A preliminary report on dinosaur track assemblages from the Mid dle Ju ras sic of the Imilchil area, Mo rocco

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1 Geo log i cal Quar terly, 2009, 53 (4): SHORT COMMUNICATION A preliminary report on dinosaur track assemblages from the Mid dle Ju ras sic of the Imilchil area, Mo rocco Gerard D. GIERLIŃSKI, Piotr MENDUCKI, Katarzyna JANISZEWSKA, Ireneusz WICIK and Andrzej BOCZAROWSKI Gierliński G. D., Menducki P., Janiszewska K., Wicik I. and Boczarowski A. (2009) A pre lim i nary re port on di no saur track as sem - blages from the Mid dle Ju ras sic of the Imilchil area, Mo rocco. Geol. Quart., 53 (4): Warszawa. Di no saur tracks are re ported from three new lo cal i ties near Imilchil, in the Cen tral High At las of Mo rocco. New di no saur track as sem - blages are rec og nized in Bathonian and Bajocian beds. The Bathonian track as sem blage com prises theropod, sauropod and ornithopod foot prints. The Bajocian de pos its con tain a sauropod-thyreophoran track as sem blage. Gerard D. Gierliński, Pol ish Geo log i cal In sti tute Na tional Re search In sti tute, Rakowiecka 4, Warszawa, Po land; gierlinski@ya hoo.com; Gerard D. Gierliński, Piotr Menducki, Katarzyna Janiszewska and Ireneusz Wicik, JuraPark, Sandomierska 4, Ostrowiec Świętokrzyski, Po land; Andrzej Boczarowski, Fac ulty of Earth Sci ences, Uni ver sity of Silesia, Będzińska 60, PL Sosnowiec, Po land; a.boczarowski@chello.pl (re ceived: July 24, 2009; ac cepted: De cem ber 14, 2009). Key words: Di no saur tracks, Bathonian, Bajocian, Cen tral High At las, Mo rocco. INTRODUCTION The sites re ported are lo cated to the west of Imilchil, in the Cen tral High At las of Mo rocco (Fig. 1). The first di no saur tracksite (site A) near Imilchil was dis cov ered by one of us (PM), in Oc to ber In April 2009, a join ex pe di tion of the JuraPark Ex plorer Team and the Pol ish Geo log i cal In sti - tute-na tional Re search In sti tute found two more sites in that area. The sites are lo cated along the road from Imilchil to Tabanast. Over a few days, we col lected as much data as was pos si ble, in clud ing casts of the ichnites dis cov ered. Resin rep li - cas of those spec i mens have been stored in the JuraPark col lec - tion in Bałtów, Po land, where they are avail able for the fu ture study. The Tethyan At las sys tem com prises two dis tinct branches the High and Mid dle At las which were tec - toni cally ac tive ar eas dur ing Early Ju ras sic times. The High At las in cen tral Mo rocco rises in the west at the At lan tic coast and stretches eastwards to the Mo roc can-al ge rian bor der (Michard et al., 2008). The High At las Trough was formed dur ing the early rift ing of Af rica and North Amer ica (Ev ans et al., 1974). Sedimentological ev i dence in di cates that sub si - dence of the trough was not ac com pa nied by in tense crustal de for ma tion. A con ti nen tal rift opened in the Late Tri as sic, accumulating redbeds, evaporites and basalts. Marine carbonate sedimentation commenced in Hettangian Sinemurian (earliest Jurassic) and continued until the Middle Jurassic, when the ba sin ceased to sub side and be came once more con - tinental (Evans et al., 1974). The stra tig ra phy of the At las redbeds is based on ver te brate, ostracod and charophyte fos - sils. The nu mer ous tec tonic fea tures as so ci ated with the Ju ras - sic sed i men tary rocks of this area prob a bly de vel oped at a later, post-ju ras sic stage. Post-Ju ras sic up lift and tec tonic in - ver sion cre ated the su perb ex po sures of the mod ern Cen tral and East ern High At las (Warme, 1988). DESCRIPTIONS OF TRACKSITES SITE A The site is lo cated at the north ern side of road 1903, near the vil lage of Ait Ali Ou Ikkou. Ac cord ing to Fadile (2003), the ex - posed dolomites are Bajocian in age. The main track-bear ing sur face, lo cated at the GPS co or di nates N and W ,742, com prises me dium-sized theropod foot prints and a two-step sauropod trackway (Fig. 2). The tracks are pre served

