Publication details
East Asian Parakaliella harimensis is in fact Euconulus of a remarkable genetic diversity
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| Year of publication | 2024 |
| Type | Conference abstract |
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| Description | Euconulus is one of the most widely distributed genera of land snails in the Holarctic. It is characterized by a simple shell morphology and minute size ranging from 2.3 to 3.5 mm in diameter. About ten nominal Euconulus species have been described from Holarctic, however, there are several unresolved taxonomical issues, among which is the existence of potentially species-level clades in the Euconulus fulvus group. Our previous molecular data identified such a distinct clade in Japan, which seemed to be a new species candidate. By including more samples from Japan and southeast Asia we aim to further explore taxonomic status of this clade using an integrative approach. Two nuclear (ITS1, ITS2) and two mitochondrial (COII, 16S) markers were used to reconstruct the phylogenetic relationships of the genus Euconulus using 51 samples of all five nominal species from the E. fulvus group. We tackle the aim also by morphometry analysis using classical shell measurements and geometric morphometry with 19 landmarks. Based on the phylogenetic tree reconstruction we documented six distinct groups. The group including the populations from east and southeast Asia was genetically highly divergent and significantly different in shell morphology from all the remaining species. This group resembled Parakaliella harimensis, and this similarity was confirmed by including a lectotype and paralectotype in geometric morphometry analysis. We, therefore, propose this species to bear the name Euconulus harimensis by changing the taxonomical status of P. harimensis. Its exceptional degree of genetic intraspecific variability can be explained by climatic stability in its range through the Pleistocene climatic cycles, contrary to the remaining Euconulus species, whose distributions were more dynamic in response to sharp climatic shifts during the Pleistocene. |