spine-like seta near insertion of article 2... V. gordonae (Wolff, 1962) comb. n. Pleotelson posterolateral spines narrow. Antenna 1 article 1 without small spine-like seta near insertion of article Pleotelson posterolateral spines very slender and strongly curved forwards, propodi of pereopods 1 and 5 relatively long, pleotelson terminal spine almost straight for entire length V. challengeri (Wolff, 1962) comb. n. Pleotelson posterolateral spines relatively broad at base, slightly curved forwards, propodi of pereopods 1 and 5 relatively short, pleotelson terminal spine apical part steeply bent downwards V. fragilis (Beddard, 1885) comb. n. 5

6 16 Head with pair of long spines on low cones behind antenna 1. Pleotelson terminal spine short in dorsal view, posterolateral processes close to apex V. bicornis (Birstein, 1957) comb. n. Head without spines Pleotelson terminal spine long, acute, "resembling the outer part of an ordinary fountain-pen" (Wolff 1962) V. chelata (Birstein, 1957) comb. n. Terminal process broad, rounded in dorsal view V. birsteini (Menzies, 1962) comb. n. Vanhoeffenella georgei sp. n. (Figs 6-14) Material examined. Holotype male 24.2 mm (ZMMU Mc 1379): RV Dmitriy Mendeleev, cruise 43, , St. 4107, S, W, depth m. Paratypes: 2 males 18.2 mm and 16.2 mm, 1 female 25 mm from type locality (ZMMU Mc 1380); 1 male 21.3 mm, 2 females 22.5 mm and 16.2 mm long, 4 juvenile specimens from St. 4109, S, W, depth 5225 m (ZMMU Mc 1381). Description of male holotype. Body (Figs 6a, b) 2.1 times as long as wide, 0.25 times as high as long, dorsal surface finely granulated, without setae. Head shorter laterally than medially from point between antennae to posterior margin, this distance 0.35 times as long as head wide. Interantennular gap very short, bases of antennae 1 almost meeting at middle. Frons from point between antennae 1 to clypeus 0.17 times as long as head totally. Clypeus (Figs 6c, d) 1.6 times as wide as labrum, thick, 0.5 times in dorsal view and 0.3 in frontal view as long medially as labrum. Pereonite 1 without dorsal spine, conspicuously shorter than each of subequal pereonites 2-4. Dorsomedial spine of pereonites 2 4 as long as pereonite, very narrow in dorsal view and broad in lateral view. Acute anterolateral projections of pereonites 3 and 4 half as long as corresponding coxae in dorsal view. Coxae of pereopods 1 4 short, pointed anterolaterally, without spines. Pereonite 5 anterior margin with pair of short dorsal spines directed forward, meeting medially in one point; following pereonites with pair of low dorsal longitudinal keels, distance between them greater than that between spines of pereonite 5. Lateral margins of pereonite 5 slightly concave, those of pereonites 6 and 7 convex; anterolateral acute corners of pereonite 5 somewhat longer and narrower than those of pereonites 6 and 7, all of them not projecting over natasoma outline. Pleonite 0.65 times as long as following convex anterior part of pleotelson. Pleotelson as long as wide, posterior margin rounded, minute terminal and posterolateral processes hardly visible only laterally and ventrally; preanal ventral process rather short, rounded. Lateral margins of pereonites and pleotelson smooth, without setae. Antenna 1 (Fig. 9) 0.6 times as long as body; article times as long as wide basally, central part 0.7 times as thick as wide, distolateral lobe 0.4 times as long and 0.7 as wide as article; Article 2 almost half as long as article 1, with conspicuous proximolateral process and distomedial acute projection; articles , 0.4, and 0.45 times as long as article 2 respectively; flagellar articles numerous, very short, with small aesthetascs. Antenna 2 (Fig. 6c) broken, only 4 basal articles present. Article 3 narrower and shorter laterally than article 2, with short distal triangular processes. Mandibles (Fig. 7) incisor process with 4 cusps, lacinia mobilis of left mandible with 5 teeth, spine row with 21 and 22 members in left and right mandibles respectively; palp slightly longer (1.1) than mandibular body, article 2 somewhat curved, narrowing in midline, 4 times as long as wide, 1.8 times as long as article 1, with 3 rather stout distal setae, article 3 relatively narrow. Maxilla 1 (Fig. 8) outer endite twice as wide as inner one, inner endite tapering distally. Maxilla 2 (Fig. 8) inner endite shortest, with 9-10 serrated stout setae distally. Maxilliped (Fig. 9) endite with 14 broad coupling hooks, distal margin concave, with 9-10 fan-setae and numerous thin setae, endite 0.6 times as wide as basis, palp 1.1 times as wide as basis; article 2 lateral length subequal to article width; article times as long as article 2 laterally and 1.4 times medially, article 4 medial lobe about half as long as article 5, both with tuft of distal setae. Epipod acute distally, 2.6 times as long as wide, lateral acute projection situating on the midddle of lateral length, lateral margin with small setae. Pereopod bases gradually decreasing in length and broadening from 1 to 5 and then increasing and narrowing to the longest basis of P7 (length/width ratios are 4.5, 3.7, 2.7, 2.3, 2.15, 3.3, 4.0 respectively). All bases with row of small spines and plumose setae on dorsal margin. Pereopod 1 (Fig. 10) about half as long as body; ischium about half as long as basis, both articles with sparse thin setae; merus 0.25 times as long as basis; carpus longest, 1.1 times as long as basis, 6