2 478 Gerard D. Gierliński, Piotr Menducki, Katarzyna Janiszewska, Ireneusz Wicik and Andrzej Boczarowski Fig. 1. Lo ca tion of the new di no saur tracksites in the Cen tral High At las of Mo rocco A map of Mo rocco; B geo log i cal map of the Imilchil area, af ter Fadile (2003) as nat u ral moulds on the layer, which dips to the south-east at an av er age of 60. The theropod foot prints (Fig. 2B) are ran domly ori ented and look like di min u tive ver sions of Megalosauripus sensu Lockley et al. (1996, 1998b). Their size (pes length 36 cm) fits the size range of Therangospodus Lockley et al., 1998a. How - ever, they dif fer from Therangospodus by a more pro jected third toe and de fined phalangeal pads. Changpeipus Young, 1960, seems to be the best match for those foot prints. Changpeipus was orig i nally de scribed by Young (1960) from the Mid dle Ju ras sic of China, but re cently was also re ported from the Lower Ju ras sic of China (Xing et al., 2009). There is also a nar row-gauge sauropod trackway di rected eastwards (Fig. 2A). The pedal print length is 40 cm and its width is 29 cm, while the man ual print is 11 cm long and 24 cm wide. Fol low ing the sauropod track des ig na tion con cept of Lockley, Farlow et Meyer (1994), our spec i men cor re sponds with the nar row-gauge trackway morphotype named Parabrontopodus Lockley, Farlow et Meyer, Above the main sur face, there are an other track-bear ing ho ri - zons. The up per part of the site re vealed a few theropod foot - prints and one ornithopod ichnite (Fig. 3). The small est theropod foot print (cast JuraPark J386) is only 2 cm long (Fig. 3A) and was found at GPS co or di nates N , W 005 o This footprint resembles the diminutive ichnites Wildeichnus

3 A preliminary report on dinosaur track assemblages from the Middle Jurassic of the Imilchil area, Morocco 479 Fig. 2. The main track-bear ing sur face at site A, Bajocian of the Imilchil area, Mo rocco A Parabrontopodus sp. (spec i men cast: JuraPark J523); B Changpeipus sp. (spec i men cast: JuraPark J383) Fig. 3. Iso lated foot prints found above the main sur face at site A, Bajocian of the Imilchil area, Mo rocco A Wildeichnus sp. (spec i men cast: JuraPark J386); B Jialingpus sp. (spec i men cast: JuraPark J387); C Carmelopodus (spec i men cast: JuraPark J385); D Therangospodus sp.; E cf. Dinehichnus sp. (spec i men cast: JuraPark J384)

4 480 Gerard D. Gierliński, Piotr Menducki, Katarzyna Janiszewska, Ireneusz Wicik and Andrzej Boczarowski Casamiquela, 1964, known from the Mid dle Ju ras sic of Ar gen - tina and Utah, USA (Leonardi, 1994; Lockley et al., 2007), and the Up per Ju ras sic of Po land (Gierliński et al., 2009). The other small theropod track (cast JuraPark J387) was found at GPS co or di nates: N , W The foot print is 12 cm long and char ac ter ized by the large elon gate metatarsophalangeal pad of digit IV which mark edly ex tends pos te ri orly from the prox i mal (metatarsophalangeal) area of the foot print (see, Fig. 3B). It cor re sponds with the ichnogenus Jialingpus Zhen, Li et Zhen, 1983, de scribed from the Up per Ju ras sic of China and Po land (e.g., Zhen et al., 1989; Gierliński et al., 2009). A nat u ral cast of a small theropod foot print (12 cm long), was found on an iso lated slab, at GPS co or di nates N and W This is the only spec i men (cast JuraPark J385) de scribed in this pa per that is pre served as con vex hyporelief. The pedal dig its clearly lack their prox i mal pads (Fig. 3C). Sim i lar foot prints from the Mid dle Ju ras sic of North Amer ica were la beled as Carmelopodus Lockley et al., The pos si ble pres ence of Carmelopodus in the Mid dle Ju ras sic of Mo rocco has been pre vi ously sug gested by Meyer and Monbaron (2002). Sev eral Carmelopodus tracks were also found more re cently, in the Bathonian beds close to Imilchil. A me dium-sized (29 cm long) theropod track (Fig. 3D) with co alesced phalangeal pads was found at GPS co or di nates N and W Its mor phol ogy strongly re - sem bles that of Therangospodus, an ichnogenus known from the Mid dle Ju ras sic of North Amer ica, the Up per Ju ras sic and Lower Cre ta ceous of Eu rope, and the Up per Ju ras sic of Cen tral Asia (Lockley et al., 1998a; Gierliński, 2009). The most in trigu ing spec i men in the re ported as sem blage is a well-pre served foot print (cast JuraPark J384; Fig. 3E) dis cov - ered at co or di nates N and W In con - trast to above-men tioned theropod ichnites, this is a tridactyl track with the mid dle toe highly pro jected and be ing the lon gest digit, the dig its other be ing rel a tively shorter and subequal in length and ar ranged in the ornithischian track fash ion. The sim - i lar foot print (ex cept for the hallux pres ence) has been de - scribed from the Up per Ju ras sic of Po land as a sup posed camptosaurid track (Gierliński et al., 2001, 2009). The foot - print is nearly as long as wide (22 cm long and 23 cm width), with ci gar-shaped, highly and equally divericated dig its, and the dis crete, oval prox i mal pad lo cated al most cen trally be low the mid dle toe. Its mor phol ogy re sem bles the ichnogenus Dinehichnus Lockley, Santos, Meyer and Hunt, 1998, orig i - nally de scribed from the Up per Ju ras sic of North Amer ica and later re ported also from the Up per Ju ras sic of Eu rope (Gierliński, 2009; Gierliński et al., 2009). SITE B Site B is the top of a layer, dip ping some 30 to the south, tram pled by sauro pods. Sev eral sauropod trackways di rected to the east have been dis tin guished. The site is lo cated at the north - ern side of road 3425, at GPS co or di nates: N and W Many trackways are shal lowly im pressed, but some are deep and well pre served, such as the one il lus trated on Figure 4. The trackways clearly show a nar row-gauge Parabrontopodus pat tern. The tracks are much larger than the Fig. 4. Parabrontopodus sp. (no casts made) from site B Bathonian of the Imilchil area, Mo rocco

