Showing papers in "Herpetologica in 1984"

Male breeding success and differential access to females in anolis carolinensis

Abstract: Current models of polygynous mating systems predict greater variance in repro- ductive success among males than among females. The sources of variation of breeding success remain poorly known. A population of the lizard Anolis carolinensis was studied to determine the variance in breeding success among males as measured by sightings of matings and ability to control areas that overlap females during a prolonged breeding season. Males seen mating were larger, heavier, and observed more often than males not seen mating. Estimates of the number of females overlapped by individual males also supported the hypothesis that larger males have greater mating success than smaller males. Effects of patterns of receptivity and female choice upon the mating system of A. carolinensis are discussud.

The relationship between lizard home range and body size: a reanalysis of the data

Abstract: We reanalyzed the relationship between home range and lizard body size. Our analysis includes home ranges estimated with the convex polygon technique and a recently proposed method for eliminating sample size bias. When analyzed separately, neither insectivorous, carnivorous nor female herbivorous lizards had a significant regression of home range size against body mass; male herbivores had a marginally significant regression. Combining data for the different foraging types resulted in significant regressions for both males and females; the regression for the pooled data set (males plus females) was also significant. Our regression equations differ significantly from previously published equations derived from home range estimates adjusted for sample size bias. Except for the intercepts of the female regressions, our equations do not differ significantly from earlier equations derived from unadjusted home range estimates. Our analysis showed that home range size for the side-blotched lizard, Uta stansburiana, could be accurately determined, without sample size bias, with an average of 13 resightings per lizard.

Molecular systematics of neotropical xenodontine snakes. II: Central American xenodontines

Abstract: Molecular evidence comprising microcomplement fixation comparisons of albumins is used to analyze the phylogenetic relationships of genera within a large group of Central American xenodontines. This group was previously shown to be monophyletic relative to other taxa of xenodontines and is one of two major lineages within the radiation. Based on reciprocal immunological comparisons among the albumins of Coniophanes, Geophis, Sibon, Ninia, Leptodeira and Eridiphas, the following clades are recognized: (1) Leptodeira-Eridiphas and (2) Geophis-Ninia-dipsadines. Coniophanes shares a common lineage with the latter. Hypsiglena and Leptodeira latifasciata share a lineage with Eridiphas. Cryophis belongs to the Leptodeira-Eridiphas clade but is close to none of the species for which antisera are available. Atractus, Amastridium, Chersodromus and Adelphicos are members of the Central American xenodontine clade, but they do not appear to be closely related to reference species within it for which antisera were available. Four genera of dipsadines are all close to Sibon. The genus Rhadinaea is shown to be polyphyletic. Two members of the R. brevirostris group examined belong to the South American xenodontine radiation, and their average immunological distance from Central American xenodontines is greater than 70. The other species of Rhadinaea examined, as well as Pliocercus, are close to Coniophanes. The molecular data suggest, however, that Central American Rhadinaea may be paraphyletic relative to other genera in that lineage.

Ontogenetic changes in vulnerability to predation in tadpoles of Hyla pseudopuma

Abstract: Etude de la predation exercee sur les tetards de H.p. en fonction de leur âge par des coleopteres aquatiques ou des odorates

The importance of caudal lipid in the gecko phyllodactylus marmoratus

Abstract: The nutritive function of caudal lipid in the lizard Phyllodactylus marmoratus was investigated. Starved geckos possessing tails lived significantly longer than starved tailless geckos at 10 C. Starved or cold geckos retained their tails longer than well-fed or warm geckos when subjected to pressure to autotomise. Adults, which possessed relatively more tail lipid than juveniles, also resisted autotomy pressure longer. Geckos under suboptimal conditions tend to retain their tails, preserving the caudal lipid so important for survival.

