Ginglymostoma maroccanum Noubhani & Cappetta, 1997,

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, inclu, European Journal of Taxonomy 585, pp. 1-274: 20-22

publication ID

https://doi.org/10.5852/ejt.2019.585

publication LSID

lsid:zoobank.org:pub:181B6FBA-ED75-4BB4-84C4-FB512B794749

DOI

http://doi.org/10.5281/zenodo.3664500

persistent identifier

http://treatment.plazi.org/id/18174D41-FF96-FFBA-FE78-9A384E7C08DC

treatment provided by

Plazi

scientific name

Ginglymostoma maroccanum Noubhani & Cappetta, 1997
status

 

Ginglymostoma maroccanum Noubhani & Cappetta, 1997 

Fig. 7View Fig A–D

Ginglymostoma maroccanum Noubhani & Cappetta, 1997: 34  , pl. 10, fig. 2.

Ginglymostoma serra – Woodward 1889: 348  , pl. 16, fig. 9.

Material examined

UNITED STATES OF AMERICA – Alabama • 8 isolated teeth; Claiborne Group; MSC 34407.2, MSC 35752.1–7.

Description

Teeth with symmetrical crown and prominent median cusp. Median cusp tall, erect, and triangular, flanked by three pairs of lateral cusplets. Lateral cusplets decrease in size laterally. Labial crown face generally flat and smooth; a pair of low ridges is at times present that extends to the crown base. Labial face distally oriented with a shallow basal apron. Basal edge of the apron generally flat or slightly concave. Lingual crown face convex with a strong medial protuberance. Crown T-shaped in oral view. Lateral edges of the root extend beyond the base of the crown. Root base heart-shaped in basal view. Wide nutritive groove on root base that opens labially. Nutritive foramen is positioned within the lingual half of the nutritive groove. Prominent marginolingual foramen present on lingual root protuberance.

Remarks

Noubhani & Cappetta (1997) and Cappetta (2012) recognized five species of Eocene Ginglymostoma  including G. angolense Dartevelle & Casier, 1943  ; G. maghrebianum Casier, 1947  ; G. maroccanum Noubhani & Cappetta, 1997  ; G. serra Leidy, 1877  ; and G. sokotoense White, 1934  . The Ginglymostoma  teeth described above are all assigned to G. maroccanum  because they have no more than three pairs of lateral cusplets ( G. angolense  = six or more; G. serra  =five to nine; G. sokotoense  =five or more; G. maghrebianum  =two to six). Additionally, the Tallahatta Formation specimens have a pronounced apron that is either flat or slightly concave, as opposed to the shallow and rounded apron on G. angolense  . These teeth are similar to the Thanetian G. chenanei Noubhani & Cappetta, 1997  and Ypresian G. maghrebianum  , but differ by never having more than three pairs of lateral cusplets (as opposed to up to four pairs on G. chenanei  and five on G. maghrebianum  ). These teeth also differ from the Thanetian G. khourbgaense Noubhani & Cappetta, 1997  by having a shorter, and less triangular, median cusp and can be distinguished from the Danian G. subafricanum Arambourg, 1952  by having shorter and wider lateral cusplets. Because there appears to be a lack of variability regarding the number of cusplets on the teeth in our sample (only three pairs), these specimens are most appropriately assigned to G. maroccanum  .

It should also be noted that although G. serra  has been reported within the Paleogene by Dartevelle & Casier (1943) and Arambourg (1952), the species was originally erected by Leidy (1877) for teeth collected from South Carolina and is currently considered to be restricted to the Neogene (see Cappetta 2012). Woodward (1889), however, reported two G. serra  teeth from Alabama that were derived from upper Eocene Jackson Group deposits in Choctaw County. Upon reexamining these teeth, Leriche (1942), and later White (1956), reassigned them to Ginglymostoma obliquum ( Leidy, 1877)  based on the distal inclination of their crowns. Later, Case & West (1991) placed G. obliquum  within the genus Nebrius  because it has a crown morphology that is more typical of this latter genus. Thurmond & Jones (1981) compared the tooth illustrated by Woodward (1889: pl. 16: 9) to a suite of Ginglymostoma  teeth they collected from the Gosport Sand at site ACl- 4 in Clarke County, AL. Their analysis concluded with the designation of G. obliquum  as a junior synonym of G. serra  , and they stated that crown inclination is not a taxonomically viable characteristic but is instead related to heterodonty. Unfortunately, the identity of the Thurmond & Jones (1981) specimens remain a mystery as the teeth they discussed could not be located and the figures they provided (fig. 10) are reproductions of the original G. serra  type material illustrated by Leidy (1877), not their specimens from the Gosport Sand.

The Ginglymostoma  specimens in our sample were collected from the Ypresian portion of the lower Tallahatta Formation at site ADl-1. Ginglymostoma maroccanum  was originally described from Thanetian and Ypresian deposits in Morocco ( Noubhani & Cappetta 1997) and the stratigraphic overlap with our Tallahatta Formation specimens ( Fig. 7View Fig A–D) supports that they do indeed belong to this species. These specimens differ from a sample of Ginglymostoma  teeth collected from the Bartonian Gosport Sand at site ACl-4 ( Fig. 7View Fig E–H), the latter of which has up to four pairs of triangular lateral cusplets. The Bartonian teeth, assigned here to Ginglymostoma  sp., appear to represent a different species and are discussed in detail below.

Stratigraphic and geographic range in Alabama

Ginglymostoma maroccanum  specimens have been recovered only from the lower Tallahatta Formation at site ADl-1. Upper Ypresian, zones NP13 and NP14.

MSC

Michigan State University

Kingdom

Animalia

Phylum

Chordata

Class

Elasmobranchii

Order

Orectolobiformes

Family

Ginglymostomatidae

Genus

Ginglymostoma

Loc

Ginglymostoma maroccanum Noubhani & Cappetta, 1997

Ebersole, Jun A., Cicimurri, David J. & Stringer, Gary L. 2019
2019
Loc

Ginglymostoma maroccanum

Noubhani A. & Cappetta H. 1997: 34
Loc

Ginglymostoma serra –

Woodward A. S. 1889: 348