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
Author
Ebersole, Jun A.
Author
Cicimurri, David J.
Author
Stringer, Gary L.
text
European Journal of Taxonomy
2019
2019-12-06
585
1
274
journal article
https://doi.org/10.5852/ejt.2019.585
dca608e8-fccf-4c1c-b8df-ef0c28e1d518
3660259
181B6FBA-ED75-4BB4-84C4-FB512B794749
Gen. et sp.
indet
.
Fig. 61
A–H
Material examined
UNITED STATES OF AMERICA
–
Alabama
• 16 isolated teeth;
Claiborne Group
;
MSC
35778,
MSC
37242
,
MSC
37307.1
–
2
,
MSC
37391,
MSC
37515,
MSC
37654,
MSC
38443,
MSC
38444,
MSC
38488,
MSC
38532
,
WSU
CC 456
,
WSU
CC 488
(
3 specimens
),
WSU
CC 555
.
Description
Conical teeth up to 1.0 cm in height. Teeth sharply pointed, posteromedially curving, lack carinae. Crown enameloid thin, smooth, not extending to tooth base; apex solid and preserved with different color. Circular basal outline; deep conical pulp cavity. Enameloid often not preserved on lateral edges of the tooth, but almost always preserved at tooth apex.
Remarks
The teeth in our sample fall into two categories, including conical with a wide base, and elongate and cylindrical, with narrow base. The former morphology is similar to those of several Paleogene genera within the
Osteoglossidae
, including
Brychaetus
Agassiz, 1845
,
Phareodus
Leidy, 1873
, and
Ridgewoodichthys
Taverne, 2009
. These genera are largely differentiated by cranial and dental bones, and difficult to distinguish only from isolated teeth (see
Taverne 2009
: figs 3, 5). Because our sample consists only of isolated teeth, it is unclear if these two morphologies reflect heterodonty within a single species or represent multiple coeval species.As a result, all are herein assigned only to the
Osteoglossidae
.
Stratigraphic and geographic range in
Alabama
The specimens in our sample were collected from the lower Tallahatta Formation at site ADl-1, the contact of the Tallahatta and
Lisbon
formations and basal
Lisbon
Formation at site ACov-11, the “upper”
Lisbon
Formation at site ACh-8, the basal Gosport Sand at site ACl-4, and the Gosport Sand at site ACl- 15. Upper Ypresian to middle Bartonian, zones NP14 to NP17.