Spider Genus Research Articles

Two fancy spines and a collar: a taxonomic review of the myrmecomorphic spider genus Mazax O. Pickard-Cambridge, 1898 (Araneae: Corinnidae: Castianeirinae) in South America

The South American species of the myrmecomorphic spider genus Mazax O. Pickard-Cambridge, 1898 (Castianeirinae, Corinnidae) are revised for the first time, increasing the number of known species from South America from two to six and the number of species in the genus from seven to 11. Here, we reevaluate the identity of Apochinomma acanthaspis Simon, 1896, propose its transfer to Mazax, and consider M. akephaloi Perger & Pett, 2022 as a junior synonym of M. acanthaspis comb. nov. Additional documentation of M. ramirezi Rubio & Danişman, 2014 is provided. The species M. pax Reiskind, 1969 and M. spinosa (Simon, 1898) are recorded from South America for the first time. Three new species are proposed, all based on both sexes: Mazax mokana sp. nov. and M. leonidas sp. nov. from Colombia, and M. tembe sp. nov. from Brazil. Emended diagnoses of the genus and of all six known South American species, as well as a key to males and females for all 11 species in the genus, are provided.

Nine new spider species of Belisana Thorell, 1898 (Araneae, Pholcidae) from karst caves, with a list of species of the genus from Guizhou, southwestern China.

Species of the spider genus Belisana Thorell, 1898 exhibit high diversity in Guizhou, southwestern China. Previously, only eight species of Belisana were recorded in Guizhou. In this study, nine new species are described from karst caves: Belisanabijie Wang, S. Li & Yao, sp. nov., B.liupanshui Wang, S. Li & Yao, sp. nov., B.majiang Wang, S. Li & Yao, sp. nov., B.nayong Wang, S. Li & Yao, sp. nov., B.qixingguan Wang, S. Li & Yao, sp. nov., B.xiuwen Wang, S. Li & Yao, sp. nov., B.yongcong Wang, S. Li & Yao, sp. nov., B.zhouxi Wang, S. Li & Yao, sp. nov., and B.zunyi Wang, S. Li & Yao, sp. nov. Belisanazhangi Tong & Li, 2007 is reported from Guizhou for the first time. In addition, a list of all species of Belisana from Guizhou is provided.

Prey nutrient content is associated with the trophic interactions of spiders and their prey selection under field conditions

Consumers are thought to select food resources based on their nutritional content. While laboratory experiments have explored this, the nutritional dynamics of invertebrate predators have been scarcely studied in the field given various methodological constraints. The intersection of these nutritional dynamics with predator traits is also poorly characterised, leading to many gaps in our understanding of how different predators forage and feed in natural systems. Here, we integrate dietary metabarcoding with prey macronutrient (protein, lipid and carbohydrate) content and abundance to assess how nutrients and predator traits (sex, life stage and taxonomy) interactively drive prey preferences in the field, using spider–prey interactions as a model system. Different spider genera, sexes and life stages had nutritionally distinct diets. Our analyses demonstrated disproportionate foraging (selection and avoidance) for prey rich in different macronutrients, with the nature of these relationships differing between spider taxa, life stages and sexes. This may be explained by niche differentiation among spider groups, driven by biases toward prey rich in different nutrients, or nutrient‐specific foraging in which individual spiders vary their nutritional preferences to redress deficits, although further evidence is required to confirm this. This insight into the nutritional dynamics of generalist invertebrate predators extends our understanding beyond lab‐based behavioural assays and provides a novel framework for other complex real‐world systems.

Population Genomics of Adaptive Radiations: Exceptionally High Levels of Genetic Diversity and Recombination in an Endemic Spider From the Canary Islands.

