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Phylogenetic relationships among species of Percina are unresolved. Previous systematic studies of Percina have resulted in the recognition of nine subgenera, diagnosed by external morphological characters. Throughout the history of darter taxonomy characters such as large body size, high meristics, drab coloration, and exploitation of a hyperbenthic habitat have been interpreted as pleisiomorphic. Most species of Percina exhibit these characters, and have been hypothesized to represent the “primitive” lineage of darters. The hypotheses that each of the polytypic subgenera of Percina are monophyletic and that the previously defined primitive characters are pleisiomorphic, have not been investigated with cladistic analyses. In this investigation, complete gene sequences of the mitochondrially encoded cytochrome b were collected from a total of 79 individual specimens, representing nine of 10 percid genera and all 40 species of Percina. Observed patterns of cytochrome b evolution were very similar to those previously reported in other percid fishes. Maximum-parsimony and maximum-likelihood analyses were generally congruent. The majority of subgenera (Percina, Imostoma, Cottogaster, Swainia, and Odontopholis) were recovered as monophyletic in most analyses. The subgenera Alvordius, Hadropterus, and Ericosma were never recovered as monophyletic; however, monophyly of Hadropterus and Ericosma could not be rejected in statistical analyses of maximum-likelihood score differences. As a result of these phylogenetic analyses, a novel classification of Percina species is proposed. The use of subgenera in Percina taxonomy is abandoned in favor of the recognition of monophyletic “species clades.” Reconstruction of character evolution on the hypothesized phylogenetic relationships suggest that previously identified pleisiomorphic character states in darters may actually be derived within Percina. Hypothesis testing of derived and ancestral traits in darters is complicated by uncertainty in ancestral character state reconstruction. Contributing to the lack of confidence in character optimization are inadequate sampling of Etheostoma species, short internal branches on the phylogeny, and a high frequency of character change across the entire diversity of darters.
The common garter snake, Thamnophis sirtalis, is the most widely distributed reptile species in North America. Although multiple paternity has been documented in this species, variation in reproduction and ecology suggests that the frequency of occurrence of multiple paternity may vary. We investigated the occurrence of multiple paternity in snakes on Vancouver Island with the following aims: (1) to detect the occurrence of multiple paternity at this location; (2) to determine whether life-history variation and single versus multiple paternity were associated; and (3) to determine whether local rates of multiple paternity differ in comparison to a previous study of this species. Sixteen females and their offspring were analyzed using three highly polymorphic microsatellite loci. Only six of 16 litters showed direct evidence of multiple paternity. Results also showed evidence of a trade-off between offspring size and number of offspring per litter and that females that were multiply mated generally made a higher reproductive investment than females that were singly mated. Rates of multiple paternity in this study and in the previous study differed and were significantly different when litters of fewer than five offspring were eliminated from the analysis. Although we cannot determine the causes of variation in multiple paternity given our data, we suggest two possible mechanisms, one genetic and one ecological, that may lead to different frequencies of multiple fertilizations in this species.
Inertial suction feeding is known to occur in some sharks, but the sequence and temporal kinematics of head and jaw movements have not been defined. We investigated the feeding kinematics of a suction feeding shark, the nurse shark Ginglymostoma cirratum, to test for differences in the timing and magnitude of feeding components with other shark taxa when sharks were fed pieces of bony fish. Thirteen kinematic variables were measured from high-speed video recordings. Food capture in this species consists of expansive, compressive, and recovery phases, as in most other sharks, but there is little or no cranial elevation. Mean time to maximum gape (32 msec) is the fastest recorded for an elasmobranch fish. Other relatively rapid events include mandibular depression (26 msec), elevation (66 msec), and total bite time (100 msec). Buccal valves assist the unidirectional flow of water into the mouth and out of the gill chambers. Food capture under these experimental conditions appears to be a stereotyped modal action pattern but with significant interindividual variability in timing of kinematic events. Ginglymostoma cirratum exhibits a suite of specializations for inertial suction feeding that include (1) the formation of a small, anteriorly directed mouth that is approximately round and laterally enclosed by modified labial cartilages; (2) small teeth; (3) buccal valves to prevent the backflow of water; and (4) extremely rapid buccal expansion. Sharks that capture food by inertial suction have faster and more stereotyped capture behavior than sharks that primarily ram feed. Inertial suction feeding, which has evolved multiple times in sharks, represents an example of functional convergence with inertial suction feeding bony fishes.
