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The fixation of larval and juvenile fishes in 95% ethanol can be substituted for formalin and bears several advantages for morphological and molecular studies: 1) specimens clear and double stain rapidly and brilliantly; 2) otoliths are preserved; and 3) high-quality DNA is available from the tissues. We present merits and limitations of 70% ethanol and 95% ethanol as alternative fixatives to 4% buffered formalin. In particular, we compare our results of clearing and double staining teleost larvae and juveniles from these three fixatives and those that have been frozen at −20°C prior to the initial fixation. With our results, we can refute the long-standing notion that ethanol-fixed specimens disintegrate during clearing and staining.
We investigated food preferences of Atlantic Hagfish (Myxine glutinosa) in Bigelow Bight in the Gulf of Maine by deploying traps at three moderate depths (ranging from 61 m to 132 m) using different types of bait (fish, crabs, and clams) singly and in mixtures. We counted the numbers of specimens caught in each trap, recorded their individual weights and lengths, and noted the presence of eggs. Bait containing fish consistently attracted the greatest number of hagfish, while invertebrate-based baits were less effective: there was a nine-fold increase in catch rate for traps containing fish bait compared to traps containing only clam bait, and no hagfish were caught using only crab bait. Atlantic Hagfish appear to be adept at detecting even small quantities of fish because baits consisting of 10% fish and 100% fish were equally effective. Even at the relatively shallow and closely adjacent depths sampled we found longer and heavier hagfish at the deepest sampling sites, and individuals from those sites had larger eggs than those from shallower depths.
The haplochromine cichlid genus Labeotropheus is endemic to Lake Malaŵi, Africa. This genus presently contains two recognized species, Labeotropheus fuelleborni and L. trewavasae. As currently recognized, both species consist of geographically isolated populations scattered throughout the lake, each distinguished by a unique male nuptial color pattern. While other such allopatric populations of Lake Malaŵi cichlids have been described as different species, those of Labeotropheus have not, largely due to misunderstandings or misinterpretations of criteria applied to other Malaŵian endemics. Taking a refined approach to the recognition of putative species of Labeotropheus, I used morphometric, meristic, and color characteristics to describe two new, very similarly colored, species of Labeotropheus, both of which are found near Katale Island alongside the Luromo Peninsula in northwestern Lake Malaŵi.
In nature, prey are often simultaneously exposed to predators and competitors, leading to conflicting demands between survival and growth. Larval amphibians are model organisms to investigate the balancing of life history trade-offs because individuals must metamorphose before a wetland dries. Therefore, we deployed enclosures in a natural wetland to investigate the interactive effects of Wood Frog (Rana sylvatica) density (50 or 100 tadpoles) and Brook Stickleback (Culaea inconstans) presence on survival and growth of tadpoles. We hypothesized that the effects of conspecific density on tadpole survival and growth would be dependent on the presence of fish predators. Stickleback predation significantly decreased Wood Frog survival; however, a trend of higher tadpole survival with fish was detected at high conspecific densities. Wood Frog time to and mass at metamorphosis was not significantly affected by either conspecific density or stickleback presence. Our results demonstrate that Brook Sticklebacks can play a significant role in regulating Wood Frog survival in a Subarctic wetland, but the impact is likely dependent on tadpole density. Therefore, this research highlights the dynamic and complex effects of competition and predation in a Subarctic wetland. Our study also contributes to the limited understanding of factors affecting amphibian community structure in Subarctic wetlands.
Snailfishes of the genus Careproctus deposit egg masses inside the gill cavity of lithodid crabs. Previous attempts to identify the species depositing the eggs have been inconclusive because of the difficulties in identifying snailfish eggs and larvae. For this study, samples were collected from egg masses found in crabs in the commercial fishery and during benthic trawl survey work. Egg masses were found in Lithodes aequispinus (Golden King Crab) and, for the first time, in L. couesi (Scarlet King Crab). Mitochondrial DNA from the cytochrome c oxidase subunit I (COI) region was amplified from embryos and sequenced. Comparison of COI sequences from eggs to COI sequences from positively identified adult voucher specimens yielded identifications of 75 egg masses to species. A total of 38 egg masses were identified as Careproctus melanurus; 29 as C. colletti; seven as C. furcellus; and one as C. simus. Each egg mass contained eggs from only one species, and there was no indication of multiple maternal parentage. These results are the first positive identification of the snailfish species responsible for depositing egg masses in lithodid crabs. Identification of species involved may be useful in understanding the nature of this unique relationship between snailfishes and crabs.
