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José M De Jesús-escobar - One of the best experts on this subject based on the ideXlab platform.
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Molecular Systematics of New World Gopher, Bull, and Pinesnakes (Pituophis: Colubridae), a Transcontinental Species Complex
Molecular phylogenetics and evolution, 2000Co-Authors: Javier A. Rodríguez-robles, José M De Jesús-escobarAbstract:Pituophis melanoleucus (gopher, bull, and pinesnakes) is among the most widely distributed polytypic species complexes in North America, with most authors recognizing from a single transcontinental species (the melanoleucus complex, composed of 15 subspecies) to four (monotypic and polytypic) species. We used mitochondrial gene sequences from the two middle American species, P. deppei and P. lineaticollis, and from 13 subspecies from most of the range of the melanoleucus complex to test various phylogenetic hypotheses for Pituophis. Maximum parsimony and maximum likelihood methods identified the same major clades within Pituophis and indicated that two segments of the melanoleucus complex, the lodingi-melanoleucus-mugitus eastern pinesnake clade and the affinis-annectens-bimaris-catenifer-deserticola- sayi-ruthveni-vertebr alis clade from central and western United States and northern Mexico, represent divergent, allopatric lineages with no known intergradation zone. We recognize each of these two groupings as a different species. Our data also indicate that some ruthveni are more closely related to sayi than to other ruthveni. Nonetheless, ruthveni is an allopatric taxon diagnosable from its closest relatives by a combination of morphometric characters, and because it is likely that at least some of these traits are independent and genetically inherited, we interpret this as evidence that ruthveni has attained the status of independent evolutionary lineage, despite the fact that it retains strong genetic affinities with sayi. The endemic Baja Californian gopher snakes (bimaris and vertebralis) are considered by some taxonomists as a different species, P. vertebralis, but we discovered that these serpents belong to two different clades and hence we do not agree with the recognition of P. vertebralis as presently defined. In summary, we believe that three distinct species are included in the melanoleucus complex, Pituophis melanoleucus (sensu stricto), P. catenifer, and P. ruthveni, and that their recognition better represents the evolutionary diversity within this species complex.
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Regular ArticleMolecular systematics of New World lampropeltinine snakes (Colubridae): implications for biogeography and evolution of food habits
Biological Journal of the Linnean Society, 1999Co-Authors: Javier A. Rodríguez-robles, José M De Jesús-escobarAbstract:We used mitochondrial gene sequences to infer phylogenetic relationships among North American snakes of the colubrid tribe Lampropeltini (Arizona, Bogertophis, Cemophora, New World Elaphe,Lampropeltis , Pituophis, Rhinocheilus, Senticolis, Stilosoma), and assessed the implications of our findings for the biogeography and evolution of food habits among these serpents. The maximum likelihood phylogeny identified Rhinocheilus as the sister taxon to all other lampropeltinines, and supported the monophyly ofLampropeltis (including Stilosoma), New World Elaphe, and Pituophis, but not that ofBogertophis . This phylogeny also suggested a sister group relationship between Cemophora andLampropeltis , and between New World Elaphe and Pituophis, and strongly supported thatSenticolis belongs within Lampropeltini, thus contradicting previous suggestions that Senticolis is not a lampropeltinine. Using a method for approximating ancestral areas of clades, we determined that western North America was most likely the ancestral area of lampropeltinines. Our survey of published studies, combined with unpublished data, indicated that lampropeltinines as a group feed mainly on mammals, less frequently on lizards, birds, and bird eggs, and only rarely on squamate eggs, snakes, anurans, and insects. Some individual species indeed emphasize mammals in their diets, but others most frequently eat lizards, squamate eggs, bird eggs, or snakes, whereas others take two prey types with similar frequency. Our reconstruction of the evolution of food habits among lampropeltinines suggests that a diet emphasizing lizards is ancestral, and therefore diets that mostly consist of mammals, squamate and bird eggs, and snakes are derived within the clade. In at least some species, smaller individuals prey mostly on lizards and larger ones add mammals to their diets.
Javier A. Rodríguez-robles - One of the best experts on this subject based on the ideXlab platform.
