A chelicera-bearing arthropod reveals the Cambrian origin of chelicerates

Posted by
  A chelicera-bearing arthropod reveals the Cambrian origin of chelicerates Abstract Chelicerata is a megadiverse (over 120,000 species) arthropod clade that includes familiar taxa of profound ecological and economic importance, such as scorpions, spiders and mites 1 . Extant chelicerates share a unique anatomical character, the chelicerae—feeding first appendages terminated by a simple pincer-like chela 2 . The fossil record of these primarily predatory animals spans almost 500 million years 3 , suggesting a likely yet undocumented origin during the Cambrian Explosion. Artiopods 4 , 5 , 6 , megacheirans 4 , 7 , 8 , 9 , habeliids 10 , 11 , 12 , 13  and mollisoniids 14 , 15  have been considered Cambrian stem- or crown-group chelicerates, but they all lack unequivocal chelicerae, leaving the emergence of chelicerae-bearing arthropods unclear. Here we describe  Megachelicerax cousteaui  gen. et sp. nov., a large soft-bodied arthropod from the middle Cambrian of Ut...

A review of the spider genus Sinoalaria (Araneae, Theridiosomatidae), with the descriptions of four new species and two new combinations

Posted by


A review of the spider genus Sinoalaria (Araneae, Theridiosomatidae), with the descriptions of four new species and two new combinations

Abstract

The spider genus Sinoalaria Zhao & Li, 2014 is redefined and reviewed. A total of ten species are studied, including four new species: S. chi Yu & Lin, sp. nov. (♂♀), S. shenhei Yu & Lin, sp. nov. (♀), S. shuidi Yu & Lin, sp. nov. (♀), S. xiaotu Yu & Lin, sp. nov. (♂♀). Two new combinations are proposed: Sinoalaria nitida (Zhao & Li, 2012), comb. nov. and S. prolata (Zhao & Li, 2012), comb. nov., both transferred from Karstia Chen, 2010. The material of six known species were re-examined and photographed, including the type species, S. chengguanensis (Zhao & Li, 2012). A key is provided for all species of the genus, as well as diagnoses, illustrations, and a distribution map.


Zhang J, Feng C, Yu H, Lin Y (2023) A review of the spider genus Sinoalaria (Araneae, Theridiosomatidae), with the descriptions of four new species and two new combinations. ZooKeys 1173: 307-338. https://doi.org/10.3897/zookeys.1173.105123