Paludicola 6(3):87-93 June 2007 © by the Rochester Institute of Vertebrate Paleontology NEW WESTERN HEMISPHERE OCCURRENCES OF SCHIZORHIZA WEILER, 1930 AND EOTORPEDO WHITE, 1934 (CHONDRICHTHYES, BATOMORPHII) James L. Knight1, David J. Cicimurri2, and Robert W. Purdy3, 1South Carolina State Museum, P.O. Box 100107, Columbia, South Carolina 29202 U.S.A., [email protected], 2Bob Campbell Geology Museum, 103 Garden Trail, Clemson, South Carolina 29634 U.S.A., [email protected], 3Department of Paleobiology, National Museum of Natural History, P. O. Box 37012, NHB, MRC121 Washington, District of Columbia 20013 U.S.A., [email protected] ABSTRACT A single rostral spine of Schizorhiza stromeri Weiler, 1930 was collected from a temporally mixed vertebrate assemblage recovered from Williamsburg County, South Carolina. Although well known from Upper Cretaceous strata of Africa, the South Carolina Schizorhiza occurrence represents one of the few records of the taxon from North America. In addition, our specimen is the northern-most Western Hemisphere occurrence, originating from approximately the same latitude as previous accounts from the Tethyan region of northern Africa. Eight teeth referable to Eotorpedo hilgendorfi (Jaekel, 1904) have thus far been recovered from Berkeley County, South Carolina. These specimens are important because they constitute the only evidence of Eotorpedo White, 1934 in the Western Hemisphere. Eotorpedo hilgendorfi could have reached South Carolina by following ocean currents from the Tethyan region down the western coast of Africa, across the Atlantic Ocean to the Caribbean, and northward to North America. INTRODUCTION paleofaunas of South Carolina, North America, and the Western Hemisphere in general. The majority of eastern United States Coastal A second site, in an active limestone quarry near Plain formations are of marine origin, and some of Jamestown, Berkeley County, South Carolina, has these units have proven to be rich sources of both late yielded an unexpectedly diverse vertebrate assemblage Mesozoic and early Cenozoic chondrichthyan remains that is dominated by elasmobranchs. Eotorpedo (i.e., Lawrence and Hall, 1987; Robb, 1989; Kent, hilgendorfi (Jaekel, 1904) is only one of the many 1999; Purdy et al., 2001). Recent investigations of important new records for the state, and the some of the marine units in South Carolina's Coastal composition of the Jamestown selachian assemblage Plain have shown interesting results, with the promise indicates a lower Eocene age for the deposit. of future opportunities to collect little-understood (or The purpose of this report is to illustrate the new completely unstudied) faunas from different late material, especially Eotorpedo hilgendorfi, and provide Mesozoic and Cenozoic time periods. a discussion of the paleobiology and paleogeographic One location, within the city limits of Kingstree, distributions of Schizorhiza and Eotorpedo. The Williamsburg County, South Carolina, has produced a specimens discussed in this report are housed in the mixed vertebrate assemblage containing Cretaceous, collections of the South Carolina State Museum (SC), Paleogene, and Neogene fossils (Breidis and Knight, Columbia, and the Bob Campbell Geology Museum 1996; Purdy, 1998). Among the fossils recovered from (BCGM), Clemson, South Carolina. Kingstree were the first South Carolina dinosaur remains, which were intermixed with broken teeth of METHODS Pleistocene horses and mastodonts. Several taxa found within this fauna, including Schizorhiza stromeri At the Kingstree site, members of the Myrtle Weiler, 1930, may be temporally constrained and thus Beach Fossil Club used 6 mm mesh sieves to screen provide significant data for understanding the wash matrix from the banks of a small creek feeding into the Black River. The fossiliferous deposit at the 87 88 PALUDICOLA, VOL. 6, NO. 2, 2007 Jamestown site is overlain by a thick section of 1948; Welton and Farish, 1993; Becker et al., 2006), limestone and is not exposed. However, some material U.S.A. is brought to the surface from a water-filled portion of Most sclerorhynchid rays, like Schizorhiza, were the quarry as drag-lines remove the limestone from similar to Recent sawsharks and sawfish in that they under 14+ m of water. JLK and DJC recovered matrix possessed an elongated, spined rostrum (Slaughter and from spoil piles for processing in the laboratory. The Springer, 1968; Tricas et al., 1997; Compagno and matrix was disaggregated in water and gently screen Last, 1999; Kirkland and Aguillón-Martinez, 2002; washed, with the finest sieve size being 0.25 mm. The Becker et al., 2003; Kriwet, 2004). Whereas rostral remaining concentrate was dried and sorted under a spines of extant sawfish are set in deep alveoli and