Albula eppsi White, 1931,

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: 161-163

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.3664304

persistent identifier

http://treatment.plazi.org/id/18174D41-FF25-FF0D-FD44-9D724FF80C1A

treatment provided by

Plazi

scientific name

Albula eppsi White, 1931
status

 

Albula eppsi White, 1931 

Fig. 60View Fig A–I

Albula eppsi Frost in White, 1931: 83  , figs 137–141.

Albula  sp. – Maisch et al. 2016 (partim): fig. 2.5–6 (non 7–8).

Material examined

UNITED STATES OF AMERICA – Alabama • 33 isolated teeth; Claiborne Group; MSC 37358.1–2, MSC 37541View Materials, MSC 37909.1–6, MSC 38445.2–24, NJSM 24039.

Description

Low-crowned teeth, circular occlusal outline; occlusal surface of unworn teeth nearly flat to convex. Crown enameloid thin, smooth, generally not reaching tooth base. Worn teeth flat, with occlusal surface often oblique to tooth height, triturating surface composed of dentine. Lateral tooth edges range from convex to parallel tapering. Tooth base flat; circular basal pulp cavity centrally located.

Remarks

Teeth exhibiting the morphology described above have traditionally been assigned to either Albula oweni Owen, 1845  or Albula eppsi Frost in White, 1931  . White (1931) differentiated these species based on tooth size, with small teeth measuring less than 2.0 mm in diameter being assigned to A. eppsi  and larger teeth to A. oweni  . Casier (1966), however, synonymized the two species and suggested that A. eppsi  represented the juvenile morphology of A. oweni  . Forey (1973), however, proposed that A. eppsi  and A. oweni  were distinct taxa, noting that teeth of an intermediate size between the two were unknown. Weems (1999) came to the same conclusion based on a sample from the lower Eocene Nanjemoy Formation in Virginia, which included two Albula  tooth plates bearing small teeth, indicating to him a small adult Albula  morphology coexisted with the larger Albula oweni  .

Our Albula  sample includes teeth ranging in diameter from 1.0 mm to nearly 9.0 mm. This size gradient contradicts the observations of Forey (1973), possibly indicating that the varying sizes are related to heterodonty and/or ontogeny within a single species. However, unlike the parasphenoids of extant Albula vulpes (Linneaus, 1758)  , where large medial teeth are flanked by smaller teeth that gradually decrease in size towards the plate margins (see Clothier 1950: fig. 22), teeth on A. oweni  parasphenoids only slightly decrease in size across the tooth plate (see Owen 1845: pl. 47, fig. 3; Woodward 1893: pl. 17). This suggests that within fossil members of Albula  , monognathic heterodonty is not the determining factor with regard to tooth size, but is instead related to ontogeny and/or interspecific variation.

Irrespective of size, our Albula  tooth sample includes two morphologies, including those with lateral sides that taper basally towards the pulp cavity, and those with lateral edges that are straight or weakly convex. Of the teeth that exceeded 5.0 mm in diameter, all have tapered lateral edges and are consistent in size with the type specimens for A. oweni  as illustrated by Owen (1845: pl. 47, fig. 3) and Casier (1966: pl. 13, fig. 4). Thus, we assigned all teeth with tapered edges to this taxon. Of the teeth with a diameter of less than 5.0 mm, all have straight and parallel lateral edges, or the edges were biconvex. These teeth appear conspecific to those described as Albula eppsi  by Weems (1999). This difference in tooth morphology suggests that two species of Albula  are indeed present within Claiborne strata in Alabama.

Although the teeth in our sample suggest that both A. eppsi  and A. oweni  are present, complications exist concerning the use of the name Albula eppsi  . White (1931) originally named this taxon based on numerous dental elements with teeth, an operculum, and 40 otoliths that were derived from the lower Ypresian London Clay in the UK. The dental elements and teeth were given the name Albula eppsi  while the otoliths, following the convention of the time regarding otolith-based species, was assigned to Otolithus (Albula) eppsi Frost in White (1931)  . Several years earlier, Priem (1908) erected the species Otolithus  (Trachini?) bellevoyei based on isolated otoliths collected from Thanetian deposits in France. Nolf (2013) recently determined that the Albula eppsi  otoliths were conspecific with the otolith-based Albula bellovoyei  , rendering the otoliths of the former a junior synonym of the latter. This creates a taxonomic dilemma for several reasons. First, both White (1931) and Casier (1966) reported two species of Albula  within the London Clay, A. oweni  and A. eppsi  , and their differing dental morphologies support that these are indeed two unique and valid species. The otoliths from the London Clay should therefore belong to one of these two species, rather than represent a third coeval species, A. bellovoyei  . Thus, if it could be conclusively determined that the otoliths are indeed associated with the A. eppsi  bony material, all should be referred to A. bellovoyei  . One the other hand, if it were determined that the otoliths belong to A. oweni  , A. bellovoyei  would be designated a junior synonym of A. oweni  because this latter species was named decades earlier, in 1845. Bearing these taxonomic issues in mind, we choose to assign the small Claiborne Group teeth described above to A. eppsi  as there is currently no definitive link between the teeth described by White (1931) and A. bellovoyei  otoliths.

Our reexamination of a tooth figured by Maisch et al. (2016: fig 2, 5–6) as Albula  sp. ( NJSM 24039) from the Tallahatta/ Lisbon contact at site ACh-14 shows it has convex lateral edges, and we identify it as Albula eppsi  . Furthermore, several specimens identified by Case (1994b: 142, pl. 1, figs 372–375) as A. eppsi  from the lower Eocene Tuscahoma Sand in Lauderdale County, Mississippi instead belong to Fisherichthys folmeri  (see Weems 1999; Cicimurri & Knight 2009).

Stratigraphic and geographic range in Alabama

The specimens in our sample were collected from the lower Tallahatta Formation at site ADl–1, the Tallahatta Formation at site AMo–8, the contact of the Tallahatta and Lisbon formations at site ACh-14, the basal Lisbon Formation at site ACov–11, and the basal Gosport Sand at site ACl–4. Upper Ypresian to middle Bartonian, zones NP14 to NP17.

NJSM

New Jersey State Museum

Kingdom

Animalia

Phylum

Chordata

Class

Actinopterygii

Order

Albuliformes

Family

Albulidae

Genus

Albula

Loc

Albula eppsi White, 1931

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

Albula eppsi Frost in White, 1931: 83

White E. I. 1931: 83