Heterochrony and the evolution of the longjaw mudsucker (Gobiidae, Teleostei).

Although longjaw mudsucker (Gillichthys mirabilis, Gobiidae) has been studied extensively for its ability to occupy low-oxygen environments, few studies have addressed the evolution of its exceptionally elongated jaws that extend posteriorly beyond the gill opening in large adults. In this study, the ontogeny of the maxillae of G. mirabilis, Gillichthys seta, and the out-group species Eucyclogobius newberryi was studied within the heterochrony framework using digitized landmarks and caliper measurements. The results show that the maxilla of both species of Gillichthys evolved via acceleration (increased growth rate) and that of G. mirabilis via hypermorphosis (continued growth to a larger body size); two forms of peramorphosis. This is in contrast to earlier studies that concluded that G. seta is paedomorphic. We were unable to confirm an earlier hypothesis of sexual dimorphism in the jaw length of G. mirabilis. The evolution of the elongated jaws and associated large buccopharyngeal membrane in G. mirabilis is hypothesized to increase the surface area for gas exchange during aerial respiration and may also serve to amplify the aggressive gaping display as observed in other fishes.

Laboratory-based measures of temperature preference and metabolic thermal sensitivity provide insight into the habitat utilisation of juvenile California horn shark (Heterodontus francisci) and leopard shark (Triakis semifasciata).

Laboratory-based studies examining fish physiological and behavioural responses to temperature can provide important insight into species-specific habitat preferences and utilisation, and are especially useful in examining vulnerable life stages that are difficult to study in the wild. This study couples shuttle box behavioural experiments with respirometry trials to determine the temperature preferences and metabolic thermal sensitivity of juvenile California horn shark (Heterodontus francisci) and leopard shark (Triakis semifasciata). As juveniles, these two species often occupy similar estuarine habitats but display contrasting behaviours and activity levels - H. francisci are relatively sedentary, whereas T. semifasciata are more active and mobile. This study shows that juvenile H. francisci and T. semifasciata have comparable thermal preferences and occupy similar temperature ranges, but H. francisci metabolism is more sensitive to acute changes in temperature as expressed through a higher Q10 (H. francisci = 2.58; T. semifasciata = 1.97; temperature range: 12-24°C). Underlying chronic temperature acclimation to both warm (21°C) and cool (15°C) representative seasonal temperatures did not appear to significantly affect these parameters. These results are discussed in the context of field studies examining known distributions, habitat and movement patterns of H. francisci and T. semifasciata to better understand the role of temperature in species-specific behaviour. Juvenile H. francisci likely target thermally stable environments, such as estuaries that are close to their preferred temperature, whereas juvenile T. semifasciata metabolism and behaviour appear less dependent on temperature.

US county-level estimation for maternal and infant health-related behavior indicators using pregnancy risk assessment monitoring system data, 2016-2018.

BACKGROUND: There is a critical need for maternal and child health data at the local level (for example, county), yet most counties lack sustainable resources or capabilities to collect local-level data. In such case, model-based small area estimation (SAE) could be a feasible approach. SAE for maternal or infant health-related behaviors at small areas has never been conducted or evaluated. METHODS: We applied multilevel regression with post-stratification approach to produce county-level estimates using Pregnancy Risk Assessment Monitoring System (PRAMS) data, 2016-2018 (n = 65,803 from 23 states) for 2 key outcomes, breastfeeding at 8 weeks and infant non-supine sleeping position. RESULTS: Among the 1,471 counties, the median model estimate of breastfeeding at 8 weeks was 59.8% (ranged from 34.9 to 87.4%), and the median of infant non-supine sleeping position was 16.6% (ranged from 10.3 to 39.0%). Strong correlations were found between model estimates and direct estimates for both indicators at the state level. Model estimates for both indicators were close to direct estimates in magnitude for Philadelphia County, Pennsylvania. CONCLUSION: Our findings support this approach being potentially applied to other maternal and infant health and behavioral indicators in PRAMS to facilitate public health decision-making at the local level.

The Pandemic Blenny, Coralliozetus clausus, a new species of tube blenny endemic to Isla del Coco, Costa Rica (Teleostei: Chaenopsidae).

