Eleven fish species were identified from Homestead Cave, Utah. The remains, concentrated in the lowest stratum of the deposit, were accumulated by owls between approximately 11,200 and 10,100 ¹⁴C yr B.P. and likely represent fish associated with the final die-off of the Lake Bonneville fauna. Four of the species (Salvelinus confluentus, Prosopium abyssicola, Catostomus discobolus, Richardsonius balteatus) represent their first records for Lake Bonneville. The S. confluentus premaxilla is the first Quaternary specimen record for the genus in the Great Basin and suggests a southern range extension during the Pleistocene. The C. discobolus specimens represent the first fossil records for the subgenus Pantosteus in the Great Basin; their presence in Lake Bonneville documents a Pleistocene connection between two presently disjunct populations. The hyomandibulars of Prosopium gemmifer are different from Recent specimens in a pattern suggesting Holocene introgression with Prosopium spilonotus. The lack of Cottus echinatus and the presence of both Cottus bairdi and Cottus extensus may suggest the former species evolved in Utah Lake over the last approximately 10,000 yr B.P. The abundance of Catostomus ardens and the absence of Chasmistes liorus may reflect a restricted spatial distribution of the latter in Lake Bonneville.

Maximum parsimony analysis of 164 morphological characters supports the monophyly of crown-genus Crocodylus relative to other extant lineages. Crocodylus cataphractus is the basalmost living species, and monophyletic New World and Indopacific assemblages are supported. The Indian Mugger (Crocodylus palustris) is closely related to the Indopacific assemblage. Most fossils assigned to Crocodylus do not belong to the crown genus. Only one extinct fossil included in the analysis, Crocodylus palaeindicus (= C. sivalensis), falls within the crown-group Crocodylus and is of uncertain affinities within the group; Adams consensus trees draw C. palaeindicus toward the root of non–cataphractus Crocodylus, and the Nile crocodile (C. niloticus) is the sister taxon to the New World assemblage. The oldest fossil diagnostically belonging to the clade is from the Late Miocene, which is congruent with previous protein distance estimates of a Late Tertiary divergence among living species. Fossils and molecules never actually clashed regarding divergence timing, because very different meanings were applied to the name Crocodylus by paleontologists and neontologists.

When resources are economically defendable, interspecific aggression may occur when one species attempts to use the defended resources to the detriment of the defending species. In the Florida Keys, we investigated vigorous and frequently observed aggression between the Redband Parrotfish, Sparisoma aurofrenatum, and the Redtail Parrotfish, Sparisoma chrysopterum, along with microhabitat overlap and foraging overlap. Sparisoma chrysopterum home ranges extensively overlap S. aurofrenatum territories. Both parrotfishes are found over and feed upon Halimeda opuntia, a green calcareous alga, significantly more than all other microhabitats. Interspecific aggression by these parrotfishes is primarily directed toward confamilials. Extensive overlap in distributions combined with overlap in microhabitat and foraging behavior likely play a role in fostering the disproportionately high interspecific aggression observed between these two parrotfishes in the Florida Keys.

Sonoran Mud Turtles (Kinosternon sonoriense) are widely believed to be restricted to permanent bodies of water, yet some populations apparently thrive in canyons that dry completely. We investigated the possibility that these turtles could estivate by subjecting individuals collected in the Peloncillo Mountains of New Mexico to 11 weeks without food or water. Turtles apparently used water stored in the urinary bladder to osmoregulate early in the period of deprivation. However, by the end, several blood chemistry parameters (including plasma osmolality, sodium and potassium concentrations, and blood urea nitrogen) had increased anhomeostatically to very high levels; most variables returned to original levels on rehydration. Hematocrit and plasma protein levels were unaffected, suggesting preferential defense of plasma volume by dehydrating turtles. Individuals varied in their burial behavior, and individuals that were surface active became more dehydrated and accumulated more urea than those that remained buried. We were unable to demonstrate metabolic depression or a decrease in evaporative water loss (EWL) during the trial, but rates of resting metabolism and EWL in K. sonoriense were similar to those of Oklahoma-collected K. flavescens (a species well known to estivate) treated identically. Kinosternon flavescens produced less nitrogenous waste than did K. sonoriense and may have been more uricotelic but also incurred more severe hypernatremia. All but one K. sonoriense recovered upon return to water. We conclude that Sonoran mud turtles from this population are physiologically capable of surviving many weeks without food and water. The concept of estivation as a special physiological state (as opposed to a behavior) is critically discussed.

