TRANSACTIONS OF THE KANSAS ACADEMY OF SCIENCE Vol. 112, no. 1/2 p. 98-102 (2009) First record of Anomoeodus (Osteichthyes: Pycnodontiformes) from the Upper Cretaceous Niobrara Chalk of western Kansas KENSHU SHIMADA 1,2 AND MICHAEL J. EVERHART 2 1. Environmental Science Program and Department of Biological Sciences, DePaul University, 2325 N. Clifton Avenue, Chicago, Illinois 60614 - kshimada@depaul.edu 2. Sternberg Museum of Natural History, Fort Hays State University, Hays, Kansas 67601 - meverhar@fhsu.edu We describe the first occurrence of the Late Cretaceous pycnodont fish referred to Anomoeodus cf. A. barberi Hussakof, from the Smoky Hill Chalk Member of the Niobrara Chalk in western Logan County, Kansas. The specimen is an incomplete right prearticular tooth plate that was surface collected from the upper Smoky Hill Chalk (lower Campanian), and represents the second and the youngest occurrence of Anomoeodus from Kansas. The addition of this taxon to the fauna of the Smoky Hill Chalk increases the total number of pycnodont taxa to four, bony fish taxa to 56, and total fish taxa to 72. Keywords: Campanian, fossil fish, paleoecology, pycnodont, Smoky Hill Chalk INTRODUCTION In 1974, Jerome (Pete) Bussen, Wallace, Kansas, collected an unusual tooth bearing bone fragment in the Smoky Hill Chalk Member of the Niobrara Chalk of western Kansas. The fossil is identified as a tooth plate of Anomoeodus cf. A. barberi Hussakof, 1947, an extinct bony fish taxon belonging to the order Pycnodontiformes. The specimen described here is noteworthy because it represents the first record of Anomoeodus in the Smoky Hill Chalk of Kansas. SYSTEMATIC PALEONTOLOGY Class Osteichthyes Subclass Actinopterygii Superorder Neopterygii Order Pycnodontiformes Berg, 1937 Family Pycnodontidae Agassiz, 1833 Genus Anomoeodus Forir, 1887 Anomoeodus cf. A. barberi Hussakof, 1947 Figure 1A Material. FHSM VP-17319, an incomplete right prearticular, in the Vertebrate Paleontology collection of Sternberg Museum of Natural History at Fort Hays State University (FHSM), Hays, Kansas. Locality Western Logan County, Kansas; exact locality information is on file at FHSM. Stratigraphic horizon Near Hattin s (1982) Marker Unit 18 of the Smoky Hill Chalk Member of the Niobrara Chalk (Upper Cretaceous; lower Campanian). Description The specimen represents the posterior half of a damaged right prearticular where all peripheral margins represent broken surfaces. As preserved, the specimen is 26 mm and 27.5 mm in anteroposterior and mediolateral directions, respectively. Much of the occlusal surface is covered with teeth, whereas the entire basal face is represented by bone that exhibits a ridge running in an anteromedial-posterolateral direction. Four distinct, anteroposteriorly-arranged rows of smooth, rounded teeth are present. One of the rows consists of four (as preserved), large oblong teeth, each of which is oriented in
Transactions of the Kansas Academy of Science 112(1/2), 2009 99 distinct, anteroposteriorly-arranged rows of smooth, rounded teeth are present. One of the rows consists of four (as preserved), large oblong teeth, each of which is oriented in anteromedial-posterolateral direction and measure approximately 14 mm in major axis and 4.5 mm in minor axis (referred to main row here). Two rows of small (1-4 mm), circular to oval teeth (referred to lateral rows ) are present laterally to the main row, where each preserves six teeth (one tooth in the laterally located lateral row is missing its crown due to damage). There is another tooth row (referred to medial row ) medial to the main row. It preserves three, small (1-1.5 mm) oval teeth (one of which is damaged and missing its crown). The crowns of the teeth are low in lateral view, measuring slightly less than 1 mm