The phylogenetic relationships among all but one horned lizard species were inferred from mitochondrial ribosomal rRNA gene sequences (251 bp of 12S and 457 bp of 16S) and morphology (32 informative characters). Phylogenies were reconstructed based on separate and combined analyses using parsimony and maximum-likelihood methods. The separate mtDNA and morphological hypotheses were largely incongruent. Bootstrap analyses suggested that most of the incongruence was the result of weak support (bootstraps <70%) for alternative relationships (e.g., placement of Phrynosoma asio). However, there were strongly supported alternative placements of Phrynosoma ditmarsi. Mitochondrial DNA strongly placed P. ditmarsi with the short-horned lizards (i.e., Phrynosoma orbiculare and Phrynosoma douglasi sensu lato), whereas morphology strongly supported its exclusion from the large clade containing the short-horned lizards and placed P. ditmarsi with the southern Phrynosoma braconnieri Phrynosoma taurus. Various consensus methods for assessing topological congruence (= taxonomic congruence) between the separate phylogenies indicate little congruence (i.e., strict consensus) or misleading congruence (i.e., Adam's consensus). Also, although bootstrap analyses suggested strong incongruence only involving the placement of P. ditmarsi, the Wilcoxon signed-ranks test suggests the incongruence between datasets is significant, even when P. ditmarsi is pruned from the trees. Combined analysis of the mtDNA and morphological data resulted in a single most-parsimonious tree. All resolved clades, except two, were also discovered in the separate analyses of mtDNA or morphology.

The New World clade of needlefishes (Belonidae) includes species distributed along the Pacific and Atlantic coasts of the Americas and in freshwater basins of Central and South America. Phylogenetic relationships among 13 species of the group were assessed based on data from two nuclear genes (RAG2 and Tmo-4C4), two mitochondrial genes (cytochrome b and 16S rRNA), and a small suite of morphological characters. In general, there was concordance between separate analyses of nuclear and mitochondrial characters, and RAG2 was found to be a particularly useful gene for phylogeny reconstruction. Morphology supported an alternative phylogenetic pattern, but this was probably a result of the small number of characters and the lack of a thorough anatomical survey. The total evidence hypothesis divides the group into two major clades. In one, Pseudotylosurus from freshwater in South America is most closely related to a pair of Strongylura species from the western and eastern Atlantic; in the other, Potamorrhaphis and Belonion from South American freshwater are related to a clade of Strongylura from marine and freshwater habitats of the eastern Pacific and western Atlantic. Optimization of habitat on the total evidence tree, combined with paleogeographic data, suggests that four independent entries into freshwater have taken place—one in Central America, and three in South America.

Remnant populations of leopard frogs within the Virgin River drainage and adjacent portions of the Colorado River (Black Canyon) in northwestern Arizona and southern Nevada either represent the reportedly extinct taxon Rana onca or northern, disjunct Rana yavapaiensis. To determine the evolutionary distinctiveness of these leopard frogs, we evaluated mitochondrial DNA (mtDNA) restriction site variation (RFLP), mtDNA control region sequences, randomly amplified polymorphic DNA (RAPD) markers, and morphological characters. Individuals from the Virgin River drainage and Black Canyon represented a single RFLP haplotype and were identical for nucleotides along a portion of control region sequence. Evaluations of RAPD data demonstrated high levels of similarity among individuals and populations from this region. Leopard frogs from the Virgin River drainage and Black Canyon differed from R. yavapaiensis from west-central Arizona and northern Mexico in maximum parsimony and distance analyses of RFLP and control region sequence data and in maximum-likelihood analysis of the sequence data. Multidimensional scaling of RAPD data provided a similar and congruent indication of this separation. Analysis of principal component scores demonstrated significant morphological differentiation between leopard frog specimens from the Virgin River drainage and R. yavapaiensis. Parallel patterns of divergence observed in the mtDNA, RAPD, and morphological analyses indicate that leopard frogs from the Virgin River drainage and adjacent portions of the Colorado River are phylogenetically distinct. These leopard frogs should be recognized as a lineage separate from southern populations of R. yavapaiensis and classified as the species R. onca.

