Gen. et sp.

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 : 180-182

Gen. et sp. indet.

Fig. 67

Material examined

UNITED STATES OF AMERICA – Alabama • 1 isolated tooth; Claiborne Group ; MSC 2402 .

Description

Teeth anteroposteriorly longer than wide, laterally compressed covered with thick enameloid. Anterior half of tooth wider than posterior half, resulting in pear-shaped occlusal outline. Indistinct cusp located anteriorly, posterior margin slopes towards edge of tooth. Blunt transverse ridge extends across cusp; cusp conspicuously lighter in color than remainder of tooth. Lateral surfaces of crown convex, exhibiting fine growth lines. Basal face rounded.

Remarks

MSC 2402 ( Fig. 67 ) appears to be conspecific with teeth belonging to the Balistidae as described by Tyler (1980) and Tyler & Santini (2002). Tyler & Santini (2002) noted that isolated teeth and jaw fragments have little taxonomic value because the majority of differential characteristics among the described fossil taxa are based on complete specimens, not isolated teeth. The only reported Eocene member of the Balistidae , Gornylistes prodigiosus Bannikov & Tyler, 2008 , was described from a nearly complete specimen from the middle Eocene of the Caucasus. Although the type description for this specimen mentions the number of teeth in the jaws, the tooth morphologies were not described nor were they illustrated.

The teeth of Balistidae are superficially similar to the pharyngeal teeth of the Eocene fish Eotrigonodon . However, teeth of Balistidae teeth differ by having convex lateral edges, as opposed to being mesiodistally compressed with flat lateral edges on the teeth of Eotrigonodon (see Ciobanu 2011: figs 5–10). Furthermore, the crown of Eotrigonodon teeth has smooth enameloid that lacks transverse growth lines, which are visible on the teeth of Balistidae .

Stratigraphic and geographic range in Alabama

The lone specimen in our sample was collected from the Gosport Sand at site ACh-21. Middle Bartonian, Zone NP17.

Figures

Fig. 67. Balistidae Risso, 1810, tooth. A–D. MSC 2402, Gosport Sand. A. Profile view. B. Basal view. C. Oral view. D. Anterior view. Anterior at left in A–C. Scale bar = 5 mm.