Molecular confirmation of the occurrence of Anguilla interioris (Actinopterygii: Anguilliformes) in North Maluku of Indonesia and mitochondrial DNA haplotype diversity among existing specimens

Nineteen species of Anguilla Schrank, 1798 are globally distributed in the world, however knowledge on the biogeography, species diversity and ecology of the 13 species of tropical anguillids in the Indo-Pacific region is highly limited. This study examined the diversity of tropical anguillids found in North Maluku of East Indonesia, which is known to have unique and highly heterogeneous habitats, complex oceanography, high biodiversity, and representativeness of Asian and Australian fauna. By means of molecular identification, two tropical anguillid eels, A. marmorata Quoy & Gaimard, 1824 and A. interioris Whitely, 1938, were confirmed to be distributed in North Maluku. This study also examined the mitochondrial DNA haplotype diversity of A. interioris, as it could contribute to our understanding of the biogeography and life history of this eel species. Our molecular analyses showed the presence of the same haplotypes along the different locations in the Indo-Pacific region. Although more samples and DNA markers are required to provide more support, the results suggest that the larvae of A. interioris from potentially different spawning sites in the Indian and Pacific oceans could be mixed together due to the complexity of oceanic currents, and when these migrating larvae reach maturity, they would likely spawn with the local eels.

First record of cannibalism in the giant mottled eel Anguilla marmorata (Actinopterygii: Anguilliformes) as revealed by DNA barcoding

Although the giant mottled eel, Anguilla marmorata Quoy & Gaimard, 1824, is widely distributed in the Indo-Pacific region, few ecological studies have been conducted on the species. We investigated the stomach contents of A. marmorata visually and used the DNA-barcode region of the mitochondrial cytochrome c oxidase subunit 1 (CO1) to confirm the species identification. The stomach content analysis revealed that teleosts and crustaceans are the major prey items of A. marmorata. Interestingly, the stomach content of one of the specimens, which was 1029 mm in total length (TL), contained an eel-like fish identified as A. marmorata measuring 510 mm in TL. This study is the first to record cannibalism in the diet of A. marmorata. Although the diet of anguillid eels is generally selective for a single prey species, larger eels are more likely to adopt a diverse feeding habit that includes cannibalism in the tropical river ecosystems.(AU)

First record of cannibalism in the giant mottled eel Anguilla marmorata (Actinopterygii: Anguilliformes) as revealed by DNA barcoding

Although the giant mottled eel, Anguilla marmorata Quoy & Gaimard, 1824, is widely distributed in the Indo-Pacific region, few ecological studies have been conducted on the species. We investigated the stomach contents of A. marmorata visually and used the DNA-barcode region of the mitochondrial cytochrome c oxidase subunit 1 (CO1) to confirm the species' identification. The stomach content analysis revealed that teleosts and crustaceans are the major prey items of A. marmorata. Interestingly, the stomach content of one of the specimens, which was 1029 mm in total length (TL), contained an eel-like fish identified as A. marmorata measuring 510 mm in TL. This study is the first to record cannibalism in the diet of A. marmorata. Although the diet of anguillid eels is generally selective for a single prey species, larger eels are more likely to adopt a diverse feeding habit that includes cannibalism in the tropical river ecosystems.(AU)

DNA barcoding of a tropical anguillid eel, Anguilla bicolor (Actinopterygii: Anguilliformes), in Indo-Pacific region and notes on its population structure

The tropical anguillid eel, Anguilla bicolor McCelland, 1844, includes two subspecies, Anguilla bicolor bicolor McCelland, 1844 and Anguilla bicolor pacifica Schmidt, 1928, and is distributed across the Indo-Pacific region. Although A. bicolor is widely distributed and recognized as an important fish resource in the Indo-Pacific region, few studies have been conducted on its genetic variation and population structure. DNA barcoding of A. bicolor specimens collected in the Indo-Pacific region was carried out in this study using mitochondrial cytochrome c oxidase subunit I. Anguilla bicolor was found to diverge genetically, which supported its classification into two different subspecies. In addition, our study showed that A. bicolor bicolor had two genetically distinct populations/groups, and these different populations co-occur geographically in Indonesia and Malaysia in the eastern Indian Ocean. Our findings suggest that the eel larvae might be transported from at least two geographically different spawning grounds in the Indian Ocean, and then recruited to and settled in the same habitats in Indonesian and Malaysian waters. The molecular evidence calls for further research on the life history, stock assessment and protection of the populations of A. bicolor bicolor in Indonesia and Malaysia.

