High endemism at cave entrances: a case study of spiders of the genus Uthina

Diversity of Pholcus Spiders (Araneae: Pholcidae) in China's Lüliang Mountains: An Integrated Morphological and Molecular Approach

Spiders of the genus Pholcus were collected for the first time during an expedition to the Lüliang Mountains in Shanxi Province, North China. Phylogenetic analyses of DNA sequence data from COI, H3, wnt, and 28S genes allowed us to group them into nine well-supported clades. We used morphology and four methods of molecular species delimitation, namely Automatic Barcode Gap Discovery (ABGD), the Generalized Mixed Yule Coalescent (GMYC), Bayesian Poisson Tree Processes (bPTP), and Bayesian Phylogenetics and Phylogeography (BPP), to investigate species boundaries. These integrative taxonomic analyses identified the nine clades as nine distinct species, comprising Pholcus luya Peng & Zhang, 2013 and eight other species new to science: Pholcus jiaocheng sp. nov., Pholcus linfen sp. nov., Pholcus lishi sp. nov., Pholcus luliang sp. nov., Pholcus wenshui sp. nov., Pholcus xiangfen sp. nov., Pholcus xuanzhong sp. nov., and Pholcus zhongyang sp. nov. The species occur in geographic proximity and show many morphological similarities. All of them belong to the P. phungiformes species group. The records from the Lüliang Mountains represent the westernmost distribution limit of this species group.

Taxonomic notes on eleven species of the subfamily Cteninae (Araneae, Ctenidae) from Asia

Background

The spider family Ctenidae Keyserling, 1877 has a worldwide distribution with 584 species belonging to 49 genera. Amongst these, 141 species are from Asia, including 130 species assigned to Cteninae Keyserling, 1877.

New information

Nine new species belonging to three genera of Cteninae are reported from Asia: Amauropelmakrabi sp. n. (female; Krabi, Thailand), Am.phangnga sp. n. (male; Phang Nga, Thailand), Am.saraburi sp. n. (male and female; Saraburi, Thailand); Anahitamedog sp. n. (male and female; Tibet, China); Bowieninhbinh sp. n. (male; Ninh Binh, Vietnam) and B.vinhphuc sp. n. (male and female; Vinh Phuc, Vietnam) from the robustus-species group; B.borneo sp. n. (male; Sabah, Malaysia) from the chinagirl-species group; B.engkilili sp. n. (female; Engkilili, Malaysia); B.sabah sp. n. (male and female; Sabah, Malaysia) from the scarymonsters-species group. The male of An.popa Jäger & Minn, 2015 and the female of B.fascination Jäger, 2022 (robustus-species group) are described for the first time. B.fascination Jäger, 2022 is reported from China for the first time. In addition, the DNA barcodes of all the species in this study were obtained, except for B.vinhphuc sp. n.

Tip of the iceberg: species diversity of Pholcus spiders (Araneae, Pholcidae) in the Changbai Mountains, Northeast China

Despite 250 years of taxonomic classification and over 1.2 million species already catalogued, known species diversity is only a small part of true species diversity on Earth, and thus, the known species are only the tip of iceberg. Here, we investigated the genus Pholcus Walckenaer, 1805 of the family Pholcidae C. L. Koch, 1850 in the Changbai Mountains, Northeast China, which provides an excellent case of high species diversity. Previously, only 14 endemic Pholcus spiders, all belonging to the P. phungiformes species group, and two introduced species P. manueli Gertsch, 1937 and P. zichyi Kulczyński, 1901 from the P. crypticolens species group, have been recorded from this area. Our study confirmed 11 new species of the P. phungiformes species group based on morphology and three methods of molecular species delimitation: P. gaizhou Yao & Li, sp. nov., P. guanshui Yao & Li, sp. nov., P. jiguanshan Yao & Li, sp. nov., P. longxigu Yao & Li, sp. nov., P. luoquanbei Yao & Li, sp. nov., P. shenshi Yao & Li, sp. nov., P. tianmenshan Yao & Li, sp. nov., P. wangjiang Yao & Li, sp. nov., P. xingqi Yao & Li, sp. nov., P. yaoshan Yao & Li, sp. nov., and P. yuhuangshan Yao & Li, sp. nov. This study brings the fauna of the P. phungiformes species group from the Changbai Mountains to 25 species, approximately two times more than previously known, which could indicate that species diversity in the area is underestimated for all arthropod fauna.

Notes on two closely related spider species of the Pholcus phungiformes species group (Araneae, Pholcidae) from Beijing, China

The Pholcus phungiformes species group is highly diverse and currently contains 53 species. In this study, Pholcus tongyaoi Wang & Yao, sp. nov. (male, female) from Huairou District, Beijing, China is described while similar congener Pholcus lexuancanhi Yao, Pham & Li, 2012 from neighboring Haidian District (type locality) is redescribed; the female of P. lexuancanhi is described for the first time. In addition, the DNA barcode COI for the two species was obtained to estimate p-distance.