Anolis in the eastern Caribbean islands are hosts to three species of malaria parasite (Plasmodium). Although the parasites are widespread on the islands, little is known about their effects on infected lizards. Presented here is an inventory of some costs suffered by Anolissabanus, the endemic solitary anole of Saba, Netherlands Antilles, when infected with Plasmodiumazurophilum, Plasmodiumfloridense, and an undescribed species of Plasmodium. Parasitemia (parasite density in the blood) for most infections was low for all three Saban parasites. Blood cell composition (percent of immature erythrocytes) and blood hemoglobin were altered by infection (severity varied depending on species of parasite). Not affected by infection were body temperature, proportion of lizards with broken tails, perching location, foraging success, male-male interactions in experimental manipulations, and body color or symmetry in body color. Overall, the three malaria parasites of Saban anoles have lower virulence than other lizard malaria parasites studied (one temperate and two tropical). Theory on the evolution of parasite virulence suggests transmission biology of the parasite may differ for the Saban parasites compared to the other studied species.
Aposematic, toxic dendrobatids have received much attention in recent years, resulting in a greater understanding of their biology and evolution; in contrast, data on natural history, social behavior, and systematics are unavailable for most of the approximately 100 species of Colostethus, one of the basal, nontoxic clades of dendrobatids. We studied reproductive and social behavior in Colostethus caeruleodactylus, a species that occurs in igapó forest in the central Amazonian region of Brazil. Reproduction occurs during the rainy season. Males are territorial and can be distinguished from females and juveniles by bright blue coloration of the fingers. Courtship is prolonged and territoriality may serve to prevent interruptions by other males during this critical time. During courtship, which does not include amplexus, males guide females to rolled or folded leaves that serve as nests on the forest floor. Males continue to call and mate while attending nests, which may have more than one clutch. Tadpoles hatch but unlike other species of Colostethus remain in the nest until igapó forests are flooded late in the rainy season, thus providing the larval habitat. This constraint imposed by the delayed formation of the larval habitat may have implications for the structure of the mating system in this species. More information on social behavior of other species of Colostethus coupled with a reliable phylogeny showing relationships among the species will be necessary to interpret the evolution of reproductive behavior and mating systems in this complex group.
South American gymnotiform electric fishes exhibit sexual dimorphism of shape within species, and divergence of shape among species. Recent collecting in floating vegetation mats near Manaus, Brazil, yielded a remarkable association of female and “normal” males of Apteronotus hasemani plus a series of sexually mature male specimens with greatly hypertrophied snouts and gapes. We argue that these fish represent a single species based on shared distinctive features of morphology and coloration, continuous variation of morphometric characters including allometric and dimorphic facial growth in males, ecological and possible reproductive association, and identity in 16S mt rDNA sequences. The degree of dimorphism shown by the large males greatly exceeds previously known limits of intraspecific variation for A. hasemani. The males with the most extreme snouts and gapes closely approach the holotype of Apteronotus anas that is also a mature male. We conclude that A. anas is based on a large male of A. hasemani; the older-named A. hasemani is the senior synonym.