Swordtails in the genus Xiphophorus exhibit substantial variation in male body size influenced by genetic variation at the pituitary (P) locus on the Y-chromosome. However, males of Xiphophorus pygmaeus have historically been classified as uniformly small; they were thought to possess one of two P-alleles, both for small size. In 1988, large male X. pygmaeus were discovered at two sites in the Río Huichihuayán, Mexico. Surprisingly, females from these sites have lost the ancestral preference for large males although females from adjacent sites have not. This study investigates the heritability of large body size in male X. pygmaeus to understand its role in the evolution of male mating strategies and female preference in this species. We conducted breeding experiments with X. pygmaeus from two populations to determine whether large size is influenced by the same P-allele system found in other swordtails. Small fathers had a significant effect on the size at maturity of their sons but large fathers did not. All sons were small in size regardless of paternal size. Large fathers were no more successful than small fathers in producing offspring, and we found no significant relationship between age at maturity and size at maturity of the sons. In some cases, there was a significant difference in prematuration growth rate of sons between populations and in postmaturation growth rates within and between populations, yet all sons remained small in size. These results suggest large size is not paternally heritable through a P-allele in this species but could be a result of changes in pre- or postmaturation growth rates. The evolutionary persistence and spread of large male size may not follow current models of sexual selection on P-alleles and the loss of female preference in one population may be explained by the apparent lack of heritability of this male trait.

Animals held in the unnatural surroundings of the laboratory sometimes may exhibit unusual behavior, making experimental results difficult to interpret unless the natural history of the species is well understood. Some well-studied species, such as the garter snake Thamnophis sirtalis, which usually seem to adapt well to captivity, are therefore commonly used in laboratory experiments and assumed to function normally. However, this assumption may sometimes be unfounded. In this study, captive gravid T. sirtalis showed reduced feeding behavior, similar to free-ranging gravid snakes from the same population but showed very different thermoregulatory behavior, choosing low temperatures instead of high. By contrast, gravid congeners, Thamnophis elegans, showed similar feeding and thermoregulatory behavior in captivity and in the field. Choice of lower temperature by gravid T. sirtalis apparently led to extended periods of parturition for individual females and a high incidence of dead young in litters. Other studies of T. sirtalis in captivity also have yielded fairly high proportions of dead offspring, suggesting that (1) this species has a relatively high background rate of natural stillbirth; and/or (2) it is not always as suitable a species for behavioral/reproductive work in the laboratory as it seems to be. Whether or not the first proposition is true, I conclude that T. sirtalis in this study behaved differently from snakes in the field, exacerbating the rate of stillbirth. Thus, laboratory studies of behavior will be most fruitful if informed by field studies.

Osteoglossomorpha were first defined on the basis of two characters: (1) the parasphenoid-tongue bite apparatus (TBA); and (2) the presence of processes associated with the second hypobranchial and/or basibranchial element of the ventral gill arches. These two characters have continued to be cited as unambiguous support of the monophyly of this group of basal teleostean fishes. The TBA has been vaguely defined as a “bite” of gill arch dentition against that of the parasphenoid and palatoquadrate bones. Historical definitions include both plesiomorphic (e.g., enlarged teeth on palatoquadrate bones and gill arches) and apomorphic (e.g., enlarged teeth on the parasphenoid and a direct connection between the sternohyoideus muscle and the ventral gill arch skeleton) character states. Also, the processes associated with the second gill arches are likely components of the osteoglossomorph TBA by providing an additional attachment surface for the sternohyoideus (i.e., in addition to the sternohyoideus-urohyal connection). There is variation both of presence and form of these processes within osteoglossomorphs. To use both the presence or absence of a TBA as well as its component characters in systematic analyses artificially weights the value of this character complex. This character complex should not be used in place of, and especially not in addition to, its component characters.

The taxonomic status of Rana capito is unclear. Allozymes were surveyed for Rana areolata and populations throughout the range of R. capito, including representatives of the three putative subspecies. Fixed differences were exhibited at two loci, supporting the separation of R. capito and R. areolata. The westernmost population of R. capito, in the range of Rana capito sevosa, could be diagnosed from the remaining populations of R. capito. These remaining populations exhibited no substantial genetic divisions. We recommend the resurrection of R. sevosa as a distinct taxon.

