Chromosomal diversity in three species of Lycosa Latreille, 1804 (Araneae, Lycosidae): Inferences on diversification of diploid number and sexual chromosome systems in Lycosinae.

Lycosa is one of the most speciose genera in Lycosidae, including species with different sexual chromosome systems (SCS). We carried out cytogenetic analyses in three species of Lycosa, revealing that L. erythrognatha and L. sericovittata share 2n ♂ = 22 and SCS X1X20 while L. gr. nordenskjoldi presents 2n ♂ = 19 and SCS XO, composed only of acrocentric chromosomes. All species shared pericentromeric heterochromatin. Nonetheless, one specimen of L. sericovittata carried two chromosomes with terminal heterochromatin and L. gr. nordenskjoldi showed four chromosomes with interstitial heterochromatin plus another chromosome with terminal C-bands. The pericentromeric heterochromatin of all species as well as the terminal heterochromatic blocks in L. sericovittata were CMA3+. The 18S rDNA sites varied in number and type of bearing chromosomes both at inter and intrapopulational levels, with the highest variation in L. gr. nordenskjoldi. These differences may be related to gene dispersal due to the influence of transposition elements and translocation events. Despite these variations, all species shared ribosomal sites in pair 5. This study demonstrated intra and interspecific chromosomal variability of Lycosa, suggesting that chromosomal rearrangements are related to the diversification of diploid number and SCS in this group of spiders.

Venomous Loxosceles Species (Araneae, Haplogynae, Sicariidae) from Brazil: 2n♂ = 23 and X1X2Y Sex Chromosome System as Shared Characteristics.

The family Sicariidae comprises the genera Hexophthalma, Sicarius and Loxosceles. This latter is subdivided in eight monophyletic groups based on genitalia morphology and molecular analyses: amazonica, gaucho, laeta, and spadicea (South America); reclusa (North America); rufescens (Mediterranean); spinulosa and vonwredei (Africa). In Brazil, the genus Loxosceles is represented by 50 species. The mitotic and meiotic characteristics of eight Loxosceles species were analyzed in order to discuss the chromosome evolution, as well as the correspondence between cytogenetic data and morphological/molecular data for the delimitation of the South American groups of species belonging to this genus. All species studied in this work showed 2n♂ = 23, including a X1X2Y sex chromosome system (SCS). Despite the similarity of diploid number and SCS, the species studied here differed regarding the chromosome morphology of some autosomal pairs, presence of secondary constrictions, size of X chromosomes and localization of Ag-NOR/rDNA sites. Based on all these chromosomal data, we verified a close relationship between Loxosceles species belonging to the amazonica and gaucho groups. Transmission electron microscopy (TEM) analysis of spread pachytene cells of L. gaucho showed regular synapsis between homologous autosomal chromosomes, but asynaptic behavior of the sex chromosomes. The axial elements of the sex chromosomes undergo conspicuous morphological modifications resulting in shortening of their length.

Comparative cytogenetics of seven Ctenidae species (Araneae).

The present study elevates the number of cytogenetically analyzed ctenid species and genera from two to eight and six, respectively, presenting comparisons between chromosomal data obtained and the phylogenetic hypothesis proposed in the literature. Six ctenid species presented 13 autosomal pairs, exhibiting either X1X2O (Ctenus ornatus, Ctenus sp., Parabatinga brevipes and Phoneutria nigriventer) or X1X2X3O sex chromosome systems (Nothroctenus sp. and Viracucha andicola). Asthenoctenus borellii showed 2n ♂ = 20 + X1X2O. In all species, the chromosomes were telocentric. Some cells of one C. ornatus specimen exhibited one extra chromosome that, considering the behavioral similarities between the two chromosomes, can be considered to be supernumerary, derived from or giving rise to a sex chromosome. Silver impregnation revealed nucleolar organizer regions on one autosomal pair of C. ornatus and P. nigriventer (Cteninae) and two pairs of V. andicola (Acanthocteninae). Chromosomal data suggests that the X1X2X3O system arose several times in the evolution of entelegyne spiders, and that conversion of an X1X2O system into an X1X2X3O system and vice-versa has been a relatively common event in spiders. All the chromosomal data corroborate the close relationship between Ctenus and Phoneutria, the placement of P. brevipes within Cteninae, the placement of Anahita in a separated branch within Cteninae, and the inclusion of A. borellii in a distinct group within the ctenids (Viridasiinae), all of which are as proposed by phylogenetic hypotheses available in the literature.