Coralliozetus clausus, a new species of chaenopsid blenny, endemic to Isla del Coco, Costa Rica, is described. This small species, not exceeding 15 mm SL, is a short-bodied member of the genus along with Coralliozetus cardonae (Caribbean), Coralliozetus angelicus, and Coralliozetus springeri (both eastern Pacific). It differs from its closest relative, C. springeri, known from mainland waters from Costa Rica to Ecuador, in having a single tiny supraorbital cirrus and dark dots on the operculum and branchiostegal membrane of males while C. springeri has paired supraorbital cirri (one of which is substantial in size) and no dots on the operculum. Although two other species of Coralliozetus have been reported from Isla del Coco, this appears to be only member of the genus present on the island. It is the second chaenopsid endemic to Isla del Coco and brings the number of cryptobenthic fishes endemic to Isla del Coco to twelve.

Acanthemblemaria aceroi, a new species of tube blenny from the Caribbean coast of South America with notes on Acanthemblemaria johnsoni (Teleostei: Chaenopsidae).

Acanthemblemaria aceroi new species is described from the upwelling region of the Caribbean coasts of Venezuela and Colombia. It differs from its closest relative, Acanthemblemaria rivasi Stephens, 1970, known from Panama and Costa Rica, in the posterior extent of the infraorbitals, details of head spination, and unique COI sequences. The description of Acanthemblemaria johnsonsi Almany Baldwin, 1996, heretofore known only from Tobago, is expanded based on specimens from islands offshore of eastern Venezuela.

Journey to the West: Trans-Pacific Historical Biogeography of Fringehead Blennies in the Genus Neoclinus (Teleostei: Blenniiformes).

Several temperate marine taxa of the northern hemisphere follow a trans-Pacific biogeographic track with representatives on either side of the intervening boreal waters. Shelter-dwelling blenniiform fishes of the genus Neoclinus exhibit this trans-Pacific distribution pattern with three species in the eastern North Pacific and eight species in the western North Pacific. We reconstructed the phylogeny of the Neocliniini (Neoclinus and the monotypic Mccoskerichthys) using six genetic markers: four mitochondrial genes (COI, cytochrome b, 12S and 16S), and two nuclear genes (RAG-1, TMO-4C4). Ancestral state reconstruction and molecular clock dating were used to explore hypothetical ancestral distributions and area relationships, and to estimate divergent times within this group. The monophyly of the genus Neoclinus, and the reciprocal monophyly of the eastern Pacific and western Pacific lineages were supported. Available evidence, including the eastern Pacific and western Atlantic occurrence of a New World clade of blennioid fishes that includes this lineage, supports the origin of the Neocliniini in the eastern Pacific with a single divergence event to the west across the North Pacific by the ancestor of the western Pacific clade. Estimated divergence time of the eastern and western Pacific clades of Neoclinus was 24.14 million year ago, which falls during the Oligocene epoch. Estimated times of divergence in other trans-Pacific lineages of marine fishes vary widely, from recent Pleistocene events to as early as 34 mya.

Fluctuating thermal environments of shallow-water rocky reefs in the Gulf of California, Mexico.

As part of a broad-scale study of the biogeography of rocky reefs in the Gulf of California, Mexico (GOC), we collected a continuous 1-yr temperature time series at ~5 m water depth at 16 sites spanning 5° of latitude and ~700 km along the western boundary of the basin. Throughout the region, thermal conditions were most variable in summer with fluctuations concentrated at diurnal and semi-diurnal frequencies, likely associated with solar and wind forcing and vertical water column oscillations forced by internal waves. Temperatures in winter were less variable than in summer, and minimum temperatures also differed among sites. Thermal variability integrated across the diurnal and semi-diurnal frequency bands was greatest near the Midriff Islands in the northern GOC and decreased toward the southern sites. Diurnal variability was greater than semi-diurnal variability at 13 of the 16 sites. A statistic-of-extremes analysis indicated shortest return times for cooling events in summer, and reef organisms at many of the sites may experience anomalous 2 to 5 °C cooling events multiple times per month. The significant extent of local temperature variability may play important roles in limiting species occurrences among sites across this biogeographic region.