A new species of Indo-Pacific grouper is described from nine specimens, 165–391 mm in SL. Epinephelus kupangensis, new species, is similar in appearance to, and has been treated as, Epinephelus amblycephalus (Bleeker, 1857). The two species are both found in deep waters of the Indo-Pacific and have overlapping ranges in eastern Indonesia, and likely beyond. Epinephelus kupangensis, new species, can be distinguished from Epinephelus amblycephalus on the basis of coloration, counts, and measurements. The species is characterized by the following set of characters: dorsal rays XI, 16; anal rays III, 8; pelvic rays I, 5; pectoral rays 18; caudal rays 18; caudal fin rounded; gill rakers 8 16; lateral line scales 48; longitudinal scale series 99; body scales ctenoid; scales on head cycloid and particularly large in size on opercle; orbit diameter 5.1 in head; pelvic fin 4.0 in head; maxillary streak orange; color when freshly dead pale grayish brown with five dark brown bars; orange-brown spots present dorsally on head and at edges and within dark bars.
The Western Pond Turtle (Actinemys marmorata), the only native freshwater turtle in California, occurs in a variety of habitats from sea level to about 2040 m elevation, from mesic forests to deserts. The San Joaquin Desert in California once supported large populations of this species in lakes, sloughs, and marshes fed by water from the mountains of the Sierra Nevada. Because of damming in the mountains and agriculture on the desert floor, much of the aquatic habitat is gone. Although some biologists proffered that only non-viable populations of Western Pond Turtles occurred in the San Joaquin Valley south of the delta, I found a surprisingly robust population of this species at Goose Lake, an ephemeral freshwater lake on the desert floor in northwestern Kern County. From 1995 to 2006, I marked 737 individuals. Growth rates and reproduction were fairly high compared to other populations of Western Pond Turtles in ponded waters. The average yearly population estimate was 597.4 turtles with annual survivorship estimates of 0.81 for adult males, 0.73 for adult females, 0.84 for juveniles 80–119 mm carapace length (CL), and 0.73 for juveniles <80 mm CL. The estimate of λ denoted a stable population. Although the population occurs in a habitat controlled by an agricultural water district, permanent water is always available and the site is secure from poaching. Despite severe decreases in numbers of turtles in the San Joaquin Desert over the past 100 y, based on this study and other recent studies, there are several populations of Western Pond Turtles in the area that appear to be large and stable.
Overland movement is an important aspect of freshwater turtle ecology. Turtles make overland excursions searching for mates, to find new aquatic habitats, in response to drought, or during nesting. Here, we tested how environmental factors may influence the excursion events of adult Red-eared Sliders (Trachemys scripta elegans). We found that 85% of turtles made overland movements at least once, which is higher than previously reported, and some turtles made multiple movements (2–6) during a single season. Rain and drought events were significant predictors of overland movements. While sex did not appear to be a significant factor, there was an indication that movement may depend on seasonal temperatures. In addition, we showed that turtles immigrated to depopulated ponds in a short period of time after a simulated harvest event. However, after a second harvest simulation, our experimental pond was not repopulated to its original abundance. Our results call for caution when implementing spatially controlled harvest regimes. Ponds depleted by harvesting might not be repopulated by immigrating turtles if source population sizes also decrease due to the regular dispersal to sink populations and subsequently slows overall reproduction rates.
In fishes, development is a plastic process, even among closely related, sympatric taxa. Selective pressure manifests itself through morphological divergences in early life. Of particular interest in the present study is heterochrony: alterations in developmental rates of change. Examinations of skeletal development in the Soft Sculpin, Psychrolutes sigalutes, and Tadpole Sculpin, Psychrolutes paradoxus, revealed marked developmental differences between species. While P. paradoxus quickly develops an adult skeleton and settles in adult habitat, P. sigalutes undergoes a remarkably protracted transformation (the transition from larval to juvenile characters) over a period of three to four months. It reaches sizes in excess of 40 mm (75% of adult size) before settling. While the earliest phases of life focus on the development of feeding elements and a transition from larval/anguilliform locomotion to caudal/subcarangiform propulsion, the two species diverge quickly in postflexion development. With the exception of feeding elements, the skeleton of P. sigalutes remains largely incomplete to sizes beyond 25 mm in length. By shunting resources typically dedicated to skeletal growth towards the development of mass alone, P. sigalutes quickly grows larger than any cohabitant zooplankton. Hiding by the day and hunting by night, P. sigalutes relies on its mass and inertia to chase down smaller prey hampered by the viscosity of water. The seasonality of P. sigalutes gives it ample time to grow before the majority of larval fishes hatch. Psychrolutes sigalutes may be a specialized ichthyoplankton predator, responsible for the earlier settlement times of cohabitant larvae.
