Hunting the wolf: A molecular phylogeny of the wolf spiders (Araneae, Lycosidae).

Lycosids are a diverse family of spiders distributed worldwide. Previous studies recovered some of the deeper splits of the family, but with little support. We present a broad phylogenetic analysis of the Lycosidae including a wide geographic sampling of representatives and all the subfamilies described to date. Additionally, we extend the amount of molecular data used in previous studies (28S, 12S and NADH) through the inclusion of two additional markers, the nuclear H3 and the mitochondrial COI. We estimated the divergence times through the inclusion of fossils as calibration points and used the phylogenetic hypothesis obtained to explore the evolution of particular traits associated with dispersal capabilities. We recovered most of the currently recognized subfamilies with high nodal support. Based on these results, we synonymize Piratinae and Wadicosinae with Zoicinae and Pardosinae, respectively, and revalidate the subfamily Hippasinae. We corroborated that lycosids are a family with a relatively young origin that diversified with the reduction of tropical forests and the advance of open habitats. We show that a gradual accumulation of behavioral traits associated with ambulatory dispersal made Lycosidae the most vagrant subfamily of spiders, with an impressive ability to disperse long distances which helps to explain the worldwide distribution of some very young clades, such as the members of the subfamily Lycosinae.

The spider tree of life: phylogeny of Araneae based on target-gene analyses from an extensive taxon sampling.