Chromosomal Study on Selected Small Araneomorph Spiders from Brazil, Including the First Records in Palpimanidae and Theridiosomatidae (Araneae, Araneomorphae).

Among the 50,474 spider species, only 849 have chromosomal data available in the literature. Fifty spider families remain unknown from a cytogenetic perspective. The aim of this study was to analyze chromosomally selected araneomorph spiders from Brazil, to contribute to the cytotaxonomy and chromosome evolution of this group. The karyotypes of 12 species belonging to families Corinnidae, Linyphiidae, Oonopidae, Palpimanidae, Theridiidae, Theridiosomatidae, Trachelidae, and Zodariidae were analyzed, including the first chromosomal record for the first two families. Specimens (with the abdomen content partially exposed by perforation) were subjected to colchicine, hypotonization, and fixation. In most cases, the total content of the abdomen was used to prepare slides by spreading of cell suspension and subsequent Giemsa staining. The results were as follows: Cinetomorpha simplex Simon, 1892 (Oonopidae) 2n♂ = 9, X0; Neotrops sp. and Neoxyphinus termitophilus (Oonopidae), 2n♂ = 7, X0; Otiothops birabeni (Palpimanidae); Agyneta sp. (Linyphiidae), 2n♂ = 24, X1X20; Coleosoma floridanum, Thymoites sp.1 and Thymoites sp.2 (Theridiidae), 2n♂ = 22, X1X20; Naatlo sp. (Theridiosomatidae), 2n♂ = 30, X1X20; Orthobula sp. (Trachelidae) 2n♂ = 21, X0; Falconina sp. (Corinnidae), 2n♂ = 28, X1X20; Epicratinus sp. (Zodariidae) 2n♂ = 42, X1X20. The chromosomal morphology was determined for all the samples except for Oonopidae. Most species exhibited telocentric chromosomes, with the exception of Palpimanidae and Theridiosomatidae. The main findings: 1) support an hypothesis on ancestral karyotype of Zodariidae and Oonopidae; 2) reveal a relatively high chromosome number in Palpimanidae that supports an idea on relatively high ancestral chromosome number (2n♂ = 42) of entelegyne spiders (Palpimanoidea is sister group of entelegyne spiders); 3) show that the karyotype found in Theridiosomatidae is exceptional within the Araneoidea.

Taxonomic notes, distribution update and the first chromosomal analysis of Vectius niger (Simon, 1880) and Trochanteria gomezi Canals, 1933 (Araneae: Trochanteriidae).

Spiders of the family Trochanteriidae are characterized by the carapace being extremely flat, with a reflex border, medium posterior eyes flattened, laterigrade legs, the absence of claw tufts, anterior lateral spinnerets with an incomplete distal article, and an inflatable and epiginal plate formed by a divided plate. Two out of the six worldwide genera of Trocantheriids have species in the Brazilian areas: Trochanteria Karsch and Vectius Simon. Here we present the redescription of Vectius niger and morphological data of Trochanteria gomezi, with an expansion of the distribution of these species in the Neotropical region and unpublished chromosomal data of both species. Mitotic and meiotic cells of both T. gomezi and V. niger showed 2n=22 and 2n=24 telocentric chromosomes, with a sex chromosome system of the type X1X2 in males/X1X1X2X2 in females. The chromosomal data shown here matches those found in trochanteriids to date.

A new species of Pinelema Wang & Li, 2012, a relictual telemid spider inhabiting caves in Brazil (Araneae, Telemidae).

A new species of the genus Pinelema Wang & Li, 2012, occurring in caves of the state of Bahia in Northeastern Brazil, is described and illustrated. This species has the typical troglobitic characters, such as the absence of eyes, elongation of legs and setae, and pale, almost depigmented, somatic coloration. Data on the natural history of populations of P. elinae sp. nov. from caves in the Serra do Ramalho, State of Bahia, are presented. This work represents the first description of a relictual species of Telemidae spiders in Brazil.

