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
Myripristis
sp.
Fig. 69
Q–R
Weileria cajun
–
Frizzell & Lamber 1961: 20
, figs 6, 18–19.
Myripristis creola
–
Stringer 1977: 88–91
, pl. 1, fig. 1; 1986: 215.
Myripristis
sp. –
Stringer & Breard 1997: 565
. —
Breard & Stringer 1999: 135
.
“genus
Myripristidarum
”
cajun
–
Nolf & Stringer 2003: 4
, pl. 4, figs 1a–2b.
“
Myripristina
”
cajun
–
Nolf 2013: 80
, pl. 172.
Material examined
UNITED STATES OF AMERICA
–
Alabama
• 2 otoliths; GLS otolith comparative collection (
1 specimen
),
MSC
39047
.
Description
Two ablated specimens indicate
Myripristis
. Sagittae distinct in having scutiform shape; greatest length across the dorsal margin. Height/length ratios around 70-75%. Some margins appear coarsely crenulated. Dorsal margin is almost straight; indications of dorsal and posterodorsal domes. Posteroventral margin slants inward, almost straight down to ventral margin. Ventral margin very short, broadly and evenly rounded. Anteroventral margin slants almost straight down from dorsal margin to ventral margin. Inner face slightly convex, marked by conspicuous dorsal sulcus. Sulcus located almost entirely on dorsal margin. Sulcus consists of ostium, anterior cauda, and posterior cauda. Sulcus unevenly excavated, filled with colliculum. Ostium about one-half length of cauda; ostium appears subelliptical in shape. Anterior and posterior cauda areas of approximately equal length. Prominent caudal keel. Anterior part of cauda is filled with colliculum; posterior part of cauda deeply excavated, little colliculum. Outer face irregularly convex, sculptured. Posterior of outer face of many specimens marked by linear pustules merging into incised radial lines.
Remarks
The sulcus of the otoliths, consisting of an ostium and anterior and posterior cauda, is a specialized myripristid feature (
Frizzell & Lamber 1961
). The
Myripristis
sp. otoliths from the
Lisbon
Formation in
Alabama
are very similar to middle and late Eocene otoliths found in
Louisiana
,
Mississippi
, and
Texas
(
Stringer 1986
,
2016
;
Breard & Stringer 1995
,
1999
;
Stringer & Breard 1997
;
Nolf & Stringer 2003
).
Stratigraphic and geographic range in
Alabama
The two
Myripristis
sp. specimens were recovered from the “upper”
Lisbon
Formation at site ACh-7. Bartonian, zones NP16 and NP17.