Investigations of phylogenetic relationships using comparative morphological characters have led to the hypothesis that Ammocrypta is the sister taxon of the Etheostoma subgenus Ioa. Subsequent molecular analyses have not recovered this proposed relationship. In this investigation, variation in complete cytochrome b sequences sampled from 27 percid species, representing all darter genera and all species of Ammocrypta, is examined in a phylogenetic context. Third codon purine transitions are saturated when all darter species examined are compared; however, saturation is not detected in any character class among species of Ammocrypta. Maximum-parsimony analysis, which excludes potentially homoplasious character classes, and maximum-likelihood analysis of cytochrome b sequences statistically reject the hypothesis that Ammocrypta is the sister taxon of the Etheostoma subgenus Ioa. Etheostoma is not recovered as monophyletic; however, the hypothesis of monophyly cannot be rejected using maximum-parsimony and maximum-likelihood methods. Morphological characters are combined with cytochrome b sequences in a total evidence analysis of relationships within Ammocrypta. A novel hypothesis of relationships is proposed, which includes a sister-taxon relationship between A. clara and A. pellucida. With regard to relationships among species of Ammocrypta, the morphological data do not significantly conflict with the cytochrome b data. Morphological characters provide additional synapomorphies supporting the hypothesis that A. beani and A. bifascia are sister taxa. The biogeographic implications of the total evidence analysis are discussed, and the continued taxonomic placement of Ammocrypta in Etheostoma is discouraged.

We studied the reproductive ecology of the teiid lizard Cnemidophorus lineatissimus during 1993 and 1994 near Chamela, Jalisco, México. We estimate that males reached sexual maturity at a snout–vent length (SVL) of 51 mm and an age of five months, and females reached sexual maturity at a SVL of 62 mm and an age of seven months. Testicular mass increased from April to July, reaching maximal size between August and December, and decreased in January of the next year. Gonads of females began to increase in mass during June when vitellogenesis occurred. They reached maximum mass from July to November when most egg production occurred. Some egg production occurred in January as well. The reproductive season for males and females is extended, similar to many other tropical lizards. Mean clutch size was 4.1 ± 0.2 eggs. Clutch size was correlated with female size, but egg size and relative clutch mass remained constant among females and between years. Mean clutch size and female body condition were lower in 1993 compared to 1994, presumably reflecting the effects of annual variation in resource availability on females. Proximal climatic factors influence the timing and intensity of reproduction in C. lineatissimus, but the historical effect of foraging mode on teiid lizard morphology constrains relative clutch mass. Sexual dimorphism is evident with males reaching larger size than females, and seasonal variation in mean SVL in both sexes suggests that much of the population is replaced annually.

Estudiamos la ecología reproductiva de la lagartija teíida, Cnemidophorus lineatissimus, durante 1993 y 1994 cerca de Chamela, Jalisco, México. Estimamos que los machos alcanzaron la madurez sexual a la longitud hocico-cloaca (LHC) de 51 mm y a una edad de 5 meses, y las hembras alcanzaron la madurez sexual a una LHC de 62 mm y a una edad de 7 meses. La masa testicular aumentó de abril a julio, llegando a su tamaño máximo entre agosto y diciembre, y disminuyó en enero del año siguiente. Las gónadas de las hembras empezaron a aumentar en masa durante junio cuando la vitelogénesis sucedió. Alcanzararon su masa máxima de julio a noviembre cuando ocurrio la mayo producción de los huevos. Una parte de la producción de los huevos también ocurrió en enero. La época reproductiva para los machos y las hembras es prolongada, parecida a muchas otras lagartijas tropicales. El promedio de la puesta fue de 4.1 ± 0.2 huevos. El tamaño de la puesta estuvo correlacionado con el tamaño de la hembra, pero el tamaño del huevo y la masa relativa de la puesta se mantuvieron constantes entre hembras y entre años. El promedio de la puesta y la condición corporal de las hembras fueron más bajos en 1993 que en 1994, presumiblemente reflejando los efectos de la variación de la disponibilidad anual de recursos para las hembras. Factores climáticos inmediatos influyen el patrón temporal y la intensidad de reproducción en C. lineatissimus, pero en el efecto histórico del modo de alimentar en la morfología de las lagartijas teíidas restringe la masa relativa de la puesta. Se nota el dimorfismo sexual, en que los machos alcanzan un tamaño mayor que las hembras, y la variación estacional en el promedio LHC de ambos sexos sugiere que mucho de la población cambia anualmente.

The current distribution of the River Blenny Salaria (= Blennius) fluviatilis, one of the two freshwater representatives of a large, cosmopolitan marine fish family, poses an interesting biogeographical problem because this species inhabits widely separate circum-Mediterranean watersheds. Potential scenarios of its dispersal were examined using allozyme analysis of several populations from the Iberian and Greek peninsulas. Based on Nei genetic distances, the most divergent populations were the populations inhabiting lakes, Lake Trichonis in Greece, and Ruidera Lakes in Spain. Their high divergence suggests their early isolation from the main ingroup populations. In contrast, low genetic distances were found among river populations regardless of geographic location. There was a correlation between genetic distance and geographic distance among Iberian river populations, suggesting that dispersal following the colonization of fresh water occurred via the sea to nearby, unconnected river basins. The ancestor of S. fluviatilis may have been a euryhaline species, allowing incursions into fresh water and subsequent dispersal via the sea. This dispersal scenario could theoretically be combined with multiple colonization episodes. The two old lake populations shared a unique allele at the Pgdh-A locus in high frequency with its closest relative S. pavo, which was absent from other populations. This may indicate two initial incursions into fresh water by a wide-ranging marine ancestor that possessed this allele. Differential selection on this allele in lake habitats or convergence are less likely possibilities. Thus, the present distribution of S. fluviatilis appears to stem from a combination of “raceme” origins (i.e., more than one colonization episode) and subsequent dispersal and divergence in new watersheds.

