We investigated sound production and the sonic motor system in the Pineconefish, Monocentris japonica. The hand-held Pineconefish produced one type of sound (main frequencies: 100–600 Hz) in both water and air. The sonic organ consists of the swimbladder and a pair of extrinsic sonic muscles originating from exoccipital of the cranium and supracleithrum and inserting on the anterodorsal surface of the swimbladder and partly on vertebrae. The sonic muscle is innervated by occipital nerve branches, not the spinal nerves. Injections of wheat germ agglutinin-conjugated horseradish peroxidase into the sonic muscle resulted in labeled sonic motor neurons ipsilateral to the injections. The labeled neurons were located in the ventral zone of the caudal medulla oblongata, forming a column of sonic motor neurons (or the sonic motor nucleus) from the level of the vagal nerve root to the rostral part of the third ventral root of the occipital nerve. The total number of motor nerve fibers contained in the right and left sonic nerve branches (standard length  =  96 mm) were 363 and 369, respectively. We conclude that the sonic muscles of Monocentris japonica are innervated by approximately 700 sonic motor neurons located only in the caudal medulla oblongata.

Eurycea sosorum and E. nana are plethodontid salamanders endemic to several karst springs in central Texas. Landscapes around these habitats are increasingly urbanized. At the Barton Springs complex, where E. sosorum occurs, average dissolved oxygen (DO) in the main flow is approximately 6.5 mg L⁻¹. However, DO is quite variable, ranging between 2.4 and 10 mg O₂ L⁻¹, and recent data suggest a positive relationship between DO and spring discharge in Barton Springs Pool, though this relationship may not be as strong under extreme low-flow conditions. Here we examine sensitivity of a surrogate species, E. nana, to experimental variation in oxygen availability (DO); due to limited availability of E. sosorum, they were examined in only a subset of experiments. A suite of traits was measured on adults: spontaneous activity, metabolic rate, and mortality during 28 days of exposure. A separate experiment examined growth of juveniles across levels of DO during 60 days of exposure. Levels of DO below 3.4 mg O₂ L⁻¹ appeared to pose a grave threat to salamander survival over a 28-day study, whereas DO above 4.5 mg O₂ L⁻¹ gave no observable effects in any experiment. Between these values is a critical range in which salamanders became progressively compromised. An ambient water quality criterion for DO in lentic systems (5 mg O₂ L⁻¹, 24 hour minimum) appears adequate to protect Eurycea.

In this study, we use restriction fragment length polymorphisms (RFLP) of the mtDNA ND2 gene to identify to species cyprinid eggs collected from a spawning aggregation substrate in the Pascagoula River system. A library was generated with inter- and intra-specific RFLP patterns for nine cyprinids: Notropis baileyi, N. texanus, N. longirostris, N. amplamala, Nocomis leptocephalus, Luxilus chrysocephalus, Lythrurus roseipinnis, and Cyprinella venusta. Eggs of three species were identified from a single nest, while only one species was observed spawning at the site. These results confirm that RFLP is an effective method for identifying unknown eggs of nest associates, and North American cyprinids in general.

Pesticides commonly occur in ecological communities at relatively low concentrations, leading to growing interest in determining the sublethal effects of pesticides. Such effects should affect individuals and, in turn, alter interspecific interactions. We sought to determine how sublethal concentrations (0.1 and 1.0 mg/L) of two common pesticides (carbaryl and malathion) affected predator and prey behavior as well as subsequent predation rates. We conducted a series of experiments using three species of larval amphibians (Gray Treefrogs, Hyla versicolor; Green Frogs, Rana clamitans; and American Bullfrogs, R. catesbeiana) and three species of their predators (larval dragonflies, Anax junius; adult water bugs, Belostoma flumineum; and adult Red-spotted Newts, Notophthalmus viridescens). We found that the pesticides frequently reduced the activity of all three tadpole species. For the two invertebrate predators (Anax and Belostoma), the pesticides were lethal, precluding us from examining sublethal effects on predator–prey interactions. However, newt survival was high and the addition of the pesticides reduced the predation rates of newts in one of the three tadpole species. There were no effects of the pesticides on the striking frequency of the newts or on their prey capture efficiency. Thus, the mechanism underlying the pesticide-induced reduction in predation rates remains unclear. What is clear is that sublethal concentrations of pesticides have the potential to alter prey behavior and species interactions and thereby alter the composition of ecological communities.

