Muraenesox

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 : 28-30

“ Muraenesox ” barrytownensis sp. nov.

urn:lsid:zoobank.org:act:8DFE6B71-9C28-4560-BD89-202468E3A97C

Fig. 9A–C

Muraenesocidae indet. – Ebersole et al. 2019: 189, fig. 69e–f.

Diagnosis

OL/OH = 1.54. Otoliths triangular, thick, higher in the middle. Sulcus wide, not divided into ostium and cauda, with ostial channel at antero-dorsal corner.

Etymology

This species is named after its type locality.

Material examined

Holotype UNITED STATES OF AMERICA • Right otolith; Alabama, Barrytown; “upper” Lisbon Formation ; Fig. 9C ; IRSNB P 9971 .

Paratypes UNITED STATES OF AMERICA • 4 otoliths of which two are figured: Fig. 9A–B ; Texas, Stone City Bluff, Brazos River , “ Stone City beds”; IRSNB P 9969 – P 9970 .

Type locality and horizon

United States of America, Barrytown (Alabama), “upper” Lisbon Formation.

Dimensions of the holotype

Length = 8.40 mm; height = 5.37 mm; thickness = 2.08 mm.

Description

The otoliths are very robust, massive and thickset; they are triangular to trapezoid in shape, with the ventral rim much longer than the dorsal one. Their anterior and posterior parts are straight, and the ventral part is smoothly curved. The highest part of the otolith is in the middle, and is prominently extruding dorsally. The margins are smooth, except for the postero-dorsal rim which is largely undulated and expands dorsally. The inner face is slightly convex, and the outer face is nearly flat, but somewhat convex posteriorly. The sulcus is wide, overall straight and not distinctively divided into ostium and cauda; it opens broadly to the anterior end of the otolith where the crista inferior is not clearly marked. Additionally, there is an ostial channel at the antero-dorsal corner, a feature most evident in the holotype. A single large colliculum fills the entire sulcus, whose posterior end is bent ventrally. The cristae are well-developed but not ridge-like. The dorsal area just above the crista superior swells and the size of the dorsal area is larger than that of the ventral one.

Remarks

These otoliths are assigned to the muraenesocids on the basis of their sulcus configuration, which is extraordinarily wide with a broad ostial part and a ventrally bent caudal end. Although the generic allocation is not certain, the overall similarity is close to genera such as Cynoponticus and Muraenesox ( Nolf 2013: pl. 19; Schwarzhans 2019b: pl. 8 figs 9–13). Otoliths from the Piney Point Formation described as Muraenesox rhomboideus by Müller (1999) do not show the aforementioned muraenesocid features. Instead, the narrower sulcus and more pronounced ventral area of this species are typical congrid features, and these otoliths were synonymized with “ Conger ” websteri ( Frost, 1933) by Nolf (2013) (see below).

Stratigraphic and geographic distribution

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

Figures

Fig. 9. Fish otoliths from the US middle and upper Eocene. A–C. “Muraenesox” barrytownensis sp. nov. A–B. “Stone City beds”, Stone City Bluff, Brazos River, Texas, paratypes (IRSNB P 9969–9970). C. “Upper” Lisbon F., Barrytown, County Road 21, Alabama, holotype (IRSNB P 9971). D. Conger vetustus Frizzell & Lamber, 1962, “upper” Lisbon F., Coffeeville Landing, Alabama (IRSNB P 9972). E–F. Pseudophichthys texanus sp. nov., Weches F., Wall Farm 1, Texas. E. Paratype (IRSNB P 9973). F. Holotype (IRSNB P 9974). G–K. Pseudophichthys glaber (Koken, 1888). G–H. Wheelock M., Little Brazos River, Stenzel loc., Texas (IRSNB P 9975–9976). I–K. “Stone City beds”, Stone City Bluff, Brazos River, sample 2 from bed P, Texas (IRSNB P 9977–9979). 1 = ventral view; 2 = inner view. Scale bars = 1 mm.