La distribución actual del blenio de río, Salaria (= Blennius) fluviatilis, uno de los dos representantes de agua dulce de una gran familia cosmopolita de peces marinos, plantea un interesante problema biogeográfico ya que esta especie vive en aguas circummediterráneas ampliamente separadas. Mediante el estudio de aloenzimas de varias poblaciones de la península Ibérica y Grecia se han analizado los escenarios potenciales para su dispersión. Las poblaciones más divergentes, basándonos en las distancias genéticas de Nei, fueron las pertenecientes a lagos, Lago Trichonis en Grecia y las Lagunas de Ruidera en España. Su gran divergencia sugiere su aislamiento temprano del resto de las poblaciones. Contrariamente, las poblaciones de los ríos mostraron distancias genéticas bajas independientemente de su localización geográfica. En las poblaciones ibéricas se encontró correlación entre las distancias genéticas y geográficas sugiriendo que la dispersión posterior a la colonización del agua dulce entre cuencas independientes se produjo a través del mar. El ancestro de S. fluviatilis podría haber sido una especie eurihalina, lo que le permitiría incursiones en el agua dulce y una posterior dispersión a través del mar. Este escenario podría teóricamente combinarse con múltiples episodios de colonización. Las dos poblaciones antiguas de los lagos comparten con su especie más cercana, Salaria pavo, un alelo único en el locus Pgdh-A en alta frecuencia, no presente en el resto de las poblaciones. Esto podría indicar dos incursiones iniciales en el agua dulce de un ancestro marino ampliamente distribuido que poseyera este alelo. La selección diferencial en hábitats lacustres o la convergencia de este alelo son hipótesis menos probables. Así pues, la distribución actual de Salaria fluviatilis parece ser una combinación de un origen en “racimo” (i.e., más de un episodio de colonización), y una posterior dispersión y divergencia en nuevas masas de agua.

We present evidence of an opportunity to measure the strength of natural selection on body size through size-specific winter mortality of freshwater turtles. Data were collected from three overwintering sites along the Missouri River floodplain in central Missouri. Carcasses and live captures of four species indicated that mortality was nonrandomly distributed among species and may be explained by differences in overwintering behaviors. Analyses of mean body size within age classes for two species demonstrated standardized selection differentials ranging from 0.23–0.98 (standard deviation units) against small-sized (juvenile) individuals. Our study provides evidence of winterkill as a selective force on body size and of a possible adaptive mechanism for Bergmann's Rule.

Parental investment as manifested through extended parental care of young presumably enhances the reproductive success of the custodial parent. In the Tessellated Darter (Etheostoma olmstedi), the primary caregivers are breeding males on the nest. However, prior field observations on nesting darters seem suggestive of behaviors that are more difficult to interpret evolutionarily. These include tending clutches that may have been fertilized by other males and appropriating nests from smaller courting males. To address such possibilities genetically, we assayed six microsatellite loci in 16 nest-tending males and the embryos from their associated clutches. In most cases, a guardian male had sired nearly all of the embryos in his nest. However, in one nest, a guardian male had been cuckolded, and in two other nests, an attendant male guarded embryos that were not his own presumably resulting from nest takeovers. From direct genotypic counts, a mean of at least 3.2 mothers contributed to the progeny in a nest, and computer simulations suggest that the true maternal number may be substantially higher.

We report reproductive characteristics (timing of sexual maturity, clutch frequency, clutch size, egg and hatchling sizes) of the Island Lizard Podarcis atrata. Reproductive performance was related to female size. The larger females initiate reproductive activities early in the season and produce two to four clutches annually, whereas the smaller individuals postpone reproduction until the season is well advanced and lay only a single clutch. Clutch size increased with female length and was slightly lower for clutches laid during June–July than for those produced during May. Among-clutch differences in egg mass were negatively correlated with clutch size, and this relationship is independent of female size. Larger clutches are also composed of less elongated (i.e., rounder) eggs than are smaller clutches, suggesting that the phenotypic trade-off between egg size and numbers is induced by limitations posed by the females' body volume, rather than by restrictions of energy availability. Comparison of reproductive traits of P. atrata to those of the closely related P. hispanica and P. bocagei indicates that the increase in body length during the evolutionary divergence of P. atrata was not associated with an increase in clutch size. This provides a clear exception to the general pattern found in lacertid lizards.

