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Toxic metal pollution in the Amazon is a serious problem that reduces the quality of water, soil, air, and consequently alters communities of fauna, flora, and microbiota, harming human health and well-being. Our aim was to determine the impact of toxic metals on the structure of the bacterial community associated with Diplopoda in the Amazon rainforest. Animals were kept in microcosms contaminated with cadmium (50 mg.kg -1 ), mercury (35 mg.kg -1 ) and no toxic metal (control). The intestinal and molting chamber microbiota were accessed by culture-dependent and culture-independent methods (16S metabarcoding). The cultivated strains were identified, and their functional traits evaluated: secretion of enzymes, growth at different pH, resistance to metals and antibiotics, and ability to reduce toxic effects of metals on plants. Our research described Brachyurodesmus albus, a new species of Diplopoda. We obtained 177 isolates distributed in 35 genera and 61 species of bacteria (Pseudomonadota, Bacillota, Bacteroidota and Actinomycetota) associated with the gut and molting chamber of B. albus. Metabarcoding data provided a more robust access to the bacterial community, resulting in 24 phyla, 561 genera and 6792 ASVs. The presence of metal Cd and Hg alters the composition and abundance of bacteria associated with B. albus (PERMANOVA p < 0.05). The microhabitat (gut and molting chamber) harbours bacterial communities that differ in composition and abundance (PERMANOVA p < 0.05). The presence of Cd and Hg alters important metabolic pathways related to the prokaryotic defense system; antimicrobial resistance genes, endocytosis and secretion system, estimated by PICRUSt. Bacteria selected with high resistance to Cd and Hg buffer the toxic effect of metals on tomato seedlings. This work describes B. albus and concludes that its diverse bacterial microbiota is altered by soil contamination by toxic metals, as well as being an important repository for prospecting strains to be applied in bioremediation programs., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Habitat selection by spiders is strongly influenced by biotic factors such as the availability and diversity of prey and abiotic factors such as temperature, humidity, and the structural complexity of the habitat. Structural complexity is an aspect that intensely affects species persistence, population stability, and the coexistence of interacting species. Trees comprise a complex set of microhabitats due to their large biomass and heterogeneity of the architectural components of their trunk surface and branches. Spider species that live on trunks have diversified physiological or morphological adaptations that confer advantages in this environment. In this study, we experimentally examined the habitat choice by the tree-dwelling spiders Selenops cocheleti (Selenopidae), Corinna rubripes (Corinnidae), and Loxosceles gaucho (Sicariidae). We found that microhabitat specialization was restricted to trunk architectural characteristics rather than plant taxonomy. Selenops cocheleti and C. rubripes significantly preferred loose barks and holes in the trunks, respectively, showing that both spider species can evaluate the physical structure of the microhabitat on a fine scale. On the other hand, L. gaucho selected crevices and holes near the base of the trunk without giving much importance to the physical characteristics of the microhabitat per se (e.g., depth, height, length). Our findings indicate that for generalist predators like spiders, coexistence relies heavily on spatial segregation driven by distinct habitat preferences, irrespective of their method for capturing prey., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Sicariidae is a small family of cryptic and recluse spiders, with 178 species grouped into three genera: Hexophtalma, Loxosceles and Sicarius . Only the last two occur in Brazil, where 29 species are recorded, with a greater number of records in the Southeast and South regions. To date, there is no regionalized study of the distribution of these spiders in the Northeast of Brazil. We presented more than four decades of data on the distribution of sicariid spiders in the state of Bahia. Our research aimed to identify and evaluate the distribution of sicariid species in this region, characterizing them in their biomes and phytophysiognomies., Methods: Data covers a period from 1983 to 2024, obtained from articles describing species recorded in Bahia and from three scientific collections from Brazilian institutions: Universidade Federal da Bahia (MHNBA); Instituto Butantan (IBSP); Universidade Federal de Minas Gerais (UFMG). Maps were produced using the QGIS 3.34.1 software, based on geographic coordinates obtained from the original literature, when provided. Species without information on geographic coordinates were georeferenced using the SpeciesLink (geoLoc tool) for the municipalities. Biomes were consulted on the georeference Brazilian institute website and the phytophysiognomies were ignored when not specified in the data of collections or original literature., Results: We confirmed 14 species of sicariid spiders in the state of Bahia, eight from the genus Loxosceles (i) and six from Sicarius . The species were recorded in 48 municipalities, located mainly in the Caatinga biome. We recorded a distribution expansion of seven species: Loxosceles amazonica, L. chapadensis, L. karstica, L. similis, Sicarius cariri, S. ornatus and S. tropicus . There is a difference in species composition in the two regions separated by the São Francisco River, an important geographic barrier especially for small invertebrates. More than 75% of the species were registered in the east side and about 20% exclusively in the west side: L. boqueirao, L. cardosoi, L. carinhanha . This suggests the need for future studies to evaluate additional variables that determine community structure, especially considering their low vagility and reclusive behavior. Although Sicarius are found almost exclusively in the Caatinga, there are isolated records from Restinga and dry forest enclaves in the Cerrado domain and Atlantic Forest areas. This reinforces the possibility of them being able to adapt to slightly wetter environments erase colonize and survive in seasonally dry rainforest areas. Unlike Sicarius (i), Loxosceles (i) occupy a wide variety of habitats in natural, urban and domiciliary situations. Many of the records here such as for Loxosceles boqueirao, L. cardosoi, L. carinhanha, L. chapadensis, L. karstica and L. troglobia were obtained at caves or nearby areas, which appear to be attractive habitats for these nocturnal spiders., Competing Interests: The authors declare there are no competing interests., (©2024 Andrade-de-Sá et al.)

