Attenborougharion gen. nov. (Mollusca: Pulmonata: Helicarionidae): a likely case of convergent evolution in southeastern Tasmania

Abstract

Abstract. Helicarion Férussac, 1821 from southeastern Australia currently comprises five species of endemic semislugs. Analyses of comparative morphological data and partial sequences of the mitochondrial genes cytochrome c oxidase subunit I (COI) and 16S rRNA (16S) reveal that one of these species, Helicarion rubicundus Dartnall & Kershaw, 1978, which is restricted to southeastern Tasmania, is not closely related to the other known species of this genus. This species is distinguished from Helicarion in several key morphological characters, such as the bright two-toned red and green colouration of its larger body with a flattened tail that is keeled only at the tip, the triangular shape of the pneumostome, the degree and type of folding present in the spermoviduct and free oviduct, the presence of a longer, more slender bursa copulatrix, the presence of a small epiphallic caecum and a hooked flagellum, and the presence of irregular longitudinal pilasters in the penial interior in contrast to the v-shaped rows of papillose lamellae seen in Helicarion. Moreover, the mitochondrial phylogeny provides evidence that this species is phylogenetically distinct from Helicarion as well as any other currently described genus from southeastern Australia. Based on these findings, we here describe a new genus, Attenborougharion, for this species.

Feeling sluggish: The extreme semislugs of Australia (Stylommatophora,Helicarionidae)

“…The final concatenated sequence data set contained sequences of 35 specimens of Parmacochlea , Antiquarion , Fenestrarion , and the undescribed candidate species Helicarionidae WT 14 to WT 23 (Table 1) as well as 20 outgroup representatives that were used to root the trees. The outgroup representatives were selected based on a molecular phylogeny of Australian Helicarionidae (Hyman et al, 2007) and an ongoing revision of the Australian Helicarionidae (Hyman & Köhler, 2017, 2018a, 2018b, 2019a, 2019b; Hyman et al, 2017). In particular, we included all available sequences of helicarionid semislugs with extremely reduced shells.…”

“…Major radiations in the Australian Helicarionidae have previously been identified by a combination of key genital characters relating to the vagina, the epiphallic cecum, the penial retractor muscle, the epiphallic flagellum, and the spermatophore (Hyman & Köhler, 2017, 2018a, 2018b, 2019a, 2019b; Hyman et al, 2017). The four lineages identified here are no exception, although some additional characters separated them as well.…”

“…In the present study, we revise and describe all of the extreme semislug taxa from northern Queensland held in the collections of the AM and QM, and explore their evolutionary relationships with other helicarionid taxa, using comparative anatomy and phylogenetic analyses of the mitochondrial genes cytochrome c oxidase subunit I ( COI ) and 16S rRNA ( 16S ). This study forms part of a comprehensive revision of all eastern Australian helicarionids (Hyman & Köhler, 2017, 2018a, 2018b, 2019a, 2019b; Hyman et al, 2017).…”

Systematic revision of the microcystid land snails endemic to Norfolk Island (Gastropoda: Stylommatophora) based on comparative morpho-anatomy and mitochondrial phylogenetics

“…We have incorporated unpublished discriminant function analyses of shell shape carried out by Hyman (2005). Where additional shells were available and further clarification was required, additional analyses of shell shape were carried out using single factor ANOVA.…”

“…Three subfamilies are currently recognised within the Microcystidae: Microcystinae, recorded from the Cook and Austral Islands, Samoa, Tonga, the Philippines, Indonesia, Timor, China, Christmas Island and Madagascar; Liardetiinae, found throughout the Pacific and in South-East Asia; and Philonesiinae, found only in Hawaii (Baker 1941b). Microcystidae was treated as a subfamily of Helicarionidae by Baker (1938Baker ( , 1940Baker ( , 1941a but has been elevated to the rank of family by Hyman (2005). This proposal was followed by some (e.g.…”