Conger ” biaculeatus

Lin, Chien-Hsiang, Steurbaut, Etienne & Nolf, Dirk, 2024, Early Eocene fish otoliths from the eastern and southern USA, European Journal of Taxonomy 935, pp. 203-240 : 214-216

“ Conger ” biaculeatus sp. nov.

urn:lsid:zoobank.org:act:644AE8C1-D8E8-471A-B0AC-054551C98BF0

Fig. 4D–H

Diagnosis

OL/OH = 1.8–1.9, OsL/CaL = 0.4–0.9. Small oval otoliths with salient and pointed rostrum and posterior rim. Wide sulcus, ostium opens widely to the antero-dorsal rim, cauda straight. Large colliculum visible in cauda.

Etymology

The species name biaculeatus alludes to the acuminated anterior and posterior rims of the otoliths.

Type material examined

Holotype UNITED STATES OF AMERICA • Left otolith; Alabama, Ozark, Bashi Formation ; Fig. 4D ; IRSNB P 10720.

Paratypes (13 in total) UNITED STATES OF AMERICA • 13 otoliths of which four are figured: Fig. 4E–H ; same collection data as for holotype; IRSNB P 10721 to P 10724 .

Type locality and horizon

United States of America, Ozark (Alabama), Bashi Formation.

Dimensions of the holotype

Length = 2.69 mm; height = 1.47 mm; thickness = 0.69 mm.

Description

The newly described species “ C. ” biaculeatus sp. nov. is characterized by oval-shaped otoliths with pointed anterior and posterior rims. The otoliths are moderately thick and have smooth margins, with slightly convex inner and outer faces. The deepest part of the otoliths is in their central part, where the ventral rim is slightly angled. The sulcus is wide and not well-divided into ostium and cauda, opening antero-dorsally on the anterior rim. A large colliculum fills the sulcus, which is more visible in the cauda. The ostial crista superior curves markedly upwards, and the caudal cristae are well-developed. The cauda is short, straight, and ends well before the posterior rim, while the crista inferior is almost straight without constriction. The size of the ventral area is comparable to the dorsal one.

Remarks

The sulcus type of “ C. ” biaculeatus is similar to that of other species under the incertae sedis genus, such as “ C. ” prolatus and “ C. ” websteri in Lin & Nolf (2022: figs 12d–g, 13a–c), which suggests that it may belong to an extinct taxon within the family Congridae .

Stratigraphic and geographic distribution

Ypresian: Bashi Formation, Alabama.

Figures

Fig. 4. Fish otoliths from the US lower Eocene formations. A. Ariosoma sp., Meridian, Red Hot Truck Stop, Bashi Fm., Mississippi (IRSNB P 10717). B–C. Paraconger meridies (Frizzell & Lamber, 1962), Rappahannock River, Potapaco Member, Virginia (IRSNB P 10718, P 10719). D–H. “Conger” biaculeatus sp. nov., Ozark, Bashi Fm., Alabama. D. Holotype (IRSNB P 10720). E–H. Paratypes (IRSNB P 10721 to P 10724). 1 = ventral view; 2 = inner view. Scale bars = 1 mm.