First record of cannibalism in the giant mottled eel Anguilla marmorata (Actinopterygii: Anguilliformes) as revealed by DNA barcoding

ABSTRACT Although the giant mottled eel, Anguilla marmorata Quoy & Gaimard, 1824, is widely distributed in the Indo-Pacific region, few ecological studies have been conducted on the species. We investigated the stomach contents of A. marmorata visually and used the DNA-barcode region of the mitochondrial cytochrome c oxidase subunit 1 (CO1) to confirm the species identification. The stomach content analysis revealed that teleosts and crustaceans are the major prey items of A. marmorata. Interestingly, the stomach content of one of the specimens, which was 1029 mm in total length (TL), contained an eel-like fish identified as A. marmorata measuring 510 mm in TL. This study is the first to record cannibalism in the diet of A. marmorata. Although the diet of anguillid eels is generally selective for a single prey species, larger eels are more likely to adopt a diverse feeding habit that includes cannibalism in the tropical river ecosystems.

DNA barcoding of a tropical anguillid eel, Anguilla bicolor (Actinopterygii: Anguilliformes), in Indo-Pacific region and notes on its population structure

The tropical anguillid eel, Anguilla bicolor McCelland, 1844, includes two subspecies, Anguilla bicolor bicolor McCelland, 1844 and Anguilla bicolor pacifica Schmidt, 1928, and is distributed across the Indo-Pacific region. Although A. bicolor is widely distributed and recognized as an important fish resource in the Indo-Pacific region, few studies have been conducted on its genetic variation and population structure. DNA barcoding of A. bicolor specimens collected in the Indo-Pacific region was carried out in this study using mitochondrial cytochrome c oxidase subunit I. Anguilla bicolor was found to diverge genetically, which supported its classification into two different subspecies. In addition, our study showed that A. bicolor bicolor had two genetically distinct populations/groups, and these different populations co-occur geographically in Indonesia and Malaysia in the eastern Indian Ocean. Our findings suggest that the eel larvae might be transported from at least two geographically different spawning grounds in the Indian Ocean, and then recruited to and settled in the same habitats in Indonesian and Malaysian waters. The molecular evidence calls for further research on the life history, stock assessment and protection of the populations of A. bicolor bicolor in Indonesia and Malaysia.(AU)

DNA barcoding of a tropical anguillid eel, Anguilla bicolor (Actinopterygii: Anguilliformes), in Indo-Pacific region and notes on its population structure

ABSTRACT The tropical anguillid eel, Anguilla bicolor McCelland, 1844, includes two subspecies, Anguilla bicolor bicolor McCelland, 1844 and Anguilla bicolor pacifica Schmidt, 1928, and is distributed across the Indo-Pacific region. Although A. bicolor is widely distributed and recognized as an important fish resource in the Indo-Pacific region, few studies have been conducted on its genetic variation and population structure. DNA barcoding of A. bicolor specimens collected in the Indo-Pacific region was carried out in this study using mitochondrial cytochrome c oxidase subunit I. Anguilla bicolor was found to diverge genetically, which supported its classification into two different subspecies. In addition, our study showed that A. bicolor bicolor had two genetically distinct populations/groups, and these different populations co-occur geographically in Indonesia and Malaysia in the eastern Indian Ocean. Our findings suggest that the eel larvae might be transported from at least two geographically different spawning grounds in the Indian Ocean, and then recruited to and settled in the same habitats in Indonesian and Malaysian waters. The molecular evidence calls for further research on the life history, stock assessment and protection of the populations of A. bicolor bicolor in Indonesia and Malaysia.

