ECOLOGICAL NICHE MODELS BY TITYUS SERRULATUS LUTZ & MELLO, 1922 AND TITYUS STIGMURUS (THORELL, 1876) (ARACHNIDA: SCORPIONES)

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  ECOLOGICAL NICHE MODELS BY TITYUS SERRULATUS LUTZ & MELLO, 1922 AND TITYUS STIGMURUS (THORELL, 1876) (ARACHNIDA: SCORPIONES) Summary Scorpions are venomous animals with high plasticity and can serve as models for biogeographical, natural history, and evolutionary studies. Ecological niche modeling can help in understanding essential characteristics of the geographic distribution of species, as well as allowing the prediction of future distribution patterns. Our objective was to model the ecological niche of the scorpion species *Tityus serrulatus * and *Tityus stigmurus* , as well as to identify the variables that influence their distribution in different biomes and their range limits in the Amazon, Caatinga, and Cerrado biomes. Data were obtained from 12 Brazilian arachnological collections. Bioclimatic variables were obtained from the WorldClim database, and niche modeling was implemented using the Maximum Entropy algorithm. The results showed that the Atlantic Forest bio...

On the venom system of centipedes (Chilopoda), a neglected group of venomous animals

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Toxicon

Volume 57, Issue 4, 15 March 2011, Pages 512-524

On the venom system of centipedes (Chilopoda), a neglected group of venomous animals (By Request)

Abstract

Centipedes are among the oldest extant terrestrial arthropods and are an ecologically important group of soil and leaf litter predators. Despite their abundance and frequent, often painful, encounters with humans, little is known about the venom and venom apparatus of centipedes, although it is apparent that these are both quite different from other venomous lineages. The venom gland can be regarded as an invaginated cuticle and epidermis, consisting of numerous epithelial secretory units each with its own unique valve-like excretory system. The venom contains several different enzymes, but is strikingly different to most other arthropods in that metalloproteases appear to be important. Myotoxic, cardiotoxic, and neurotoxic activities have been described, most of which have been attributed to high molecular weight proteins. Neurotoxic activities are also unusual in that G-protein coupled receptors often seem to be involved, either directly as targets of neurotoxins or indirectly by activating endogenous agonists. These relatively slow responses may be complemented by the rapid effects caused by histamines present in the venom and from endogenous release of histamines induced by venom cytotoxins. The differences probably reflect the ancient and independent evolutionary history of the centipede venom system, although they may also be somewhat exaggerated by the paucity of information available on this largely neglected group.


Undheim, E. A., & King, G. F. (2011). On the venom system of centipedes (Chilopoda), a neglected group of venomous animals. Toxicon, 57(4), 512-524. https://doi.org/10.1016/j.toxicon.2011.01.004