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Home Ranges of Gopher Snakes (Pituophis catenifer, Colubridae) in Central California
Copeia, 2003Co-Authors: Javier A. Rodríguez-roblesAbstract:Abstract Knowledge of the home range of an animal can provide insights for studies of behavioral interactions among individuals, and long-term monitoring of particular animals is necessary to determine whether they exhibit seasonal variation in space-use patterns. I radio-tracked four adult male Pituophis catenifer (gopher snake) in central California for 14 consecutive months to investigate spatial and seasonal movement patterns. Using the fixed kernel density estimator to produce a probability contour, the 95% home ranges of P. catenifer ranged from 0.89–1.78 ha, whereas their core areas (50% polygons), the most heavily used areas of their home ranges, ranged from 0.1–0.29 ha. Movements of male P. catenifer were similar in spring and summer and decreased in autumn and winter. The telemetered snakes were close to marshes and Eucalyptus woodlands but were routinely found in grassland areas, perhaps because this habitat type may provide abundant food resources and partial protection from predators. Despite...
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Feeding ecology of North American gopher snakes (Pituophis catenifer, Colubridae)
Biological Journal of the Linnean Society, 2002Co-Authors: Javier A. Rodríguez-roblesAbstract:Studies of food relations are important to our understanding of ecology at the individual, population and community levels. Detailed documentation of the diet of large-bodied, widespread snakes allows us to assess size-dependent and geographical variation in feeding preferences of gape-limited predators. Furthermore, with knowledge of the food habits of sympatric taxa we can explore possible causes of interspecific differences in trophic niches. The feeding ecology of the North American gopher snake, Pituophis catenifer, was studied based on the stomach contents of more than 2600 preserved and free-ranging specimens, and published and unpublished dietary records. Of 1066 items, mammals (797, 74.8%), birds (86, 8.1%), bird eggs (127, 11.9%), and lizards (35, 3.3%) were the most frequently eaten prey. Gopher snakes fed upon subterranean, nocturnal and diurnal prey. The serpents are primarily diurnal, but can also be active at night. Therefore, gopher snakes captured their victims by actively searching underground tunnel systems, retreat places and perching sites during the day, or by pursuing them or seizing them while they rested at night. Gopher snakes of all sizes preyed on mammals, but only individuals larger than 40 and 42 cm in snout–vent length took bird eggs and birds, respectively, possibly due to gape constraints in smaller serpents. Specimens that ate lizards were smaller than those that consumed mammals or birds. Gopher snakes raided nests regularly, as evidenced by the high frequency of nestling mammals and birds and avian eggs eaten. Most (332) P. catenifer contained single prey, but 95 animals contained 2–35 items. Of the 321 items for which direction of ingestion was determined, 284 (88.5%) were swallowed head-first, 35 (10.9%) were ingested tail-first, and two (0.6%) were taken sideways. Heavier gopher snakes took heavier prey, but heavier serpents ingested prey with smaller mass relative to snake mass, evidence that the lower limit of prey mass did not increase with snake mass. Specimens from the California Province and Arid Deserts (i.e. Mojave, Sonoran and Chihuahuan Deserts) took the largest proportion of lizards, whereas individuals from the Great Basin Desert consumed a higher percentage of mammals than serpents from other areas, and P. catenifer from the Great Plains ate a greater proportion of bird eggs. Differences in prey availability among biogeographical regions and unusual circumstances of particular gopher snake populations may account for these patterns. Gopher snakes have proportionally longer heads than broadly sympatric Rhinocheilus lecontei (long-nosed snake), Charina bottae (rubber boa) and Lampropeltis zonata (California mountain kingsnake), which perhaps explains why, contrary to the case in P. catenifer, the smaller size classes of those three species do not eat mammals. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 77, 165–183.
