54 | wileyonlinelibrary.com/journal/zsc Zoologica Scripta. 2018;47:54–62. © 2017 Royal Swedish Academy of Sciences Received: 22 March 2017 | Accepted: 5 September 2017 DOI: 10.1111/zsc.12259 ORIGINAL ARTICLE Phylogeny and reclassification of the Caucasigenini radiation from the Caucasus region (Gastropoda, Hygromiidae) Marco T. Neiber 1 | Frank Walther 1,2 | Bernhard Hausdorf 1 1 Zoological Museum, Center of Natural History, University of Hamburg, Hamburg, Germany 2 Universität Duisburg-Essen, Essen, Germany Correspondence Bernhard Hausdorf, Zoological Museum, Center of Natural History, University of Hamburg, Hamburg, Germany. Email: hausdorf@zoologie.uni-hamburg.de Funding information Volkswagen foundation, Grant/Award Number: Biogeography of the land molluscs of the Caucasus The Caucasigenini is an endemic radiation of hygromiid land snails from the Caucasus region. A phylogenetic analysis of morphological characters of the genita- lia and the shell showed that the morphological characters are insufficient for resolv- ing the relationships within the Caucasigenini. Convergences of the few parsimony informative characters in other groups of the Hygromiidae demonstrate that these characters are not reliable indicators of phylogenetic relationships. Phylogenetic analyses of sequences of cox1, 16S rDNA, 5.8S rDNA, ITS2 and 28S rDNA revealed several well-supported groups. The relationships among these groups could not be resolved. It is likely that these groups originated in a rapid radiation during the uplift of the Caucasus. Based on the molecular phylogeny, we propose a new classification of the species of the Caucasigenini and establish a new genus, Lazicana gen. n. KEYWORDS Caucasigenini, Caucasus, Hygromiidae, land snail, phylogeny 1 | INTRODUCTION The family Hygromiidae Tryon, 1866, as delimited by Razkin et al. (2015) and Neiber, Razkin, and Hausdorf (2017) is a highly diverse group of land snails including about 400 species with a distribution range stretching throughout the Palearctic region and reaching southwards to the north-eastern Ethiopian region (Neiber et al., 2017; Schileyko, 2006). So far, the clas- sification of the family largely rested on the number and the structure of the dart apparatus, an accessory genital organ (Nordsieck, 1987, 1993; Schileyko, 1978a,b, 1991, 2006). The dart apparatus is composed of glands, the so-called glandulae mucosae, the dart sac and often an accessory sac (Figure 1). The glandulae mucosae secrete mucus containing an allohor- mone. During courtship, the mucus is transferred with the cal- careous dart produced in the dart sac into the mating partner (Chase, 2007). The allohormone affects the female tract of the mating partner in such a manner that the spermatophore is transferred more slowly into the bursa copulatrix, where it is digested. Thus, more of the sperm can leave the spermato- phore before it is digested and can reach the sperm storing organ and fertilize eggs (Chase, 2007). The accessory sac may be involved in storing the secretion of the glandulae mucosae or squeezing it onto the dart or the mating partner. Molecular phylogenetic analyses revealed that the dart apparatus has been duplicated in different families of the Helicoidea in parallel and that in groups with a duplicated dart apparatus, one or even both dart apparatus have been lost several times convergently in different geographic regions (Neiber et al., 2017). Thus, several of the previously distin- guished subfamilies based on the number of dart apparatus proved to be polyphyletic. In contrast, several of the clades found in the molecular phylogenetic analyses represent re- gional radiations that partly show a high variation in the structure of the dart apparatus. Thus, a new classification of the Hygromiidae into three subfamilies, Hygromiinae Tryon, 1866, Leptaxinae Böttger, 1909, and Trochulinae Lindholm, 1927, has been proposed (Neiber et al., 2017). These sub- families represent deeply divergent clades, but cannot be defined by morphological characters because of rampant homoplasies. These subfamilies are further subdivided into usually regionally restricted radiations, which were classified as tribes. One of these regional radiations, the Caucasigenini Neiber, Razkin & Hausdorf, 2017, of the Trochulinae