7 slightly curved; propodus 0.7 as long and about half as wide as carpus, both articles with ventral transparent fringe and small setae; dactylus half as long as merus. Pereopod 2 (Fig. 11) carpus twice as long as basis, propodus longest, 1.1 times as long as carpus, both articles as wide as the same articles in pereopod 1, dactylus twice as long as merus. Pereopods 3-4 missing, only bases present (Fig. 11). Pereopods 5-7 (Figs 10, 12) slightly longer than pereopod 1, length/width ratios of carpi 5-7 are 1.8, 1.7, 1.7 respectively; propodi length/width ratios are 2.5, 2.45, 2.4; propodi length/carpi length 1.32, 1.30, 1.22; dactyli 5 7 only slightly longer than meri, with numerous thin, simple dorsal setae, dorsal claw with acute inner projection near tip. Pleopod 1 (Fig. 13) 2.5 times as long as wide proximally, proximal half with longitudinal rounded keels; midlength waist half as wide as proximal part, distal half broadening, last distal part (0.1 of total pleopod length) narrower than waist, with dense row of small setae ventrally; distal margin of inner lobes rounded, outer lobes narrow, acute. Pleopod 2 (Fig. 14) protopod 1.4 times as long as wide, area with musculature bulging, convex ventrally, endopod inserted after 0.7 of protopod length from basal margin, stylet 0.45 times as long as protopod, with short tapering tip, not extending beyond distal margin of protopod. Pleopod 3 (Fig. 13) endopod rounded, with numerous (~ 60) distolateral plumose setae, twice as long as wide and 0.7 times as long as pleopod 2; exopod 1.3 times as long as endopod, 2-segmented, proximal article 0.25 as wide as endopod, distal article 0.7 as long and 0.5 as wide as proximal one, with 16 distal plumose setae and row of thin simple lateral setae. Pleopod 4 (Fig. 11) endopod semicircular, with 17 plumose setae on distomedial tip, exopod 1.1 times as long and 0.5 wide as endopod, with 18 distal plumose setae, lateral and medial margins with dense row of fine setae. Pleopod 5 (Fig. 8) of one broad lobe bent upwards laterally and covering lateral parts of pleopods 3 and 4, distal margin with 10 setae. Uropod (Fig. 6f) 0.45 as long as pleotelson; protopod slightly broadening distally, with 2 distal setae, 2.6 as long as wide; endopod about half as wide and 1.1 times as long as protopod, with 3 strong unequal bifid and a few simple distal setae; exopod half as wide and 0.6 times as long as endopod, with two bifid distal setae. Female paratype similar to male. Differences are the following: in females lateral length of head subequal to medial length from point between antennae to posterior margin. Antenna 1 shorter than in male, with articles 3 5 slightly narrower, articles of flagellum more elongate. Bases of pereopods 3 and 4 more slender and shorter than in male. Operculum (Fig. 14) oval, 1.3 times as long as wide. Keel covered with small acute tubercules, distal part elevated. Etymology. The species is named after the American isopodologist, Prof. Robert Y. George, who described many species of Storthyngura, in particular the very similar S. torbeni. Remarks. The new species belongs to the group V. novaezelandiae, which includes in addition to this species and V. moskalevi sp. n. the species V. torbeni (George, 1987) from the Puerto-Rico Trench and V. eltaniae (George & Menzies, 1968) from the South- Sandwich Trench. The group is characterized by the triangular-rounded shape of the pleotelson, with posterolateral projections almost invisible from above. V. georgei sp. n. is most similar to V. torbeni (Figs 15-20). The two species share the same arrangement of dorsal spines on pereonites, and the shape of the pleotelson. V. georgei sp. n. can be distinguished by a more rounded pleotelson, a smaller interantennular gap, longer coxae of pereopod 1, rounder lateral margins of distal half of pleopod 1, and a stouter protopod of uropod (length/width ratio is 3 in V. georgei sp. n., about 5 in V. torbeni). V. georgei sp. n. is also very similar to V. novaezelandiae (Beddard, 1885), (see Wolff 1962: pl. IV G-H, text-figs 66-68). All three species have a natasoma outline similar to the one seen in species of Eurycope. From V. novaezelandiae, V. georgei sp. n. is distinguished by the more elongate pleotelson, the closer position of the dorsomedial spines on the anterior margin of pereonite 5, and V. georgei sp. n. has the distal rounded part of pleopod 1 longer than that of V. novaezelandicae. Distribution. Southern Atlantic ocean: Argentina Basin, at depths of m. Vanhoeffenella torbeni (George, 1987) (Figs 15-20) Storthyngura torbeni George, 1987: , figs 1-2. Material examined. 27 males, 12 females, specimens from the Zoological Museum, University of Copenhagen: RV Akademik Kurchatov, cruise 7

8 14, , St. 1182, S, W, depth 6400 m, trawl Sigsby. Remarks. Some details not illustrated or not clear in the original description are presented in Figs Distribution. Atlantic ocean: Puerto Rico Trench, at depths of m. Vanhoeffenella moskalevi sp. n. (Figs 21-29) Material examined. Holotype female 28.2 mm (ZMMU Mc 1382): RV Akademik Kurchatov, cruise 11, , St. 896, S, W, depth m, trawl Sigsby. Paratypes (ZMMU Mc 1383): 1 damaged male about 33 mm, 1 natasoma of a female 14 mm, 1 female 17 mm without head and pleotelson, all from type locality. Description of female holotype. Body (Fig. 21) 3.2 times as long as pereonite 5 wide, if measured without lateral projections, 0.2 times as high as long, dorsal surface of body fine granulated, without setae. Head medially 0.4 times as long as wide, lateral length subequal to medial length, interantennular distance 0.25 as wide as antenna 1 article 1, frons 0.23 times as long as head totally; clypeus 1.6 times as wide as labrum, medially in dorsal view 0.5 times and 0.3 times in frontal viewas long as labrum. Pereonite 1 only slightly shorter than pereonite 4, pereonites 2 and 3 subequal in length. Pereonite 1 without dorsal spine, dorsomedial spine of pereonites 2 4 each subequal to pereonite in length, narrow in dorsal view and with broad base. Pereonites 3 and 4 anterolateral projections acute, about half as long as coxal spines of corresponding pereopods. Pereopods 1 4 coxal anterior spine almost as long as pereonite laterally. Natasoma 1.5 times as long as anterior body part. Pereonites 5-7 with pair of dorsal spines directed forward, distance between spines subequal for all three pereonites. Frontal margin of pereonite 5 bearing laterally protuberances that overlap by caudal margin of pereonite 4; anterolateral corners projecting in long spines 2.5 times as long as pereonite. Anterolateral spines of following pereonites and pleotelson gradually shortening; pleonite 0.65 times as long as following convex anterior part of pleotelson. Pleotelson as long as wide, lateral margins flattened, raised upwards, on anterior third pair of small triangular processes, posterior third with two angular projections with incision inbetween, posterior process rectangular, tapering. Preanal ventral process of pleotelson long, tip furcate, with rounded notch. Lateral margins of pereonites and pleotelson smooth, without setae. Antenna 1 (not illustrated separately) very similar to that of male (see description of male, Fig 27), but slightly shorter, with articles 2 5 somewhat narrower, flagellar articles slightly longer than in male. Antenna 2 (Fig. 21) broken, only 4 basal articles present. Articles 2-4 subequal in lateral length, article 3 conspicuously longer than article 2 medially. Mandibles (Figs 22, 23) incisor process with 4 cusps, lacinia mobilis of left mandible subequal in length to incisor process, with 5 teeth, spine row with 27 and 28 members in left and right mandibles respectively; palp subequal in length to mandibular body, article 1 slightly flattened, article 2 subcylindrical, somewhat curved, narrowing in midline, about 4 times as long as wide, twice as long as article 1, with 3 rather stout distal setae. Maxilla 1 (Fig. 24) outer endite 2.3 times as wide as inner endite. Maxilla 2 (Fig. 24) middle endite shortest, outer endite longest. Spine-like setae of middle and outer endites relatively short. Maxilliped (Fig. 24) endite with 16 coupling hooks, endite distal margin denticulated, with 9-10 narrow fan setae and numerous thin setae, endite 0.7 times as wide as basis, palp 1.2 times as wide as basis; article 2 laterally 1.4 times as long as medially and 0.9 as long as wide; article times as long as article 2 laterally and 1.4 times medially; article 4 visibly longer laterally than article 3 and article 5, article 4 medial lobe 0.6 as long as article 5, both with tuft of distal setae. Epipod 2.3 times as long as wide, distal corner rounded, lateral projection situated on 0.6 of lateral length from proximal margin. Pereopods 1-7 bases length/width ratios are 4.76, 4.3, 4.0, 3.2, 1.8, 2.9, 3.9, respectively. Pereopod 1 (Fig. 25) only three articles present: ischium half as long as basis, both articles with sparse thin setae; merus about 0.25 as long as basis. Pereopods 2-4 missing, only bases present (Fig. 25). Pereopods 5-7 (Figs 25, 26): carpi 5-7 length/width ratios are 1.75, 1.8, 1.8, respectively; propodi length/width ratios are 2.8, 2.6, 2.7; propodi conspicuously longer (about 1.4 times) than carpi; dactyli 5 7 slightly longer than meri. Operculum (Fig. 21d) as long as wide, distal part elevated, lateral and distal margins with plumose setae. Keel with spine in the end of proximal onethird, directed backwards. 8