Despite the potential constraints imposed by cutaneous respiration and nocturnality, some salamanders actively thermoregulate when conditions permit. We measured substrate temperature selection in two species of Desmognathus in a moist thermal gradient in the laboratory. Desmognathus monticola selected significantly higher temperatures than Desmognathus quadramaculatus. Although the substrate temperatures selected by D. quadramaculatus did not vary over time (mean ± 1 SE = 13.6 ± 1.1 C), D. monticola selected significantly higher temperatures at night than during the day. Mean temperatures selected by D. monticola were 14.0 ± 1.5 C from 1200–1600 h and 19.7 ± 1.6 C from 2000–0000 h. This difference in temporal patterns is consistent with field behavior, because D. monticola is more frequently found away from water at night than is D. quadramaculatus.
The Madagascan genus Sauvagella is revised and a new species, Sauvagella robusta, from the Ambomboa River (Sofia drainage) described. Preliminary analysis suggests Sauvagella is an ehiravin and that the pellonuline tribe Ehiravini is monophyletic. The immediate relationships of Sauvagella appear to lie with the single other ehiravin genus from Madagascan waters, Spratellomorpha. Reports of the occurrence of Gilchristella in Madagascan waters are in error.
Yellow-lipped sea kraits (Laticauda colubrina) are large (to 1.5 m, 2 kg) amphibious sea-snakes that forage for eels in tropical oceans but return to land to digest their prey, slough their skins, mate, and lay eggs. During three-month field seasons in two successive years, we quantified various aspects of the behaviur of sea kraits on a small island off the coast of Viti Levu, Fiji. Radiotransmitters were surgically implanted in 16 snakes, and regular surveys were conducted to quantify the times and places of various activities by nontelemetered snakes. The radio-tracked snakes spent equal amounts of time on land versus in the ocean, moving between these two habitats about once every 10 days. Their mean duration of time on land fits well with the time required for sloughing and digestion, as measured in outdoor enclosures. These snakes maintained relatively high and constant body temperatures both while on land and in the water; the only overt thermoregulation involved shade-seeking. Different age and sex groups were active in different places and at different times of day. For example, juvenile sea kraits rarely ventured far from water, whereas adults often moved well inland. The snakes moved about at night, engaged in courtship during the morning and were inactive during the afternoon. Thus, snakes were frequently found in courting groups during the morning, but most were solitary at night. Movements between land and sea generally occurred at night on gently sloping areas; movements of adult male snakes also were affected by tidal conditions and by the presence of females. Male sea kraits move about more frequently and actively on land than do females, in keeping with sex differences in locomotor performance.
Hypancistrus inspector, a new species of suckermouth armored catfish from Venezuela, is described and compared to the only other species of Hypancistrus, Hypancistrus zebra. The two species differ mainly in coloration with H. inspector dark brown to black with pale yellow to white spots and H. zebra with a boldly contrasting pattern of black and white stripes. Hypancistrus is diagnosed based on the unique presence of a sharply angled adductor palatini crest and two reversals: wide anterior separation of the metapterygoid and lateral ethmoid and the loss of the lateral wall of the metapterygoid channel. Specimens of H. inspector were found to have many seeds in the intestine suggesting that the species is at least partially granivorous.
Dry season movement patterns, home ranges, and activity was studied in a population of pig-nosed turtles (Carettochelys insculpta) in the wet-dry tropics of northern Australia. Compared to other turtles inhabiting lotic habitats, C. insculpta occupied considerably larger home ranges, covering up to 10 km of river. Of previously published factors influencing home range size, low productivity of the (micro) habitat may best explain the extensive home ranges in C. insculpta. Patchiness and low nutrient value of the chief food (aquatic vegetation) of C. insculpta may force turtles to cover large expanses of river to acquire sufficient energy for growth and reproduction. Females were more active, moved farther, and occupied larger home ranges than males. Home ranges of females comprised 1–4 activity centers, many of which were associated with thermal springs. We suggest that females may exhibit increased activity and movements relative to males because of sexual inequality in parental investment, where food is particularly limiting (e.g., in species with biennial reproduction). Biennial reproduction in the population allowed the examination of the influence of reproductive condition on home range size, movements, and activity. Reproductive condition did not influence home range or activity, but gravid turtles moved father between successive sightings than nongravid females. Individual data corroborate these findings, with females moving farther between successive sightings while gravid compared to while spent. Contrary to previous reports, turtles did not appear to move into estuarine areas or lowland floodplains during the wet season but moved into the riparian forest and possibly into wetlands adjacent to the main channel in the vicinity of their dry season home ranges.
