Cave-dwelling pholcid spiders (Araneae, Pholcidae): a review

Abstract

Pholcidae are ubiquitous spiders in tropical and subtropical caves around the globe, yet very little is known about cave-dwelling pholcids beyond what is provided in taxonomic descriptions and faunistic papers. This paper provides a review based on a literature survey and unpublished information, while pointing out potential biases and promising future projects. A total of 473 native (i.e. non-introduced) species of Pholcidae have been collected in about 1000 caves. The large majority of cave-dwelling pholcids are not troglomorphic; a list of 86 troglomorphic species is provided, including 21 eyeless species and 21 species with strongly reduced eyes. Most troglomorphic pholcids are representatives of only two genera: Anopsicus Chamberlin & Ivie, 1938 and Metagonia Simon, 1893. Mexico is by far the richest country in terms of troglomorphic pholcids, followed by several islands and mainland SE Asia. The apparent dominance of Mexico may partly be due to collectors' and taxonomists' biases. Most caves harbor only one pholcid species, but 91 caves harbor two and more species (up to five species). Most troglomorphic pholcids belong to two subfamilies (Modisiminae, Pholcinae), very few belong to Smeringopinae and Arteminae, none to Ninetinae. This is in agreement with the recent finding that within Pholcidae, microhabitat changes in general are concentrated in Modisiminae and Pholcinae.

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

“…Indeed, due to the general paucity of information on most subterranean spiders (e.g. Huber 2018, Mammola et al 2018, Cardoso 2012) and the lack of broad-scale databases about their distribution (Culver et al 2013, Mammola 2019), global-scale diversity patterns of subterranean spiders remain virtually undescribed (Mammola et al 2018a, Mammola and Isaia 2017). In an attempt to overcome this impediment, we created an international network of araneologists and cavers (that we called the "CAWEB" network; Mammola et al 2017) to compile the first continental-scale geo-referenced dataset of cave-dwelling and other subterranean spider communities (Mammola et al 2019b).…”

Metagonia esquincacanoi sp. nov.: el primer registro fósil de la familia Pholcidae (Arachnida: Araneae) en el ámbar de Chiapas, México.

“…Por otro lado, a pesar del gran número de especies actuales descritas, el conocimiento de la biología de las especies de Metagonia es insuficiente (Gertsch, 1986;Huber, 1997;Huber y Schütte, 2009). Algunas especies que componen el género son habitantes de hojas, sin embargo, algunas viven en cuevas (Gertsch, 1971(Gertsch, , 1977(Gertsch, , 1986Huber, 1998Huber, , 2018 y muy pocas son las que viven en los suelos, entre la hojarasca (Gertsch, 1986;Huber, 2005). De manera general, se reconocen 3 tipos de microhábitats en los fólcidos: a) de suelo, son aquellos que viven en la hojarasca y debajo de objetos en el suelo; b) de espacio, los que habitan en espacios protegidos, por ejemplo, entre los arbustos de árboles, rocas y troncos; c) habitantes de https://doi.org/10.…”

Exploring the Interplay Between Local and Regional Drivers of Distribution of a Subterranean Organism

“…Artema nephilit was also more abundant in warmer sectors of the cave (Figure 2), which is consistent with its apparent thermophily. Indeed, observations that were made during the cave survey, as well as the result of the SDM analysis (see below), indicates that A. nephilit prefers hot and relatively dry caves rather than cool and humid caves that are the preferred habitat of other cave-dwelling pholcid spiders found in the surveyed caves [31,33]. In areas where both hot and dry caves and cool and humid caves were present, A. nephilit inhabited the hot dry caves exclusively, while other pholcid spiders inhabited the cool humid caves [33].…”

“…The spider genus Artema Walckenaer, 1837 (Pholcidae) includes several troglophiles, and one recently discovered troglomorphic (i.e., with morphological adaptations to subterranean life) and possibly troglobiont species [31,32]. All these species have an overall Old World distribution that stretches from West and East Africa, to the Middle East and Central Asia.…”