En este estudio proporcionamos información sobre las características reproductoras (alcance de la madurez sexual, frecuencia de puesta, tamaño de los huevos y de los jóvenes) de la lagartija insular Podarcis atrata, en relación con el tamaño de la hembra. Las hembras de mayor tamaño iniciaron su actividad reproductora al comienzo de la temporada, y produjeron entre dos y cuatro puestas al año. Sin embargo, las hembras más pequeñas retrasaron el inicio de su actividad reproductora y sólo realizaron una puesta al año. El tamaño de puesta incrementó con la longitud corporal de la hembra, y fue ligeramente inferior en las puestas realizadas en junio y julio que en las puestas producidas en mayo. Las diferencias entre puestas en el peso del huevo estuvieron negativamente correlacionadas con el tamaño de puesta, independientemente del tamaño de la hembra. Además, en las puestas más grandes, los huevos tenían una forma menos elongada (i.e., redondeados) que en las puestas más pequeñas. Los resultados anteriores sugieren que el “trade-off” entre el tamaño del huevo y de la puesta debe estar inducido por las limitaciones impuestas por el volumen de la hembra, más que por restricciones de disponibilidad de energía. La comparación de las características reproductoras de P. atrata con las de otras especies relacionadas, P. hispanica y P. bocagei, ha indicado que el incremento en la longitud corporal durante la divergencia evolutiva de P. atrata no ha estado acompañado de un incremento en el tamaño de puesta. Esto constituye una clara excepción del patrón encontrado en lacértidos.

Life-history aspects of Noturus phaeus, the Brown Madtom, were studied from August 1993 to July 1994 using samples collected from Bay Springs Branch (Little Tallahatchie River drainage), Mississippi. Noturus phaeus exhibited nocturnal feeding with a diet composed primarily of dipteran larvae, trichopteran larvae, and decapods (crayfish). Annuli from otoliths were successfully used to assist in age-class identification. It was common for individuals of both sexes to reach age-3, whereas some males were age-4 or older. Brown madtoms used woody debris and undercut banks as their primary daytime microhabitat, and stream flow (complex, run, pool) was the best predictor of the presence/absence of madtoms, being most often found in areas of complex (varying) flow. Abundance (density) was similar to those of other species, and N. phaeus was not collected in areas without either debris, aquatic vegetation, or undercut banks.

Andohahela Réserve Naturelle Intégrale is located in southeastern Madagascar. It consists of three parcels, the largest of which (Parcel 1, 63,100 ha), lying on the eastern flank of the Anosyenne Mountains between 90 and 1972 m elevation, is dominated by rain forest. We surveyed the herpetofauna of Parcel 1 at the beginning of the warm, rainy season between 20 October and 5 December 1995. We recorded 45 amphibian and 32 reptile species in Parcel 1, including a new species of Phelsuma, which we describe in this paper. This new species, Phelsuma malamakibo, is a medium-sized, rock-dwelling species which occurs in primary rain forest at elevations between 810 m and 1940 m. It is identified by the presence of a distinct dark lateral stripe on the neck and body with a white lateral stripe beneath it and a second, thin dark lateral stripe below the white stripe; greenish dorsal ground color with reddish brown spots arranged into three longitudinal rows or lines on the neck and back; no sexual dichromatism; a median cleft dorsally on the rostral scale; nostrils centered above the first supralabial scale; subequal subcaudal scales; keeled gular and anterior chest scales; and smooth (unkeeled) scales on the ventral surfaces of the body and tail. In most respects, this new species is similar to Phelsuma lineata, P. pusilla, and P. quadriocellata; however, these species have keeled ventral scales. Phelsuma malamakibo is similar to P. modesta in having smooth ventral scales, but the latter species is sexually dichromatic and differs from P. malamakibo in details of coloration and nostril position, as well as habitat. Phelsuma modesta is largely arboricolous in variable, usually drier habitats, whereas P. malamakibo is saxicolous in rain forest.

Tomiyamichthys alleni is described from eight specimens from Japan and Indonesia. The species is distinguishable from the only congener T. oni and closely related genus Flabelligobius in having the following combination of characters: occipital region narrow, equal to interorbital width, separated from upper margin of cheek by an irregularly curved groove; anterior oculoscapular canal with pores B′, C(S), D(S), F, and G′ (F located in groove between occipital region and cheek); first dorsal fin triangular, first and second spines elongated and filamentous; second dorsal and anal fin soft rays 10. The species occurs between 15 m and 40 m on fine sandy bottoms and is associated with the shrimp Alpheus randalli.

A new species of the leptodactylid frog genus Eleutherodactylus is described from Guaraqueçaba, State of Paraná, southern Brazil. The new species is characterized by its large size, slightly rugose to rugose dorsal skin texture, robust body, and low number of pulses per call. Descriptions of the advertisement calls of the new species and of E. manezinho, a close related species, are provided, as well as information on natural history.