Evolution of Sexual Dimorphism in Tube Blennies (Teleostei: Chaenopsidae).

The study of sexual differences provides insights into selective factors operating on males and females, especially for clades exhibiting varied levels of dimorphism. Sexual differences in morphology and coloration (melanophores) were compiled for 66 of the 89 species of tube blennies (Blenniiformes, Chaenopsidae) from the systematic literature and examination of preserved specimens. Chaenopsids include essentially monomorphic species and those in which males and females differ in as many as 17 morphological and 14 coloration features. While the sexes of most species differ in coloration (at least at the time of breeding), they are morphologically similar in Acanthemblemaria, Hemiemblemaria, and Lucayablennius. While other genera exhibit an intermediate level of dimorphism, species of Coralliozetus, Cirriemblemaria, and Emblemaria are dramatically dimorphic. Character maps on a phylogenetic hypothesis indicate that this extreme level of dimorphism evolved independently in these genera. A complex history of evolution is implied by examination of jaw length with both increases and decreases in one or both sexes leading to either dimorphism or monomorphism. Several features related to shelter defense are monomorphic in species where both sexes inhabit shelters, but dimorphic where only males occupy shelters. Other dimorphic features increase the conspicuousness of male courtship and aggressive displays.

Evolución del dimorfismo sexual en trambollos tubícolas (Teleostei: Chaenopsidae) (Evolution of sexual dimorphism in tube blennies [Teleostei: Chaenopsidae]) El estudio de las diferencias sexuales proporciona información sobre los factores selectivos que operan en hembras y machos especialmente para clados que muestran niveles variados de dimorfismo. Este estudio se enfocó en las diferencias sexuales en morfología y coloración de 66 especies de blenidos (Blenniiformes, Chaenopsidae). Para lo anterior se analizaron datos provenientes de literatura existente y el análisis de especímenes conservados. Los trambollos tubícolas incluyen especies esencialmente monomórficas y aquellas en las que los machos y las hembras difieren en 17 características morfológicas y 14 de coloración. Si bien los sexos de la mayoría de las especies difieren en la coloración (al menos en el momento de la reproducción), son morfológicamente similares en Acanthemblemaria, Hemiemblemaria, y Lucayablennius. Mientras que otros géneros exhiben un nivel intermedio de dimorfismo, las especies de Coralliozetus, Cirriemblemaria, y Emblemaria poseen un elevado dimorfismo sexual. La hipótesis filogenética indica que este nivel extremo de dimorfismo evolucionó independientemente en estos géneros. Al analizar la longitud de la mandíbula con aumentos y disminuciones en uno o ambos sexos que conducen a dimorfismo o monomorfismo se infiere una compleja historia evolutiva. Varias características relacionadas con la defensa del refugio son monomorfas en especies donde ambos sexos habitan en refugios, pero dimorfa donde solo los machos ocupan refugios. Otras características dimórficas aumentan la visibilidad del cortejo masculino y las exhibiciones agresivas. Translated to Spanish by S. Hinojosa (hinojosa.silvia@gmail.com).

Evolução do dimorfismo sexual em blennies tubulares (Teleostei: Chaenopsidae) (Evolution of sexual dimorphism in tube blennies [Teleostei: Chaenopsidae]) Estudo das diferenças sexuais provém novas idéias sobre fatores seletivos operando em machos e fêmeas, especialmente em clados que exibem níveis variados de dimorfismo. Diferenças sexuais na morfologia e coloração (melanofóros) foram compilados de 66 das 89 espécies de blennies tubulares (Blenniiformes, Chaenopsidae), examinando a literatura em sistemática e espécimes preservados. Chaenopídeos incluem espécies essencialmente monomórficas, além daquelas em que machos e fêmeas diferem em até 17 características morfológicas e 14 de coloração. Embora os sexos da maioria das espécies diferem em coloração (pelo menos no período de reprodução), eles são morfologicamente similares em Acanthemblemaria, Hemiemblemaria, e Lucayablennius. Enquanto outros gêneros exibem níveis intermediários de dimorfismo, espécies de Coralliozetus, Cirriemblemaria, e Emblemaria são dramaticamente dimórficas. Mapeamento de caracteres em uma hipótese filogenética indica que esses níveis extremos de dimorfismo surgiram independentemente nesses gêneros. Uma complexa história de evolução implica o envolvimento do comprimento das mandíbulas, com aumentos e reduções em um ou ambos sexos, levando ao dimorfismo ou monomorfismo. Diversas características relacionadas a defesa das tocas são monomórficas nas espécies em que ambos os sexos habitam tocas; mas nas espécies dimórficas, somente machos ocupam tocas. Outras características dimórficas aumentam a conspicuidade do cortejo masculino e demonstrações de agressividade. Translated to Portuguese by D. Vaz (dbistonvaz@vims.edu).