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: Loxoscelesvicentei Taucare-Ríos, Brescovit & Villablanca, 2022 and Loxoscelesvallenar 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 ., Competing Interests: The authors have declared that no competing interests exist., (Ivan L. F. Magalhaes, Hernán A. Iuri, Antonio D. Brescovit, Jaime Pizarro-Araya.)

In this paper, we describe three new species of Paracymbiomma Rodrigues, Cizauskas & Rheims, 2018 and the female of P. pauferrense Rodrigues, Cizauskas & Rheims, 2018. Two species are restricted to the iron caves of the Carajás Speleological Unit, in the state of Pará, Brazil: Paracymbiomma pepita sp. nov. (male, female), from Serra Leste, Curionópolis and P. otxurucu sp. nov. (male, female) from Serra Sul, Canaã dos Carajás and Parauapebas. Paracymbiomma una sp. nov. (male, female) is described from Reserva Biológica do Una, Una, Bahia, Brazil. In addition, we list additional material collected in caves and deposited in arachnological collections in Brazil, provide an identification key and updated distribution map for all known species of the genus.

The genus Plato Coddington, 1986 is revised and now contains twelve Neotropical species. The male of Plato bicolor (Keyserling, 1886) is described for the first time from the state of Amazonas in Brazil. Three new species are described: Plato omnipraesens n. sp. (♂ ♀) from Brazil and Peru, Plato peruana n. sp. (♀) from Peru and Plato hamatus n. sp. (♂ ♀) from Minas Gerais in Brazil. A new diagnosis is proposed for the females of this genus. Morphological structures and genitalic terminology are discussed. Plato species are described, diagnosed, illustrated, and their geographic distribution is mapped.

A new troglobitic species of Chelodesmidae, Cayenniola albaserrata n. sp., from the Água Clara cave system, Caatinga Domain, Bahia, Brazil is described. The new species is only the sixth known troglobitic chelodesmid, the first troglobitic species in the Priodesmini, and the first member of the tribe recorded from the state of Bahia. Unique among the Priodesmini, male C. albaserrata n. sp. possess greatly elongated pre-gonopodal tarsal claws and differ from the only congener, Cayenniola styliger (Jeekel, 1963), by a combination of gonopodal and somatic characters including classical troglomorphic traits such as a nearly unpigmented body and remarkably long antennae, legs, and tarsal claws. Cayenniola styliger is only known from the type locality in the Amazon rainforest of coastal French Guiana, suggesting that C. albaserrata n. sp. may represent a relictual species from the Caatinga Domain of Brazil. We provide ecological notes and evaluate the potential threats to the habitat of C. albaserrata n. sp., considering both the subterranean environment and the surrounding areas.

Nine new species of the Neotropical spider genus Epicratinus Jocqué & Baert, 2005 are described. Epicratinus includes now 25 species, all with male and female descriptions. An identification key for all species of the genus and maps for new species. The following nine new species are described: E. yoda sp. nov. from the state of Alagoas, Bahia, Paraíba and Pernambuco; E. temuerai sp. nov. from the state of Bahia and Mato Grosso; E. arlequina sp. nov. and E. maozinha sp. nov. from the state of Minas Gerais; E. leia sp. nov., E. baraka sp. nov. and E. smeagol sp. nov. from the state of Bahia; E. raiden sp. nov. from the state of Mato Grosso; E. luke sp. nov. from the state of Espírito Santo, all from Brazil.