Uma nova espécie de anuro do gênero Eleutherodactylus é descrita de Guaraqueçaba, Estado do Paraná, sudeste do Brasil. A nova espécie é caracterizada pelo grande porte, textura da pele dorsal levemente rugosa a rugosa, corpo robusto e pequeno número de pulsos por canto. São descritas as vocalização de anúncio da nova espécie e de E. manezinho, uma espécie próxima, bem como informações sobre história natural.

Egg mimics in Etheostoma (Catonotus) oophylax appear before the beginning of the breeding season and reach maximum size in the middle of the season when most spawning activity is expected. Mimic length, but not width, increases with male body size. Males of this species display laterally to females, and, as expected if the trait is subjected to female choice, the lateral dimension of the mimic is the largest. Egg mimics varied from 0.5 to 1.8 mm in length, potentially providing a wide choice for females. Eggs of E. oophylax average 2.2 mm in diameter, which is 22% larger than the largest mimics. If female choice of males or nest sites is determined by how effectively males mimic eggs, or how conspicuous mimics are, large males and males holding territories in the middle of the breeding season when mimics are largest have the advantage. If mimic size is important, choice of resources, that is, presence or absence of eggs in the nest site, may be more important to females than choice of male.

We estimated effective population size (N_e) in Collared Lizards (Crotaphytus collaris) via ecological and genetic methods. The ecological method employed life-history data from three years of mark-recapture studies and yielded an N_e estimate of 46. The genetic method used allele frequency changes over one generation and yielded an N_e estimate of 33 (95% CI; 10, 76). Dispersal, measured as displacement of territories or home ranges in one season, was low (average = 30.5 m) and did not differ among life-history stages or between sexes. Gene flow among habitat patches at our study site appeared sufficient to prevent genetic divergence or subdivision within the population. The observed small effective population size supports models of evolution in C. collaris, wherein stochastic processes could influence strongly the evolution of this species. Similarities in estimates of N_e suggest that the effective population size of this population does not differ from the size of a recent founder population and, moreover, that genetic and ecological methods yield compatible results when assumptions of the two methods are satisfied by the study design.

We describe the life-history pattern of Phalloceros caudiomaculatus on the basis of wild-caught and preserved fish from four different South American locations and laboratory data on livestock from a fifth location. This species is matrotrophic; the estimated dry weight of the young at birth is up to five times the weight of eggs at fertilization. In addition, these fish lack superfetation, meaning that there is only one brood of developing young at a time. This observation suggests that matrotrophy and superfetation can evolve independently of one another. The size distribution of mature males was bimodal in two of three samples and significantly skewed in the third. Such size distributions have indicated the presence of a genetic polymorphism for age and size at maturity in other species of Poeciliidae.

The relationship between local and regional diversity in viperid snake assemblages from South America was estimated. However, viperid species richness was spatially patterned across the continent, and this result can bias significance levels of regression analyses. To overcome this problem, we determined the minimum distance between localities that ensures stochastic independence of diversity estimates across space, using geostatistical analyses. We analyzed the relationship between local and regional diversity at three different spatial scales, by increasing region size. For the three scales, there was a significant linear relationship between local and regional diversity, indicating that local viperid assemblages are unsaturated and that their local diversity is constrained by species richness of the regional pool. Overall, this result indicates the importance of regional and historical processes on the determination of viperid species richness at local scales.

Neste trabalho, a relação entre diversidade local e regional foi estimada para comunidades de serpentes viperídeas da América do Sul. Entretanto, como a diversidade local está padronizada espacialmente em escala continental, há um viés nas análises de regressão relacionando esses componentes. Para corrigir esse problema, procedimentos de análise geoestatística foram utilizados a fim de determinar a menor distância geográfica entre localidades que garante independência estocástica entre as estimativas da diversidade local. A relação entre diversidade local e regional foi analisada em três escalas espaciais, ampliando sucessivamente a área da região. Em todas essas escalas, uma relação significativa entre as estimativas foi encontrada, indicando que as comunidades locais não estão saturadas e que sua diversidade é restrita pelo conjunto de espécies na região. De um modo geral, esse resultado mostra a importância de processos regionais e históricos, em grandes escalas de tempo e espaço, determinando a diversidade das serpentes viperídeas em escala local.

Two Hydrolagus affinis caught off Azores (Lucky Strike vent field) were identified as consumers of the hydrothermal vent mussel Bathymodiolus sp. It is the first notice of a vertebrate feeding on this endemic mytilid species.

We measured the standard metabolic rate of paedomorphic Mole Salamanders (Ambystoma talpoideum) from South Carolina. Despite an absence of body size differences between females and males, analysis of covariance demonstrated metabolic rates (mL O₂/h) were significantly influenced by an interaction between sex and body size. The interaction appeared as a result of changes in the size-metabolism relationship in males (a steeper slope in the size-metabolism regression in small males as compared to large males), whereas the relationship remained constant in females, regardless of size. We hypothesize that the observed differences are attributable to differences in reproductive physiology between the sexes. The results of this study underscore the need to evaluate the potential interactions among relevant variables in studies of metabolism, which heretofore have been disregarded in studies of salamander physiology.

