MicroCT analysis unveils the role of inflatable female genitalia and male tibial complex in the genital coupling in the spider genus Aysha (Anyphaenidae, Araneae).

Sperm transfer in spiders is achieved by copulatory organs on the male pedipalps (i.e., copulatory bulbs), which can be simple or a complex set of sclerites and membranes. During copulation, these sclerites can be used to anchor in corresponding structures in the female genitalia by means of hydraulic pressure. In the most diverse group of Entelegynae spiders, the retrolateral tibial apophysis clade, the female role in the coupling of genitalia is considered rather passive, as conformational changes of the female genital plate (i.e., the epigyne) during copulation are scarce. Here, we reconstruct the genital mechanics of two closely related species belonging to the Aysha prospera group (Anyphaenidae) that bear a membranous, wrinkled epigyne and male pedipalps with complex tibial structures. By using microcomputed tomography data of a cryofixed mating pair, we reveal that most of the epigyne remains greatly inflated during genital coupling, and that the male tibial structures are coupled to the epigyne by the inflation of a tibial hematodocha. We propose that a turgent female vulva is a prerequisite for the genital coupling, which could implicate a female control device, and that the structures from the male copulatory bulb have been functionally replaced by tibial structures in these species. Furthermore, we show that the conspicuous median apophysis is maintained in spite of being functionally redundant, posing a puzzling situation.

Abaycosa a new genus of South American wolf spiders (Lycosidae: Allocosinae)

The taxonomy and systematics of the subfamily Allocosinae are poorly known, especially in South America. In the last century, several species have been described in genera from other subfamilies or transferred to them creating great confusion in the knowledge of Allocosinae. In this study we propose the new genus, Abaycosa gen. nov. to contain two species previously described, Orinocosa paraguensis (Gertsch & Wallace 1937) and Pardosa nanica Mello-Leitão 1941. Additionally, we propose two synonyms, Pardosa flammula Mello-Leitão 1945 as a junior synonym of Abaycosa nanica (Mello-Leitão 1941), comb. nov. and Alopecosa rosea Mello-Leitão 1945 as a junior synonym of Abaycosa paraguensis (Gertsch & Wallace 1937), comb. nov. The results of the phylogenetic analysis using molecular characters place Abaycosa in the subfamily Allocosinae, which is also supported by morphological data. Abaycosa can be distinguished from the remaining Allocosinae by the following characters: in males by the presence of only one distal macrosetae and a patch of flat setae on the tip of the cymbium, in females by the ventral position of the vulval chamber and by the short and stout stalk of the spermathecae.

A revision of the wolf spider genus Diapontia Keyserling, and the relationships of the subfamily Sosippinae (Araneae: Lycosidae)

The South American genus Diapontia is revised to include nine species: Diapontia uruguayensis Keyserling, 1877 (= Diapontia senescens Mello-Leitao, 1944 syn. n.; D. infausta Mello-Leitao, 1941 syn. n.; D. pourtaleensis Mello-Leitao, 1944 syn. n.; D. albopunctata Mello-Leitao, 1941 syn. n.) from northern Paraguay, southeastern Brazil, southern Uruguay, southern to northeastern Argentina and southern Chile; D. niveovittata Mello-Leitao, 1945 from southern Paraguay, north-central Argentina and southern Brazil; D. anfibia (Zapfe-Mann, 1979) comb. n. (= Lycosa artigasi Casanueva, 1980 syn. n.) from central and southern Chile and southwestern Argentina, transferred from Pardosa C. L. Koch, 1847; D. securifera (Tullgren, 1905) comb. n. from northern Chile and northwestern Argentina, transferred from Orinocosa Chamberlin, 1916; D. arapensis (Strand, 1908) comb. n., from Peru, transferred from Hippasella Mello-Leitao, 1944; D. calama sp. n. from northern Chile; D. songotal sp. n. from southern Bolivia; D. chamberlini sp. n. from central and southern Peru; and D. oxapampa sp. n. from northern Peru. The sister-group relationship between Diapontia and Hippasella, and their placement in the subfamily Sosippinae, were supported by phylogenetic analyses based on four molecular markers (28S, 12S, NADH1 and COI), using Bayesian inference and maximum-likelihood. We tested whether DNA barcoding techniques were able to corroborate the identity of four Diapontia species. Diapontia securifera and D. anfibia were successfully identified using COI; however, D. niveovittata and D. uruguayensis were found to share identical haplotypes and thus could not be discriminated.