The more, the merrier: a new colonial species of the orb weaving spider genus Leucauge White, 1841 (Araneae: Tetragnathidae) from the Amazon rainforest.

A new Leucauge species, widespread in the Amazon rainforest, is described and illustrated. Leucauge behemoth n. sp. lives in colonies, usually positioned above turbulent waters. Both males and females have a unique color pattern, especially on the abdomen, which makes this species easily identifiable. Males are distinguished from most congeners by the long hook of the cymbium and from their closest relatives by the lack of a cymbial dorsobasal process. Females of this species differ from their congeners by the presence of a rounded ventral process in the epigynum. Leucauge argyroaffins Soares & Camargo, 1948 is proposed as a junior synonym of Leucauge argyra (Walckenaer, 1841).

Three new subterranean species of the genus Speocera (Araneae, Ochyroceratidae) from caves of the Carajs area in the state of Par, Brazil.

Three new species of the spider genus Speocera Berland, 1914, collected in ferruginous caves in the Carajs region of Par state, Brazil are described: Speocera pinima sp. nov., S. babau sp. nov. and S. piquira sp. nov., all based on males and females. These are abundant species, which have morphological characteristics probably associated with isolation in the subterranean environment. Variation in the shape of the lateral eyes, which can be reduced, and in the eyes colloration bright or opalescent, were observed in all species in this study. These morphological variations may indicate that some populations are in the process of isolation and/or are distributed in different horizons of the subterranean environment, including the Milieu Souterrain Superficiel (MSS). An update of male and female genital structures and specializations to the subterranean environment are discussed.

Sandalodesmus joachimadisi n. sp., the first Chelodesmidae member from Uruguay with an updated key to species of the genus (Diplopoda: Polydesmida).

A new species of Chelodesmidae is described from northern Uruguay, Sandalodesmus joachimadisi n. sp. The new species differs from other congeners by particular features of the gonopods. Sandalodesmus joachimadisi n. sp. belongs to the iguazuensis species group. Photographs of the new species, data on its natural history and a geographic distribution map of all Sandalodesmus species are presented. A key to the species of Sandalodesmus is provided. The taxonomic relationships with other species of the genus are discussed.

Two New Species of the Brazilian Millipede Genus Rhicnosthetus Hoffman, 2006 (Polydesmida: Chelodesmidae), Including a Key to Males.

The genus Rhicnosthetus Hoffman, 2006 is revisited. Two new species from state of Mato Grosso, Brazil are described: Rhicnosthetus chagasi sp. nov. and Rhicnosthetus penabarbosai sp. nov. In addition, a new record for R. rondoni Hoffman, 2006, a key to males and a distribution map of all species are included.

Cladistic analysis and taxonomic review of the millipede tribe Arthrosolaenomeridini Hoffman, 1976 (Polydesmida: Chelodesmidae).

Chelodesmidae is one of the most diverse families belonging to the Polydesmida, comprising almost 800 described species distributed in 172 genera, 20 tribes and two subfamilies. Among the tribes within the Neotropical subfamily Chelodesminae, Arthrosolaenomeridini represents a very interesting group occurring in the Central-West region of Brazil. Currently the tribe contains three genera: Arthrosolaenomeris Schubart, 1943, Gangugia Schubart, 1947, and Angelodesmus Schubart, 1962. In this study, we conducted a cladistic analysis including 18 species of Arthrosolaenomeridini and 7 species of other associated Chelodesminae tribes as an outgroup. The matrix is composed of 64 morphological characters from which 39 are herein proposed for the first time. The data were analyzed under the parsimony criterion using TNT 1.5. Based on the results, Arthrosolaenomeridini was recovered as monophyletic with Macrocoxodesmini + Telonychopodini as sister group. Arthrosolaenomeris Schubart, 1943 and Gangugia Schubart, 1947 were recovered as monophyletics. The genus Angelodesmus Schubart, 1962 was recovered as paraphyletic and redefined as monotypic. The tribe is now composed of the genera Arthrosolaenomeris (6 spp.), Gangugia (6 spp.), Angelodesmus (monotypic), Abiliodesmus n. gen. (4 spp.) and Folcloredesmus n. gen. (monotypic). In addition, we conduct a taxonomic revision of the tribe Arthrosolaenomeridini providing detailed redescriptions, drawings, and distribution maps for all species and genera, including the two new genera and the ten new species proposed: Arthrosolaenomeris saci n. sp.; A. curupira n. sp.; A. caipora n. sp.; A. iara n. sp.; Gangugia boitata n. sp.; G. cuca n. sp.; G. boto n. sp.; G. mula n. sp.; Abiliodesmus mapinguari n. sp. and Folcloredesmus thomasi n. sp. Furthermore, we include an identification key to all the genera and species.

