Interspecific and Intraspecific Variation in Venom Proteomics, Composition, and Antivenom Efficacy of Thai Cobras (Naja spp.): Highlighting the Distinct Profile of the Newly Identified Naja fuxi

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  Interspecific and Intraspecific Variation in Venom Proteomics, Composition, and Antivenom Efficacy of Thai Cobras (Naja spp.): Highlighting the Distinct Profile of the Newly Identified Naja fuxi Abstract Cobras ( Naja  spp.) account for a significant number of snakebite incidents in Thailand. The monocled cobra ( Naja kaouthia ) has historically been considered the only non-spitting species, but recent evidence indicates population-level diversification in central and southern regions. Additionally, a newly described non-spitting species, the mountain cobra ( Naja fuxi ), has been identified in mountainous areas. This study investigates venom variation among Thai  Naja  species and populations and evaluates the efficacy of monovalent and polyvalent Thai antivenoms. Proteomic analyses revealed that three-finger toxins dominate  Naja  venoms, whereas  N. fuxi  exhibits a distinct profile enriched in snake venom metalloproteinases and cysteine-rich...

Thinking small: miniaturization might have facilitated adaptation to new niches in tarantulas

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Thinking small: miniaturization might have facilitated adaptation to new niches in tarantulas

Abstract

The interplay between ecology and morphology holds significant importance in the field of evolutionary ecology. Miniaturization, a prevalent trend across diverse branches of the tree of life, often emerges as a consequence of adaptation to specific ecological niches. However, the causes and outcomes of miniaturization can vary significantly among different taxa. In our study, we utilized tarantulas as a model system to explore whether microhabitat choices are linked to morphological characteristics. Specifically, we examined whether the transition to a non-burrowing, ground-dwelling lifestyle is associated with miniaturization. Our findings indicate that the evolution of morphological traits in tarantulas has primarily been influenced by stabilizing selection, with no discernible difference in morphotypes associated with fossorial or arboreal habits. Nevertheless, we observed that whenever tarantulas opportunistically transitioned to a non-burrowing, ground-dwelling lifestyle—such as living under rocks, logs, or within crevices—they seem to have undergone body-form miniaturization and a reduction in the ratio of forelimb to hindlimb length. This study underscores the potential for repeated shifts to unique ecological niches to disrupt the conventional trajectory of morphological evolution, resulting in the emergence of novel phenotypes.

Biswas, A., & Karanth, K. P. Thinking small: Miniaturization might have facilitated adaptation to new niches in tarantulas. Zoological Journal of the Linnean Society. https://doi.org/10.1093/zoolinnean/zlae069