Overlooked but not forgotten: the first new extant species of Hawaiian land snail described in 60 years, Auriculella gagneorum sp. nov. (Achatinellidae, Auriculellinae)

Abstract

Recent surveys of Oahu’s Waianae Mountains uncovered a small, previously undescribed species of Auriculella that is conchologically similar to the three members of the A. perpusilla group all of which are endemic to the Koolau Mountain Range. However, sequence data demonstrate that the perpusilla group is not monophyletic. Moreover, the new species is not closely related to A. perpusilla or A. perversa, the only extant members of the group, but instead is sister to A. tenella, a species from the high spired A. castanea group. A neotype is designated for A. auricula, the type species of Auriculella; all members of the conchologically similar perpusilla group are anatomically redescribed; and lectotypes designated for A. minuta, A. perversa, and A. tenella. The new species is described and compared to the type of the genus, members of the perpusilla group, and the genetically similar species A. tenella.

Molecular phylogenetics and premating isolation in the punctoid land snails of Belau (Republic of Palau, Oceania)

“…Molecular phylogenetics is a useful foundation for such study, since it allows us to explore biogeography and the evolution of morphological features using a relatively independent set of characters. Pacific island land snail phylogenies from lesser‐studied island groups and taxa also contribute to our as‐yet incomplete picture of land snail diversification on islands, which for practical reasons has focused on larger‐bodied and better‐collected taxa such as achatinelline or partulid tree snails (Haponski et al., 2017; Holland & Hadfield, 2004; Lee et al., 2014; Thacker & Hadfield, 2000; Yeung et al., 2020) and/or well‐studied island archipelagos, such as the Hawaiian Islands (Rundell et al., 2004). Despite well over a 100 years of interest in the evolution of Pacific island land snail faunas (Gulick, 1873; Pilsbry, 1900), the phylogenetics of most Pacific island land snails remains to be explored.…”

Tiny Snails With Large Distributions: Systematics and Delimitation of the Pacific Land Snails Pacificella and Lamellidea (Stylommatophora: Achatinellidae: Pacificellinae)

“…The volcanic islands of Kaua'i, which formed 4.7 Ma, and the northwestern Hawaiian Islands, which formed between 7.3 and 29.8 million years ago (J. P. Price & Clague, 2002), are all older than O'ahu, but several other groups of Hawaiian land snails also reach their greatest diversity on O'ahu. These include the Achatinellinae (Cowie & Holland, 2008), Auriculella (Pilsbry & Cooke, 1912-1914Yeung et al, 2020), and the Amastridae (Hyatt & Pilsbry, 1910-1911Régnier et al, 2015), and together this suggests that the higher diversity on the island of O'ahu is a recurring pattern among land snails and unlikely to be an artifact of sampling effort. Of course, patterns of diversity in Hawaiian land snail taxa may differ due to the timing of colonization and dispersal events (Cowie, 1995).…”

“…Evolutionary relationships of the subfamily Achatinellinae have been investigated in several studies (Holland & Hadfield, 2004, 2007; M. R. Price et al, 2021;Thacker & Hadfield, 2000), and genomic diversity has been investigated in a few species following severe population bottlenecks (M. R. Price et al, 2015). Less is known about the systematics, ecology, biology, and conservation status of the smaller-shelled species in the subfamily Auriculellinae (Pilsbry & Cooke 1915[in 1914-1916; Cooke & Kondo, 1961;Yeung et al, 2020), and knowledge of microsnails (shell height < 5 mm, Liew et al, 2008) in the subfamilies Tornatellininae, Tornatellidinae, and Pacificellinae is poorer still (Pilsbry & Cooke 1915-1916[in 1914-1916; Cooke & Kondo, 1961).…”

Taxonomy, Conservation, and the Future of Native Aquatic Snails in the Hawaiian Islands

“…These included (1) surveys to identify where native snails persist; (2) identification of immediate threats to species and their populations; (3) protection and restoration of habitats; (4) updating taxonomic and distributional status of extant species. Since 2011, more than 1000 surveys have been conducted across the main Hawaiian Islands in search of Hawaii's native land snails, in which more than 200 species have been recorded or rediscovered, with several species new to science (e.g., [93][94][95]; approximately 75 species were estimated to persist prior to this endeavor. Similar efforts need to be supported for evaluation of freshwater snails in Hawaii, and the actions outlined by Solem [12] and amended by Yeung and Hayes [93] should be implemented immediately to thoroughly update the systematic and conservation status of this highly threatened freshwater fauna.…”