Sandveld lizards (genus Nucras) are widespread in southern Africa, but are generally secretive and poorly known. We examined 385 preserved specimens from five species of Nucras collected over a broad time span (104 years) and a geographic area covering most of South Africa and Swaziland. We had three main objectives: to test for sexual size dimorphism, to quantify male and female reproductive cycles, and to determine diet. In addition, we examined the importance of scorpions in the diet of Nucras based on previous studies reporting an unusually high incidence of scorpions in the diet of Kalahari N. tessellata. Males of all species except N. lalandii had significantly larger heads than females of the same body size, although females had significantly greater snout–vent length than males in three of the five species examined. The general reproductive pattern was for females to contain vitellogenic eggs during late spring and early summer. No females simultaneously contained oviductal and vitellogenic eggs, which suggests that females produce only one clutch per season. Clutch size was unrelated to female body size in all species examined. Female follicle volume generally coincided with male testicular volume, indicating for the most part synchronized reproductive cycles between the sexes. Testis volume was generally highest during spring–early summer, with only N. holubi showing a second peak in autumn. We recorded 15 arthropod orders in the diet of Nucras. All species feed on invertebrates, primarily insects, and, to a lesser degree, spiders and centipedes. Termites, grasshoppers, and beetles both numerically and volumetrically dominated their diet. We found no evidence that scorpions form a major part of the diet of any of these five species of Nucras, including N. tessellata from biomes outside the Kalahari Desert.

The examination of museum specimens allows for the robust analysis of ecological and life history traits in snakes, and can be especially useful in revealing characteristics often undetected in geographically limited studies. We measured and dissected 242 Psammophis crucifer and 358 Psammophylax r. rhombeatus, two widespread and abundant psammophiids from southern Africa, and quantified sexual size dimorphism (SSD), feeding habits, and geographic variation of these traits throughout their range. Female P. crucifer and male P. r. rhombeatus were larger than the opposite sex, both species were saurophagous but P. r. rhombeatus incorporated a wider range of taxa, and the reproductive biologies of both species were consistent with those of their congeners. We also examined intraspecific variation in these ecological traits based on differences in annual and seasonal rainfall patterns across their broad distribution. In large part the ecology of these temperate-inhabiting snakes mirrors that of other psammophiids and convergent whipsnakes.

Resource managers often have little information regarding the habitat requirements and distribution of rare species. Factor analysis-based habitat suitability models describe the ecological niche of a species and identify locations where these conditions occur on the landscape using existing occurrence data. We used factor analyses to assess the suitability of habitats for Thamnophis gigas (Giant Gartersnake), a rare, threatened species endemic to the Central Valley of California, USA, and to map the locations of habitat suitable for T. gigas in the Sacramento Valley. Factor analyses indicated that the niche of T. gigas is composed of sites near rice agriculture with low stream densities. Sites with high canal densities and near wetlands also appeared suitable, but results for these variables were sensitive to potential sampling bias. In the Sacramento Valley, suitable habitats occur primarily in the central portion of the valley floor. Based upon the results of the factor analyses, recovery planning for T. gigas will require an on-the-ground assessment of the current distribution and abundance of T. gigas, maintaining the few remaining natural wetlands and the practice of rice agriculture in the Sacramento Valley, and studying the effects of agricultural practices and land use changes on populations of T. gigas.

We measured 17 morphometric characters of 38 females and 50 males from one of the largest known populations of the Himalayan Newt, T. verrucosus, located in the Darjeeling District of West Bengal, India. To evaluate the proximate causes of sexual dimorphism, we determined individual age by skeletochronology. At the breeding site, females were significantly longer and heavier than males and had larger heads and longer limbs. Despite their smaller size, males had bigger cloacae and higher tails. Females were, on average, 2.5 years older than males, and about 26% of them were older than the oldest male sampled. In both sexes, snout–vent length increases with age. Males were smaller than females independent of age: the difference in the mean age at maturity (2.5 for males and 3.2 for females) is the main source of the observed sexual size dimorphism. With the effects of body size statistically removed, males show proportionally longer forelimbs, longer tails, and a different head shape. The results are discussed in the light of life history and differences in mating behavior between the sexes.

