Toxicon. ;20(6) Envenomation by the Mexican lance-headed rattlesnake Crotalus polystictus: a case report. Hardy DL. A case of envenomation by. PDF | On Sep 30, , Rubén Alonso Carbajal Márquez and others published Crotalus polystictus. Diet. Genus: Crotalus. Species: polystictus. Common Names Mexican Lance-headed Rattlesnake, Mexican Lancehead Rattlesnake. Local Names Chiauhcoatl.

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This result is consistent with the GM approach using deformation grids, which showed shifts in landmark configurations in mean male head shape relative to mean female head shape Fig.

In summary, compared with females, males had relatively larger heads, differed in head shape, and showed stronger evidence of allometry in head shape. This file is licensed under the Creative Commons Attribution 3. Adults of both males and females ate predominately mice and voles; however, males also consumed a greater proportion of larger mammalian species, and fewer small prey polysictus. Both males and females principally consumed mice and voles Sexual dimorphism in the shape or relative size of structures that may not directly influence reproductive success e.

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Finally, to visualize shape differences, we used deformation grids based on the mean landmark configurations for male and female samples, designating females as the reference shape. The following other wikis use this file: Close mobile search navigation Article navigation. Finally, we calculated Renkonen Index percentage overlap in male and female diets Krebs, to estimate the magnitude of dietary divergence between sexes.

These data were culled from a comprehensive study of C. We excluded neonates because of the comparatively poor resolution of head features from photographs, low sample sizes, and risks associated with prolonged exposure to anaesthesia in small snakes. We selected an image crktalus each rattlesnake that best crotalsu the two-dimensional shape of the dorsal aspect of the head, and then digitized these images for three fixed landmarks and twenty sliding semi-landmarks using TPSDIG2 Rohlf, Fig.


Male body size is positively correlated with mating success in species known to have male combat Shine,but we are unaware of any published data or analyses evaluating the relationship between head morphology and mating success in snakes. Shared dependence on mice and voles accounted for most resource overlap; overlap in the use of these prey species represented The Venomous Reptiles of Latin America.

The variation in patterns of head dimorphism detected from the few studies available suggests that rattlesnakes may exhibit greater variation in polysttictus differences between sexes, as well as other aspects of intersexual niche divergence, than has previously been appreciated. Abstract Sexual dimorphism of phenotypic traits associated with resource use is common in animals, polystictsu may result from niche divergence between sexes. Open circles, females; filled circles, males.

An emerging generality is that the direction and degree of sexual size dimorphism SSD is at least partly determined by the strength crotalux and interactions between forces acting on sexual selection. From Wikimedia Commons, the free media repository.

Crotalus polystictus | The Reptile Database

However, because the sexes overlapped greatly in diet, we hypothesize that diet and head dimorphisms in C. Herpetological Review 47 2: Web pages and scripting Jiri Hosek.

The positive allometry of head shape observed in males but absent in females is consistent with adaptation for expanded size range of prey species by males.

The bitten limb must not be exercised as muscular contraction will promote systemic absorption of venom. Wiping it once with a damp polystlctus to remove surface venom is unlikely to do much harm or good but the wound must not be massaged. The species is found on the plateau of central Mexico from southern Zacatecas and northeastern Colima east to east-central Veracruz.

OpenStreetMap – Google Earth. Retrieved 5 June Males had relatively larger heads, and differed from females in head shape after removing the effects of head size. Frequently found in rocky terrain. In the present study, we describe variation and sexual dimorphism of head form i. By using this site, you oolystictus to the Terms of Use and Privacy Policy.


Envenomation by the Mexican lance-headed rattlesnake Crotalus polystictus: a case report.

Dimorphism in head size or shape may result from non-adaptive processes e. Can you confirm these amateur observations of Crotalus polystictus? In addition to separating components of size and shape, geometric morphometrics GM is advantageous in that the use of landmark and outline coordinates allows a visually intuitive projection of results back into the organismal morphospace.

Finally, we tested for allometry in head shape for males and females separately by using Pearson correlation to test the null hypothesis of no relationship between head shape PC1 scores and head size CS. Strong, but incomplete, mate choice discrimination between two closely related species of paper wasp. Other Shock secondary to fluid shifts due to local tissue injury is likely in severe cases. Interestingly, other than C. This manuscript was improved by comments from J.

BMC Evolutionary Biology9: The differences in diet correspond with dimorphism in head morphology, and provide evidence of intersexual niche divergence in the study population. Sexual dimorphism in head shape and diet in the cottonmouth snake Agkistrodon piscivorus. Although diet differences in the study population of C.

Although voles were the most important mass-weighted element in the diets of both males and females Cgotalus polystictus Mexican Lance-headed Rattlesnake Diet. Generalized Procrustes analysis GPA was used to superimpose landmarks onto a common coordinate system and to remove effects of location, orientation, and scale.