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-Leito, 1942. Additionally, eight lycosid species are synonymized with Prolycosides aussereri: Schizocosa proletaria (Tullgren, 1905); Arctosa workmani (Strand, 1909); Hogna planithoracis (Mello-Leito, 1938); Hogna variolosa (Mello-Leito, 1941); Megarctosa melanostoma (Mello-Leito, 1941); Hippasosa huachoi (Mello-Leito, 1942); Pirata abalosi (Mello-Leito, 1942); and Pirata soukupi (Mello-Leito, 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.

This paper presents a taxonomic revision of the genus Tullgrenella Mello-Leito, 1941. Four new species are described: Tullgrenella aisenbergae Marta, sp. nov. (Brazil) (), T. legalissima Marta & Hagopin sp. nov. (Uruguay) (), T. galianoae Marta, sp. nov. (Brazil) () and T. sciosciae Marta & Bustamante sp. nov. (Brazil) (). The males of T. corrugata Galiano, 1981 and T. peniaflorensis Galiano, 1970, and the female of T. selenita Galiano, 1970 are described for the first time. An updated diagnosis for the genus is provided based on the detailed comparative morphological studies. In addition, we present a proposal and discussion about the species groups of Tullgrenella based on the putative synapomorphies as well as the updated distribution of the genus in South America.

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 genus Otoniela Brescovit, 1997 includes two species, the type species Otoniela adisi Brescovit, 1997, distributed in Peru and Brazil and O. quadrivittata (Simon, 1897), recorded in Venezuela and Argentina. Analyzing 127 individuals permited to expand the records of Otoniela adisi and to describe six additional species: O. lupercioi sp. nov. (), from Brazil, Argentina and Paraguay; O. chica sp. nov. (), O. duovizinhense sp. nov. (), and O. tigre sp. nov. (), from Brazil and Argentina; and O. aparecida n. sp () and O. negrinho sp. nov. (), known only from Brazil. As a result, a new emended diagnosis of the genus is presented. Additionally, complementary morphological data of Otoniela adisi are documented.

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).

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.

Tenedos O. Pickard-Cambridge, 1897, is the most diverse arrangement of Neotropical zodariids. The genus is composed by several species group, which only the barronus group is formally recognized. However, several groups remain uncharacterized despite being easily distinguishable by the distinctive sexual morphology. We formally proposed a second species group in Tenedos, the trilobatus group, including the known species Tenedos trilobatus Jocqu & Baert, 2002 from Colombia and T. figaro Jocqu & Baert, 2002 from Ecuador, whose type specimens are redescribed herein. Seven new species of the trilobatus group from Colombia are proposed based on both sexes: T. anchicaya sp. n. (), T. chiribiquete sp. n. (), T. cumbre sp. n. (), T. gabi sp. n. (), T. quimbaya sp. n. (), T. huila sp. n. (), T. valle sp. n. (). New data on the distribution range of Tenedos trilobatus in Colombia are included. We further provide distribution maps and an identification key for all species of the group. Morphological remarks of the new group and a comparison of it with the barronus group are included.

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, X 1 X 2 0; Coleosoma floridanum , Thymoites sp.1 and Thymoites sp.2 (Theridiidae), 2n♂ = 22, X 1 X 2 0; Naatlo sp. (Theridiosomatidae), 2n♂ = 30, X 1 X 2 0; Orthobula sp. (Trachelidae) 2n♂ = 21, X0; Falconina sp. (Corinnidae), 2n♂ = 28, X 1 X 2 0; Epicratinus sp. (Zodariidae) 2n♂ = 42, X 1 X 2 0. 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.

A new species, Strotarchus chamevazquezi sp. nov., is described based on both sexes from Department Francisco Morazán, Honduras. A detailed description, diagnosis, photographs, and distribution map of the new species are given. This is the first species of this genus recorded from Honduras.

