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
Author
Ebersole, Jun A.
Author
Cicimurri, David J.
Author
Stringer, Gary L.
text
European Journal of Taxonomy
2019
2019-12-06
585
1
274
journal article
24105
10.5852/ejt.2019.585
dca608e8-fccf-4c1c-b8df-ef0c28e1d518
3660259
181B6FBA-ED75-4BB4-84C4-FB512B794749
Gnathophis meridies
(
Frizzell & Lamber, 1962
)
Fig. 69
O–P
“
Conger
”
meridies
Frizzell & Lamber, 1962
: figs 2a–b, 11a–d.
Paraconger meridies
–
Nolf 1985: 43
.
Gnathophis meridies
–
Nolf 2013
: pl. 22.
Material examined
UNITED STATES OF AMERICA
–
Alabama
• 4 otoliths; GLS otolith comparative collection (
3 specimens
),
MSC
37059
.
Description
Outline primarily oval with noticeable angularity. Length of sagitta is greater than height; height/ length ratios from approximately 60–72%. Margins smooth except for few small lobes on posterodorsal and posteroventral. Anterodorsal margin nearly straight; remaining dorsal and posterodorsal margins rounded.Anteroventral margin only slightly rounded; middle portion of ventral margin almost horizontal. Posteroventral margin rounded. Anterior more tapered than posterior. Prominent sulcus on inner face slants at approximately 45-degrees. Sulcus extends across approximately 75% of inner face. Dorsal and ventral margins of sulcus essentially parallel. Sulcus undivided, no defined ostium and cauda. Ostium does not quite reach anterior margin. Short, fairly wide ostial channel opens onto anterodorsal margin. Posterior of sulcus rounded. No depressed area above sulcus. Crista superior more pronounced than crista inferior. No ventral furrow. Outer face usually convex, thickest at center.
Remarks
Gnathophis meridies
is an uncommon component at its
type
stratum and locality, the lower Eocene Bashi Formation (Wilcox Group) in Meridian,
Mississippi
. This taxon is also uncommon in the Claiborne Group in
Alabama
. Species of
Gnathophis
lack a depressed area above the sulcus, a feature that occurs on most congrid otoliths. Although one of the specimens we examined is a juvenile and two specimens are fairly worn, they possess the salient characteristics indicative of
Gnathophis meridies
.
Stratigraphic and geographic range in
Alabama
Gnathophis meridies
is known only from the “upper”
Lisbon
Formation at site ACh-7. Bartonian, zones NP16 and NP17.