5 A preliminary report on dinosaur track assemblages from the Middle Jurassic of the Imilchil area, Morocco 481 Fig. 5. cf. Stegopodus sp. (spec i men cast: JuraPark J388) from site C, Bathonian of the Imilchil area, Mo rocco Bajocian sauropod tracks de scribed at site A. The pedal prints are ap prox i mately 80 cm long and 60 cm wide, while the man ual prints are 20 cm long and 40 cm wide. Ac cord ing to Fadile (2003), the ex posed strata are Bathonian in age. SITE C This is an other Bathonian out crop (GPS co or di nates: N , W ) lo cated at the north ern side of road 3425, close to the vil lage of Tabanast. The site com prises an ornithischian bipedal trackway di rected north wards (Fig. 5) pre served on a sur face dip ping at ca.10 to the south. The foot print (cast JuraPark J388) is rel a tively large, slightly wider than long (27 cm long and 29 cm wide), tridactyl and blunt-toed. Dig its are very short, broad, widely divaricated and barely pro ject be yond the hypex. Pes is asym met ri cal, with the prox i mal pad lo cated posterolaterally. All these dis - tinc tive fea tures fit the di ag nos tic traits of Stegopodus sensu Gierliński and Sabath (2008). CONCLUSIONS The ichnofauna briefly re ported herein, with Changpeipus sp., Wildeichnus sp., Carmelopodus and Therangospodus sp., sup ports the Mid dle Ju ras sic age of these di no saur track as sem - blages. More over, the range of dis tinc tive ichnites of Carmelopodus seems to be in dic a tive of a Bajocian Bathonian age world wide (Lockley et al., 1998; Lockley and Meyer, 2000; Ad ams and Breithaupt, 2003; Gierliński and Nowacki, 2008). This ichnogenus is known from the Car mel For ma tion (Bajocian Bathonian) of Utah, the Sundance For ma tion (Bathonian) of Wy o ming, the For est Mar ble (Bathonian) of Eng land and the Kościelisko Beds (Bajocian) of Po land (the Pol ish spec i men is stored in the JuraPark col lec tion as J483). In con trast to Changpeipus sp., Wildeichnus sp., Carmelopodus and Therangospodus sp., the me dium ornitho - pod ichnite cf. Dinehichnus sp., the small theropod foot print Jialingpus sp. and the stegosaurian track cf. Stegopodus sp. have hith erto been re corded in Late Ju ras sic de pos its only. It is also noteworthy that Wildeichnus sp., Jialingpus sp., Therangospodus sp., Changpeipus sp., cf. Dinehichnus sp. and cf. Stegopodus sp. are rec og nized for the first time in the Ju ras - sic strata of Af rica. Acknowledgments. We would like to thank L. Adach from the Polish Geological Institute-National Research Institute and Dr. S. Ishigaki from the Hayashibara Mu seum of Nat u ral Sci - ences for pro vid ing ref er ences on the ge ol ogy of the study area. We thank Dr hab. G. Pieńkowski of the Pol ish Geo log i cal In sti - tute-na tional Re search In sti tute for valu able re marks and for reviewing this paper.

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