The Atlantic Forest is known for its richness and diversity of species. Nonetheless, the diversity of millipedes in the biome is still poorly known. In this work, the distribution and the faunal composition of millipedes of the family Spirostreptidae Brandt, 1833 (order Spirostreptida) from the Atlantic Forest are provided. A total of 159 occurrence points were compiled, and 59 species in 17 genera were listed. Gymnostreptus Brölemann, 1902 was recovered as the richest genus in the Atlantic Forest with 14 species and one subspecies. The species Plusioporus setiger (Brölemann, 1902) presented the highest number of records, with 22 occurrence points in at least 20 municipalities. A total of 35 species were recorded from only one municipality. Considering all the threats on the biome, this paper is important for our understanding of the Brazilian millipede fauna and can be useful to determine places that require valuations for collecting efforts and conservation policies.

The new genus Tropicosa is proposed based on species of some controversial Neotropical genera of lycosids. These spiders present a longitudinal dark stripe over the sternum in both sexes, median apophysis sinuous, tegular lobe evidently sclerotized and the epigyne with median septum anteriorly expanded and with a parallel, triangular hood. We transfer Alopecosa moesta (Holmberg), Schizocosa chelifasciata (Mello-Leitão) and Lycosa thorelli (Keyserling) to Tropicosa gen. nov. and describe one new species, Tropicosa baguala sp. nov. Likewise, Arctosa bogotensis (Keyserling) is synonymized with Tropicosa thorelli (Keyserling) comb. nov., and Lycosa langei Mello-Leitão with T. chelifasciata (Mello-Leitão) comb. nov. based on examined types. All the four species proposed as members of Tropicosa gen. nov. have South American distribution.

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.

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.

The genus Tenedos O. Pickard-Cambridge, 1897 is the most diverse among Neotropical Zodariids. It is composed of 44 species, fourteen of which occur in Brazil, while in Colombia, the diversity of the genus is poorly known, with only seven species recorded for the country. Based on genital morphology, several species groups can be distinguished within the genus, but these have not been formally established. We propose the species group barronus to include 41 species, 34 of which are distributed in Colombia and the other seven exclusively occurring in: Brazil (one Amazonian species), Peru (three Andean species), and Venezuela (three Andean species). The previously proposed species Tenedos andes Jocqu Baert, 2002; T. peckorum Jocqu Baert, 2002; T. jocquei Quijano Galvis, 2018 and T. capote Jocqu Baert, 2002 are redescribed based on the type material and the females of the two former species are described for the first time. T. barronus (Chamberlin, 1925) and T. persulcatus Jocqu Baert, 2002 are reported for Colombia for the first time, the female of the latter is described. Twenty-eight new species are herein described, illustrated and their distributions are represented (species listed according to morphological affinities): T. ayo sp. n. (), T. calebi sp. n. (), T. caqueta sp. n. (), T. choco sp. n. (), T. cofan sp. n. (), T. dankittipakuli sp. n. (), T. eberhardi sp. n. (), T. neitai sp. n. (), T. tama sp. n. (), T. griswoldi sp. n. (), T. guacharos sp. n. (), T. henrardi sp. n. (), T. humboldti sp. n. (), T. carlosprietoi sp. n. (), T. narinensis sp. n. (), T. mesa sp. n. (), T. macagual sp. n. (), T. marquetones sp. n. (), T. medina sp. n. () , T. pensilvania sp. n. (), T. piedecuesta sp. n. (), T. quipile sp. n. (), T. santarosa sp. n. (), T. luzmarinae sp. n. (), T. tatama sp. n. (), T. ticuna sp. n. (), T. wayuu sp. n. () and T. yurayaco sp. n. (). We further provide new morphological data for some species included in the barronus group, and briefly discuss some aspects on morphological affinities and distribution between the species, based on a comparison with Tenedos type species, T. lautus O. Pickard-Cambridge, 1897. Distribution maps for all Colombian species, including new records for T. barronus and T. persulcatus, are also herein included. Additionally, an identification key for all species of the barronus group is provided.

