Mid Dle De Vo Nian Brachio Pods from the South Ern Ma

Annales Societatis Geologorum Poloniae (2013), vol. 83: 243–307. MIDDLE DEVO NIAN BRACHIO PODS FROM THE SOUTH ERN MADER (EASTERN ANTI- ATLAS, MO ROCCO) Adam T. HALAM SKI & Andrzej BALIÑSKI In stitute of Paleo biology, Polish Academy of Sciences, Twarda 51/55, PL-00- 818 Warszawa, Poland; e-mails: [email protected], [email protected] Ha lam ski, A. T. & Bali ñski, A., 2013. Mid dle De vo nian brachio pods from the southern MaÎder (eastern Anti-Atlas, Mo rocco). An nales So cie ta tis Ge olo go rum Po lo niae, 83: 243–307. Ab stract: Sixty- two Middle De vo nian brachio pod spe cies are de scribed on the ba sis of >1300 speci mens from the Tabou ma khloõf Forma tion (and sub or di nately proba bly also from the top of the El Ot fal For mation) at Ma- dÀne el Mrakib (middle to late Eifelian or early Giv etian?), Afer dou el Mrakib (late Eifelian to mid dle Givetian), and Guelb el Ma harch (early Giv etian) on the south ern edge of the MaÎder Syn cline (eastern Anti-Atlas, Mo - rocco). Rep re sen ta tives of Cra niida (2 taxa), Stro phomen ida (5), Pro duc tida (2), Or tho tet ida (2), Or thida (5), Pen tame rida (5), Rhyn chonel lida (9), Atrypida (14), Athy ridida (7), Spirif erida (9), and Spirif er inida (2) are pres ent. The fauna is domi nated quan ti ta tively by the Atrypida (24% of taxa, about the half of speci mens, and the com mon est spe cies Atry paria dis persa making up about 13% of the mate rial); the Rhyn chonel lida (16% of taxa, about one- sixth of speci mens) are the sec ond larg est or der. A new ge nus of the fam ily Pugnaci dae (or der Rhyn - chonel lida), Pau linaer hynchia, is pro posed with the type spe cies P. pau li nae gen. et sp. nov. from Maharch; it is clos est to Pug nax, from which it dif fers in dis tinct costa tion, lack of a dor sal sep tum and sep talium, and ru di men- tary den tal plates. Desquama tia (D.) deserti sp. nov., a large and finely co state rep re sen ta tive of the ge nus, is described also from Ma harch. An tirhyn chonella and Glosshy po thy ri dina are re ported for the first time or con - firmed to be pres ent in the Giv etian. Forty (possi bly up to 46) spe cies (71 or pos si bly up to 82% of the taxa iden ti fied at the spe cies level) are pres ent also in ei ther Eifel (Ger many) or the Holy Cross Mountains (Po land). Such a high ra tio of spe cies in com mon at tests to un con strained fau nal ex changes among ben thic fau nas be tween the north ern and south ern shores of the Varis can Sea dur ing the Mid dle De vo nian. This fa vours the palaeo geo - graphic hy pothe sis of a nar row Varis can Sea. Key words: sys te mat ics, Brachio poda, Mo rocco, De vo nian, Eife lian, Giv etian, Varis can Sea, pa laeo bio ge o- g ra phy. Manu script re ceived 11 March 2013, ac cepted 27 December 2013 IN TRO DUC TION His tory of re search The rich ness of Palaeozoic fau nas in the Mo roc can Geological stud ies in the eastern Anti-At las began only Anti-Atlas is famed. Devo nian brachi o pods, the major fau- in the 1930s. As far as it was pos sible to estab lish, the first nal com po nent in sev eral geo log i cal units, are es pe cially nu - palaeontologist to de scribe De vo nian brachi o pods from mer ous and di ver si fied. How ever, de spite sev eral stud ies by MaÎder was Dorothée Le Maître. On the ba sis of Geor ges pre vi ous au thors, Mid dle De vo nian brachi o pods still are re- Choubert’s collec tions, she reported a small faunule from latively poorly known, owing to, among other factors, col- “Merakib” in the MaÎder Syncline (Le Maître, 1939). Al- lec tions having been assem bled in large part for purposes of though the bulk of the fauna is Early Devo nian in age, a part geolog i cal mapping. The aim of the present pa per is (i) to of it might belong to the Middle Devo nian. The de tailed pres ent a de tailed system atic account of a middle Eifelian to study of this fauna, announced in the above-mentioned pa- middle Givetian brachio pod fauna from three nearby lo cal i- per, has never ap peared. ties in the southern MaÎder; (ii) to de fine its palaeobiogeo- The sys tem atic study of De vo nian brachi o pods from graphic af fini ties, which lie, as will be shown, within the MaÎder is mainly the work of geol o gist Henri Hollard, who Rhenish subprovince; (iii) last, to discuss the im pact of the collected ex tensively in Morocco