Winter temperatures of chrysemys picta nests in michigan: effects on hatchling survival

Abstract: Winter temperatures of the nests of Chrysemys picta were rarely below -2.0 C, although one nest reached -3.3 C. There was no significant difference between nest and soil temperatures at the same depth, indicating the absence of observable metabolic heat production by hatchlings. Two nests were excavated in February. The hatchlings were responsive to touch and symmetrically arranged in the nest with their heads directed upwards. Snow cover is an important insulator of soil. Data of hatchling survivorship over 5 yr suggests winter-kill may be an important source of hatchling mortality during winters with little snow cover. No hatchlings died during a winter (1981-1982) characterized by deep snow cover.

Diet, digestion, and food preferences of Galapagos land iguanas

Abstract: The choice of food types and the length of time food passed through the gastrointestinal tract were determined in free-ranging Conolophus pallidus on Isla Santa Fe, Galapogos throughout the year. Natural foods were analyzed for energy, percent cellulose, percent nitrogen, and calcium as indices of the quality of food. Foods of highest quality were found to be among the preferred foods, but not all preferred foods were of high quality with respect to the nutrients measured. Passage time of food through the gastrointestinal tract, digestive efficiency, and digestion of cellulose were determined on captive Conolophus subcristatus. Ability to digest cellulose and digestive efficiency varied among five caged iguanas. Intra- and interspecific variabilities in digestive capacities result from variability in ecological factors, and interspecific variability among iguanines probably reflects differences in colic anatomy and the ability to absorb nutrients from the hindgut. 23 references, 4 tables.

Reproductive behavior and aerobic capacities of male american toads (bufo americanus): is behavior constrained by physiology?

Abstract: We tested the hypothesis that individual differences in calling and searching be- havior by males in a chorus of Bufo americanus were correlated with differences in aerobic capacity. Fifteen observers made focal animal observations of male behavior on the peak night of breeding activity, followed by replicate measurements of aerobic capacity during forced exercise for each animal. The toads exhibited significant variation among individuals in amount of calling, amount of movement, and number of clasping attempts. Males also differed in aerobic capacity, with nearly 90% of the total variance in a repeated measures analysis explained by differences among individuals. However, aerobic capacity was not correlated with any behavioral variable, and there was no relationship between behavioral or physiological measurements and male body size. Our results do not support the hypothesis that differences in the behavior of males in a chorus are due to differences in their physiological capacities to use energy.

Thermal biology of the live bearing lizard Gerrhonotus coeruleus

Abstract: I measured cloacal temperatures of both male and female Gerrhonotus coeruleus from two populations along the coast of California (Monterey and Mendocino counties) throughout the season when females are reproductively active (May-August). Mean body temperature for all females (x = 25.3 C; SE = 0.4) was significantly higher (P < 0.05) than mean male body temperature (x = 24.0 C; SE = 0.5) and variance in mean body temperature was significantly lower (F... 1.37, P < 0.05) for females (s2= 12.66) compared to males (s2= 17.36). Males in the Mendocino County population experienced higher mortality than females for the only year (1974-1975) for which data are available. I propose a model for the evolution of viviparity in egg-retaining species of lizards in which secretive behavior of thigmothermic females reduces reproductive risk during gestation.

Opportunistic behavioral thermoregulation of turtles, Pseudemys scripta, in response to microclimatology of a nuclear reactor cooling reservoir

Abstract: Thermal effluents raised water temperature in one arm of a nuclear reactor cooling reservoir as much as 9 C but had little or no effect on temperature of other areas, or on shoreline microclimate. Pseudemys scripta used an opportunistic strategy of thermoregulation. None resided near the point of thermal discharge. Turtles in heated areas underwent aquatic basking. Body temperatures telemetered from unrestrained turtles were within the preferred temperature range and indicated that aquatic basking raised body temperature 1-3 C above water temperature. In normothermic portions of the reservoir, turtles underwent atmospheric basking on sunny days throughout the year. In summer, basking frequency during the day showed a bimodal curve. Thermoregulatory strategies of these turtles and other turtles from diverse ecological habitats and geographic areas are discussed.