in maximum height. Basal to the crown of each tooth is a columnar root that is deeply embedded in the prearticular bone. The maximum thickness of the specimen (occlusobasal height including both the teeth and prearticular bone) is 9.5 mm. Remarks. The size and arrangement of the teeth in FHSM VP-17319 (Fig. 1A) resemble the holotype and paratype specimens of Anomoeodus barberi (Fig. 1B, C) from the Marlbrook Marl (upper Campanian) in Arkadelphia, Arkansas, which are housed in the Field Museum of Natural History (FMNH) in Chicago, Illinois (see Hussakof, 1947). However, the teeth of the main row in FHSM VP-17319 are slightly more robust than those in the type specimens. Furthermore, in FHSM VP-17319, the teeth in the laterally located lateral row are much smaller than the teeth in the medially located lateral row, whereas the teeth between the two rows in both types are similar in size. These differences may be attributed to individual differences within this species. For example, the medial row in the paratype (Fig. 1C) consists of teeth that are smaller than those in the comparable tooth row in the holotype (Fig. 1B). The posterior tooth in the main row in the paratype is a single tooth, whereas that in the holotype is split into two. Thus, it appears that a considerable amount of tooth variation is present in A. barberi. However, because of the perceived differences between FHSM VP-17319 and the types of A. barberi, we conservatively refer FHSM VP-17319 to A. cf. A. barberi. DISCUSSION Anomoeodus is a pycnodont taxon that chronologically ranged from the Late Jurassic through the Eocene. Over 25 species of Anomoeodus have been described to date, although the majority of them are known only from isolated dental material (Kriwet, 2002; Poyato-Ariza and Wenz, 2002). Anomoeodus barberi is one such species, known only from dental plates. Besides the type specimens from the Marlbrook Marl of Arkansas (Hussakof, 1947; Fig. 1B, C), A. barberi has also been collected in several other localities in North America, including the Ozan Formation (middle Campanian) of Texas (McKinzie, 2002). Recently, Shimada (2006; see also Zielinski, 1994) reported a nearly complete left prearticular of A. barberi from the Blue Hill Shale Member (middle Turonian) of the Carlile Shale in Ellis County, Kansas (FHSM VP- 6728). Although its exact species-level taxonomic identification remains questionable, FHSM VP-17319 from the lower Campanian described here (Fig. 1A) represents the second and the youngest occurrence of Anomoeodus in Kansas. Three species of pycnodonts were previously known from the Smoky Hill Chalk of Kansas (Shimada and Fielitz, 2006; Everhart, 2007): Micropycnodon kansasensis (Hibbard and Graffham, 1941) (Pycnodontidae), Hadrodus marshi Gregory, 1950 (Pycnodontidae), and an undetermined species of Palaeobalistum Blainville, 1818 (Nursallidae Blot, 1987). Stewart (1990, p. 24) noted the occurrence of an undetermined pycnodont that is not Micropycnodon and is probably not Hadrodus. FHSM VP-17319 described here appears to be the basis of Stewart s (1990) statement (MJE
100 Shimada and Everhart Figure 1. Anomoeodus prearticulars (anterior to top). A. Right prearticular of A. cf. A. barberi Hussakof, 1947, from Smoky Hill Chalk Member of Niobrara Chalk, Logan County, Kansas, described here (FHSM VP-17319; from left to right = basal, occlusal, and lateral views); B. Left prearticular referred to A. barberi from Blue Hill Shale Member of Carlile Shale, Ellis County, Kansas (FHSM VP-6378; occlusal and basal views); C. Holotype (right prearticular) of A. barberi from Marlbrook Marl, Arkadelphia, Arkansas (FMNH P27078; occlusal view); D. Paratype (right prearticular) from Marlbrook Marl, Arkadelphia, Arkansas (FMNH P27079; occlusal view). Scale = 1 cm.