9 Pleopod 3 (Fig. 29) endopod 1.4 times as long as wide and 0.7 times as long as pleopod 2, with numerous (about 40) distolateral short plumose setae, exopod 1.6 times as long as endopod, 2- segmented, proximal article 0.3 times as wide as endopod, almost 3 times as wide and 1.4 times as long as distal article, the later bearing about 30 distal plumose setae. Pleopod 4 (Fig. 29) endopod without setae, exopod as long and 0.4 times as wide as endopod, with about 20 distal plumose setae. Pleopod 5 (Fig. 29) of one broad lobe without setae, bent upwards laterally and covering lateral parts of pleopods 3 and 4. Uropod (Fig. 25) 0.3 times as long as pleotelson; protopod slightly broadening distally, with a few distal setae, 3.3 times as long as wide distally and 5.5 times as wide proximally; endopod as long and about half as wide as protopod, with 8 strong unequal bifid setae distally; exopod 0.7 times as long and as wide as endopod, with 3 bifid setae distally. Description of male paratype. Differences to the female are: Antenna 1 (Fig. 27) 0.6 times as long as body, article times as long as wide basally, and 2.1 times as long as wide on middle part, article thickness 0.8 of central part width, distolateral lobe obliquely truncated distally, 0.4 as long as article; article 2 half as long as article 1 and 1.2 times as long as article 1 lobe, distomedial acute projection conspicuous, with small seta, small proximolateral process feebly projecting; articles , 0.2, and 0.3 times as long as article 2 respectively, flagellum of numerous very short articles with aesthetascs. Pleopod 1 (Fig. 27) 2.5 times as long as wide proximally, midlength waist 0.4 times as wide as proximal part, broadening distal half 1.6 times as wide as waist, last distal narrow part 1.2 times as wide as waist, with dense row of small setae ventrally, distal margin of inner lobes rounded, outer lobes narrow, directed laterally. Pleopod 2 (Fig. 28) protopod 1.5 times as long as wide, acute distomedial angle slightly projecting, endopod inserted after 0.75 of protopod length from basal margin, stylet 0.45 times as long as protopod, with short tapering tip. Etymology. The species is named after the marine biologist, Dr. L. Moskalev, from the Shirshov Institute of Oceanology, Moscow, who collected most of the material used in this work. Remarks. In spite of its long anterolateral spines of pereonite 5 the new species can be assigned to the group V. novaezelandiae because its pleotelson has a smooth outline. V. moskalevi sp. n. is most similar to V. eltaniae (George & Menzies, 1968) from the South-Sandwich Trench (Figs 30-37). The two species share a similar shape of the natasoma, the arrangement of dorsal spines on pereonites 6-7, a frontal margin of pereonite 5 laterally limited by thick protuberances, and a male pleopod 2 tapering distally. From V. eltaniae, V. moskalevi sp. n. is distinguished by the lack of dorsal spines on the head and pereonite 1, longer anterolateral processes of pereonite 5, incised lateral margins of the pleotelson, a furcate tip of the preanal process, a broader maxillipedal palp, distal parts of male pleopod 1 directed outwards, and a less protruding mediodistal angle of the male pleopod 2 protopod. Distribution. Atlantic ocean: South-Sandwich Trench, at depths of m. Vanhoeffenella eltaniae (George & Menzies, 1968) comb. n. (Figs 30-37) Storthyngura eltaniae George & Menzies, 1968: 289, fig. 8. Material examined. 2 females 26.5 and 27.5 mm long; one male 21.4 mm long and a strongly damaged male: RV Akademik Kurchatov, cruise 11, , St. 896, S, W, depth m, trawl Sigsby; 2 males 17 and 12.2 mm long and immature female 7.5 mm long: St. 898, S, W, depth m. Remarks. The females from St. 896 show no differences except that one of them has a small dorsomedial spine on pereonite 1 lacking in another one, as in the male from the same station. The morphology is depicted in Figs Distribution. Atlantic ocean: South-Sandwich Trench, at depths of m. Vanhoeffenella myriamae (George & Hinton, 1982) comb. n. (Figs 38-43) Storthyngura myriamae George & Hinton, 1982: 93-98, fig. 1. Material examined. female, 17.5 mm long and 8 mm wide: RV Akademik Kurchatov, cruise 43, St. 4900, S, W, m; 1 immature female 16.4 mm long, St. 4905, S, W, depth 4725 m. Female 16.4 mm long, German expedition DIVA 1 RV Meteor, cruise 48/1, , St. 333, S, E, depth 9

10 5426 m; 1 female 21.5 mm long, St. 339, S, E, depth 5395 m. Remarks. V. myriamae belongs to the «pulchra» group, which until now includes 6 species. Wolff (1962) studied in detail the types of Storthyngura pulchra Hansen, 1897 from the Eastern Pacific and of S. caribbea (Benedict, 1901) from the Caribbean Basin. He united these species with his new S. kermadecensis from the Kermadec Trench (off New Zealand) as three subspecies of S. pulchra. After this revision three other very similar species were described: S. symmetrica Menzies, 1962 from the South-Eastern Atlantic, S. unicornalis Menzies & George, 1972 from the Peru-Chile Trench, and S. myriamae George & Hinton, 1982 from the Angola Basin. These six species share similar longitudinal sharp keels on pereonites 5-7, similar concave lateral margins of natasomal pereonites, with rounded, projecting posterolateral corners, and very similar details of all appendages. All these species are very alike and following Wolff s logic (1962) all of them could be placed as subspecies of V. pulchra. Unfortunately, in all these cases we have only type material represented by one or a few specimens. V. unicornalis and V. symmetrica, for example, were described from immature specimens, and without new material it is difficult to say anything definite about the validity of these species. But the geographical distance of type localities (see more detailed distribution data of Storthyngura species in Brandt & Malyutina 2002) and some morphological distinctions (Figs 1d, and the above key for Vanhoeffenella) allow one to consider them all as separate species. To the differences noted by the authors, comparing V. myriamae and S. caribbea I would like to add the different direction of the dorsal keels on pereonite 5. In contrast to V. myriamae they diverge in all other species of the «pulchra» group. The presence of an unusual long basal article of the maxillipedal palp, shown by George & Hinton for V. myriamae and noted as an apomorphy for this species, was not confirmed after the study of the holotype and the specimens from our material (Fig. 40). Distribution. Atlantic ocean: Angola Basin, at depths of m, southern part of Brazilian Basin, at depths of m. Vanhoeffenella caribbea (Benedict, 1901) comb. n. (Figs 44-47) Eurycope caribbea Benedict in Richardson, 1901: 559, fig. 29. Richardson (1905: 493, fig. 548). Storthyngura caribbea (Benedict, 1901). Vanhöffen (1914: 584), Hansen (1916: 132). Storthyngura pulchra (Hansen, 1897). Wolff (1956: 116). Storthyngura pulchra caribbea (Benedict, 1901). Wolff (1962: 138, pls VI F, VII E-F, VIII D; textfigs 79f-g, 80g-j, 81f). Material examined. 4 type specimens, including the male lectotype selected by T. Wolff (USNM 23911): RV Albatross, voyage , St. 2751, off Windward Is. in West Indies, depth 1260 m. Distribution. Atlantic ocean: off Windward Is. in West Indies, at a depth of 1260 m. Vanhoeffenella unicornalis (Menzies & George, 1972) comb. n. (Figs 48-51) Storthyngura unicornalis Menzies & George, 1972: 9.55, fig. 37. Material examined. Female 12 mm long, holotype (USNM No ): RV Anton Bruun , S, W, depth m. Remarks. In describing this species the authors compared it only with V. caribbea, but the most similar species is V. pulchra which also has a dorsomedial spine on its head and differs from V. unicornalis mainly by a different shape of the posterolateral margins of the pleotelson (Fig. 1d). Distribution. Pacific ocean: Peru-Chile Trench, at depths of m Vanhoeffenella symmetrica (Menzies, 1962) comb. n. (Figs 52-53) Storthyngura symmetrica Menzies, 1962: 149, fig. 38F-I. Material examined. Immature male 6.7 mm long, holotype (AMNH No 12099): RV Vema , S, E, depth 4893 m. Distribution. Southeastern Atlantic, at a depth of 4893 m. 10