Continental data on cave-dwelling spider communities across Europe (Arachnida: Araneae)

BACKGROUND

Spiders (Arachnida: Araneae) are widespread in subterranean ecosystems worldwide and represent an important component of subterranean trophic webs. Yet, global-scale diversity patterns of subterranean spiders are still mostly unknown. In the frame of the CAWEB project, a European joint network of cave arachnologists, we collected data on cave-dwelling spider communities across Europe in order to explore their continental diversity patterns. Two main datasets were compiled: one listing all subterranean spider species recorded in numerous subterranean localities across Europe and another with high resolution data about the subterranean habitat in which they were collected. From these two datasets, we further generated a third dataset with individual geo-referenced occurrence records for all these species.

NEW INFORMATION

Data from 475 geo-referenced subterranean localities (caves, mines and other artificial subterranean sites, interstitial habitats) are herein made available. For each subterranean locality, information about the composition of the spider community is provided, along with local geomorphological and habitat features. Altogether, these communities account for > 300 unique taxonomic entities and 2,091 unique geo-referenced occurrence records, that are made available via the Global Biodiversity Information Facility (GBIF) (Mammola and Cardoso 2019). This dataset is unique in that it covers both a large geographic extent (from 35° south to 67° north) and contains high-resolution local data on geomorphological and habitat features. Given that this kind of high-resolution data are rarely associated with broad-scale datasets used in macroecology, this dataset has high potential for helping researchers in tackling a range of biogeographical and macroecological questions, not necessarily uniquely related to arachnology or subterranean biology.

New species reveal unexpected interspecific microhabitat diversity in the genus Uthina Simon, 1893 (Araneae : Pholcidae)

Representatives of the Southeast Asian pholcid spider genus Uthina Simon, 1893 have been thought to be very homogeneous in their ecology and morphology. The 14 previously known species all inhabit near-ground microhabitats and cave entrances, and range from pale to dark brown in colour. Even their genitalia are partly very similar, with some species pairs being barely distinguishable based on morphological characters. Here we describe three new species from Bali, Java and Sulawesi that represent three further microhabitats and demonstrate considerable ecological and morphological diversity within the genus: U. maya, sp. nov. from Bali is a large dark species on tree trunks; U. hylobatea, sp. nov. from Bali and eastern Java is a pale leaf-dwelling species that exhibits colour dimorphism; and U. mimpi, sp. nov. is a pale troglomorphic species collected in the aphotic zones of two South Sulawesi caves. In addition, we present new data for five previously described species, including ultrastructure, natural history, new records, taxonomic notes and a description of the previously unknown female of Uthina khaosokensis Yao, Li & Jäger, 2014. Molecular data suggest that all previously described species are very closely related to each other (constituting the monophyletic luzonica-group), and that the three new species represent separate clades within the genus. However, the basal trichotomy could not be resolved: U. maya + (U. hylobatea + U. mimpi) + luzonica-group.

Day–night and seasonal variations of a subterranean invertebrate community in the twilight zone

Being characterized by the absence of light and a reduced environmental cyclicity, the subterranean domain is generally regarded as temporally stable. Yet, in the proximity of cave entrances (twilight zones), patterns of sunlight and darkness can be detected within the 24-hour day–night cycle. In parallel, changes in the abiotic and biotic conditions are expected; however, these patterns have been rarely explored in animal communities dwelling in the twilight zone. We performed a biological investigation in a small abandoned mine in the Western Alps, monitoring it once per season, both during the day and at night. At each survey, we collected data on the spatial distribution of the resident species, their activity patterns, and the main microclimatic parameters. We observed significant daily variations in the environmental conditions during winter and spring, namely higher temperature, relative humidity and availability of trophic resources at night. In conjunction with these disparate nocturnal conditions, the abundance of troglophile species was also higher, as well as the activity patterns of one of the most frequent species inhabiting the entrance area – the orb-weaver spiderMetamenardi. We further documented temporal changes in the composition of the parietal community, due to species using the mine as a diurnal, nocturnal or overwintering shelter. Overall, our results suggest that the communities of the twilight zone are not temporally stable and we highlight the importance of taking into account not only their seasonal, but also their daily variations.

Spiders in caves

World experts of different disciplines, from molecular biology to macro-ecology, recognize the value of cave ecosystems as ideal ecological and evolutionary laboratories. Among other subterranean taxa, spiders stand out as intriguing model organisms for their ecological role of top predators, their unique adaptations to the hypogean medium and their sensitivity to anthropogenic disturbance. As the description of the first eyeless spider (Stalita taenaria), an array of papers on subterranean spider biology, ecology and evolution has been published, but a comprehensive review on these topics is still lacking. We provide a general overview of the spider families recorded in hypogean habitats worldwide, we review the different adaptations of hypogean spiders to subterranean life, and we summarize the information gathered so far about their origin, population structure, ecology and conservation status. Finally, we point out the limits of the knowledge we currently have regarding hypogean spiders, aiming to stimulate future research.