Punctospirella fragilis ( Schlotheim, 1814 )

Sun, Zuoyu, Hao, Weicheng, Sun, Yuanlin & Jiang, Dayong, 2009, Silicified Anisian (Middle Triassic) spiriferinid brachiopods from Guizhou, South China, Acta Palaeontologica Polonica 54 (1), pp. 61-68 : 65-66

publication ID	https://doi.org/ 10.4202/app.2009.0107
persistent identifier	https://treatment.plazi.org/id/03E42D4F-DA70-FE04-FCF3-FA177291F83E
treatment provided by	Felipe
scientific name	Punctospirella fragilis ( Schlotheim, 1814 )
status

Treatment

Punctospirella fragilis ( Schlotheim, 1814)

Figs. 5 View Fig , 6A–D View Fig .

1814 Terebratulites fragilis sp. nov.; Schlotheim 1814: pl. 2: 4.

1972 Spiriferina fragilis ( Schlotheim, 1814) ; Siblík 1972: table 61, fig. 2.

1974 Punctospirella fragilis ( Schlotheim, 1814) ; Dagys 1974: 136–137, pl. 39: 2, 3; fig. 91.

1988 Punctospirella fragilis ( Schlotheim, 1814) ; Usnarska−Talerzak 1988: 688, pl. 2: 2.

1992 Punctospirella fragilis ( Schlotheim, 1814) ; Urošević et al. 1992: 473, pl. 1: 4–6.

1993 Punctospirella fragilis ( Schlotheim, 1814) ; Urlichs 1993: 211, fig. 2.

1997 Punctospirella fragilis ( Schlotheim, 1814) ; Torti and Angiolini 1997: 165, pl. 1: 25–27.

1997 Punctospirella fragilis ( Schlotheim, 1814) ; Kaim 1997: fig. 19B.

2003 Punctospirella fragilis ( Schlotheim, 1814) ; Pálfy 2003: 145, pl. Br−1: 13, 14.

Material.—12 shells, 6 ventral and 8 dorsal valves.

Dimensions.—L = 10.0 mm; W = 15.0 mm; H = 6.8 mm (GMPKU−P−6164, Fig. 6A View Fig 1 –A View Fig 5 View Fig ).

Description.—Shell medium−sized, transversely semicircular in outline, with a width−to−length ratio of about 1.45 ( Fig. 5 View Fig ), ventribiconvex. Hinge line straight, corresponding to the greatest width of shell or slightly shorter. Cardinal extremities subangular to nearly rounded. Anterior margin subrounded. Costae strong, rounded, 4–6 on each flank ( Fig. 6A View Fig 1 View Fig , A 2 View Fig , B 1, C 1, D 1 View Fig ).

Ventral valve convex. Interarea moderately high and concave ( Fig. 6A View Fig 3 View Fig , A 5 View Fig ). Beak pointed, incurved. Delthyrium open. Sulcus poorly developed, only slightly wider than interspaces between bordering costae. Dorsal valve weakly convex. Fold nearly as wide as bordering costae.

Ventral interior with strongly reduced to absent dental plates. Dental flanges incurved, nearly 1 mm high, joining the median septum near the apex ( Fig. 6D View Fig 2 View Fig ). Median septum high, extending one−third of the valve length.

Dorsal interior with knoblike, weakly striated, and probably bifurcating ctenophoridium ( Fig. 6B View Fig 2 View Fig , B 3 View Fig , C 2 View Fig , C 3 View Fig ). Cardinalia massive with cone−shaped sockets and well−developed and strongly incurved inner socket ridges ( Fig. 6B View Fig 3, C 3 View Fig ). Septalium and inner hinge plates absent.

Remarks.—Diagnostic characters of Punctospirella fragilis are the transverse outline, the wide median sulcus and fold, the presence of 10–12 costae (generally 10 on the ventral valve and 11 on the dorsal valve), and the high ventral median septum (see also Urošević et al. 1992; Torti and Angiolini 1997). Our specimens share these characters, except for the less developed sulcus and fold. As pointed out by Pálfy (2003), specimens from the Muschelkalk faunas of the Germanic Basin yield less prominent median rib (= dorsal fold) and corresponding interspace (= ventral sulcus), which correspond well with our material. Punctospirella fragilis is widely distributed both in the Alpine and Germanic Anisian deposits. In South China, Spiriferina (= Punctospirella ) fragilis ( Schlotheim, 1814) was first reported by Hsu and Chen (1943) from the Qingyan Formation (correlated with the Guanling Formation), central Guizhou Province, but with neither description nor illustration.

Stratigraphic and geographic distribution.—Middle Triassic of the Western Tethys and South China.

Kingdom	Animalia
Phylum	Brachiopoda
Class	Rhynchonellata
Order	Spiriferinida
Family	Pennospiriferinidae
Genus	Punctospirella