Notes on the identity of the orb-weaver spider Araneus nox Simon, 1877 (Araneae: Araneidae) from India, including its transfer to Eriovixia Archer, 1951 and one new synonymy

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  Notes on the identity of the orb-weaver spider Araneus nox Simon, 1877 (Araneae: Araneidae) from India, including its transfer to Eriovixia Archer, 1951 and one new synonymy The orb-weaver genus Araneus Clerck, 1757 has historically served as a heterogeneous assemblage for numerous araneid spiders lacking clear generic placement, and several Asian species formerly assigned to Araneus have subsequently been transferred to more narrowly defined genera. One species that still needs further investigation on its true identity is Araneus nox (Simon, 1877), originally described as Epeira nox Simon, 1877 from Basilan Island, Philippines, and later transferred to Araneus by Simon (1905). In the same year as the description of Epeira nox, Thorell (1877) described Epeira pilula from the Moluccas (Indonesia), which was subsequently synonymised under Epeira nox by Simon (1880). Despite its broad Oriental distribution, the taxonomic identity and generic placement of A. nox have remained insuff...

Tempo and mode of diversification of the red devil spiders (Araneae: Dysderidae) of the Canary Islands

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Tempo and mode of diversification of the red devil spiders (Araneae: Dysderidae) of the Canary Islands

   Abstract

The study of adaptive radiations has shed light on our current understanding of evolution. However, previous studies examining the mode in which species diversified, how diversification rates varied, and how ecological specialization affected these processes have found few different results across different taxa and geographic and ecological systems, showing how complex this process is. To gain a more complete picture of how species evolve, additional model systems that encompass alternative ecological requirements are needed. Here, we present the results of a study aimed to unravel the diversification mode and evolutionary drivers of the spider genus Dysdera, the red devil spiders, endemic to the Canary Islands. These species exhibit remarkable phenotypic variability in their mouthparts, which has been related to different levels of specialization in the predation of isopods. We explored patterns of linage diversification and assessed the role of trophic specialization as a driver of species diversification. Additionally, we used climatic variables, occurrence data and morphological information to unravel the underlying mode of speciation by means of joint species distribution models and age-range correlation methods. Our results reveal that red devil spiders underwent an early burst of diversification, followed by a slowdown of diversification rates, which is a hallmark of adaptive radiation. We also found evidence that the trophic morphology shaped diversification, with specialist species exhibiting higher rates of diversification. Finally, our analyses suggest that speciation occurred mostly in allopatry, with subsequent secondary sympatry following range expansion.

Tempo and mode of diversification of the red devil spiders (Araneae: Dysderidae) of the Canary Islands
Adria Bellvert, Laura Pollock, Antigoni Kaliontzopoulou, Miquel A. Arnedo
bioRxiv 2024.07.09.601672; doi: https://doi.org/10.1101/2024.07.09.601672