The freshwater goby, Odontobutis hikimius n. sp., is described based on specimens collected from Shimane Prefecture, Japan. The species is unique among Odontobutis in having a connection between the transverse and longitudinal sensory papillae rows on the opercle. It is also distinguishable from congeners by the following combination of characteristics: only a short sensory canal present posterodorsally to eye, lateral scale rows 38–49. Diagnosis of the genus Odontobutis is revised and a key to the seven known species is provided.
We used electromyography (EMG) to investigate bite force production and feeding behavior in five individuals of the teiid lizard, Tupinambis teguixin. Three jaw adductor muscles were tested: pseudotemporalis superficialis (PST), adductor mandibulae externus superficialis (AMES) and pterygoideus (PTY). Force transducer tests determined that mean peak bite force in males (n = 3) was 79 N (22–105 N; n = 24). In females (n = 2), mean peak bite force was 60 N (14–90 N; n = 19). During high-intensity bites, the three muscles tested exhibited synchronous activation patterns, and these activities began before the onset of measured bite forces. Motor activities typically ceased at one-half of the total bite force duration. During natural feeding trials, initial capture bites and crushing bites exhibited motor activity patterns in all three muscles and were similar to those observed during high bite force development. In bites in which the lizards were picking up or moving prey, only the AMES exhibited motor activity. During prey processing, bites were observed that served to position the prey within the jaws and transport it to the esophagus. These bites were accompanied by activity in the AMES and PTY. In some cases, the latter bites were accompanied by activity in the PST. We concluded the AMES is active in all jaw closures. The PTY and PST are sequentially recruited to increase bite forces.
Ptychochromis inornatus, n. sp., is described from the Ankofia basin, northwestern Madagascar. The new species is diagnosed from congeners by the absence of large, black midlateral blotches or bars, and the presence of only two rows of teeth on the second pharyngobranchial toothplate, a robust uncinate process of the first epibranchial bone that is at least twice the diameter of the anterior arm, anterior chest scales that are reduced in size and embedded, a rounded and truncate postero-dorsal margin on the supraoccipital crest, and red fin coloration in life. Ptychochromis inornatus is endemic to the Ankofia drainage basin, with a geographic range extending from the Anjingo River northward to Lake Andrapongy and its surrounding drainages. Intrageneric variation within Ptychochromis is also discussed and comparisons made to the new species.
A new species of slender blind snake, Leptotyphlops alfredschmidti, is described from two localities (2940 and 3090 m) from the western Andean slopes of central Peru (Departamento de Ancash, Provincia de Huarmey). Leptotyphlops alfredschmidti is referred to the Leptotyphlops tesselatus group. The new species shares with Leptotyphlops teaguei and Leptotyphlops tricolor a tricolor body pattern of red, black, and yellowish longitudinal stripes but differs from all members of the group in several features of coloration pattern and pholidosis.
A new species of electric ray, Narcine oculifera, is described from four adult and three fetal specimens collected from the gulfs of Oman and Aden. Narcine oculifera is distinguished from all other species of the genus by its unique dorsal color pattern, composed of irregular light brown to reddish-brown reticulations over disc, pelvic fins and tail, demarcating white or creamy-white oval, reniform and circular spots of variable sizes, and with small white spots on dorsal and caudal fins. Narcine oculifera resembles an undescribed species of Narcine from the western coast of Madagascar, with which it is compared. The new species described here was collected from two localities off Oman and from two off Somalia and represents only the second species of Narcine from the western Indian Ocean.
