Evidence of venom variability associated with venom extraction interval in the monocled cobra (Naja kaouthia)

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  Evidence of venom variability associated with venom extraction interval in the monocled cobra (Naja kaouthia) Abstract Snake venom variability is a critical factor in antivenom production. Although several influencing factors have been studied, the impact of extraction interval on venom properties remains poorly understood. This study evaluated the effects of various extraction intervals on venom yield, the percentage of dry weight (%Dw), and composition in the monocled cobra ( Naja kaouthia ). Twenty-five captive snakes were randomly allocated to five groups, each undergoing a control extraction followed by a repeated extraction at 1, 4, 7, 10, or 14 days. Venom profiles were characterized using reversed-phase high-performance liquid chromatography (RP-HPLC) and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Results indicated that while fresh venom yield remained stable across all intervals, %Dw significantly decreased in extractions performed between 1 and 10 days, ...

Comparative morphology of stridulating setae of Theraphosinae (Araneae: Theraphosidae)

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Comparative morphology of stridulating setae of Theraphosinae (Araneae: Theraphosidae) 

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Zoologischer Anzeiger

Volume 283, November 2019, Pages 58-68

Abstract


Theraphosid spiders are repleted with cuticular structures that evolved into distinct morphologies and developed different functions. The stridulatory apparatus present in the subfamily Theraphosinae is composed by a group of setae and opposed organs (ridged surface) that emit sound through friction. Only sixteen genera of Theraphosinae spiders were reported with stridulatory setae: Acanthoscurria, Aguapanela, Brachypelma, Citharacanthus, Cyrtopholis, Grammostola, Hemirrhagus, Lasiodora, Longilyra, Nhandu, Theraphosa, Pamphobeteus, Phormictopus, Proshapalopus, Pterinopelma and Vitalius. Besides these stridulating setae, other cuticular structures have been traditionally used in Theraphosinae taxonomy: the plumose scopula on the lateral faces of femora I and IV. However, the ultrastructure of these setae and scopulae was never studied in detail. Here, we analyzed the diversity of cuticular structures on coxae, trochanters and femora of Theraphosinae spiders using SEM. Beside the description of plumose and claviform stridulating setae on femora, we established five distinct variations of stridulatory setae found on coxae and trochanters and report their presence for the genus Megaphobema, Crassicrus and Cotztetlana for the first time.

Galleti-Lima, A., & Guadanucci, J. P. L. (2019). Comparative morphology of stridulating setae of Theraphosinae (Araneae: Theraphosidae). Zoologischer Anzeiger, 283, 58-68. https://doi.org/10.1016/j.jcz.2019.08.010