Anomphalus, Meek & Worthen, 1866

Ketwetsuriya, Chatchalerm, Karapunar, Baran, Charoentitirat, Thasinee & Nützel, Al- Exander, 2020, Middle Permian (Roadian) gastropods from the Khao Khad Formation, Central Thailand: Implications for palaeogeography of the Indochina Terrane, Zootaxa 4766 (1), pp. 1-47 : 24

Anomphalus ? blancus Kues & Batten, 2001

( Fig. 17 F–L)

Anomphalus ? blancus Kues & Batten, 2001: 44, figs 8.23–8.28.

Material. Two specimens: ESKU-19- LP 67, 96.

Dimensions (mm): ESKU-19- LP 67: height = 2.5; width = 3.0; apical angle = 124º. ESKU-19- LP 96: height = 2.3; width = 2.6; apical angle = 125º.

Description. Shell small, low-spired but spire clearly elevated, last whorl much higher than spire, turbiniform to naticiform, consisting of two to four whorls; whorls smooth, rounded, convex; whorls embrace at or slightly below periphery at mid-whorl; suture shallow but distinct; aperture somewhat circular, columellar lip straight to gently arched joining outer lip; base convex, minutely phaneromphalous.

Remarks. These specimens are very similar to the illustrations of Anomphalus ? blancus Kues & Batten, 2001 (p. 44, fig. 8.23–8.28) from the Middle Pennsylvanian of New Mexico in shell shape and the whorl expansion rate. Kues & Batten (2001) assigned A.? blancus questionably to the genus Anomphalus due to its higher spired and more inflated shell which differs from typical species of Anomphalus in these respects that have low-spired or planispiral shells. The studied specimens also resemble the specimens assigned to Anomphalus sp. from the Permian of Malaysia by Batten (1979, p. 8, figs 10–11). However, the present specimens are more high-spired. Batten (1979) and Kues & Batten (2001) discussed that their specimens closely resemble the genus Turbinilopsis in shell shape and proportions of the shell, but Turbinilopsis is distinguished in having an obvious callus within the umbilicus. Other species of Turbinilopsis which have been reported from the Permian of Southeast Asia differ distinctly from the present material. T. rotundus Delpey, 1941 (p. 276, fig. 18) from Cambodia (see also Batten 1979) has a much more straight whorl face and a blunt apex. The specimens assigned to Turbinilopsis ? sp. by Mansuy (1914, pl. 4, fig. 11) have a lower spire and hence a greater apical angle. The present specimens are placed tentatively in the genus Anomphalus . They are rather high-spired for this genus and hence become similar to the genus Anematina which generally is even more high-spired.

Figures

FIGURE 17. A–E, Anomphalus cf. vanescens Yochelson, 1956, A–C, ESKU-19-LP 30. D–E, ESKU-19-LP 50. F–L, Anomphalus? blancus Kues & Batten, 2001, F–I, ESKU-19-LP 67. J–L, ESKU-19-LP 96. Scale bars represent: 2 mm (A–C); 1 mm (D–L).