Natural selection is predicted to favor the evolution of life history plasticity in response to differences in mortality risk between life stages, such that the duration of the more dangerous stage is reduced. I report a meta-analysis of 29 published tests of this hypothesis involving 20 amphibian species, in which exposure of embryos to predation risk was experimentally manipulated. The results confirm that amphibians are sensitive to risk during the embryonic stage, but the predictions of theory were only weakly upheld. Amphibians hatch at a less advanced developmental stage (0.24 SD units) and smaller body size (0.10 SD units) when exposed to predator species that consume eggs, but the expected decline in age at hatching (0.16 SD units) was not significant. Predators that consume larvae did not significantly delay hatching (0.19 SD units) or influence any other response.
Bufo intermediusGünther, 1858, has a complex taxonomic history, with the type series being reported from Guayaquil and the Andes of Ecuador. However, these specimens are not referable to any known South American bufonid species. We examined the type series and found, based on morphology, that the specimens likely represent a Mesoamerican species, as earlier authors had suggested. We further explored this possibility by analyzing the stomach contents of one of the syntypes. The unique combination of arthropods, particularly the presence of the beetle species Megalostomis dimidiata and Zygogramma signatipennis, confirmed that the Ecuadorian locality data are erroneous and that the type series was collected in Mexico. We here present that the types of Bufo intermedius are conspecific with the Mexican species Incilius occidentalis (Camerano, 1879) and propose a new synonymy between Bufo intermediusGünther, 1858 and Incilius occidentalis (Camerano, 1879). An application has been made to the International Commission on Zoological Nomenclature to preserve prevailing usage of the junior name Incilius occidentalis for this widespread Mexican species.
Morphology-based studies of squamate phylogenetics recover very different topologies from studies that use molecular or combined molecular and morphological data. This has led to some stimulating dialogue regarding the respective merits of the alternative hypotheses, with the primary point of disagreement being the placement of Iguania. Molecular phylogenetic studies place Iguania in a highly nested position as a member of the clade Toxicofera, additionally containing Anguimorpha and Serpentes, whereas morphology-only studies have traditionally placed Iguania as sister to all remaining squamates. McMahan and colleagues recently posited that the molecular phylogenetic hypothesis of the placement of Iguania is a result of incorrect root placement. These authors mapped molecular data (i.e., DNA sequence data) onto phylogenetic hypotheses and identified more molecular apomorphies on the basal branches of the morphology-based phylogeny. They concluded from this result that the molecular data support the morphological phylogenetic hypothesis of Iguania being sister to all remaining squamates. Here, we map molecular data onto additional phylogenetic hypotheses and show that the conclusions of McMahan and colleagues are flawed for three key reasons: 1) they misinterpreted a measure of branch length as a measure of branch support; 2) they considered only two phylogenetic hypotheses; and 3) their counts of molecular apomorphies are severely biased by their decision to collapse clades into large polytomies. We demonstrate that counting the molecular apomorphies along a given branch is a poor measure of support for a clade and that the molecular data do not provide support for the morphology-based squamate phylogeny as the optimal topology.
Clearing and staining techniques are widely used to study the structure of small vertebrates. These techniques consist mainly of soft tissue clearance by enzymatic or caustic digestion and staining of bone, cartilage, or nerves. However, although there is an increasing need to describe other soft-anatomy structures, such as ligaments and tendons, the methods available to visualize these tissues are a challenge that requires very fine dissections and three-dimensional reconstructions using tissue sections or microtomography. In this paper we present a simple and economical method for staining fibrous connective tissues, particularly ligaments and tendons. The method begins with an enzymatic proteolysis that prevents unselective soft tissue degradation. Then the bones are stained to facilitate understanding the structure associated with the bone tissue of interest. Subsequently, the connective tissues are stained in two steps, first with a deep stain and then with an alcoholic differentiation. The final products are stored in glycerol. Our technique has the advantages of being as simple and short as traditional staining techniques of bone and cartilage, requires inexpensive materials and equipment, and is applicable to specimens preserved in museums. We demonstrate that our high-performance method works well with specimens of the major vertebrate groups. This approach will facilitate anatomical description of the musculoskeletal system, helping morphological, functional, and taxonomic analyses.