Video images of 215 adult Gila robusta and 148 endangered Gila cypha were collected from May 1991–October 1992 at eight Colorado River basin localities (seven upper basins and one lower basin). The two species were sympatric at five of these locations; G. robusta was absent at one site, whereas G. cypha was missing at two others. Saggital views of each individual were videotaped and 25 morphological points (15 anatomical landmarks and 10 helping points) identified. Bookstein shape coordinates were calculated from Cartesian coordinates of these landmarks and points, whereas centroid size was used as a measure of body size. Shape differences were evaluated among populations of each species using MANOVA and canonical variates analysis. In G. cypha, variation encompassed three aspects: nuchal hump (most pronounced in Grand Canyon forms), relative head size (larger in Cataract Canyon forms), and caudal peduncle dimensions (shorter with a tapering depth in Cataract Canyon forms but longer and uniformly deeper in those from Desolation Canyon). Nuchal development in G. robusta is slight, hence only head and peduncle dimensions distinguished populations. Those individuals from Cataract Canyon had relatively shorter peduncles that (again) tapered in depth from anterior to posterior, whereas G. robusta from Desolation Canyon possessed peduncles that were much longer and of uniform depth. Specimens from Debeque and Rifle Canyons had proportionally smaller heads. Variation among all 13 populations (i.e., both species together) was evaluated using relative warp analysis, with G. cypha and G. robusta clearly separated at all sympatric locations except those from Desolation and Caratact Canyons. Here, body shapes of the two species converged. Overall, shape variation in both species is clinal. Although results from our geometric morphometric analysis were statistically similar to those based on distances derived from a truss analysis, the geometric approach visually demonstrated phenotypic differences among populations and species and this, in turn, has management implications.

We studied the ecology of Anolis nitens tandai at three localities in the central and western Amazon of Brazil. The lizards were largely restricted to leaf litter microhabitats in relatively undisturbed rain forest. Activity occurred throughout the day. Body temperatures of active lizards averaged 27.7 ± 0.3 C and were similar to air and substratum temperatures in the microhabitats in which lizards were found. Microhabitats containing lizards were slightly warmer than a random set of microhabitats suggesting that the lizards selected relatively warm sites within a relatively cool forest habitat, but avoidance of treefalls suggests lizards do not seek out the warmest available microhabitats. The diet consisted mostly of grasshoppers, crickets, spiders, and insect larvae. Mean prey size increased with lizard body size, and lizards varied in how full their stomachs were. Sexual dimorphism in mass and limb length exists. Compared with other subspecies of Anolis nitens, A. n. tandai has relatively longer limbs than Anolis nitens scypheus or Anolis nitens nitens and intermediate body temperatures.

Estudou-se a ecologia de Anolis nitens tandai em três localidades da Amazônia brasileira central e ocidental. Os referidos lagartos foram encontrados principalmente em microhabitats do folhiço, em floresta úmida relativamente não perturbada. Apresentaram-se ativos durante todo o dia, com uma temperatura corporal média de 27,7 ± 0,3 C, similar às temperaturas do ar e do substrato no microhabitat onde se encontravam. As temperaturas nos microhabitats contendo lagartos mostrou-se ligeiramente mais elevada que a de uma amostra aleatória de microhabitats, sugerindo que os lagartos procuram locais relativamente quentes em meio a um habitat florestal relativamente frio. Contudo, o fato de que evitam clareiras causadas pela queda de árvores sugere que eles não procuram os microhabitats mais quentes disponíveis. Dimorfismo sexual quanto à massa corporal e comprimento dos membros locomotores existe. A dieta consistiu principalmente de gafanhotos, grilos, aranhas e larvas de insetos. O tamanho médio da presa aumentou com o tamanho do corpo do lagarto, e os lagartos variaram com relação à quantidade de alimento encontrada nos estômagos. Em comparação a outras subespécies de Anolis nitens, A. n. tandai apresenta membros locomotores relativamente mais longos que Anolis nitens scypheus ou Anolis nitens nitens, e temperaturas corporais intermediárias.

