On the identity of the poorly known spider species Centromerus obscurus Boesenberg, 1902 and description of a new species (Araneae: Linyphiidae)

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  On the identity of the poorly known spider species Centromerus obscurus Boesenberg, 1902 and description of a new species (Araneae: Linyphiidae) Abstract The taxonomic status and distribution of the poorly known linyphiid species Centromerus obscurus Boesenberg, 1902 is discussed on the basis of newly collected material from Bulgaria. Additionally, after a review of the related literature and the newly collected material, a new species of Centromerus species, C. thaleri sp. n., is described based on both sexes and Centromerus obscurus is considered nomen dubium stat. reconf.  Deltshev, C. & Indzhov, S. (2026). On the identity of the poorly known spider species Centromerus obscurus Boesenberg, 1902 and description of a new species (Araneae: Linyphiidae). Historia Naturalis Bulgarica 48 (6): 159-164. doi: 10.48027/hnb.48.062

Comparative analyses of Bothrops fonsecai snake venom: individual variability and sex-based differences

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Comparative analyses of Bothrops fonsecai snake venom: individual variability and sex-based differences

Abstract

Snakebite envenomation is a neglected tropical disease affecting thousands of people globally, especially in tropical and subtropical regions. An estimated 81,000 to 138,000 deaths occur annually, with many survivors experiencing permanent disabilities. In Brazil, around 26,000 cases are reported each year, with the genus Bothrops responsible for 83.8% of them. Bothrops venoms are rich in metalloproteases, serine proteases, phospholipases A2, and L-amino acid oxidases, which can cause hemorrhage, tissue necrosis, coagulation disorders, and hypotension. This study focuses on the biochemical and toxicological characterization of Bothrops fonsecai venom, an understudied and near-threatened species endemic to southeastern Brazil, not included in the venom pool for antibotropic serum preparation. Venoms from male and female specimens maintained at the Butantan Institute were compared using standard biochemical, enzymatic, immunological assays, and protein composition. Females tented to exhibited higher enzymatic activity than males in nearly all tests performed. Significant differences were found in EC50 values for indirect hemolysis and in the minimum coagulant dose, also indicating sex-based variation in venom potency. SDS-PAGE and RP-HPLC analyses revealed qualitative and quantitative differences in protein composition between sexes and individually. Immunological assays (ELISA and Western Blotting) demonstrated good immune recognition patterns, with only a few exceptions, which may reflect intraspecific variability in venom antigenicity. Although some biochemical information on Bothrops fonsecai is available, studies remain scarce and fragmented. This work advances current knowledge by providing a broader characterization of the venom and by examining intraspecific patterns—such as sex-related and individual variation—that had not been previously explored in an integrated way. These findings contribute to a more complete understanding of the species, which is especially relevant given its limited representation in venom research and may contribute to improving the effectiveness of antivenom therapies and clinical management of envenomations caused by this species.
Gabriel, L. S., Venancio Lima, E. O., Tavares Perrotti, P. H., Francisco Alves, L. D. C., & Tanaka-Azevedo, A. M. (2026). Comparative analyses of Bothrops fonsecai snake venom: Individual variability and sex-based differences. Toxicon, 108997. https://doi.org/10.1016/j.toxicon.2026.108997