Transactions of the Kansas Academy of Science 112(1/2), 2009 101 pers. 2008 comm. with J. Bussen). The formal description of Anomoeodus cf. A. barberi (FHSM VP-17319) given here makes the total number of pycnodont species from the stratigraphic member four. This record also constitutes the fifty-sixth osteichthyan taxon and seventy-second fish taxon recognized in the Smoky Hill Chalk in Kansas (Shimada and Fielitz, 2006; Fielitz and Shimada, in press). Where pycnodonts are durophagous deep-bodied fishes (Nursall, 1996), the occurrence of Anomoeodus from the Smoky Hill Chalk provides a new insight into the marine paleoecology of the Niobrara fauna during the Campanian time in the Western Interior Sea. ACKNOWLEDGEMENTS We thank J. Bussen, who discovered the described Anomoeodus specimen and donated it to the Sternberg Museum of Natural History. We appreciate comments by H.-P. Schultze, University of Kansas, and John Bruner, University of Alberta, on an earlier version of the manuscript. K.S. thanks Lance Grande and Bill Simpson (FMNH) for access to the type specimens of A. barberi. LITERATURE CITED Agassiz, L. 1833 1843 [1833]. Recherches sur les poissons fossiles [5 volumes]. Imprimerie de Petitpierre, Neuchâtel et Soleure, 1798 pp. Berg, L.S. 1937. A classification of fish-like vertebrates. Bulletin de l Académie des Sciences de l U.R.S.S. Classe des Sciences mathématiques et naturelles 4:1277-1280. Blainville, H.de. 1818. Sur les ichthyolites ou les poissons fossils. Nouveau Dictionnaire d Histoire Naturelle, Paris 27:10-395. Blot, J. 1987. L ordre des Pycnodontiformes. Studi e Ricerche sui Giacimenti Terziari di Bolca, Museo Civico di Storia Naturale, Verona 5:1-211. Everhart, M.J. 2007. Remains of a pycnodont fish (Actinopterygii: Pycnodontiformes) in a coprolite; An upper record of Micropycnodon kansasensis in the Smoky Hill Chalk, western Kansas. Kansas Academy of Science, Transactions 110(1/2):35-43. Fielitz, C. and Shimada, K. In press. A new species of Apateodus (Teleostei: Aulopiformes) from the Upper Cretaceous Niobrara Chalk of western Kansas, U.S.A. Journal of Vertebrate Paleontology. Forir, H. 1887. Contributions à l étude du système crétacé de la Belgique. I. Sur quelques poissons et crustacés nouveaux ou peu connus. Annales de la Société Géologique de Belgique 14:25-56. Gregory, J.T. 1950. A large pycnodont from the Niobrara Chalk. Postilla 5:1-10. Hattin, D.E. 1982. Stratigraphy and depositional environment of Smoky Hill Chalk Member, Niobrara Chalk (Upper Cretaceous) of the type area, western Kansas. Kansas Geological Survey Bulletin 225:1-108. Hibbard, C.W. and Graffham, A. 1941. A new pycnodont fish from the Upper Cretaceous of Rooks County, Kansas. University of Kansas Quarterly Bulletin 27:71-77. Hussakof, L. 1947. A new pycnodont fish from the Cretaceous of Arkansas. Fieldiana: Geology 10(4):23-27. Kriwet, J. 2002. Anomoeodus pauciseriale, a new pycnodont fish (Neopterygii, Pycnodontiformes) from the White Chalk Formation (Upper Cretaceous) of Sussex, South England. Paläontologische Zeitschrift 76:117-123. McKinzie, M. 2002. Pictorial catalogue of Late Cretaceous fossil fishes from north Texas. Occasional Papers of the Dallas Paleontological Society 5:97-154. Nursall, J.R. 1996. Distribution and ecology of pycnodont fishes. pp. 115-124 in Arratia, G., and Viohl, G. (eds.), Mesozoic Fishes: Systematics and Paleoecology. Dr. Friedrich Pfeil, München.
102 Shimada and Everhart Poyato-Ariza, F.J. and Wenz, S. 2002. A new insight into pycnodontiform fishes. Geodiversitas 24:139-248. Shimada, K. 2006. Marine vertebrates from the Blue Hill Shale Member of the Carlile Shale (Upper Cretaceous: Middle Turonian) in Kansas. Bulletin of the New Mexico Museum of Natural History and Science 35:165-175. Shimada, K. and Fielitz, C. 2006. Annotated checklist of fossil fishes from the Smoky Hill Chalk of the Niobrara Chalk (Upper Cretaceous) in Kansas. Bulletin of the New Mexico Museum of Natural History and Science 35:193-213. Stewart, J.D. 1990. Niobrara Formation vertebrate stratigraphy. pp. 19-30 in Bennett, S.C. (ed.), Niobrara Chalk Excursion Guidebook. University of Kansas Museum of Natural History and the Kansas Geological Survey, KGS Open File Report 90-60. Zielinski, S.L. 1994. First report of Pycnodontidae (Osteichthyes) from the Blue Hill Shale Member of the Carlile Shale (Upper Cretaceous; Middle Turonian), Ellis County, Kansas. Kansas Academy of Science, Abstracts 13(44)