Showing papers in "Copeia in 1998"

The Biology of Sea Turtles

Abstract: Physiology as Integrated Systems Amanda Southwood Williard Vision Kerstin A. Fritsches and Eric J. Warrant Natal Homing and Imprinting in Sea Turtles Kenneth J. Lohmann, Catherine M.F. Lohmann, J. Roger Brothers, and Nathan F. Putman The Skeleton: An In Vivo View of Structure Jeanette Wyneken Age and Age Estimation in Sea Turtles Larisa Avens and Melissa L. Snover Molecular Genetics of Sea Turtles Michael P. Jensen, Nancy N. FitzSimmons, and Peter H. Dutton Oceanic Habits and Habitats: Dermochelys coriacea Vincent S. Saba Oceanic Habits and Habitats: Caretta caretta Katherine L. Mansfield and Nathan F. Putman Feeding Biology: Advances from Field-Based Observations, Physiological Studies, and Molecular Techniques T. Todd Jones and Jeffrey A. Seminoff Predators, Prey, and the Ecological Roles of Sea Turtles Michael R. Heithaus Exposure to and Effects of Persistent Organic Pollutants Jennifer M. Keller Fisheries Bycatch of Marine Turtles: Lessons Learned from Decades of Research and Conservation Rebecca Lewison, Bryan Wallace, Joana Alfaro-Shigueto, Jeff Mangel, Sara Maxwell, and Elliott Hazen Climate Change and Marine Turtles Mark Hamann, Mariana M.P.B. Fuentes, Natalie C. Ban, and Veronique J.L. Mocellin Free-Ranging Sea Turtle Health Mark Flint Sea Turtle Epibiosis Michael G. Frick and Joseph B. Pfaller Parasites of Marine Turtles Ellis C. Greiner Index

Application of Life-History Theory and Population Model Analysis to Turtle Conservation

Abstract: As more reptiles find their way onto endangered species lists, it is increasingly important to identify management alternatives that can be applied across taxa. I have compared life tables from several turtle populations using elasticity analysis, a method that calculates the proportional contribution of each vital rate (age-specific survival and fecundity) to the annual population multiplication rate, k [In (X) = r, the intrinsic rate of increase]. Most freshwater turtles share similar elasticity patterns across age classes, in spite of large variations in mean annual fecundity, annual survival, and age at maturity. High adult survival elasticity and low fecundity elasticity in these species suggests that conservation efforts that reduce mortality of adults are likely to stabilize declining populations. Desert tortoises and sea turtles had different elasticity patterns, with relatively higher juvenile elasticities when summed across age classes. Three different life tables for painted turtles also showed variation in elasticity patterns. Approximate elasticities can be generated for age-based matrices without a complete life table for each species, requiring only age at maturity, adult female annual survival, and population multiplication rate. This approximation may help identify sensitive life stages for poorly known species, thereby guiding research and management efforts and furthering our understanding of lifehistory patterns.

Molecular systematics of fishes

Abstract: C. Stepien, R.H. Rosenblatt and T.D. Kocher, Overview of the Classification and Phylogeny of Fishes: Morphology Versus Molecules. T.D. Kocher and K.L. Carleton, Evolution of Molecules in Fishes: Characters and Clocks. I. Kornfield and A. Parker, Molecular Systematics of a Rapidly Evolving Species Flock: The Mbuna of Lake Malawi and the Search for Phylogenetic Signal. H. Sultmann and W.E. Mayer, Reconstruction of Cichlid Fish Phylogeny Using Nuclear Dna Markers. J.L. Nielsen, M.C. Fountain, And J.M. Wright, Biogeographic Analysis of Pacific Trout (Oncorhynchus Mykiss) in California and Mexico Based on Mtdna and Nuclear Microsatellites. E.O. Wiley and R.H. Hagen, Mitochondrial Dna Sequence Variation Among the Sand Darters (Percidae: Teleostei). C. Stumbauer, E. Verheyen, L. Ruber, And A. Meyer, Phylogeographic Patterns in Populations of Cichlid Fishes from Rocky Habitats in Lake Tanganyika. E. Bermingham, S.S. Mccafferty, And A.P. Martin, Fish Biogeography and Molecular Clocks: Perspectives from the Panamanian Isthmus. J.E. Faber and C.A. Stepien, The Utility of Mitochondrial Dna Control Region Sequences for Analyzing Phylogenetic Relationships Among Populations, Species, And Genera of the Percidae. R.B. Phillips and T.H. Oakley, Phylogenetic Relationships Among the Salmoninae Based on Nuclear and Mitochondrial Dna Sequences. A. Parker, Combining Molecular and Morphological Data in Fish Systematics: Examples from the Cyprindodontiformes. G. Bernardi, Molecular Phylogeny of the Fundilidae (Teleotei, Cyprinodontiformes) Based on the Cytochrome B Gene. G.J.P. Naylor, A.P. Martin, E. Matisson, And W.M. Brown, The Inter-Relationship of Lamniform Sharks: Testing Phylogenetic Hypotheses with Sequence Data. G. Orti, The Radiation of Characiform Fishes: Evidence from Mitochondrial and Nuclear Dna Sequences. C.A. Stepien, Relationships Among Families, Tribes, And Genera in the Suborder Blennioidei, Based on Mt 12s Rna Sequences. J. Klein, D. Klein, F. Figueroa, And C. O'huigin, Major Histocompatibility Complex Genes in the Study of Fish Phylogeny. C. Lydeard and K.J. Roe, The Phylogenetic Utility of the Mitochondrial Cytochome B Gene for Inferring Relationships Among Actinopterygian Fishes.

