Ceratobairdia, Sohn, 1954

Zazzali, Sindbad, Crasquin, Sylvie, Deconinck, Jean-François & Feng, Qinglai, 2015, Biodiversity across the Guadalupian-Lopingian Boundary: first results on the ostracod (Crustacea) fauna, Chaotian section (Sichuan Province, South China), Geodiversitas 37 (3), pp. 283-313 : 294-300

Ceratobairdia ? ambigua Ishizaki, 1964 ( Fig. 6 A-C)

Ceratobairdia ? ambigua Ishizaki, 1964: 155, pl.19, fig. 6a, b (non figs 7, 8).

Bairdia guangxiensis Guan in Guan et al., 1978: 154, pl. 38, figs 3, 4. — Wang 1978: 291 pl. 3, fig. 5. — Chen & Shi 1982: 122, pl. 5, fig. 17. — Wei et al. 1983: 56, pl. 15, fig. 6. — Chen & Bao 1986: 114, pl. 3, figs 7, 8. — Shi & Chen 1987: 31, pl. 3, figs 1-9; 2002: 67, pl. 5, figs 1-9; pl. 28, figs 1, 2.

Bairdia fujisan Tanaka & Maeda in Tanaka et al., 2012: 96, fig. 6.3.

Bairdia nishiwakii Tanaka & Nishimura in Tanaka et al., 2013: 297, fig. 8.1 (non fig. 2).

MATERIAL EXAMINED. — Five complete carapaces, ten broken carapaces, five isolated valves and three broken valves.

DIMENSIONS. — L= 1020-1570 µm; H= 666-974 µm.

OCCURRENCES. — Kitakami Massif, North-East Japan, Middle Permian ( Ishizaki 1964); Guangxi Province, China, Late Permian ( Guan et al. 1978); Guizhou province, China, Late Permian ( Wang 1978); Jiangsu Province, China, latest Permian ( Chen & Shi 1982); Guizhou Province, China, Late Permian ( Wei et al. 1983); Jiangsu Province, China, Early Permian ( Chen & Bao 1986); Zhejiang Province, China, latest Permian ( Shi & Chen 1987); Guangxi, China, Late Permian ( Shi & Chen 2002); Gifu Prefecture, Japan, Early Permian ( Tanaka et al. 2012); Gifu Prefecture, Japan, Middle Permian ( Tanaka et al. 2013); Chaotian section, Sichuan Province, China, basal Wuchiapingian, Late Permian (this study; sample: 11CHAO88, see Table 1).

REMARKS

Ceratobairdia ? ambigua Ishizaki, 1964 shows a strong dorsal and ventral overlap. L of DB is about the third of carapace L. DB and VB are nearly straight at RV and slightly convex to nearly straight at LV. The maximum thickness is located at mid-L, slightly below midventral part of valves. In anterior and posterior views, VB is quite flat and bounded by a ventral ridge or alae. This structure, added to the flat ventral area, leads to a specific subtriangular shape that could be observed in anterior/posterior view. A sinuous midventral contact margin is also observed.We suggest then that Bairdia guangxiensis Guan, 1978 , Bairdia fujisan Tanaka & Maeda, 2012 and Bairdia nishiwakii Tanaka & Nishimura, 2013 are junior synonyms of C.? ambigua Ishizaki, 1964.

Suborder SIGILLIOCOPINA Martens, 1992 Superfamily SIGILLOIDEA Mandelstam, 1960 Family MICROCHEILINELLIDAE Gramm, 1975

Genus Microcheilinella Geis, 1933

TYPE SPECIES. — Microcheilusdistortus Geis,1932 byoriginaldesignation.

Microcheilinella wujiapingensis Zazzali , n. sp. ( Fig. 11G, H )

TYPE MATERIAL. — Holotype: one complete carapace (P6M3690; Fig. 11G ); paratype: one complete carapace (P6M3691; Fig. 11H ).

ETYMOLOGY. — From the Type horizon, Wujiaping Formation.

MATERIAL EXAMINED. — Four complete carapaces and three broken carapaces.

DIMENSIONS. — LV: L= 524-567 µm; H= 353-386 µm. Holotype: L= 535 µm; H= 370 µm. Paratype: L= 531 µm; H= 386 µm.

TYPE HORIZON. — Sample 11 CHAO 88, Wujiaping Formation, basal Wuchiapingian, Late Permian.

TYPE LOCALITY. — Chaotian section (30°23.713N, 106°49.615E), Sichuan Province, P. R. China.

OCCURRENCES. — Chaotian section, Sichuan Province, China, Wujiaping Formation, basal Wuchiapingian, Late Permian (sample: 11 CHAO 88, see Table 1).