The Topeka shiner Notropis topeka has declined in abundance throughout its historical range in the central U.S. As a result, this minnow was listed as federally endangered in 1999. The objective of our study was to quantitatively assess instream physical, chemical, and biological parameters and landscape-level factors influencing the distribution (i.e., extant or extirpated) of Topeka shiners. We sampled 26 streams in the Flint Hills region of Kansas: 12 sites where Topeka shiners are extant; and 14 sites where they are extirpated. Multivariate analysis of variance was used to test whether variables were different between extant and extirpated sites. Mean catch per effort of largemouth bass in stream pools was higher at extirpated sites, and species diversity by trophic guild and richness in stream pools were higher at extirpated sites. Stepwise logistic regression was used to develop a model to predict whether Topeka shiners were extant or extirpated. Number of small impoundments per watershed area, catch per effort of largemouth bass Micropterus salmoides in pools, and length of pool were the only significant variables in the logistic model. Our model correctly classified 83% of extant sites and 85% of extirpated sites. In a landscape-level analysis of 111 streams, only number of small impoundments per watershed area was significant in the logistic model. These results provide predictive tools to assess instream and landscape-level characteristics for habitat management and possible reintroduction of Topeka shiners in Kansas Flint Hills streams.

Objectives of this study were to determine whether (1) stream algal biomass was nutrient limited, (2) stream herbivores could reduce algal biomass at different levels of productivity, and (3) a large vertebrate herbivore (Ascaphus truei) affected the abundance of insect grazers under different nutrient supply regimes. To address these objectives, we conducted a 2 × 2 factorial experiment to examine the effects of varying phosphate supply on periphyton biomass, insect grazers, and a tadpole grazer in 12 streamside experimental channels in southwestern Canada. We manipulated presence of tailed frog tadpoles (A. truei Stejneger) and varied nutrient levels using nutrient-diffusing pellets. We monitored periphyton biomass as ash-free dry mass (AFDM), insect grazer abundance, dissolved nutrients (NO₃ − N and PO₄ − P) in water, and tadpole growth rates over 38 days. Dissolved nitrate and phosphate concentrations were temporally variable, and there were no statistical differences among treatments, but dissolved phosphate levels were 1.7 times greater in nutrient-enriched channels (3.2 µg L⁻¹) than in unenriched channels (1.7 µg L⁻¹). Periphyton AFDM was significantly higher in channels with added nutrients, as was abundance of insect grazers, primarily Chironomidae and Ephemeroptera. Tadpoles in channels with nutrients had growth rates approximately four times higher than tadpoles in controls. Insect grazer abundance in channels with and without added nutrients was lower in the presence of tadpoles, and this reduction was greater in channels with nutrients. In contrast to other studies that have examined the impact of vertebrate herbivores on periphyton, tadpoles had no measurable effect on periphyton biomass. These data indicate periphyton and grazers were resource limited, as added nutrients increased periphyton biomass, as well as abundance (insect grazers) and biomass (tailed frog tadpoles) of herbivores.

The swimbladders of physostomous Brevoortia tyrannus (Atlantic menhaden) and physoclistous Leiostomus xanthurus (spot) develop as a simple evagination of the larval foregut. The swimbladder of L. xanthurus develops earlier (at yolk and oil globule depletion when larvae are two days posthatch and ∼2 mm notochord length) than it does in B. tyrannus (well after yolk and oil depletion when larvae are 12 days and ∼8 mm). The larvae of each species initially inflate the swimbladder by ascending to the surface and forcing atmospheric gas through a pneumatic duct into the swimbladder lumen. Larval B. tyrannus modulate swimbladder volume and buoyancy within a diel cycle by inflation with atmospheric gas passed through a persistent pneumatic duct and deflation by diffusion through the swimbladder wall along with expulsion through the anus and mouth. This capacity of swimbladder volume modulation and buoyancy compensation corresponds with the average vertical distribution of larvae in the sea, where larval B. tyrannus occupy the upper water column. The pneumatic duct of L. xanthurus atrophies after 20 days and has no discernable lumen after 40 days, the beginning of metamorphosis when larvae are ∼7 mm standard length. The mucosal epithelium of the swimbladder of L. xanthurus acquires cytological characteristics of adult gas-gland tissue soon after initial inflation when larvae gain the capability of gas secretion. A plexiform rete mirabile does not form until metamorphosis. The swimbladder of larval L. xanthurus functions by providing neutral buoyancy with low amplitude diel depth changes in swimbladder volume. In the sea, larval L. xanthurus occupy primarily mid- and deep depths.

