Albula sp, Scopoli, 1777

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 : 186-187

Albula sp .

Fig. 69 A–B

Albula sp. – Stringer 1977: 63–65, pl. 1, fig. 1; 2016: 7, pl. 1: figs e–g, i, k. — Breard & Stringer 1995: 80; 1999: 135. — Stringer et al. 2001: 323. — Nolf & Stringer 2003: 4, pl. 1, fig. 2a–b.

Material examined

UNITED STATES OF AMERICA – Alabama • 4 otoliths; Claiborne Group ; GLS otolith comparative collection (3 specimens), MSC 562 .

Description

Sagittae quite large, one specimen exceeding 18 mm in length. Outline sub-elliptical; height/length ratios approximately 50–60%. Margins smooth; anterior margin very short, slightly arched. Dorsal margin almost straight, slopes downward anteriorly and posteriorly. Small, low posterodorsal dome forms highest point on dorsal margin. Posterior margin very short, subtruncate, bluntly pointed. Posteroventral margin short, almost straight, slightly curved inward or outward. Ventral margin very broadly rounded. Anteroventral margin almost straight, forms small, obtuse angle with anterior margin. Inner face conspicuously convex and twisted. Prominent sulcus developed in dorsal and posterior regions. Sulcus very long, extending from anterodorsal margin to posteroventral margin. Sulcus indistinctly divided, with downturned and flexed posterior. Ostium wide, long; length twice that of cauda. Ostium filled with colliculum, only slightly excavated. Ostium opens onto anterodorsal margin. Cauda with anterior sub-horizontal portion and posterior downturned portion. Anterior cauda separated from the cauda by a thickening and roughening of collicular material. Anterior cauda slightly excavated, posterior deeply excavated. Posterior cauda reaches posteroventral margin. Caudal keel present. Crista superior well developed, occurs as broad, raised ridge above cauda. Crista inferior absent. Ventral furrow not developed. The outer face concave, twisted, thin toward anterior, thickest in posterodorsal. Annual rings almost always visible on outer face.

Remarks

The posterior margin is commonly broken on the specimens available to us, but the Albula sp. from the Lisbon Formation is very similar to Albula sp. known from other Eocene deposits of the Gulf Coast ( Stringer 1977; Breard & Stringer 1995, 1999; Nolf & Stringer 2003). The Lisbon Albula sp. specimens are large, but late Eocene specimens from the Yazoo Clay in Louisiana are even larger, with some exceeding 25 mm (GLS, pers. observ.).

Stratigraphic and geographic range in Alabama

Specimens were recovered from the “upper” Lisbon Formation at site ACh-8. Bartonian, zones NP16 and NP17.

Figures

Fig. 69. Claiborne Group, “upper” Lisbon Formation, otoliths. A–B. Albula sp., MSC 562. A. Inner face (right sagitta). B. Dorsal view. — C–D. Pythonicthys colei (Müller, 1999), WSU CC 474. C. Inner face (left sagitta). D. Dorsal view. — E–F. Muraenesocidae Kaup, 1859, indet., MSC 39064. E. Inner face (left sagitta). F. Dorsal view. — G–H. Ariosoma nonsector Nolf & Stringer, 2003, MSC 39069. G. Inner face (left sagitta). H. Dorsal view. — I–J. Paraconger sector (Koken, 1888), MSC 39052. I. Inner face (right sagitta, broken on anterodorsal angle). J. Dorsal view. — K–L. Pseudophichthys sp., MSC 37059.2. K. Inner face (right sagitta). L. Dorsal view. — M–N. Rhynchoconger sp., MSC 37059.6. M. Inner face (left sagitta). N. Dorsal view. — O–P. Gnathophis meridies (Frizzell & Lamber, 1962), MSC 37059.XX. O. Inner face (right sagitta). P. Dorsal view. — Q–R. Myripristis sp., MSC 39047. Q. Inner face (right sagitta). R. Dorsal view. Scale bars: A–B =5 mm; C–R =2 mm.