11 Vanhoeffenella chelata (Birstein, 1957) comb. n. (Figs 54-55) Storthyngura chelata Birstein, 1957: 962, Figs 1A, 2. Wolff (1962: 133, Pl.VI B-C; text-fig. 78), Birstein (1963: 117), Birstein (1970: 335). Material examined. Male 31 mm long, lectotype: RV Vitjaz, St. 2144, N, E, depth 6860 m. Remarks. The types of V. chelata and V. bicornis Birstein, 1957 (Figs 56, 57) are redrawn because Wolff (1962), comparing them with V. pulchra, noted that V. bicornis is the most similar species to the pulchra group. In my opinion, V. chelata much more resembles the members of the «pulchra» group mainly by the similar shape of the pleotelson. V. chelata has longer and more acute projections of the body and an unusual projecting distal part of the male pleopod 1. But as correctly noted by Wolff ( how little taxonomic significance can be applied to the length, shape and direction of spines ), the general shape of the body and its main parts, for example, the pleotelson, are more stable and therefore more important features. Distribution. Northwestern Pacific Trenches, at depths of m. Vanhoeffenella bicornis (Birstein, 1957) comb. n. (Figs 56-57) Storthyngura bicornis Birstein, 1957: 965, figs 1B, 3. Wolff (1962: 133, Pl.VI B-C), Birstein (1963: 117). Material examined. Male 23 mm long, lectotype: RV Vitjaz, St. 3214, N, E, depth m. Distribution. Northwestern Pacific Trenches, at depths of m. Vanhoeffenella scotia (George & Menzies, 1968) comb. n. (Figs 58-59) Storthyngura scotia George & Menzies, 1968a: 284, figs 5,6. Material examined. About 30 specimens, many fragments: RV Dmitriy Mendeleev, cruise 43, , St. 4097, S, W, depth m; one immature female 6 mm long: , St. 4094, 60 42' S W, depth m. Distribution. Atlantic ocean: Scotia Sea, at depths of m. Vanhoeffenella birsteini (Menzies, 1962) comb. n. (Figs 59-60) Storthyngura birsteini Menzies, 1962: 149, fig.40a- B. George & Menzies (1968a: 294, fig. 11). Material examined. Female, 22.5 mm long and 9.6 mm wide with empty brood pouch, female with oostegites, without pleotelson, posterior parts of 2 males and one females: RV Akademik Kurchatov, cruise 11, , St. 926, S, W, depth m, trawl Sigsby, 1.5 m. Remarks. Opercula of females with spine on ventral keel. Distribution. Atlantic ocean: Drake Passage, at depths of m, South-Sandwich Trench, at depths of m. Sursumura gen. n. Diagnosis. Head dorsally with pair of spines at midlength, behind lateral margins of antennae 1. Anterolateral corners of pereonite 3 rounded; body without ventromedial spines, pleotelson tip acute, bent upwards. Antenna 1 article 1 with medial spine, distolateral lobe long, tongue-like; article 2 shorter than article 1 lobe, with distomedial projection. Antenna 2 article 1 well separated from article 2, with lateral spine. Mandible palp narrow. Maxilliped palp article 2 medial margin longer than article 3, epipod lateral margin without acute projection. Pereopods 5-7 carpi and especially propodi relatively narrow, more than three times as long as wide. Male pleopod 1 with definite waist at midlength, male pleopod 2 stylet about half of protopod length, exopod short. Pleopod 4 exopod with one or a few plumose setae. Description. Body strong, of large size (till 49 mm, smallest known species 9.7 mm long). Dorsal head spines on low elevations, frontal margin forming a ridge. Frons short, steep, frontal arch low, triangular in frontal view, with stout lateral bulges and medial rounded projection, clypeus dorsally longer than frontally. Ventral areas above and under slot for mandibular articulation considerably swollen, these cheeks visible in dorsal view. Pereonites 1-4 with dorsomedial spine each, tergite subdivided into 2 parts by transverse groove. Dorsal surface of natasoma granulated, rugged, with tubercles and setae. Dorsal sutures between pereonites 5-7 visible 11

12 at least on lateral portions, each pereonite with pair of dorsal spines and anterolateral acute projection. Pleotelson longer than broad dorsally, subdivided into two parts: a large subrectangular anterior and a small triangular posterior part, anterolateral corners rounded (or acute in S. robustissima), anterolateral projection on lateral margin directed outwards, posterolateral projections situated on posterior third of pleotelson. Usually one or two dorsomedial spines along and a pair of minute spines dorsally near midlength. Terminal process acute, somewhat bent upwards, with small point of dorsal pore at the base, preanal ridge feebly protruding. Incisor process of mandible broad in dorsal and ventral view, and narrow in frontal and medial view. Pereopod 1 dactylar dorsal claw tapering distally. Pereopods 3 and 4 conspicuously longer than pereopod 2. Pereopods 5-7 carpus and propodus elongated, oval, propodi subequal to carpi. Male pleopod 2 exopod short. Pleopod 3 endopod with a few and exopod with numerous plumose setae. Both articles of pleopod 3 exopod subequal in width. Etymology. From Latin sursum, meaning upward, referring to the upward-bent tail. Species included. See the following key. Except for the new ones all species are transferred from Storthyngura. Type species. Sursumura praegrandis (George & Menzies, 1968), by present designation. Distribution. Southern hemisphere: one species collected in the Bellinsgausen Sea, at a depth of 400 m, and one in the Tasman Sea, at 4400 m; the remaining species occur the South Antil region, depth range is m. Key to species of Sursumura gen. n. 1 Pleotelson terminal process acute. Pereonites 1-4 with one dorsomedial spine... 2 Pleotelson terminal process furcate. Pereonites 1-4 with 3 dorsal spines each S. magnifica (Chardy, 1976) comb. n. (tentative placement) 2 Pleotelson posterolateral processes directed outwards or forwards. Body spines relatively long... 3 Pleotelson posterolateral processes directed backwards. Body spines relatively short S. aberrata sp. n. 3 Pleotelson anterolateral corners and lateral margin in front of posterolateral process acute.. 4 Pleotelson anterolateral corners and lateral margin in front of posterolateral process rounded Pleotelson visibly longer than wide. Dorsum of body finely granulate, without setae S. robustissima (Monod, 1925) comb. n. Pleotelson 0.9 as long as wide. Dorsum with spine-like tubercles and dense hair-like setules... S. spinosissima (Brandt, 2002) comb. n. 5 Pleonite without dorsomedial spine... 6 Pleonite with dorsomedial spine Pleotelson posterolateral processes directed outwards. Antenna 2 article 1 with lateral spine S. abyssalis (Wolff, 1962) comb. n. Pleotelson posterolateral processes directed backwards. Antenna 2 article 1 without lateral spine... S. atlantica (Beddard, 1885) comb. n. 7 Pleotelson relatively short, about as long as wide, lateral margin between lateral processes almost not projecting... S. argentica (George & Menzies, 1968) comb. n. Pleotelson relatively long, conspicuously longer than wide, lateral margin between lateral processes projecting Pleotelson anterolateral angles acute (about 30 ). Pereonite 5 with pair of dorsal spines... S. praegrandis (George & Menzies, 1968) comb. n. Pleotelson anterolateral angles wide, almost rectangular. Pereonite 5 with 3 dorsal spines S. falcata (George & Menzies, 1968) comb. n. Sursumura aberrata sp. n. (Figs 61-68) Material examined. Holotype female 24.2 mm (ZMMU Mc 1384): RV Akademik Kurchatov, cruise 11, St. 864, S, W, m. Paratype female 25 mm (ZMMU Mc 1385), from type locality. Description of female. Body (Figs 61, 62) about 2.7 times as long as pereonite 5 wide, dorsal surface very finely granulate, spines with short setae. Head medially from point between antennae to posterior margin 0.3 times as long as wide, distance between bases of antennae 0.25 as wide as antenna 1 basally. Frons depressed, sloping, 0.25 as long as head totally, lateral bulges diverging with angle of about 90º, frontal arch short, clypeus 1.6 times as wide as labrum, medially 0.6 times in dorsal view and 0.3 times in frontal view as long as labrum. Pereonite 1 slightly shorter than each of subequal pereonites 2-4; pereonites 1 4 with dorsomedial spine each, quite 12

