Big Spider, Big Genome: Chromosome-level genome of a North American tarantula (Aphonopelma marxi) and comparative genomics across 300 million years of spider evolution

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  Image Credit: WikiCommons Big Spider, Big Genome: Chromosome-level genome of a North American tarantula (Aphonopelma marxi) and comparative genomics across 300 million years of spider evolution Abstract The comparison of chromosome-level genomes allows biologists to investigate new axes of organismal evolution. Spiders comprise a significant proportion of known arachnid diversity, with many complex morphologies and unique natural histories, yet comparative genomics in spiders has been limited due to the number of available genomes. We present a de novo chromosomal reference genome of a mature male tarantula, Aphonopelma marxi, and comparatively examine spider genome evolution across the Order Araneae. Using PacBio HiFi and Hi-C sequencing, the final 6.5 Gb assembly consists of 17 autosomes, 1 X chromosome, and 127 unplaced scaffolds, with an N50 of 370 Mb and Arachnida (odb10; 2934 genes) BUSCO of 96.7%. By comparing 20 additional spider genomes from 15 families, we find mygalomo...

A revision of the genus Trachelas L. Koch, 1872 (Araneae: Trachelidae) in the continental Afrotropical Region

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A revision of the genus Trachelas L. Koch, 1872 (Araneae: Trachelidae) in the continental Afrotropical Region

Abstract

The polyphyletic spider genus Trachelas L. Koch, 1872, with the type species T. minor O. Pickard-Cambridge, 1872 from Europe (also known in North Africa and Central Asia), has a worldwide distribution in the tropical, subtropical and temperate regions, although Trachelas sensu stricto is restricted to the Old World. Here the continental Afrotropical species are revised and a description of Trachelas sensu stricto is provided. Trachelas canariensis Wunderlich, 1987, T. chubbi Lessert, 1921, T. pusillus Lessert, 1923 and T. sylvae Caporiacco, 1949 are redescribed, and the female of T. pusillus described for the first time. Seven new species are described: T. falsus sp. nov. (♂ ♀, Côte d’Ivoire, Nigeria, South Africa and Tanzania), T. humus sp. nov. (♂ ♀, Namibia and South Africa), T. leggi sp. nov. (♂ ♀, South Africa), T. longinquus sp. nov. (♂, Central African Republic), T. russellsmithi sp. nov. (♀, Ethiopia), T. scutatus sp. nov. (♂ ♀, Ghana and Nigeria) and T. smithi sp. nov. (♀, Kenya). The female of Trachelas scopulifer Simon, 1896 is redescribed, its male is described for the first time, and its transfer to Thysanina Simon, 1910 proposed. The immature female type of T. punctatus Simon, 1886 from Senegal is presumed lost and this species is considered a nomen dubium. A key to the continental species of Afrotropical Trachelas is provided. A molecular phylogeny based on the cytochrome oxidase subunit I gene (COI) indicates that the New World species of the genus belong to a distinct lineage and are only distantly related to Trachelas sensu stricto.

Haddad, C. R. & Lyle, R. (2025). A revision of the genus Trachelas L. Koch, 1872 (Araneae: Trachelidae) in the continental Afrotropical Region. Zootaxa 5673(4): 451-493. doi:10.11646/zootaxa.5673.4.1