First chromosomal analysis in Deinopidae (Araneae) reveals Sex Chromosome System X1X2X3X4, B chromosomes and polymorphism for centric fusion.

Here we present the first cytogentic study concerning Deinopidae and their controversial phylogenetic position. This study karyologically analyzed one population of Deinopis biaculeata Simon, 1906 and five populations of Deinopis plurituberculata Mello-Leitão, 1925. The majority of specimens of D. plurituberculata exhibited 2n♂ = 40 and 2n♀ = 44 telocentric chromosomes (however some of them showed B chromosomes, belongs to Aquidauana and Botucatu population). The Deinopis biaculeata and D. plurituberculata meiosis of males showed 18 autosomal bivalents + X1X2X3X4, n = 22 and n = 18, a rare sex chromosome system (SCS) in spiders. Some individuals of D. plurituberculata from the Campo Grande population exhibited 2n♂ = 39 and 2n♀ = 43, with a metacentric chromosome (heterozygotes for centric fusion). The D. plurituberculata males with the rearrangement exhibit diplotenes with 16 autosomal bivalents + 1 autosomal trivalent + X1X2X3X4 and metaphases II with n = 22 (18 telocentric autosomes + X1X2X3X4), n = 21 (16 telocentric autosomes + a metacentric autosome + X1X2X3X4), n = 18 (18 telocentric autosomes) and n = 17 (16 telocentric autosomes + a metacentric autosome). The Ag-NORs (silver impregnation) are terminally located in a pair, coinciding with secondary constriction, which is the most common configuration for Araneae. The relatively high diploid number in Deinopis corroborates phylogenies that place it in a basal position among Entelegynes, in the UDOH grade (Uloboridae, Deinopidae, Oecobiidae and Hersiliidae). Centric fusion in only one population of D. plurituberculata suggests low dispersion capacity of this species and an absence of homozygotes for fusion suggests their low viability or a need to increase the population sampling of D. plurituberculata exhibiting the rearrangement. B chromosomes were detected in D. plurituberculata, with interpopulacional, intrapopulacional and intraindividual numerical variation, with cells presenting 0 - 3 and 0 - 6 B chromosomes in populations of Aquidauana and Botucatu, respectively.

Two new species of the armored spider genus Tetrablemma O. P.-Cambridge, 1873 from northern South America (Araneae: Synspermiata: Tetrablemmidae).

Two new species of the armored spider genus Tetrablemma O. P.-Cambridge, 1873 from Colombia and Venezuela are herein described and illustrated: Tetrablemma tatacoa sp. nov. from Huila department, Colombia and T. mochima sp. nov. from Sucre state, Venezuela. These species represent the second record of the genus in the New World. Specimens of these new species were collected in pristine ecosystems, which suggests a natural Gondwanan distribution of the genus. Additionally, a distribution map of the Tetrablemma species in America is herein included.

Taxonomic review and cladistic analysis of Neotropical spider genus Epicratinus Jocqué Baert, 2005 (Araneae: Zodariidae) with description of eleven new species.