This paper analyzes data from the published literature with the addition of some new information to explore the relationship between varanid body size and reproductive biology. Incubation time for varanid eggs is positively correlated with egg mass, neonate snout–vent length (SVL), and maximum adult snout–vent length (SVL_max). Incubation period of heavier eggs is proportionally less than for smaller eggs at 30 C. SVL_max is positively correlated with egg mass, clutch size, clutch mass, neonate body mass, and neonate SVL. Neonates of larger species have longer SVL but are smaller as a proportion of SVL_max than for smaller species. Clutch sizes are larger and more variable for larger species; however, clutch sizes for larger species relative to SVL_max are smaller than for smaller species. The intraspecific influence of maternal SVL on clutch size is greater than the interspecific influence of SVL_max on clutch size. These results suggest there are greater fitness advantages for smaller species having relatively larger offspring than for larger species, which concurs with results for snakes and other genera of lizards, as well as optimal offspring size theory. Reproductive output also appears to be influenced by maternal abdominal volume. Analysis of phylogenetically corrected data generally concurs with patterns evident in the nonphylogenetically corrected data. Body size has a much greater influence on reproductive output of Varanus than phylogeny.

Two phenetic complexes are recognized among the small (usually less than 46 mm SL), semitranslucent, red species of the subgenus Apogon lacking stripes, bars, or black edges on scales on body sides, with six spines in first part of dorsal fin and one spine and 8–9 (almost always 9) rays in second part, two anal fin spines and 7–8 (almost always 8) rays, 12–15 pectoral fin rays, and a total of 16 or fewer gillrakers. The Apogon coccineus complex has one large full scale, and often one small scale, between the lateral line and the third spine of the first part of the dorsal fin and a free edge of skin near the anterior nasal opening. Members of the Apogon erythrinus complex have two large full scales, and often a small scale, between the lateral line and dorsal fin and no free edge of skin near the anterior nasal opening. Four species are recognized in the A. erythrinus complex: A. erythrinus, endemic to the Hawaiian Islands and Johnson Island; Apogon marquesensis n. sp., endemic to the Marquesas Islands; Apogon indicus n. sp., ranging from the Indian (where it is the only member present) to the Pacific oceans; and Apogon susanae n. sp., restricted to the Pacific Ocean.

We describe the reproductive biology of northern populations of Crotalus willardi using data gathered from four long-term field studies, histological examination of museum specimens, and literature records. Spermiogenesis occurs summer to early autumn. All male C. willardi examined contained sperm in the vas deferens (June–September) and had enlarged kidney sexual segments (June–October). Parturition occurs from late July through August (n = 17). Postpartum females appear to remain reproductively inactive prior to hibernation. Secondary yolk deposition (vitellogenesis) commences in the late spring or early summer, one or more years after parturition. Ovulation and fertilization probably occur early in the spring, followed by 4–5 months gestation. Copulation occurs in midsummer to early fall (n = 10). Repeated observations of marked females over several years, proportion of adult gravid females (60% Crotalus willardi obscurus, 40% Crotalus willardi willardi, 51% pooled), observations on captive animals, and histological observations collectively suggest frequency of reproduction is facultative but typically biennial or longer in wild snakes. Litter size averaged 5.4 ± 1.6 SD (n = 25, range 2–9). Regression analysis of 20 litters revealed an allometric relationship where litter size increased as an approximately cubic function of maternal SVL (litter size = e^−14.64 SVL^2.66). Forty-two neonates measured 167.2 ± 7.4 mm SD (range 150–182) and 43 neonates weighed 6.8 ± 1.2 g SD (range 5.0–9.0). The shortest reproductively active specimens measured 406 mm (male) and 402 mm (female) SVL.