13 sturdy, slightly shorter than pereonite. Anterolateral projections of pereonite 4 acute, directed outwards, almost half as long as coxal spine; coxae of pereopods 1 4 with thin spines. Natasoma about 1.5 times as long as anterior body part. Pereonites 5-7 fused dorsomedially, without sutures, each pereonite with pair of short dorsal spines, distance between spines similar in all pairs; anterolateral corners of pereonites 5-7 similar in shape and size, short, subrectangular. Pleonite short, fully fused with pereonite 7 and separated from pleotelson by suture. Pleotelson 1.1 times as long as wide, having original shape for genus: anterolateral rounded corners short, broad, directed outwards, margin behind them straight; posterolateral processes acute, half as wide as anterolateral ones, directed backwards; terminal projection caudally from insertion of uropods 0.23 times as long as pleotelson, rounded, with short acute tip; preanal ventral process short, rounded; dorsum with 2 medial blunt spines: posterior spine smaller than anterior one, a pair of minute tubercles behind the posterior spine. Lateral processes of pereonites 5-7, pleotelson and terminal process of pleotelson flattened and slightly bent upwards; body lateral margins serrated, without setae. Antenna 1 (Fig. 63) about 0.3 times as long as body, article 1 two times as long as wide basally and 2.4 times as central part wide, central part almost as thick as wide, with 2 small dorsal setae, medial spine narrow, subequal in length to distolateral lobe. Article times as long as article 1, conspicuously shorter than lateral lobe of article 1, distal width together with distomedial process 0.4 of article 1 central width; article 3 elongate, with few small setae along medial margin, articles , 0.3, and 0.7 times as long as article 2 respectively, flagellum of 23 short articles. Antenna 2 (Fig. 63) broken, only 4 basal articles present. Article 1 with lateral spine shorter than article, article 2 distal margin slightly serrated, article 3 dorsally almost twice as long as article 2, distolateral spine longer than distomedial one. Mandibles (Fig. 64) incisor process with 2 distinct and 2 weak teeth; lacinia mobilis of left mandible slender, shorter than incisor process, with 3 distal teeth and basal boss, spine row with 16 and 19 members in left and right mandibles, respectively; molar process tapering, obliquely truncated; proximoventral part of mandibular body with acute keel, proximal narrow acute projection well separated from mandibular body. Palp slightly shorter (0.9) than mandibular body, article 2 somewhat curved, 7.5 times as long as wide, 3.3 times as long as article 1, with 3 stout acute setae, article 3 relatively narrow. Maxilla 1 (Fig. 65) outer endite twice as wide as inner one. Maxilla 2 (Fig. 65) inner endite subequal in length to central endite, with 7 sturdy comb-like and many simple distal setae and long thin medial setae, central endite with additional short stout finger-like setae. Maxilliped (Fig. 66) endite with 11 coupling hooks, distal margin serrated, with 9-10 fan-setae and numerous thin simple setae; palp article 2 medial margin slightly concave, 1.2 times as long as that of article 3, article 4 longer than article 5 laterally, distomedial lobe of article 4 and article 5 with tuft of long setulated setae. Epipod rounded distally, 3 times as long as wide. Bases of pereopods (Figs 61b, c; 62c) subequal in length, broadening from 1 to 4 and then slightly narrowing to 7, length/width ratios are 9.5, 5.3, 4.4, 4.6, 5.7, 6.1, 5.8, respectively. Pereopod 1 (Fig. 67) 0.4 times as long as body, all articles with sparse small marginal setae; basis longest, ischium 0.4 times, merus 0.2 times as long as basis, carpus 0.85 times as long as basis, only slightly curved; propodus 0.6 times as long and as wide as carpus, both articles about 12 times as long as wide; dactylus almost half as long as merus. Pereopods 2-6 missing, only basis present. Pereopod 7 (Fig. 67) 1.4 times as long as pereopod 1, ischium 0.6 as long as basis; carpus almost as long and 1.5 times as wide as basis, 3.3 times as long as wide, ventral margin straight, dorsal margin somewhat convex; propodus as long and as wide as basis, 5.5 times as long as wide, propodus and carpus with short, thin plumose marginal setae; dactylus half as long as propodus, with numerous thin, simple dorsal setae, claws damaged. Pleopod 2 (Fig. 62b) almost as long as wide, margins with row of short plumose setae, ventromedial keel rounded, granulated, basal part with small acute process. Pleopod 3 (Fig. 68) endopod rounded, about twice as long as wide, with 3 or 4 distal plumose setae, exopod slightly longer than endopod, with row of thin simple lateral setae, basal article 0.25 times as wide as endopod, distal article slightly narrower and 0.45 as long as proximal article, with 8 distal plumose setae. Pleopod 4 (Fig. 68) endopod subequal in size to that of pleopod 3, exopod about half as wide and 0.85 times as long as endopod, with 1 distal plumose seta. 13

14 Pleopod 5 (Fig. 68) one lobe slightly larger than pleopods 4 and 3. Uropod (Fig. 68) 0.6 times as long as pleotelson; protopod distally almost twice as wide as proximally, with few distal unequal bifid setae, 2.9 times as long as wide distally and 5 times proximally; exopod about 0.3 times as wide and 0.8 times as long as protopod, with 2 distal setae; endopod missing. Male unknown. Etymology. From Latin aberratus, meaning unusual. Remarks. Sursumura aberrata sp. n. is distinguished from all other species of Sursumura by the unusual shape of the pleotelson and the anterolateral projections of pereonites 5-7, which are short, rectangular, and not projected anteriorly as in the other species of Sursumura. Distribution. Southern Atlantic ocean: South- Sandwich Trench, at depths of m. Sursumura praegrandis (George & Menzies, 1968) comb. n. (Figs 69-70) Storthyngura praegrandis George & Menzies, 1968: 291, figs 9, 10. Material examined. One female, 16 mm long, one male 17 mm long: RV Akademik Kurchatov, cruise 11, , St. 908, S, W, depth m.; one female approximately 20 mm long: , St. 916, 'S 'W, depth m.; one female 29 mm long: , St. 927, 52 40' S 'W, depth m.; one female 21 mm long: St. 928, 52 15' S 56 51'W, depth 1105 m; one female 37 mm long, 2 males 33.4 mm and 27.8 mm long: RV Dmitriy Mendeleev cruise 43, , St. 4093, 60 43' S 41 14'W, depth m. Distribution. South Atlantic: Drake Passage, Scotia Sea, at depths of m. Rectisura gen. n. Diagnosis. Head domed dorsally, without spines, frons steep. Anterolateral corners of pereonite 3 without projections. Pereonites 5-7 with dorsal sutures, pleotelson tip rather broad, truncate or concave. Antenna 1 article 1 without medial spine, distolateral lobe rounded, weakly pronounced; article 2 length subequal to lobe or slightly longer, with distomedial process. Antenna 2 article 1 without lateral projection. Mandibular palp thin. Medial margin of maxilliped palp article 2 not shorter than that of article 3, article 3 conspicuously narrower than article 2, lateral margin of epipod with acute projection. Male pleopod 1 elongate, distal one-fourth bulbous. Male pleopod 2 exopod short, thick; stylet of endopod short, less than one third of protopod length. Pleopod 4 exopod with one or a few plumose setae. Description. Body strong, elongate, widest at pereonite 5. Head dorsally with longitudinal low convexities like in a garlic bulb. Frontal margin slightly ridged, with broad rounded antennal sockets. Laterally projecting cheeks at mandibular articulation point visible dorsally, ventral area around articulation slot swollen; frontal arch perpendicular to frons, low, narrow, triangular in frontal view, with stout lateral bulges, clypeus long in dorsal and short in frontal view. Pereonite 1 not broader than head. Pereonites 1 4 with mediodorsal spine on anterior margin each, pereonite 4 anterolateral projections small, acute. Frontal margin of pereonites 5 and 6 rounded, pleonite fused with pereonite 7 and separated from pleotelson by suture. Body without well protruding ventromedial spines. Pleotelson broadest anteriorly, almost as long as broad, anterolateral corners projecting frontally or laterally, posterolateral projections situated on posterior one-third of pleotelson, ventral preanal ridge well pronounced. Antenna 1 basal article subtriangular, article 2 less than one-third as long as article 1, article 3 in males much shorter and thicker than that in female. Dorsal suture between articles 1 and 2 of antenna 2 invisible, only lateral and ventral suture line present. Mandible incisor process broad in dorsal and in ventral views and narrow in lateral view, lacinia mobilis of left mandible relatively short, molar process narrowing distally. Pereopod 1 dactylar dorsal claw similar to that of following pereopods. Pereopods 3-4 only slightly longer than perepod 2. Pereopods 5-7 carpi about twice as long as wide, ventral margins straight; propodi oval, elongate, subequal in length to carpi, about third as long as wide. Male pleopod 1 bent ventrally, with serrated longitudinal keels. Pleopod 3 endopod and exopod with numerous distal plumose setae, exopod 2- segmanted, both articles subequal in width. Pleopod 4 exopod with one or a few plumose setae. Etymology. From Latin rectus, meaning straight, referring to the truncated tail. 14

