Ostracods (Crustacea) of the Early-Middle Permian (Cisarulian-Guadalupian) from Central Thailand (Indochina Block): Part II, Orders Podocopida, Platycopida and Myodocopida
Author
Chitnarin, Anisong
Author
Crasquin, Sylvie
Author
Forel, Marie-Béatrice
Author
Tepnarong, Prachya
text
Geodiversitas
2017
2017-12-29
39
4
651
690
http://dx.doi.org/10.5252/g2017n4a1
journal article
10.5252/g2017n4a1
1638-9395
4536112
urn:lsid:zoobank.org:pub:DB464417-3EA1-4C4E-9C03-624C1627969C
Bairdia incisedorsa
Chitnarin
,
n. sp.
(
Figs 3
E-F, I-J)
TYPE MATERIAL. —
Holotype
: one complete carapace (SUT-09-2216;
Fig. 3E
);
paratype
, one complete carapace (SUT-09-2215;
Fig.3F
).
ETYMOLOGY. — From diagnosis character.
MATERIAL EXAMINED. — Five complete and three incomplete carapaces.
DIMENSIONS. — H =
0.46-0.50 mm
, L =
0.85-0.90 mm
, H/L = 0.54-0.55,
Holotype
: H =
0.501 mm
, L =
0.901 mm
;
Paratype
: H = 0.469, L = 0.855.
H (mm) |
Bairdia khaokanaensis
Chitnarin
,
n. sp.
|
Paratype |
Holotype |
L (mm) |
TYPE
HORIZON. — Sample 07
PB
05-3, Ban Naen Sawan I section,
Tak
Fa Formation, Roadian, Middle Permian.
TYPE
LOCALITY. — Ban Naen Sawan I section (
15° 54’11’’N
,
100° 53’36’’E
),
Phetchabun Province
, Central
Thailand
.
OCCURRENCES. — Sample 07
PB
05-3, Ban Nean Sawan I section,
Phetchabun Province
,
Tak
Fa Formation, Middle Permian, Central
Thailand
.
DIAGNOSIS. — Species of
Bairdia
with robust carapace, strong overlap of LV over RV in dorsal region, hinge invaginated, AB with very small radius of curvature and maximum of convexity located very high, tapering PB with maximum of curvature located at mid H, slight overlap of LV on RV at AVB and PVB, dorsal view spindle-shaped.
FIG. 4. — Height (
H
)-length (
L
) diagram of
Bairdia khaokanaensis
Chitnarin
,
n. sp.
Scale bar: 100 µm.
H 9Amm)
|
Bairdia fontainei
Chitnarin
,9n.9sp.
|
Holotype
|
Paratypes
|
L9Amm) |
DESCRIPTION
Carapace robust; dorsal outline broadly arched, DB of RV convex, DB of LV, hinge short and strongly invaginated; ADB short and concave; anterior end tapered and pointing upward, located above mid H; AVB long and slightly convex, angle between AVB and VB is 120°; VB short, VB of RV concave, VB of LV slightly convex; PVB long and slightly convex, angle between PVB and VB is 155°; PB tapering and located at mid H; PDB long and concave; anterior, posterior, anteroventral and posteroventral regions flattened laterally; maximum H located at mid L; surface smooth; LV larger and strongly overlaps RV at dorsal and ventral borders, slightly overlaps at AVB and PVB; in dorsal view, carapace spindle-shaped, with median part inflated and extremities strongly flattened.
FIG. 5. — Height (
H
)-length (
L
) diagram of
Bairdia fontainei
Chitnarin
,
n. sp.
Scale bar: 100 µm.
REMARKS
Bairdia incisedorsa
Chitnarin
,
n. sp.
could be easily identifiable by its diagnostic characters. However, in lateral view, it is closed to
B. permiana
Hamilton, 1942
from the Guadalupian, Middle Permian of Texas (
Hamilton 1942
). The two species can be differentiated by dorsal characteristics and the lower H/L ratio of
B. incisedorsa
Chitnarin
,
n. sp.
The present species can be compared with
B. subleguminoides
Chen, 1987
from the Late Permian of South
China
(
Shi & Chen 1987
) but the latter species is more elongated with longer anterior part and DB more convex at RV.