Organization of the cephalic lateral-line canals in Electrophorus varii de Santana, Wosiacki, Crampton, Sabaj, Dillman, Mendes-Júnior & Castro e Castro, 2019 (Gymnotiformes: Gymnotidae)

Electrophorus spp. generate high-voltage electric discharges for defense and hunting, and low-voltage electric discharges (as other Gymnotiformes) for electrolocation and communication. Despite intense interest in the unusual electrogenic and electroreceptive capacities of electric eels, the other sensory systems of Electrophorus spp. are relatively poorly known. Here we describe the ontogenetic development and organization of the cephalic lateral-line canals in the lowland electric eel, Electrophorus varii. Preserved specimens of larvae, juveniles, and adults were examined to describe the spatial distribution of the canals and pores. Ontogenetic shifts of the cephalic lateral line formation were observed for each canal and support a hypothesis of non-synchronized development. The morphogenesis of cephalic canals in larvae and juveniles begins just before the onset of exogenous feeding. In adults, the cephalic sensory canals are formed separately from the skull and overlay cranial and mandibular bones and muscles. This study provides the first detailed description of the development and organization of the cephalic lateral-line system in Electrophorus varii.(AU)

Electrophorus spp. geram descargas elétricas de alta voltagem, usadas para defesa e caça, e (como os demais Gymnotiformes) descargas elétricas de baixa voltagem para eletrolocalização e comunicação. Apesar do grande interesse nas capacidades eletrogênicas e eletrorreceptivas incomuns dos poraquês, os outros sistemas sensoriais de Electrophorus spp. são relativamente pouco conhecidos. Aqui nós descrevemos o desenvolvimento ontogenético e a organização dos canais da linha lateral cefálica no poraquê da planície Electrophorus varii. Exemplares preservados de larvas, juvenis e adultos foram analisados para descrever a distribuição espacial dos canais e poros. Variações ontogenéticas na formação da linha lateral cefálica foram observadas para cada canal, apresentando um desenvolvimento não-sincronizado. Variações ontogenéticas da formação da linha lateral cefálica foram observadas para cada canal e suportam uma hipótese de desenvolvimento assincrônico. A morfogênese dos canais cefálicos em larvas e juvenis precede o início da alimentação exógena. Nos adultos, os canais sensoriais cefálicos se formam separadamente do crânio e sobrepõem os ossos e músculos cranianos e mandibulares. Este estudo fornece a primeira descrição detalhada do desenvolvimento e organização do sistema da linha lateral cefálica de Electrophorus varii.(AU)

Organization of the cephalic lateral-line canals in Electrophorus varii de Santana, Wosiacki, Crampton, Sabaj, Dillman, Mendes-Júnior & Castro e Castro, 2019 (Gymnotiformes: Gymnotidae)

Electrophorus spp. generate high-voltage electric discharges for defense and hunting, and low-voltage electric discharges (as other Gymnotiformes) for electrolocation and communication. Despite intense interest in the unusual electrogenic and electroreceptive capacities of electric eels, the other sensory systems of Electrophorus spp. are relatively poorly known. Here we describe the ontogenetic development and organization of the cephalic lateral-line canals in the lowland electric eel, Electrophorus varii. Preserved specimens of larvae, juveniles, and adults were examined to describe the spatial distribution of the canals and pores. Ontogenetic shifts of the cephalic lateral line formation were observed for each canal and support a hypothesis of non-synchronized development. The morphogenesis of cephalic canals in larvae and juveniles begins just before the onset of exogenous feeding. In adults, the cephalic sensory canals are formed separately from the skull and overlay cranial and mandibular bones and muscles. This study provides the first detailed description of the development and organization of the cephalic lateral-line system in Electrophorus varii.(AU)

Electrophorus spp. geram descargas elétricas de alta voltagem, usadas para defesa e caça, e (como os demais Gymnotiformes) descargas elétricas de baixa voltagem para eletrolocalização e comunicação. Apesar do grande interesse nas capacidades eletrogênicas e eletrorreceptivas incomuns dos poraquês, os outros sistemas sensoriais de Electrophorus spp. são relativamente pouco conhecidos. Aqui nós descrevemos o desenvolvimento ontogenético e a organização dos canais da linha lateral cefálica no poraquê da planície Electrophorus varii. Exemplares preservados de larvas, juvenis e adultos foram analisados para descrever a distribuição espacial dos canais e poros. Variações ontogenéticas na formação da linha lateral cefálica foram observadas para cada canal, apresentando um desenvolvimento não-sincronizado. Variações ontogenéticas da formação da linha lateral cefálica foram observadas para cada canal e suportam uma hipótese de desenvolvimento assincrônico. A morfogênese dos canais cefálicos em larvas e juvenis precede o início da alimentação exógena. Nos adultos, os canais sensoriais cefálicos se formam separadamente do crânio e sobrepõem os ossos e músculos cranianos e mandibulares. Este estudo fornece a primeira descrição detalhada do desenvolvimento e organização do sistema da linha lateral cefálica de Electrophorus varii.(AU)

