Chamalycaeus Moellendorff , 1897

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

Genus Chamalycaeus Moellendorff, 1897

Alycaeus (Chamalycaeus) Möllendorff, 1897b: 93.

Chamalycaeus - Kobelt and Möllendorff 1897: 148; Páll-Gergely et al. 2017: 5-7.

Chamalycaeus (Chamalycaeus) - Thiele 1929: 107-108; Wenz 1938: 477-478; Egorov 2013: 35.

Type species.

Alycaeus (Chamalycaeus) fruhstorferi (Fig. 6B ) by monotypy, see also Remarks.

Diagnosis.

Shell very small to medium sized (D: 2-5 mm), usually flattened, discoid or low triangular, protoconch smooth (or very finely pitted), elevated even if the spire is low; R1 usually roughly reticulated due to spiral striation and radial ribs (sometimes prominent); R2 from short to very long, with widely spaced, sharp, elevated ribs; R3 normally developed. Operculum usually thin, without notable outer structures. Radula is known for a single species (central tooth with five cusps, broad, central cusp pointed).

Differential diagnosis.

See under Alycaeus and Table 3 . Metalycaeus species are identical, with the exception of the spirally striated protoconch.

Distribution.

Chamalycaeus is distributed from the southeastern Himalaya Region, the Malay Peninsula, Sumatra, Java, Borneo, Sulawesi, and the Philippine Palawan Island (Fig. 9 ).

Remarks.

Kobelt and Möllendorff (1897) listed the species of “Pneumonopoma”, which included all members of the genus Alycaeus . They introduced "Subgenus Chamalycaeus n." ( Kobelt and Möllendorff 1897: 148), indicating it as a new subgenus, and included 44 species within their new group. The subgenus Chamalycaeus , however, was previously mentioned in another paper in the same volume of the Nachrichtsblatt der Deutschen Malakozoologischen Gesellschaft, in which Möllendorff (1897b: 93) described Alycaeus (Chamalycaeus) fruhstorferi . Möllendorff’s (1897b) paper was published in July-August, whereas that of Kobelt and Möllendorff (1897) was published in September-October. Accordingly, the genus Chamalycaeus was described by Möllendorff (1897) and its type species is Alycaeus (Chamalycaeus) fruhstorferi by monotypy. On the other hand, Alycaeus (Chamalycaeus) fruhstorferi was not listed in Kobelt’s and Möllendorff’s (1897) paper, which indicates that they aimed to describe A. fruhstorferi after their revision of Alycaeus . Moreover, Kobelt’s (1902) monograph referred to Chamalycaeus as it was introduced by Kobelt and Möllendorff (1897). Almost all subsequent treatments erroneously attributed the name Chamalycaeus to Kobelt & Möllendorff, 1897 ( Kobelt 1902; Gude 1921; Yen 1939; Zilch 1957; Azuma 1980; Minato 1982b, 1987a, 2005; Minato and Yano 1988; Egorov 2005; Zhang et al. 2008) and referred to Alycaeus andamaniae Benson, 1861 as the type species as subsequent designated by Gude (1921). The ICZN Code 70.2 states the following: "If it is found that an earlier type species fixation has been overlooked, the overlooked fixation is to be accepted and any later fixations are invalid. If this is considered to cause instability or confusion the case is to be referred to the Commission for a ruling". Therefore, we must examine whether the correction of the type fixation would cause instability. In our view, confusion or instability would be caused only if the majority of authors who have described species within Chamalycaeus were unaware of the shell morphology of Alycaeus andamaniae (incorrectly selected as the type species for Chamalycaeus ). No detailed description of Alycaeus andamaniae has ever been published, and our revision suggests that most authors who described Chamalycaeus species did not examine samples of Alycaeus andamaniae . Thus, we find no reason to present this issue to the Commission. Instead, we follow Egorov (2013) in accepting Möllendorff (1897b) as the author of Chamalycaeus . Thus, in accordance with Art. 70.2 of the Code we clarify that Alycaeus (Chamalycaeus) fruhstorferi is the type species of Chamalycaeus Möllendorff, 1897 by monotypy.

Figures

Figure 6. Type species of alycaeid genus-group taxa A Alycaeus eydouxi Venmans, 1956 (SMF 109290; type species of Alycaeus) B Chamalycaeus fruhstorferi (Moellendorff, 1897), lectotype (SMF 109481; type species of Chamalycaeus). Photographs: Barna Pall-Gergely (A) and Frank Walther (B).

Figure 9. Distribution of Chamalycaeus Moellendorff, 1897 (dark shaded area) and Metalycaeus Pilsbry, 1900 (light shaded area).