DIAGNOSIS. — A species of Microcheilinella with medium sized carapace. Both valves present prominent mid-dorsal shoulder. Maximum W located behind mid-L at RV and in front of mid-L at LV.

DESCRIPTION

LV overlaps RV all around the carapace: very slightly at DB, narrowly at PDB, PVB and AVB, distinctly at ADB, AB, PB and VB. Overlap maximum at VB.

Hinge line straight, equalling about two third of RV length and about half the LV length, located well below DB of both valves which present prominent mid-dorsal shoulder.

RV: DB nearly straight and mid-dorsal shoulder broadly convex in lateral view. PDB and PB slightly flattened laterally. PB with small radius of curvature. PB maximum convexity located at mid-H. Ventral margin broadly convex. AB broadly rounded with maximum convexity at mid-H. Greatest L located at mid-H. Greatest H located slightly anterior to mid-L.

LV: DB nearly straight. Mid-dorsal shoulder more prominent than at RV. Anterior part of the shoulder nearly straight. ADB and AB broadly rounded with maximum convexity located slightly below mid-H. Posterior part of the shoulder slightly concave at median part. PDB nearly straight. PB with small radius of curvature, smaller than RV one. PB maximum convexity located slightly above mid-H. Ventral margin more convex at LV than at RV. Greatest L located slightly above mid-H at LV. Greatest H located slightly anterior to mid-L.

Carapace asymmetric in dorsal view with W max located behind mid-L at RV and posterior to mid-L at LV. RV thicker than LV.

REMARKS

Microcheilinella wujiapingensis Zazzali , n. sp. is close to M. venusta Chen, 1958 from the Early Permian of South China ( Chen 1958). It differs here by its DB which is nearly straight unlike the convex one of M. venusta Chen, 1958 , and by its mid-dorsal shoulder present on both valves. VB, at RV, is here broadly convex but seems nearly straight for M. venusta . VB, at LV, is here more convex than M. venusta one. Microcheilinella venusta maximum W is located near mid-L at both valves, whereas M. wujiapingensis Zazzali , n. sp. maximum W is located behind mid-L at RV and posterior to mid-L at LV. RV thicker than LV.

Microcheilinella wujiapingensis Zazzali , n. sp. is close to M. venusta Chen, 1958 (sensu Chen & Shi 1982. In this paper, the species is different from the original one) from latest Permian of South China, by its LV and RV general outline in lateral view, its mid-dorsal shoulder on each valves, the LV ends radius of curvature and maximum on convexity position and the general overlap. It differs by the maximum W, located in the anterior quarter of both valves for M. venusta (sensu Chen & Shi 1982) in dorsal view.

Microcheilinella pagodaensis Zazzali , n. sp. ( Figs 11I, J ; 19 )

TYPE MATERIAL. — Holotype: one complete carapace (P6M3692; Fig. 11I ); paratype: one complete carapace (P6M3693; Fig. 11J ).

ETYMOLOGY. — Reference to the pagoda at the top of the Chaotian section.

MATERIAL EXAMINED. — 22 complete carapaces and four broken carapaces.

DIMENSIONS. — L= 209-350 µm; H= 110-187 µm. Holotype: L= 263 µm; H= 138 µm. Paratype: L= 306 µm; H= 169 µm ( Fig. 19 ).

TYPE HORIZON. — Sample 11 CHAO 99, Wujiaping Formation, basal Wuchiapingian, Late Permian.

TYPE LOCALITY. — Chaotian section (30°23.713N- 106°49.615E), Sichuan Province, P. R. China.

OCCURRENCES. — Chaotian section, Sichuan Province, China, Maokou and Wujiaping Formations, Middle Capitanian-basal Wuchiapingian, Middle-Late Permian (samples: 11 CHAO 173, 11 CHAO 172, 11 CHAO 171,11 CHAO 166,11 CHAO 84,11 CHAO 90,11 CHAO 92, 11 CHAO 97, 11 CHAO 99, 11 CHAO 100, see Table 1).

DIAGNOSIS. — A species of Microcheilinella with small sized carapace. RV anterior half significantly higher than posterior one in lateral view. Maximum W located behind mid-L at RV and in front of mid-L at LV.

DESCRIPTION

LV overlaps RV all around the carapace: very slightly at AVB and VB, narrowly at AB, ADB, PDB and PB, distinctly at DB.

Hinge line straight, equalling about half L.

In right lateral view: DB slightly arched to nearly straight at RV and broadly convex at LV. PDB arched. PB with small radius of curvature. PB maximum convexity located below mid-H. PVB convex. VB slightly concave to nearly straight. AVB broadly convex. AB broadly rounded with maximum convexity located at mid-H. Greatest L located near mid- H. Greatest H anterior to mid-L at RV and near mid-L at LV. RV anterior half significantly higher than posterior one.