The cat-eyed snakes of the genus Madagascarophis are among the most commonly encountered snake species in Madagascar. Yet despite their broad distribution and frequent occurrence in human-disturbed habitat, Madagascarophis still contains unrecognized species diversity. Here, we describe a new species of Malagasy cat-eyed snake from a specimen found in the tsingy karst system of Ankarana in northern Madagascar. Using multiple loci from all currently described species, including the never-before-sequenced M. ocellatus, we delimit a new species and also determine its placement within the genus in a Bayesian coalescent framework, using BPP and *BEAST, respectively. Our results indicate that molecular data are sufficient to delimit this new taxon. These data also support its placement as the sister taxon to the recently described M. fuchsi which is endemic to the Montagne des Français karst massif also in northern Madagascar. We also provide a morphological description of this new snake species, which can be readily diagnosed based on external morphological characters, and include a species identification key for the entire genus based on external morphology.
Estimating the cost of reproduction is pivotal to understanding the trade-off between current and future reproductive success, a key prediction in life-history theory. Increases in the cost of each reproductive attempt theoretically reduce future reproductive ability. Further, costs may change as individuals grow thus changing the nature of this trade-off. Measuring changes in female locomotor ability during reproduction has been one effective method to measure the cost of reproduction for females. We measured female Diamond-backed Watersnake (Nerodia rhombifer) swimming speed during and after pregnancy to determine if there was a loss of locomotor ability. We then correlated these speeds with measures of reproductive burdening (as estimated by relative clutch mass) and body size to investigate if increased reproductive investment and body size changed locomotor ability and subsequent cost of reproduction. Female snakes swam slower during pregnancy than after. Larger relative clutch masses resulted in slower swimming speeds during pregnancy. Further, shorter individuals showed a greater decrease in swimming speed suggesting a greater cost of reproduction for smaller individuals. Lastly, we demonstrated that additional costs to locomotor ability may be incurred by the female due to weight loss during pregnancy from carrying the burden of reproductive material.
The coexistence between sharksuckers and sharks is poorly understood. Here, we studied the symbiotic client-cleaner relationship between Lemon Sharks, Negaprion brevirostris, and sharksuckers, Echeneis naucrates, with a focus on cleaning inside the sharks' mouths. Where observable, cleaning bouts were either initiated by a sharksucker moving along a shark's snout while maintaining body contact or by swimming in a “dance like” manner in front of the shark's eye without contact, until the shark gaped to allow entry. Sharksuckers interacting with sharks were typically in their first year of their life. While being cleaned by sharksuckers, Lemon Sharks were always seen in one of two positions: either lying flat on the sea floor, or propped on their pectoral fins. Cleaning bouts lasted significantly longer when the shark was propped. In bouts where the location of sharksucker activity within the mouth could be determined, cleaning activity exclusively occurred around the teeth of the upper jaws. In more than half of the bouts, the shark terminated the cleaning by spitting out the sharksucker. Overall, Lemon Sharks and sharksuckers show a highly evolved client-cleaner relationship with both able to influence and trigger the other's behavior.
The number of species of the congrid eel genus Conger in Japan has been unsettled for more than half a century. The principal authors have disagreed over how many species are present and what their correct names are. The main question involves the identity of Conger japonicusBleeker, 1879. It has variously been treated as a valid species or a synonym of Conger myriaster (Brevoort, 1856). We examined the holotype and determined that Conger japonicus is a synonym of Conger myriaster. The four valid species of Conger in Japan are Conger cinereus, Conger myriaster, Conger erebennus, and Conger jordani.
The growth and reproductive characteristics of Longnose Gar, Lepisosteus osseus, from the tidal portions of the major rivers in Virginia were analyzed using a three-dimensional population demographic model. This was the first study concerning Longnose Gar to test multiple growth models, and the biphasic double von Bertalanffy model best fit the data for both males and females. Male Longnose Gar grew to their asymptotic length significantly faster than female Longnose Gar, but after maturity the growth coefficients were not significantly different. Longnose Gar had high fecundity and spawning occurred amongst a bed of Hydrilla verticullata between May and June. Longnose Gar share a trait (large eggs) with equilibrium strategists but overall are closer to the periodic strategist side of the demographic continuum by displaying large adult size, delayed maturation, and high fecundity.
