Signata stenzeli Frizzell & Dante, 1965

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 : 199-200

Signata stenzeli Frizzell & Dante, 1965

Fig. 70 G–H

Signata stenzeli Dante & Frizzell in Frizzell & Dante, 1965: 709–710 , pl. 88, figs 12, 16–17.

“genus Ophidiidarum ” stenzeli – Nolf 1980: 138 , pl. 20, fig. 7.

“ Ophidiida ” stenzeli – Nolf 2013: 65 , pl. 124.

Material examined

UNITED STATES OF AMERICA – Alabama • 6 otoliths; GLS otolith comparative collection (5 specimens), MSC 39051 .

Description

Sagittae primarily with ovate shape, height/length ratios tend around 65–70%. Specimens with smooth margins. Anterior margin broadly rounded. Anterodorsal slope fairly straight to slightly incurved, steep. Dorsal margin quite short. Posterodorsal slope slightly outcurved, longer, less inclined than anterodorsal slope. Posterior sharply rounded. Ventral margin broadly and nearly evenly rounded. Smooth inner face strongly convex or inflated near vertical midline, slopes toward margins. Extremely wide, undivided, long sulcus (approximately 95% of otolith length). Very fine incised line marks sulcus. Sulcus extending essentially from anterior margin to very near posterior margin. Very small ostial channel opens on anterior margin (seen on well-preserved specimens). Dorsal margin of sulcus well separated from dorsal margin; ventral margin of sulcus closer to ventral margin. Dorsal margin of sulcus strongly flexed upward near vertical midline of otolith. Ventral margin of sulcus also flexed upward near vertical midline, not as strongly as dorsal margin. Cristae not developed; no depressed area observed. Ventral furrow absent. Outer face shallow, irregularly concave, commonly sculptured with smooth bosses and rugosities, especially in dorsal area.

Remarks

Extensive studies of ophidiid otoliths indicate that Signata stenzeli does not correspond to any living species. The genus therefore is fossil-based, representing an extinct form. The genus appears to be most common in the Eocene (Claiborne Group) of the US Gulf Coastal Plain.

Stratigraphic and geographic range in Alabama

Signata stenzeli is known from the “upper” Lisbon Formation at sites ACh-8 and AMo-4. Bartonian, zones NP16 and NP17.

Figures

Fig. 70. Claiborne Group, “upper” Lisbon Formation, otoliths. A–B. Diretmus? cf. D. serratus (Müller, 1999), MSC 42212. A. Inner face (left sagitta). B. Anterior view. — C–D. Preophidion meyeri (Koken, 1888), MSC 39055. C. Inner face (right sagitta). D. Dorsal view. — E–F. Preophidion cf. P. petropolis Frizzell & Dante, 1965, MSC 42193. E. Inner face (right sagitta). F. Dorsal view. — G–H. Signata stenzeli Frizzell & Dante, 1965, MSC 39051. G. Inner face (left sagitta). H. Dorsal view. — I–J. Signata nicoli Frizzell & Dante, 1965, MSC 39046. I. Inner face (left sagitta). J. Dorsal view. — K–L. Hoplobrotula melrosensis (Frizzell & Dante, 1965), MSC 37059.3. K. Inner face (right sagitta). L. Dorsal view. — M–N. Lepophidium? mucronata (Koken, 1888), MSC 39054. M. Inner face (left sagitta). N. Dorsal view. — O–P. Gobiidae Cuvier, 1816, indet. MSC 39045. O. Inner face (left sagitta). P. Dorsal view. — Q–R. Bothidae Smitt, 1892, indet. MSC 42235. Q. Inner face (right sagitta). R. Dorsal view. Scale bars: A–P= 2 mm; Q–R =1 mm.