Scomberomorus bleekeri ( Storms, 1892 )

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 : 175-176

Scomberomorus bleekeri ( Storms, 1892)

Fig. 64 J–R

Cybium (Enchodus) bleekeri Storms, 1892: 3 , pl. 1.

Sphyraena sp. – Thurmond & Jones 1981: fig. 103, right.

Scomberomorus bleekeri – Bannikov 1982: 135 .

Scomberomorus cf. stormsi – Clayton et al. 2013 : fig. 6d.

Scomberomorus sp. – Maisch et al. 2016: 9, fig. 2, 27–33.

Material examined

UNITED STATES OF AMERICA – Alabama • 150 isolated teeth; Claiborne Group ; ALMNH PV1985.87.4, ALMNH PV1985.87.5, ALMNH PV1992.28.33 (4 specimens), ALMNH PV1993.2.496a (2 specimens), ALMNH PV 2005.6 .436.2, MMNS VP-8234 (12 specimens), MSC 34670, MSC 35777.1 – 5 , MSC 37194.1.1–12, MSC 37194.3.1–17, MSC 37292, MSC 37368, MSC 37662.1 – 3 , MSC 37894, MSC 38431.1 – 2 , MSC 38540, MSC 38979, NJSM 24044 , NJSM 24323 , NJSM 24324 , SC 2012.47.95, SC 2012.47.96 (26 specimens), WSU 24 , WSU 5053 (43 specimens), WSU CC 546 (2 specimens) .

Description

Teeth measuring less than 6.0 mm high, 4.0 mm wide. Crown medially curved, biconvex; medial face more convex than lateral face; faces with thin layer of smooth enameloid. Crown bicarinate; carinae smooth, sharp, convex, not reaching tooth base. Tooth base thickened medially, D-shaped in basal view.

Remarks

We identified two Scomberomorus species in our Claiborne sample, S. bleekeri ( Storms, 1892) and S. stormsi ( Leriche, 1905) . The teeth of S. stormsi (see below) differ by being more elongated and gracile compared to S. bleekeri ( Kemp et al. 1990; Weems 1999), they occasionally bear longitudinal striations on their labial and lingual faces ( Casier 1946) and are more ovate in basal outline.

The teeth of Scomberomorus bleekeri differ from those of Palaeocybium in being asymmetrical in basal view (the carinae divide the crown into a thinner, weakly convex labial face and thicker, very convex lingual face), and by appearing slightly constricted basally due to the carinae stopping short of the tooth base. We consider the Scomberomorus material discussed by Clayton et al. (2013) and Maisch et al. (2016) to represent S. bleekeri . Thurmond & Jones (1981: fig. 47) figured three teeth which they assigned to Sphyraena sp., but our examination of these teeth revealed that the specimen shown in figure 47 (right) belongs to S. bleekeri .

Stratigraphic and geographic range in Alabama

The specimens in our sample were collected from the lower Tallahatta Formation at site ADl-1, the Tallahatta Formation at site AMo-8, the contact of the Tallahatta and Lisbon formations at sites ACh-7, ACh-14 and ACov-11, the basal Lisbon Formation at site ACov-11, and the basal Gosport Sand at site ACl-4. Upper Ypresian to middle Bartonian, zones NP14 to NP17.

Figures

Fig. 64. Palaeocybium proosti (Storms, 1897) and Scomberomorus Lacépède, 1802, teeth. A–I. Palaeocybium proosti A–C. MSC 37194.4, Tallahatta/Lisbon formation contact zone, courtesy of T. Prescott Atkinson. A. Lingual view. B. Carinal view. C. Basal view. D–F. MSC 37423, basal Gosport Sand. D. Lingual view. E. Carinal view. F. Basal view. G–I. MSC 38500.2, basal Gosport Sand. G. Lingual view. H. Carinal view. I. Basal view. — J–R. Scomberomorus bleekeri (Storms, 1892). J–L. MSC 37147, Tallahatta/Lisbon formation contact zone, courtesy of James Lowery. J. Lingual view. K. Carinal view. L. Basal view. M–O. MSC 35777.2, basal Gosport Sand. M. Lingual view. N. Carinal view. O. Basal view. P–R. MSC 37268.1, basal Lisbon Formation. P. Lingual view. Q. Carinal view. R. Basal view. — S–AA. Scomberomorus stormsi (Leriche, 1905). S–U. MSC 37512.1, basal Gosport Sand. S. Lingual view. T. Carinal view. U. Basal view. V–X. MSC 37126, Tallahatta/Lisbon formation contact zone, courtesy of James Lowery. V. Lingual view. W. Carinal view. X. Basal view. Y–AA. MSC 38974.1, lower Tallahatta Formation. Y. Lingual view. Z. Carinal view. AA. Basal view. Scale bars = 2 mm.