Hidden diversity within the Nemastoma bidentatum Roewer, 1914 complex (Opiliones: Nemastomatidae) Part I: Morphological evidence

Tone Novak,Ljuba Slana Novak,Günther Raspotnig,Jan Podlesnik,Miriam Gudrun Schaider,Igor Paušič,Peter Kozel,Saška Lipovšek,Christian Komposch

doi:10.5852/ejt.2021.777.1561

Tone Novak, Ljuba Slana Novak + Show 7 more

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https://doi.org/10.5852/ejt.2021.777.1561

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Abstract

Nemastoma bidentatum Roewer, 1914 is a complex of closely related litter-dwelling harvestmen, characterized by a penis glans with two pairs of lateral lancet-like spines, and a femur IV with a saw-like series of pointed tubercles. Here we a) revise the hitherto known taxa within the N. bidentatum complex, and b) analyze in detail the relations among the taxa in Slovenia. The study revealed that the N. bidentatum complex consists of four species: N. bidentatum Roewer, 1914 s. str., N. relictum Gruber & Martens, 1968 stat. nov., N. pluridentatum (Hadži, 1973) stat. nov. and N. kozari Novak, Kozel, Podlesnik & Raspotnig sp. nov. Moreover, N. bidentatum s. str. consists of six subspecies: N. bidentatum bidentatum Roewer, 1914, N. bidentatum sparsum Gruber & Martens, 1968, N. bidentatum gruberi Novak, Slana Novak, Kozel & Raspotnig ssp. nov., N. bidentatum martensi Novak, Slana Novak & Raspotnig ssp. nov., N. bidentatum schmidti Novak, Raspotnig & Slana Novak ssp. nov. and N. bidentatum sneznikensis Novak, Komposch, Slana Novak & Raspotnig ssp. nov. In Slovenia, the six subspecies of N. bidentatum form a parapatric complex around N. bidentatum schmidti. Hybrids occur in the contact zones between adjacent subspecies, but they are missing between distant subspecies. The taxonomic distinction of lineages / subspecies is congruent with their distribution patterns. With six of the nine taxa present, Slovenia is considered the center of the N. bidentatum complex speciation. At the time being, this complex is the most diversified harvestman group on a subspecific and young-species level and provides important details on speciation processes in Opiliones.

Highlights

In recent decades, relations among the higher taxa of harvestmen have become increasingly clear and amenable (Schönhofer 2013; Giribet & Sharma 2015; Fernández et al 2017)
The study revealed that the N. bidentatum complex consists of four species: N. bidentatum Roewer, 1914 s. str., N. relictum Gruber & Martens, 1968 stat. nov., N. pluridentatum (Hadži, 1973) stat. nov. and N. kozari Novak, Kozel, Podlesnik & Raspotnig sp. nov
The identification key includes both sexes in the nine pure taxa known to date, except the unknown female of N. pluridentatum stat. nov., and typical male hybrids

Summary

Introduction

Relations among the higher taxa of harvestmen have become increasingly clear and amenable (Schönhofer 2013; Giribet & Sharma 2015; Fernández et al 2017). One unresolved puzzle within Dyspnoi is the Nemastoma bidentatum Roewer, 1914 complex, Nemastomatidae Simon, 1872, distributed in Central and Eastern Europe, with sparse, disjunct localities in northern Europe These 1.8−2.5 mm long, black or nearly black Nemastoma (Fig. 1), have been recorded in Austria, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Germany, Hungary, Italy, Montenegro, Romania, Russia, Serbia, Slovakia, Slovenia and Turkey (Roewer 1914, 1923, 1951; Gruber & Martens 1968; Hadži 1973a; Staręga 1976; Martens 1978, 2006; Mučalica 1988; Ćurčić et al 1999; Klimeš 2000; Novak & Gruber 2000; Blick & Komposch 2004; Komposch & Gruber 2004; Novak 2004a, 2004b; Babalean 2005; Novak et al 2006; Schönhofer & Holle 2007; Komposch 2009, 2011; Schönhofer 2013; Kurt 2014)

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