Jacquhermania duponti ( Winkler, 1876 )

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 : 120-122

Jacquhermania duponti ( Winkler, 1876)

Fig. 43

Cestracion duponti Winkler, 1876: 17 , figs 1–3.

Raja aequilateralis Dartevelle & Casier, 1959: 329 , fig. 85, pl. 35, fig. 12. Raja duponti – Leriche 1905: 100 , pl. 4, figs 26–28.

Raja sp. – Dartevelle & Casier 1943: 177, pl. 11, fig. 15.

Dasyatis duponti – Cappetta 1972: 202 , pl. 4, figs 11–18.

Jacquhermania duponti – Cappetta 1982: 116 , pl. 1, figs 1–10. — Clayton et al. 2013: figs 5i–j.

Material examined

UNITED STATES OF AMERICA – Alabama • 28 isolated teeth; Claiborne Group ; ALMNH PV1993.2.337 (5 specimens), ALMNH PV1993.2.376 (8 specimens), MSC 37519, MSC 37553.1 – 3 , MSC 38463, MSC 38484, SC 2012.47.4, SC 2012.47.5, SC 2012.47.155 (2 specimens), SC 2012.47.157, WSU 11 , WSU 15 , WSU CC 502.2 , WSU CC 512 .

Description

Teeth do not exceed 1.5 mm in mesiodistal width. Crown cuspidate, triangular in labial, lingual and profile views. In oral view, labial face rather narrow, triangular and flanked by smooth edges; lingual face more extensive and very convex. Labial face concave along tooth height. All enameloid smooth. Crown overhangs the root labially, but root lobes extend beyond crown base laterally and lingually. Root bilobed with deep medial furrow, and convex, sub-triangular basal attachment surfaces.

Remarks

Jacquhermania Cappetta, 1982 is a monospecific genus, with the only named species being J. duponti ( Winkler, 1876) . This species was originally placed within the genus Cestracion by Winkler (1876), then later referred to Raja and Dasyatis by Leriche (1905) and Cappetta (1972), respectively. Cappetta (1982) discussed how the teeth examined by Leriche (1905) as Raja duponti actually represented two separate taxa, Coupatezia woutersi and Cestracion duponti , the latter of which was placed into a new genus, Jacquhermania .

Teeth of Jacquhermania are generally easy to distinguish from all other coeval batoids within the Lisbon Formation and Gosport Sand. The combination of a very convex lingual face, small and concave labial face flanked by smooth cutting edges, lack of lingual uvulae, smooth enameloid, and cuspidate crown separate Jacquhermania from “ Dasyatis ”, Aturobatis , “ Rhinobatos ”, and Hypolophodon , as well as the lateral teeth of the various members of the Myliobatidae . Two teeth from the Lisbon Formation, one of which was illustrated by Clayton et al. (2013) as Gymnura sp., are unusual in being very high highcrowned but otherwise similar to Jacquhermania in our sample. These two teeth have a weakly concave labial face flanked by lateral cutting edges, the labial crown foot is drawn out into mesial and distal projections, but there is a conspicuous medial embayment at the lingual crown foot. These specimens ( Fig. 43 E–I, N–R) could represent anteriorly located teeth and/or potentially a male morphological variant of Jacquhermania as indicated by Cappetta (1982).

Stratigraphic and geographic range in Alabama

The specimens in our sample were collected from the basal Lisbon Formation at site ACov-11, the basal Gosport Sand at site ACl-4, and the Gosport Sand at site ACl-15. Lower Lutetian to middle Bartonian, zones NP15 to NP17.

Figures

Fig. 43. Jacquhermania duponti (Winkler, 1876), teeth. A–D. SC2012.47.5, basal Lisbon Formation. A. Labial view. B. Lingual view. C. Mesial view. D. Basal view. E–I. MSC 38484, basal Lisbon Formation. E. Labial view. F. Lingual view. G. Mesial view. H. Oral view. I. Basal view. J–M. MSC 37519, Gosport Sand. J. Labial view. K. Lingual view. L. Distal view. M. Basal view. N–R. SC2012.42.4, basal Lisbon Formation. N. Labial view. O. Lingual view. P. Mesial view. Q. Oral view. R. Basal view. S–V. WSU AL15, basal Lisbon Formation. S. Labial view. T. Lingual view. U. Mesial view. V. Basal view. Labial at top in oral and basal views. Scale bars = 1 mm.