15 Species included. See the following key. Except for the new ones all species are transferred from Storthyngura. Type species. Rectisura herculea (Birstein, 1957), by present designation. Distribution. Pacific ocean: northeastern Trenches, depth m; Kermadek Trench, depth m; Panama Basin, depth Atlantic ocean: South Antil Region, depth m. Key to species of Rectisura gen. n. 1 Pleotelson lateral margin rounded in front of posterolateral spines... 2 Pleotelson lateral margin angular in front of posterolateral spines Pleotelson dorsally only with a medial spine anteriorly and a pair of tubercles in the posterior half... 3 Pleotelson dorsally with long spines: one anteriorly and a pair of spines in the posterior half Pleotelson apex concave, its angles projecting laterally... 4 Pleotelson apex straight cut, its angles not projecting laterally Pleotelson posterolateral processes directed frontally, apical process rather short, lateral margins serrated R. serrata (Wolff, 1962) comb. n. Pleotelson posterolateral processes directed laterally, apex prominent, furcate R. furcata (Wolff, 1956) comb. n. 5 Natasoma spines long. Pleotelson posterolateral processes directed frontally R. distincta (Birstein, 1970) comb. n. Natasoma spines rather short Distance between pair of dorsal spines on pereonite 5 equal to that on following pereonites. Pleotelson posterolateral processes narrow, with angles about R. tenuispinis (Birstein, 1957) comb. n. Distance between pair of dorsal spines on pereonite 5 longer than on following pereonites. Pleotelson posterolateral processes with angles about R. richardsonae sp. n. 7 Body spines long, setulated. Pleotelson dorsally covered with long setae R. brachycephala (Birstein, 1957) comb. n. Body spines rather short, without setae. Pleotelson with 2 additional dorsomedial spines except anterior one and pair on posterior half; apex not protruding R. sepigia (George & Menzies, 1968) comb. n. 8 Pleotelson relatively short, broader than long, lateral spines long, truncated apex broad R. kurilica (Birstein, 1957) comb. n. Pleotelson relatively long, about as long as broad, lateral spines short, apical process relatively narrow Size large. Apex angles directed backwards R. herculea (Birstein, 1957) comb. n. Size small. Head with more convex lobes. Body spines long and thin. Pleotelson margins deeply emarginate... R. vitjazi (Birstein, 1957) comb. n. Rectisura richardsonae sp. n. (Figs 71-82) Material examined. Holotype male 19.5 mm (ZMMU Mc 1386): RV Akademik Kurchatov, cruise 11, St. 908, S, W, depth m. Paratypes (ZMMU Mc 1387): 1 damaged female about 17 mm; 1 female about 20 mm, with oostegites, without pleotelson; fragments of 3 additional specimens; all from the type locality. Description of holotype. Body (Figs 71, 72) with fragile integument, 2.7 times as long as pereonite 5 wide, measured without lateral spines, dorsal surface finely granulate, without setae. Head medially from point between antennae to posterior margin 0.4 times as long as wide, distance between bases of antennae 0.1 of basal antenna 1 width. Frons depressed, sloping, 0.3 as long as head totally, lateral bulges diverging under angle of about 40º, frontal arch short, perpendicular to clypeus, clypeus 1.6 times as wide as labrum, medially 0.6 times in dorsal view and 0.3 times in frontal view as long as labrum. Pereonite 1 as wide as head; posterolateral angles of pereonite 1 acute, those of following three pereonites rounded, anterolateral projections of pereonite 4 acute, minute, much shorter than coxal spines; pereonites 1 4 dorsomedial spine on frontal margin subequal to pereonite in length. Coxae of pereopods 1 4 with thin spine-like anterior projection subequal to pereonite's lateral length. Natasoma 1.5 times as long as anterior body part. Pereonite 5 with pair of thin dorsal spines on frontal margin placed relatively far from each other, following pereonites with pair smaller spines, situated nearer to each other than those on pereonite 5; anterolateral spine-like projections of pereonite 5 twice as long as those of pereonites 6 and 7. Pleonite half as long as following convex anterior part of 15

