Geographical distribution and new records of Ariamnes longissimus keyserling, 1891 (Araneae, Theridiidae) in South America

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  Geographical distribution and new records of Ariamnes longissimus keyserling, 1891 (Araneae, Theridiidae) in South America Abstract Ariamnes longissimus plays a relevant ecological role as a predator, yet its distribution remains underestimated, reflecting knowledge gaps. This study updates its distribution, reports new occurrences, and discusses biogeographic implications. Primary and secondary data (118 records) were compiled, georeferenced, and mapped according to biomes and political divisions. We report the first occurrence in Bahia (Northeast Brazil) and in the Cerrado. The species occurs in Argentina, Peru, and 10 Brazilian states, predominantly in the Atlantic Forest (78%) and Pampas (16%), with additional records in the Amazon and Cerrado. The concentration of records in southern and southeastern Brazil (94%) suggests either sampling bias or historical barriers, whereas its rarity in the Cerrado and absence in the Caatinga/Chaco indicate an association with humid enviro...

Leg autotomy in spiders from coastal wetlands of Kerala, India: natural history observations

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Leg autotomy in spiders from coastal wetlands of Kerala, India: natural history observations

ABSTRACT

Autotomy, or voluntary limb loss, is a widespread defence strategy among arthropods, yet its ecological costs and benefits in spiders remain poorly documented. Here, we report natural history observations of leg autotomy in 32 species across eight families from four coastal wetlands in Kerala, India. Patterns of autotomy varied widely among species. Many spiders, including members of the orb-weaving family Araneidae, shed legs at the coxa–trochanter joint, a mechanism that minimises haemolymph loss. Agile hunters such as members of the families Salticidae and Oxyopidae frequently autotomised multiple legs, with potentially severe consequences for locomotion. Notably, repeated cases in the jumping spider Carrhotus viduus (CL Koch) highlight the trade-offs faced by active hunters that depend heavily on agility. These findings highlight the taxonomic breadth, ecological variation and functional consequences of autotomy in spiders, underscoring its adaptive value while drawing attention to its hidden costs. We suggest that autotomy merits systematic study as an ecologically significant yet overlooked survival strategy in arachnids. This study presents the first broad field-based documentation of autotomy in spiders from Kerala, India, thereby extending current knowledge of its ecological relevance in tropical habitats.

Special thanks to Mathew M. Joseph (co-author) for sending me this full manuscript. 

Abraham, A., & Joseph, M. M. (2026). Leg autotomy in spiders from coastal wetlands of Kerala, India: natural history observations. Journal of Natural History, 60(9–12), 541–546. https://doi.org/10.1080/00222933.2026.2619579