The cause of size differences among developing fish is often not clear. We examined variability in egg size and in incubation time to determine whether either influenced hatching size or initial rates of growth in Japanese Medaka (Oryzias latipes). We also tested the prediction that larger females should produce heavier and/or more eggs. Our results indicated that larger females produce more, but not larger, eggs. Both egg volume and incubation time were positively, although weakly, correlated with the size of fry at hatching. Within-female variation accounted for substantially more variation in both egg size (69.9%) and hatching lengths of fry (79.3%) than did variation among females. Variation in egg volume, hatching size, and size at three-days posthatching (in the absence of feeding) decreased, as indicated by coefficients of variation for each (11.6, 4.8, 4.4). It is unknown whether slight differences in hatching size may contribute to subsequent variation in size when fry must compete for access to food.

Adults of Bocage's Wall Lizard (Podarcis bocagei), a lacertid endemic to the northwestern Iberian Peninsula, generally show marked sexual dichromatism with males having green dorsal coloration and females brown dorsal coloration. In some populations, however, some adult females show dorsal coloration similar to that of males. I used mark-recapture methods to study a population of this type on a coastal promontory in A Coruña. A proportion of adult females showed green dorsal coloration during the reproductive period (April–July), but not during the rest of the year. Green dorsal coloration was most frequent among females with oviductal eggs, whereas preovulatory females with vitellogenic follicles in all cases showed brown dorsal coloration. These findings suggest that the green dorsal coloration observed in some females may be related to stage in the reproductive cycle, with green coloration developing during the gravid phase (i.e., with fertilized eggs). The findings also raise the possibility that the function of this coloration may be to avoid harassment and copulation attempts by males following fertilization. According to this hypothesis, females show brown dorsal coloration during the receptivity period (and during the nonreproductive period). Following fertilization, and possibly as a result of the hormonal changes that accompany ovulation and fertilization, they develop green dorsal coloration. This suggests that coloration, in these lacertids as in other reptiles, plays an important role in social communication.

La lagartija de Bocage (Podarcis bocagei) es un lacértido endémico del noroeste de la Península Ibérica que presenta generalmente un marcado dicromatismo sexual, teniendo los machos adultos una coloración dorsal verde y las hembras parda. Sin embargo, en determinadas poblaciones, algunas hembras adultas muestran una coloración dorsal verde, similar a la de los machos. Se han utilizado métodos de marcaje/recaptura para estudiar una población de este tipo en una localidad costera de A Coruña. Un porcentaje de hembras adultas de esta población mostró coloraciones dorsales verdes durante el período reproductor (abril-julio), pero no durante el resto del año. La coloración dorsal verde fue más frecuente en las hembras que tenían huevos oviductales, mientras que las hembras aún no ovuladas, con folículos en vitelogénesis, presentaron en todos los casos coloraciones dorsales pardas. Estos cambios sugieren que la coloración dorsal verde observada en algunas hembras puede estar relacionada con un período determinado del ciclo reproductor, desarrollándose durante la fase de gravidez (con huevos fertilizados en su interior). Estas observaciones también permiten plantear la hipótesis de que este cambio de coloración en las hembras puede tener la función de evitar las persecuciones y los intentos de cópula por parte de los machos una vez que ya han sido fertilizadas. De acuerdo con esta hipótesis, las hembras muestran una coloración dorsal parda durante el período de receptividad (así como durante el período no reproductor), mientras que después de la fertilización, y posiblemente como consecuencia de los cambios hormonales que siguen a la ovulación y fertilización, desarrollan una coloración dorsal verde. Esto sugiere que la coloración juega un importante papel en el reconocimiento sexual en estos lacértidos, al igual que sucede en muchos otros reptiles.

Aspects of the reproductive biology of the Southern Stingray, Dasyatis americana, were determined from five captive adult females and their offspring. Mean size and weight of the neonates were 238.0 ± 1.6 mm disc width and 505.9 ± 10.7 g, respectively. Litter size (n = 47), which ranged from two to 10, averaged 4.2 ± 0.3 and varied directly with maternal size and indirectly with size and weight of neonates. Gestation (n = 47) ranged from 135 days to 226 days with a mean of 175.4 ± 4.1 days.

The digestive efficiencies of seven taxa of Australian pythons were examined with respect to body temperature, meal size, and passage time. The hair of rodents was not digested by the snakes. Digestive efficiencies were not influenced by body temperature, and the values ranged from 89% to 98% if hair was included and from 99.3% to 99.8% if hair was excluded from the analyses. The digestive efficiency of different food types can be made more comparable by taking into account the known indigestible components. Passage time was significantly longer at 24 C than at 30 or 33 C. Passage time was not related to relative meal size.