We present a phylogenetic analysis of spiders using a dataset of 932 spider species, representing 115 families (only the family Synaphridae is unrepresented), 700 known genera, and additional representatives of 26 unidentified or undescribed genera. Eleven genera of the orders Amblypygi, Palpigradi, Schizomida and Uropygi are included as outgroups. The dataset includes six markers from the mitochondrial (12S, 16S, COI) and nuclear (histone H3, 18S, 28S) genomes, and was analysed by multiple methods, including constrained analyses using a highly supported backbone tree from transcriptomic data. We recover most of the higher-level structure of the spider tree with good support, including Mesothelae, Opisthothelae, Mygalomorphae and Araneomorphae. Several of our analyses recover Hypochilidae and Filistatidae as sister groups, as suggested by previous transcriptomic analyses. The Synspermiata are robustly supported, and the families Trogloraptoridae and Caponiidae are found as sister to the Dysderoidea. Our results support the Lost Tracheae clade, including Pholcidae, Tetrablemmidae, Diguetidae, Plectreuridae and the family Pacullidae (restored status) separate from Tetrablemmidae. The Scytodoidea include Ochyroceratidae along with Sicariidae, Scytodidae, Drymusidae and Periegopidae; our results are inconclusive about the separation of these last two families. We did not recover monophyletic Austrochiloidea and Leptonetidae, but our data suggest that both groups are more closely related to the Cylindrical Gland Spigot clade rather than to Synspermiata. Palpimanoidea is not recovered by our analyses, but also not strongly contradicted. We find support for Entelegynae and Oecobioidea (Oecobiidae plus Hersiliidae), and ambiguous placement of cribellate orb-weavers, compatible with their non-monophyly. Nicodamoidea (Nicodamidae plus Megadictynidae) and Araneoidea composition and relationships are consistent with recent analyses. We did not obtain resolution for the titanoecoids (Titanoecidae and Phyxelididae), but the Retrolateral Tibial Apophysis clade is well supported. Penestomidae, and probably Homalonychidae, are part of Zodarioidea, although the latter family was set apart by recent transcriptomic analyses. Our data support a large group that we call the marronoid clade (including the families Amaurobiidae, Desidae, Dictynidae, Hahniidae, Stiphidiidae, Agelenidae and Toxopidae). The circumscription of most marronoid families is redefined here. Amaurobiidae include the Amaurobiinae and provisionally Macrobuninae. We transfer Malenellinae (Malenella, from Anyphaenidae), Chummidae (Chumma) (new syn.) and Tasmarubriinae (Tasmarubrius, Tasmabrochus and Teeatta, from Amphinectidae) to Macrobuninae. Cybaeidae are redefined to include Calymmaria, Cryphoeca, Ethobuella and Willisius (transferred from Hahniidae), and Blabomma and Yorima (transferred from Dictynidae). Cycloctenidae are redefined to include Orepukia (transferred from Agelenidae) and Pakeha and Paravoca (transferred from Amaurobiidae). Desidae are redefined to include five subfamilies: Amphinectinae, with Amphinecta, Mamoea, Maniho, Paramamoea and Rangitata (transferred from Amphinectidae); Ischaleinae, with Bakala and Manjala (transferred from Amaurobiidae) and Ischalea (transferred from Stiphidiidae); Metaltellinae, with Austmusia, Buyina, Calacadia, Cunnawarra, Jalkaraburra, Keera, Magua, Metaltella, Penaoola and Quemusia; Porteriinae (new rank), with Baiami, Cambridgea, Corasoides and Nanocambridgea (transferred from Stiphidiidae); and Desinae, with Desis, and provisionally Poaka (transferred from Amaurobiidae) and Barahna (transferred from Stiphidiidae). Argyroneta is transferred from Cybaeidae to Dictynidae. Cicurina is transferred from Dictynidae to Hahniidae. The genera Neoramia (from Agelenidae) and Aorangia, Marplesia and Neolana (from Amphinectidae) are transferred to Stiphidiidae. The family Toxopidae (restored status) includes two subfamilies: Myroinae, with Gasparia, Gohia, Hulua, Neomyro, Myro, Ommatauxesis and Otagoa (transferred from Desidae); and Toxopinae, with Midgee and Jamara, formerly Midgeeinae, new syn. (transferred from Amaurobiidae) and Hapona, Laestrygones, Lamina, Toxops and Toxopsoides (transferred from Desidae). We obtain a monophyletic Oval Calamistrum clade and Dionycha; Sparassidae, however, are not dionychans, but probably the sister group of those two clades. The composition of the Oval Calamistrum clade is confirmed (including Zoropsidae, Udubidae, Ctenidae, Oxyopidae, Senoculidae, Pisauridae, Trechaleidae, Lycosidae, Psechridae and Thomisidae), affirming previous findings on the uncertain relationships of the "ctenids" Ancylometes and Cupiennius, although a core group of Ctenidae are well supported. Our data were ambiguous as to the monophyly of Oxyopidae. In Dionycha, we found a first split of core Prodidomidae, excluding the Australian Molycriinae, which fall distantly from core prodidomids, among gnaphosoids. The rest of the dionychans form two main groups, Dionycha part A and part B. The former includes much of the Oblique Median Tapetum clade (Trochanteriidae, Gnaphosidae, Gallieniellidae, Phrurolithidae, Trachelidae, Gnaphosidae, Ammoxenidae, Lamponidae and the Molycriinae), and also Anyphaenidae and Clubionidae. Orthobula is transferred from Phrurolithidae to Trachelidae. Our data did not allow for complete resolution for the gnaphosoid families. Dionycha part B includes the families Salticidae, Eutichuridae, Miturgidae, Philodromidae, Viridasiidae, Selenopidae, Corinnidae and Xenoctenidae (new fam., including Xenoctenus, Paravulsor and Odo, transferred from Miturgidae, as well as Incasoctenus from Ctenidae). We confirm the inclusion of Zora (formerly Zoridae) within Miturgidae.

A taxonomic review of the wolf spider genus Agalenocosa Mello-Leitão (Araneae, Lycosidae).

The lycosid genus Agalenocosa Mello-Leitão, 1944 comprises at least eight species from northern and eastern Argentina and neighbouring countries: Agalenocosa velox (Keyserling, 1891) comb. nov. (from southern Brazil and Argentina), transferred here from Pirata Sundevall, 1833, A. tricuspidata (Tullgren, 1905) comb. nov. (from northwestern Argentina), transferred here from Pardosa C.L. Koch, 1847, A. luteonigra (Mello-Leitão, 1945) (from Argentina and Uruguay), A. punctata Mello-Leitão, 1944 (from Buenos Aires and Entre Ríos, Argentina),  A. gentilis Mello-Leitão, 1944 (from Buenos Aires, Argentina), and three new species: A. pirity sp. nov., A. gamas sp. nov. (from eastern Argentina), and A. grismadoi sp. nov. (from eastern Argentina and Paraguay). Agalenocosa singularis Mello-Leitão (type species of the genus) is considered a junior synonym of A. velox. Agalenocosa fimbriata Mello-Leitão, 1944 is considered species inquirenda; Agalenocosa bryantae (Roewer, 1951), A. chacoensis (Mello-Leitão, 1942), A. denisi (Caporiacco, 1947), A. kolbei (Dahl, 1908), A. melanotaenia (Mello-Leitão, 1941), A. pickeli (Mello-Leitão, 1937), A. yaucensis (Petrunkevitch, 1929), A. fallax (L. Koch, 1877), A. helvola (C. L. Koch, 1847), A. subinermis (Simon, 1897) are considered misplaced species.        The subfamily placement of Agalenocosa is briefly discussed, and it could be placed in either Piratinae Zyuzin, 1993 or Venoniinae Lehtinen & Hippa, 1979. 

