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...

The presence of the Dinaric genus Mesostalita Deeleman-Reinhold, 1971 (Arachnida: Araneae: Dysderidae) in the Julian Prealps (NE Italy)

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The presence of the Dinaric genus Mesostalita Deeleman-Reinhold, 1971 (Arachnida: Araneae: Dysderidae) in the Julian Prealps (NE Italy)

Abstract

Mesostalita is a genus of woodlouse hunter spiders (Arachnida: Araneae: Dysderidae), currently including three species: M. nocturna, M. kratochvili, and M. comottii. These are cave-dwelling species, endemic to the Dinarides. The genus distribution range is examined, focusing on published localities. In particular, the presence of Mesostalita in the Julian Prealps (NE Italy) is investigated by researching previous reports from the area. A new record, Foran di Landri cave, is reported, representing the fourth known occurrence of the genus in the area. A brief description and some photographs of the female specimen found in the cave are provided. Following this finding, the genus distribution range must be extended northwards to include the Julian Prealps, on the other side of the Isonzo-Soča river (representing a biogeographical barrier for many cave-dwellers), opposite to the Dinarides. This makes Mesostalita one of the few troglobitic north-western Dinaric genera living on both sides of the river. Further sampling in caves in the area (to find at least a male individual) and molecular analyses are necessary to clarify the proper, specific status of specimens living in the Julian Prealps and their phylogenetic relationships within the genus.

Canciani, G., Turolo, L., Tringali, L., Colautti, M., & Colla, A. (2025). The presence of the Dinaric genus Mesostalita Deeleman-Reinhold, 1971 (Arachnida: Araneae: Dysderidae) in the Julian Prealps (NE Italy). Acta Carsologica, 54(1). https://doi.org/10.3986/ac.v54i1.13918