A taxonomic revision and phylogenetic analysis of the spider genus Epicratinus Jocqué Baert, 2005 is presented. The phylogenetic analysis is based on a data set including 16 Epicratinus species plus 9 outgroups representing by five related zodariid gen-era and one of them considered most basal as the root. These taxa were scored for 49 morphological characters. Parsimony was used as the op-timality criterion and a sensitivity analysis was performed using different character weighting concavities. Five unambiguous synapomorphies support the monophyly of Epicratinus. Some internal clades within the genus are well-supported and their relationships are discussed. Epicratinus includes 16 species, all with males and females. A species identification key and distribution maps are provided for all. New morphological data are also pre-sented for five previously described species. All 16 species occur only in the New World. The following species are transferred to Epicratinus: E. perfidus (Jocqué Baert), comb. nov. from Tenedos; Epicratinus perfidus Jocqué Baert comb. nov. and newly synonymized with E. santacruz Grismado Izquierdo and this last species is treated as the junior synonym. Epicratinus petropolitanus (Mello-Leitão) has the male described for the first time. The following 11 species are newly described as new: E. zangief sp. nov.; E. pegasus sp. nov.; E. pikachu sp. nov.; E. stitch sp. nov.; E. ehonda sp. nov.; E. anakin sp. nov.; E. vader sp. nov.; E. omegarugal sp. nov.; E. zelda sp. nov.; E. dookan sp. nov. and E. mauru sp. nov., all from Brazil.

Insights on repetitive DNA behavior in two species of Ctenus Walckenaer, 1805 and Guasuctenus Polotow and Brescovit, 2019 (Araneae, Ctenidae): Evolutionary profile of H3 histone, 18S rRNA genes and heterochromatin distribution.

Ctenidae represents one of the most representative spider families in the tropical forests of Brazil. Its largest genus, Ctenus, has approximately 220 species out of the more than 520 Ctenidae species described, and several authors consider it polyphyletic. Chromosomal data are only available for four species of Ctenus, representing a large gap in the cytogenetic knowledge about the group. This study provided cytogenetic data on two Ctenus species and one Guasuctenus (previously described as Ctenus). All showed 2n♂ = 28 (26+X1X20). Guasuctenus longipes presented two chromosome pairs containing 18S rDNA genes and C. medius, however C. ornatus showed only one chromosome pair with the 18S rDNA gene. Hybridization data using histone H3 probe indicated specific profiles: histone H3 genes were found in one chromosome pair in G. longipes, in three pairs in C. medius, and in four pairs in C. ornatus. Furthermore, supernumerary chromosomes were identified in C. ornatus presenting a meiotic behavior similar to that of sex chromosomes; and a trivalent was found in C. medius, formed by the association of one sex chromosome and an autosomal bivalent, indicating the importance of these events for the diversification of sex chromosomes in spiders. The C-banding pattern was similar between C. medius and C. ornatus with regard to the number and locations of heterochromatic bands, suggesting that heterochromatin amplification and dispersion, affect karyotypic evolution in the genus. Cytogenetic data showed similarity between C. medius and C. ornatus, and differentiation of G. longipes congruent with morphological data. Moreover, although more comparative analyses are needed to specify composition of the dispersed heterochromatin in Ctenus, the mapping of heterochromatic bands provided insights about the evolution of the karyotypes in this genus.

Two new species of the ghost spider genus Macrophyes O. Pickard-Cambridge, 1893 from Colombia and description of the first male of Mesilla Simon, 1903 (Araneae: Anyphaenidae: Anyphaeninae).

Two new species of the elongated-body ghost spider genus Macrophyes O. Pickard-Cambridge, 1893 from Colombia are herein described and illustrated: Macrophyes sanzi n. sp. known by both sexes from Chocó department and Macrophyes ceratii n. sp. by females from Santander department. Additionally, the male of Mesilla vittiventris Simon, 1903 is described for the first time based on specimens from Nariño and Cauca departments, Colombia. A distribution map for the species herein reported is included.

The first record of Sicarius rugosus (F. O. Pickard-Cambridge, 1899) (Araneae: Haplogynae: Sicariidae) for Honduras, with comments on its natural history

Sicarius rugosus (F. O. Pickard-Cambridge, 1899) is recorded for the first time in Honduras, with the record of three males and eight immatures collected in the town of Pespire, department of Choluteca, in the south of the country. We also recorded the species from the study of an exuvia collected in the department of Comayagua. A revised diagnosis, photographs of the males, distribution map, as well as information on the natural history of this species in Honduras, are provided.