A new species of the cichlid genus Pseudotropheus Regan (Teleostei: Cichlidae), from Lake Malawi is described. The new species is a member of the Pseudotropheus williamsi complex from Mbenji Island. Pseudotropheus williamsi is the type species of the genus Pseudotropheus, which is a polyphyletic grouping of several species of rock-dwelling cichlids from Lake Malawi. In addition to the P. williamsi complex, Pseudotropheus contains species belonging to the P. tropheops, P. elongatus, and Pseudotropheus aggressive complexes, as well as a group of miscellaneous forms such as Pseudotropheus fainzilberi. We predict that Pseudotropheus eventually will be restricted taxonomically to include only members of the P. williamsi complex, but because of the lack of phylogenetic data on many of the miscellaneous forms (e.g., P. fainzilberi) we are currently unable to diagnose Pseudotropheus as monophyletic.
Listrura tetraradiata, new species, is described from a small headwater stream of the Lagoa de Araruama system, a coastal lagoon system in Rio de Janeiro state, southeastern Brazil. It is easily distinguished from other species of the genus by having four pectoral fin rays (vs three in Listrura camposi and one in Listrura nematopteryx) and branched rays in pectoral, dorsal and anal fins, these character states unique among glanapterygines. It also differs from its congeners by higher number of premaxillary and dentary teeth and fewer number of procurrent caudal fin rays.
Colostethus marchesianus was described from Missão Taracuá in Amazonas, Brazil, in 1941. Two specimens were collected in 1924 by Douglas Melin, a Swedish naturalist who led an expedition to the site. The name Colostethus marchesianus has since been applied to many populations of frogs in Amazonian Brazil, Colombia, Ecuador, Peru, and Bolivia. The type specimens are in poor condition; in addition, tadpoles, calls, and reproductive data were not obtained at the time of collection of the original specimens. Tadpoles and calls are critical in helping distinguish among morphologically similar species. Differences in morphology and calls from various widespread populations have led us and other workers to conclude that populations currently referred to as C. marchesianus represent a number of similar species. With the objective of obtaining adult frogs for redescription, tadpoles, and calls, two of us visited the type locality in April and May 2000. Only one species of Colostethus was present in the area. We obtained adults and recordings of the call and raised tadpoles (described elsewhere) taken from the backs of parent frogs. Colostethusmarchesianus from the type locality differs from specimens from Colombia, Venezuela, Ecuador, and Peru based on a variety of characters described in the literature. Thus, frogs from those localities appear not to be the same species as C. marchesianus. The detailed redescription provided herein should help future workers distinguish populations of similar species from C. marchesianus.
Tadpoles of two closely related Amazonian species of Colostethus are described. Colostethus marchesianus was described by Melin in 1941 from Missão Taracuá, Rio Uaupés, Amazonas, Brazil, and has been depicted as widely occurring throughout the Amazon region; Melin did not describe the tadpoles of this species. Subsequent descriptions of the tadpole of C. marchesianus have been based on specimens from Ecuador, Peru, and from north of the Amazon River in Amazonas, Brazil. However, variation among populations referred to as C. marchesianus has indicated that this taxon may actually be a complex of undescribed species. We revisited the type locality to obtain specimens of C. marchesianus with the objective of redescribing the adult and describing the tadpole for the first time. We also obtained tadpoles of a recently described species, Colostethus caeruleodactylus, that occurs south of the Amazon River in Amazonas, Brazil, and is similar to C. marchesianus. Tadpoles of the two species can be separated from each other based on the reduced number of tooth rows and other features of the oral disc. We suggest that size, arrangement, and number of papillae may be a synapomorphy uniting members of a clade consisting of C. marchesianus and C. caeruleodactylus and possibly closely related species whose tadpoles are unknown at present.
