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...

Webs of intrigue: museum genomics elucidate relationships of the marronoid spider clade (Araneae)

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Webs of intrigue: museum genomics elucidate relationships of the marronoid spider clade (Araneae) 

Abstract

Relationships among spider families that lack support through other lines of evidence (e.g., morphology) have recently been uncovered through molecular phylogenetics. One such group is the “marronoid” clade, which contains about 3,400 described species in 9 families. Marronoids run the gamut of life history strategies, with social species, species producing a variety of silk types, and species occurring in a range of extreme environments. Despite recognition of the ecological variability in the group, there remains uncertainty about family- level relationships, leaving diverse ecologies without an evolutionary context. The phylogenies produced to date have relatively low nodal support, there are few defined morphological synapomorphies, and the internal relationships of many families remain unclear. We use 93 exemplars from all marronoid families and ultraconserved element loci captured in silico from a combination of 48 novel low-coverage whole genomes and genomic data from the Sequence Read Archive (SRA) to produce a 50% occupancy matrix of 1,277 loci from a set of ultraconserved element probes. These loci were used to infer a phylogeny of the marronoid clade and to evaluate the familial relationships within the clade, and were combined with single-locus (Sanger) legacy data to further increase taxonomic sampling. Our results indicate a clearly defined and well-supported marronoid clade and provide evidence for both monophyly and paraphyly within the currently defined families of the clade. We propose taxonomic changes in accordance with the resulting phylogenetic hypothesis, including elevating Cicurinidae (restored status) and Macrobunidae (new rank).

Jacob A Gorneau, Sarah C Crews, Franklyn Cala-Riquelme, Katherine O Montana, Joseph C Spagna, Francesco Ballarin, Lina M Almeida-Silva, Lauren A Esposito, Webs of intrigue: museum genomics elucidate relationships of the marronoid spider clade (Araneae), Insect Systematics and Diversity, Volume 7, Issue 5, September 2023, 5, https://doi.org/10.1093/isd/ixad021