Hidden diversity in plain sight: four new species of Nemesia (Araneae: Mygalomorphae) from the Córdoba Province of Spain

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  Hidden diversity in plain sight: four new species of Nemesia (Araneae: Mygalomorphae) from the Córdoba Province of Spain Abstract A taxonomic revision of the species of Nemesia Audouin, 1826, distributed in the vicinity of Córdoba City, southern Spain, is presented. Four new species are described: Nemesia morana sp. nov. (female), N. kodama sp. nov. (male and female), N. rosae sp. nov. (male and female), and N. tamajoni sp. nov. (male and female). These species are distinguished by distinct morphological characters, including the shape of the spermathecae, palpal bulbs, and spinnerets, as well as by burrow architecture. Fieldwork was conducted across two of the three major habitat types in the region—the humid, forested mountains of Sierra Morena and the croplands and riparian forests of the Guadalquivir Valley—while the third, the “campiña”, which is mainly composed of agricultural landscapes, remains poorly explored. Sampling methods included pitfall trapping and the direct e...

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 secretory proteins, suggesting evolutionary divergence. Electrophoretic and enzymatic assays demonstrated species- and population-specific differences in phospholipase A₂, acetylcholinesterase, hyaluronidase, L-amino acid oxidase, phosphodiesterase, and protease activities. Cytotoxicity assays on human fibroblasts and mouse myoblasts showed that N. kaouthia (southern) and N. fuxi venoms caused the most potent and time-dependent cell damage, whereas central N. kaouthia and king cobra (Ophiophagus hannah) venoms were less cytotoxic. Immunoreactivity and neutralisation assays indicated that the species-specific monovalent antivenom effectively binds and neutralises cobra venoms, while neuro-polyvalent antivenom provides moderate cross-protection, and haemato-polyvalent antivenom is highly specific to viperid venom. These findings reveal substantial inter- and intraspecific venom variation in Thai cobras, emphasising the importance of population-level considerations in antivenom design and snakebite management. Continuous evaluation of venom composition and antivenom efficacy is essential to optimise clinical outcomes across Thailand’s diverse landscapes.
Ratnarathorn, N., Panyain, N., Noiphrom, J., Thaveekarn, W., Taewcharoen, N., Khow, O., Chanhome, L., Laoungbua, P., Tawan, T., & Kumkate, S. (2026). 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. Acta Tropica, 108065. https://doi.org/10.1016/j.actatropica.2026.108065