This study presents details of the ultrastructure of the spermatozeugmata and spermatozoa of the South American catfish, Trachelyopterus lucenai, an inseminating species. Spermatozoa are tightly packaged into unencapsulated bundles, spermatozeugmata, with as many as 130 cells comprising a single packet. Within an individual spermatozeugma, cells are aligned side by side such that the anterior region of the bundle is comprised of nuclei, the middle region midpieces, and the posterior region flagella. Integrity of the packet appears to be maintained by specialized junctions between adjacent cells along their entire lengths. Each spermatozoon is characterized by an elongate nucleus containing condensed chromatin and a fossa at the posterior end. The elongate midpiece contains multiple mitochondria, abundant glycogen deposits, and accessory microtubules that run along the length of the midpiece. The ultrastructural modifications of the spermatozoa are discussed as possible adaptations associated with the reproductive mode of insemination.
The larvae of spadefoot toads exhibit extreme developmental/endocrinological diversity. For example, New World spadefoot toads (Scaphiopus and Spea) have the shortest larval periods known among anurans, and the tadpoles of Old World spadefoot taxa (Pelobates) are among the largest known. To analyze the patterns of this diversity in an evolutionary context, we generated comparable larval growth and development data from 10 of the 11 taxa of spadefoot toads and from one taxon of parsley frog (Pelodytes), the nearest spadefoot toad relative. We found dramatic differences in growth and development among taxa, which indicated that taxon-specific physiology, rather than phenotypic plasticity, underlies larval period diversity. For all eight response variables (development rate, three growth rates, time to forelimb emergence, time to tail resorption, mass at tail resorption, and body length at tail resorption), taxa within genera were similar to each other and were different from taxa in other genera. Larvae of Scaphiopus were small with short larval periods, larvae of Spea were large with short larval periods, larvae of Pelobates were large with long larval periods, and larvae of Pelodytes were small with long larval periods. Even though taxa within the same genus live in different environments, larval growth and development correlated with phylogenetic groupings rather than breeding habitat. Mapping larval data onto a molecular phylogeny indicated that short larval periods, as well as rapid embryonic development and high temperature tolerance, originated within the spadefoot toad family.
The topminnow Aplocheilus lineatus detects and localizes the source of water surface waves with its cephalic lateral line system. Previous behavioral experiments with Aplocheilus have been performed with blinded animals. We tested how well sighted Aplocheilus can be trained to discriminate between water surface waves of different frequency and duration and whether the animals used information from the lateral line for discrimination. Our data show that sighted topminnows can be trained to respond to and discriminate between single-frequency water surface waves and that lateral line information is required for the discrimination. Thus, blinding the animals by surgically removing the eyes in many cases is probably not a necessary prerequisite for testing the sensory capabilities of the lateral line in surface-feeding Aplocheilus.
Venomous snakes are often perceived as aggressive antagonists, with the North American cottonmouth having a particularly notorious reputation for such villainy. We designed tests to measure the suite of behavioral responses by free-ranging cottonmouths to encounters with humans. When confronted, 23 (51%) of 45 tested tried to escape, and 28 (78%) of 36 tested used threat displays and other defensive tactics; only 13 of 36 cottonmouths bit an artificial hand used in the tests. Our findings challenge conventional wisdom about aggressive behavior in an animal perceived as more dangerous than it is. Changing irrational negative attitudes about venomous snakes is a necessary step toward quelling the recently documented global decline in reptiles.
The behavioral significance of color patterns has been widely investigated in cichlid fishes (Perciformes; Cichlidae), whereas the ontogeny of cichlid color patterns has received less attention. We examined the ontogeny of melanistic pattern elements in the convict cichlid, Cichlasoma nigrofasciatum. Live juvenile convict cichlids, from hatching through age 88 days, were photographed using a dissecting microscope. Based upon this photographic record, we have characterized the sequential, intermediate phases of color pattern development in the convict cichlid. Convict cichlid fry hatch three days postfertilization with (horizontal) stripes and diffuse cranial and ventral chromatophores. Vertical bars develop gradually and are initiated as midlaterally incomplete semibars. This pigment pattern ontogeny appears similar to some, but not all, previously characterized cichlids.