Age, longevity, size, and the effects of climate on growth and age at sexual maturity were analyzed in four populations of Pleurodema thaul (Leiuperidae) from Chile by comparing two populations at different latitudes but similar altitude (Limarí and Chaitén), and two populations at similar latitude but different altitudes (Itata and Laja). Body size was measured and age was estimated by skeletochronology applied to phalanges. In each population there was a positive relationship between body size and age, and growth decreased gradually after maturity. The longevity was estimated to be five years for females and males; age structures were similar between sexes. Pleurodema thaul showed intra-population variation in the degree of sexual dimorphism in growth patterns, age at sexual maturity, and size. Females were larger than males in the low altitude and latitude populations (Limarí and Itata), but did not differ significantly at high altitude and latitude populations (Chaitén and Laja). In all populations, sexual maturity was reached at two years of age by both sexes except that some females at high altitude and latitude did not mature until three years of age. The growth coefficient, according to von Bertalanffy's model, was greater in females than in males from Chaitén, greater in males from Limarí, and was similar between sexes in Itata and Laja. Pleurodema thaul populations from high latitude and altitude showed slower growth than populations from low latitude and altitude, but individuals achieved larger body size. The mean annual growth rate was greater in populations located at high altitude or latitude for males and females. These results allow inference of the responses of amphibians to changes in the environment, which is key for generating conservation strategies.

The structures within the gill pore of lampreys are shown to be a new taxonomic character. Papillae along the posterior margin of the gill pore cup, termed marginal papillae, vary in number, size, shape, and arrangement among species. The size and shape of a central process that extends posteriorly from the mid-lateral area of the wall of the gill pore cup is also of taxonomic significance. Examples are provided to show that there is stability of the character within an individual and among populations of a particular species. However, an example of the variation in counts over the range of Lampetra ayresii indicates that it is the average number of papillae, their arrangement, shape, and associated size in addition to the shape and size of the central process that may be of taxonomic significance. Examples of the usefulness of the new characters are provided for L. pacifica and Entosphenus folletti. The numbers and size of the marginal papillae readily distinguish L. pacifica from L. richardsoni. The number of marginal papillae and shape of the central process indicate that the holotype and paratypes of E. folletti may not be the same species. The full taxonomic value of these structures remains to be determined, but these initial studies indicate that the structures within the gill pore cup provide a method of improving the interpretation of speciation in lampreys, particularly for nonparasitic species.

Field activities in several localities within the basin of the Doce River, state of Minas Gerais, Brazil, resulted in the collection of a new Ischnocnema that we assign to the I. verrucosa species series. The new species resembles I. verrucosa and I. octavioi by its possession of small digital discs, short legs, conspicuously tuberculate dorsal surfaces, a W-shaped mark between the shoulders with two large tubercles at the bases, and a red iris with a vertical black bar in life. It differs from I. verrucosa and I. octavioi by its possession of externally indistinct tympanum and tympanic annulus and visible white glandular-appearing nuptial pads in males. We also assign I. octavioi and I. penaxavantinho to the I. verrucosa species series.

A new species of Otocinclus (Loricariidae) is described from tributaries to the Rio Madeira, in the State of Amazonas, Brazil. The new taxon can be distinguished from its congeners by lacking middle abdominal plates between the lateral abdominal plates, and by having the dark spot at the base of the caudal fin separated from the midlateral stripe by an unpigmented or slightly pigmented area, and not extended posteriorly onto the middle caudal-fin rays.

A new species of the liparid genus Paraliparis is described from the eastern Bering Sea. Paraliparis penicillus, new species, described from six specimens, differs from its North Pacific congeners in having the following combination of characters: deep, rounded head; simple teeth; high tooth-row count; triangular opercular flap directed posterodorsally; gill slit located entirely above pectoral fin or reaching to rays 3–4; low lower pectoral-fin-lobe ray count; black peritoneum; pale stomach; absence of prickles on skin. Specimens were collected from depths of 722–1003 m during bottom trawling operations.

Four new cyprinid species of the Rasbora trifasciata-group, Rasbora api, R. nodulosa, R. kluetensis, and R. truncata, are described from northwestern Sumatra, Indonesia. Rasbora api is distinguished from its congeners in the R. trifasciata-group by an anteriorly tapering black midlateral stripe extending posteriorly along the flank from the first lateral-line scale system and terminating at a slightly wider black basicaudal spot on the caudal-fin base, and stout conical cephalic tubercles with basal portion bearing microgranules (Type A tubercles). Rasbora nodulosa is distinguished from its congeners in the species group by having nodular and smaller cephalic tubercles (Type D tubercles). Rasbora kluetensis is distinguished from its congeners in the species group by the conical cephalic tubercles with a somewhat protruded base bearing microridges (Type E tubercles). Rasbora truncata differs from its congeners in the species group by a combination of meristic, pigmentary, and tuberculation features, and details of the lateral line system. Other members of the R. trifasciata-group in the region, Rasbora meinkeni and R. tobana, are redescribed. Rasbora tobana is resurrected. Three new areas of endemism in northwestern Sumatra are proposed based on the distributions of three new endemic species: the Tripa District represented by R. nodulosa, the Kluet District represented by R. kluetensis, and the Alas District represented by R. truncata.