Huriini Simon, 1901 currently consists of six genera and 17 species, distributed exclusively in South America. In this work, the huriine genus Guriurius Marta, Bustamante, Ruiz Rodrigues, gen. nov. is proposed with two new species herein described: Guriurius minuano Marta, Bustamante, Ruiz Rodrigues, sp. nov. (type species) and Guriurius nancyae Marta, Bustamante, Ruiz Rodrigues, sp. nov. The female of Atelurius segmentatus Simon, 1901 is described and illustrated for the first time. Scoturius dipterioides Perger Rubio, 2018 is transferred to Atelurius Simon, 1901 due to the morphological similarity of copulatory ducts of epigyne, and Hurius pisac Galiano, 1985 is transferred to Simonurius Galiano, 1988 due to the similarities in body shape and female genitalia. Simonurius campestratus (Simon, 1901) is synonymized with Simonurius quadratarius (Simon, 1901). The interpretation of genitalic characters in Huriini is discussed. In addition, we provide new distributional records for Admesturius bitaeniatus (Simon, 1901), Ad. mariaeugeniae Bustamante Scioscia, 2014, Ad. schajovskoyi Galiano, 1988, At. segmentatus Simon, 1901, Scoturius tigris Simon, 1901, Hurius aeneus (Mello-Leito, 1941), and Simonurius gladifer (Simon, 1901). Except for Urupuyu Ruiz Maddison, 2015, all huriine genera are rediagnosed in the new context of tribe and genus composition.

After recent sampling in the Southeast and Northeast of Brazil, six new species of Aphilodon are described and illustrated based on males and females. From the Atlantic Forest biome, Aphilodon foraminis n. sp., A. aiuruocae n. sp., A. acutus n. sp. and A. rectitibia n. sp. were registered in the state of Rio de Janeiro. Aphilodon cangaceiro n. sp. is the first record of Aphilodontinae for the state of Piau and was sampled in the Caatinga biome. Aphilodon bahianus n. sp. is the first species of Aphilodontinae known for the state of Bahia, being registered from the Atlantic Forest and in the Caatinga biomes. Additionally, some morphological characteristics of all known species of Aphilodon and their distributions are compared.

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.

Mecophilus carioca n. sp. is described based on males and females recently sampled in the Parque Nacional de Itatiaia, and is the first record of the genus from the state of Rio de Janeiro, Brazil. The specimens were analyzed in both light microscopy and scanning electron microscopy, and photos and schematic illustrations are provided. The known distribution of the three species of Mecophilus are presented in a map.

The diversity of endotherms and ectotherms may be differently affected by ambient temperature and net primary productivity (NPP). Additionally, little is known about how these drivers affect the diversity of guilds of different trophic levels. We assessed the relative role of temperature and NPP in multitrophic guilds of ectothermic (arthropods: ants, ground beetles, spiders, and harvestmen) and endothermic (large mammals) animals along a tropical elevational gradient. We sampled arthropods at eight elevation belts and large mammals at 14 elevation belts in Atlantic rainforest (ranging from 600 to 2450 m.a.s.l.) of Itatiaia National Park, Southeast Brazil. Overall arthropod species richness was more associated with temperature than overall large-mammal species richness, while the latter was more associated with NPP. When separated into trophic guilds, we found that the species richness associated with NPP increased across arthropod trophic levels from herbivores to predators. Conversely, although NPP influenced large-mammal herbivore species richness, its effects did not seem to accumulate across large-mammal trophic levels since the species richness of large-mammal omnivores was more associated with temperature and none of the variables we studied influenced large-mammal predators. We suggest that thermal physiological differences between ectotherms and endotherms are responsible for the way in which arthropods and large mammals interact with or are constrained by the environment. Furthermore, the inconsistency regarding the role of temperature and NPP on species richness across multitrophic guilds of ectotherms and endotherms could indicate that thermal physiological differences might also interfere with energy use and flux in the food web., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The species of Patrera Simon, 1903 from Brazilian Atlantic Forest biome are revised. With more than 2715 specimens examined, nine species were found and, of these, only one new species is described, Patrera teresopolis n. sp. from state of Rio de Janeiro. The other valid names were described by a single author: Patrera procera (Keyserling, 1891), P. longipes (Keyserling, 1891), P. virgata (Keyserling, 1891), P. cita (Keyserling, 1891), P. tensa (Keyserling, 1891), n. comb., P. opertanea (Keyserling, 1891), n. comb., P. concolor (Keyserling, 1891), n. comb. and P. recentissima (Keyserling, 1891), n. comb. (Later four here transferred from Teudis O. Pickard-Cambridge, 1896) and P. pellucida (Keyserling, 1891), n. comb. (here transferred from Sillus F.O. Pickard-Cambridge, 1900). The males of Patrera opertanea, P. pellucida and P. recentissima are described for the first time. The species Teudis itatiayae Mello-Leitão, 1915 and Sillus delicatus Mello-Leitão, 1922 are synonymized with P. longipes; Osoriella pallidoemanu Mello-Leitão, 1926 is synonymized with P. concolor. All species are described, illustrated and mapped. The known distribution of Patrera procera and P. longipes is expanded to Argentina and that of Patrera procera to Paraguay.