Heterochrony in fringeheads (Neoclinus) and amplification of an extraordinary aggressive display in the Sarcastic Fringehead (Teleostei: Blenniiformes).

The Sarcastic Fringehead (Neoclinus blanchardi, Teleostei) exhibits an extreme version of a common aggressive display, the "gaping display," in which an open mouth is presented toward an opponent. Males of this species have extremely long jaws that extend posteriorly well past the posterior margin of the head and are flared laterally during the gaping display. In this study, we explored morphological traits related to this extraordinary display in this and related species of blennies. Morphological modifications include enlargement of the buccopalatal membrane, elongation of the maxilla via an uncalcified posterior extension, and evolution of a novel hinge between the anterior maxilla and lacrimal bones permitting lateral movement of the upper jaw. Geometric morphometry using the truss network system, thin-plate spline, and PCA of three closely related species of Neoclinus indicate that the elongate maxilla of N. blanchardi most likely evolved via acceleration (faster growth compared to outgroups) and hypermorphosis (continued growth to a larger body size), both forms of peramorphic heterochrony. Coloration and fluorescence of the buccopalatal membrane may also serve to amplify the extraordinary gaping display of the Sarcastic Fringehead.

Molecular systematics of the New World clingfish genus Gobiesox (Teleostei: Gobiesocidae) and the origin of a freshwater clade.

The phylogenetic relationships between marine and freshwater members of the New World clingfish genus Gobiesox are investigated using both mitochondrial and nuclear sequence data. Phylogenetic hypotheses are derived from Bayesian and maximum parsimony analyses of a six-gene concatenated data set (2 mitochondrial and 4 nuclear markers; 4098bp). Gobiesox is paraphyletic, due to the inclusion of Pherallodiscus, in phylogenetic hypotheses resulting from all analyses and its two included species are reassigned to Gobiesox. Within the expanded genus Gobiesox, the freshwater species (G. cephalus, G. juradoensis, G. mexicanus and G. potamius) represent a monophyletic group that is nested inside of a paraphyletic marine group. Based on the monophyly of the freshwater clingfishes, a habitat transition from marine to freshwater is inferred to have occurred only once in the evolutionary history of the group (potentially in the mid-Miocene). Gobiesox is obtained as part of a larger clade of New World clingfishes, including also members of Acyrtops, Acyrtus, Arcos, Rimicola, Sicyases and Tomicodon equivalent to the subfamily Gobiesocinae. The phylogenetic hypotheses obtained are discussed briefly in relation to the two alternative classifications currently in use simultaneously for the Gobiesocidae. A rediagnosis and list of included species is provided for Gobiesox.

Gobiesox lanceolatus, a new species of clingfish (Teleostei: Gobiesocidae) from Los Frailes submarine canyon, Gulf of California, Mexico.

Gobiesox lanceolatus is described from a single specimen collected from 300 meters depth in the Los Frailes submarine canyon in the southwestern Gulf of California. The "Canyon Clingfish" is unique within Gobiesox in having a lanceolate caudal fin, with the central rays longer than those above and below them. It is also distinguished by 14 dorsal-fin rays (first tiny and unsegmented), 11 anal-fin rays, 28 pectoral-fin rays, anus slightly closer to anal-fin origin than to posterior margin of pelvic disc, and dorsal-fin origin in front of vertical from anus. It is most similar to Gobiesox eugrammus, known from Isla Guadelupe, the coast of outer Baja California and southern California. This is the deepest record for a species of Gobiesox and only four other species of clingfishes are known from greater depths.

