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Southeast Asia is a hotspot of karst systems in the tropics and many relictual taxa have been documented in caves across the region. The ancient, relictual scorpion family Pseudochactidae Gromov 1998 has a disjunct distribution and includes two hypogean subfamilies from caves in the Khammouan-Phong Nha-Kẻ Bàng Karst in the northern Annamite (Trường Sơn) Mountains of Laos and Vietnam, and one epigean subfamily from Central Asia. A recent revision identified six species in the family; however, how these taxa dispersed and diversified into Southeast Asian cave systems has not been tested. In the present contribution, the phylogeny of Pseudochactidae is reconstructed using three mitochondrial and three nuclear markers and 140 morphological characters, divergence time and ancestral range estimation analyses are conducted, and the evolution of troglomorphic characters is investigated. Results confirm a previous hypothesis that Pseudochactidae originated in Eurasia, most likely near the Tajik block in the Carboniferous, supporting the ‘Out of Eurasia’ hypothesis and contradicting the ‘Eurogondwana’ and ‘Out of India’ hypotheses for the origin of Southeast Asian scorpions. Pseudochactidae dispersed across Southeast Asia after the collision of the Cimmerian continent and Indochina with Eurasia in the Late Jurassic. Colonization of Southeast Asian caves began in the Late Cretaceous and was completed by the Miocene. The onset of aridification in Southeast Asia during the Late Miocene resulted in the extinction of epigean Pseudochactidae, whereas hypogean members of the family likely survived within caves in the limestone massifs of the Annamite Mountains, supporting the ‘Climate Relict’ hypothesis.

 

Ricinulei Thorell, 1876 is an order of Arachnida currently represented in the New and Old Worlds by 103 living species. The order is also represented in the fossil record from the Carboniferous (ca. 305–319 Ma) and the Cretaceous (ca. 99 Ma) periods. In the present contribution, Hirsutisoma grimaldii sp. nov., a new extinct species of the suborder Primoricinulei Wunderlich, 2015, is described from a specimen preserved in Cretaceous Burmese amber. The specimen is a well-preserved adult male in which several taxonomically informative structures are visible, allowing the new species to be differentiated from Hirsutisoma bruckschi Wunderlich, 2017, the only other congener for which a male is known. This description raises the number of Cretaceous Ricinulei species to six. A comparative table documents morphological differences among the various species of this lineage. Hypotheses concerning the paleoecology and functional morphology of this species and, by extrapolation, other primoricinuleids, are presented. The evidence suggests that Primoricinulei were corticolous, scansorial predators. 

Whereas morphology remains a powerful tool for the diagnosis and description of short-tailed whip scorpions, or schizomids (Order Schizomida Petrunkevitch, 1945), especially when adults of both sexes are available, the systematics of some schizomid taxa is difficult to resolve due to a lack of characters in these morphologically conserved arachnids. Stenochrus portoricensis Chamberlin, 1922, defined on a single character of the female spermathecae, is the most widespread schizomid in the New World. Numerous records in the Neotropics, from the southern United States to Brazil, throughout the Caribbean, and further afield, including the Galapagos Islands and Europe, raise the question as to whether S. portoricensis is indeed a single widespread species or a complex of multiple species with conserved morphology? The present study uses a multilocus dataset and the broadest geographical sample currently available to address the phylogeography of S. portoricensis with molecular divergence dating and ancestral area reconstruction of all currently known species of Stenochrus Chamberlin, 1922. Analyses recovered S. portoricensis as paraphyletic. Two species previously synonymized are revalidated and transferred to Stenochrus. Population structure analyses recovered the remaining samples of S. portoricensis as a single monophyletic species with low genetic divergence and comprising two subclades. Ancestral area reconstruction suggests a Mesoamerican origin for Stenochrus, which contains a widespread species, recently introduced to multiple localities. Introductions to Europe and the Caribbean occurred from a single clade in the Yucatán Peninsula, Mexico, within which genetic divergence is minimal, confirming the hypothesis of multiple independent introductions with successful colonization facilitated by parthenogenetic reproduction.

 

The whip spider family Charinidae Quintero, 1986 is the most speciose and widely distributed in the arachnid order Amblypygi Thorell, 1883. It comprises three genera and 95 species distributed across all tropical continents and the eastern Mediterranean. Despite recent advances in the taxonomy of the family, a global revision of all its species, necessary to advance understanding of its systematics, biogeography and evolution, has never been conducted. In the present contribution, the family is revised in its entirety for the first time, including all previous names and 33 new species, 24 in the genus Charinus Simon, 1892: C. alagoanus sp. nov., C. apiaca sp. nov., C. carinae sp. nov., C. carioca sp. nov., C. carvalhoi sp. nov., C. cearensis sp. nov., C. diamantinus sp. nov., C. euclidesi sp. nov., C. goitaca sp. nov., C. guayaquil sp. nov., C. imperialis sp. nov., C. loko sp. nov., C. magalhaesi sp. nov., C. miskito sp. nov., C. mocoa sp. nov., C. monasticus sp. nov., C. palikur sp. nov., C. perquerens sp. nov., C. puri sp. nov., C. renneri sp. nov., C. sooretama sp. nov., C. souzai sp. nov., C. susuwa sp. nov., C. una sp. nov.; eight in the genus Sarax Simon, 1892: S. bilua sp. nov., S. dunni sp. nov., S. gravelyi sp. nov., S. indochinensis sp. nov., S. lembeh sp. nov., S. palau sp. nov., S. rahmadii sp. nov., S. tiomanensis sp. nov.; and one in the genus Weygoldtia Miranda et al., 2018: W. consonensis sp. nov. Taxonomic keys to the 132 species (excluding four nomina dubia) are presented and several taxonomic rearrangements implemented. Four subspecies are elevated to species level: Charinus cavernicolus Weygoldt, 2006, C. elegans Weygoldt, 2006, C. longipes Weygoldt, 2006, and Sarax bispinosus (Nair, 1934). Sarax batuensis Roewer, 1962 is removed from synonymy with Sarax buxtoni (Gravely, 1915) and S. buxtoni newly synonymized with Sarax rimosus (Simon, 1901). Stygophrynus moultoni Gravely, 1915 is transferred to Sarax, resulting in Sarax moultoni (Gravely, 1915) comb. nov. Ten species are transferred from Charinus to Sarax, resulting in new combinations: S. abbatei (Delle Cave, 1986) comb. nov., S. bengalensis (Gravely, 1911) comb. nov., S. dhofarensis (Weygoldt, Pohl & Polak, 2002) comb. nov., S. ioanniticus (Kritscher, 1959) comb. nov., S. israelensis (Miranda et al., 2016) comb. nov., S. omanensis (Delle Cave, Gardner & Weygoldt, 2009) comb. nov., S. pakistanus (Weygoldt, 2005) comb. nov., S. seychellarum (Kraepelin, 1898) comb. nov., S. socotranus (Weygoldt, Pohl & Polak, 2002) comb. nov. and S. stygochthobius (Weygoldt & Van Damme, 2004) comb. nov.