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Molecular Systematics of New World Gopher, Bull, and Pinesnakes (Pituophis: Colubridae), a Transcontinental Species Complex
Molecular phylogenetics and evolution, 2000Co-Authors: Javier A. Rodríguez-robles, José M De Jesús-escobarAbstract:Pituophis melanoleucus (gopher, bull, and pinesnakes) is among the most widely distributed polytypic species complexes in North America, with most authors recognizing from a single transcontinental species (the melanoleucus complex, composed of 15 subspecies) to four (monotypic and polytypic) species. We used mitochondrial gene sequences from the two middle American species, P. deppei and P. lineaticollis, and from 13 subspecies from most of the range of the melanoleucus complex to test various phylogenetic hypotheses for Pituophis. Maximum parsimony and maximum likelihood methods identified the same major clades within Pituophis and indicated that two segments of the melanoleucus complex, the lodingi-melanoleucus-mugitus eastern pinesnake clade and the affinis-annectens-bimaris-catenifer-deserticola- sayi-ruthveni-vertebr alis clade from central and western United States and northern Mexico, represent divergent, allopatric lineages with no known intergradation zone. We recognize each of these two groupings as a different species. Our data also indicate that some ruthveni are more closely related to sayi than to other ruthveni. Nonetheless, ruthveni is an allopatric taxon diagnosable from its closest relatives by a combination of morphometric characters, and because it is likely that at least some of these traits are independent and genetically inherited, we interpret this as evidence that ruthveni has attained the status of independent evolutionary lineage, despite the fact that it retains strong genetic affinities with sayi. The endemic Baja Californian gopher snakes (bimaris and vertebralis) are considered by some taxonomists as a different species, P. vertebralis, but we discovered that these serpents belong to two different clades and hence we do not agree with the recognition of P. vertebralis as presently defined. In summary, we believe that three distinct species are included in the melanoleucus complex, Pituophis melanoleucus (sensu stricto), P. catenifer, and P. ruthveni, and that their recognition better represents the evolutionary diversity within this species complex.
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Regular ArticleMolecular systematics of New World lampropeltinine snakes (Colubridae): implications for biogeography and evolution of food habits
Biological Journal of the Linnean Society, 1999Co-Authors: Javier A. Rodríguez-robles, José M De Jesús-escobarAbstract:We used mitochondrial gene sequences to infer phylogenetic relationships among North American snakes of the colubrid tribe Lampropeltini (Arizona, Bogertophis, Cemophora, New World Elaphe,Lampropeltis , Pituophis, Rhinocheilus, Senticolis, Stilosoma), and assessed the implications of our findings for the biogeography and evolution of food habits among these serpents. The maximum likelihood phylogeny identified Rhinocheilus as the sister taxon to all other lampropeltinines, and supported the monophyly ofLampropeltis (including Stilosoma), New World Elaphe, and Pituophis, but not that ofBogertophis . This phylogeny also suggested a sister group relationship between Cemophora andLampropeltis , and between New World Elaphe and Pituophis, and strongly supported thatSenticolis belongs within Lampropeltini, thus contradicting previous suggestions that Senticolis is not a lampropeltinine. Using a method for approximating ancestral areas of clades, we determined that western North America was most likely the ancestral area of lampropeltinines. Our survey of published studies, combined with unpublished data, indicated that lampropeltinines as a group feed mainly on mammals, less frequently on lizards, birds, and bird eggs, and only rarely on squamate eggs, snakes, anurans, and insects. Some individual species indeed emphasize mammals in their diets, but others most frequently eat lizards, squamate eggs, bird eggs, or snakes, whereas others take two prey types with similar frequency. Our reconstruction of the evolution of food habits among lampropeltinines suggests that a diet emphasizing lizards is ancestral, and therefore diets that mostly consist of mammals, squamate and bird eggs, and snakes are derived within the clade. In at least some species, smaller individuals prey mostly on lizards and larger ones add mammals to their diets.
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Alternative Perspectives on the Diet of Gopher Snakes (Pituophis catenifer, Colubridae): Literature Records versus Stomach Contents of Wild and Museum Specimens
Copeia, 1998Co-Authors: Javier A. Rodríguez-roblesAbstract:In addition to supplementing investigations on the trophic niche of a predator, published dietary records can provide essential information to address patterns of geographic, ontogenetic, and historical variation in an animal's feeding habits (e.g., Greene, 1989; King 1993; Slowinski, 1994). During a study of the feeding ecology of gopher snakes, Pituophis catenifer, I noticed that the frequencies of prey types recovered from wild and preserved specimens seemed to differ from those gathered from published accounts of the diet of this snake. Thus, herein I quantitatively examine those differences and discuss their implications for studies of feeding ecology. The number of species within the genus Pituophis in the United States has been a controversial issue for several decades (e.g., Smith and Kennedy, 1951; Conant, 1956; Reichling, 1995). Phylogenetic analyses of mitochondrial DNA sequences of specimens across the country (J. A. Rodriguez-Robles and J. M. De Jesis-Escobar, unpubl. data) support previous suggestions (e.g., Fugler, 1955; Wright and Wright, 1957) that Pituophis snakes in the United States belong to at least two species: P. catenifer, in the central and western parts of the country, and P melanoleucus (sensu stricto) in the eastern United States (see Sweet and Parker, 1990), a taxonomic arrangement that I follow herein.