Bedotia masoala, a new species of Malagasy rainbowfish, is described from the Ankavanana drainage on the eastern slope of the Masoala Peninsula, northeastern Madagascar. The new species is readily distinguished from congeners by a unique blotchy, mottled, or barred lateral pigmentation pattern, and further distinguished from Bedotia marojejy, the only additional Bedotia that lacks a prominent, solid, dark midlateral stripe, by a higher vertebral count, a greater number of scales in lateral series on the flanks, and by the presence of palatine and well–developed endopterygoid tooth patches. Bedotia masoala is endemic to the Ankavanana drainage, an eastward flowing basin of the Masoala Peninsula.

The question of whether lizards possess a sense of taste and are able to use it to discriminate between prey items has been debated in the literature for several decades. This study provides evidence that some lizards indeed do use gustation to discriminate between prey items. In laboratory choice experiments, the lizard Anolis carolinensis discriminated between untreated crickets and crickets treated with either dextrose/aspartame powder (produces sweet sensation in humans) or quinine hydrochloride (QHCl) solution or powder (bitter sensation in humans). Although some of the lizards showed a strong preference for crickets treated with dextrose/aspartame powder, all lizards generally avoided prey items treated with QHCl. This avoidance is not affected when access to the vomeronasal organ is blocked. During this study, lizards readily associated taste with color.

A new species of clingfish is described from the shallow marine waters of the Philippines. This brings the number of species in the the genus to 10, all of them found in the tropical to warm-temperate waters of the Indo-West Pacific Ocean.

A new species of Apostolepis is described from Izozog in the Gran Chaco of Santa Cruz, Bolivia. It and Apostolepis dorbignyi are the only species known from the Gran Chaco morphoclimatic domain. The new species is one of the most distinctive members of the genus and can be easily distinguished from all congeners by a unique suite of characteristics. Only the third supralabial enters the orbit, and this characteristic is unknown in other elapomorphines. The new species and A. vittata share several apomorphic characters, and these species are hypothesized to be each other's closest relative.

Se describe una nueva especie del género Apostolepis de la región de Izozog en el Gran Chaco de Santa Cruz, Bolivia; ésta y Apostolepis dorbignyi son las únicas especies del género conocidas en el dominio morfoclimático del Gran Chaco. La nueva especie posee una serie única de caracteres que la hacen muy distinta y fácilmente diferenciable de las otras especies del género. Sólo la tercera supralabial entra en el ojo, una característica inexistente en otros elapomorfinos. La nueva especiey A. vittata comparten varios caracteres apomórficos por lo que se hipotetiza que son las más estrechamente relacionadas entre sí.

We sequenced a 307-bp fragment of the mitochondrial cytochrome b gene from 42 individuals representing 14 populations of the western terrestrial garter snake, Thamnophis elegans. Current taxonomy recognizes either five or six subspecies of T. elegans based on color and scale morphology, but all agree on three major geographic races (T. e. elegans, terrestris, and vagrans). Although the cytochrome b phylogeny did not match subspecific classification of the populations, it did yield geographically proximate groups. Populations from the Sierra Nevada range and Monterey, California, formed one monophyletic group of T. e. elegans and T. e. terrestris. This Sierran/Monterey group was included in a larger group with eastern populations from the Great Basin (T. e. vagrans). The other well-supported group was comprised of populations from the western Great Basin (T. e. vagrans). One population from the northern California coast (T. e. terrestris) was basal to both groups of populations. Thus, neither T. e. vagrans nor T. e. terrestris formed monophyletic groups. Average percent sequence divergence between the outgroup (T. sirtalis) and T. elegans was 7.9–12%. Within T. elegans, divergence among populations ranged from 0.3–7.7%.