Species specificity of sex pheromone trails in the plains garter snake, Tchamnophis radix

Abstract: The ability of male plains garter snakes to discriminate sex pheromone trails was tested using a Y-maze. Thamnophis radix radix from Illinois and T. radix haydeni from Colorado both preferred their own females' trails or trails of the closely related, primarily allopatric T. marcianus over a blank arm. Yet both subspecies preferred their own females' trails over T. marcianus trails. Neither subspecies significantly trailed the more distantly related, sympatric T. sirtalis. The species specificity of these trails may be involved in the reproductive isolation of the sympatric T. sirtalis and T. radix. Thamnophis radix and T. marcianus are more closely related and they apparently have similar but still distinguishable pheromone trails. One explanation for the occurrence of pheromone specificity in these two allopatric Thamnophis would be that in the recent past T. radix and T. marcianus were sympatric. This hypothesis is consistent with current knowledge concerning the evolution of these species.

The pseudohemisus tadpole: a morphological link between microhylid (orton type 2) and ranoid (orton type 4) larvae

Abstract: Pseudohemisus is an endemic Malagasy frog genus that has been placed by some systematists within the family Ranidae and by others in the Microhylidae. Blommers-Schlosser (1975) described the Pseudohemisus granulosus tadpole and reported that it had a mosaic of ranid (e.g., sinistral spiracle) and microhylid (e.g., hard mouthparts absent) features. I have reexamined these larvae to see if additional characters could help determine whether Pseudohemisus is a ranid or a microhylid. Scanning electron microscopy revealed that the P. granulosus tadpole does, in fact, have keratinized mouthparts, like ranids. However, it also has several strictly microhylid features and-in overall agreement with Blommers-Schlosser (1975)-many features that are in- termediate between the two families (e.g., structure and shape of branchial food traps; position of the glottis; shape of the ventral velum). Unexpectedly, the P. granulosus larva resembles certain direct-developing frog embryos, where evolution has recently truncated normal tadpole development. This suggests that the microhylid tadpole (Orton type 2) may have evolved from a ranoid-like (Orton type 4) larva through trun- cation of the normal type 4 developmental program. Based on the P. granulosus tadpole, there can be no doubt that the Ranoidea and Microhyloidea are closely related taxa.

Defensive behavior of brooding female red-backed salamanders (Plethodon cinereus)

Abstract: Quantitative information is presented on defensive behavior of brooding female Plethodon cinereus. Responses of females to brooding and non-brooding conspecifics and snakes were observed in the laboratory. Aggressive defense was exhibited by 91% of attendants and 5% of intruders in encounters between brooding females. Attendants were equally aggressive in encounters with non-brooding intruders (85% for adults and juveniles) and less with hatchlings (44%) none of which showed aggressive behavior. Responses of attendants to intrusion indicate that they may be defending the nest cavity as well as the eggs and therefore are exhibiting both territorial behavior and parental care.

Antipredator adaptations of Asian salamanders (Salamandridae)

Abstract: Antipredator adaptations previously undescribed in this family are described for Tylototriton, Echinotriton, Mertensiella and Paramesotriton. Tylototriton verrucosus has concentrations of enlarged granular glands located in many regions (corresponding closely to the distribution of orange pigmentation on the dorsal surface). It has defensive postures to display each of these glandular regions to predators and elongated blunt ribs that are used to elevate the lateral warts. Echinotriton andersoni has a similar distribution of enlarged granular glands, but it exhibits a stereotyped rigid antipredator posture. It also has elongated, sharp ribs with sharp epipleural processes. These pierce through the lateral warts which are concentrations of enlarged granular glands. Echinotriton also has a sharp, forward-facing hook on each quadrate bone near the surface of skin bearing enlarged granular glands. Paramesotriton chinensis is unique among all salamanders in that it flips onto its back when bitten by shrews. This behavior displays the brightly patterned ventral surface. Paramesotriton caudopunctatus lacks the bright venter and does not flip onto its back when attacked. Pachytriton brevipes, an aquatic salamandrid, does not display any antipredator behavior other than escape, although it is distasteful to shrews. Mertensiella caucasica displays an active posture in which the body is coiled and the tail is elevated over the head and undulated or lashed toward a touch. This display is similar to those of many plethodontids and ambystomatids but is not found in any other salamandrid.