Jose M De Jesusescobar - One of the best experts on this subject based on the ideXlab platform.
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molecular systematics of new world lampropeltinine snakes colubridae implications for biogeography and evolution of food habits
Biological Journal of The Linnean Society, 1999Co-Authors: Javier A Rodriguezrobles, Jose M De JesusescobarAbstract:Abstract We used mitochondrial gene sequences to infer phylogenetic relationships among North American snakes of the colubrid tribe Lampropeltini ( Arizona , Bogertophis , Cemophora , New World Elaphe , Lampropeltis , Pituophis , Rhinocheilus , Senticolis , Stilosoma ), and assessed the implications of our findings for the biogeography and evolution of food habits among these serpents. The maximum likelihood phylogeny identified Rhinocheilus as the sister taxon to all other lampropeltinines, and supported the monophyly of Lampropeltis (including Stilosoma ), New World Elaphe , and Pituophis , but not that of Bogertophis . This phylogeny also suggested a sister group relationship between Cemophora and Lampropeltis , and between New World Elaphe and Pituophis , and strongly supported that Senticolis belongs within Lampropeltini, thus contradicting previous suggestions that Senticolis is not a lampropeltinine. Using a method for approximating ancestral areas of clades, we determined that western North America was most likely the ancestral area of lampropeltinines. Our survey of published studies, combined with unpublished data, indicated that lampropeltinines as a group feed mainly on mammals, less frequently on lizards, birds, and bird eggs, and only rarely on squamate eggs, snakes, anurans, and insects. Some individual species indeed emphasize mammals in their diets, but others most frequently eat lizards, squamate eggs, bird eggs, or snakes, whereas others take two prey types with similar frequency. Our reconstruction of the evolution of food habits among lampropeltinines suggests that a diet emphasizing lizards is ancestral, and therefore diets that mostly consist of mammals, squamate and bird eggs, and snakes are derived within the clade. In at least some species, smaller individuals prey mostly on lizards and larger ones add mammals to their diets.
Joanna Burger - One of the best experts on this subject based on the ideXlab platform.
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Hibernation Site Philopatry in Northern Pine Snakes (Pituophis melanoleucus) in New Jersey
Journal of herpetology, 2015Co-Authors: Joanna Burger, Robert T. ZappalortiAbstract:Northern Pine Snakes (Pituophis melanoleucus) are one of the few snakes that spend the winter in underground hibernacula that they excavate. We report the use of hibernacula by Pine Snakes from 1986 to 2012 in the New Jersey Pine Barrens. We determined whether philopatry to a specific hibernaculum varied as a function of age, sex, and location of the hibernaculum. Three hibernacula were occupied nearly continuously for 27 yr by 1 to 27 snakes each year. With known-age snakes (N = 120), captured mainly as hatchlings and 2-yr-olds, we found that 23% were always philopatric. Philopatry was related to age of last capture, sex, and capture location. Philopatry was higher for 1) females compared with males, 2) snakes at two solitary hibernacula compared with a hibernaculum complex, and 3) snakes 6 yr old or younger, compared with older snakes. Of hatchlings found hibernating, 24% used the same hibernation site the next year, and 38% were located at year 4 or later. The number of snakes that always used the same hibernation site declined with the age of last capture. Snakes that entered hibernacula as hatchlings were found more often than those that entered as 2-yr-olds. For the seven snakes that were 14 yr or older, females were found 64- 86 % of the time, whereas males were found 15 to 50% of the time. Understanding the behavior and habitat requirements of snakes during different seasons is central to life-history analysis and for conserving viable populations.