The taxonomy of the Asian gobiid genus Chaenogobius Gill, 1859, has been unclear for over a century because of the apparent absence of a type specimen for its type species, Chaenogobius annularis Gill, 1859. A specimen discovered in the USNM collection (USNM 6336) matches Gill's original description in virtually every particular and is herein recognized as Gill's holotype. Detailed examination of the holotype indicates that C. annularis is a senior synonym of Chasmichthys dolichognathus (Hilgendorf, 1879) and refutes the suggestion that C. annularis is a synonym of Chaenogobius urotaenia (Hilgendorf, 1879). These conclusions force significant changes in the taxonomy of this group and suggest that complete revisions of both genera are necessary.

We investigated whether the thermal history of Black Rat Snakes (Elaphe obsoleta) and Northern Water Snakes (Nerodia sipedon) during development affected their preferred body temperatures (PBT) after hatching or birth. Eggs of black rat snakes were incubated at high or low temperatures. Gravid female water snakes were maintained in rooms under low, medium, or high ambient temperatures. PBT of neonates were measured in a controlled thermal gradient. We only found plasticity in PBT with developmental temperature for northern water snakes, where offspring that developed under warmer temperatures demonstrated a significant preference for warmer temperatures. Our results suggest that PBT are plastic in only some species of snakes and may explain some of the individual variation in PBT observed in adult snakes.

The status of the eelpout Lycodes terraenovae Collett, 1896, has long been uncertain, because the syntypes were thought to have been lost. The types were located and examined in Monaco, and it is now clear that L. terraenovae is a valid species. It differs from the sympatric species (Lycodes esmarkii and Lycodes vahlii) by its uniform coloration, lack of predorsal lateral line, smaller and fewer palatine teeth, and position of last precaudal vertebrae in relation to dorsal fin.

We measured the increase in metabolic rate following feeding, or the specific dynamic action (SDA) of feeding, in the lizard Eulamprus tympanum that feeds opportunistically and frequently. The SDA of most reptiles studied to date is pronounced in relation to other vertebrates, but most species for which data are available consume large meals infrequently. We chose to measure SDA in E. tympanum because it is typical of most lizards in that it feeds frequently. The SDA pattern of E. tympanum is typical of other animals, where metabolic rate increases to a peak following feeding then gradually decreases to prefeeding values. Metabolic rate in E. tympanum increases by up to 2.4 times the prefeeding values and remains elevated for up to 48 h. The SDA effect is much less in a lizard that feeds opportunistically and frequently than in sit-and-wait foraging reptiles. The duration of the SDA is greater in E. tympanum than in many other vertebrates and may be related to an ectothermic lifestyle, meal size, or diet composition. On the basis of diet and feeding strategy, E. tympanum is probably typical of lizards that feed frequently, but there are too few data to make detailed comparisons.

Ambystomatid salamanders have been shown to have toxic and adhesive secretions which serve as important antipredator mechanisms. Here we show that at least one component in Ambystoma tigrinum secretion inhibits neurotransmission in slices of rat hippocampus. Further, we show that disulfide linkages in proteins are necessary for the adhesive properties of the secretion.

The identification of the cryptic diploid-tetraploid Gray Treefrogs, Hyla chrysoscelis and H. versicolor, from preserved specimens is problematic using conventional methods, such as karyotyping. Nucleolar number has been used as an index of ploidy for this purpose, based on the assumption of a single nucleolus per chromosome set. However, cytogenetic studies of nucleolar organizer regions (NORs) have shown that putative secondary NORs occur in some populations of the diploid, H. chrysoscelis. This study demonstrates that secondary NORs in the diploid genome are associated with additional nucleoli in interphase cell nuclei. The number of nucleoli is proportional to the total number of primary and secondary NORs, not ploidy level, and, therefore, is not a valid character for identification of specimens from populations having secondary NORs. Because little is known about the frequency of secondary NORs in most H. chrysoscelis populations, nucleolar number should be avoided as a primary means of species identification.

Freeze tolerance and cryoprotectant synthesis was examined in Hyla regilla, collected from Northern California in the spring and fall. Specimens frozen at 2 C for six and 12 hours had a survival rate of 10% and 80%, respectively, in both seasons. This is the first report of freeze tolerance for H. regilla. Freezing caused a fivefold increase in plasma glucose levels in the spring and a 14-fold increase in the fall. Ice formation induced a rise in liver glucose and glycerol production in both seasons with concentrations of liver glucose being greater in the fall than in the spring. The increase in glucose was accompanied by a significant decline in liver glycogen. Seasonal differences in muscle glycogen levels in response to freezing were not shown, suggesting that the liver is the organ responsible for cryoprotectant synthesis. The rise in plasma glucose, along with increased levels of liver glucose and glycerol in response to freezing, suggests that these compounds are being used as cryoprotectants, with glucose being the primary component.