The Biology of Xenopus

Abstract: Introduction Xenopus species and ecology (5 chapters) Behaviour, sensory perception, and development (6 chapters) Infections and defence (4 chapters) Phylogeny and speciation (6 chapters) Index

Phylogenetic analysis of skates, a morphologically conservative clade of elasmobranchs (chondrichthyes : rajidae)

Abstract: Skates (Rajidae) are unique among chondrichthyans for their high species diversity and morphological conservatism. To elucidate phylogenetic interrelationships within this taxon, we surveyed a wide range of morphological character complexes under the premise that characters within different character complexes are constrained in different ways and would thus reveal a robust phylogeny. Maximumparsimony analysis employing 31 taxa, including three outgroups, and 55 characters produced 20 equally parsimonious trees of 160 steps (consistency index = 0.681, retention index = 0.850, homoplasy index = 0.462, and rescaled consistency index = 0.579). The strict consensus tree divided rajids into two major clades. The first, Rajinae, consisted of two partially resolved clades and one fully resolved clade and was defined by three ambiguous character states: (1) scapulocoracoids that lack an anterior bridge; (2) claspers that are distally expandible; and (3) claspers that possess the component rhipidion. The taxon comprises three tribes, 15 genera (seven elevated from subgenera of Raja and GurgesieUa), and 149 species. The second major clade, Arhynchobatinae, was nearly fully resolved and was defined by two unambiguous character states: (1) basihyal cartilages that possess lateral extensions; and (2) claspers that possess the component projection. The taxon comprises two tribes, 11 genera, two genera elevated from subgenera of Raja, and 79 species. The strict consensus tree revealed considerable parallelisms in morphological evolution within rajids. Some parallelisms, such as reduction of the rostral cartilage and concomitant forward extension of pectoral radials and muscles and enlarged nasal capsules, appear to be adaptations for deep-sea benthic habitats. The closest relatives of rajids, Rhinobatos, Zapteryx, and Trygonorrhina, are limited to shallow water. Thus, it is likely that ancestral rajids had a similar habitat and that subsequently rajids made multiple radiations into the deep sea and developed flexible snouts for grubbing in soft substrates and enlarged nasal rosettes for increased chemosensistivty in regions with little light.

Quantifying Developmental Progress for Comparative Studies of Larval Fishes

Abstract: Several convenient metrics for quantifying the ontogenetic state of fish larvae (based on age, size, and thermal history) were assessed in terms of intrinsic variability, the influence of temperature, and variability among species. Data for 12 ontogenetic events were collected from Atlantic menhaden (Clupeidae: Brevoortia tyrannus) and 15 events from red drum (Sciaenidae: Sciaenops ocellatus). Each species was reared at two constant temperatures 4-5 C apart. Precise timing of events and the variability in timing were calculated using a method analogous to a "dose-response" relationship. The logarithm of total length had the lowest intrinsic variability of all metrics examined; dry weight and age had the highest variability. Warmer temperatures accelerated ontogenetic events on all measurement scales, especially age-based metrics. Logarithmic transformations of day-degrees and effective day-degrees were insensitive to temperature, but these metrics require information that is often not available. An ontogenetic index, which compares species on the basis of their size or age at metamorphosis, performed best in interspecific comparisons.

