Gastropods from the Permian of Guangxi and Yunnan Provinces, South China

Journal of Paleontology, Jan 2002 by Hua-Zhang, Pan, Erwin, Douglas H

Genus RETISPIRA Knight, 1945

Type species.-Retispira bellireticulata Knight, 1945.

Chinese Permian species.-Retispira matanensis Pan Y T. and Yu, 1993, from the Second Member of the Upper Permian, Heshan Formation, Hesham County, Guangxi Province; Retispira multicancellata Yu, in Wang and Xi, 1980, and Retispira strictura Yu, in Wang and Xi, 1980, from the Upper Member of the Xuanwei Formation, Panxian County, Guizhou Province; Retispira strictocanalicula Wang and Xi, 1980, from Loping Series, Liuzhi County, Guizhou Province.

RETISPIRA MATANENSIS Pan Y I and Yu, 1993 Figure 3.14-3.18

Retispira matanensis PAN Y I AND YU, 1993, p. 32, pl. 1, figs. 4, 5.

Description.-Small bellerophontiform shell; umbilici relatively large, and deep; umbilical margin fairly steep; selenizone moderately broad, slightly prominent above the shell, bordered by two coarse spiral threads; within the selenizone there is a spiral thread and indistinct lunulae; aperture reniform in outline, outer lip strongly reflected; surface ornament of three grades of spiral sculpture: coarse, moderate and fine spiral threads and two series of collabral threads, producing a fine and dense reticulate sculpture.

Occurrence.-Upper Member of the Heshan Formation, Matan section (M48), Heshan County, Guangxi Province.

Discussion.-The two specimens are conspecific with Retispira matanensis Pan Y. T and Yu (1993) from the Second Member of the Heshan Formation at Matan village, Heshan County, Guangxi Province. This species is similar to Retispira multicancellata Yu (in Wang and Xi, 1980) from the Upper Permian Lungtan Formation in Pan Xian, Guizhou Province but is distinguished from it by larger shell size, a narrower selenizone, and a wider aperture.

RETISPIRA SINENsis new species Figure 3.9-3.13

Diagnosis.-Subglobose bellerophontiform shell; a deep, open, U-shaped slit; selenizone narrow and indistinct; surface ornamented by 28 prominent spiral carina.

Description.-Medium-sized, bellerophontiform shell, whorl profile elliptical and broadly rounded on dorsum, becoming sharply rounded laterally, so that the lateral whorl surface is relatively steeply inclined; umbilici deep and not broad; an open and moderately broad U-shaped slit on dorsum; selenizone indistinct, narrow and depressed, bordered by two sharp, coarse ridges; anterior lip broadly rounded; lateral lip thin and not flared; columellar lips thin and slightly curved; parietal area covered by a thin inductura; surface ornamented by about 28 prominant spiral carina with the interspaces less than the width of each spiral carina on the parietal area, and more than the width of each carina on the dorsum, especially near the margin of aperture; the two widest interspaces lie on both sides of coarse spiral ridges adjacent to selenizone; collabral threads visible on umbilical area, indistinct collabral costae visible on dorsum near aperture.

Etymology.-This species is named in Chinese, sin, meaning Chinese Nation.

Types.-Holotype USNM 127592, locality M47.

Measurements (mm).-Maximum shell diameter: 16.5; maximum aperture width: 14.90; maximum aperture height: 8.00 (width of sinus: 1.2 mm, length of sinus: 4.5 mm).