Jefitchia claybornensis Frizzell & Dante, 1965

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 : 216-217

Jefitchia claybornensis Frizzell & Dante, 1965

Fig. 72 A–D

Otolithus (Sciaenidarum) claybornensis Koken, 1888: 283 , pl. 19, figs 1, 4.

Otolithus (Sciaenidarum) similis – Koken 1888: 284 , pl. 19, figs 10–11.

Jefitchia claybornensis – Frizzell & Dante 1965: 705 . — Stringer 1977: 99–101, pl. 1, fig. 15; 1979: 103, pl. 1, fig. 15. — Schwarzhans 1993: 26, figs 5–7. — Breard & Stringer 1995: 80.

“genus Sciaenidarum ” claybornensis – Müller 1999: 161 . — Nolf & Stringer 2003: 6, pl. 7, figs 1a–5.

“ Sciaenida ” claybornensis – Nolf 2013: 107 , pl. 281.

Material examined

UNITED STATES OF AMERICA – Alabama • 16 otoliths; GLS otolith comparative collection (12 specimens), MSC 39042.3 ; MSC 39042.7 , MSC 39049, MSC 39057 .

Description

Sagittae generally subpyriform to subquadrate in shape. Inner face smooth, convex, thickest at center. Adult specimens quite large, exceeding 15 mm long. Height/length ratios range from approximately 65– 82%. Margins smooth on adult specimens, finely crenulate on small specimens.Anterior margin rounded; dorsal margin very gently rounded. Dorsal dome usually present on larger specimens. Posterodorsal dome forms sharp, obtuse angle with posterior margin. Posterior margin somewhat variable, ranging from slightly rounded, straight, to slightly incurved. Ventral margin broadly, unevenly rounded. Very prominent heterosulcoid-type sulcus located on inner face. Ostium fairly narrow (about twice width of cauda), elongated. Ostium filled with colliculum, extends from anterior margin to approximately vertical midline. Anterior sides of ostium approximately parallel, whereas posterior sides slightly arched. Cauda narrow, (one-half width of ostium), with horizontal and downturned portions. Horizontal portion as long or longer than downturned portion. Downturned portion forms obtuse angle. Sides of downturned portion of cauda tend to arch outward slightly. Posterior end of cauda tapered, almost reaches ventral margin. Slightly depressed area located mainly above horizontal portion of cauda. Crista superior developed primarily on horizontal portion of cauda. Ventral furrow usually indistinct. Outer face concave, sculptured, highly undulating.

Remarks

Although Jefitchia claybornensis is similar to J. copelandi (see above), the otoliths can be distinguished by the more elongate outline (lower height/length ratios) of J. claybornensis , as well as the shorter downturned portion of the cauda and the angle of the downturned portion of the cauda (less than 90-degrees from horizontal, especially on larger specimens). A growth series of J. claybornensis is shown in Nolf & Stringer (2003: pl. 7, figs 1–5). Jefitchia claybornensis also shows some similarity to Sciaena intermedius (see above), but this species is easily distinguished by its more inflated ostium. In addition, the downturned portion of the cauda of S. intermedius is longer than on J. claybornensis .

Koken (1888) originally noted that Jefitchia claybornensis was very common at “Clayborne [Claiborne], Alabama.” The species is also known from Alabama (Lisbon Formation and Gosport Sand), Louisiana (middle Eocene Moodys Branch Formation, upper Eocene Yazoo Clay), Mississippi (middle Eocene Moodys Branch Formation, upper Eocene Yazoo Clay), and Texas (middle Eocene Weches Formation). Müller (1999: pl. 33, 16–21) described a new species of sciaenid, “genus aff. Umbrina ” eanesi, from the middle Eocene Piney Point Formation of Virginia, but the species is so similar to J. claybornensis that it is not possible to distinguish the two. Furthermore, it is believed that “genus aff. Umbrina ” eanesi actually represents variation within Jefitchia claybornensis .

Stratigraphic and geographic range in Alabama

This species was recovered from the “upper” Lisbon Formation at site ACh-8, the contact of the Lisbon Formation and Gosport Sand at site AMo-4, and while rare, also from the Gosport Sand at site ACl-4. Bartonian, zones NP16 and NP17.

Figures

Fig. 72. Claiborne Group, “upper” Lisbon Formation, otoliths. A–D. Jefitchia claybornensis Frizzell & Dante, 1965. A–B. MSC 39057. A. Inner face (right sagitta, juvenile). B. Dorsal view. C–D. MSC 39049. C. Inner face (right sagitta). D. Dorsal view. — E–F. Ekokenia eporrecta Frizzell & Dante, 1965, MSC 39048. E. Inner face (left sagitta). F. Dorsal view. Scale bars: A–D=2 mm; E–F=5 mm.