The spider genus Dysdera has undergone a remarkable diversification in the oceanic archipelago of the Canary Islands, with ~60 endemic species having originated during the 20 million years since the origin of the archipelago. This evolutionary radiation has been accompanied by substantial dietary shifts, often characterised by phenotypic modifications encompassing morphological, metabolic and behavioural changes. Hence, these endemic spiders represent an excellent model for understanding the evolutionary drivers and to pinpoint the genomic determinants underlying adaptive radiations. Recently, we achieved the first chromosome-level genome assembly of one of the endemic species, D. silvatica, providing a high-quality reference sequence for evolutionary genomics studies. Here, we conducted a low coverage-based resequencing study of a natural population of D. silvatica from La Gomera island. Taking advantage of the new high-quality genome, we characterised genome-wide levels of nucleotide polymorphism, divergence and linkage disequilibrium, and inferred the demographic history of this population. We also performed comprehensive genome-wide scans for recent positive selection. Our findings uncovered exceptionally high levels of nucleotide diversity and recombination in this geographically restricted endemic species, indicative of large historical effective population sizes. We also identified several candidate genomic regions that are potentially under positive selection, highlighting relevant biological processes, such as vision and nitrogen extraction as potential adaptation targets. These processes may ultimately drive species diversification in this genus. This pioneering study of spiders that are endemic to an oceanic archipelago lays the groundwork for broader population genomics analyses aimed at understanding the genetic mechanisms driving adaptive radiation in island ecosystems.

Progress or burden? Formal description of every apparently new species available in collections is neither necessary nor useful.

A new species of the Sub-Saharan spider genus Quamtana Huber, 2003 is described that has been collected in garden centers in Poland and the UK. Its closest known relative is probably Q.lotzi Huber, 2003, known from Free State Province in South Africa. Working on the premise that placing species in time and space is the fundamental task of taxonomy, and acknowledging that we cannot provide biologically meaningful spatial information for this species, we prefer open nomenclature to make this species known to science without formally describing it, using the unique provisional name Quamtana sp. ZFMK Ar 24490 aff.lotzi. We argue that the judicious use of open nomenclature can serve to improve the quality of species lists, reducing the noise in large-scale analyses of biodiversity data. We expand this argument to 'fragmentary' species descriptions in general, such as single-sex descriptions in large genera with many male-only and female-only descriptions. Not every taxonomic act allowed by the Code is necessarily beneficial. Under certain conditions, the informal description of a putatively new species may serve science better than a formal description based on inadequate material or data.

Effects of climate change and species distribution modeling of Loxosceles (Araneae: Sicariidae) from Central Mexico

With 40 of the 149 described species, Mexico harbors the highest diversity of the spider genus Loxosceles. However,knowledge about these spiders’ distribution patterns in a climate change (CC) context is poorly known. In this study,the distributions of 4 species from Central Mexico, Loxosceles malintzi, L. misteca, L. tenochtitlan and L. zapoteca, were estimated and evaluated based on species distribution modeling (SDM) and the possible effects of CC. Two future scenarios were simulated (years 2050 and 2080) to show possible increases or reductions in species distributions. The most important variables that influence the distribution of the species were: isothermality, seasonality of temperature, and precipitation. In the CC scenarios, some species showed a possible increase, specifically, Loxosceles malintzi with an increase in its distribution of 79% by 2050 and 66% by 2080, whereas L. misteca was projected to increase its distribution by 28% for 2050 and 38% for 2080. However, a decrease in the distribution of L. tenochtitlan by 51% for 2050 and 38% for 2080 was projected, as well as a 45% decrease by 2050 and a 40% decrease by 2080 for L. zapoteca.

A new genus of lyrate curtain-web spiders (Araneae: Mygalomorphae: Dipluridae) from southeastern Brazil, with two new species and revalidation of a formerly described species

A new genus of lyrate curtain-web spiders (Araneae: Mygalomorphae: Dipluridae) from southeastern Brazil, with two new species and revalidation of a formerly described species

A new species of the spider genus Khorata Huber, 2005 (Araneae, Pholcidae), with a list of Khorata species from Vietnam.

The genus Khorata Huber, 2005 contains 51 species. It is distributed in the Indo-Malayan Region. Nine species have been recorded from Vietnam. Khorataninhbinh sp. nov. is described as a new species from Vietnam. In addition, a list of all Khorata species from Vietnam is also provided.