16 pleotelson. Pleotelson about as long as wide. Anterolateral acute processes directed outwards and slightly forwards, posterolateral processes subequal to anterolateral ones in size and shape, directed outwards, terminal projection between uropods short, straight truncate, with minute dorsal pore, distance from the dorsomedial pore to posterior margin 0.1 times as long as pleotelson, posterior margin of terminal projection 0.2 as wide as pleotelson; dorsum with medial anterior spine, rounded bulge behind it and a pair of acute tubercles in midlength; preanal ventral process rather long, rounded. Lateral margins of pereonites and pleotelson smooth, without setae. Antenna 1 (Fig. 73) about 0.3 times as long as body, article times as long as wide basally, central part 0.8 times as thick as wide, distolateral lobe not distinctly separated. Article 2 inserted after 0.7 of article 1 length from basal margin, almost as long as distolateral lobe of article 1, distal width with conspicuous distomedial process 0.45 of article 1 central width, articles , 0.2, and 0.7 times as long as article 2 respectively, flagellum of numerous, very short articles, with aesthetascs. Antenna 2 (Fig. 73) broken, only 4 basal articles present. Article 3 dorsally twice as long as article 2, distal spines rather narrow, distolateral spine slightly longer than distomedial one. Mandibles (Figs 74-76) incisor process broad in dorsal and ventral views, and narrow in frontal and inside views, with only 1 distinct tooth; lacinia mobilis of left mandible shorter than incisor process, with 5 teeth, spine row with 15 and 16 members in left and right mandibles respectively; molar process stout, narrowing in dorsal view, obliquely truncate; proximal ventral part of mandibular body surround with acute keel, proximal narrow acute projection well separated from body. Palp slightly shorter (0.9) than mandibular body, article 2 somewhat curved, 8 times as long as wide, 3 times as long as article 1, with thin setae on surface and row of distal stout setae rounded distally, similar to marginal setae of article 3. Maxilla 1 (Fig. 82) outer endite twice as wide as inner one, inner endite not angular distally. Maxilla 2 (Fig. 77) inner endite shortest, with numerous simple and 9-10 doubly serrated stout setae distally, outer and central endites with 4 spinelike distal setae, central endite with additional short finger-like setae. Maxilliped (Fig. 78) basis with proximomedial process, endite with 17 coupling hooks, distal margin inconspicuosly concave, with 9-10 fan-setae and numerous strong and thin simple setae, endite 0.7 times as wide as basis; palp as wide as basis, article times as wide as article 2, article times as long as article 2 laterally and 0.9 times medially, medial margin almost straight; articles 4 and 5 narrow and elongate, article 4 longer than terminal one. Epipod rounded distally, 2.6 times as long as wide, distal half of lateral margin concave, with tiny hook-like projection at central point. Bases of pereopods gradually decreasing and broadening from 1 to 5 and then increasing and narrowing to longest basis of pereopod 7 (length/width ratios are 5.7, 3.7, 3.0, 2.7, 2.6, 3.3, 3.9 respectively). Pereopod 1 (Fig. 79) 0.4 times as long as body, ischium 0.6 times as long as basis, both articles with sparse small setae, merus 0.2 times as long basis, carpus longest, 1.1 times as long as basis, conspicuously curved; propodus 0.6 times as long as carpus, about half as wide as carpus, both articles slender (about 13 times as long as wide), with small setae on surface; dactylus almost half as long as merus, dorsal claw stout, ventral claw forming transparent scabbard for two setae inbetween. Pereopod 2 (Fig. 79) ischium only slightly shorter than basis, carpus broken, with stout unequal bifid setae ventrally. Pereopods 3-4 missing, only bases present (Fig. 79) Pereopods 5-7 (Fig. 80) slightly longer than pereopod 1, pereopod 5 having shortest and broadest basis and largest carpus and propodus, pereopod 7 having opposite proportions; carpi 5-7 length/ width ratios are 1.9, 1.9, 1.8 respectively, ventral margin straight, dorsal margin convex, rounded; propodi length/ width ratios are 2.7, 2.6, 2.5; propodus slightly longer than carpus in all three legs (propodi length/ carpi length ratios are 1.17, 1.2, 1.18 ). Dactyli 5 7 only slightly longer than meri, with numerous thin, simple dorsal setae, dorsal claw of pereopod 5 triangular, without inner projection. Pleopod 1 (Fig. 81) 3.5 times al long as proximal wide, bent ventrally, with longitudinal serrated keels; narrowing part (waist) elongate, 0.4 times as wide as proximal part, distal one-fourth expanded, 1.5 times as wide as waist, looks like bulbous in ventral view. Distal tip with dense row of small setae ventrally, distal margin of inner lobes rounded, outer lobes small, narrow, protruded backwards; dorsal keels unvisible ventrally. Pleopod 2 (Fig. 81) 1.4 times as long as wide, pointed distomedially, lateral margin strongly convex, distolateral margin with row of short plumose setae, endopod inserted after 0.85 of protopod length from basal margin, stylet 0.3 times 16

17 as long as protopod, with short tapering tip; exopod short, thick, with tuft of fine simple setae on outer margin of hook, extrinsic musculature occupying small central part of protopod. Pleopod 3 (Fig. 82) endopod 0.7 times as long as pleopod 2, rounded, 1.5 times as long as wide, with 17 distolateral plumose setae; exopod 1.3 times as long as endopod, narrow, 0.2 as wide as endopod, distal article 0.3 times as long as proximal article, acute distally, with 18 distal plumose setae and row of thin simple lateral setae. Pleopod 4 (Fig. 82) endopod as long as wide, exopod half as wide and 0.85 as long as endopod, with 1 distal plumose seta. Pleopod 5 (Fig. 82) one lobe slightly longer than wide, banded laterally and covered lateral parts of pleopods 4 and 3. Uropod (Fig. 79) 0.6 times as long as pleotelson. Protopod slightly broadening distally, with a few distal setae, 3.3 times as long as wide distally and 6.6 times proximally. Endopod about half as wide and 1.2 times as long as protopod, with 4 strong unequal bifid and a few simple distal setae; exopod slightly narrower and 0.6 times as long as endopod, with 5 bifid distal setae. Female paratype similar to the male except sexual dimorphism. There are the following differences: antenna 1 (Fig. 73) article 1 larger and following article more slender, than in male, article times as long as basal wide, and 1.7 times as long as central part wide, central part 0.7 as thick as wide. Article times as long as article 1, distally 0.3 times as wide as article 1 central part; article 3 almost twice as long as that in male, articles , 0.3, and 0.3 times as long as article 2 respectively, flagellar articles numerous and short. Mandibles (Fig. 75): central tooth of lacinia mobilis longer than that in male, spine row with 17 and 18 members in left and right mandibles respectively. Palp article 1 (Fig. 74) visibly longer than that in male, article 2 twice as long as article 1, both articles with numerous fine setae, article 2 with distal row of 21 stout setulated setae. Propodi of pereopods 5-7 more slender than those in male, for example, length/width ratio of pereopod 5 propodus is 3.8 (2.7 in male) Operculum missing in the available specimen. Etymology. The species is named after the famous American isopodologist, Dr. Harriet Richardson. Remarks. The new species is most similar to R. tenuispinis (Birstein, 1957) and R. furcata (Wolff, 1956). These share the same arrangement of dorsal spines on pereonites and the general shape of the pleotelson. From R. tenuispinis, R. richardsonae sp. n. is distinguished by the slightly different shape of the pleotelson, with broader posterolateral acute processes and a wider distance between the pair of dorsal spines on pereonite 5. From R. furcata, R. richardsonae sp. n. is distinguished by the short, straight-cut pleotelson tip, which is more prominent and furcate in R. furcata. A similar row of fingerlike distal setae on article 2 of the mandibular palp is also exhibited by R. serrata (Wolff, 1962), R. sepigia (George & Menzies, 1968), and R. furcata. Distribution. Southern Atlantic ocean: Scotia Sea, at depths of m. Storthyngura Vanhöffen, 1914 Storthyngura Vanhöffen, 1914: 583. Hansen (1916: 132), Birstein (1957: 962), Menzies (1962: 145), Wolff (1962: 118), George & Menzies (1968b: ). Diagnosis. Body relatively flattened, of small size (2-6 mm). Head without dorsal spines (pair of tubercles in S. vemae Menzies, 1962 and S. magnispinis (Richardson, 1908)). Antenna 1 article 1 with almost parallel lateral contours, distolateral lobe rounded, weakly pronounced, medial spine usually small; article 2 longer than the lobe, narrow, without distomedial process. Antenna 2 article 1 well separated from article 2, with small, spine-like lateral projection. Pleotelson not pointed. Description. Head with small lateral projections near the insertion points of antennae 2 and mandibles; interantennular distance about half of antenna 1 basal width. Frons sloping, slightly concave medially, frontal arch broad, smooth, almost without lateral ridges. Pereonite 1 subequal in width to cephalon. Pereonites 2 4 with frontally directed dorsomedial spine each, broad at base. Anterolateral corners of pereonites 2 and 3 without projections in some species, or in other species with small anterolateral spines. Pereonites 5-7 fused, without dorsal sutures, with 1 or 2 medial projections anteriorly on each pereonite; sternum without spines. Pleotelson about as long as wide, without dorsal spines, anterolateral processes directed slightly frontally. Lateral margins between antero- and posterolateral corners either only slightly concave, or deeply cut frontally of the posterolateral projections. Preanal ventral ridge very short, rounded. All body margins with narrow transparent border, containing sparse minute setae. 17

