The chromosome-level genome of Mesobuthus martensii provides insights into its evolution and the diversity of venom peptides

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  The chromosome-level genome of Mesobuthus martensii provides insights into its evolution and the diversity of venom peptides Abstract Mesobuthus martensii , the source species of the traditional Chinese medicine “Quanxie”, has long been utilized for its therapeutic properties. Venom peptides are recognized as the major active molecular basis of these pharmacological activities. Despite this, their development as therapeutic agents remains poorly explored. In this study, we performed an integrated multi-omics investigation to systematically explore the venom peptides of Mesobuthus martensii . We generated a chromosome-level genome assembly of Mesobuthus martensii using third-generation sequencing technologies, yielding a genome size of 1.08 Gb with a contig N50 of 46.46 Mb. Integrated genomic and transcriptomic analyses led to the identification of 51 putative novel venom peptide candidates. From the broader venom peptide set, five lysine- and arginine-rich candidates were select...

What a Long Strange Trip It's Been: Miocene Salinian Block Migration and the Biogeography of Megahexura Spiders

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What a Long Strange Trip It's Been: Miocene Salinian Block Migration and the Biogeography of Megahexura Spiders

ABSTRACT

Aim

In west-central California, the landscapes west of the San Andreas fault include the arc plutons of the Salinian block which form the geologic backbone of several South Coast mountain ranges. In the early Miocene Salinia was adjacent to the southern Sierra Nevada, but was subsequently captured by the Pacific Plate, with right-lateral slip migration displacing terranes northwestwards since the formation of the San Andreas fault. We hypothesise that a migrating Salinia has played an important role in the biogeographic history of dispersal-limited Megahexura mygalomorph spiders.

Location

Central and southern California Floristic Province, including Salinia (Santa Lucia, Sierra de Salinas, Gabilan, and Santa Cruz mountains), southern Sierra Nevada, and Transverse Ranges.

Taxon

Megahexura, Family Megahexuridae, Infraorder Mygalomorphae, Order Araneae.

Methods

Analyses of ultraconserved element (UCE) nuclear loci and single nucleotide polymorphism (SNP) data are used to estimate ingroup relationships and genetic population structuring, root placement and divergence timing, and a Bayesian-estimated biogeographic history of Megahexura.

Results

Phylogenomics strongly supports three primary phylogenetic lineages in Megahexura, with a common ancestor that diverged in the early to mid-Miocene, depending upon calibration parameters. The southern Sierra Nevada is reconstructed as the centre of origin for Megahexura, and one Megahexura lineage now resides mostly on ranges that include Salinian basement rocks. In the Santa Lucia Range, phylogenetic directionality is structured from north to south. The southern Sierra Nevada is also a more recent ancestral area for Megahexura populations currently occupying the western and southern Transverse Ranges, some of which have expanded northwestwards to secondarily contact Salinian populations.

Main Conclusions

We uncover a unique biogeographic history where instead of animal populations dispersing recently over an old landscape, phylogenomic patterns are best explained by the landscape itself moving, carrying animal populations. Our results are consistent with a compelling Salinian biogeography and represent a possible case of Neogene divergence driven principally by plate tectonics.


Hedin, M., & Monjaraz-Ruedas, R. (2026). What a Long Strange Trip It's Been: Miocene Salinian Block Migration and the Biogeography of Megahexura Spiders. Journal of Biogeography, 53(9), e70351. https://doi.org/10.1111/jbi.70351