Anatomy and taxonomic position of Elma H. Adams, 1866: a high-spired Southeast-Asian genus of Streptaxidae (Gastropoda: Eupulmonata)

Abstract

This paper describes the reproductive anatomy and the radula morphology of a Taiwanese species of Elma H. Adams, 1886, providing the first information on the anatomy of the genus. The species is provisionally identified as the type species of Elma, E. cf. swinhoei (H. Adams, 1866). Based on this and contrary to previous systematics, we suggest that Elma belongs to the subfamily Streptaxinae or Gibbinae, based on the presence of a well-developed penial sheath and the vas deferens which forms a loop under the penial sheath. Elma is the first high-spired, Southeast-Asian genus to be thus classified. We discuss possible relationships with other Streptaxoidea including the Elma-like genus Pseudelma Kobelt, 1904 and the highspired "Ennea" aliena Bavay et Dautzenberg, 1912.

Nagyelma n. gen. for Ennea aliena Bavay and Dautzenberg, 1912 (Gastropoda: Eupulmonata: Streptaxidae)

“…Differential diagnosis: Nagyelma n. gen. is probably most closely related to Elma (Fig. 1A-C; see Varga, 2012 andPáll-Gergely et al, 2015), which is similar in shell size and sculpture. However, shells of Elma species are all pointed-ovoid, whereas Nagyelma n. gen. is clearly ovoid with a blunt (domed) apical part.…”

“…Remarks: In an earlier publication, we discussed the systematic position of Elma (Páll-Gergely et al, 2015), which has similar anatomical traits to that of Nagyelma n. gen. Based on the morphology of the reproductive anatomy, Elma can be classified either in the in the subfamily Streptaxinae or in Gibbinae sensu Schileyko (2000). The former group ranges through tropical Asia, Africa and South America.…”

“…The former group ranges through tropical Asia, Africa and South America. In contrast, the Gibbinae (at least the group probably containing Gibbus Montfort, 1810, see Rowson et al, 2010 andPáll-Gergely et al, 2015) are mostly distributed in the Seychelles and the Mascarene islands, while the extinct type genus Gibbus is known form Mauritius. An Indoartemon Forcart, 1946 species from Sri Lanka clustered together with the South American Streptartemon Kobelt, 1905, andStreptaxis Gray, 1837 in the phylogenetic tree of Rowson et al (2010).…”

“…Photos: M. Caballer (B-D), B. Páll-Gergely (E-G) the absence of anatomical information, we refrained from erecting a genus for E. aliena (Páll-Gergely et al, 2015). In the present paper we first describe the anatomy of Ennea aliena based on newly-collected material, and erect a new genus for that species based on the anatomical and conchological differences from Elma.…”

Checklist of the genus Perrottetia Kobelt, 1905 (Pulmonata: Streptaxidae) of Vietnam, with description of a new species

“…They are diverse in Africa and south-eastern Asia (van benthem Jutting 1954, Siriboon et al 2013. Eight streptaxid genera (Discartemon, Indoartemon, Perrottetia, Stemmatopsis, Haploptychius, Oophana, Elma, and Huttonella) with thirty eight species have been recorded from Vietnam to date (SchileyKo 2011, Do & Do 2015, Páll-gergely et al 2015.…”