Ancient marine reptiles

Abstract: M.A. Taylor, Foreword. Ichthyosauria: J.M. Callaway, Introduction. P.M. Sander, The paleobiogeography of Shastasaurus. J.M. Callaway, A New Look at Mixosaurus. C. McGowan, A Transitional Ichthyosaur Fauna. R. Motani, Temporal and Spatial Distribution of Tooth Implantation in Ichthyosaurs. Sauropterygia: O.C. Rieppel, Introduction. O.C. Rieppel and H. Hagdorn, Paleobiology of Middle Triassic Sauropterygia in Central and Western Europe. G.W. Storrs, Morphologic and Taxonomic Clarification of the Genus Plesiosaurus. K. Carpenter, Comparative Cranial Anatomy of Two North American Cretaceous Plesiosaurs. Testudines: E.L. Nicholls, Introduction. R. Hirayama, Distribution and Diversity of Cretaceous Chelonoids. D.K. Elliott, G.V. Irby, and J.H. Hutchison, Desmatochelys Iowa, a Marine Turtle from the Upper Cretaceous. R.T.J. Moody, The Paleogeography of Marine and Coastal Turtles of the North Atlantic and Trans-Saharan Regions. Mosasauridae: G.L. Bell, Jr., Introduction. G.L. Bell, Jr., Phylogenetic Revision of North American and Adriatic Mosasauridea. A. Sheldon, Ecological Implications of Mosasaur Bone Microstructure. Crocodylia: S. Hua and E. Buffetaut, Introduction. R.K. Denton, Jr., J.L. Dobie, and D.C. Parris, The Marine Crocodile, Hyposaurus, in North America. Faunas, Behavior, and Evolution: J.A. Massare, Introduction. S.G. Lucas, Marine Reptiles and Mesozoic Biochronology. Z. Gasparini and M. Fernandez, Tithonian Marine Reptiles of the Eastern Pacific. R. Collin and C.M. Janis, Morphological Constraints on Tetropod Feeding Mechanisms: Why Were There No Suspenion-Feeding Marine Reptiles? R.L. Carroll, Mesozoic Marine Reptiles as Models of Long Term, Large-Scale Evolutionary Phenomena. Subject Index.

Reproductive Strategies and Egg Types of Seven Rio Grande Basin Cyprinids

Abstract: Reproductive strategy and egg type of Hybognathus amarus, H. placitus, Macrhybopsis aestivalis, Notropis girardi, N. jemezanus, N. simus pecosensis, and N. stramineus were determined from laboratory experiments conducted between 1991 and 1995. The first six taxa were pelagic-broadcast spawners that produced nonadhesive, semibuoyant eggs, whereas N. stramineus was a broadcast spawner that laid demersaladhesive eggs. High-speed cinematography revealed that a spawning event consisted of a single male wrapping around the female's midsection and fertilizing the eggs upon expulsion. The perivitelline space of recently expelled nonadhesive eggs filled rapidly with water, thereby increasing both egg diameter and buoyancy. Semibuoyant eggs remained in suspension as long as water current was maintained. Discovery of the spawning behavior and egg types of these species allowed for the development of hypotheses to explain extirpations and extinctions of several endemic Rio Grande Basin fishes. We believe the synergistic effects of downstream transport of eggs and larval fishes and dam-related modifications of flow and habitat was probably responsible for the decline and demise of these taxa in the Rio Grande Basin.

Vertebral Column Morphology, C-Start Curvature, and the Evolution of Mechanical Defenses in Tetraodontiform Fishes

Abstract: Maximum body curvature during the initial phase of escape swimming (stage 1 of C-start) was measured in four species of tropical marine fishes. A linear correlation between maximum curvature and number of functional intervertebral joints was found (range for number of joints, 17-25). A biomechanical model of vertebral column bending predicts that, if intervertebral joint angles are held constant, increasing the number of joints should produce a linear decrease in the measured curvature coefficient (curvature coefficient is inversely related to curvature). The measured curvature coefficients fit this model closely, indicating that, within the range of 17-25 joints, vertebral number is an important determinant of vertebral column flexibility. The study species with the lowest vertebral number, a filefish, Monacanthus hispidus, is a member of the Tetraodontiformes, a group characterized by the lowest vertebral numbers found among fishes. Elaborate antipredator defenses, such as a carapace and the ability to inflate the body, have evolved six times within the Tetraodontiformes, and some form of mechanical defense is present in all families of this group. We propose an evolutionary scenario in which low vertebral number reduced the escape swimming performance of ancestral tetraodontiforms, thus increasing their vulnerability to predators and driving the repeated evolution of mechanical defenses in this group. Our finding that lower vertebral numbers are correlated with lower C-start curvature suggests that low vertebral number may impair escape performance; thus, one necessary condition for the proposed scenario is met.