Mitochondrial and nuclear gene variation is described from populations representing the range of two species of rare pygmy sunfishes, Elassoma boehlkei and Elassoma okatie, in the Carolinas. Mitochondrial control region sequences provide evidence for a minimum of four Evolutionarily Significant Units (ESU), two each within E. boehlkei and E. okatie. Significant allele frequency differences at a single nuclear gene locus corroborate the distinctiveness of these ESUs. Phylogenies based on control region haplotypes and frequencies of nuclear alleles are inconsistent with the currently described range of E. boehlkei and E. okatie. Despite inconsistency with described species boundaries, the result of this genetic analysis for rare species management is clear: conservation strategies that describe distinct population segments inhabiting individual river systems should be encouraged.

Juvenile snapping turtles may be highly susceptible to dehydration during overland movement because of their aquatic nature and large surface area to volume ratio. The present study examined the influence of body size and relative humidity on rates of evaporative water loss and estimates of survival time. Larger hatchlings had higher rates of evaporative water loss but longer survival times resulting from their greater absolute water contents. Rates of evaporative water loss decreased, and estimated survival times increased with increasing relative humidity. The findings suggest that evaporative water loss may be an important factor influencing survivorship and behavior during overland movements of juvenile snapping turtles.

A Memorandum of Understanding, which formed the Robust Redhorse Conservation Committee (RRCC), was developed and adopted by concerned stakeholders in Georgia, South Carolina, and North Carolina to attempt recovery of the recently “rediscovered,” and rare, robust redhorse Moxostoma robustum. As part of the conservation program, genetic analyses of robust redhorse populations were needed to facilitate responsible hatchery programs that could be used to supplement natural reproduction in declining populations and to reestablish populations in rivers in which it may have historically been present. We analyzed mtDNA control region sequences in robust redhorse from the Oconee and Ocmulgee Rivers in the Altamaha River drainage and the Savannah River to determine the genetic relatedness of these populations to guide restoration efforts. Fixed differences in mtDNA haplotypes were found between robust redhorse from the two drainages that strongly argues for the designation of these populations as Evolutionarily Significant Units and against the interstock transfer of fish. Further studies will be needed to evaluate the full significance of these differences and associated management implications.

The intramandibular septum of the lower jaw is commonly interpreted as a derived character supporting monophyly of anguimorph lizards. However, it is also present in snakes, consistent with the view that snakes are related to or nested within anguimorph lizards.

The currently available spliceosomal intron data were found to be of limited utility as phylogenetic characters for resolving the phylogeny of several clades of fishes. Phylogenetic relationships were inferred from a parsimony analysis of the distribution of introns among representatives of 18 major groups of vertebrates for seven genes. Phylogenetic signal of the spliceosomal intron data was limited to support for the monophyly of the Teleostei. The spliceosomal intron based phylogeny of B. Venkatesh, Y. Ning, and S. Brenner (in the Proceedings of the National Academy of Science, 1999) was evaluated and found to be fundamentally flawed. The analysis of B. Venkatesh, Y. Ning, and S. Brenner (in the Proceedings of the National Academy of Science, 1999) was compromised by errors in the treatment of missing and polymorphic data, the arbitrary exclusion of taxa, the assessment of homology, outgroups and rooting, the ordering and polarization of character states, and a failure to follow the logical implications of multiple equally parsimonious trees.

The aim of this study was to evaluate factors contributing to seasonal reproductive variation in a Neotropical frog, the Puerto Rican cave coquí (Eleutherodactylus cooki). There was a relatively small seasonal variation in ambient temperature and relative humidity in the caves occupied by E. cooki. Nonetheless, the reproduction of E. cooki was strongly seasonal, with clutches produced from March to November, and no additional clutches deposited from December to February. This seasonal reproductive pattern may reflect a response to small changes in the thermal environment, because the frequency of clutch production and number of clutches deposited per nest site increased when air temperature was warmest (during the middle of the breeding season). Clutches occurred singly (71% of all clutches) or in groups of two (23%), three (6%), or four (< 1%). The median clutch size was 15 (range = 1–29). Significant egg mortality occurred, despite male attendance of nest sites. The average rate of egg mortality was 16% per week. Extrapolating to a hatching period of 3.5 weeks, 44% of produced eggs survived to hatching. It appears that combined effects of weak environmental variation, clutch predation, and male parental care substantially influence the reproductive output of E. cooki.