for over twenty years new data upon ques tions of the width of the Variscan Sea (Hollard, 1962, 1963, 1974, 1985) and of palaeontologist and of the sep ara tion between Rhenish- and Ameri can-type Jeannine Drot. In a series of papers dealing with Si lurian brachi o pod fau nas in the Mid dle De vo nian of north west ern and De vo nian brachi o pods of the pre-Sa ha ran Mo rocco Af rica. (Anti-Atlas and north ern flank of the Tindouf Syncline), 244 A. T. HALAMSKI & A. BALIÑSKI MID DLE DE VO NIAN BRACHI O PODS FROM THE SOUTH ERN MADER (MAROCCO) 245 Drot (1964, 1966, 1971) described several taxa of Mid dle scriptions: Jebel Issoumour, Jbel Issimour; includ ing the Devo nian rhynchonellides and spiriferides from the MaÎder solitary hill called Jebel Abiir), Jebel (el) Otfal, Jebel (includ ing Aferdou el Mrakib). Middle De vo nian stropho- Maharch, Jebel (el) Mrakib, and Jebel OufatÀne (Fig. 1C). menides, productides, orthotetides, orthides, pentamerides, The present paper is based on the mate rial from three out- athyridides, and atrypides have not been under detailed re- crops, sit u ated in the south ern part of these ranges (geo logic search. map sheet Todrha-Ma’der, du Dresnay et al., 1988), namely Struve (1995) il lustrated and briefly com mented upon MadÀne el Mrakib, Aferdou el Mrakib and Guelb (el) sev eral Mid dle De vo nian pentamerides, atrypides, and Maharch. spiriferides from the northern MaÎder (Jebel Issomour). He In the Mid dle Devo nian (Fig. 1A), the present Anti-At- also listed sev eral other taxa (identi fied at ge nus level) and las region formed a part of the pas sive north-western margin con cluded that the af fil ia tion of the fauna was re fer able to of Gondwana (Piqué et al., 1993) at a palaeolatitude of about the Rhenish subprovince. Sin gle Givetian brachio pod spe- 30–40° S (Scotese and McKerrow, 1990; Matte, 2001; Go- cies from MaÎder were described by Godefroid (2000), lonka et al., 2006; Torsvik and Cocks, 2011; Stampfli et al., Schemm-Gregory (2009), and Franchi et al. (2012). 2013). In general, the eastern part of the Anti-Atlas is charac - Last but not least, it is appro pri ate to note some major ter ised during the entire Devo nian by sedi ments with rel a- results regard ing the geol ogy of the study area. The age of tively low content of clastic and terrigenous com ponents (as the coral limestone (calcaire coralligÀne), now corre spond - compared to the west ern part; Piqué and Michard, 1989). ing to a part of the Taboumakhloõf For ma tion (Hollard, The sub divi sion of the eastern Anti-At las into four deposi- 1974), was estab lished as Givetian by Hollard (1962; con- tional realms (from west to east, the MaÎder Platform, the sidered as Eifelian by Delépine, 1951). The strati graphic de- MaÎder Ba sin, the Tafilalt Plat form, the Tafilalt Ba sin) re - scrip tion of the MaÎder was presented by Hollard, first in sulted from bathymetric differ en ti ation of the basin, due to brief (Hollard, 1963) and then in detail (Hollard, 1981). A early Variscan block faulting in the late Emsian (Wendt, sedimentological study of the three sites, from which the 1985, 1988; Belka et al., 1997). Aferdou el Mrakib and fauna de scribed in the pres ent pa per comes, was done by Guelb el Maharch are the two larg est bioconstructions, sev- Kaufmann (1998). Cono dont-based stratig raphy of the eral of which devel oped in a wide neritic facies belt, surrou- Eifelian of the eastern Anti-At las was pre sented by Belka et nding the cen tral basinal part of the MaÎder Basin (Wendt, al. (1997). The Devo nian palaeo geogra phy of the Anti-At- 1993; Kaufmann, 1995). It may be noted that sim ilar early las was dealt with by Wendt (1985, 1988, 1993), by Belka et Givetian reefs and mud mounds devel oped on both sides of al. (1997), and by Döring and Kazmierczak (2001). the Variscan Ocean: on the northern borders of Gondwana further west (pres ent-day West ern Sa hara: Dumestre and Illing, 1967; Wendt and Kaufmann, 2004) and east (Wendt GEO LOGIC SET TING et al., 1997), as well as on the south ern borders of Eurame- rica (present-day Sauerland: Krebs, 1967; May, 2003; pres- The MaÎder (spelt also Ma’der, Mader, Maader, and ent-day Eifel: Schmid et al., 2001; present-day New York: MaÎdÀre) is a Variscan syncline, sit u ated in the east ern part Heckel, 1972; see also Krause, 2004).

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