Feeding Morphology, Diet, and Ecomorphological Relationships among Five Caribbean Labrids (Teleostei, Labridae)

Abstract: The ecomorphological relationship between oral and pharyngeal jaw morphology and diet was investigated for five labrids: Lachnolaimus maximus, Halichoeres garnoti, H. bivittatus, H. maculipinna, and Thalassoma bifasciatum. The goals were to examine the following: (1) the relationship between diet and oral and pharyngeal jaw morphology; and (2) the influence of feeding behavior on diet. Twelve morphological measurements reflecting aspects of feeding ability were made. Interspecific differences in dentition were described. Principal components analysis (PCA) explained 96% of the variance among morphological variables with the first two PCs. Principal component 1 accounted for 92.2% of the variance, separating species by body size, whereas PC2 (3.8% of variance) separated species by oral jaw shape and degree of protrusibility. Twenty-six prey categories were identified. Canonical correspondence analysis (CCA) revealed that only 4.7% of the variation in diet was attributable to morphological variables, indicating a low correlation between oral and pharyngeal jaw characters and diet. However, variables that measured some aspect of performance were good predictors of diet. The proportion of hard prey consumed was correlated to the estimates of biting force for each species. Species with stronger pharyngeal jaw musculature consumed larger amounts of hard prey than those with lesser force generating ability. Feeding behaviors, classified as suction feeding, winnowing, or biting, corresponded to oral jaw morphology. Species with less protrusible jaws were found to bite their prey, and species with more protrusible jaws

Habitat Use during Breeding and Emigration in Radio-Implanted Tiger Salamanders, Ambystoma tigrinum

Abstract: Twenty-seven adult radio-implanted Ambystoma tigrinum from four ponds in Long Island, New York, were tracked for up to a year to examine adaptive flexibility in aquatic and terrestrial habitat use. Adults in two exposed breeding ponds preferred deep, vegetated areas. In a heavily shaded pond, the males segregated from the females and preferred nonvegetated areas, and in a pond with bluegills, the adults preferred shallow zones. On land, most resident salamanders remained close to a breeding pond that was immediately surrounded by a steep bank and woods, whereas few stayed close to exposed ponds with little ground cover. Salamanders were facultative emigrators, making major emigratory movements during spring, fall, or both, or not migrating at all. Two displaced salamanders showed normal pond activity but atypical terrestrial movements. Frequent predation occurred in small-mammal runways, most likely by short-tailed shrews. Salamanders excavated tunnels for temporary refuge but used small-mammal runway systems for long-term refuge. These new observations for A. tigrinum show adaptability in movements and habitat use during breeding and emigration consistent with the species' wide distribution in eastern North America.

Oral Deformities in Tadpoles of the Bullfrog (Rana catesbeiana) Caused by Conditions in a Polluted Habitat

Abstract: In this experiment, we tested for a causative relationship between the site in which bullfrogs developed during the embryonic and early larval period and presence of oral deformities. We reciprocally transplanted fresh egg masses of bullfrogs collected from the coal ash-polluted site and an unpolluted reference pond to test the main and interactive effects of the site in which tadpoles developed and the site inhabited by the parents, on the frequency of oral deformities in tadpoles.

Sex Determination and Sex Ratios of Pacific Leatherback Turtles, Dermochelys coriacea

Abstract: temperatures above 30.0 C during the critical sex determining period. The sex of all hatchlings determined by gonad histology for 18 monitored nests (n = 10-20 per nest) were 100% female. Estimated sex ratio for the 1993-1994 season was 0% male:100% female, for the 1994-1995 nesting season was 6.5% male:93.5% female, and for the 1995-1996 season was 25.7% male:74.3% female. These ratios were more female biased than sex ratios reported for the past 25 years in Suriname on the Atlantic coast of South America. Gene flow between populations and the response of leatherback populations to thermally different nesting areas may be responsible for the lack of intraspecific variation in pivotal temperature.

