Taxonomic revision and insights into the speciation mode of the spider Dysdera erythrina species-complex (Araneae : Dysderidae): sibling species with sympatric distributions

Abstract

The genus Dysdera Latreille, 1804, a species-rich group of spiders that includes specialised predators of woodlice, contains several complexes of morphologically similar sibling species. Here we investigate species limits in the D. erythrina (Walckenaer, 1802) complex by integrating phenotypic, cytogenetic and molecular data, and use this information to gain further knowledge on its origin and evolution. We describe 16 new species and redescribe four poorly known species belonging to this clade. The distribution of most of the species in the complex is limited to southern France and the north-eastern Iberian Peninsula. The species studied do not show any obvious differences in habitat preference, and some of them even occur sympatrically at certain sites. They probably feed on the same type of prey as they readily capture woodlice. On the other hand, they differ in body size, mouthparts shape, sculpturing of carapace, morphology of the copulatory organs, karyotype and DNA sequences. Experimental interspecific mating showed a partial precopulatory behavioural barrier between D. erythrina and D. cechica, sp. nov. Our data suggest that karyotype evolution of the complex included chromosome fusions and fissions as well as translocations (between autosomes as well as autosomes and sex chromosomes). We hypothesise that chromosome rearrangements generating reproductive incompatibility played a primary role in speciation within Dysdera complexes. Dysdera spiders are poor dispersers, and their original distribution areas (forested areas in the Mediterranean) were repeatedly fragmented during Quarternary climatic oscillations, facilitating integration of chromosome rearrangements into karyotypes by genetic drift. Sympatric occurrence of closely related species may have been promoted by prey segregation as suggested by differentiation in body size in co-occurring species. The following new species are described: D. catalonica, sp. nov., D. cechica, D. dolanskyi, sp. nov., D. fabrorum, sp. nov., D. garrafensis, sp. nov., D. graia, sp. nov., D. kropfi, sp. nov., D. minairo, sp. nov., D. portsensis, sp. nov., D. pradesensis, sp. nov., D. pyrenaica, sp. nov., D. quindecima, sp. nov., D. septima, sp. nov., D. stahlavskyi, sp. nov., D. tredecima, sp. nov. and D. undecima, sp. nov.

Insights into the karyotype and genome evolution of haplogyne spiders indicate a polyploid origin of lineage with holokinetic chromosomes

“…The karyotype of ancestral Dysderoidea featured an extremely low number of chromosome pairs, presumably three pairs, as suggested by the phylogenetic distribution of this pattern. It was found in the basal lineage of Dysderoidea, the family Segestriidae ( Ariadna ) 30 , this study , all primary clades of Dysderidae (Dysderinae, Rhodinae, Harpacteinae) 6,31 , this study , and in various evolutionary lineages of Oonopidae this study . Concerning the subfamily Dysderinae, however, three pairs are probably a derived pattern – it was only found in D .…”

“…The X0 system was also found in many other spider groups, where it arose by chromosome fusion of two or more X chromosomes 5,6 . In Segestria (Segestriidae) (2 n ♂ = 14) 29 and in Dysdera dolanskyi (Dysderidae) (2 n ♂ = 20) 31 the X 1 X 2 0 system was found, which is supposed to be ancestral in spiders 30 . However, it is probably a derived system in spiders with holokinetic chromosomes.…”

“…The three chromosome pairs of this species probably arose from a karyotype with four chromosome pairs, a supposedly ancestral feature of the Dysdera erythrina group, to which D . septima belongs 31 . The frequent occurrence of a karyotype with four chromosome pairs in the subfamily Dysderinae 7,27,28,31 , this study indicates that this pattern might be an ancestral character in this most derived clade within Dysderidae (Fig.…”

“…Concerning the subfamily Dysderinae, however, three pairs are probably a derived pattern – it was only found in D . septima 31 . The three chromosome pairs of this species probably arose from a karyotype with four chromosome pairs, a supposedly ancestral feature of the Dysdera erythrina group, to which D .…”

Morphological and cytogenetic characteristics of Neobisium (Blothrus) slovacum Gulička, 1977 (Pseudoscorpiones, Neobisiidae), the northernmost troglobitic species of the subgenus Blothrus in Europe

“…Harrison et al 2014) arachnid groups. However, cytogenetic techniques can also be useful for the identification of cryptic species within various orders of arachnids, such as harvestmen (Šťáhlavský et al 2018a), spiders (Řezáč et al 2018), scorpions (Šťáhlavský et al 2018b) and pseudoscorpions (Zaragoza and Šťáhlavský 2008). This is especially notable in some species of edaphic pseudoscorpions characterized by limited dispersal ability, for which distinct karyotypes may be found even in very close localities (Kotrbová et al 2016).…”