Molecular and morphological divergence in a stygobiont gastropod lineage (Truncatelloidea, Moitessieriidae,Paladilhiopsis) within an isolated karstic area in the Mecsek Mountains (Hungary)

Abstract

Truncatelloid gastropods are one of the most species‐rich subterranean invertebrate groups. Their current taxonomy is based on morphological characters. However, this is not a comprehensive approach and does not take into account the degree of phylogenetic divergence between stygobiont populations inhabiting hydrologically isolated but geographically close caves. We studied two Paladilhiopsis populations of a small and isolated karstic area (Mecsek Mountains, Hungary) with two hydrologically separated cave systems, investigating morphological (shell morphometrics) and genetic (COI, 16S) divergence together. The populations differed both morphologically and genetically: we found strong divergence in the relative width of the shell (best described by the variable “shell angle”) and a 6.4% divergence in COI. This provides strong support for the presence of two distinct taxa; however, it is still doubtful whether they differ at the species or the subspecies level. In one of the caves, we found representatives of both haplotypes (and phenotypes), which can be explained by secondary contact after an allopatric divergence.

New Subterranean Freshwater Gastropod Species From Montenegro (Mollusca, Gastropoda, Moitessieriidae, and Hydrobiidae)

“…Thus, the Balkan stygobiont species had very favorable and longer, stable time of isolation with minimum migration routes available for the species radiation compared to their relatives from the Central Europe (tributaries of Rein, Main and Danube). As the two geographically very close but genetically different Paladilhiopsis species occurring in the Mecsek Mountains in south Hungary (Angyal et al 2018) suggests, areas such as the Mecsek or Dinarides, located further south of the main glaciation influence, could foster a more genetic diversity compared to the areas N of Alps and Carpathian.…”

Aquatic Organisms Research with DNA Barcodes

“…Moreover, in an important oligotrophic lake hosting the largest stromatolites in the world [110], the number of possible species increased from about 20 to more than 80, with a projection near to 120 [45]. The closeness (about 100 m) of this lake to a nearby deep sinkhole (64 m) shows almost an entirely different zooplanktonic fauna, explained by a different chemistry of the water [111][112][113].…”

Two new stygobiont freshwater snail species from Hungary (Mollusca: Gastropoda: Truncatelloidea)

“…Based on conchological characters, the latter was considered a junior synonym of the former by Pintér (1968a). However, both morphometric and molecular genetic differences were found in a recent paper (Angyal et al 2018), suggesting that they might be distinct species or subspecies. Both are treated as species and are currently classified in Paladilhiopsis Pavlović, 1913(MolluscaBase 2021.…”