The desert wolf-spider genus Xenoctenus: two endemic species from the Brazilian Caatinga, and a redescription of the type-species, X. unguiculatus (Araneae: Xenoctenidae).

The Caatinga is a nucleus of seasonally dry tropical forest (SDTF) known as a hotspot of diversification and endemism. Despite its importance, this biome is still insufficiently sampled, resulting in extensive knowledge gaps regarding its species richness and composition. In this study we report two species of Xenoctenidae that are endemic to, and widely distributed in the Caatinga. We redescribe and illustrate Odo vittatus (Mello-Leito, 1936), the only xenoctenid species previously known from the Caatinga. We transfer this species to Xenoctenus Mello-Leito,1938, a genus currently known from six species restricted to Argentina, Bolivia, and Colombia. We also newly describe the male of Xenoctenus vittatus comb. nov. and provide new records of this species, which was hitherto known only from the type-locality, throughout the Caatinga and nearby semiarid vegetation formations. We also describe and illustrate a new species, Xenoctenus kaatinga sp. nov., based on males and female specimens collected throughout the Caatinga. Additionally, we propose diagnostic characters for Xenoctenus and redescribe the type-species, X. unguiculatus.

The South American wolf spider genus Birabenia Mello-Leitão, 1941 (Araneae: Lycosidae: Lycosinae).

The wolf spider genus Birabenia Mello-Leitão, 1941 is revalidated, comprising B. birabenae Mello-Leitão (type species) and B. vittata (Mello-Leitão) comb. n. The monotypic genus Melloicosa Roewer is synonymised with Birabenia by the transfer of its type species Gnatholycosa vittata Mello-Leitão. Three species, Hogna taeniata (Mello-Leitão), Geolycosa sanogastensis (Mello-Leitão) and Paratrochosina murina (Mello-Leitão) are considered junior synonyms of B. birabenae. Representatives of Birabenia show affinities with Trochosa C. L. Koch but can be distinguished by the presence of one pair of apical spines or none on the ventral side of tibia I of females, the presence of four teeth on the cheliceral retromargin, a shorter furrow on the prolateral side of the tegulum on the male bulb and by having more than seven macrosetae at the tip of cymbium. Birabenia is distributed from north-western Argentina to southern Uruguay.

A new orb-weaving spider from the Argentinean flooding pampas grasses: Aculepeira morenoae new species (Araneae, Araneidae).

A new species of the orb-weaving spider genus Aculepeira Chamberling & Ivie 1942, A. morenoae new species, is described and illustrated based on male and female specimens from the Argentinean natural flooding pampas grasses.

The first palpimanid spiders from Bolivia: two new species of the genus Otiothops MacLeay, and the female of Fernandezina pulchra Birabén (Araneae: Palpimanidae: Otiothopinae).

The araneomorph spider family Palpimanidae is reported from Bolivia for the first time. Two new species: Otiothops kathiae and O. naokii are described and illustrated based on specimens recently collected in Santa Cruz Department. Additionally, Fernandezina pulchra Birabén, 1951 previously known only from Formosa, in northern Argentina, is newly recorded from Santa Cruz, and the female is described for the first time. Potential relationships with previously described species are also briefly discussed.

Copulatory mechanics of ghost spiders reveals a new self-bracing mechanism in entelegyne spiders.