Acquired Recognition of Chemical Stimuli from an Unfamiliar Predator: Associative Learning by Adult Newts, Notophthalmus viridescens

Abstract: Many vertebrates recognize potential predators using only chemical cues (Weldon, 1990). Chemical detection of predators is particularly important at night, in dark or murky habitats, in areas with dense vegetation, or with cryptic or ambush predators, all conditions that are common in aquatic environments (Dodson et al., 1994). Chemical recognition of some common predators may be innate (e.g., Elliot et al., 1993). Natural selection also may favor the ability to learn to associate unfamiliar predators with danger (e.g., Maloney and McLean, 1995; Chivers et al., 1996). Previous attempts to demonstrate associative learning by amphibians have been relatively unsuccessful (Suboski, 1992). Chemical alarm signals play an important role in the antipredator behavior of many aquatic vertebrates (e.g., Hews and Blaustein, 1985; Smith, 1992; Mathis and Smith, 1993a). For amphibians, response to chemical alarm signals has been documented for some anuran tad-

Modifications of the Digestive Tract for Holding Air in Loricariid and Scoloplacid Catfishes

Abstract: Loricariid catfishes have evolved several modifications of the digestive tract that appear to function as accessory respiratory organs or hydrostatic organs. Adaptations include an enlarged stomach in Pterygoplichthys, Liposarcus, Glyptoperichthys, Hemiancistrus annectens, Hemiancistrus maracaiboensis, Hypostomus panamensis, and Lithoxus, a U-shaped diverticulum in Rhinelepis, Pseudorinelepis, Pogonopoma, and Pogonopomoides; and a ringlike diverticulum in Otocinclus. Scoloplacids, closely related to loricariids, have enlarged, clear, air-filled stomachs similar to that of Lithoxus. The ability to breathe air in Otocinclus was confirmed; the ability of Lithoxus and Scoloplax to breathe air is inferred from morphology. The diverticula of Pogonopomoides and Pogonopoma are similar to swim bladders and may be used as hydrostatic organs. The various modifications of the stomach probably represent characters that define monophyletic clades. The ovaries of Lithoxus were also examined and were shown to have very few (15-17) mature eggs that were large (1.6-2.2 mm) for the small

Molecular Phylogenetics and Evolution of the Cytochrome b Gene in the Cyprinid Genus Lythrurus (Actinopterygii: Cypriniformes)

Abstract: Cytochrome b (cyt b) sequences for eight species of the North American cyprinid genus Lythrurus and two outgroups were analyzed phylogenetically. Species of Lythrurus differed by an average of 10.3% in cyt b nucleotide sequence and exhibited a transition to transversion ratio of 5.44 in pairwise comparisons. Maximum-parsimony and maximum-likelihood analyses support a sister-group relationship between a clade comprised of (L. umbratilis (L. ardens, L. lirus)) and a clade comprised of (L. snelsoni (L. bellus (L. atrapiculus (L. fumeus, L. roseipinnis)))). The phylogeny derived from cyt b sequences has similarities to hypotheses based on morphological evidence but differs substantially in relationships of L. fimeus. The phylogeny indicates a biogeographic scenario that differs from those previously inferred for Lythrurus by suggesting an ancestral divergence between clades that currently occupy largely "northern" and "southern" geographic distributions in the central and southeastern United States. The Ouachita Mountain shiner (L. snelsoni) is sister to species of Lythrurus that now inhabit the Gulf Coastal Plain. This is consistent with earlier hypotheses that Ouachita Highland fauna are at least partially comprised of Gulf Coastal Plain derivatives.

Effects of Experimental Delivery of Male Courtship Pheromones on the Timing of Courtship in a Terrestrial Salamander, Plethodon jordani (Caudata: Plethodontidae)