Smallmouth Bass (Micropterus dolomieu) and Largemouth Bass (M. salmoides) are congeneric species that co-occur in many lentic and lotic systems, but have never been documented to hybridize in the wild. In 2003, a long-term study of reproductive ecology of M. dolomieu encountered a nest defended by a male M. dolomieu with two distinctly different size sets of eggs. The size range of one set of eggs was consistent with that observed for M. dolomieu, but the size range of the second set of eggs was too small for M. dolomieu and was within the size range for M. salmoides. A sample of fin tissue from the male guarding the brood and a subsample of both size classes of offspring were collected. Molecular genetic techniques (protein electrophoresis, microsatellite analysis, and RFLP analysis of mtDNA) confirmed that progeny from the larger eggs were from a mating between the nest-guarding male and a female M. dolomieu and that those from the smaller eggs were from a mating between the nest-guarding male and a female M. salmoides. The most plausible explanation for the breakdown of prezygotic isolating mechanisms is that the very low abundance of adult M. salmoides precluded conspecific mating for the female M. salmoides.

The Panaque nigrolineatus group (subgenus Panaque) is revised; three nominal species—P. cochliodon, P. nigrolineatus, and P. suttonorum—are redescribed and three new species are described. Panaque armbrusteri, new species, is widespread in the Tapajós River and its tributaries in Brazil and is distinguished by having a supraoccipital hump, higher numbers of jaw teeth and an ontogenetic increase in interpremaxillary and intermandibular tooth-row angles, relatively short paired-fin spines, and dorsal margin of infraorbital six flared laterally. Panaque schaeferi, new species, is widespread in main-channel habitats of the upper Amazon (Solimões) River basin in Brazil and Peru; it is distinguished by having a coloration consisting of dark or faded black spots evenly distributed on a pale gray to brown base, and by its large adult body size (>570 mm SL). Panaque titan, new species, is distributed in larger, lowland to piedmont rivers of the Napo River basin in Ecuador, and is distinguished by having a postorbital pterotic region bulged beyond the ventral pterotic margin, coloration consisting of irregular and widely spaced dark gray to brown stripes on light brown to tan base, and large adult body size (>390 mm SL). A relatively large pterotic, indicative of an enlarged gas bladder and gas bladder capsule, and allometric increases in tooth number are hypothesized to be synapomorphies uniting members of the subgenus Panaque.

The Doumea chappuisi complex within the catfish family Amphiliidae is diagnosed on the form of the dorsolateral and ventrolateral processes of the vertebrae along the posterior portion of the body. Three species are recognized in the complex: Doumea chappuisi of the West African coastal river basins in Guinea, Guinea-Bissau, Cote d'Ivoire, and Liberia; D. reidi, new species, described herein from a portion of the upper Sanaga River in Nigeria; and D. stilicauda, new species, described herein from the Nyong River basin in Cameroon. Members of the complex are distinguished from each other on the basis of the overall body form, the caudal-peduncle length, the predorsal length, the head length, the degree of development of the pelvic fin in larger specimens, the anterior extent of the exposed vertebral processes along the ventral surface of the body, and details of the pigmentation pattern of the unbranched rays of the pectoral and pelvic fins.

The Stippled Darter, Etheostoma punctulatum, has long been recognized as a single species of the subgenus Ozarka, endemic to the clear, high-gradient creeks and rivers of the Arkansas, White, and Missouri river drainages in the Ozark Plateau of the Interior Highlands of North America. Etheostoma punctulatum is redescribed and two new species are described based on morphological and allozyme characters, and phylogenetic analyses. The Stippled Darter, E. punctulatum, is restricted to tributaries of the Missouri River. The Autumn Darter, E. autumnale, new species, is endemic to the White River system, Missouri and Arkansas. The Sunburst Darter, E. mihileze, new species, is known only from the Arkansas River system, Missouri, Arkansas, Oklahoma, and Kansas. The three species are found to be divergent and diagnosable from one another and represent valid species under a variety of species concepts. Phylogenetic analyses indicate that E. punctulatum is sister to E. mihileze, new species, plus E. autumnale, new species.