Spiders evolved a distinctive sperm transfer system, with the male copulatory organs located on the tarsus of the pedipalps. In entelegyne spiders, these organs are usually very complex and consist of various sclerites that not only allow the transfer of the sperm themselves but also provide a mechanical interlock between the male and female genitalia. This interlocking can also involve elements that are not part of the copulatory organ such as the retrolateral tibial apophysis (RTA)-a characteristic of the most diverse group of spiders (RTA clade). The RTA is frequently used for primary locking i.e., the first mechanical engagement between male and female genitalia. Despite its functional importance, some diverse spider lineages have lost the RTA, but evolved an apophysis on the femur instead. It can be hypothesized that this femoral apophysis is a functional surrogate of the RTA during primary locking or possibly serves another function, such as self-bracing, which involves mechanical interaction between male genital structures themselves to stabilize the inserted pedipalp. We tested these hypotheses using ghost spiders of the genus Josa (Anyphaenidae). Our micro-computed tomography data of cryofixed mating pairs show that the primary locking occurs through elements of the copulatory organ itself and that the femoral apophysis does not contact the female genitalia, but hooks to a projection of the copulatory bulb, representing a newly documented self-bracing mechanism for entelegyne spiders. Additionally, we show that the femoral self-bracing apophysis is rather uniform within the genus Josa. This is in contrast to the male genital structures that interact with the female, indicating that the male genital structures of Josa are subject to different selective regimes.

Copulatory mechanics in the wolf spider Agalenocosa pirity reveals a hidden diversity of locking systems in Lycosidae (Araneae).

Genital traits are among the fastest to evolve, and the processes that drive their evolution are intensively studied. Spiders are characterized by complex genitalia, but the functional role of the different structures during genital coupling is largely unknown. Members of one of the largest spider groups, the retrolateral tibial apophysis (RTA) clade, are characterized by a RTA on the male palp, which is thought to play a crucial role during genital coupling. However, the RTA was lost in several families including the species-rich wolf spiders (Lycosidae) leading to the hypothesis that the genital coupling is achieved by alternative mechanisms. Here, we investigate the genital interactions during copulation in the wolf spider Agalenocosa pirity (Zoicinae) on cryofixed mating pairs using electron, optical and X-ray microscopy and compare our findings with other lycosids and entelegyne spiders. We found an unprecedented coupling mechanism for lycosid spiders involving the palea and a membranous cuticle folding adjacent to the epigynal plate. Additionally, we show an uncommon coupling between the median apophysis and the contralateral genital opening, and confirmed that the terminal apophysis acts as functional conductor, as previously hypothesized for males of Zoicinae. Phylogenetic mapping of RTA indicated that the basal tibial process found in Agalenocosa is a secondary acquisition rather than a modified RTA.

Wolf spider burrows from a modern saline sandflat in central Argentina: morphology, taphonomy and clues for recognition of fossil examples.

Pavocosa sp. (Lycosidae) burrows found in an open sparsely vegetated area on the edge of the Gran Salitral saline lake, in central Argentina, are described. Burrows were studied by capturing the occupant and casting them with dental plaster. The hosting sediments and vegetation were also characterized. Inhabited Pavocosa sp. burrows display distinctive features as open, cylindrical, nearly vertical, silk lined shafts about 120 mm long, subcircular entrances, a gradual downward widening, and a particularly distinctive surface ornamentation in the form of sets of two linear parallel marks at a high angle to the burrow axis. Instead, casts of vacated Pavocosa sp. burrows showed some disturbances caused either by the reoccupation by another organism or by predation of the dweller. Two morphologies are related to reoccupation of burrows: those with a structure in form of an "umbrella" and another with smaller excavations at the bottom of the burrow. Predation by small mammals produces funnel-shaped burrows. Both active and abandoned Pavocosa sp. burrow casts are compared with existing ichnogenera and inorganic sedimentary structures, highlighting its distinction. It is argued that key features like the presence of a neck, a downward widening and the described surface texture will allow recognition of wolf spider burrows in the fossil record. However, the putative spider burrows described in the literature either lack the necessary preservational quality or do not show ornamentation similar to the modern wolf spider burrows. Fossil wolf spiders are recorded since the Paleogene (possibly Late Cretaceous), therefore Cenozoic continental rocks can contain wolf spider burrows awaiting recognition. In addition, the particular distribution of Pavocosa sp. in saline lakes may imply that this type of burrow is linked to saline environments.