A Survey of the Herpetofauna of the Comanche National Grasslands in Southeastern Colorado
Appendix 6
Presentations, Master's Theses and Honors Student Thesis
Presentations:
Presented at the 1996 annual meeting of the Society for the Study of Amphibians and Reptiles (SSAR) in Lawrence, KansasAbstract 134 HOBERT, JUSTIN; MACKESSY, STEPHEN P.
Department of Biological Sciences, University of Northern Colorado, Greeley, CO 80639
Distribution and morphological variation of the massasauga rattlesnake (Sistrurus catenatus) in southeastern Colorado
The massasauga rattlesnake (Sistrurus catenatus) is currently considered a species of special concern by the Colorado Division of Wildlife. From July 1994 to October 1995, we captured live or collected dead massasaugas from southeastern Colorado; live snakes were measured, PIT-tagged and released. Scale counts on 18 areas of the body were examined for 91 specimens. These characteristics, along with ground color and average adult length, were used to evaluate the taxonomic status of the massasauga in Colorado. Distribution results indicate that the population of massasaugas in Colorado is disjunct from the neighboring populations. Undisturbed short-grass prairie, an increasingly uncommon habitat, is the dominant habitat type associated with massasauga locations in Colorado. Specific scale counts show that the Colorado population is more closely related to the desert massasauga (S. c. edwardsii) than it is to the western massasauga (S. c. tergeminus). Of the Colorado massasaugas examined, 95% have 23 scale rows at midbody [an edwardsii character], and 90% show gray to dark gray ground color; average length is 365 mm. The morphometric and habitat data support the conclusion that massasaugas in Colorado should be designated as the desert subspecies, S. c. edwardsii, not as an intergrade. This work was supported by a CDOW grant to SPM.
Abstract 65 MONTGOMERY, CHAD; WALDRON, KEVIN; MACKESSY, STEPHEN P.
Department of Biological Sciences, University of Northern Colorado, Greeley, CO 80639
Notes on the natural history of the Texas horned lizard, Phrynosoma cornutum, in southeastern Colorado
The Texas horned lizard, Phrynosoma cornutum, is currently listed as a species of special concern by the Colorado Division of Wildlife. An initial field study of the natural history of the Texas horned lizard was conducted from June 15 to September 15, 1995 in short-grass prairie and agricultural land in SE Colorado. The study included observations on the size, gender ratio, escape and defense behavior, predation, distribution, habitat, activity period, movement, gut content and intestinal parasite load. Live specimens were PIT-tagged and released at the site of capture, and roadkilled specimens were collected and preserved. Of the 60 horned lizards found in this period, 36 were alive and 24 were dead. Nine roadkilled specimens were used in gut content and parasite studies. Two species of ants were the primary prey, and no helminth parasites were noted. The results of this study showed that while P. cornutum are not abundant in SE Colorado, they are locally abundant in areas with suitable habitat (i.e., undisturbed prairie with open sandy soils). In general, the natural history of the Texas horned lizard in southeastern Colorado is similar to the reported natural history of Phrynosoma cornutum throughout its entire range. This work was supported by a CDOW grant to SPM.
Abstract 133 MACKESSY, STEPHEN P.; MUNEKIYO, SEAN M.
Department of Biological Sciences, University of Northern Colorado, Greeley, CO 80639
Venom characteristics as indicators of subspecies affiliation in the massasauga rattlesnake (Sistrurus catenatus)
Composition of snake venoms is affected by numerous factors, making the utility of venoms as a reliable source of markers in population genetics studies somewhat questionable. However, certain venom characteristics may be useful as indicators of population affinities. Venoms from the three subspecies of the massasauga rattlesnake, Sistrurus catenatus, were obtained from snakes at several locations and compared with venoms from Colorado massasaugas, a disjunct population typically considered an intergrade population (S. c. tergeminus and S.c. edwardsii). Analyses of venoms included assays for several common and important enzymes, molecular fingerprinting via SDS-PAGE and electrophoretic assays for metalloproteases. Based on enzymatic and electrophoretic characteristics, the Colorado snakes show a greater similarity to the desert massasauga subspecies than to neighboring populations to the east, and intergradation, if occurring, is minimal. These results suggest that the Colorado population should be considered S. c. edwardsii and that the closest related populations currently exist in New Mexico, not Kansas.
Abstract 72 HILL, ROBERT E.; MACKESSY, STEPHEN P.
Department of Biological Sciences, University of Northern Colorado, Greeley, CO 80639
Venom yields from several species of colubrid snakes and differential effects of ketamine
The composition of rear-fanged colubrid snake venoms are largely unknown due to the difficulty involved in venom collection. Several different methods have been used to maximize the yield of Duvernoy's secretions. The method of Rosenberg (1992) was used in the present study to collect the Duvernoy's secretions from eight species of colubrids. Protein concentrations were determined for the venoms collected to distinguish Duvernoy's secretions from saliva (primarily mucopolysaccharides). Average protein concentrations for venoms ranged from 49.8-96.4%; most yields obtained from specimens in this study were significantly greater than yields previously reported. There was a wide range of effects that occurred due to the ketamine anesthesia. These effects ranged from no apparent discomfort in some specimens to violent thrashing in others; all snakes recovered from the effects of the ketamine hydrochloride with no apparent ill effects. Doses of ketamine hydrochloride have thus been adjusted, depending on species and previous reactions to the drug. The use of ketamine/ pilocarpine in the collection of Duvernoy's secretion collection has proven to be highly effective in increasing yields. Some caution should be observed when administering ketamine to various species of colubrids, as effects do not necessarily scale to body mass.
Other Presentations
1. Stephen P. Mackessy: Amphibians and Reptiles of Southeastern Colorado. Denver Museum of Natural History Zoology Department, 2 December 1997.
2. Chad Montgomery: Amphibians and Reptiles of Southeastern Colorado. Hugo Audubon Society, March 1998.
Master's Theses at the University of Northern Colorado, Department of Biological Sciences:
1. Justin Hobert: Ecology, Natural History and Taxonomic Status of the Massasauga (Sistrurus catenatus) in Colorado. Awarded August 1997.
2. Chad Montgomery: A Natural History Study of the Texas Horned Lizard (Phrynosoma cornutum) in Southeastern Colorado and An Analysis of Clinal Variation Throughout Its Range. Spring 1998.
Honors Thesis at the University of Northern Colorado, Department of Biological Sciences:
1. Theresa Childers: Effects of the non-native bullfrog (Rana catesbeiana) on native species in southeastern Colorado. To be completed Spring 1999.
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