The potential for long-term sperm competition in a plethodontid salamander

Abstract: Fourteen Desmognathus ochrophaeus females each laid a complete clutch of fertilized eggs in the laboratory. The spermatheca of each female was examined histologically to determine whether stored sperm were retained after ovulation. All 14 females retained apparently viable sperm which were histologically indistinguishable from spermathecal sperm observed in pre-ovulatory females. Multiple mating and sperm storage are necessary criteria for sperm competition within a single oviposition period, but the storage of viable sperm even after oviposition creates the potential for long-term sperm competition from one oviposition period to the next.

A new species of Abronia (Sauria: Anguidae) with comments on the herpetogeography of the highlands of southern Mexico

Abstract: A new species of Abronia is described from the cloud forest of Cerro Bauil, Oaxaca, M6xico. The closest relative of this species appears to be A. reidi of the Sierra de los Tuxtlas in southern Veracruz. The discovery of this species provides additional evidence of past faunal inter- change of cloud forest species across the Isthmus of Tehuantepec. The lowlands of the Isthmus region have been considered to be one of the major barriers to the dispersal of highland faunas in Middle America. Nevertheless, examples of species or closely related species displaying a disjunct pattern of distribution on either side of the Isthmus are relatively numerous. The various regions that share portions of their herpetofaunas with the southeastern Oaxacan highlands appear to be in order of similarity, the highlands of northern Chiapas, the Pacific highlands of Nuclear Central America including the Sierra Madre de Chiapas and southern volcanic highlands of Guatemala, the Sierra de los Tuxtlas, and the northern Oaxacan highlands including the Sierra Juasrez and

Movements of juvenile American crocodiles in Gatun Lake, Panama

Abstract: The movement patterns of juvenile American crocodiles, Crocodylus acutus, were observed in Gatun Lake, Panama, by nighttime censusing and radiotelemetry in February and March 1981. Ten juveniles (nine 10 mo old, one 22 mo old) were radiotelemetered for an average of 233 fixes for each individual. The 10 mo old animals stayed within 300 m of the nest and had home ranges averaging 330 m of shoreline; 80% of movements occurred within core areas averaging less than 200 m. The 22 mo old animal dispersed about twice as far and included within its range at least twice as much shoreline as the younger animals. On the basis of sharp reductions in the strength of the radio signals when animals submerged, I inferred that 35-45% of the animals were in exposed locations on the surface during the day, and <65% at night. Movements between locations were rare from 0900-1700 h, increased mark- edly after dusk, peaked around 0300 h, and dropped to near zero 2 h after dawn. Nocturnal movements were significantly reduced during periods of bright moonlight, although the percentage of animals exposed at the surface did not noticeably change.

A population analysis of the ovoviviparous lizard Sceloporus jarrovi in the Pinaleno mountains of southeastern Arizona

Abstract: The life history and demography of a population of Yarrow's spiny lizard, Sceloporus jarrovi, was studied in the Pinalefio Mountains of southeastern Arizona from 1972-1974. Sizespecific clutch sizes and maximum female body size were smaller in the Pinalefio Mountains than in a population at similar elevation in the Chiricahua Mountains. A female of average snout-vent length (72 mm) in the population studied here had 5.6 ? 1.9 (SE) offspring. Males grew faster than females at all ages and were significantly larger. Survivorship of young and adults varied between years with average adult female survivorship being 36%. Winter (October-May) survivorship was higher than summer (June-October) survivorship. Adult population densities were highest in the spring and steadily declined through the summer. Sex ratios among yearlings, but not other age classes, differed significantly from an expected 1:1 ratio. Life tables based on average age-specific fecundity and mortality rates resulted in net replacement rates (RO) of about 1.0. The average generation time of the Pinalenio population was slightly longer than for a Chiricahua population. Possible differences in environments of the Pinalefio and Chiricahua mountains are discussed in relation to the observed differences.

