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...

The largest Palaeozoic whip scorpion and the smallest (Arachnida: Uropygi: Thelyphonida); a new species and a new ichnospecies from the Carboniferous of New England, USA

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The largest Palaeozoic whip scorpion and the smallest (Arachnida: Uropygi: Thelyphonida); a new species and a new ichnospecies from the Carboniferous of New England, USA


Abstract

Palaeozoic fossils of whip scorpions (Arachnida: Uropygi: Thelyphonida) are extremely rare, with only seven species of this age previously described. A new species of fossil whip scorpion, as well as the first ichnospecies assignable to this group, are described here from the Carboniferous Narragansett Basin of Massachusetts, USA. A body fossil from the Rhode Island Formation (Moscovian) is referred to as Parilisthelyphonus bryantae gen. nov., sp. nov.. At more than 34 mm long it represents both the largest known Palaeozoic whip scorpion and the first fossil arachnid found in the Rhode Island Formation in ~130 years of scrutiny. The whip scorpion trace fossil, comprising a full-body impression and associated tracks, is described from the subjacent Wamsutta Formation (Late Bashkirian) of Massachusetts, USA as Inmontibusichnus charleshenryturneri  igen. nov., isp. nov.. With an estimated body length of less than 10 mm, the producer would be the smallest known Palaeozoic thelyphonid. These discoveries within the Narragansett Basin represent only the second site in the western hemisphere, in what was western Laurasia, to yield Palaeozoic whip scorpions. The Narragansett Basin is of significant Pangaean biogeographical importance among whip scorpion sites, being located between the westernmost Mazon Creek Lagerstätte of Illinois and the eastern assemblage of localities in Europe, and serves as an important new fossil calibration point for phylogenetic studies of this arachnid group.


Richard J Knecht and others, The largest Palaeozoic whip scorpion and the smallest (Arachnida: Uropygi: Thelyphonida); a new species and a new ichnospecies from the Carboniferous of New England, USA, Zoological Journal of the Linnean Society, 2023;, zlad088, https://doi.org/10.1093/zoolinnean/zlad088


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