Structure and mechanical implications of the pectoral fin skeleton in the Longnose Skate (Chondrichthyes, Batoidea).

Animal propulsion systems are believed to show high energy and mechanical efficiency in assisting movement compared to artificial designs. As an example, batoid fishes have very light cartilaginous skeletons that facilitate their elegant swimming via enlarged wing-like pectoral fins. The aim of this work is to illustrate the hierarchical structure of the pectoral fin of a representative batoid, the Longnose Skate (Raja rhina), and explain the mechanical implications of its structural design. At the macro level, the pectoral fins are comprised of radially oriented fin rays, formed by staggered mineralized skeletal elements stacked end-to-end. At the micro level, the midsection of each radial element is composed of three mineralized components, which consist of discrete segments (tesserae) that are mineralized cartilage and embedded in unmineralized cartilage. The radial elements are wrapped with aligned, unmineralized collagen fibers. This is the first report of the detailed structure of the ray elements, including the observation of a 3-chain mineralized tesserae. Structural analyses demonstrate that this configuration enhances stiffness in multiple directions. A two-dimensional numerical model based on the morphological analysis demonstrated that the tessera structure helps distributing shear, tensile and compressive stress more ideally, which can better support both lift and thrust forces when swimming without losing flexibility. STATEMENT OF SIGNIFICANCE: Batoid fishes have very light cartilaginous skeletons that facilitate their elegant swimming by applying their enlarged wing-like pectoral fins. Previous studies have shown structural features and mechanical properties of the mineralized cartilage skeleton in various batoid fishes. However, the details of the pectoral fin structure at different length scales, as well as the relationship between the mechanical properties and structural design remains unknown. The present work illustrates the hierarchical structure of the pectoral fin of the Longnose Skate (a representative batoid fish) and verifies the materials configuration and structural design increases the stiffness of fin skeleton without a loss in flexibility. These results have implications for the design of strong but flexible materials and bio-inspired autonomous underwater vehicles (AUVs).

The Effect of Background Music in Shark Documentaries on Viewers' Perceptions of Sharks.

Despite the ongoing need for shark conservation and management, prevailing negative sentiments marginalize these animals and legitimize permissive exploitation. These negative attitudes arise from an instinctive, yet exaggerated fear, which is validated and reinforced by disproportionate and sensationalistic news coverage of shark 'attacks' and by highlighting shark-on-human violence in popular movies and documentaries. In this study, we investigate another subtler, yet powerful factor that contributes to this fear: the ominous background music that often accompanies shark footage in documentaries. Using three experiments, we show that participants rated sharks more negatively and less positively after viewing a 60-second video clip of swimming sharks set to ominous background music, compared to participants who watched the same video clip set to uplifting background music, or silence. This finding was not an artifact of soundtrack alone because attitudes toward sharks did not differ among participants assigned to audio-only control treatments. This is the first study to demonstrate empirically that the connotative attributes of background music accompanying shark footage affect viewers' attitudes toward sharks. Given that nature documentaries are often regarded as objective and authoritative sources of information, it is critical that documentary filmmakers and viewers are aware of how the soundtrack can affect the interpretation of the educational content.

Annotated checklist of marine fishes from the Sanctuary of Bahía Chamela, Mexico with occurrence and biogeographic data.

An annotated checklist of marine fishes of the Sanctuary of Islands and Islets of Bahía Chamela in the central Mexican Pacific is presented. Records of fish species were obtained by different methods including visual census, sampling with anesthetics, fisherman-nets, and trawling with a biological dredge. Additional records were obtained from natural history collections and publications. The list comprises 196 species in 64 families and 141 genera. The Carangidae is the most speciose family with 11 species, followed by the Labridae with 10 and the Pomacentridae with nine. Fourteen species are endemic in Mexican Pacific waters, but none is restricted to Bahía Chamela. The most dominant species recorded during underwater surveys were Epinephelus labriformis, Stegastes flavilatus, and Halichoeres dispilus. Most species are of tropical affinities distributed throughout the tropical eastern Pacific (123), eastern Pacific (23), and Mexican Pacific (14). Other species are known from the eastern and Indo-Pacific regions (18), eastern Pacific and western Atlantic oceans (2), and some are circumtropical (9). A new record of the Gulf Brotula Ogilbia ventralis is provided for the Bahía Chamela and its geographical distribution is extended to Mexican central Pacific.

