Silenites sureeae Chitnarin, 2017

Chitnarin, Anisong, Crasquin, Sylvie, Forel, Marie-Béatrice & Tepnarong, Prachya, 2017, Ostracods (Crustacea) of the Early-Middle Permian (Cisarulian-Guadalupian) from Central Thailand (Indochina Block): Part II, Orders Podocopida, Platycopida and Myodocopida, Geodiversitas 39 (4), pp. 651-690 : 675

Silenites sureeae Chitnarin , n. sp.

( Figs 14 J-L; 19)

TYPE MATERIAL. — Holotype, one complete carapace (SUT-09- 2650, Fig.14K ); paratypes, two complete carapaces (SUT-09-2648, Fig. 14J and SUT-09-2661, Fig. 14L );

ETYMOLOGY. — In honour of Dr Suree Teerarungsikul, Department of Mineral Resources, Thailand.

MATERIAL EXAMINED. — One incomplete and 13 complete carapaces.

DIMENSIONS. — H = 0.42-0.58 mm, L = 0.60-0.90 mm, H/L = 0.62- 0.70, Holotype: H = 0.73 mm, L = 1.08 mm; Paratype ( Fig. 14J ): H = 0.42 mm, L = 0.60 mm; Paratype ( Fig. 14L ): H = 0.58 mm, L = 0.90 mm. ( Fig. 19).

TYPE HORIZON. — Sample 07LB05-D3, Ta Kli section, Tak Fa Formation, Nakhon Sawan Province, central Thailand, Early Permian.

TYPE LOCALITY. — Nong Phai section (16°01’06’’N, 100°58’59’’E), Pha Nok Khao Formation, Phetchabun Province, central Thailand.

OCCURRENCES. — Samples 08LO02-5 and 08LO02-10, Nam Maholan section, Nam Maholan Formation , Loei Province, northeast Thailand, Early Permian ; sample 07 PB04-5 , Nong Phai section, Pha Nok Khao Formation, Phetchabun Province, central Thailand, Early Permian ; samples 07LB05-D2 and 07LB05-D3, Ta Kli section, Tak Fa Formation , Nakhon Sawan Province, Early Permian ; sample 07 PB08-3 , Ban Nean Sawan II section, Tak Fa Formation , Phetchabun Province, central Thailand, Middle Permian ; samples 08LB01-3 and 08LB01-6, Khao Som Phot section, Tak Fa Formation , Lopburi Province, Middle Permian .

DIAGNOSIS. — Species of Silenites with rounded subtriangular carapace, highly arched dorsal outline, short and straight DB of RV, H max is located at mid L, AB and PB of the same size.

DESCRIPTION

Carapace subtriangular; dorsal outline highly arched; DB short, convex at LV, straight at RV which inclined at 15- 25° rearward; ADB long and slightly convex, AB with large radius of curvature, maximum convexity located at lower fourth of H; AVB short and convex; VB concave; PVB short and convex; PB round with large radius of curvature, maximum convexity located at lower fourth of H; maximum of curvature of AB and PB located at the same level; greatest H located at mid L; surface smooth; LV larger and overlapping RV at DB.

1.2

Petasobairdia campbelli Chitnarin , n. sp. 1 Petasobairdia levicornuta Chen, 2002

Petasobairdia campbelli Chitnarin , n. sp. 0.8

Holotype 0.6 0.4 Paratype

) 0.2 mm

(

H L (mm) 0

0.6 0.8 1 1.2 1.4 1.6 1.8

REMARKS

Silenites sureeae Chitnarin , n. sp. looks similar to three species from the Early Permian of Jiangsu Province, Eastern China ( Chen & Bao 1986): 1) Silenites testatus Chen, 1958 (in Chen & Bao 1986: 125, pl. 2, figs 10, 11) but differs in having more rounded DB and maximum H located at mid L; 2) S. cf. marginiferus (Geis, 1932) sensu Chen & Bao (1986: 125, 126, pl. 2, fig. 12) but can be differentiated by the straight DB on RV of S. sureeae ; and 3) S. unicostus Chen & Bao, 1986 ( Chen & Bao 1986: 126, pl. 2, figs 13, 14) but it lacks a crest on posteroventral region of RV.

Figures

FIG. 14. — Ostracods from the limestones of the Indochina Block, Central Thailand. All specimens are stored at the Suranaree University of Technology Collections (Nakhon Ratchasima, Thailand) numbers SUT-09-xxxx. All the specimens are complete carapaces in right laeral view. A, Bairdiacypris sp. A, SUT-09-2340, sample 07PB05-3. B, C, Bairdiacypris sp. B; B, SUT-09-2341, sample 08LB01-2; C, SUT-09-2351, sample 07LB04-4; D, Bairdia sp. I, SUT-09-2314, sample 07LB04-13; E, Bairdiacypris sp. C, SUT-09-2352, sample 07PB08-3; F, Fabalicypris sp. A, SUT-09-2525,sample 08PB01-2; G, Fabalicypris sp. B, SUT-09-2526, sample 08LB01-3; H, Bairdia sp. J, SUT-09-2315,sample 08LO07-10; I, Bairdiidae indet.sp. A, SUT-09-2492, sample 08LB01-6; J-L, Silenites sureeae Chitnarin, n. sp.; J, paratype,SUT-09-2648, sample 07PB04-5; K, holotype, SUT-09-2650, sample 07LB05-D3; L, SUT-09-2661,sample 08LO02-10; M, Silenites sp., SUT- 09-2647, sample 07PB05-5; N, O, Kempfina sp.; N, SUT-09-2534, sample 08LB01-2; O, SUT-09-2536, sample 08LO01-4. Scale bars: 100 μm.