Integrative taxonomy of Gymnobela and Pontiothauma (Conoidea: Raphitomidae) from Australian waters provides more evidence of transoceanic distribution in deep-sea gastropods
Criscione, F.; Hallan, A. (2024). Integrative taxonomy of Gymnobela and Pontiothauma (Conoidea: Raphitomidae) from Australian waters provides more evidence of transoceanic distribution in deep-sea gastropods. J. Nat. Hist. 58(37-40): 1429-1459. https://dx.doi.org/10.1080/00222933.2024.2383786
In: Journal of Natural History. Taylor & Francis: London. ISSN 0022-2933; e-ISSN 1464-5262, meer
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| Trefwoorden |
Biodiversity
Deep sea
Gymnobela angulosa Sysoev, 1988 [WoRMS]; Gymnobela engonia A. E. Verrill, 1884 [WoRMS]; Pontiothauma transregna Criscione & Hallan, 2024 [WoRMS]; Radula Mörch, 1853 [WoRMS]
Marien/Kust |
| Author keywords |
Shell, mtDNA, species delimination |
| Abstract |
The deep-sea raphitomid genus Gymnobela Verrill, 1884 (Neogastropoda: Conoidea) has historically been a container for a multitude of raphitomid species, assigned to this genus almost exclusively based on shell characters. Consequently, the genus has become taxonomically inflated. However, a 2021 molecular study redefined Gymnobela and taxonomically revised the genus. Herein, we present an integrative taxonomic study that, mainly based on samples from Australian waters, further defines this problematic genus, as well as the closely related genus Pontiothauma E.A. Smith, 1895. An automatic barcode gap discovery (ABGD) analysis of three mitochondrial genes resulted in six primary species hypotheses (four in Gymnobela and two in Pontiothauma). We recognised morpho-anatomical and bathymetric/geographical characters distinct to all six and found available names for four; we name one new species, Pontiothauma transregna sp. n., but abstain from naming one presumably unnamed Pontiothauma due to a lack of well-preserved adult specimen material. We provide clear synapomorphic characters unique to both Gymnobela and Pontiothauma, notably those of the radula. Furthermore, we present the first evidence supported by molecular data of a transoceanic distribution among the raphitomids, namely in Gymnobela angulosa Sysoev, 1988. Additionally, we recognise non-molecular evidence that might indicate similarly wide distributions in Gymnobela agasizzi (Verrill and Smith, 1880), Gymnobela engonia Verrill, 1884 and Gymnobela frielei Verrill, 1885. Consequently, and to avoid taxonomic splitting, we herein advocate for wide-ranging investigation of worldwide material when conducting taxonomic studies on deep-sea conoideans, due to growing evidence of transoceanic distributions in the group. Finally, through an exhaustive search of worldwide repositories and the literature, and in conjunction with our molecular, morpho-anatomical and bathymetric/geographical data, we have reassigned 16 species from Gymnobela to other genera within the family Raphitomidae. |
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