On the origin and diversification of the stygobiotic freshwater snail genus Hauffenia (Caenogastropoda: Hydrobiidae) with special focus on the northern species and the description of two new species

Martin Haase,Jozef Grego,Roland Farkas,Zoltán Fehér,Zoltán Péter Erőss

doi:10.5852/ejt.2021.775.1555

Martin Haase, Jozef Grego + Show 3 more

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https://doi.org/10.5852/ejt.2021.775.1555

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Abstract

During systematic surveys of groundwater snails in Slovakia, Hungary and Bosnia and Hercegovina two new species of the genus Hauffenia, H. lozekiana sp. nov. from a single locality in Slovakia, and H. steffeki sp. nov. with a small range in Bosnia and Hercegovina were discovered and are here described based on shell morphology, anatomy and DNA sequence data (COI, 16S rRNA, ITS2). The discovery of H. steffeki sp. nov. extends the range of the genus considerably towards the south. Hauffenia lozekiana sp. nov. appears to be a relict surviving within the range of the today widely distributed H. kissdalmae. Based on a time tree, we developed a scenario for the origin and diversification of the genus. The ancestor probably evolved in the Miocene on the Balkans and with the gradual desiccation of the Paratethys and its remnant water bodies diversified towards the north. Karstic and in particular alluvial connectivities together with changing courses of paleo-rivers probably played an important role for dispersal. Ecological observations suggest that the phreatic rhizosphere, the delicate net of tree rootlets and their exudates, are important for the existence of these groundwater snails.

Highlights

Hydrobioid gastropods are notorious for their extreme diversity on the one hand and the difficulties they pose for identification and inference of relationships due to their small size, simple shell morphology, and high degree of convergence on the other hand (e.g., Hershler & Ponder 1998; Wilke et al 2000; Clark et al 2003; Delicado et al 2019)
H. kissdalmae was sister species to all other species, which formed a caterpillar in the order H. lozekiana sp. nov., H. kerschneri (Zimmermann, 1930), H. wienerwaldensis, and H. steffeki sp. nov. (Fig. 7)
The phylogenetic analyses based on different DNA markers and their combinations did not converge to an unambiguous topology, node support remained insignificant for many splits

Summary

Introduction

Hydrobioid gastropods (sensu Davis 1979) are notorious for their extreme diversity on the one hand and the difficulties they pose for identification and inference of relationships due to their small size, simple shell morphology, and high degree of convergence on the other hand (e.g., Hershler & Ponder 1998; Wilke et al 2000; Clark et al 2003; Delicado et al 2019). Many valvatiform species of the family Hydrobiidae Stimpson, 1865 characterized by a more or less depressed shell and open umbilicus are illustrative examples for species having been taxonomically misplaced due to their superficial similarities. One of these genera that has kept changing its specific composition, range, is Hauffenia Pollonera, 1898 (see Bodon et al 2001 and Rysiewska et al 2017 for partial overviews of taxonomic changes). In Hungary, Majoros and Krolopp have found valvatiform hydrobiid shells in the Aggtelek Karst region in the 1990s (Gábor Majoros pers. com.), but the first published record is only from 2008, when Hauffenia kissdalmae Erőss & Petró, 2008 was described (Erőss & Petró 2008)

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