Thrombocytopenia induced by viperid snake venoms in a murine model and its neutralization by a polyvalent antivenom

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  Thrombocytopenia induced by viperid snake venoms in a murine model and its neutralization by a polyvalent antivenom Abstract Thrombocytopenia is a common manifestation in viperid snakebite envenomings, contributing to systemic bleeding and hemodynamic alterations. Despite its relevance, this effect is not evaluated when assessing the neutralizing ability of antivenoms. In this study we present an in vivo method in mice for the quantification of thrombocytopenic effect. Representative venoms of Costa Rican viperid snake genera ( Atropoides , Bothrops , Bothriechis , Cerrophidion , Crotalus , Lachesis , Metlapilcoatlus , and Porthidium ) were administered by the intramuscular route in mice and platelet counts were carried out 3 h after envenoming. Only the venoms of Bothrops asper and Bothriechis lateralis induced a significant drop in platelet numbers as compared to controls receiving saline solution. The polyvalent antivenom used in Central America was effective in the neutral...

Functional Divergence of Scorpion Pedipalps: Musculoskeletal Specialization Toward Opposing Performance Optima

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Functional Divergence of Scorpion Pedipalps: Musculoskeletal Specialization Toward Opposing Performance Optima

ABSTRACT

When selective pressures for different functions act simultaneously on a structure, morphological diversification can be shaped by adaptation toward distinct functional optima. Systems may evolve along a performance gradient, optimizing different aspects of function in response to ecological demands. We investigated two scorpion species representing the morphological extremes of chela (pincer) shape. Scorpion chelae exhibit remarkable morphological diversity associated with ecological roles, and their performance varies along a force-velocity continuum. To explore how structural and muscular adaptations shape performance, we developed a biomechanical model integrating synchrotron microtomography, muscle architecture, and performance data. Our findings reveal that these species exhibit distinct structural and muscular arrangements, each optimized for a different performance outcome. The short-fingered species maximize closing force through increased mechanical advantage and longer sarcomeres, enhancing muscle contraction efficiency. In contrast, the slender-chela species optimizes closing velocity through muscle orientations that favor rapid acceleration. While additional functional demands likely influence these designs, one morphology appears specialized for quickly capturing prey, while the other seems to be adapted for prey crushing. These divergent performance optima may have played a key role in shaping the trophic ecology of scorpions and influencing the evolution of their venom.

Simone, Y., Herrel, A., & Boistel, R. (2025). Functional Divergence of Scorpion Pedipalps: Musculoskeletal Specialization Toward Opposing Performance Optima. Journal of Morphology, 286(5), e70055. https://doi.org/10.1002/jmor.70055