Pycnodus, Agassiz, 1835

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: 152-154

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.3664274

persistent identifier

http://treatment.plazi.org/id/18174D41-FF12-FF36-FD0D-99E149E00B96

treatment provided by

Plazi

scientific name

Pycnodus
status

 

Pycnodus  sp.

Fig. 57View Fig A–L

Albula  sp. – Clayton et al. 2013: fig. 6i–j. — Maisch et al. 2016: fig. 2, 1–2.

Material examined

UNITED STATES OF AMERICA – Alabama • 20 isolated teeth; Claiborne Group; MSC 35773.1–8, MSC 37185View Materials, MSC 37912.1–2, MSC 38483.1–6, NJSM 24037, SC 2012.47.128, WSU 36, WSU CC 560.

Description

Taxon known in Alabama only from isolated teeth. Teeth measure up to 6.0 mm in greatest diameter. Teeth have an oval outline in occlusal view and have a convex occlusal surface. Teeth may also have a flat medial crown surface. Teeth have a thick enamel covering that is smooth and extends to the base of the crown. There is a large oval basal pulp cavity. The occlusal surface of worn teeth is punctate.

Remarks

Several species of Pycnodus  have been reported from Paleogene strata, including P. variabilis Stromer, 1905b  (also Stromer 1910); P. toliapicus Agassiz, 1843  ; and P. pellei Priem, 1902  . In Alabama the taxon is known only from isolated teeth, and intraspecific variation within the dentitions of this genus is poorly known. This factor, coupled with our small sample size (n =20), precludes a more precise taxonomic assignment. Clayton et al. (2013: fig. 6i–j) illustrated a Pycnodus  sp. tooth that was incorrectly identified as Albula  sp. Based on our Claiborne Group sample, teeth of Pycnodus  sp. can be differentiated from Albula  in having a more convex occlusal surface, thicker enameloid covering, and large basal pulp cavity. Additionally, worn Pycnodus  teeth are punctate. Inexplicably, Maisch et al. (2016) stated that their specimens of Albula  sp. were similar to material from Alabama reported by Clayton et al. (2013: fig. 6ij), but the specimen specifically referred to, incorrectly identified as Albula  , is actually Pycnodus  sp. Additionally, the tooth shown by Clayton et al. (2013) is practically identical to the Pycnodus  sp. tooth Maisch et al. (2016: fig. 2, 1–2) figured in their study.

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 at sites ACh-14 and ACov-11, and the basal Lisbon Formation at site ACov-11. Upper Ypresian to lower Lutetian, zones NP14 and NP15.

NJSM

New Jersey State Museum

WSU

Weber State University, Bird and Mammal Collection

Kingdom

Animalia

Phylum

Chordata

Class

Actinopterygii

Order

Pycnodontiformes

Family

Pycnodontidae

Loc

Pycnodus

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

Albula

Scopoli 1777
1777