Unraveling female mate choice in Schizocosa mccooki: The interplay of male mass and vibratory courtship

AbstractSexual selection is an important evolutionary force and despite extensive research, understanding mate choice on naturally occurring trait variation remains an intriguing area of study. The correlation between mass, a trait associated with courter viability and common target for mate choice, and signals is particularly noteworthy. This study focuses on Schizocosa mccooki, the largest member of a wolf spider genus renowned for its diverse complex male courtship. Our objective was to understand the relationship of male mass and other courtship signals on female choice within this species. We conducted lab experiments involving random pairings of field caught males and females, recording vibratory courtship and its outcomes. Our findings revealed that S. mccooki courtship consisted of vibratory signals with two major components, thumps and raps. Male mass, overall courtship vigor, and thump duration were found to predict mating success. Interestingly, we found no correlation between temporal traits and mass suggesting independent information and an absence of trade‐offs between mass, courtship vigor, and signal component rates/durations. Instead, we found that heavier males tend to produce thumps with lower frequencies. The finding that male mass predicts mating success contrasts with patterns observed in other species in this well‐studied genus. By uncovering the mate choice patterns of S. mccooki, this study underscores the importance of comparative studies to understand the ways in which sexual selection drives diversification, even among closely related taxa.

New distribution records of two jumping spiders of the genus Stenaelurillus Simon, 1886 (Araneae: Salticidae) from Gujarat, India

The jumping spider genus Stenaelurillus Simon, 1886, belonging to the tribe Aelurillini (Maddison, 2015), is widely distributed and currently comprises 59 known species (World Spider Catalog 2024). Through recent investigations, we have identified two additional species of the genus Stenaelurillus that have not been documented in Gujarat state before. This paper therefore presents the new records and documentation of S. marusiki Logunov, 2001, and S. vyaghri Sanap, Joglekar & Caleb, 2022, marking their first appearances in Gujarat, India.

A new spider species of Belisana Thorell, 1898 (Araneae, Pholcidae) from Guizhou Province, south-western China.

China exhibits remarkable diversity of the spider genus Belisana Thorell, 1898, with 62 species recorded to date. However, the largest number of Belisana species was found in Yunnan Province (23 ssp.), while only seven species were found in Guizhou Province. In this paper, Belisanawangchengi sp. nov. as a new species is described from Guizhou Province, China.

Taxonomic and distributional notes on four recently described Stenaelurillus species from India (Araneae: Salticidae)

Notes on four species of the jumping spider genus Stenaelurillus Simon, 1886 from India are presented. Stenaelurillus jagannathae Das, Malik & Vidhel, 2015 syn. nov. is recognized as a junior synonym of S. arambagensis (B. Biswas & K. Biswas, 1992). The mismatched sexes of S. tettu Logunov, 2020 and S. indicus Logunov, 2020 are corrected. The females originally described as S. tettu are recognized as belonging to S. indicus and vice versa. Supplementary morphometric details of S. tettu are provided and new distribution records and illustrations for S. tettu and S. albus Sebastian, Sankaran, Malamel & Joseph, 2015 are presented.

On the Mexican trapdoor spiders: description of a new species of the spider genus Eucteniza Ausserer (Araneae, Mygalomorphae, Euctenizidae) from the western coast of Mexico

The trapdoor spider genus Eucteniza Ausserer, 1875 is distributed in North America, with most diversity in Mexico. In this work, a new species is described from the Chamela-Cuixmala Biosphere Reserve, Jalisco, Mexico: Eucteniza cuixmala sp. nov., was collected from a dry tropical deciduous forest in the western coast of Mexico. The species is described only from the male holotype. Of the 14 species of Eucteniza described so far, eight have been described based only on the male holotype. The description of this new species increases the diversity of the genus to 15 known species, 14 of which are found in Mexico, two in the USA, and one in both countries: E. relata (O. Pickard-Cambridge, 1895). In addition, we provide an amended taxonomic identification key for males of the genus.

Two new species of the comb-footed spider genus Lasaeola Simon, 1881 (Araneae: Theridiidae) from China

Two new species of the spider genus Lasaeola Simon, 1881 are described from China based on both sexes: Lasaeola pinna n. sp., and Lasaeola tengchongensis n. sp. Distribution data, detailed morphological characteristics, and illustrations of body and genital organs are presented.

A new species of the spider genus Mexentypesa Raven (Araneae: Nemesiidae) from Hidalgo, Mexico and taxonomic comments on M. chiapas Raven

A new species of the enigmatic spider genus Mexentypesa (Raven, 1987) from a cloud forest in Hidalgo state, Mexico is described: M. hidalguensis sp. nov. The description of the species is based on both male and female adult specimens. This discovery increases the diversity of the genus to two species: Mexentypesa chiapas (Raven, 1987) and the new species described herein. Additionally, Aptostichus sabinae syn. nov. (=M. chiapas), which was previously described as a different species, is formally synonymized.

