Before the freeze: otoliths from the Eocene of Seymour Island, Antarctica, reveal dominance of gadiform fishes (Teleostei)
Author
Schwarzhans, Werner
Ahrensburger Weg 103, D- 22359 Hamburg, Germany; & Natural History Museum of Denmark, Zoological Museum, Universitetsparken 15, DK- 2100 Copenhagen, Denmark;
Author
Mors, Thomas
Swedish Museum of Natural History, Department of Palaeobiology, P. O. Box 5007, SE- 10405 Stockholm, Sweden;
Author
Engelbrecht, Andrea
University of Vienna, Department of Palaeontology, Althanstrasse 14, 1090 Vienna, Austria;
Author
Reguero, Marcelo
Museo de La Plata, Division ́ Paleontolog ́ ıa de Vertebrados, Paseo del Bosque s / n, B 1900 FWA La Plata, Argentina
Author
Kriwet, Jurgen
University of Vienna, Department of Palaeontology, Althanstrasse 14, 1090 Vienna, Austria;
text
Journal of Systematic Palaeontology
2017
2016-03-16
15
2
147
170
http://dx.doi.org/10.1080/14772019.2016.1151958
journal article
10.1080/14772019.2016.1151958
1478-0941
PMC5221741
28077930
10883098
A30E5364-0003-4467-B902-43A41AD456CC
Cepola anderssoni
sp. nov.
(
Figs 5Q, R
,
6R
)
Material.
Holotype
:
NRM-PZ P.15996
(
Figs 5Q, R
,
6R
) (only
specimen
, broken into two halves during handling)
.
Occurrence.
Telm 5 unit; ‘
Natica
horizon’,
Cucullea
I member, La Meseta Formation, late Ypresian, early Eocene. Site IAA 2/95, Seymour Island,
Antarctica
.
Etymology.
Named in honour of Johan Gunnar Andersson, a Swedish pioneer of geological research in
Antarctica
.
Diagnosis.
OL:OH = 1.85. Dorsal rim shallow, with broadly rounded postdorsal angle. Rostrum sharp; posterior tip less sharp. OsL:CaL = 2.1;
OCL
:
CCL
= 2.0. Ostial colliculum reduced anteriorly, terminating at considerable distance from anterior rim of otolith. Outer face flat.
Description.
Otolith elongate, thin,
4.4 mm
long. OH:OT = 3.2. Dorsal rim shallow, gently curving, smooth, with broadly rounded postdorsal angle and highest at postdorsal angle. Ventral shallow, very regularly curving, highest at its middle, smooth. Rostrum long and sharp; dorsal margin of ostial opening regularly ascending without marked excisura or antirostrum. Posterior tip pointed, but considerably less sharply and projecting as rostrum.
Inner face convex with distinctly supramedian positioned narrow sulcus. Sulcus typically S-shaped with cauda being curved upwards from collum prior to terminating with an inferior tip. Ostium twice as long as cauda, slightly wider and narrower. Ostial colliculum not extending to opening of ostium to anterodorsal otolith rim. Collum ascending, wide, with feeble pseudocolliculum. Cauda very short, its small colliculum distinctly deepened. Dorsal depression large, well marked towards sulcus; ventral furrow feeble, running moderately distant from ventral rim of otolith. Outer face flat and smooth.
Figure 6.
Eocene otoliths from Seymour Island.
A,
Argentina antarctica
sp. nov.
, holotype, NRM-PZ P.15964, mirror imaged, inner face.
B, C,
Diaphus
?
marambionis
sp. nov., holotype, NRM-PZ P.15966;
B,
inner face;
C,
ventral view.
D—F,
Macruronus eastmani
sp. nov.
, holotype, NRM-PZ P.15970, mirror imaged;
D,
inner face;
E,
ventral view;
F,
outer face.
G—I,
Palimphemus seymourensis
sp. nov.
, holotype, NRM-PZ P.15973, mirror imaged;
G,
inner face;
H,
ventral view;
I,
outer face.
J—L,
Coelorinchus nordenskjoeldi
sp. nov.
, holotype, NRM-PZ P.15978;
J,
inner face;
K,
ventral view;
L,
outer face.
M, N,
Coelorinchus balushkini
sp. nov.
, holotype, NRM-PZ P.15976;
M,
inner face;
N,
ventral view.
O, P,
Hoplobrotula
?
antipoda
sp. nov., holotype, NRM-PZ P.15984, mirror imaged;
O,
inner face;
P,
ventral view.
Q,
Notoberyx cionei
gen. nov., sp. nov.
; holotype, NRM-PZ P.15987, inner face.
R,
Cepola anderssoni
sp. nov.
, holotype, NRM-PZ P.15996, mirror imaged, inner face.
Remarks.
Cepolid otoliths are well known from the Eocene of Europe represented by a number of species (see
Nolf 2013
). Of those,
Cepola excavata
(Stinton, 1978)
and
C. bartonensis
Schubert, 1916
resemble the proportions of the otolith (
Nolf 2013
;
Schwarzhans 2007
), while other species are more compressed (
C. densa
(Frost, 1934)
and
C. robusta
Nolf, 1988
).
Cepola anderssoni
differs from all those species by the anteriorly restricted ostial colliculum and the very small cauda.
Cepola yrieuensis
Steurbaut, 1984
from the early Oligocene of south-west
France
is similar in the short cauda, but differs in the distinct postdorsal angle (vs. rounded postdorsal region) and the ostial colliculum reaching to or close to the anterior rim (vs. anteriorly restricted).