The most primitive frogs in which a sex chromosome system has been determined are members of the endemic New Zealand genus Leiopelma. Two species, Leiopelma pakeka and Leiopelma hochstetteri, have female heterogamety of the ZW/ZZ and 0W/00 types, respectively. Despite its great karyotypic similarity to L. pakeka, a third species, Leiopelma archeyi, has not been know previously to possess heteromorphic sex chromosomes. Herein a highly differentiated putative W chromosome characterized by the addition of a completely heterochromatic short arm is reported from a female L.archeyi from the Whareorino forest of the North Island of New Zealand.
The existence of both interspecific and intraspecific morphological and anatomical variation in vertebral intercentra is described for the first time in Lacertidae. A sample of 380 cleared-and-stained specimens of 12 species of lacertid lizards reveals also the presence of thoracolumbar intercentra in Lacertidae, a condition previously reported within Squamata only for the families Xantusiidae and Gekkonidae. The significance of these findings in the context of phylogenetic analyses within Squamata is discussed.
Comparative osteological studies of the sturgeon genus Acipenser are rare. In this paper, the rostral canal bones of Acipenser brevirostrum and Acipenser oxyrinchus oxyrinchus are compared and three new osteological features that distinguish these species are described. In lateral view, the jugal bone of adult A. o. oxyrinchus possesses distinct vertical and horizontal arms, whereas that of A. brevirostrum is roughly triangular in shape. The posterior rostral canal bones in A. o. oxyrinchus possess larger and more pointed medial expansions relative to those found in A. brevirostrum. The rostral canal bones immediately lateral to the commissure in adult A. o. oxyrinchus are ornamented with thorn-shaped processes, which differ from the simple Y-shaped tubes found in A. brevirostrum and other taxa examined.
The effect of water dynamics is well known for some aspects of turtle biology, particularly for egg incubation. The role water plays during migration from the nest to the aquatic environment, however, is not well understood. To evaluate water loss and movement patterns of hatchling turtles during migration, we conducted an experimental release of 463 hatchling snapping turtles, Chelydra serpentina, under ecologically relevant field conditions. We recaptured 62.9% of hatchlings released, and 90% of these were caught during the first four days following release. Hatchlings migrating for less time lost more water than those migrating for a longer time; changes in water content ranged from 1.2% to −4.7%. Mean air temperature during the recapture interval was positively correlated with water loss. Furthermore, hatchlings lost significantly more water when recaptured during periods with no rainfall compared to intervals with rainfall (14.5% and 8.3% water loss, respectively). Additionally, more hatchlings were recaptured during precipitation events and intervals with intermediate mean air temperatures. Alternative strategies for migration may exist such that some hatchlings move quickly to the water, minimizing exposure to predators, but increasing water loss and risk of desiccation. Other hatchlings may wait for optimal weather conditions (i.e., moderate air temperatures and precipitation), increasing exposure to predators, but limiting water loss. Further studies are needed to elucidate the relative risks and benefits associated with each strategy.
The black salamander, Salamandra lanzai, exists in isolated and fragmented populations in the Cottian Alps. To examine the degree of intra- and interpopulation divergence, mitochondrial cytochrome b sequences were obtained from samples representing all populations of S. lanzai. No genetic variation was observed either within or among populations. The presence of a single lineage suggests historical explanations closely related to Pleistocene events.
Comparisons of the holotype of Plectranthiaslamillai Rojas and Pequeño, 1998, collected off the Juan Fernández Islands off the coast of Chile, with type and nontype material of another eastern South Pacific species, PlectranthiasexsulHeemstra and Anderson, 1983, show that the differences between the two nominal taxa reported by Rojas and Pequeño are not great enough to warrant recognition of two distinct species. Accordingly, we consider P. lamillai to be a junior synonym of P. exsul.
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