Paraconger sector ( Koken, 1888 )

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, including an analysis of otoliths, European Journal of Taxonomy 585, pp. 1-274 : 190-191

Paraconger sector ( Koken, 1888)

Fig. 69 I–J

Otolithus (Platessae) sector Koken, 1888: 292 , pl. 17, fig. 14.

Paraconger sector – Nolf 1985: 292 , pl. 17, fig. 14; 2003: 4, pl. 1, fig. 2a–b; 2013: 35–37, pl. 24. — Nolf & Stringer 2003: 7, pl. 2, figs 9a–10.

Paraconger americanus – Müller 1999: 70 , pl. 20, figs 11–17.

Material examined

UNITED STATES OF AMERICA – Alabama • 4 otoliths; GLS otolith comparative collection (3 specimens), MSC 39052 .

Description

Species characterized by massive otoliths; height approximately 75% of the length. Margins primarily smooth; anterior margin is rounded. Ostial rim slightly concave, posterodorsal rim displays only very slight concavity. Posterior noticeably tapered, often almost bluntly pointed. Anteroventral rim rounder, shorter than posteroventral rim; posteroventral rim straighter and longer. Very slight angularity along ventral rim, near center. Inner face mainly smooth, convex. Sulcus fairly wide, only slightly incised. Sulcus filled with colliculum; ostial channel present. No clear division of ostial and caudal portions of sulcus. Posterior end of sulcus with some ventral widening. No indication of ventral furrow. Outer face smooth, convex except for area near posterior end, where shallow dorsoventrally oriented depression is located.

Remarks

This species and Ariosoma nonsector (see above) were originally described as one species by Koken (1888), but Paraconger sector was separated by Nolf & Stringer (2003). Paraconger sector is distinguished from Ariosoma nonsector by its greater length compared to its height (more elongate) and a narrower sulcus. Like the previous taxon, P. sector has a middle-to-late Eocene range in Alabama, Louisiana, Mississippi, and Virginia in the USA, and it also occurs in lower Oligocene (Rupelian) strata of Alabama, Louisiana, and Mississippi.

Stratigraphic and geographic range in Alabama

This taxon is known from the “upper” Lisbon Formation at site ACh-8 and the basal Gosport Sand at site ACl-4. Bartonian, zones NP16 and NP17.

Figures

Fig. 69. Claiborne Group, “upper” Lisbon Formation, otoliths. A–B. Albula sp., MSC 562. A. Inner face (right sagitta). B. Dorsal view. — C–D. Pythonicthys colei (Müller, 1999), WSU CC 474. C. Inner face (left sagitta). D. Dorsal view. — E–F. Muraenesocidae Kaup, 1859, indet., MSC 39064. E. Inner face (left sagitta). F. Dorsal view. — G–H. Ariosoma nonsector Nolf & Stringer, 2003, MSC 39069. G. Inner face (left sagitta). H. Dorsal view. — I–J. Paraconger sector (Koken, 1888), MSC 39052. I. Inner face (right sagitta, broken on anterodorsal angle). J. Dorsal view. — K–L. Pseudophichthys sp., MSC 37059.2. K. Inner face (right sagitta). L. Dorsal view. — M–N. Rhynchoconger sp., MSC 37059.6. M. Inner face (left sagitta). N. Dorsal view. — O–P. Gnathophis meridies (Frizzell & Lamber, 1962), MSC 37059.XX. O. Inner face (right sagitta). P. Dorsal view. — Q–R. Myripristis sp., MSC 39047. Q. Inner face (right sagitta). R. Dorsal view. Scale bars: A–B =5 mm; C–R =2 mm.