Olfaction Contributes to Pelagic Navigation in a Coastal Shark.

How animals navigate the constantly moving and visually uniform pelagic realm, often along straight paths between distant sites, is an enduring mystery. The mechanisms enabling pelagic navigation in cartilaginous fishes are particularly understudied. We used shoreward navigation by leopard sharks (Triakis semifasciata) as a model system to test whether olfaction contributes to pelagic navigation. Leopard sharks were captured alongshore, transported 9 km offshore, released, and acoustically tracked for approximately 4 h each until the transmitter released. Eleven sharks were rendered anosmic (nares occluded with cotton wool soaked in petroleum jelly); fifteen were sham controls. Mean swimming depth was 28.7 m. On average, tracks of control sharks ended 62.6% closer to shore, following relatively straight paths that were significantly directed over spatial scales exceeding 1600 m. In contrast, tracks of anosmic sharks ended 37.2% closer to shore, following significantly more tortuous paths that approximated correlated random walks. These results held after swimming paths were adjusted for current drift. This is the first study to demonstrate experimentally that olfaction contributes to pelagic navigation in sharks, likely mediated by chemical gradients as has been hypothesized for birds. Given the similarities between the fluid three-dimensional chemical atmosphere and ocean, further research comparing swimming and flying animals may lead to a unifying paradigm explaining their extraordinary navigational abilities.

Improved resolution and a novel phylogeny for the Neotropical triplefin blennies (Teleostei: Tripterygiidae).

The triplefin blennies (Teleostei: Tripterygiidae) are a diverse group of small-bodied benthic fishes associated with rocky or coral reefs. The Neotropics contain four genera and 26 species, many of which have only been recently described. A recent molecular phylogeny (Lin and Hastings, 2013) contrasts with previous phylogenies based on morphology in recovering the four Neotropical genera as a single clade with respect to the Indo-Pacific genera; however, relationships within and among genera were poorly resolved. This study reports a novel topology based on an expanded seven-loci molecular dataset. Individual gene trees have poor resolution, but concatenated analyses show strong support for most nodes, likely due to emergent support from concatenation. Consistent with Lin and Hastings (2013), three of the Neotropical genera, Axoclinus, Enneanectes, and Crocodilichthys, form a well-supported clade, but relationships of the fourth (Lepidonectes) are not confidently resolved. The monophyly of Axoclinus is well supported, but Enneanectes is paraphyletic with the inclusion of Axoclinus and Crocodilichthys. Improved resolution allows for reinterpretation of the biogeography of the Neotropical Tripterygiidae. Broader taxon sampling is still necessary for resolving the relationships within Tripterygiidae globally.

Chriolepis prolata, a new species of Atlantic goby (Teleostei: Gobiidae) from the North American continental shelf.

A new species of seven-spined goby of the genus Chriolepis is described from five specimens collected from the continental shelf of the northeastern Gulf of Mexico and Atlantic Ocean off South Carolina in depths of ca 54 to 110 m. The "Platform Goby", Chriolepis prolata, is distinguishable from all other western Atlantic species currently assigned to the genus Chriolepis and the morphologically similar genus Varicus in having pelvic-fin rays one through four branched, the fifth (innermost) pelvic-fin ray unbranched and relatively long (longer than the second ray to longer than all other pelvic-fin rays); most lateral body scales ctenoid, extending anteriorly in a wedge to a level anterior to the first dorsal-fin insertion or nearly to the pectoral-fin axil, with two or more rows of small cycloid scales extending anteriorly to near the pectoral-fin axil, cycloid scales along the bases of the dorsal and anal fins, and no scales on the belly; and the first two anal-fin pterygiophores inserted anterior to the first haemal spine. It closely resembles C. bilix but differs from that species which has a scaled belly, a shorter fifth pelvic-fin ray, prolonged dorsal-fin spines and smaller teeth in the lower jaw. An earlier report of C. bilix from Florida waters apparently refers to C. prolata.