We conducted a study of American Crocodile nesting ecology in coastal Belize from June 1996 to July 1997. Most nesting areas were found on elevated beach ridges composed of coarse sand. Shallow, brackish lagoons adjacent to nesting areas provide critical nursery habitat for hatchlings. The most significant nesting areas were found in the Turneffe Atoll. American crocodiles construct both hole and mound nests in Belize. Clutches are deposited during the last half of the dry season, from late March to early May. Mean clutch size is 22.3 ± 6.0 eggs. Hatching occurred from late June to mid-July, a period coinciding with the beginning of the wet season. Nesting success was high, and losses to predation and flooding were negligible. Females may defend nests from predators and excavate neonates at hatching, but otherwise parental care appears minimal. The protection of suitable nesting and nursery habitat is essential for the continued survival of the American crocodile in Belize.

In newts of the genus Triturus, there is behavioral and anatomical evidence for the existence of chemical communication. A laboratory study tested whether male Bosca's newts (Triturus boscai) preferred water in which they had been held over clean water or water in which other males or females had been held. Males preferred water that presumably contained chemical cues from themselves or other conspecifics, and males already paired with a female spent significantly more time in their home water than did single males. These observations suggest that male T. boscai were able to identify chemical cues from conspecifics and discriminate cues from females.

Los tritones pertenecientes al género Triturus presentan evidencias tanto anatómicas como comportamentales de la existencia de comunicación química. Se realizó un estudio de laboratorio para verificar si los machos de tritón ibérico (Triturus boscai) prefieren un estanque que contiene agua con su propio estímulo químico frente a un estanque con el estímulo químico de otros machos o hembras, o si prefieren agua que no contiene estímulos químicos de conespecíficos. Los resultados muestran que los machos prefirieron el agua que presumiblemente contenía sus propias señales químicas o las de otros conespecíficos, y que los machos que fueron emparejados con hembras pasaron significativamente más tiempo en su propio estanque que los machos no emparejados. Estos resultados sugieren que los machos de T. boscai son capaces de identificar en el agua señales químicas procedentes de conespecíficos y discriminar las señales químicas procedentes de las hembras.

Freeze-tolerant frogs experience marked changes in their cellular chemistry as a result of internal freezing, forcing them to incur metabolic costs that are likely remedied upon thawing. This study measured levels of O₂ consumption in Rana sylvatica after freezing for one and seven days at −1.5 C and thawing at 5 C. Oxygen consumption was measured 4, 8, and 28 h after the onset of thawing. Following a one-day freeze, frogs had a 30% lower O₂ consumption value after 4 h into the recovery than their prefreeze rate. After the seven-day freeze, the O₂ consumption of frogs was nearly as low (−25%) at 4 h, but the reading at 8 h was more than 40% above the control level. Frogs had O₂ consumptions equivalent to the control at 28 h following both treatments. Low rates of O₂ consumption early in postfreeze recovery corresponds to depressed systemic functions in frogs, and the level of O₂ consumption at 8 h following the seven-day freeze was possibly linked to disturbance of the cellular environment.

Oviposition behavior of Physalaemus pustulosus was studied using paired choice tests in small terraria. Given two possible nest construction sites (a dish with a conspecific nest in water and a dish with just water), pairs preferred to build nests in dishes that held only water. Avoidance of conspecific nests during oviposition may increase fitness by limiting potential intraspecific resource competition and by preventing tadpole growth inhibition.

Se estudió el comportamiento reproductivo de Physalaemus pustulosus empleando pruebas de selección de doble opción en pequeños terrarios. Dados dos sitios posibles de construcción de nidos (un recipiente con un nido coespecífico en agua y otro solo con agua) las parejas prefirieron oviponer en aquellos que contenían solo agua. Evitar los nidos coespecíficos durante la oviposición aumentaría la supervivencia, limitando la competencia intraespecífica potencial por los recursos e impediendo la inhibición del crecimiento de los renacuajos.

The importance of prey movement for stimulating feeding behavior of Brown Treesnakes was tested by using a mechanical mouse model in combination with and without prey odor. Prey movement was found to be important in stimulating brown treesnake feeding behavior. Prey movement combined with prey odor was not significantly different than prey movement alone. In the development of simple artificial lures based on the stimulus of live mice, visual lures lacking movement are likely to be ineffective. Lures that combine a visual moving stimulus with prey odor are likely to be the most effective artificial lure for trapping brown treesnakes.

The southwestern Atlantic Stingray Dasyatis macrophthalma Gomes, Rosa, and Gadig was described under two different names which appeared in the original publication by mistake. By using the First Reviser principle, according to the provisions of the International Code of Zoological Nomenclature, we select Dasyatis marianae as the valid name for the species. The name D. macrophthalma previously had been published by other authors in its homonym form D. macrophtalma, without reference to a formal description (a nomen nudum). It is herein treated as the junior objective synonym of D. macrophthalma. To avoid the repetition of similar cases, we recommend the authors preparing descriptions of new taxa refrain from publicizing manuscript names in the Web, scientific meetings, news media, or museum labels.