Coral and reef fish community recovery following the 2010 extreme ocean warming event (mass bleaching event) at Thailand

Reef fish play an important role in the community dynamics of coral reefs and maintaining healthy reefs. This study aimed to (1) assess coral recovery at reefs around Racha Yai Island after the 2010 mass coral bleaching event and (2) compare the fish community indices (Shannon diversity, evenness) and fish trophic functional groups between low (Patok Bay) and high (Khonkae Bay) environmental disturbance sites during 2013-2019. The fish surveys and the percent live coral covers from both bays during 2013-2019 were collected using the fish visual census method and a permanent quadrat method along 50-m transect lines. Our results showed that the percentage of live coral cover at both bays increased by 6-8%. At Khonkae Bay, there were 69 reef fish species and 10,684 individual fish belonging to 5 orders, with 27 families and 54 genera observed from 7 orders: Perciformes (91.03%), Tetraodontiformes (5.54%), Syngnathiformes (1.24%), Beloniformes (0.26%), Beryciformes (1.25%), Scorpaeniformes (0.70%), and Aulopiformes (0.06%). Fish community indices at Khonkae Bay increased during 2013-2019 and were composed of species richness (3.65-10.53), the Shannon index (0.65-3.49), and species evenness (0.49-0.91). At Patok Bay, there were 60 reef fish species and 10,362 individual fish belonging to 3 orders, with 22 families and 50 genera observed from 4 orders: Perciformes (93.04%), Tetraodontiformes (5.92%), Syngnathiformes (0.55%), and Anguilliformes (0.53%). Fish community indices at Patok Bay increased during 2014-2019 and were composed of species richness (4.69-8.62), the Shannon index (1.36-3.30), and species evenness (4.92-8.62). Our results suggested that the 2010 mass coral bleaching event had large impacts on both the coral and reef fish community at both low and high environmental disturbance sites with good recovery over nine years.(AU)

Coral and reef fish community recovery following the 2010 extreme ocean warming event (mass bleaching event) at Thailand

Reef fish play an important role in the community dynamics of coral reefs and maintaining healthy reefs. This study aimed to (1) assess coral recovery at reefs around Racha Yai Island after the 2010 mass coral bleaching event and (2) compare the fish community indices (Shannon diversity, evenness) and fish trophic functional groups between low (Patok Bay) and high (Khonkae Bay) environmental disturbance sites during 2013-2019. The fish surveys and the percent live coral covers from both bays during 2013-2019 were collected using the fish visual census method and a permanent quadrat method along 50-m transect lines. Our results showed that the percentage of live coral cover at both bays increased by 6-8%. At Khonkae Bay, there were 69 reef fish species and 10,684 individual fish belonging to 5 orders, with 27 families and 54 genera observed from 7 orders: Perciformes (91.03%), Tetraodontiformes (5.54%), Syngnathiformes (1.24%), Beloniformes (0.26%), Beryciformes (1.25%), Scorpaeniformes (0.70%), and Aulopiformes (0.06%). Fish community indices at Khonkae Bay increased during 2013-2019 and were composed of species richness (3.65-10.53), the Shannon index (0.65-3.49), and species evenness (0.49-0.91). At Patok Bay, there were 60 reef fish species and 10,362 individual fish belonging to 3 orders, with 22 families and 50 genera observed from 4 orders: Perciformes (93.04%), Tetraodontiformes (5.92%), Syngnathiformes (0.55%), and Anguilliformes (0.53%). Fish community indices at Patok Bay increased during 2014-2019 and were composed of species richness (4.69-8.62), the Shannon index (1.36-3.30), and species evenness (4.92-8.62). Our results suggested that the 2010 mass coral bleaching event had large impacts on both the coral and reef fish community at both low and high environmental disturbance sites with good recovery over nine years.