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 + X 1 X 2 X 3 X 4 , 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 + X 1 X 2 X 3 X 4 and metaphases II with n = 22 (18 telocentric autosomes + X 1 X 2 X 3 X 4 ), n = 21 (16 telocentric autosomes + a metacentric autosome + X 1 X 2 X 3 X 4 ), 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., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

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.

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.

The first two anophthalmic species of spiders of the genus Ochyrocera Simon, 1892, are described for caves located in the iron formation of Floresta Nacional (FLONA) de Carajás in southeastern Pará State, Brazil. The caves are located in the municipalities of Parauapebas and Canaã dos Carajás, in the eastern portion of the Amazon Forest domain. Ochyrocera ritxoco sp. nov. and O. ritxoo sp. nov. are described based on males and females. The species have similar body characteristics with the total absence of eyes and complete depigmentation, characteristics that indicate possible evolution in subterranean environments , and thus are classified as troglobites. Each species is associated with a single geomorphological unit (mountain range), with Ochyrocera ritxoco sp. nov. being restricted to caves of Serra Norte (North Mountain) and O. ritxoo sp. nov. to caves of Serra Sul (South Mountain). Both species were collected in aphotic zones of the caves. Small and tangled webs of O. ritxoco sp. nov. were observed under blocks of stone in the soil or in cracks of the walls., (Antonio D. Brescovit, Robson de A. Zampaulo, Igor Cizauskas.)

As large amounts of natural environments are lost due to urbanization, the role of remnant native vegetation in the preservation of biodiversity has become even more significant. Remnant native forest patches are essential refugia for flora and fauna and are crucial for the maintenance of ecosystem processes in urbanized landscapes. We evaluated the influence of landscape structure on ants and spiders associated with Atlantic Forest remnants in urban landscapes. We sampled 14 forest areas in the Metropolitan Region of Salvador and tested the effect of the landscapes' proportion of forest cover, mean landscape isolation, and mean landscape shape complexity on the taxonomic and functional richness and the community composition of both groups. The species collected were classified into functional groups based on behavioral attributes and environmental preferences. Overall, there were strong adverse effects of forest loss, decreased connectivity, and an increase in edge effects associated with the mean shape complexity of the forest remnants. However, the spiders responded to all three landscape structure characteristics whereas the ants only responded to the landscape mean shape complexity. Our findings indicate that the maintenance of urban forest habitats is essential for the conservation of biodiversity in the Metropolitan Region of Salvador and the preservation of ecological functions performed by species within the forest areas.

The knowledge on the diversity of the genus Patrera Simon in Colombia is widely expanded. P. auricoma (L. Koch, 1866) and P. armata (Chickering, 1940) are redescribed and their females are described for the first time and recorded from Cundinamarca and Meta departments, respectively. Aysha strandi (Caporiacco, 1947) is synonymized with P. armata. Three species groups in the genus Patrera are proposed to include the bulk of its species (fulvastra, florezi, and philipi). These groups are diagnosed based on sexual characters. Twenty-five new species are herein described, illustrated and mapped: P. anchicaya n. sp. (♂♀); P. barbacoas n. sp. (♂); P. borjai n. sp. (♂♀); P. danielae n. sp. (♂♀); P. dimar n. sp. (♂♀); P. perafani n. sp. (♂♀); P. platnicki n. sp. (♂); P. quillacinga n. sp. (♂♀), and P. ramirezi n. sp. (♂♀) into the fulvastra species group. P. bonaldoi n. sp. (♂♀); P. boteroi n. sp. (♂); P. carvalhoi n. sp. (♂♀); P. florezi n. sp. (♂♀); P. perijaensis n. sp. (♀); P. quimbaya n. sp. (♂♀); P. sampedroi n. sp. (♂); P. yukpa n. sp. (♂♀), and P. wiwa n. sp. (♂♀) in florezi species group. P. sutu n. sp. (♂); P. chucurui n. sp. (♂♀); P. dawkinsi n. sp. (♂); P. dentata n. sp. (♂); P. dracula n. sp. (♂); P. kuryi n. sp. (♂♀), and P. longitibialis n. sp. (♂) in philipi species group. We also briefly discuss some aspects of the species groups' genital morphology, based on a comparison with the type, P. fulvastra Simon. Additionally, distribution maps for all Colombian species including new records for P. armata (Chickering, 1940), P. auricoma (L. Koch, 1866) and P. suni Dupérré Tapia, 2016 from Cundinamarca, Meta and Nariño departments are also herein included.