A 579 base-pairs fragment of the cytochrome b gene has been sequenced for the four Heterobranchus species, four Clarias species, and Channallabes apus (Clariidae). Clarotes laticeps (Claroteidae) was used as outgroup. Results support the hypothesis that Heterobranchus is monophyletic. Clarias, however, appears to be paraphyletic.

The Baja California rattlesnake, Crotalus enyo, is a medium-sized rattlesnake restricted to the southern two-thirds of the Baja California peninsula. Very little is known about the natural history of this species. The goal of this study was to document the diet of C. enyo. I dissected the stomachs and hindguts of 113 preserved museum specimens of C. enyo and identified the ingested prey items. The diet of C. enyo consists of small rodents, lizards, and centipedes. Crotalus enyo of all sizes eat rodents and lizards, in contrast to many other rattlesnakes that eat almost exclusively lizards as juveniles and mammals as adults. However, C. enyo exhibits a modest ontogenetic shift in diet: small snakes eat lizards more often than do large snakes, and large snakes eat mammals more often than do small snakes. Adult C. enyo also eat large centipedes of the genus Scolopendra. Larger snakes tended to contain multiple prey items more often than smaller snakes, but this trend was not significant. Crotalus enyo is sexually dimorphic in size, with males being significantly larger than females. However, there is no significant gender difference in diet.

Examination of 122 specimens of the deep-sea fish, Bathypterois mediterraneus (Teleostei, Chlorophthalmidae), collected in the eastern Mediterranean and ranging from 35–158 mm SL, revealed that organization of the hermaphroditic gonad is first noticable in fish of 60–65 mm SL. At this stage, the two parts of the twin gonad are formed by elongated testicular and ovarial primordia enveloped in a common mesodermal tunic. Maturation of testes and development of eggs are described. The ovary is monocyclic, producing one spawn of approximatly 2400 eggs from the end of September to the beginning of November.

We resolve a minor confusion regarding the holotype of Caecilia volcani. The animal figured in the original description is not the one from which the measurements for the description were taken. The photographs are of a paratype at the Field Museum of Natural History (FMNH 189208). The holotype has had the wrong field number associated with it and is in the collection of the University of Kansas Natural History Museum (UKMNH 203035).

Hybognathus placitus collected from several west Texas streams exhibit sexual dimorphism in body form, which is unusual in cyprinids. Seventeen morphological measurements, including standard length, were made on 62 specimens and analyzed for sexual dimorphism. Partial warp scores were used to describe sexual dimorphism in body shape. There was no difference in standard length between males and females (ANOVA, P = 0.9038, F_1,60 = 0.0147), but there was a highly significant (MANOVA, F_1,60 = 4.78, P < 0.001) sexual dimorphism in body shape. Overall, males have relatively longer first dorsal fin rays, larger heads, and caudal peduncles, whereas females are deeper bodied and have relatively longer trunks, from the pelvic fin insertion to the anal vent. Differences between male and female H. placitus in length of the first dorsal fin ray are readily apparent and can potentially be used for field identification.

Brooding and nest-maintenance behaviors of the bagrid catfish Auchenoglanis occidentalis (Valenciennes, 1840) were studied in the southern end of Lake Tanganyika. We observed huge saucerlike nests, 1.2–3.8 m across, on the fine sand bottom of the littoral zone. The lowest parts of the nests were covered with an accumulation of coarse particles consisting mainly of gastropod and bivalve shells and shell-fragments, which the catfish sifted out from the sediment. Broods were buried within the shell accumulation and tended solely by males for up to two weeks until the juveniles were motile. Brooding males spent most of their time fanning the pectoral fins and undulating the posterior body. These movements resulted in water flow over the broods, which might serve to prevent oxygen deficiency. They did not act aggressively against intruding potential brood-predators. Nest distribution and relationships between nest size and shell content in the sediment suggest that nest site selection and nest size are determined by the shell availability in the sediment.