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Chimaeras, fish in the order Chimaeriformes, are among the rarest and least studied fish in the class Chondrichthyes (cartilaginous fish). Previous records have indicated that a species of chimaera known as the elephantfish, or cockfish, Callorhinchus callorynchus, may be found in marine waters off southeastern Brazil, as far north as the state of Sao Paulo. Here we report that C. callorynchus, caught with bottom gillnet, was found in an urban fish market in the city of Rio de Janeiro (~23˚S). This and other records from a variety of places call into question the distribution limits of the American elephantfish in the southwestern Atlantic Ocean and whether, at least seasonally, this species may often be found as far north as the state of Rio de Janeiro. Because of scientific and conservation interests in the poorly known Chimaeriformes, we recommend long-term monitoring of the fish catch in ports along the southern Brazilian coast, to better understand the natural history of the intriguing chimeras.

Los hábitos alimentarios de Callorhinchus callorynchus fueron investigados en las aguas costeras del norte de Argentina. Se evaluó el efecto del tamaño del cuerpo, la temporada y la región sobre la composición de la dieta de las hembras mediante un enfoque de modelado de múltiples hipótesis. Callorhinchus callorynchus se alimentó principalmente de bivalvos (55,61% PSIRI), seguido de cangrejos brachyuras (10,62% PSIRI) y de isópodos (10,13% PSIRI). Las hembras de C. callorynchus presentaron cambios en la dieta con incremento del tamaño del cuerpo, la temporada y la región. Además, esta especie es capaz de consumir bivalvos de mayor tamaño a medida que incrementa el tamaño del cuerpo. El nivel trófico fue calculado en 3,15, caracterizando a esta especie como un consumidor secundario. Concluimos que C. callorynchus presentó un comportamiento de triturador de presas duras, principalmente bivalvos, cangrejos y gasterópodos. Las hembras de esta especie cambian su dieta con el incremento del tamaño del cuerpo y en respuesta a cambios temporales y regionales en la abundancia y distribución de sus presas. The feeding habits of Callorhinchus callorynchus were investigated in coastal waters off northern Argentina. The effect of body size, seasons and regions was evaluated on female diet composition using a multiple-hypothesis modelling approach. Callorhinchus callorynchus fed mainly on bivalves (55.61% PSIRI), followed by brachyuran crabs (10.62% PSIRI) and isopods (10.13% PSIRI). Callorhinchus callorynchus females showed changes in the diet composition with increasing body size and also between seasons and regions. Further, this species is able to consume larger bivalves as it grows. Trophic level was 3.15, characterizing it as a secondary consumer. We conclude that C. callorynchus showed a behavior of crushing hard prey, mainly on bivalves, brachyuran, gastropods and anomuran crabs. Females of this species shift their diet with increasing body size and in response to seasonal and regional changes in prey abundance or distribution. Fil: Roman, Jorge Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Chierichetti, Melisa Antonela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Barbini, Santiago Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Scenna, Lorena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Organic contaminants are of great environmental concern due to their negative impacts on coastal ecosystems, especially on highly vulnerable species as chondrichthyans. Accumulation of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and chlorpyrifos was assessed in muscle, gonads, and liver of the cockfish Callorhinchus callorynchus for both sexes and maturity stages. This species has a wide distribution in South Atlantic Ocean and it is an important resource for coastal Argentine fisheries. Pollutants were quantified by gas chromatography with electron capture detector and the distribution pattern found in C. callorynchus was the following: (∑OCPs+chlorpyrifos) > ∑PCBs>∑PBDEs. Endosulfan was predominant among OCP groups, penta-CBs and hexaCBs among PCBs and BDE 47, 66, 99, and 100 in PBDE group. The highest levels were found in liver followed by muscle and gonads. The highest percentage of lipids was also observed in the liver. Moreover, the concentrations of ∑OCPs and ∑PCBs in C. callorynchus liver varied with maturity stage, and ∑OCPs also with sexes. Females presented higher values than males, and mature individuals showed higher concentrations than immature ones, according with biological parameters such as age, sex, maturity stage, metabolic and redistribution processes and habitat use influence. These results indicate that C. callorynchus reflects a historical and recent contamination in their tissues, and therefore, especially females, becomes as a good biomonitor of these pollutants in the marine environment. To our knowledge, this work represents one of the few investigations on the occurrence of POPs and chlorpyrifos in chondrichtyans from South Atlantic Ocean; therefore more research is mandatory for an adequate management and conservation of existing fisheries and aquatic resources.

In this paper the occurrence of two specimens of the elephant fish, Callorhinchus callorynchus is recorded. Despite of the fact of being common off Uruguay and Argentina, the species is occasionally caught in South Brazil. As a consequence, information on the populations of this species is not available.