On three species of the genus Habrocestum Simon, 1876 (Araneae: Salticidae: Hasariini) from India

Two new species of the ground-dwelling jumping spider genus Habrocestum Simon, 1876 from the wet evergreen forests of the southern Western Ghats, India are described: H. benjamin sp. nov. (♂♀) and H. swaminathan sp. nov. (♂♀). Furthermore, H. emanasakgrensis Kadam & Tripathi, 2023 is synonymized with Chinattus validus (Xie, Peng & Kim, 1993) syn. nov.. Diagnoses, digital illustrations, morphological descriptions, natural history notes and discussion are provided.

A phylogenomic approach to a taxonomic revision: a combination, new synonymies, and a description of two new species within the camel spider genus Chanbria Muma, 1951 (Solifugae: Eremobatidae)

Abstract This study summarizes the taxonomic treatment of the camel spider genus Chanbria Muma, 1951. Taking an integrative taxonomic approach incorporating phylogenomic, morphological, and geographical information, the genus is herein revised. Of the four species currently placed in the genus, two are retained: Chanbria regalis Muma, 1951 and Chanbria serpentinus Muma, 1951. Eremochelis plicatus (Muma, 1962) is transferred to this genus because it is consistently recovered in a clade with Chanbria based on several phylogenetic analyses using hundreds of loci recovered from ultraconserved element data. In this study, we re-analyse previously acquired genomic data to assess former species hypotheses and identify new morphological synapomorphies that support the monophyly of Chanbria. The genetic data support the synonymization of Chanbria rectus Muma, 1962 syn. nov. with C. regalis. Furthermore, we synonymize Chanbria tehachapianus Muma, 1962 syn. nov. with C. regalis because C. tehachapianus was erected based on limited morphological information and lack of geographical separation between other populations of C. regalis. Two new species, Chanbria brookharti sp. nov. and Chanbria mapemes sp. nov., are described. This brings the total number of species of Chanbria described to five recognized species: C. regalis, C. serpentinus, C. plicatus com. nov., C. brookharti sp. nov., and C. mapemes sp. nov.

A new species of the spiny trapdoor spider genus Blakistonia (Mygalomorphae: Idiopidae) from Kangaroo Island, South Australia

The first species of the Australian spiny trapdoor spider genus Blakistonia Hogg, 1902 to be recorded from Kangaroo Island, South Australia, is described from both males and females, bringing the number of described species of Blakistonia to 21. Blakistonia rooinsula sp. nov. has been recorded from coastal habitats and nearby locations, across a number of sites on Kangaroo Island.

A new species and new records of the spider genus Dubiaranea (Araneae, Linyphiidae) from southern Brazil and Uruguay, with an analysis of the potential distribution of the species

Dubiaranea magatama Cajade, Hagopián & Rodrigues n. sp. is described from Uruguay, and southern Brazil based on males and females from several types of native forests, and a potential distribution for this species is modeled. The predicted model for this species indicates a Pampean province and southern Atlantic Forest biome distribution. Three variables contributed significantly to the model with positive influence: the spatial component, the proximity to large rivers, and the tree cover. Also, we provide new records of Dubiaranea difficilis (Mello-Leitão 1944) for Uruguay and a model of its potential distribution was performed. It showed that tree cover, the proximity to large rivers, the spatial component and precipitation/evapotranspiration constraints were recovered for the model with positive influence, expanding the potential distribution area previously proposed.

Two new species and one new record of Ischnothyreus Simon, 1893 (Araneae, Oonopidae) from China.

Ischnothyreus Simon, 1893 is a large genus of oonopid spiders that currently contains 126 species, amongst which, 28 have been recorded in China. Two new Ischnothyreus species, Ischnothyreusdaheling Tong & Zhang, sp. nov. and Ischnothyreuslongyang Tong & Zhang, sp. nov., are described, based on specimens collected from Yunnan Province and Ischnothyreusvelox Jackson, 1908 is recorded in China for the first time, based on material collected from Guangxi Province. All three species are illustrated.