New species of Paktongius and convergent evolution of the gonyleptoid-like habitus in Southeast Asian Assamiidae (Opiliones: Laniatores)

The armored harvestman family Assamiidae (Arachnida: Opiliones: Laniatores) is widely distributed throughout the Old World tropics, specifically throughout tropical Asia and Central Africa. However, the systematics and intrafamilial relationships of the group remain poorly understood. This can be largely attributed to the complicated taxonomic history of the group, which is exemplified by poorly supported subfamily classifications and the prevalence of monotypic genera. Here, we describe four new species of the formerly monotypic genus Paktongius Suzuki, 1969, using specimens collected from Laos, Thailand, and West Malaysia, suggesting a degree of microendemism within the group, which underscores the need for greater sampling of the southeast Asian arachnofauna. Recent phylogenetic analysis has also suggested that Mysorea thaiensis Suzuki, 1985 nests within a clade composed of Paktongius distinctus Suzuki, 1969 and the species described herein (P. suzukii sp. nov., P. spiculosus sp. nov., P. paritensis sp. nov., P. furculus sp. nov.). We therefore transfer Mysorea thaiensis to Paktongius (P. thaiensis comb. nov.). We also comment on the unique morphology of this highly derived group of harvestmen, which appears to suggest convergent evolution of the gonyleptoid-like morphology, complete with the characteristic exaggerated leg four coxae and laterally expanded scutum.

In the land of the blind: Exceptional subterranean speciation of cryptic troglobitic spiders of the genus Tegenaria (Araneae: Agelenidae) in Israel

Caves have long been recognized as a window into the mechanisms of diversification and convergent evolution, due to the unique conditions of isolation and life in the dark. These lead to adaptations and reduce dispersal and gene flow, resulting in high levels of speciation and endemism. The Israeli cave arachnofauna remains poorly known, but likely represents a rich assemblage. In a recent survey, we found troglophilic funnel-web spiders of the genus Tegenaria in 26 caves, present mostly at the cave entrance ecological zone. In addition, we identified at least 14 caves inhabited by troglobitic Tegenaria, which are present mostly in the twilight and dark ecological zones. Ten of the caves, located in the north and center of Israel, are inhabited by both troglophilic and troglobitic Tegenaria. These spiders bear superficial phenotypic similarities but differ in the levels of eye reduction and pigmentation. To test whether these taxa constitute separate species, as well as understand their relationships to epigean counterparts, we conducted a broad geographic sampling of cave-dwelling Tegenaria in Israel and Palestine, using morphological and molecular evidence. Counterintuitively, our results show that the troglobitic Tegenaria we studied are distantly related to the troglophilic Tegenaria found at each of the cave entrances we sampled. Moreover, seven new troglobitic species can be identified based on genetic differences, eye reduction level, and features of the female and male genitalia. Our COI analysis suggest that the Israeli troglobitic Tegenaria species are more closely related to eastern-Mediterranean congeners than to the local sympatric troglophile Tegenaria species, suggesting a complex biogeographic history.

The Phylogeny and Evolution of the Flashiest of the Armored Harvestmen (Arachnida: Opiliones)

Gonyleptoidea, largely restricted to the Neotropics, constitutes the most diverse superfamily of Opiliones and includes the largest and flashiest representatives of this arachnid order. However, the relationships among its main lineages (families and subfamilies) and the timing of their origin are not sufficiently understood to explain how this tropical clade has been able to colonize the temperate zone. Here, we used transcriptomics and divergence time dating to investigate the phylogeny of Gonyleptoidea. Our results support the monophyly of Gonyleptoidea and all of its families with more than one species represented. Resolution within Gonyleptidae s.s. is achieved for many clades, but some subfamilies are not monophyletic (Gonyleptinae, Mitobatinae, and Pachylinae), requiring taxonomic revision. Our data show evidence for one colonization of today's temperate zone early in the history of Gonyleptidae, during the Paleogene, at a time when the Neotropical area extended poleward into regions now considered temperate. This provides a possible mechanism for the colonization of the extratropics by a tropical group following the Paleocene-Eocene Thermal Maximum, explaining how latitudinal diversity gradients can be established. Taxonomic acts: Ampycidae Kury 2003 is newly ranked as family; Neosadocus Mello-Leitão is transferred to Progonyleptoidellinae (new subfamilial assignment). [Arachnids; biogeography; phylogenomics; transcriptomics.].

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

Caves are excellent model systems to study the effects of abiotic factors on species distributions due to their selective conditions. Different ecological factors have been shown to affect species distribution depending on the scale of analysis, whether regional or local. The interplay between local and regional factors in explaining the spatial distribution of cave-dwelling organisms is poorly understood. Using the troglophilic subterranean spider Artema nephilit (Araneae: Pholcidae) as a model organism, we investigated whether similar environmental predictors drive the species distribution at these two spatial scales. At the local scale, we monitored the abundance of the spiders and measured relevant environmental features in 33 caves along the Jordan Rift Valley. We then extended the analysis to a regional scale, investigating the drivers of the distribution using species distribution models. We found that similar ecological factors determined the distribution at both local and regional scales for A. nephilit. At a local scale, the species was found to preferentially occupy the outermost, illuminated, and warmer sectors of caves. Similarly, mean annual temperature, annual temperature range, and solar radiation were the most important drivers of its regional distribution. By investigating these two spatial scales simultaneously, we showed that it was possible to achieve an in-depth understanding of the environmental conditions that governs subterranean species distribution.