A rare window into a back-reef fish community from the middle Miocene (late Badenian) Medobory Hills barrier reef in western Ukraine, reconstructed mostly by means of otoliths
Author
Schwarzhans, Werner
Natural History Museum of Denmark, Zoological Museum, Universitetsparken 15, 2100 Copenhagen, Denmark
Author
Klots, Oleksandr
Author
Ryabokon, Tamara
Author
Kovalchuk, Oleksandr
text
Swiss Journal of Palaeontology
2022
18
2022-11-17
141
1
1
35
http://dx.doi.org/10.1186/s13358-022-00261-3
journal article
10.1186/s13358-022-00261-3
1664-2384
11999827
Pshekharus yesinorum
Bannikov & Kotlyar,
2015
Figures 9d, e
,
10a–e
1966
Cantharus
?
tietzei
Schubert, 1906
—Smigielska: pl. 17, fig. 3.
2015
Pshekharus yesinorum
—Bannikov & Kotlyar: pl. 10, fig. 1; pl. 11, figs. 1–3 (fig. 2 represents an otolith found in situ).
2022?
Pagellus
sp.
—Brzobohatý, Zahradníkova & Hudáčková: pl. 3, fig. M, N.
Material
3 otoliths:
1 specimen
, Kozatskyi Yar NMNHU- P
PI 2577
,
2 specimens
, Shydlivshchyna,
NMNHU-P
PI 2578
;
1 isolated jaw tooth, Mlyntsi,
NMNHU-P
PI 2588
;
4 isolated jaw teeth, Shydlivshchyna,
NMNHU-P
PI 2589
.
Description of otoliths
(specimen of
Fig. 9d
) OL:OH = 1.65. Ventral rim regularly curved, rather smooth; dorsal rim intensely crenulated with pronounced postdorsal angle. Rostrum long, pointed, 21% of OL. Posterior tip pointed at same level as rostrum.
Inner face convex. Sulcus moderately long, deepened, slightly supramedian. OL:SuL = 1.3. Ostium ventrally widened, slightly shorter than cauda; cauda slightly flexed at tip. OsL:CaL = 0.9; OsH:CaH = 1.85. Ventral furrow indistinct, close to ventral rim of otolith; dorsal depression long, narrow, with crista superior to rear part of ostium and anterior part of cauda. Outer face flat to slightly concave, smooth except for some irregular radial furrows.
Description of teeth
In addition to otoliths, there is a series of small isolated jaw teeth (
Fig. 10a–e
) sharing sparid morphology (e.g.
Bannikov, 2010
;
Bannikov & Kotlyar, 2015
;
Gol’din et al., 2020
;
Šoster & Kovalchuk, 2016
) and tentatively assigned here to
Pshekharus yesinorum
. Most of these specimens (
Fig. 10a–d
) represent posterior molariform teeth with symmetrical or partially asymmetrical crowns, which are round at the base and have a smooth surface. Tere is a less-pronounced blunt hook at the tip of
one specimen
(
Fig. 10d
). Te specimen
NMNHU-P
PI
2589/4 (
Fig. 10e
) represents an anterior tooth, which is narrow conical proximally and flattened distally. Crown width in the specimens considered (
0.65– 1.10 mm
) is quite similar to each other despite their position in the jaw, while the crown height differs more substantially varying from
0.60 to 0.80 mm
for posterior teeth and being equal to 2.0 mm for the anterior tooth.
Fig. 10
Fish teeth from the studied localities:
a–e
Pshekharus yesinorum
Bannikov & Kotlyar, 2015
, isolated jaw teeth in lateral (a1, b1, c, d1, e) and dorsal view (a2, b2, d2), arranged in a sequence from distal to proximal positions.
f
Dasyatis
sp.
, anterior tooth in dorsal (f1), occlusal view (f2), profile (f3) and labial view (f4)
Discussion
Bannikov and Kotlyar (2015)
used jaw dentition as a distinguishing character for the definition of their new genus
Pshekharus
, in particular the long anterior teeth, which are canine-like and cylindrical, such as those figured in
Fig. 10e
. Te sequence of teeth represented here and their association with otoliths that are similar to the in situ find in
P. yesinorum
support the allocation of both teeth and otoliths to that species, which was originally described from the early Sarmatian s.l. of
Moldova
. However, the otoliths tend to be slightly more compressed with a deeper ventral rim (OL:OH =1.65 vs. 1.85–2.05) than those from the Sarmatian s.l. (
Bannikov & Kotlyar, 2015
), but these differences are considered to represent an expression of variability. Otoliths indicate that
P. yesinorum
may have been rather widely distributed in the Paratethys in the late Badenian/Konkian and Sarmatian s.l. Specimens identified as
Cantharus
?
tietzei
by
Smigielska (1966)
from the Pre-Carpathian Trough of
Poland
and?
Pagellus
sp.
by Brzobohatý et. al. (2022) from the Vienna Basin likely represent
P. yesinorum
.