The Maragheh bovids (Mammalia, Artiodactyla): systematic revision and biostratigraphiczoogeographic interpretation
Author
Kostopoulos, Dimitrios S.
Author
Bernor, Raymond L.
text
Geodiversitas
2011
2011-12-31
33
4
649
708
http://dx.doi.org/10.5252/g2011n4a6
journal article
10.5252/g2011n4a6
1638-9395
5377377
Samokeros minotaurus
Solounias, 1981
(
Fig. 29
)
Samokeros minotaurus
Solounias, 1981: 127
, text-figs 39, 40
partim
.
Palaeoryx pallasi
–
Mecquenem 1925
: pl. 4, fig. 1.
Tragocerus amaltheus
–
Mecquenem 1925
: pl. 5, fig. 1.
Kostopoulos D. S. & Bernor R. L.
TABLE 20. — Upper tooth measurements (in mm) of
Samokeros minotaurus
Solounias, 1981
from Maragheh. For abbreviations see text.
MNHN.F.
|
MNHN.F.
|
MNHN.F.MAR3209
|
MAR1396
|
MAR3210
|
dex
|
sin
|
LPM |
112.07 |
110+ |
113.14 |
113.13 |
LP |
43.84 |
42.80 |
42.00 |
LM |
71.00 |
72.15 |
LP2 |
13.40 |
13.53 |
13.50 |
13.18 |
WP2 |
13.68 |
13.40 |
14.50 |
14.04 |
LP3 |
15.50 |
16.58 |
15.50 |
14.96 |
WP3 |
16.18 |
16.40 |
15.50 |
15.25 |
LP4 |
16.26 |
15.14 |
15.23 |
WP4 |
18.60 |
17.80 |
18.14 |
LM1 |
22.15 |
19.94 |
20.00 |
WM1 |
23.84 |
22.30 |
21.68 |
LM2 |
(24.6) |
27.67 |
26.50 |
26.73 |
WM2 |
24.60 |
24.16 |
24.14 |
LM3 |
27.66 |
27.70 |
28.24 |
WM3 |
25.74 |
23.26 |
25.00 |
24.50 |
TABLE 21. — Lower tooth measurements (in mm) of
Samokeros minotaurus
Solounias, 1981
from Maragheh. For abbreviations see text.
MNHN.F.
|
MAR3229
|
MAR3230
|
MAR3233
|
MAR2979
|
Lpm |
130.60 |
Lp |
52.17 |
52.17 |
Lm |
78.90 |
78.30 |
Lp2 |
14.40 |
14.66 |
Wp2 |
8.10 |
7.80 |
Lp3 |
18.50 |
18.53 |
Wp3 |
11.40 |
11.30 |
Lp4 |
19.16 |
21.00 |
19.11 |
19.18 |
Wp4 |
12.90 |
12.90 |
13.26 |
13.20 |
Lm1 |
20.50 |
19.78 |
21.30 |
Wm1 |
15.10 |
16.00 |
15.86 |
Lm2 |
25.30 |
25.50 |
25.40 |
Wm2 |
16.00 |
16.90 |
16.40 |
Lm3 |
34.50 |
35.20 |
Wm3 |
16.70 |
16.38 |
TYPE
LOCALITY. — Samos,
Greece
(late Miocene).
MATERIAL EXAMINED. — Part of cranium with broken horn-cores,
MAR1396
(
Mecquenem 1925
: pl. IV, fig. 1 as
P. pallasi
); palate, MAR3209 (
Mecquenem 1925
: pl.V, fig. 1 as
Tragocerus amaltheus
); P2-M3part, MAR3210 (labelled as
T. amalthea
); part of right mandibular ramus with p2-m3, MAR3229 (labelled as
P. pallasi
); part of right mandibular ramus with p4-m2, MAR3233 (labelled as
P. pallasi
?); part of left mandibular ramus with p4-m3, MAR3230 (labelled as
P. pallasi
?); part of left mandibular ramus with p2- p4,
MAR2979
.
DESCRIPTION AND REMARKS
Solounias (1981: 127)
erroneously referred the frontlet
MAR1323
(
Mecquenem 1925
: pl. VII, fig. 1) to his new genus and species
Samokeros minotaurus
; as it has been already shown this specimen belongs to the small heteronymous spiral horned antelope
Nisidorcas
.
