Spiders (Order Araneae) are massively abundant generalist arthropod predators that are found in nearly every ecosystem on the planet and have persisted for over 380 million years. Spiders have long served as evolutionary models for studying complex mating and web spinning behaviors, key innovation and adaptive radiation hypotheses, and have been inspiration for important theories like sexual selection by female choice. Unfortunately, past major attempts to reconstruct spider phylogeny typically employing the “usual suspect” genes have been unable to produce a well-supported phylogenetic framework for the entire order. To further resolve spider evolutionary relationships we have assembled a transcriptome-based data set comprising 70 ingroup spider taxa. Using maximum likelihood and shortcut coalescence-based approaches, we analyze eight data sets, the largest of which contains 3,398 gene regions and 696,652 amino acid sites forming the largest phylogenomic analysis of spider relationships produced to date. Contrary to long held beliefs that the orb web is the crowning achievement of spider evolution, ancestral state reconstructions of web type support a phylogenetically ancient origin of the orb web, and diversification analyses show that the mostly ground-dwelling, web-less RTA clade diversified faster than orb weavers. Consistent with molecular dating estimates we report herein, this may reflect a major increase in biomass of non-flying insects during the Cretaceous Terrestrial Revolution 125–90 million years ago favoring diversification of spiders that feed on cursorial rather than flying prey. Our results also have major implications for our understanding of spider systematics. Phylogenomic analyses corroborate several well-accepted high level groupings: Opisthothele, Mygalomorphae, Atypoidina, Avicularoidea, Theraphosoidina, Araneomorphae, Entelegynae, Araneoidea, the RTA clade, Dionycha and the Lycosoidea. Alternatively, our results challenge the monophyly of Eresoidea, Orbiculariae, and Deinopoidea. The composition of the major paleocribellate and neocribellate clades, the basal divisions of Araneomorphae, appear to be falsified. Traditional Haplogynae is in need of revision, as our findings appear to support the newly conceived concept of Synspermiata. The sister pairing of filistatids with hypochilids implies that some peculiar features of each family may in fact be synapomorphic for the pair. Leptonetids now are seen as a possible sister group to the Entelegynae, illustrating possible intermediates in the evolution of the more complex entelegyne genitalic condition, spinning organs and respiratory organs.
Posts Tagged ‘systematics’
Two new species of the mexicanus group of Vaejovis C.L. Koch are described from the Madrean pine-oak forests of the Sierra Madre Occidental in the state of Durango, Mexico. These species, Vaejovis sierrae sp. nov. and Vaejovis mcwesti sp. nov., are distinguished from each other and the only other species of the mexicanus group known from this mountain range, Vaejovis montanus Graham and Bryson, by morphometrics, carinal development of the pedipalps, granulation of the metasoma, and body size. A key to the species of the mexicanus group from the Sierra Madre
Sissom WD, Graham MR, Donaldson TG, Bryson Jr RW. Two new Vaejovis C.L. Koch 1836 from highlands of the Sierra Madre Occidental, Durango, Mexico (Scorpiones, Vaejovidae). Insecta Mundi. 2016 (0477):1-14. [Open Access]
A new species of vaejovid scorpion from northern California, Pseudouroctonus maidu sp. n., is named and described. This new species appears to be most similar to Pseudouroctonus iviei (Gertsch & Soleglad, 1972) and Pseudouroctonus glimmei (Hjelle, 1972).
California, Kovarikia, Pseudouroctonus, taxonomy, Vaejovinae
Recent fieldwork in northern California has revealed the presence of a previously undescribed species in the vaejovid scorpion genus Pseudouroctonus Stahnke, 1974. To facilitate its inclusion in discussions of ongoing systematic and phylogeographic studies of Pseudouroctonus and its near relatives (Francke and Savary 2006,Bryson et al. 2013, Bryson et al. 2014, and others in preparation), the new species is named and described herein. It represents the third species of Pseudouroctonus in California, all endemic to the state, and only the fourth new species of scorpion to be described from California in the past twenty years.
Eight New Species of Charinus Simon, 1892 (Arachnida: Amblypygi: Charinidae) Endemic for the Brazilian Amazon, with Notes on Their Conservational StatusAdministrator on February 23, 2016 in Online Arachnid Publications, Recent News, Scorpion Images, Spider News in North America No Comments »
Great Article not relevant to North America but wonderful to the Americas in general.
Eight new species of Charinus Simon, 1892 are described for the Brazilian Amazon, from the states of Pará (C. bichuetteae sp. n., C. bonaldoi sp. n., C. carajas sp. n., C. ferreus sp. n., C.guto sp. n. and C. orientalis sp. n.) and Amazonas (Charinus brescoviti sp. n. and C. ricardoi sp. n.). All new species can be differentiated from the other species of the genus by the number of pseudo-articles in basitibia IV, the presence/absence of median eyes, and the shape of the female gonopod. Brazil now becomes the country with the largest diversity of Amblypygi in the world, with 25 known species. Half of the new species described here have a high degree of endangerment: C. bichuetteae sp. n. is threatened by the flood caused by the hydroelectric dam of Belo Monte, and C. carajas sp. n., C. ferreus sp. n. and C. orientalis sp. n. are endangered by the iron mining in Carajás municipality and surroundings. The Charinus species here described are endemic to the Amazon Region, so in order to assure their preservation, it is strongly recommended a special care with their habitats (type localities) which are facing increasing rates of destruction and deforestation.
