Metalycaeus nipponensis (Reinhardt, 1877)

Pall-Gergely, Barna, Sajan, Sheikh, Tripathy, Basudev, Meng, Kaibaryer, Asami, Takahiro & Ablett, Jonathan D., 2020, Genus-level revision of the Alycaeidae (Gastropoda, Cyclophoroidea), with an annotated species catalogue, ZooKeys 981, pp. 1-220 : 1

Metalycaeus nipponensis (Reinhardt, 1877) Fig. 31A

Alycaeus Nipponensis Reinhardt, 1877: 68.

Alycaeus nipponensis - Pilsbry 1900: 381.

Alycaeus melanopoma Pilsbry, 1900: 382.

Alycaeus (Chamalycaeus) nipponensis - Kobelt 1902: 360.

Alycaeus (Metalycaeus) melanopoma - Kobelt 1902: 378.

Chamalycaeus (Chamalycaeus) nipponensis - Zilch 1957: 144, pl. 5, fig. 16.

Chamalycaeus nipponensis - Azuma 1982: 11, pl. 4, fig. 35; Minato 1988: 13.

Chamalycaeus (Metalycaeus) nipponensis - Egorov 2013: 37, figs 67a, b.

Metalycaeus nipponensis - Páll-Gergely et al. 2017: 73, figs 46A-C; Páll-Gergely and Asami 2017: 4.

Type locality.

“Kioto”.

Material examined.

Hakone Mts, Japan, leg. Schmacker, ANSP 78815 (lectotype of A. melanopoma , designated by Baker 1964, photographs examined); Japan, Yedo, Doenitz l., coll. Reinhardt, SMF 185407 (labelled as ‘typus’); 東京都 (Tōkyō-to), 多摩市 (Tama-shi), 蓮光寺聖跡記念館 境内 (Renkō-ji Seiseki Kinenkan keidai) [Tama City, Tokyo Metropolitan Prefecture], NSMT-Mo 79102 (91 shells).

Remarks.

Protoconch elevated, its last 0.5 whorl with spiral lines; ribbing on R2 is quite variable; there are 14-22, usually elevated and distinct ribs. In some specimens the ribs are relatively irregular, and they seemingly join to each other near the tube. This is, however, rather due to the fact that the shells are weathered (despite the fact that they were collected alive), because the elevated ribs are destroyed and appear lower. R1 with clearly visible, fine spiral striation.

In the examined sample, 91 specimens had an operculum, and of those 53 of them had the outer black circle present. In case of 27 specimens the outer circle was entirely missing, and in 11 cases only small fragments of the rings remained.

Figures

Figure 31. Type species of alycaeid genus-group taxa A Alycaeus melanopoma Pilsbry, 1900 (synonym of Chamalycaeus nipponensis (Reinhardt, 1877 )), lectotype (ANSP 78815; type species of Metalycaeus); B Metalycaeus magnificus (Godwin-Austen, 1914), syntype (NHMUK 1903.7.1.3115; type species of Raptomphalus). Photographs: downloaded from the website of ANSP (A), Harold Taylor (B).