Fever is an evolutionarily conserved and effective organismal response used to reduce infection burden. Although ectotherms are unable to induce a fever endogenously because they only produce negligible heat from their metabolism, they can increase their body temperature in response to infection by selecting warm microclimates (“behavioral fever”). For amphibians, behavioral fever is hypothesized to be critical in their defense against pathogens because many amphibian immune parameters are more effective at warm temperatures. We explored this topic using the pathogenic amphibian chytrid fungus (Batrachochytrium dendrobatidis; “Bd”), a fungal pathogen implicated in the worldwide amphibian declines. Behavioral fever in amphibians should be an effective defense against Bd because fungal growth is temperature dependent and does not survive above 30°C. We conducted a laboratory experiment in which we allowed Bd-infected and sham inoculated metamorphic American toads (Anaxyrus americanus) to behaviorally thermoregulate. During the experiment, we recorded the body temperature of each toad and also determined their Bd infection intensity. Bd-infected toads behaviorally increased their body temperatures through the course of an infection compared to sham inoculated toads, which did not change their body temperatures. In addition, toads with higher initial Bd infection intensities (measured prior to the start of the thermoregulation experiment) had higher average body temperatures compared to the body temperature of toads with lower infection intensities. Collectively, these findings build upon our understanding of the relationship between temperature and disease in the amphibian-Bd system and offer hope that amphibians might be able to induce behavioral fevers to clear their Bd infections in nature.
Of the many environmental factors that could affect swimming performance and critical swimming speed (Ucrit), turbidity has received relatively little attention. The purpose of this study was to examine the effects of turbidity on Golden Shiner (Notemigonus crysoleucas) swimming performance through the analysis of critical swimming speed. It was found that turbidity had an effect on critical swimming speeds; critical swimming speeds increased significantly with rising turbidity values. At the highest turbidity levels reported in this paper, Golden Shiner experienced a 56.5% increase in critical swimming speed over controls swimming in clear water. We likewise observed an increase in swimming efficiency and cost of transport with increasing turbidity. We suggest that a hydrodynamic effect may be the most likely explanation for the increase in performance and swimming efficiency observed in this study.
Crocodilians exhibit powerful antibacterial activities in their tissues and blood. The activities have been partially attributed to the presence of a potent serum complement system of proteins that acts in a nonspecific manner to kill bacteria. Complement activation involves activation of complement C3, a component with broad immune and regulatory function. We searched the crocodilian genomes (Alligator mississippiensis, Crocodylus porosus, and Gavialis gangeticus) for complement C3, and found two genes that code for isoforms with quite different sequences. Birds and mammals express only a single isoform of the complement C3 protein. Some snakes were shown to have two C3 genes; however, these encode proteins with very similar amino acid sequences. To date, only fishes were reported to express complement C3 isoforms with diversity similar to that of the crocodilian forms. Phylogenetic analysis suggests the gene duplication leading to the two crocodilian paralogs probably occurred within the order Crocodylia. Both contain signal sequences, putative internal thioesters, potential N-glycosylation sites, and functional domains that would allow them to interact with complement receptors and other complement system components. As has been suggested with fishes, the expression of multiple functional C3 isoforms may allow crocodilians to respond to a broad spectrum of immunological insult.
The Amblyopsidae is a small family of fishes from North America in which most of the species occur in caves. Despite considerable interest and study by biologists, a comprehensive morphological phylogenetic analysis of the family has not been conducted to date. We examined the skeletal morphology of all six genera and recognized species, which included 66 characters. The resulting phylogeny was compared to morphological- and molecular-based phylogenies of previous studies. Results showed a progression of cave adaptation that was significantly different from previous phylogenetic studies. Amblyopsidae was supported by 34 synapomorphies of the skeleton, but relationships within the Amblyopsidae were comparatively weak. The relationships of amblyopsids are likely influenced by morphological convergence as well as changes in the timing of development of some characters. Heterochrony is most visible in the unfused bones of the dorsal portion of the skull. The sister group to Amblyopsidae is Aphredoderidae (pirate perches), and the main character that supports this relationship is the presence of a unique set of upper jaw bones termed here lateromaxillae. This relationship is also supported by an anterior position of the vent, which is used for expelling gametes in Aphredoderus and for moving eggs to the gill chamber in Amblyopsis. It is more likely that Amblyopsis is the only branchial brooding amblyopsid and all other species likely exhibit transbranchioral spawning.
The Committee on Graduate Student Participation was formed in 1984 with the mission to “deal with the matter of how graduate students can become more involved in Society affairs”. Well before this time, however, graduate students were an active part of the American Society of Ichthyologists and Herpetologists membership. With mentorship and encouragement from senior members, graduate students have received career-building grants, served on multiple committees, and worked to engage in the Society in novel and meaningful ways. Herein, we review reflections of past award winners, initiatives stemming from graduate students themselves, and a summary of the attendance and fundraising that graduate students have brought to the Society.
The academic world is full of people with rich personalities, brilliant minds, and eclectic interests. Thomas (T. H.) Frazzetta certainly was a special one of these. He passed away on New Year's Eve 2015, following several months of ill health. Ironically, New Year's Eve was one of his favorite holidays, only exceeded by Halloween. Sadly, he was unable to celebrate either in his final year.
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