Abstract: Male courtship pheromones are chemosignals that affect female receptivity. These pheromones are delivered by the male only after a potential mate has been located and initial courtship interactions have commenced (Arnold and Houck, 1982; Houck, 1986). Thus, these pheromones are distinct from sex attractants, which are usually produced by the female and function to bring potential mates together. Courtship pheromones typically are produced by specialized glands that develop only during the breeding season in sexually mature males. These pheromones are present in many arthropods (e.g., Birch, 1974; Boppre, 1984; Grant et al., 1989) but rarely have been reported for vertebrates (Houck, 1986). Salamanders are a notable exception. The use of courtship pheromones by male salamanders is extremely common (Arnold, 1977; Houck, 1980; Houck and Verrell, 1993). Specialized male courtship glands are widespread in salamander species representing all major lineages (Houck and Sever, 1994), indicating that courtship pheromones play an important role in male mating success. Researchers studying courtship behavior and the development of courtship (mental) glands in salamanders have speculated that courtship pheromones functioned to make the female more receptive to the courting male (e.g., Noble, 1931; Arnold, 1976). This premise was tested quantitatively by Houck and Reagan (1990) for a single species of plethodontid salamanders, Desmognathus ocoee (formerly D. ochrophaeus-, see Tilley and Mahoney, 1996). In D. ocoee, courtship pheromones are delivered by a kind of "injection" system: the male pulls his enlarged premaxillary teeth across the female's dorsum at the same time as his courtship gland swabs the area being scraped (see fig. 8 in Arnold and Houck, 1982). The pheromones presumably diffuse into the female's circulatory system via the capillaries that are superficially abundant in this lungless salamander. The target organ stimulated by the pheromones is unknown. Courtship pheromone effects were tested by applying disks of filter paper (saturated in either a pheromone solution or a saline control solution) to female D. ocoee prior to courtship encounters. Houck and Reagan (1990) showed that courtship time was significantly reduced for those pairs in which the female was reated with the pheromone solution. We have extended the generality of these results by addressing the effects of courtship pheromones in Plethodon jordani, a terrestrial salamander having a very different delivery mode. In P. jordani, courtship pheromones are delivered when the male rubs or slaps his mental gland directly on the female's nares (Organ, 1958; Arnold, 1976). Based on work with a related plethodontid salamander (Dawley and Bass, 1988, 1989; Dawley, 1992), we infer that this kind of direct contact results in the delivery of courtship pheromones to the vomeronasal organ and thus to the accessory olfactory system. For other vertebrates, pheromonal stimulation of the accessory olfactory system has been well documented to affect the expression of reproductive behaviors, including increased receptivity (Singer et al., 1986; Rajendren et al., 1990). We tested the hypothesis that, if a P. jordani pair engages in courtship, female receptivity will be increased following the application of male courtship pheromones. Increased receptivity is operationally defined as a reduction in courtship time relative to control values.

Characterization of Microsatellite DNA Loci in American Alligators

Abstract: Microsatellite loci of American alligators were identified from small insert DNA libraries. The average length of microsatellites (18.4 repeats) was similar to that observed in mammals. Polymerase chain reaction (PCR) primers were developed and tested for 20 microsatellite loci that contained at least 10 uninterrupted AC or AG repeats. Genotypes for the 15 loci that could be scored readily were obtained for alligators from Louisiana and Florida. Eleven of the 15 loci were polymorphic. For the polymorphic loci, the number of alleles per locus ranged from 4-17 (average = 8.5), and observed heterozygosity within populations ranged from 0.231-0.865 (average = 0.466). Heterozygosity of these loci is almost 20 times higher than values obtained using isozymes. Populations from Louisiana and Florida differed substantially at these loci (overall FST = 0.137, O, = 0.239, and RST = 0.387). The PCR primers also produced single amplicons from species of Alligatoridae, Gavialidae, and Crocodilidae, indicating that they may be useful for genetic studies in other crocodilians.

Evidence for Phenotypic Plasticity in Snake Body Size and Relative Head Dimensions in Response to Amount and Size of Prey

Abstract: To test whether variation in body size and relative head dimensions may be a phenotypically plastic response to feeding experience in snakes, we assigned neonate water snakes, Nerodia sipedon, from four litters (n = 48) to two feeding treatment groups. One group was offered one large minnow twice weekly; the other group was offered two small minnows twice weekly. Body size (snout-vent length, mass) and head dimensions (head length, head width, jaw length, interocular distance) were measured at the beginning of the experiment and upon completion of the experiment 20 weeks later. Repeated-measures multivariate analysis of variance revealed significant effects of feeding treatment, sex, and family on change in body size. Repeated-measures MANCOVA (with body length as covariate) also revealed a significant effect due to family on change in head dimensions. The multivariate effect of feeding treatment on head dimensions approached statistical significance (P = 0.102); the univariate effect of feeding treatment was significant for jaw length (P = 0.010). Females increased in body size more than males did, and snakes offered large fish increased in body size and jaw length more than snakes offered small fish. These results suggest that body size and jaw length respond plastically to amount and size of prey.