are binocular microscope. not regularly replaced (Miller, 1974), rostral spines of Schizorhiza and sawsharks attach to the lateral margins SYSTEMATIC PALEONTOLOGY of the rostrum and are replaced throughout life (Slaughter and Springer, 1968; Kirkland and Aguillón- Order Sclerorhynchiformes Kriwet 2004 Martinez, 2002; Kriwet, 2004). Rostral spines of Family Sclerorhynchidae Cappetta 1974 Schizorhiza appear to be unique among Subfamily Schizorhizinae Kirkland and Aguillón- sclerorhynchids in their manner of replacement and Martinez 2002 arrangement on the rostrum. Kirkland and Aguillón- Schizorhiza Weiler 1930 Martinez (2002) have shown that new rostral spines Schizorhiza stromeri Weiler 1930 form between the widely flaring lobes of the peduncle Figure 1, A-B of the preceding spine (p. 20, fig. 5, p. 21, fig. 7), and spines were very closely packed on the rostrum (p. 21, Material SC 87.158.103, an isolated rostral fig. 6, p. 22, fig. 9). Because the rostral spines formed spine, Kingstree faunal assemblage, Williamsburg a continuous serrated edge, Kirkland and Aguillón- County, South Carolina (79°49'43" W lat., 33°40'16" N Martinez (2002) hypothesized that, rather than probing long.). the substrate for prey, Schizorhiza was an open water Description specimen highly ablated and predator that used its rostrum to slash at prey. incomplete, preserved length measures 10.1 mm; enameloid-covered crown much shorter than peduncle; Order Torpediniformes Buen 1926 crown dorsoventrally compressed, with smooth cutting Family Torpedinidae Bonaparte 1838 edges, asymmetrical diamond-shaped outline (anterior Eotorpedo White 1934 edge longer than posterior edge); base of crown Eotorpedo hilgendorfi (Jaekel 1904) narrows significantly where it joins peduncle; peduncle Figure 2, A-I bilobate, with widely diverging and dorsoventrally flattened dorsal and ventral lobes (one lobe broken Material BCGM 6894 - BCGM 6897, BCGM from just below base of crown); base of more complete 7026, SC 2006.16.1 - SC 2006.16.3, isolated teeth from lobe fluted. Martin Marietta Aggregates quarry near Jamestown, Remarks—Schizorhiza is chiefly known from Berkeley County, South Carolina (79° 40' 14" W lat., isolated rostral spines and two species, S. stromeri 33° 19' 43" N long.). (Weiler, 1930) and S. weileri (Serra, 1933), have been Description teeth with characteristic four-lobed described. Cappetta (1987) considers the genus to be appearance in occlusal view; flat-based crown monospecific, with S. weileri being a junior synonym dominated by tall, conical cusp; cusp strongly curved of S. stromeri. Although primarily known from rocks lingually; lower part of labial face bifurcates into of Maastrichtian age (Cappetta, 1987), Schizorhiza has widely diverging, basally curving lobes; wide medial been recovered from latest Campanian strata (Kirkland notch at lingual crown base; root apico-basally thin, and Aguillón-Martinez, 2002). The genus is well extends lingually past margin of crown, with large, documented in Africa, having been reported from centrally located basal foramen. Angola, Egypt, Libya, Morocco, Niger, Nigeria, Remarks Four species of Eotorpedo are Tunisia, and Zaire, (Weiler, 1930; Serra, 1933; currently recognized. Eotorpedo zennaroi Cappetta Darteville and Casier, 1943; Arambourg, 1952; 1988, from the lower Paleocene of Morocco, differs Cappetta, 1987, 1991). In the Middle East Schizorhiza from E. hilgendorfi (upper Paleocene to lower Eocene) has been identified in Iraq and Syria (Cappetta, 1987; in having a laterally compressed cusp with distinct Bardet et al., 2000). Previous reports of Schizorhiza labio-lingual cutting edges, and a conspicuous from the Western Hemisphere are very limited, with transverse labial ridge (Cappetta, 1988). Eotorpedo isolated reports from Mexico (Kirkland and Aguillón- jaekeli White 1934, from the upper Paleocene of Martinez, 2002; Gonzalez-Barba et al., 2004), Bolivia Nigeria, is similar to E. zennaroi in having a laterally (Cappetta, 1975), and Texas and Arkansas (Dunkle, compressed cusp with a labiolingually oriented cutting KNIGHT ET AL.—SCHIZORHIZA AND EOTORPEDO FROM NORTH AMERICA 89 edge. Teeth of E. jaekeli differ from E. hilgendorfi in taxon has been identified in Saudi Arabia (Madden et having much smaller labial crown lobes, and the al., 1995; Whybrow and Clemens, 1999). Eotorpedo is lingual root notch is narrower (White, 1934). deemed to be a relatively rare component of the Eotorpedo nolfi Herman 1974, from the lower Eocene Jamestown elasmobranch assemblage because only of Belgium, is based on a single tooth. The specimen eight teeth have thus far been recovered from the was distinguished primarily on the basis of its small hundreds of kilograms of matrix processed. size (estimated less than 3 mm in