Conocer los parámetros de historia de vida de las especies de condrictios es uno de los principales requisitos para evaluar el estado de sus poblaciones y vulnerabilidad a la explotación pesquera. En este estudio se estimó el crecimiento en longitud, la talla de madurez (LM50%), la longevidad (Emax) y la tasa de mortalidad natural (M) del pez gallo, Callorhinchus callorynchus, en el Golfo San Matías, Argentina. En los muestreos de las capturas comerciales se obtuvo un rango de tallas de 22 a 58 cm para machos y de 25 a 76 cm para las hembras, mientras que en las campañas de investigación fue de 13 a 59 cm para los machos y de 14 a 69 cm para las hembras. La proporción de sexos estuvo sesgada hacia los machos. El modelo de crecimiento de Gompertz L0 fijo fue el más adecuado según el criterio biológico de selección. Los parámetros fueron: i) hembras: L∞= 70,75 cm y K= 0,17 año-1; ii) machos: L∞= 56,11 cm y K= 0,257 año-1. Para machos se obtuvo un LM50%= 43,39 cm, una Emax= 13,7 años y una Mmedia= 0,35 año-1 y para hembras se obtuvo un LM50%= 47,48 cm, una Emax= 21,4 años y una Mmedia= 0,23 año-1. Los resultados de este estudio indican que existe dimorfismo sexual en la especie, siendo las hembras las que alcanzan mayor talla, maduran más tarde, crecen más lento y son más longevas que los machos.

The catch per unit of effort (CPUE) data of cockfish, Callorhinchus callorynchus, during 1986-2011 was evaluated for the bottom trawl fishery of the San Matías gulf (Patagonia, Argentina). The objective of this work was to detect what are the factors related to fishery dynamic that affect catch rate of cockfish and to assess standardized CPUE by General linear models (GLMs) and General linear mixed models (GLMMs) as a relative abundance index. The annual trend of the catch rate indicated an increase during the evaluated period. The nominal CPUE and the indices standardized by the Delta-GLM and Delta-GLMM showed the same annual trend, with increases of 57%, 61.1% and 60.7%, respectively. The LogNormal models have the best-fit model and explained 23.5% of the total variability. The factors year, month, depth and hake CPUE explained the highest variability. The analysis of the models indicated that the catch rate of cockfish is subject to the lack of an homogeneous distribution of the fishing effort during different years, months and vessels. This was related to the fleet dynamic searching the targets species. The increasing trend of CPUE and landings would be indicating an increase in effort directionality to the cockfish in the last decade. Resumo Dados de captura por unidade de esforço (CPUE) do peixe-galo Callorhinchus callorynchus foram avaliados para a pesca de arrasto de fundo no Golfo de San Matías (Patagonia, Argentina), durante o período 1986-2011. Os objetivos do trabalho foram identificar quais os fatores relacionados à dinâmica pesqueira que afetam a taxa de captura do peixe-galo e verificar a viabilidade em utilizar dados de CPUEs padronizadas pelos Modelos Lineares Gerais (GLM) e Modelos Lineares Gerais Mistos (GLMMs) como índices de abundância relativa. A tendência anual da taxa de captura indicou um aumento durante o período avaliado. A CPUE nominal e os índices padronizados pelo Delta-GLM e Delta-GLMM apresentaram a mesma tendência anual, com aumentos de 57%, 61.1% e 60.7%, respectivamente. Os modelos LogNormal foram os de melhor ajuste e explicaram 23,5% da variabilidade total dos dados. Ano, mês, profundidade e "hake" CPUE foram os fatores mais explicativos. A análise dos modelos indicou que a taxa de captura do peixe-galo está ligada à falta de distribuição homogênea do esforço de pesca durante os diferentes anos, meses e navios. Este fato esteve relacionado à dinâmica das frotas na busca das espécies alvo. A tendência crescente no aumento das CPUE e descargas em terra estaria indicando a mudança do esforço de pesca direcionado ao peixe-galo na última década.

Here we present a mitogenomic perspective on the evolution of sharks and rays, being a first glance on the complete mitochondrial history of such an old and diversified group of vertebrates. The Elasmobranchii is a diverse subclass of Chondrichthyes, or cartilaginous fish, with about 1200 species of ocean- and freshwater-dwelling fishes spread all over the world’s seas, including some of the ocean’s largest fishes. The group dates back about 400 million years near the Devonian–Silurian boundary, being nowadays represented by several derivative lineages, mainly related to Mesozoic forms. Although considered of ecological, commercial and conservation importance, the phylogeny of this old group is poorly studied and still under debate. Here we apply a molecular systematic approach on 82 complete mitochondrial genomes to investigate the phylogeny of the Elasmobranchii. By using maximum likelihood (ML) and Bayesian analyses, we found a clear separation within the shark clade between the Galeomorphii and the Squalomorphii, as well as sister taxa relationships between the Carcharhiniformes and the Lamniformes. Moreover, we found that Pristoidei clusters within the Rhinobatoidei, having been recovered as the sister taxon of the Rhinobatos genus in a clade which also includes the basal Zapteryx. Our results also reject the Hypnosqualea hypothesis, which proposes that the Batoidea should be placed within the Selachii. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group. This study was supported by Coordenac¸ão de Aperfeic¸oamento de Pessoal de Ńıvel Superior (CAPES), Fundac¸ão Carlos Chagas Filho de Amparo àPesquisa do Estado do Rio de Janeiro, FEDER-Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020-Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT-Fundac¸ão para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovac¸ão in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274). FP was supported by Investigator FCT (IF/01356/2012) and MARINFO (NORTE-01-0145-FEDER-000031).