Australian Geckos Do Not Display Diel Variation in Thermoregulatory Behavior

Abstract: Body temperature (Tb) influences almost every aspect of a reptile's physiology and behavior (for reviews, see Huey, 1982; Lillywhite, 1987). For example, Tb can alter both auditory capacity (Werner, 1976, 1983) and locomotory performance (Bennett, 1980, 1990), thus facilitating or impairing escape from and defense against predators (e.g., Christian and Tracy, 1981; Hertz et al., 1982; Goode and Duvall, 1989), prey capture (Greenwald, 1974), and prey handling (Van Damme et al., 1991). Energy available for allocation to growth and reproduction is determined by digestive and metabolic processes, both of which are temperature-dependent (Bennett and Dawson, 1976; Waldschmidt et al., 1986; Van Damme et al., 1991). In viviparous species, the development of offspring depends on the Tb of the gravid mother (Bull, 1980). Thus, Tb can have both direct and indirect consequences for fitness. For many physiological processes (e.g., locomotion, feeding, digestion), the rate of function is maximal over some range of TbS and decreases rapidly above and below this range (Huey, 1982). Field studies of thermoregulation (e.g., Peterson, 1987; Christian and Weavers, 1996) indicate that many reptiles maintain relatively high and constant TbS during activity. Presumably, thermoregulatory behavior allows animals to function over a range of TbS that is conducive to the requisite physiological processes (e.g., locomotion, digestion). However, field TbS do not indicate temperature preference. For many reptiles, tropical environments may provide stable thermal climates such that a narrow range of TbS may be achieved with little effort (Shine and Madsen, 1996). In other cases, individuals may accept TbS that are higher or lower than preferred temperatures due to constraints on their thermoregulation imposed by the environment (Huey and Slatkin, 1976). Clearly, field TbS cannot be strictly interpreted as measures of Tb preferences in reptiles. Preferred body temperature (Licht et al., 1966) has been used as an estimate of body temperature preferences in reptiles. Preferred body temperature (T,) is the Tb maintained by an organism free from all ecological constraints and is measured in a laboratory thermal gradient that provides a full range of equally accessible thermal environments. Measures of T, are useful because they indicate the temperature that n ganism tries to attain during thermoregulation in nature (Hertz et al., 1993). Integrated

Cleaning of coral reef fishes by the wrasse Labroides dimidiatus: Influence of client body size and phylogeny

Abstract: Specialized cleaners remove ectoparasites from apparently cooperating coral reef fishes, This interaction may be a true mutualism, in which both participants benefit, or it may represent a case of exploitation by the cleaners of their clients' response to tactile stimulation. If clients benefit, it is predicted that clients with higher parasite load will seek cleaning more intensely than (and be preferred hy cleaners over) less parasitized clients, We tested for a relationship between client size, usually a reliable predictor of parasite load, and the frequency and duration of inspection by the cleaning wrasse Labroides dimidiatus, among 60 genera (132 species) of coral reef fishes on the Great Barrier Reef. Among species within genera, neither measures of client occurrence on regional reefs nor client size proved consistent predictors of cleaning rates. Using generic values as independent observations, both client size and client regional occurrence correlated positively with the duration and/or the frequency of inspection. However, these relationships disappeared when phylogenetically independent contrasts were used in the analysis, suggesting that the relationships were artifacts of phylogenetic effects. The strength of the associations between cleaners and clients varies among client genera independently of client size or commonness and may reflect the age and coevolutionary history of the different associations.

Origin of Green Turtles, Chelonia mydas, at "Sleeping Rocks" off the Northeast Coast of Nicaragua

Abstract: The largest foraging population of the Atlantic green turtle, Chelonia mydas, occurs in offshore waters of Caribbean Nicaragua (Carr et al., 1978). Green turtles are primarily herbivorous, and the extensive sea grass beds in Nicaraguan waters are utilized both by adults and juveniles (Nietschmann, 1972; Mortimer, 1981; C. Campbell, unpubl. data). Based on tags recovered from adult females, at least two nesting populations contribute individuals to this feeding aggregate: Tortuguero, Costa Rica; and Aves Island, Venezuela (Carr et al., 1978; Sole, 1994). The largest nesting population of Atlantic green turtles is at Tortuguero, which supports an estimated annual nesting of approximately 14,000 females. The second largest nesting colonies in the Caribbean are the Surinam and

Reproductive Cycle and Life-History Traits of the Viviparous Skink Mabuya frenata in Southeastern Brazil

Abstract: The reproductive and fat body cycles and some life-history traits of the viviparous skink Mabuya frenata were studied in a seasonal habitat in the state of Sao Paulo, southeastern Brazil. Reproductive activity is markedly cyclical in both sexes. Females reach sexual maturity at juvenile body sizes, have an extended gestation period lasting 9-12 months, and give birth to 2-8 young (mean 4.9 ? 1.1), mainly during August through October. Fat stored in fat bodies during the wet season is used up during gestation in females and during increased spermatogenic activity in males. Females reach a larger adult body size than males, but males have relatively larger heads. The reproductive and life-history traits observed for M. frenata are similar to those of other South American Mabuya.