Taxonomic revision of the tarantula genus Aphonopelma Pocock, 1901 (Araneae, Mygalomorphae, Theraphosidae) within the United StatesAdministrator on February 4, 2016 in Online Arachnid Publications, Recent News, Spider News in North America No Comments »
This systematic study documents the taxonomy, diversity, and distribution of the tarantula spider genusAphonopelma Pocock, 1901 within the United States. By employing phylogenomic, morphological, and geospatial data, we evaluated all 55 nominal species in the United States to examine the evolutionary history of Aphonopelma and the group’s taxonomy by implementing an integrative approach to species delimitation. Based on our analyses, we now recognize only 29 distinct species in the United States. We propose 33 new synonymies (A. apacheum, A. minchi, A. rothi, A. schmidti, A. stahnkei = A. chalcodes; A.arnoldi = A. armada; A. behlei, A. vogelae = A. marxi; A. breenei = A. anax; A. chambersi, A. clarum, A.cryptethum, A. sandersoni, A. sullivani = A. eutylenum; A. clarki, A. coloradanum, A. echinum, A. gurleyi, A.harlingenum, A. odelli, A. waconum, A. wichitanum = A. hentzi; A. heterops = A. moderatum; A. jungi, A.punzoi = A. vorhiesi; A. brunnius, A. chamberlini, A. iviei, A. lithodomum, A. smithi, A. zionis = A. iodius; A.phanum, A. reversum = A. steindachneri), 14 new species (A. atomicumsp. n., A. catalinasp. n., A.chiricahuasp. n., A. icenogleisp. n., A. johnnycashisp. n., A. maderasp. n., A. marekisp. n., A. moellendorfisp. n., A. parvumsp. n., A. peloncillosp. n., A. prenticeisp. n., A. saguarosp. n., A. superstitionensesp. n., and A. xwalxwalsp. n.), and seven nomina dubia (A. baergi, A. cratium, A. hollyi, A. mordax, A. radinum, A.rusticum, A. texense). Our proposed species tree based on Anchored Enrichment data delimits five major lineages: a monotypic group confined to California, a western group, an eastern group, a group primarily distributed in high-elevation areas, and a group that comprises several miniaturized species. Multiple species are distributed throughout two biodiversity hotspots in the United States (i.e., California Floristic Province and Madrean Pine-Oak Woodlands). Keys are provided for identification of both males and females. By conducting the most comprehensive sampling of a single theraphosid genus to date, this research significantly broadens the scope of prior molecular and morphological investigations, finally bringing a modern understanding of species delimitation in this dynamic and charismatic group of spiders.
See also the National Geographic article at http://news.nationalgeographic.com/2016/02/160204-animals-spiders-tarantulas-science-nation/
LiveScience review at http://www.livescience.com/53616-tarantula-named-for-johnny-cash.html
Scorpions are among the oldest terrestrial arthropods, which are distributed worldwide, except for Antarctica and some Pacific islands. Scorpion envenomation represents a public health problem in several parts of the world. Mexico harbors the highest diversity of scorpions in the world, including some of the world’s medically important scorpion species. The systematics and diversity of Mexican scorpion fauna has not been revised in the past decade; and due to recent and exhaustive collection efforts as part of different ongoing major revisionary systematic projects, our understanding of this diversity has changed compared with previous assessments. Given the presence of several medically important scorpion species, the study of their venom in the country is also important. In the present contribution, the diversity of scorpion species in Mexico is revised and updated based on several new systematic contributions; 281 different species are recorded. Commentaries on recent venomic, ecological and behavioral studies of Mexican scorpions are also provided. A list containing the most important peptides identified from 16 different species is included. A graphical representation of the different types of components found in these venoms is also revised. A map with hotspots showing the current knowledge on scorpion distribution and areas explored in Mexico is also provided.
See here at http://www.mdpi.com/2072-6651/8/1/2
Two new species of Pseudouroctonus are described from southeastern Arizona, USA, Pseudouroctonus santarita, sp. nov. from the Santa Rita Mountains and P. kremani, sp. nov. from the Santa Catalina Mountains. These new species are closely related to P. apacheanus (Gertsch et Soleglad, 1972). A combination of morphological differences in the hemispermatophore, the mating plug, and several morphometric-based characters are identified as diagnostic. New substructures are identified for the mating plug.
URL in PDF Format : http://www.science.marshall.edu/fet/euscorpius/p2015_211.pdf
Scorpion fossils are possibly more diverse than you might expect. 128 fossil species are currently recognized, with some dating back as far as the Silurian period. They occur in various different rock types and also, more rarely, as inclusions in amber.
Follow the Link for more information and browse Siri Scientific Press. http://siriscientificpress.co.uk/blogs/news/68263875-new-fossil-scorpion-290-million-years-old-sheds-important-light-on-their-evolutionary-history