Solounias (1981)
also provisionally ascribed to
S. minotaurus
the Maragheh frontlet AMNH27817, as well as, the cranium
MAR1396
originally referred by
Mecquenem (1925)
to
Palaeoryx pallasi
and discussed later by
Bohlin (1936)
and
Gentry (1971)
who thought it represents a large
Tragoportax
.
The overall cranial structure of
MAR1396
(
Fig. 29A, B
) is indeed very similar to that of
Tragoportax
but wider at the orbital level and with wider and low, box-like braincase that is more strongly bent on the face. It also differs in the supraorbital foramina placed into shallow depressions, the presence of a narrow triangular ethmoidal fissure defined by the nasals, frontals and lacrimals (but probably not by the maxillae), the inverse “U”-shaped fronto-nasal suture, the large and rather bilobed facial part of the jugal, the long and shallow lacrimal fossa with an additional small and round internal depression above the M2, the posterior position of the rather large infraorbital foramina (above P3), the more anteriorly opening choanae and the posterior position of posterior palatine foramina at the level of M3, the non elevated frontals, the much less developed rugose area restricted on the frontals and not limited posteriorly by the characteristic
Tragoportax
transverse bar, the presence of shallow frontal depressions behind the horn-cores, the elliptical basal cross-section of the horn-cores and the absence of keels on their preserved proximal part at least. Basic measurements of the cranium
MAR1396
are (in mm):
Wshc
= 136.5,
Wso
= 51.9,
Wbc
= 98.6,
Lfp-ocp
= 85.0,
Lfn-ocp
= 190.3,
DThcb
= 44.0,
APDhcb
= 63.0.
Dental morphology and dimensions of the MNHN.F sample also suggest important differences from other late Miocene boselaphines (
Tables 20
,
21
). Thus, the premolar row is significantly shorter (58-60% of the upper and
c.
66% of the lower molars instead of
c.
74% and 68-72% respectively in Maragheh
Tragoportax
), the P2 is short, squareshaped and bilobed lingually (
Fig. 29G, H
), the basal pillars are less common on the upper molars that bear central islets instead (
Fig. 29G, H
), the cement is rather abudant on the lower molars, the protoconid of p4 is pinched and both the p3 and the p4 are of primitive structure with widely open anterior valley and weak paraconid (
Fig. 29
D- F). The described dental material is of the size of
Palaeoryx
from the same locality, from which it differs in the much wider palate in front of P2, the much shorter P2, the narrower upper molars, the less developed paraconid of the p3 and p4, the thinner and longer metaconid of p3 and the weaker metastylid of the lower molars.
FIG. 29. —
Samokeros minotaurus
Solounias, 1981
from Maragheh and Samos:
A
,
B
, cranium (MNHN.F.MAR1396) from Maragheh in dorsal (
A
) and lateral (
B
) views;
C
, skull (AMNH23036) in lateral view;
D -F
, right mandibular ramus (MNHN.F.MAR3229) in occlusal (
D
), labial (
E
) and lingual (
F
) views;
G
, left toothrow of the cranium (MNHN.F.MAR1396) in occlusal view;
H
, right toothrow of the palate (MNHN.F.MAR3209) in occlusal view. Scale bars: 5 cm.
Kostopoulos D. S. & Bernor R. L.
The general morphological characters of the cranium
MAR1396
exhibit important differences with both
Tragoportax
and
Miotragocerus
from Maragheh and other Eurasian sites and indicate a taxon with more advanced characters. The opisthocranial morphology of
MAR1396
and the basal shape of the horn-cores are fully compatible with those of PIM99,
holotype
of
Samokeros minotaurus
. Additionally, PIM99 bears robust horn-cores similar to those of the frontlet AMNH27817 from Maragheh. The cranium and dental morphology, of
MAR1396
closely compare with those of the skull AMNH 23036 from Samos (
Fig. 29C
), which is referred to
Samokeros minotaurus
(
Kostopoulos 2009a: 373
)
. The p3 and p4 morphology of the latter specimen is also identical to that from Maragheh (
MAR2979
, 3229, 3230, 3233).