Occurrence and ecological implication of a tropical anguillid eel, Anguilla marmorata, in Brunei Darussalam, Borneo Island

Tropical anguillid eels account for two-thirds of the 19 species in Anguilla Schrank, 1798. However, information on the species diversity, geographical distribution, and life histories of the tropical eels is very limited. Recent studies suggested that morphological species identification of the tropical anguillid eels should be validated by molecular analysis for accurate identification. After surveying for three years, two anguillid eels were found in Brunei Darussalam, Borneo Island. They were firstly identified as Anguilla marmorata Quoy & Gaimard, 1824 using morphological analysis and further gene analysis of cytochrome c oxidase subunit I (COI) confirmed the species identification. This study is the first comprehensive description of A. marmorata in Brunei Darussalam, Borneo Island. Furthermore, it is also the first study to validate two anguillid eels collected from the tropical Bonin Islands of Japan as A. marmorata by means of morphological and COI analyses. The molecular phylogenetic tree and haplotype network analyses suggest that A. marmorata found in Brunei Darussalam would belong to the North Pacific population of the westernmost distribution.

Feeding ecology of electric eel Electrophorus varii (Gymnotiformes: Gymnotidae) in the Curiaú River Basin, Eastern Amazon

In this study, the composition of the diet and the feeding activity of Electrophorus varii were evaluated. The influence of ontogeny and seasonality in these feeding parameters was also examined. Fish were collected in the Curiaú River Basin, Amazon, Brazil, from March 2005 to February 2006, during the rainy (January-June) and dry (July-December) seasons. Diet composition was characterized based on the analysis of stomach contents and feeding dynamics was assessed based on the Stomach Fullness Index (IR) calculated using stomach weight. Stomach content and RI data were grouped into four-cm size classes (40-80, 80-120, 120-160, and 160-200) and two seasonal periods (rainy and dry). The influence of ontogeny and seasonality in the diet was investigated through PERMANOVA, and in the food dynamics through ANOVA. The analysis of stomach contents revealed that fish were the most consumed preys by electric eels, especially Callichthyidae and Cichlidae. Diet composition and RI values of electric eels were not influenced by ontogeny and seasonality. Electric eels are fish predators, regardless of size class and seasonal period.(AU)

Neste estudo foram avaliadas a composição da dieta e a atividade alimentar de Electrophorus varii. A influência da ontogenia e da sazonalidade nestes aspectos da alimentação dos poraquês também foi examinada. Os peixes foram coletados na Bacia do rio Curiaú, Amazônia, Brasil, no período de março de 2005 a fevereiro de 2006, abrangendo os períodos chuvoso (janeiro-junho) e o seco (julho-dezembro). A dieta foi avaliada por meio da análise dos conteúdos estomacais e a dinâmica alimentar por meio do Índice de Repleção Estomacal (RI) baseado nos dados de peso do estômago. Os dados do conteúdo estomacal e do RI foram agrupados em quatro classes de tamanho em cm (40-80, 80-120, 120-160 e 160-200) e dois períodos sazonais (chuvoso e seco). A influência da ontogenia e da sazonalidade na dieta foi investigada por meio da PERMANOVA, e na dinâmica alimentar por meio da ANOVA. A análise do conteúdo estomacal mostrou que os peixes foram as presas mais consumidas pelos poraquês, especialmente Callichthyidae e Cichlidae. A composição da dieta e os valores de RI dos poraquês não foram influenciadas pela ontogenia e pela sazonalidade. Os poraquês são predadores piscívoros, independente da classe de tamanho e do período sazonal.(AU)

Occurrence and ecological implication of a tropical anguillid eel, Anguilla marmorata, in Brunei Darussalam, Borneo Island

Tropical anguillid eels account for two-thirds of the 19 species in Anguilla Schrank, 1798. However, information on the species diversity, geographical distribution, and life histories of the tropical eels is very limited. Recent studies suggested that morphological species identification of the tropical anguillid eels should be validated by molecular analysis for accurate identification. After surveying for three years, two anguillid eels were found in Brunei Darussalam, Borneo Island. They were firstly identified as Anguilla marmorata Quoy & Gaimard, 1824 using morphological analysis and further gene analysis of cytochrome c oxidase subunit I (COI) confirmed the species identification. This study is the first comprehensive description of A. marmorata in Brunei Darussalam, Borneo Island. Furthermore, it is also the first study to validate two anguillid eels collected from the tropical Bonin Islands of Japan as A. marmorata by means of morphological and COI analyses. The molecular phylogenetic tree and haplotype network analyses suggest that A. marmorata found in Brunei Darussalam would belong to the North Pacific population of the westernmost distribution.(AU)

Feeding ecology of electric eel Electrophorus varii (Gymnotiformes: Gymnotidae) in the Curiaú River Basin, Eastern Amazon