The species of Syspira Simon from Hispaniola are revised and detailed documentation is provided for all known species from this island. Four new species (Syspira alayoni sp. n., S.  armasi sp. n., S.  barbacoa sp. n., and S.  bryantae sp. n.), and the unknown male of Syspira agujas Brescovit, Sánchez-Ruiz Bonaldo are described. New distribution records were found for three known species (S. agujas, S. cimitarra Brescovit, Sánchez-Ruiz Bonaldo and S.  medialuna Brescovit, Sánchez-Ruiz Bonaldo). The Hispaniolan endemic species Teminius monticola (Bryant, 1948) is transferred to Syspira based on the revision of its holotype. A key for Hispaniola Syspira species is provided. These species can be separated into two distinct groups based on features of the male palpal morphology and female genitalia: the cimitarra group including S. cimitarra, S. jimmyi Brescovit, Sánchez-Ruiz Bonaldo, S. alayoni and S. barbacoa sp. n., and the agujas group including S. agujas, S. medialuna, S. monticola comb. n., S. armasi sp. n. and S. bryantae sp. n.

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.

Brescovit (1993), in the revision of the genus Hibana, described H. talmina, based on males from Venezuela, Colombia, Guyana and northern Brazil. Subsequently, Brescovit Lise (1993) described its female, in an attempt to associate with the male, based on specimens collected in Dominica and Trinidad. Unfortunately, there was no justification for this mating. Recently Galvis et al. (2019) collected several couples of Hibana talmina in mangrove forests in some surrounding areas of Cartagena (Bolívar, Colombia), during a study of predation of crabs on these spiders. The detailed study of these couples showed that there was a wrong mating by Brescovit Lise (1993) and this is corrected here. The original distribution is updated, with the exclusion of Dominica. The females previously assigned to H. talmina are treated here as Hibana labonita sp. nov., which is diagnosed in relation to the other species of Hibana.

The species of the genus Centroctenus can be distinguished from other Ctenidae genera by the presence of a long tibiae and the absence of a retrolateral projection of the cymbium in the male palp, and by the presence of a rounded spermathecae in the female epigynum. The composition of this spider genus is herein expanded to eleven Neotropical species, with the description of six new species: Centroctenus dourados sp. n., C. claudia sp. n., C. chalkidisi sp. n., and C. varzea sp. n., from Brazil; and Centroctenus coloso sp. n. from Colombia and Centroctenus alinahui sp. n. from Ecuador. A map with the distribution of all known species in the genus is presented.

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.

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., Competing Interests: No authors have competing interests.

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.

The singular spider genus Nyetnops Platnick Lise is revised and three new species are described from Peru (Nyetnops naylienae n. sp.), Bolivia (Nyetnops lachonta n. sp.) and Brazil (Nyetnops buruti n. sp.). An updated diagnosis is proposed for the type species Nyetnops guarani Platnick Lise and new records from the Brazilian State of São Paulo are presented for this species. The Ecuadorian species Nyetnops juchuy Dupérré is elected as the type species of a new genus herein proposed (Nopsma n. gen.), which also harbors three other new species from Peru (Nopsma enriquei n. sp.), Colombia (Nopsma florencia n. sp.) and Nicaragua (Nopsma armandoi n. sp.).

Craspedisia cornuta (Keyserling, 1891), is redescribed on the basis of SEM data after more than fifty years after its last records. We also provide information on its natural history. SEM images for the proboscis, ventral plates of abdomen and male palp and epigynal plate are provided. Data on natural history using specimens collected in the Serra do Japi, from the state of São Paulo were analyzed and presented for the first time for this little-known species of Pholcommatinae theridiid spider.

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.

