Sciaena, (Koken, 1888)

Lin, Chien-Hsiang & Nolf, Dirk, 2022, Middle and late Eocene fish otoliths from the eastern and southern USA, European Journal of Taxonomy 814, pp. 1-122 : 90-92

“ Sciaena ” claybornensis ( Koken, 1888)

Fig. 32H–M

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

Jefitchia claybornensis – Frizzell & Dante 1965: 705. — Schwarzhans 1993: 26, figs 5–9. — Ebersole et al. 2019: 216 , fig. 72a–b, non 72c–d. — Stringer et al. 2022: 7, fig. 3j, non 3k

“genus Sciaenidarum ” claybornensis – Nolf 1985: 88; 2003: 8, pl. 3 figs 1–5. — Nolf & Stringer 2003: 6, pl. 7 figs 1–5.

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

Remarks

Based on the sulcus configuration, particularly the caudal part, “ S.” claybornensis and “ S.” eanesi, a much rarer species, might be more closely related. Their otoliths are characterized by a narrow ostium and a cauda which is straight in its anterior part. The end of the cauda is bent in a postero-ventral direction, but never curving forward. Admittedly, the differences between the otoliths of the two species are subtle, and Ebersole et al. (2019: 217) considered them to be synonyms. However, after examining more specimens in the collection, we recognized that they can still be separated by their outline shape and convexity of the inner face. The otoliths are more rounded and flatter in “ S.” claybornensis , while in “ S.” eanesi, two pronounced dorsal angles always exist in the middle and posterior part of the dorsal rim, and the latter angle further makes their posterior rim sharp in appearance. The otoliths of “ S.” eanesi also have a more convex inner face, which is most evident in their anterior portion. Moreover, otoliths of “ S.” claybornensis show an ontogenetic variation in the length of the cauda ( Nolf 2003: pl. 3 figs 1–5), which is not seen in “ S.” eanesi ( Fig. 34F–J ). It is also worth mentioning that Frizzell & Dante (1965) included “ S.” claybornensis in their fossil genus Jefitchia , together with the type species J. copelandi (see above), and this was followed as such by Schwarzhans (1993) and Ebersole et al. (2019). However, based on the diagnosis of the genus and the marked differences between J. copelandi and “ S.” claybornensis , we conclude that “ S.” claybornensis belongs to an unknown clade and Jefitchia is currently monospecific.

Stratigraphic and geographic distribution

Bartonian: Landrum Member, Texas; Cook Mountain Formation, Mississippi; “upper” Lisbon and Gosport Sand, Alabama; Moodys Branch Formation, Louisiana, Mississippi and Alabama. Priabonian: Yazoo Clay, Louisiana and Mississippi.

Figures

Fig. 32. Fish otoliths from the US middle and upper Eocene. A–G. Ekokenia eporrecta (Koken, 1888). A–B. Wheelock M., Little Brazos River, confluence with Brazos River, Texas (IRSNB P 10204–10205). C–G. “Stone City beds”, Stone City Bluff, Brazos River, sample 2, bed P, Texas (IRSNB P 10206– 10210). H–M. “Sciaena” claybornensis (Koken, 1888). H–K. Yazoo Clay, Copenhagen, Louisiana (IRSNB P 10211–10214). L–M. Moodys Branch F., Midway, Techeva Creek, Mississippi (IRSNB P 10215–10216). 1 = ventral view; 2 = inner view. Scale bars = 1 mm.

Fig. 34. Fish otoliths from the US middle and upper Eocene. A–E. Sciaena pseudoradians (Dante & Frizzell, 1965). A–C. Yazoo Clay, Copenhagen, Louisiana (IRSNB P 10225–10227). D. Yazoo Clay, Shubuta Clay M., Cynthia, Mississippi Lite clay pit, Mississippi (IRSNB P 10228). E. Moodys Branch F., Jackson, boring at the corner of Amite & Mill Streets, Mississippi (IRSNB P 10229). F–J. “Sciaena” eanesi (Müller, 1999). F. Gosport Sand, Little Stave Creek, Alabama (IRSNB P 10230). G. “Stone City beds”, Stone City Bluff, Brazos River, sample 2 from bed P, Texas (IRSNB P 10231). H–J. Piney Point F., Pamunkey River, Devil’s Hole, Virginia (loc. 19 of Müller), paratypes (IRSNB P 10232–10234). 1 = ventral view; 2 = inner view. Scale bars = 1 mm.