A model for assessing mean age-specific fecundity in sea turtle populations

Abstract: A model is developed to estimate mean age-specific fecundity for sea turtle populations Information on the numbers of eggs laid by female turtles of known relative ages is used to estimate the mean number of eggs that will be laid by females that are reproducing at a given age Information on the frequencies of interseasonal nesting intervals is then used to adjust mean age-specific fecundities to reflect the substantial proportion of females in each age class that do not reproduce in a particular season (ie, at a particular age) The model is developed with data collected on adult female loggerhead turtles, Caretta caretta, nesting on Little Cumberland Island, Georgia, USA, from 1969 through 1981 The model is applicable to species of both marine and freshwater turtles in which individual females may not reproduce each year (ie, at each consecutive age)

Estimating prey size and number in crayfish-eating snakes, genus regina

Abstract: Snakes of the genus Regina feed almost exclusively on crayfish. The paired, sym- metrical gastroliths of crayfish are not digested and are detectable from x-rays of the snake. Gastrolith length is directly proportional to carapace length and can be obtained from x-rays. Carapace length can be converted to kcal of ingested energy. Using these relationships and repeated captures of radio-telemetered Regina, estimates of food consumption and energy intake by free- living snakes are feasible. New information on prey selectivity, feeding behavior, and predator- prey size relations in Regina grahami and R. septemvittata are presented and compared with similar data for other snakes.

Low clonal diversity in the parthenogenetic lizard cnemidophorus neomexicanus (sauria: teiidae)

Abstract: Electrophoretic analysis of proteins coded by 19 loci in the hybrid parthenogenetic lizard C. neomexicanus and its parental species, C. tigris marmoratus and C. inornatus, revealed two clones which differ in genotype at one enzyme locus, malate dehydrogenase-1. One clone occurred at six of seven localities and the other was present at only one locality. A comparison of C. neomexicanus with another parthenogenetic species, C. tesselatus, suggests that the extent of the geographic and ecological distributions of parthenogenetic species of Cnemidophorus is di- rectly related to the degree of clonal diversity.

Platemys macrocephala, a new species of chelid turtle from central bolivia and the pantanal region of brazil

Abstract: A new species of chelid turtle, Platemys macrocephala, is described from the upper Rio Mamor6 of central Bolivia and the Pantanal region of the upper Rio Paraguai of Brazil. It is most closely related to P. radiolata and differentiated mainly by its wider head, more robust skull, and larger body size.

Life history of the desert iguana, dipsosa ur us dorsalis

Abstract: A population study of marked Dipsosaurus dorsalis was conducted at Thousand Palms, California. Growth of hatchlings and some yearlings occurred at a mean rate of over 22 mm/yr in snout-vent length. Growth during high rainfall years was twice that during low rainfall years. Reproductive size was attained by 82% of the 1979 cohort at 31-33 mo of age. Recapture data showed that D. dorsalis remain close to their hatching sites, suggesting little or no emigration or immigration. Survivorship was high in all age classes. Average annual survivorship was 73% for hatchlings, 43% for yearlings, 46% for two year olds, and 60% for adults. There were no significant differences in annual survivorship of subadult and adult desert iguanas. Mean annual survivorship of adult males (57%) and females (66%) also was not significantly different. Two D. dorsalis in this study lived at least 7.5 yr. Spring density estimates (excluding hatchlings) were 332/ha and 425/ ha. Life history traits of this population of D. dorsalis appear to fit most closely those for organisms termed K-selected and constitute a reproductive strategy best characterized as late-maturing, single brooded.

Biennial reproduction in the lizard Eumeces okadae on Miyake-Jima, Japan

Abstract: The female reproductive cycle of the lizard Eumeces okadae on Miyake-jima, an island of Izu Archipelago, Japan, was studied by autopsy and mark-recapture methods. Mature females ranged from 72-94 mm in SVL and a clutch of eggs was laid from mid-June to early July. Clutch size varied from 4-12 with a mean of 7.6 eggs. Females brooded eggs for about 37 days until hatching. During brooding, females suspended foraging and food intake was reduced mark- edly. Fat body mass was maximal prior to yolk deposition and minimal just after brooding. Most mature females reproduced biennially, with 47-64% of mature females being reproductive in a given year.