In this study, the composition of the diet and the feeding activity of Electrophorus varii were evaluated. The influence of ontogeny and seasonality in these feeding parameters was also examined. Fish were collected in the Curiaú River Basin, Amazon, Brazil, from March 2005 to February 2006, during the rainy (January-June) and dry (July-December) seasons. Diet composition was characterized based on the analysis of stomach contents and feeding dynamics was assessed based on the Stomach Fullness Index (IR) calculated using stomach weight. Stomach content and RI data were grouped into four-cm size classes (40-80, 80-120, 120-160, and 160-200) and two seasonal periods (rainy and dry). The influence of ontogeny and seasonality in the diet was investigated through PERMANOVA, and in the food dynamics through ANOVA. The analysis of stomach contents revealed that fish were the most consumed preys by electric eels, especially Callichthyidae and Cichlidae. Diet composition and RI values of electric eels were not influenced by ontogeny and seasonality. Electric eels are fish predators, regardless of size class and seasonal period.(AU)

Neste estudo foram avaliadas a composição da dieta e a atividade alimentar de Electrophorus varii. A influência da ontogenia e da sazonalidade nestes aspectos da alimentação dos poraquês também foi examinada. Os peixes foram coletados na Bacia do rio Curiaú, Amazônia, Brasil, no período de março de 2005 a fevereiro de 2006, abrangendo os períodos chuvoso (janeiro-junho) e o seco (julho-dezembro). A dieta foi avaliada por meio da análise dos conteúdos estomacais e a dinâmica alimentar por meio do Índice de Repleção Estomacal (RI) baseado nos dados de peso do estômago. Os dados do conteúdo estomacal e do RI foram agrupados em quatro classes de tamanho em cm (40-80, 80-120, 120-160 e 160-200) e dois períodos sazonais (chuvoso e seco). A influência da ontogenia e da sazonalidade na dieta foi investigada por meio da PERMANOVA, e na dinâmica alimentar por meio da ANOVA. A análise do conteúdo estomacal mostrou que os peixes foram as presas mais consumidas pelos poraquês, especialmente Callichthyidae e Cichlidae. A composição da dieta e os valores de RI dos poraquês não foram influenciadas pela ontogenia e pela sazonalidade. Os poraquês são predadores piscívoros, independente da classe de tamanho e do período sazonal.(AU)

Record of the rare Caribbean mud eel, Pythonichthys sanguineus (Heterenchelyidae, Anguilliformes), in the region of the Amazon Reef / Registro da rara enguia de lama do Caribe, Pythonichthys sanguineus (Heterenchelyidae, Anguilliformes) na região dos Recifes da Amazônia

As they spend most of their time buried in the substrate and are not a fishery resource, heterenchelyids are seldom seen. These eels are characterized by their greatly reduced eyes, which are covered by semi-transparent skin, the absence of a pectoral fin or lateral line, and no pores on the head or body. Pythonichthys sanguineus is a particularly poorly-known species, with only eight scientific records from Cuba, Puerto Rico, Colombia, Venezuela, Guyana, and Suriname. The present study is based on six adult specimens of P. sanguineus captured by vessels of the shrimp trawling fleet along the northern Brazilian coast, in the vicinity of the Amazon Reef. We provide meristic, morphometric and DNA barcoding data. These findings provide insights into the distribution of the species off the northern Brazilian coast and contribute to the discussion about the southern limit of the Greater Caribbean fauna. (AU)

Heterenchelídeos passam a maior parte do tempo enterrados no substrato e raramente são vistos, não representando recursos pesqueiros importantes. Essas enguias são caracterizadas por seus olhos muito reduzidos e cobertos por pele semi-transparente, ausência de nadadeiras peitorais ou linha lateral, e ausência de poros na cabeça ou no corpo. Pythonichthys sanguineus é uma espécie particularmente pouco conhecida, com apenas oito registros em coleção zoológica para Cuba, Porto Rico, Colômbia, Venezuela, Guiana e Suriname. O presente estudo é baseado em seis espécimes adultos de P. sanguineus capturados pela frota industrial de arrasto de camarão-rosa na costa norte do Brasil, ao largo dos Recifes da Amazônia. Apresentamos dados merísticos, morfométricos e de DNA barcoding dos exemplares examinados. O registro fornece informações importantes sobre a distribuição da espécie na costa norte do Brasil, e contribui para a discussão sobre o limite sul da fauna do Grande Caribe.(AU)