Influence of the Guadalquivir River Basin on mitochondrial DNA evolution of Salamandra salamandra (Caudata: Salamandridae) from southern Spain

Abstract: The western region of the Mediterranean Basin has experienced dramatic physiogeographic changes over the last 23 myr during the Miocene and Pliocene periods (L6pez Martinez, 1989). These geologic changes created a succession of geographic barriers to faunistic exchange, some of which have remained in place to the present, and others of which have been eliminated through time. Geographic barriers are expected to have been a major factor in the evolution of Mediterranean herpetofauna, either by producing divergent lineages through vicariance or by permitting reticulated evolution at times when barrier impact is lessened. In the western Mediterranean, two current barriers for amphibian dispersal have received far more attention than any others: the Strait of Gibraltar, separating southwestern Europe from northwestern Africa (Busack, 1986a); and the Pyrenees, the mountain range separating the Iberian Peninsula from the rest of Europe (Oosterbroek and Arntzen, 1992). Little or no attention has been given to the effect of barriers within the Iberian Peninsula on the local her-

Growth and longevity by skeletochronological analysis in Mantidactylus microtympanum, a rain-forest anuran from southern Madagascar

Abstract: dant bone matrix and lines of arrested growth (LAGs). Conversely, amphibians and reptiles from tropical and subtropical areas, and particularly those inhabiting rain forests with relatively constant environments, are expected to have either ill-defined or no LAGs, since these species presumably have no or scarce interruptions and hence continuous growth. Alternatively, if these species undergo annual patterns of inactivity, then a seasonal pattern of LAGs should be detectable. However, despite the great number of skeletochronological papers recently published on amphibians (Castanet et al., 1993, 1996; Guarino et al., 1995), no one has ever investigated amphibians from tropical rain forests. The aim of this study was to examine skeletochronology in Mantidactylus microtympanum, an endemic anuran from the Malagasy rain forest, and to determine whether this technique was appropriate for estimating age structure of tropical herpetofauna. Blommers-Schlosser (1993) includes M. microtympanum in the subfamily Mantellinae (Ranidae), which is endemic to Madagascar. This large-sized species (snoutvent length up to 100 mm) inhabits rain-forest streams in the southeast of the Grand'Ile, and it is active and visible mainly at night. Males and females differ in some characters, such as belly convexity, biometric ratios, and peculiar structure of cloaca in the female. Both juveniles and adults have a brownish back, although it is mottled in the former. The large size of the species allowed us to perform skeletochronological analysis on phalanges alone and, therefore to mark and release the individuals on the site of

Daily migrations of a coral reef fish in the red sea (gulf of aqaba, israel) : initiation and orientation

Abstract: Brown surgeonfish (Acanthurus nigrofuscus) in the Red Sea near Eilat, Israel, undergo daily migrations of up to 1.5 km to feeding sites throughout the year and to spawning sites during June through August. We investigated, by observation and experimentation, the cues that initiate migrations to spawning and feeding sites. We also examined the possible roles that odors, the sun, electromagnetic detection, and landmarks have in determining the routes fish take to the various sites. Initiation of spawning migrations to one spawning site was correlated to the time of sunrise, sunset, and tidal cycle. Fish feeding north of this same site initiated their migrations simultaneously, whereas those feeding south of the site initiated migrations in order of their distance from the site, from distal to proximal, so as to arrive on the spawning grounds more or less simultaneously. This latter observation, and the fact that group size increased as fish move closer to the spawning site in the south but not the north, indicated that social interactions may also play an important role in initiating migrations in some local groups. We were unable to identify factors that influenced initiation to a second spawning site. Migrations to feeding sites appeared to be initiated by sunrise and sunset. Routes to feeding or spawning sites were not determined by odor, sun compass, or electromagnetic detection. Fish key on specific landmarks during migration, but their reliance on particular landmarks can be reduced if the landmarks were moved more than 6 m from their original location. Although surgeonfish usually followed a sequence of landmarks to particular sites, their ability to navigate to feeding or spawning sites after key landmarks were manipulated suggests that there were redundancies in the cues used.