984 J. Paleont., 82(5), 2008, pp. 984–995 Copyright  2008, The Paleontological Society 0022-3360/08/0082-984$03.00 FAMENNIAN CHONDRICHTHYAN MICROREMAINS FROM MOROCCO AND SARDINIA CLAIRE DERYCKE, 1 CLAUDIA SPALLETTA, 2 MARIA CRISTINA PERRI, 2 AND CARLO CORRADINI 3 1 Universite ´ Lille 1, Laboratoire Ge ´osyste `mes (UMR 8157 CNRS) UFR des Sciences de la Terre - ba ˆtiment SN5 59655 Villeneuve D’ascq Cedex, France, claire.derycke@univ-lille1.fr; 2 Dipartimento Di Scienze Della Terra E Geologico-Ambientali, Universita’ Degli Studi Di Bologna, Via Zamboni 67, I-40126 Bologna, Italy, claudia.spalletta@ unibo.it, mariacristina.perri@ unibo.it; and 3 Dipartimento Di Scienze Della Terra, Universita’ Di Cagliari, Via Trentino 51, I-09127 Cagliari, Italy, corradin@unica.it ABSTRACT—New material from the Famennian of Morocco in the southern Maider comprises chondrichthyan teeth (Thrinacodus, Cobelodus, Denaea, Stethacanthus), actinopterygian remains (scales, teeth and hemilepidotrichium) and one acanthodian scale. The absence of crushing teeth suggests deeper water environments for the Maider Basin than the Tafilalt Basin. Vertebrate microremains from the Famennian of Sardinia, including Siamodus and Jalodus teeth, are illustrated and described. Ichthyofaunal relationships of the North Gondwanan platform during the Famennian are examined. INTRODUCTION Morocco.FAMENNIAN VERTEBRATE microremains previously reported essentially from the Tafilalt and Maider, Morocco, were primarily placoderms, sarcopterygians (Lehman, 1975, 1976a, 1976b; Lelie `vre, 1984; Lelie `vre and Janvier, 1986) and chondri- chthyans (Lelie `vre et al., 1993, p. 148–150). With regard to the last group, the first remains of selachians described from Morocco were a spine and dental plates from the late Eifelian of the Dra Plain of the south-western Anti-Atlas by Lehman (1976a). He obtained Ctenacanthus spines in younger horizons (Frasnian) be- tween Jebel Amessaoui and Jebel Titert of the Tafilalt in the north- eastern Anti-Atlas (Lehman, 1976b). From the late Famennian of Tafilalt, Lehman (1977) reported a Ctenacanthus spine, later iden- tified as C. venustus (Derycke, 1992, dated by conodonts middle Famennian by Bultynck) and a selachian tooth resembling those of Orodus. Other chondrichthyan remains (teeth and scales) were reported by Lelie `vre (1984) in the Emsian of the Dra plain. Teeth and spines from the Famennian of Hamar Lagdad and Oued Chebbi (Tafilalt) were mentioned by Lelie `vre and Janvier (1988). Subsequent publications concern late Famennian chondrichthyan remains from the Tafilalt (Derycke, 1992) and from two localities near Taouz (southern part of the Tafilalt Platform) (Ginter et al., 2002). This is the first record of vertebrate microremains from the Maider Basin. Mrakib Section.Samples for conodonts and microremains of fishes from the late Famennian in the Mrakib section in the Maid- er basin of the Anti-Atlas of southern Morocco were collected and acid-leached by CS, MCP and CC (Figs. 1, 2). The paleo- geography of the eastern Anti-Atlas is constrained by Variscan tectonics. Geological studies show evidence of a general deep- ening; the Maider basin has been considered deeper environmen- tally than the Tafilalt basin (Wendt et al., 1984; Wendt and Aigner, 1985). Being one of the most nearly complete middle and late Fa- mennian sequences, the Mrakib section has been suggested as a candidate for the stratotype for the base of the late Famennian substage. It consists of more than 100 m of predominantly fine siliciclastics interbedded with calcareous layers deposited under mostly poorly-oxygenated conditions (Becker et al., 1999). Its abundant, highly diverse ammonoid faunas have been document- ed (Becker et al., 1999), as have its crinoids (Webster et al., 2005). The faunas are reported to include bivalves, gastropods, brachio- pods, ostracods, trilobites, corals, nautiloids, placoderm plates, and foraminifers (Becker et al., 1999), but these have yet to be documented. Seven samples of the marly calcareous horizons rich in am- monoids were sampled for conodonts and microremains of fishes. Of these samples, N2, R1, and T were productive; T produced only fish teeth. The conodonts indicate broad ages: N2 is Upper crepida–Upper expansa Zones, and R1, Lower–Upper expansa Zones (Fig. 2, Table 1). According to Webster et al. (2005), a more precise time attribution for level N2 is suggested by the ammonoid content of the Annulata Limestone lying, in terms of conodont biostratigraphy, near the boundary between the Upper trachytera and the Lower postera Zones (Ziegler, 1962). Because of imprecision of the conodont data for indicating ages, it has been suggested that the Mrakib section be discarded as a potential stratotype for the base of the late Famennian (Corradini et al., 2001). Ichthyofauna from sample N2, presenting a new and interesting association, includes 10 chondrichthyan teeth, scale fragments, actinopterygian teeth, and an acanthodian scale. Sample R1 pro- duced Symmoridae remains, one tooth and one scale. Sardinia.The occurrence of fish remains in the Palaeozoic of Sardinia has been reported by Corradini (1998, 2003) and Cor- radini et al. (2003). As the authors did not illustrate and discuss the fauna, the material here presented constitutes the first docu- mented Palaeozoic ichthyofauna from this region. No macroscop- ic remains have ever been found on the island (Randon, 2002; Randon et al., in press). Vertebrate microremains have been obtained from two calcar- eous spot samples (MT2 and MT6) collected and acid-leached by CS, in the Mt. Taccu area near San Nicolo ` Gerrei, southeast Sar- dinia (Fig. 3). The area, part of the Sardinian Massif, has a De- vonian sequence characterized by alternating meta-argillites and meta-limestones. The calcareous content increases up to the Late Devonian-Early Carboniferous massive limestone sequence. The lithostratigraphic unit known as Calcari a Clymenie ranges from Frasnian to Tournaisian (Corradini, 1998, 2003; Corradini et al., 2003). SYSTEMATIC PALEONTOLOGY Class CHONDRICHTHYES Huxley, 1880 Subclass ELASMOBRANCHII Bonaparte, 1838 Order PHOEBODONTIFORMES Ginter, Hairapetian and Klug, 2002 Family PHOEBODONTIDAE Williams in Zangerl, 1981 Genus THRINACODUS St. John & Worthen, 1875 Type species.Diplodus incurvus Newberry and Worthen, 1866. THRINACODUS TRANQUILLUS Ginter, 2000 Figure 4.1–4.2 Description.One relatively large (more than one millimeter) symmetrical tooth of Thrinacodus shows excellent preservation, with the cusp tips (two among three) being present. The crown consists of a straight main cusp and two lateral diverging ones (around 40°). Cusps are long, more than half the length of the base, slender, with ornamentation consisting of cutting edges and slight ridges on the lingual side of one cusp (Fig. 4.2). The angle between the base and the inclined crown is less than 30°.