Elopothrissus bernardlemorti, Lin & Nolf & Steurbaut, 2022

Lin, Chien-Hsiang & Nolf, Dirk, 2022, Middle and late Eocene fish otoliths from the eastern and southern USA, European Journal of Taxonomy 814, pp. 1-122 : 24-26

Elopothrissus bernardlemorti sp. nov.

urn:lsid:zoobank.org:act:EC4517DA-4346-4D6D-9875-6D79D11AA044

Fig. 8C–D

Diagnosis

OL/OH = 2.21–2.47, OsL/CaL = 0.43–0.55. Otoliths very elongate, thin, higher in the middle. Oval ostium with colliculum. Elongate cauda of about ½ OL with crest like crista superior.

Etymology

This species is named after the owner, Bernard Lemort, of the bar L’Espérance near the IRSNB where many innovative discussions have taken place among researchers, with excellent drinks, continuously inspiring the authors.

Material examined

Holotype UNITED STATES OF AMERICA • Right otolith; Texas, Alabama Ferry ; “Stone City beds”; Fig. 8C ; IRSNB P 9959 .

Paratypes UNITED STATES OF AMERICA • 5 otoliths, of which one is figured: Fig. 8D ; Texas, Stone City Bluff, Brazos River ; “Stone City beds” ; IRSNB P 9960 .

Type locality and horizon

United States of America, Alabama Ferry (Texas), “Stone City beds”.

Dimensions of the holotype

Length = 8.20 mm; height = 3.68 mm; thickness = 1.27 mm.

Description

This species is characterized by thin, very elongate otoliths which are obtuse at both ends, but the anterior one is more pointed. The deepest part of the otoliths is in their central part, which feature is most evident in the holotype. All the margins are smooth. The inner face is very slightly convex and the outer face is nearly flat. The sulcus is well-divided into ostium and cauda and opens widely antero-dorsally on the anterior rim. A large and oval ostial colliculum fills the ostium. The ostial crista superior curves markedly upwards. The cauda is long and straight, without colliculum. The caudal crista superior is more developed than the crista inferior and markedly constricted and ventrally bent in the posterior part. The crista inferior is almost straight without constriction. The ventral area is larger than the dorsal one.

Remarks

The otoliths of this new species are clearly different from those of the more commonly co-occurring Pterothrissus umbonatus ( Koken, 1884) (see below) by their slender appearance. Schwarzhans (1981a) indicated Pterothrissus protensus Stinton, 1975 , a junior synonym of Pterothrissus tardinensis (Leriche, 1908) (see Nolf & Rundle 2018: 19), as the type species of Elopothrissus . The otoliths of E. tardinensis are thicker and much more convex on the outer face than those of E. bernardlemorti sp. nov.

Stratigraphic and geographic distribution

Lutetian: “Stone City beds”, Texas. Bartonian: “upper” Lisbon Formation, Alabama.

Figures

Fig. 8. Fish otoliths from the US middle and upper Eocene. A–B. Albula sp. (IRSNB P 9957–9958). A. Weches F., Wall Farm 2, Texas. B. “Stone City beds”, Alabama Ferry, on Trinity River, North, Texas. C–D. Elopothrissus bernardlemorti sp. nov., “Stone City beds”, Texas. C. Alabama Ferry, on Trinity River, North, holotype (IRSNB P 9959), D. Stone City Bluff, Brazos River, sample 2 from bed P, paratype (IRSNB P 9960). E–H. Pythonichthys colei (Müller, 1999). E–F. Landrum M., Pin Oak Creek, Texas (IRSNB P 9961–9962). G–H. “Stone City beds”, Stone City Bluff, Brazos River, Texas (IRSNB P 9963–9964). I–L. Pterothrissus umbonatus (Koken, 1884), “Stone City beds”, Stone City Bluff, Brazos River, sample 2 from bed P, Texas (IRSNB P 9965–9968). M–N. Alaconger fornicatus (Frizzell & Lamber, 1962), Shubuta Clay M., Cynthia, Mississippi Lite clay pit, Mississippi (IRSNB P 10005–10006). 1 = ventral view; 2 = inner view. Scale bars = 1 mm.