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Long-Term Use of Hibernacula by Northern Pinesnakes (Pituophis melanoleucus)
Journal of Herpetology, 2012Co-Authors: Joanna Burger, Michael Gochfeld, Robert T. Z Appalorti, Emile Devito, David W. Schneider, Matt Mccort, Christian JeitnerAbstract:Abstract Understanding the specific habitat requirements of reptiles during different life stages or seasons is critical to conserving viable populations. Northern Pinesnakes (Pituophis melanoleucus) are one of the few species that spend the winter in underground hibernacula, which they excavate themselves. We report on 26 years (1986–2011) of monitoring Pinesnake use at seven hibernacula in the New Jersey Pine Barrens. Our goal was to determine the frequency of repeated use, number of snakes present by year, disruptions of hibernacula, and the relationship between number of snakes present and the probability of occupancy of each hibernaculum in successive years. The overall goal was to determine the importance of protecting known hibernation sites regardless of whether they appear occupied in a given season. These data suggest that, if no snakes are observed entering a particular hibernaculum over a limited time period, it does not mean none are there or that none will use it in successive years. The var...
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for survival
2007Co-Authors: Joanna BurgerAbstract:The behavioral response of emerging pine snakes (Pituophis melanoleucus) to people: implication
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Trace element levels in pine snake hatchlings: Tissue and temporal differences
Archives of Environmental Contamination and Toxicology, 1992Co-Authors: Joanna BurgerAbstract:Trace element levels have seldom been examined in reptiles, although some large snakes are high on the trophic level pyramid. Lead, cadmium, mercury, selenium, chromium and manganese levels were examined in skin and whole body tissue of pine snakes ( Pituophis melanoleucus ) from the New Jersey Pine Barrens between 1985–1990. Depending on the element, variations in levels were primarily explained by year and tissue, and not by sex or location. There were significantly higher levels of lead, mercury, and chromium in the skin compared to the whole body tissue, suggesting that the frequent shedding of skin can act as a method of toxic metal excretion by snakes. Manganese and selenium levels were significantly higher in the body compared to the skin.
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Response to prey chemical cues by hatchling pine snakes (Pituophis melanoleucus): Effects of incubation temperature and experience
Journal of Chemical Ecology, 1991Co-Authors: Joanna BurgerAbstract:The ability of hatchling pine snakes ( Pituophis melanoleucus ) to select and follow or avoid chemical odors of prey (mice, Mus musculus) on a shavings and paper substrate was investigated in Y-maze experiments, as a function of incubation temperature and experience. Incubation temperature affected behavior in the maze, and the maze choices of naive snakes, but not of snakes that had already eaten a mouse. The data indicate that snakes that have eaten, preferentially enter the arm bearing chemical stimuli from mice, whereas those that have not eaten show no preference.
Javier A Rodriguezrobles - One of the best experts on this subject based on the ideXlab platform.
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molecular systematics of new world lampropeltinine snakes colubridae implications for biogeography and evolution of food habits
Biological Journal of The Linnean Society, 1999Co-Authors: Javier A Rodriguezrobles, Jose M De JesusescobarAbstract:Abstract We used mitochondrial gene sequences to infer phylogenetic relationships among North American snakes of the colubrid tribe Lampropeltini ( Arizona , Bogertophis , Cemophora , New World Elaphe , Lampropeltis , Pituophis , Rhinocheilus , Senticolis , Stilosoma ), and assessed the implications of our findings for the biogeography and evolution of food habits among these serpents. The maximum likelihood phylogeny identified Rhinocheilus as the sister taxon to all other lampropeltinines, and supported the monophyly of Lampropeltis (including Stilosoma ), New World Elaphe , and Pituophis , but not that of Bogertophis . This phylogeny also suggested a sister group relationship between Cemophora and Lampropeltis , and between New World Elaphe and Pituophis , and strongly supported that Senticolis belongs within Lampropeltini, thus contradicting previous suggestions that Senticolis is not a lampropeltinine. Using a method for approximating ancestral areas of clades, we determined that western North America was most likely the ancestral area of lampropeltinines. Our survey of published studies, combined with unpublished data, indicated that lampropeltinines as a group feed mainly on mammals, less frequently on lizards, birds, and bird eggs, and only rarely on squamate eggs, snakes, anurans, and insects. Some individual species indeed emphasize mammals in their diets, but others most frequently eat lizards, squamate eggs, bird eggs, or snakes, whereas others take two prey types with similar frequency. Our reconstruction of the evolution of food habits among lampropeltinines suggests that a diet emphasizing lizards is ancestral, and therefore diets that mostly consist of mammals, squamate and bird eggs, and snakes are derived within the clade. In at least some species, smaller individuals prey mostly on lizards and larger ones add mammals to their diets.