Lepophidium, Gill, 1895

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 : 201-202

Lepophidium ? mucronata ( Koken, 1888)

Fig. 70 M–N

Otolithus (Gadidarum) mucronatus Koken, 1888: 290 , 292, pl. 17, figs 10–11.

Otolithus (Gadidarum) mucronatus – Posthumus 1924: 13 .

Bauzaia mucronata – Frizzell & Dante 1965: 712–713 , pl. 86, figs 43–44.

“genus Lepophidiinorum ” mucronatus – Nolf 1980: 111 . — Breard & Stringer 1999: 135. — Müller 1999: 111, pl. 26, figs 14–20. — Nolf 2003: 4, pl. 1, figs 11–13.

“ Lepophidiinus ” mucronatus – Nolf 2013: 65 , pl. 125.

Material examined

UNITED STATES OF AMERICA – Alabama • 9 otoliths; GLS otolith comparative collection (6 specimens), MSC 39054, WSU CC 471.2 , WSU CC 471.3 .

Description

Sagittae primarily of oval shape, with prominent anterodorsal dome and sharply pointed posterior. Height/length ratios tending to 38–45%. Small, juvenile specimens exhibit very slight lobed margins; larger and adult specimens with smooth margins. Anterior margin fairly evenly rounded. Anterodorsal dome typically becoming more prominent on the larger specimens. Dorsal margin often slightly incurved between dome and posterodorsal slope. Posterodorsal slope straight and gentle. Posterior attenuated into well-developed tip or projection (except for very small specimens). Ventral margin broadly, nearly evenly rounded. Inner face smooth, only very slightly convex. Divided sulcus quite long, filled with colliculum, extending almost entire length of sagitta. Ostium usually about four times longer than cauda, widths approximately equal. Dorsal and ventral margins of ostium straight, parallel. Anterior portion of ostium rounded, almost touches anterior margin. Ostium separated from cauda by straight (sometimes slanted) incised line. Short cauda about same width as ostium, approximately rectangular in shape. Posterior of cauda rounded, almost touches the posterodorsal slope. Distinct crista superior, shallow but distinct, irregularly shaped depressed area above ostium. Ventral furrow absent to poorly developed. Outer face irregularly convex, commonly sculptured.

Remarks

Lepophidium ? mucronata is known from several Eocene (Claibornian) localities in Texas and Louisiana. The type stratum and locality for the species is the Lisbon Formation at site AMo- 4 in Monroe County, Alabama.

Stratigraphic and geographic range in Alabama

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

Figures

Fig. 70. Claiborne Group, “upper” Lisbon Formation, otoliths. A–B. Diretmus? cf. D. serratus (Müller, 1999), MSC 42212. A. Inner face (left sagitta). B. Anterior view. — C–D. Preophidion meyeri (Koken, 1888), MSC 39055. C. Inner face (right sagitta). D. Dorsal view. — E–F. Preophidion cf. P. petropolis Frizzell & Dante, 1965, MSC 42193. E. Inner face (right sagitta). F. Dorsal view. — G–H. Signata stenzeli Frizzell & Dante, 1965, MSC 39051. G. Inner face (left sagitta). H. Dorsal view. — I–J. Signata nicoli Frizzell & Dante, 1965, MSC 39046. I. Inner face (left sagitta). J. Dorsal view. — K–L. Hoplobrotula melrosensis (Frizzell & Dante, 1965), MSC 37059.3. K. Inner face (right sagitta). L. Dorsal view. — M–N. Lepophidium? mucronata (Koken, 1888), MSC 39054. M. Inner face (left sagitta). N. Dorsal view. — O–P. Gobiidae Cuvier, 1816, indet. MSC 39045. O. Inner face (left sagitta). P. Dorsal view. — Q–R. Bothidae Smitt, 1892, indet. MSC 42235. Q. Inner face (right sagitta). R. Dorsal view. Scale bars: A–P= 2 mm; Q–R =1 mm.