18 Antenna 1 strongly sexually dimorphic, flagellum in females with a few long articles only, in males with numerous short articles. Maxilla 2 outer and central endites with additional small medial seta. Maxilliped endite elongate, with few slender coupling hooks. Medial margin of palp article 2 somewhat concave, distinctly longer than that of article 3. Epipod lateral margin without acute projection on midlength. Pereopods 2-4 insignificantly increasing in length from 2 to 4; carpi 3 and 4 with several unequally bifid spinelike setae on ventral distal third (it was studied only in S. elegans Vanhöffen, 1914, S. parka Malyutina & Wägele, 2001). Pereopods 5-7 carpi in S. elegans, S. parka and S. octospinosalis Menzies & George, 1972 crescent-shaped, propodi narrow, shorter than carpi. S. kussakini Brandt & Malyutina, 2002 is the only species having narrow carpi and propodi of last pereopods, like species of Storthyngurella. Pleopod 3 endopod with 3-4 plumose setae distally, distal article of exopod broad distally; pleopod 4 exopod narrow, not reaching apical margin of endopod, with 1 distal plumose seta. Remarks. Except for three species the published descriptions are very brief, with incomplete illustrations. Some species (for example, S. snanoi Menzies, 1962 and S. octospinosalis) seem to have been described from juvenile specimens. The real relationships in this group could not be clarified during the present work. This would be possible when additional material becomes available for a comparative study. A future analysis will perhaps lead to further division of Storthyngura into at least two more genera. Species included. See following key. Type species. S. elegans Vanhöffen, Distribution. Northern hemisphere: one species from the North Pacific, depth 5011 m, and four species from the West Atlantic, depth m; all remaining species occur in the southern hemisphere: in the East Pacific off Peru, depth m. and in the Antarctic, depth m. Key to species of Storthyngura 1 Posterior margin of pleotelson with notches for uropod insertions, terminal process and posterolateral projections separated... 2 Posterior margin of pleotelson rounded... S. intermedia (Beddard, 1885) (tentative placement) 2 Anterolateral corners of pereonites 2 and 3 rounded... 3 Anterolateral corners of pereonites 2 and 3 pointed, slightly projecting Pereonite 1 without dorsomedial spine... 4 Pereonite 1 with dorsomedial spine Lateral spines of pleotelson pointed, terminal projection with medial notch, Coxal spines long..... S. elegans Vanhöffen, 1914 Lateral spines of pleotelson rounded, terminal projection somewhat convex. Coxal spines short.... S. parka Malyutina & Wägele, Natasoma broad. Pleotelson broader than long, without dorsal spines S. kussakini Brandt & Malyutina, 2002 Natasoma narrow. Pleotelson longer than broad, with pair of dorsal spines S. octospinosalis Menzies & George, Body without dorsal spines, except for paired minute tubercles on posterior part of pleotelson S. truncata (Richardson, 1908) Body with dorsal spines Pereonites 6 and 7 without dorsal pair of spines S. snanoi Menzies, 1962 Pereonites 6 and 7 with dorsal pair of spines Lateral projections of natasoma rounded apically.... S. vemae Menzies, 1962 Lateral projections of natasoma acute S. magnispinis (Richardson, 1908) Acknowledgements The project was performed with partial financial support of the Deutsche Forschungsgemeinschaft (DFG), grant 436 RUS 17/20/02. It is also a contribution of the DIVA 1 project, supported by DFG grant Wa 530/27-1. I am deeply indebted to colleagues from the Laboratory of Benthos in the Shirshov Institute of Oceanology, Moscow, for the privilege of being able to examine the Storthyngura collections. I am grateful to B. Mezhov (Zoological Museum of Moscow University), Dr. B. Kensley (U.S. National Museum of Natural History, Washington), Mrs. E. Borda (American Museum of Natural History, New York), and Dr. N. Bruce, former curator of Crustacea (Zoological Museum of Copenhagen University), for the kind loan of the type material of some Storthyngura species. I thank Prof. Dr. W. Wägele and Prof. Dr. A. Brandt, and 18

19 also anonymous reviewers, whose remarks helped improve the manuscript. References Birstein, Y. A. (1957): Certain peculiarities of the ultra-abyssal fauna at the example of the genus Storthyngura (Crustacea Isopoda Asellota). Zool. Zh. 36: [in Russian] Birstein, Y. A. (1969): Crustacea Isopoda from the Romanche Trench. Byull. Mosk. Obshch. Ispytatelei Prir. Otdel Biol. 3: [in Russian] Birstein, Y. A. (1970): Additions to the fauna of Crustacea Isopoda of the Kurilo-Kamchatka Trench. Trudi Inst. Oceanol. im. P. P. Shirshova 86: [in Russian] Brandt, A. & Malyutina, M. V. (2002): Storthyngura kussakini sp. n. from the Southern Ocean. Mitt. Mus. Naturk., Berlin, Zool. Reihe 78: George, R.Y. & Menzies, R. J. (1968a): Species of Storthyngura (Isopoda) from the Antarctic with descriptions of six new species. Crustaceana 14: George, R.Y. & Menzies, R. J. (1968b): Distribution and probable origin of the species in the deep-sea isopod genus Storthyngura. Crustaceana 15: Hansen, H. J. (1916): Crustacea Malacostraca III. V. The order Isopoda. Danish Ingolf Exped. 3: Kussakin, O. G. (2003): Morskye I solonovatovodnye ravnonogie rakoobrasnye (Isopoda) cholodnix I umerennix vod severnogo polushariya. T. III. Suborder Asellota. Part 3. Family Munnopsidae. 381 pp., Nauka, St. Petersburg. [in Russian] Malyutina, M. V. (1999a): Storthyngurella, new genus of Munnopsidae (Crustacea: Isopoda), with descriptions of three new species from deep-sea basins of the southern hemisphere. Mem. Mus. Victoria 57: Malyutina, M. V. (1999b): New species of Acanthocope (Crustacea, Isopoda, Munnopsidae). Russ. J. Mar. Biol. 25: Malyutina, M. V. & Wägele, J. W. (2001): Redescription of Storthyngura elegans Vanhöffen, 1914 and description of a new deep-sea species of Storthyngura from the Peru Basin. Mitt. Mus. Naturk., Berlin, Zool. Reihe 77: Menzies, R. J. (1962): The isopods of abyssal depths in the Atlantic Ocean. Vema Res. Ser. 1: Vanhöffen, E. (1914): Die Isopoden der Deutschen Südpolar Expedition 20, Zool. 7: Wilson, G. D. & Hessler, R. R. (1980): Taxonomic characters in the morphology of the genus Eurycope (Isopoda, Asellota) with a redescription of Eurycope cornuta G. O. Sars, Cah. Biol. Mar. 21: Wilson, G. D. (1989): A systematic revision of the deep-sea subfamily Lipomerinae of the isopod crustacean family Munnopsidae. Bull. Scripps Inst. Oceanogr. Univ. California, San Diego 27: Wilson, G. D., Kussakin, O. G. & Vasina, G. S. (1989): A revision of the genus Microprotus Richardson with descriptions of two new species, M. acutispinatus and M. lobispinatus (Asellota, Isopoda, Crustacea). Proc. Biol. Soc. Wash. 102: Wolff, T. (1962): The systematics and biology of bathyal and abyssal Isopoda Asellota. Galathea Rep. 6:

20 20 Fig. 1. Representatives of six genera of subfamily Storthyngurinae: a, Storthyngura elegans Vanhöffen, 1914 (from Malyutina & Wägele 2001); b, Microprotus caecus Richardson, 1910 (from Wilson et al. 1989); c, Storthyngurella hirsuta Malyutina, 1999 (from Malyutina 1999a); d, Vanhoeffenella pulchra (Hansen, 1897) gen. n. (after photographs in Wolff 1962); e, Rectisura richardsonae gen. n., sp. n.; f, Sursumura praegrandis (George & Menzies, 1968) gen. n. (specimen from St. 927 (Kurchatov-11)).