Qualitative and Quantitative Proteomic Analysis of Venoms from Mexican Rattlesnakes

  Qualitative and Quantitative Proteomic Analysis of Venoms from Mexican Rattlesnakes Abstract Despite the vast biodiversity of Mexican vipers, venom of endemic species has been barely studied. Here we analyzed the venom composition of three endemic species of rattlesnakes: Crotalus aquilus , C. triseriatus , and C. ravus . We used quantitative chromato-mass-spectrometry and compared venoms with C. molossus , a species commonly found in North America, in a comparative and phylogenetic framework. In total, we identified 165 proteins grouped in 19 main protein families, consistent with previous reports for viperid venoms. In C. aquilus and C. triseriatus , the most predominant protein-family type was Serine Proteases, and in C. triseriatus and C. molossus it was Snake Venom Metalloproteases. The Label-free quantification revealed a high proportion of Snake Venom Metalloproteases in C. aquilus , C. triseriatus , and C. molossus , reaching 28–47% of the total venom. In contrast, in ...

Phylogeography and evolutionary history of the burrowing scorpion genus Scorpio Linnaeus, 1758 (Scorpiones: Scorpionidae) in the Mediterranean Basin

 


Phylogeography and evolutionary history of the burrowing scorpion genus Scorpio Linnaeus, 1758 (Scorpiones: Scorpionidae) in the Mediterranean Basin

Abstract

The burrowing scorpions of the genus Scorpio Linnaeus, 1758 were considered to be a single polymorphic species, Scorpio maurus Linnaeus, 1758, distributed from West Africa across the Sahel and the Saharan highlands through the Maghreb and the Middle East, to Iran. After various revisions, the complex was treated as including 18 species and seven subspecies. Five additional new Scorpio species were recently described. However, doubts remain regarding the validity of these taxa due to the lack of reliable characters and the lack of genetic data for many species. The aim of the present study was to analyze the phylogenetic relationships and the evolutionary events that promoted diversification within the genus. Phylogenetic analyses were performed using 633 base pairs of the mitochondrial COI gene from 51 individuals collected in Tunisia, Morocco, and Egypt, combined with 74 previously published sequence data. Phylogenetic analyses revealed twenty distinct lineages forming two geographically separate clades, a Maghrebian clade and a Middle Eastern clade. Although most named species formed distinct lineages, various additional lineages were identified, highlighting potential unnamed species. Divergence time estimates indicate that the division within the genus Scorpio began during the Mid-Miocene, a period characterized by tectonic events coupled with climatic oscillations. Further differentiation occurred during the Miocene-Pliocene transition when climatic fluctuations resumed and the Mediterranean became increasingly arid. Speciation within the genus Scorpio may have been driven by the expansion of the savannas and Sahara Desert, the associated reduction of a once widespread rainforest into numerous micro-refugia in the mountains of the Mediterranean region, and by adaptation to these new habitats.

Khammassi, M., Nouira, S., Badry, A. et al. Phylogeography and evolutionary history of the burrowing scorpion genus Scorpio Linnaeus, 1758 (Scorpiones: Scorpionidae) in the Mediterranean Basin. Org Divers Evol (2024). https://doi.org/10.1007/s13127-024-00649-8