The cockfish, Callorhinchus callorynchus, is a widely distributed holocephalan in the south-western Atlantic and an important resource for Argentinean fisheries. The reproductive characteristics of this species were studied in northern Argentinean coastal waters, where specimens arrive seasonally (winter-spring). Sexual dimorphism in maximum precaudal length (PCL) and total body mass (TM) was found, being females (PCL=630 mm; TM=3330 g; n=167) larger and heavier than males (PCL=482 mm; TM=1630 g; n=19). Maturity size for females was 466.22 mm PCL, representing 74% PCL of the largest female sampled. The mean number of ovarian follicles was 8.37 (± 4.84). The highest values of ovarian follicles diameter, gonadosomatic and oviducalsomatic indices were found in spring. A high proportion of mature females (44%) had atretic ovarian follicles, suggesting that they were in the resting stage of their reproductive cycle. The low number of mature males recorded and the absence of mature females with spermatophore masses or egg cases indicate that the study area would not be a reproductive zone. The seasonal presence of C. callorynchus in this region could be related to trophic movements. These results, obtained in an area with high fishing pressure on chondrichthyans, will be useful for implementing conservation and management measures. Fil: Chierichetti, Melisa Antonela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Scenna, Lorena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Di Giacomo, Edgardo Ernesto. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: Ondarza, Paola Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Figueroa, Daniel Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Miglioranza, Karina Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

The San Matias Gulf (SMG; 41°- 42° S; 64°- 65° W) is the largest gulf in Northern Patagonia, Argentina. Up to date, the chondrichthyan fauna of this area has not been reported. Therefore, the aim of this work is to provide a list with species presence and biological characteristics of the chondrichthyans recorded in SMG during the last 30 years. A total of 13 sharks distributed in 11 families, 19 skates and rays distributed in six families, and one holocephalan have been so far recorded in SMG. From the zoogeographical point of view, this chondrichthyan fauna is a mixed assemblage of species typically found in the Argentinean and Magellanean Provinces. The holocephalan Callorhinchus callorynchus is the most landed chondricthyan of the local fishery. With it, five sharks and seven skates are also exploited.

The distribution limits in the Atlantic of Callorhinchus callorynchus (Callorhinchidae) and Odontesthes argentinensis (Atherinopsidae) are extended northwards to 22° 22' S and 22° 31' S, respectively, whereas that of Lile piquitinga (Clupeidae) is extended southwards to 22° 22' S. Their occurrence in the north of Rio de Janeiro State is discussed. Remarks on the osteology of O. argentinensis, and morphometric and meristic data of L. piquitinga, are also provided.

Redescriptions are provided for Callorhynchicola branchialis and C. multitesticulatus (Monogenea: Chimaericolidae) found on Callorhinchus callorynchus and on C. milii and C. capensis, respectively. In particular, the sclerotised components of the haptor are described with reference to the larval haptor. Prevalence and intensity data for Callorhynchicola multitesticulatus on Callorhinchus milii taken off the east coast of New Zealand (South Island) are included. Homologies of the haptoral sclerites are discussed and a preliminary comment on the phylogenetic significance of the configuration of the haptoral sclerites is provided.

*Laboratorio de Ictiologia, Departamento de Ciencias Marinas, Universidad Nacional de Mar del Plata (UNMdP), Argentina. †Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET). ‡Museo del Mar, Mar del Plata, Argentina. ∫Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CIC). §Instituto Nacional de Investigacion y Desarrollo Pesquero (INIDEP). ¶Corresponding author, e-mail: blasina@mdp.edu.ar

Un pez elefante se reporta por la primera vez del Ecuador continental. Un solo especimen del pejegallo suramericano comun, Callorhinchus callorynchus, fue recogido en Puerto Lopez en 1998. Este registro corresponde a una extension del rango de distribucion hacia el norte de por lo menos 500 km. Su ocurrencia en Ecuador podria ser ligada al acontecimiento de La Nina 1998-2001.

Un pez elefante se reporta por la primera vez del Ecuador continental. Un solo espécimen del pejegallo suramericano común, Callorhinchus callorynchus, fue recogido en Puerto López en 1998. Este registro corresponde a una extensión del rango de distribución hacia el norte de por lo menos 500 km. Su ocurrencia en Ecuador podría ser ligada al acontecimiento de La Niña 1998-2001.

The retina of the elephant fish,Callorhinchus callorynchus, was found to have a vitamin A1-based photopigment with maximum absorbance at 499 nm. The spectral location of this photopigment is significant because this chimaeroid fish is not known to inhabit deep water but has been found in shallow water, often in river mouths. Compared to the findings inHydrologus affinis, a deep-water chimaeroid with a P4771, andHydrolagus colliei, a vertical migrating chimaeroid which has been found in both shallow and deep water, and which has a P4841, the finding inCallorhinchus of a P4991 suggests that in the holocephalans, as in other elasmobranchs and in teleosts, there has evolved a visual pigment system adaptive to the quality of the photic environment.