Aphilodontinae are a well distinct but poorly known group of soil centipedes (Chilopoda: Geophilomorpha: Geophilidae) inhabiting two disjunct areas in South America and South Africa respectively. A comprehensive revision of the Neotropical species is presented based on the examination of >150 specimens, the phylogenetic analysis of the entire subfamily based on 47 morphological characters, and the description of eight new species from Southeastern Brazil. The Aphilodontinae were confirmed a monophyletic clade within Geophilidae and closely related to Geoperingueyia, with which they share synapomorphic characters in the labrum, second maxillae and forcipules. Particular groups of clypeal setae, inconspicuous lateral parts of labrum and coalescent forcipular throchanteroprefemur and femur were recovered as synapomorphies of the Aphilodontinae. Four monophyletic genera are recognized within the subfamily Aphilodontinae Silvestri, 1909 (1908) (= Brasilophilidae Verhoeff, 1908; = Mecistaucheninae Verhoeff, 1925 n. syn.), three exclusively Neotropical and one exclusively South African. The Neotropical genera are: Aphilodon Silvestri, 1898 (= Mecistauchenus Brölemann, 1907 n. syn.; = Brasilophilus Verhoeff, 1908 n. syn.), with ten species (including A. caboclos n. sp., A. indespectus n. sp., A. meganae n. sp., A. pereirai n. sp. and A. silvestrii n. sp.), characterized by a small terminal spine on the ultimate legs, in both males and females; Mecophilus Silvestri, 1909, with two species (including M. tupiniquim n. sp.), characterized by elongated forcipular segment and first leg-bearing segment; Mairata n. gen., with two species (M. butantan n. sp. and M. itatiaiensis n. sp.), characterized by the partial reduction of the distal article of the second maxillary telopodite and a particular shape of ultimate legs, in both males and females. The South African genus, Philacroterium Attems, 1926, comprises eleven known species (including P. weberi (Silvestri, 1909) n. comb., P. caffrarium (Verhoeff, 1937) n. comb., P. porosum (Verhoeff, 1937) n. comb., P. brevipes (Verhoeff, 1938) n. comb., P. bidentatum (Lawrence, 1955) n. comb., P. longipes (Lawrence, 1955) n. comb., P. macronyx (Lawrence, 1955) n. comb., P. maritimum (Lawrence, 1963) n. comb., P. pauciporum (Lawrence, 1963) n. comb. and P. transvaalicum (Lawrence, 1963) n. comb.) and is characterized by vestigial lateral parts of the labrum and the complete suppression of the distal article of the telopodites of the second maxillae. Identification keys are provided for the Aphilodontinae genera and for the species of Aphilodon, Mecophilus and Mairata n. gen. The known occurrence of Aphilodon in Brazil is extended from the states of São Paulo and Mato Grosso to the states of Minas Gerais and Rio de Janeiro, that of Mecophilus from the state of Paraná to the state of São Paulo.

Phylogenetic niche conservatism (PNC) shapes the distribution of organisms by constraining lineages to particular climatic conditions. Conversely, if areas with similar climates are geographically isolated, diversification may also be limited by dispersal. Neotropical xeric habitats provide an ideal system to test the relative roles of climate and geography on diversification, as they occur in disjunct areas with similar biotas. Sicariinae sand spiders are intimately associated with these xeric environments, particularly seasonally dry tropical forests (SDTFs) and subtropical deserts/scrublands in Africa (Hexophthalma) and the Neotropics (Sicarius). We explore the role of PNC, geography and biome shifts in their evolution and timing of diversification. We estimated a time-calibrated, total-evidence phylogeny of Sicariinae, and used published distribution records to estimate climatic niche and biome occupancy. Topologies were used for estimating ancestral niches and biome shifts. We used variation partitioning methods to test the relative importance of climate and spatially autocorrelated factors in explaining the spatial variation in phylogenetic structure of Sicarius across the Neotropics. Neotropical Sicarius are ancient and split from their African sister-group around 90 (57-131) million years ago. Most speciation events took place in the Miocene. Sicariinae records can be separated in two groups corresponding to temperate/dry and tropical/seasonally dry climates. The ancestral climatic niche of Sicariinae are temperate/dry areas, with 2-3 shifts to tropical/seasonally dry areas in Sicarius. Similarly, ancestral biomes occupied by the group are temperate and dry (deserts, Mediterranean scrub, temperate grasslands), with 2-3 shifts to tropical, seasonally dry forests and grasslands. Most of the variation in phylogenetic structure is explained by long-distance dispersal limitation that is independent of the measured climatic conditions. Sicariinae have an ancient association to arid lands, suggesting that PNC prevented them from colonizing mesic habitats. However, niches are labile at a smaller scale, with several shifts from deserts to SDTFs. This suggests that PNC and long-distance dispersal limitation played major roles in confining lineages to isolated areas of SDTF/desert over evolutionary history, although shifts between xeric biomes occurred whenever geographical opportunities were presented., (Copyright © 2019 Elsevier Inc. All rights reserved.)