Revision of Neotropical wolf spider genus Arctosa C.L. Koch, 1847 (Araneae: Lycosidae), with description of seven new species

The genus Arctosa C.L. Koch is redescribed and diagnosed. Seven new species are described, four of them based on both sexes (A. conflicta sp. nov., A. costenola sp. nov., A. jibarosa sp. nov. and A. villa sp. nov.), two only on females (A. ayaymama sp. nov. and A. mineira sp. nov.), and one only on the male (A. pacaya sp. nov.). We also propose the transference of Arctosa humicola (Bertkau, 1880) and Arctosa fusca (Keyserling, 1877) to Trochosa C.L. Koch, 1847, and the new synonymy of Arctosa inconspicua (Bryant, 1948) with Trochosa humicola (Bertkau, 1880) comb. nov. Besides, Arctosa andina (Chamberlin, 1916) and Arctosa pugil (Bertkau, 1880) are transferred to Hogna Simon, 1885, and Arctosa aussereri (Keyserling, 1877) to Prolycosides Mello-Leitão, 1942. Additionally, eight lycosid species are synonymized with Prolycosides aussereri: Schizocosa proletaria (Tullgren, 1905); Arctosa workmani (Strand, 1909); Hogna planithoracis (Mello-Leitão, 1938); Hogna variolosa (Mello-Leitão, 1941); Megarctosa melanostoma (Mello-Leitão, 1941); Hippasosa huachoi (Mello-Leitão, 1942); Pirata abalosi (Mello-Leitão, 1942); and Pirata soukupi (Mello-Leitão, 1942). We also transfer Trochosa tenebrosa Keyserling, 1877 to Arctosa. The males of Arctosa tenebrosa (Keyserling, 1877) comb. nov. and Trochosa humicola (Bertkau, 1880) comb. nov. are described for the first time.

On the spider genus Cryptachaea from Peru, Bolivia and cave environments in Brazil: a new species, additional descriptions and new records (Araneae, Theridiidae).

In this paper a new species of Cryptachaea Archer, 1946 based on males and females is described from Brazilian caves: Cryptachaea pilar Santanna Rodrigues, new species from the states of Minas Gerais and São Paulo. The females of Cryptachaea parana (Levi, 1963) and C. schneirlai (Levi, 1959) are described and illustrated for the first time. Cryptachaea uviana (Levi, 1963) is synonymized with C. migrans (Keyserling, 1884). The species Cryptachaea alacris (Keyserling, 1884), C. benivia Rodrigues Poeta, 2015, C. parana (Levi, 1963) and C. schneirlai (Levi, 1959) are recorded for the first from Brazil; and C. migrans for the first time from Bolivia. Additionally, new records from Brazilian caves are provided for Cryptachaea parana, from the states of Tocantins, Goiás, Minas Gerais, Mato Grosso do Sul and São Paulo; C. schneirlai and C. alacris from the state of Pará; C. dea (Buckup Marques, 2006) and C. rioensis (Levi, 1963) from Pará and Minas Gerais, C. jequirituba (Levi, 1963) from Minas Gerais and C. benivia from São Paulo.

The tiniest violin: the male of Loxosceles vallenar (Araneae, Sicariidae)

In recent years, several endemic species of Loxosceles, violin spiders, have been described from the North-Central Chile biodiversity hotspot, some of which have ambiguous placement within the species groups of the genus. In a recent expedition to the Atacama region, we collected male specimens representing new records of two recently described species: Loxosceles vicentei Taucare-Ríos, Brescovit & Villablanca, 2022 and Loxosceles vallenar Brescovit, Taucare-Ríos, Magalhaes & Santos, 2017 (Araneae, Sicariidae). Males of the latter are hitherto unknown and are here described for the first time. Examination of the morphology of these species revealed characters such as an embolic keel and digitiform median receptacles, which suggest they do not belong in the laeta species group, but rather in the spadicea species group, which is briefly re-diagnosed. With carapace lengths smaller than 2 mm, the newly discovered males of L. vallenar are the tiniest members of the genus. In addition, males of this species bear strong macrosetae in the clypeus, a sexually dimorphic character not previously reported in Loxosceles.