Cylindracanthus rectus (Agassiz, 1843)

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 : 152

Cylindracanthus rectus (Agassiz, 1843)

Fig. 56 D–G

Coelorhynchus rectus Agassiz, 1843: 92 .

Cylindracanthus acus Cope, 1870: 294 .

Cylindracanthus rectus – Fowler 1911: 141 , fig. 87.

Cylindracanthus acus – Thurmond & Jones 1981: 107 .

Material examined

UNITED STATES OF AMERICA – Alabama • 46 isolated teeth; Claiborne Group ; ALMNH PV1985.87.41, ALMNH PV1985.87.42, ALMNH PV1985.87.43, ALMNH PV1985.87.44, ALMNH PV1985.87.45, ALMNH PV1985.87.46, ALMNH PV1985.87.47, ALMNH PV1985.87.48, ALMNH PV1985.87.49, ALMNH PV1985.87.50, ALMNH PV1992.28.3.1, ALMNH PV2000.1.43.10 (2 specimens), ALMNH PV2016.3.75, GSA-V718 (3 specimens), MMNS VP-8196 (3 specimens), MMNS VP-8232 (2 specimens), MSC 188.197 , MSC 37123.1 – 2 , MSC 37186.1 – 3 , MSC 37445, MSC 38835, MSC 38378, SC 2012.47.94 (8 specimens), WSU 5019 , WSU 5055 (6 specimens) .

Description

Rostra morphologically like Cylindracanthus ornatus but lack ventral tooth-bearing grooves.

Remarks

See Cylindracanthus ornatus above.

Stratigraphic and geographic range in Alabama

The specimens in our sample were collected the contact of the Tallahatta and Lisbon formations and the basal Lisbon Formation at site ACov-11, the “upper” Lisbon Formation at site ACl-3, and the basal Gosport Sand at site ACl-4. Lower Lutetian to middle Bartonian, zones NP14 to NP17.

Figures

Fig. 56. Cylindracanthus Leidy, 1856, rostra. A–C. Cylindracanthus ornatus Leidy, 1856, SC2012.47.153, basal Lisbon Formation. A. Ventral view. B. Cross–section. C. Close–up of denticle rows. — D–G. Cylindracanthus rectus (Agassiz, 1843). D–E. MSC 38378, “upper” Lisbon Formation. D. Cross–section. E. Lateral view. F–G. WSU 5019, basal Lisbon Formation. F. Cross–section. G. Lateral view. Scale bars: A–C =2 mm; D–G= 5 mm.