Record of the rare Caribbean mud eel, Pythonichthys sanguineus (Heterenchelyidae, Anguilliformes), in the region of the Amazon Reef / Registro da rara enguia de lama do Caribe, Pythonichthys sanguineus (Heterenchelyidae, Anguilliformes) na região dos Recifes da Amazônia

As they spend most of their time buried in the substrate and are not a fishery resource, heterenchelyids are seldom seen. These eels are characterized by their greatly reduced eyes, which are covered by semi-transparent skin, the absence of a pectoral fin or lateral line, and no pores on the head or body. Pythonichthys sanguineus is a particularly poorly-known species, with only eight scientific records from Cuba, Puerto Rico, Colombia, Venezuela, Guyana, and Suriname. The present study is based on six adult specimens of P. sanguineus captured by vessels of the shrimp trawling fleet along the northern Brazilian coast, in the vicinity of the Amazon Reef. We provide meristic, morphometric and DNA barcoding data. These findings provide insights into the distribution of the species off the northern Brazilian coast and contribute to the discussion about the southern limit of the Greater Caribbean fauna.(AU)

Heterenchelídeos passam a maior parte do tempo enterrados no substrato e raramente são vistos, não representando recursos pesqueiros importantes. Essas enguias são caracterizadas por seus olhos muito reduzidos e cobertos por pele semi-transparente, ausência de nadadeiras peitorais ou linha lateral, e ausência de poros na cabeça ou no corpo. Pythonichthys sanguineus é uma espécie particularmente pouco conhecida, com apenas oito registros em coleção zoológica para Cuba, Porto Rico, Colômbia, Venezuela, Guiana e Suriname. O presente estudo é baseado em seis espécimes adultos de P. sanguineus capturados pela frota industrial de arrasto de camarão-rosa na costa norte do Brasil, ao largo dos Recifes da Amazônia. Apresentamos dados merísticos, morfométricos e de DNA barcoding dos exemplares examinados. O registro fornece informações importantes sobre a distribuição da espécie na costa norte do Brasil, e contribui para a discussão sobre o limite sul da fauna do Grande Caribe.(AU)

First record of Aplatophis chauliodus (Actinopterygii: Ophichthidae) for the northeatern coast of Brazil, with expansion of its geographic range

We expanded its geographical distribution to the south by more than 3,000 km. Some variations were observed in relation to body proportions in the present study, thus contributing to a better knowledge about A. chauliodus, which is still little known in its more distinct aspects as well as little represented in the material housed in scientific collections.(AU)

Ampliamos em mais de 3.000 km sua distribuição geográfica ao Sul. Algumas variações foram observadas em relação às proporções corporais no presente estudo, contribuindo assim para um melhor conhecimento sobre A. chauliodus, que ainda é pouco conhecido em seus aspectos mais distintos, bem como rara em coleções científicas.(AU)

First record of Aplatophis chauliodus (Actinopterygii: Ophichthidae) for the northeatern coast of Brazil, with expansion of its geographic range

We expanded its geographical distribution to the south by more than 3,000 km. Some variations were observed in relation to body proportions in the present study, thus contributing to a better knowledge about A. chauliodus, which is still little known in its more distinct aspects as well as little represented in the material housed in scientific collections.

Ampliamos em mais de 3.000 km sua distribuição geográfica ao Sul. Algumas variações foram observadas em relação às proporções corporais no presente estudo, contribuindo assim para um melhor conhecimento sobre A. chauliodus, que ainda é pouco conhecido em seus aspectos mais distintos, bem como rara em coleções científicas.

On the taxonomic status of three eels (Teleostei: Anguilliformes) described from Leptocephali by Tommasi (1960)

The taxonomic status of three species of eels described from leptocephali larvae in 1960, is revised and elucidated: Leptocephalus anaelisae Tommasi, 1960, a member of Moringuidae, is confirmed as a junior synonym of Neoconger mucronatus Girard, 1858; Leptocephalus juliae Tommasi, 1960, a Muraenidae, is confirmed as a junior synonym of Uropterygius macularius (Lesueur, 1825); and Leptocephalus humbermariorum Tommasi, 1960, a Congridae, is now placed as species inquirenda in Rhynchoconger Jordan & Hubbs, 1925. Each of the three species was described based on a unique holotype, but none of the tree holotypes were found in any scientific collection investigated by us. Indeed, the three holotypes are considered to be permanently lost.