Gen. et sp. indet, Bonaparte, 1832

Ebersole, Jun A., Cicimurri, David J. & Stringer, Gary L., 2019, Taxonomy and biostratigraphy of the elasmobranchs and bony fishes (Chondrichthyes and Osteichthyes) of the lower-to-middle Eocene (Ypresian to Bartonian) Claiborne Group in Alabama, USA, including an analysis of otoliths, European Journal of Taxonomy 585, pp. 1-274 : 164

Gen. et sp. indet .

Fig. 61 A–H

Material examined

UNITED STATES OF AMERICA – Alabama • 16 isolated teeth; Claiborne Group ; MSC 35778, MSC 37242, MSC 37307.1 – 2 , MSC 37391, MSC 37515, MSC 37654, MSC 38443, MSC 38444, MSC 38488, MSC 38532, WSU CC 456 , WSU CC 488 (3 specimens), WSU CC 555 .

Description

Conical teeth up to 1.0 cm in height. Teeth sharply pointed, posteromedially curving, lack carinae. Crown enameloid thin, smooth, not extending to tooth base; apex solid and preserved with different color. Circular basal outline; deep conical pulp cavity. Enameloid often not preserved on lateral edges of the tooth, but almost always preserved at tooth apex.

Remarks

The teeth in our sample fall into two categories, including conical with a wide base, and elongate and cylindrical, with narrow base. The former morphology is similar to those of several Paleogene genera within the Osteoglossidae , including Brychaetus Agassiz, 1845 , Phareodus Leidy, 1873 , and Ridgewoodichthys Taverne, 2009. These genera are largely differentiated by cranial and dental bones, and difficult to distinguish only from isolated teeth (see Taverne 2009: figs 3, 5). Because our sample consists only of isolated teeth, it is unclear if these two morphologies reflect heterodonty within a single species or represent multiple coeval species.As a result, all are herein assigned only to the Osteoglossidae .

Stratigraphic and geographic range in Alabama

The specimens in our sample were collected from the lower Tallahatta Formation at site ADl-1, the contact of the Tallahatta and Lisbon formations and basal Lisbon Formation at site ACov-11, the “upper” Lisbon Formation at site ACh-8, the basal Gosport Sand at site ACl-4, and the Gosport Sand at site ACl- 15. Upper Ypresian to middle Bartonian, zones NP14 to NP17.

Figures

Fig. 61. Osteoglossidae Bonaparte, 1832 and Ariidae Berg, 1958, elements. A–H. Osteoglossidae. A–B. Tooth, MSC 35778.1, lower Tallahatta Formation. A. Lingual view. B. Basal view. C–D. Tooth, MSC 38444, Tallahatta/Lisbon formation contact zone, courtesy of James Lowery. C. Lateral view. D. Basal view. E–F. Tooth, MSC 37515, basal Gosport Sand. E. Lingual view. F. Basal view. G–H. Tooth, MSC 37307.1, basal Lisbon Formation. G. Lingual view. H. Basal view. — I–Q. Ariidae. I–L. Pectoral spine, MSC 37122, Tallahatta/Lisbon formation contact zone, courtesy of Bruce Relihan. I. Anterior view. J. Posterior view. K. Lateral view. L. Transverse section. M–O. Pectoral spine, MSC 2398, Gosport Sand. M. Anterior view. N. Dorsal view. O. Posterior view. P–Q. Pectoral spine, MSC 37111, Tallahatta/Lisbon formation contact zone, courtesy of Bruce Relihan. P. Lateral view. Q. Posterior view. Scale bars: A–H=2 mm; I–Q=1 cm.