In the aftermath of Permian-Triassic boundary mass-extinction: new ostracod (Crustacea) genus and species from South Tibet
Author
Forel, Marie-Béatrice
Author
Crasquin, Sylvie
text
Geodiversitas
2011
2011-06-30
33
2
247
263
http://dx.doi.org/10.5252/g2011n2a3
journal article
7715
10.5252/g2011n2a3
52b03d71-cefc-44da-9b75-e7cc270ed280
1638-9395
4597109
790AC12D-10AA-4480-AD5B-BAA1A543C552
Bairdia jeancharlesi
Forel
n. sp.
(
Fig. 3
I-L)
TYPE MATERIAL
. —
Holotype
: one complete carapace (P6M2607;
Fig. 3J
);
paratype
: one complete carapace (P6M2603;
Fig. 3I
).
ETYMOLOGY. — Dedicated to Jean-Charles Forel, personal dedication.
MATERIAL
EXAMINED. — 26 complete carapaces and 1 single valve.
DIMENSIONS. — L =
435 to 1120 µm
; H =
260 to 680 µm
.
Holotype
: L =
453 µm
; H =
276 µm
.
Paratype
: L =
895 µm
; H =
535 µm
.
TYPE
HORIZON
. — Sample 06Ti08, unit IIIb, Tulong Formation, Smithian, Lower Triassic.
TYPE
LOCALITY
. — Tulong section, Southern
Tibet
.
OCCURRENCE. — Tulong section, southernTibet.Samples 06Ti04, 06Ti08, 06Ti21, 06Ti27-31, 06Ti35, Tulong Formation, units
III
,
V
and
VI
, Smithian to Anisian, Lower-Middle Triassic.
DIAGNOSIS. — A punctate species of
Bairdia
with faint overlap, AB and PB with quite small radius of curvature, PDB, BD and ADB straight at RV.
DESCRIPTION
RV: PDB, DB and ADB straight; AB regularly arched with maximum of curvature located in its middle; AVB and PVB regularly convex; VB concave
FIG. 3. — Specimens from Tulong section (
Tibet
), stored at the Pierre et Marie Curie University Collections (Paris,France):
A -E
,
Bairdia letangae
Forel
n. sp.
;
A
, holotype (P6M2595), right lateral view of a complete carapace;
B
, paratype (P6M2596), right lateral view;
C
, right lateral view of a broken carapace (P6M2597);
D
, right lateral view of a broken carapace (P6M2598);
E
, left lateral view of a
complete carapace (P6M2599);
F -H
,
Bairdia finalyi
(
Méhes, 1911
)
;
F
, right lateral view of a complete carapace (P6M2601);
G
, right lateral view of a complete carapace (P6M2602);
H
, right lateral view of a complete carapace (P6M2606);
I -L
,
Bairdia jeancharlesi
Forel
n. sp.
;
I
,
paratype
(P6M2603), right lateral view of a complete carapace;
J
,
holotype
(P6M2607), right lateral view of a complete carapace;
K
, right lateral view of a broken carapace (P6M2604);
L
, right lateral view of a complete carapace (P6M2605);
M
,
Spinocypris vulgaris
Kozur, 1971
, right lateral view of a complete carapace (P6M2600). Scale bars: 100 μm.
TABLE 1
. — Distribution chart and abundances of Lower and Middle Triassic ostracods in the Tulong section. The global extension of each species within the section is represented with grey parts. Abundances are indicated as follows: z, between 1 and
5 specimens
; Ƃ, between 5 and
10 specimens
; ¡, between 10 and
20 specimens
;
×
, more than
20 specimens
.
in its anterior part; PB with quite small radius of curvature but bairdoid beak poorly expressed. LV: PDB straight, DB regularly arched, ADB straight to gently arched, AB rounded with maximum of curvature in its middle; AVB, VB and PVB arched; PB with quite small radius of curvature. Carapace ornamented by small punctations, flattened laterally in posterior and anterior parts; overlap is small with maximum in anterior part of DB; H/L = 0.61.
REMARKS
Bairdia jeancharlesi
Forel
n. sp.
is close to
Bairdia cassiana rotundidorsata
Monostori, 1995
from the Anisian of Balaton area (
Hungary
;
Monostori 1995
). Here, the carapace is shorter, the overlap is weaker and the DB and PDB are more inclined posteriorly.