In dorsal view: posterior extremities rounded, anterior extremities slender. Maximum W located behind mid-L at RV and in front of mid-L at LV.

REMARKS

The new species is quite different from all the previously described species. The closest species is an unpublished species, M. sp. 10 ( Chitnarin 2010, unpublished PhD thesis; pl. 16, fig. 7), from the Middle Permian of Thailand. This last species has the same general outline. Here PB radius of curvature at RV is smaller, the overlap less marked at PDB and ADB and the RV anterior half significantly higher than posterior one.

Microcheilinella rectodorsata? Forel, 2010 ( Fig. 11K, L )

Microcheilinella rectodorsata Forel in Crasquin et al., 2010: 359, fig. 22A-G.

MATERIAL EXAMINED. — Six complete carapaces and two broken carapaces.

DIMENSIONS. — L= 292-416 µm; H= 163-235 µm.

OCCURRENCES. — Meishan section, Changxing Formation, Meishan Member, Changhsingian, Late Permian ( Crasquin et al. 2010);?Chaotian section, Sichuan Province, China, Wujiaping Formation, basal Wuchiapingian, Late Permian (this study, samples: 11CHAO80, 11CHAO81, 11CHAO85, 11CHAO95, 11CHAO99, 11CHAO100, see Table 1).

REMARKS

Our specimens are very similar to M. rectodorsata Forel, 2010 from the Late Permian of China ( Crasquin et al. 2010) but differ in having longer carapace, less marked overlapping and more acute PB.

Order PALAEOCOPIDA Henningsmoen, 1953 Suborder BEYRICHICOPINA Scott, 1961 Superfamily APARCHITOIDEA Jones, 1901 Family APARCHITIDAE Jones, 1901

Figures

FIG. 6. — Ostracods from Guadalupian-Lopingian boundary interval in South China: A-C, Ceratobairdia? ambigua Ishizaki, 1964; A, P6M3610, 11CHAO88; B, P6M3611, 11CHAO88; C, P6M3612, 11CHAO88; D, E, Bairdia chaotianensis Zazzali, n. sp.; D, holotype, P6M3613, 11CHAO172; E, paratype, P6M3614, 11CHAO88;F, Bairdia sp.1, P6M3615, sample 11CHAO173;G, Bairdia sp.2,P6M3616, sample 11CHAO173;H, I, Bairdia sp.3;H, P6M3617,sample 11CHAO171; I, P6M3618, sample 11CHAO171; J, Bairdia sp. 4, P6M3619, sample 11CHAO172; K, Bairdia sp. 5, P6M3620, sample 11CHAO171; L, Bairdia sp. 6, P6M3621, sample 11CHAO171;M, Bairdia sp. 7, P6M3622, sample 11CHAO171;N, O, Bairdia sp.8; N, P6M3623, sample 11CHAO170; O, P6M3624,sample 11CHAO165. All photographs represent complete carapaces in right lateral view, except F in left lateral view. Scale bar: 100 μm.

FIG. 11. — Ostracods from Guadalupian-Lopingian boundary interval in South China:A, Bairdiacypris? sp.12, P6M3684,sample 11CHAO95;B, Fabalicypris sp. 1, P6M3685, sample 11CHAO172; C, Fabalicypris sp. 2, P6M3686, sample 11CHAO82; D, Fabalicypris sp. 3, P6M3687, sample 11CHAO83; E, Fabalicypris sp. 4, P6M3688, sample 11CHAO95; F, Fabalicypris sp. 5, P6M3689, sample 11CHAO95; G, H, Microcheilinella wujiapingensis Zazzali, n. sp.; G, holotype, P6M3690, 11CHAO88; H, paratype, P6M3691, 11CHAO88; I, J, Microcheilinella pagodaensis Zazzali, n. sp.; I, holotype, P6M3692, 11CHAO99; J, paratype, P6M3693, 11CHAO166; K, L, Microcheilinella rectodorsata? Forel, 2010; K, P6M3694, 11CHAO81; L, P6M3695, 11CHAO80; M, Microcheilinella sp. 1, P6M3696, sample 11CHAO172; N, Microcheilinella sp. 2, P6M3697, sample 11CHAO167; O, Microcheilinella? sp. 3, P6M3698, sample 11CHAO156. All photographs represent complete carapaces, except O which is a broken one, all in right lateral view. Scale bar: 100 μm.

FIG. 19.— Height-length diagram of Microcheilinella pagodaensis Zazzali,n. sp.