Two new arthropod toxins purified from the venom of the Mexican scorpion Centruroides nigrescens

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  Two new arthropod toxins purified from the venom of the Mexican scorpion Centruroides nigrescens Abstract The venom of the slender black scorpion Centruroides nigrescens , from the State of Guerrero México, was fractionated by Sephadex G–50 gel filtration, followed by carboxymethyl cellulose ion separation and high–performance liquid chromatography, permitting to obtain two new peptides toxic to arthropods. The estimate LD 50 of the soluble venom for the insect Acheta domesticus was 11.1 μg/g body weight, and for the arthropod Armadillidium vulgare was 61.1 μg body weight . The amino acid sequence of toxin Cnige1 (toxic to A. domesticus and A. vulgare ) contains 65 amino acids, with a molecular mass of 7273.37 mass units, whereas toxin Cnige2, toxic to A. domesticus , contains 68 amino acids, with a molecular mass of 7548.81 units. Both peptides are well packed, containing 8 cysteines, which in the native venoms are forming 4 disulfide bridges each. The amino acid sequences f...

Discovery of a new species of Eomysmauchenius from mid-Cretaceous Kachin amber (Araneae: Archaeidae)

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Discovery of a new species of Eomysmauchenius from mid-Cretaceous Kachin amber (Araneae: Archaeidae)

Abstract

Maybe living Archaeidae is only distributed in the southern, but all their fossils have been found in the northern hemisphere. Here, we report a new well-preserved fossil specimen from Kachin amber, which was identified to be a new species of genus Eomysmauchenius Wunderlich, 2008 through a series of morphological characteristics comparison, including a strongly raised cephalic part, a sclerotized ring around the spinnerets and a pedipalpal-cheliceral stridulatory organ absence, cheliceral peg teeth in an irregular position, the distal lateral margin of chelicera with a small triangular projection, length and height almost equal opisthosoma. The discovery of this new species once again increases fossil record diversity of the family Archaeidae in the Cretaceous, and unique palp structure enrich our knowledge of juvenal male pedipalps.

Yuan Peng, Chao Shi, Xiaoxuan Long, Michael S. Engel, Shuo Wang, Discovery of a new species of Eomysmauchenius from mid-Cretaceous Kachin amber (Araneae: Archaeidae), Cretaceous Research, 2023, 105703, ISSN 0195-6671, https://doi.org/10.1016/j.cretres.2023.105703.

(https://www.sciencedirect.com/science/article/pii/S0195667123002318)