Ontogenetic and geographic venom variation in the Great Basin Rattlesnake, Crotalus oreganus lutosus

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  Ontogenetic and geographic venom variation in the Great Basin Rattlesnake, Crotalus oreganus lutosus Abstract Venom composition among the species of the Western Rattlesnake clade is often quite variable, depending on several factors such as geographic location and ontogeny. Venom composition not only affects the ability of a snake to acquire prey efficiently, but it can also significantly impact snakebite symptomology. Currently, there has been limited characterization of the venom from the Great Basin Rattlesnake ( Crotalus oreganus lutosus ), a lineage that is broadly distributed in the intermontane western United States. In this study we sample 67 individual Great Basin Rattlesnakes collected in Idaho, Utah, California, and Arizona. We find evidence for substantial ontogenetic and geographic variation in venom composition. Of the six toxin families assessed, all showed ontogenetic shifts to varying extents, with some trends differing from those observed in other rattlesnake sp...

New Records of Loxosceles amazonica Gertsch, 1967 (Arachnida: Araneae: Sicariidae) from Tocantins, Brazil with Description of Female Genitalia Variation

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New Records of Loxosceles amazonica Gertsch, 1967 (Arachnida: Araneae: Sicariidae) from Tocantins, Brazil with Description of Female Genitalia Variation

Abstract

The knowledge of arachnofauna from Tocantins, Brazil, is still incipient. The present communication expands the known geographical distribution of Loxosceles amazonica Gertsch, 1967 (Arachnida: Araneae: Sicariidae) in Brazilian Cerrado. The brown spider specimens were sampled in Dianópolis municipality and Cristalândia municipality both in Tocantins State, Brazil, between 2022 and 2024. Also, we describe a new variation of the epigynum of L. amazonica. Mapping the distribution of Loxosceles Heineken & Lowe, 1832 species in Brazil is crucial for public health, aiding in prevention and timely treatment of loxoscelism caused by brown spider bites.

Madaleno, Kassia, and Lidianne Salvatierra. 2024. “New Records of Loxosceles Amazonica Gertsch, 1967 (Arachnida: Araneae: Sicariidae) from Tocantins, Brazil With Description of Female Genitalia Variation”. EntomoBrasilis 17 (December):e1093. https://doi.org/10.12741/ebrasilis.v17.e1093.