Two new, remarkably colored species of the Neotropical catfish genus Cetopsorhamdia Eigenmann & Fisher, 1916 (Siluriformes, Heptapteridae) from Chapada dos Parecis, western Brazil, with an assessment of the morphological characters bearing on their phylogenetic relationships

Abstract Two new species of heptapterid catfish genus Cetopsorhamdia are described from close localities in western Brazil, at Chapada dos Parecis, an area with extremely high level of endemism. One species is from the upper Rio Madeira system, Rondônia State, and the other from the upper Rio Tapajós system, Mato Grosso State. The two species are diagnosed, among several other features, by their markedly distinctive color patterns, with the former having well-defined quadrangular marks in trunk flanks while the latter bearing irregular, vertical bars along the trunk. The monophyly of Cetopsorhamdia is discussed, with two putative synapomorphies being proposed to support the genus. Potentially informative morphological characters to resolve the internal relationships of the genus are presented and discussed. Despite the striking external differences between the two species herein described, they are found to likely form a clade.

The rediscovery of Pimelodella longipinnis (Borodin, 1927), an enigmatic Atlantic Rainforest catfish species from Southeastern Brazil (Siluriformes: Heptapteridae)

Abstract This article is a redescription of Pimelodella longipinnis, an enigmatic catfish previously known only from its holotype and with uncertain type locality. The species is redescribed based on recently collected materials from streams of the Mata Atlântica bioregion, in Santos municipality, São Paulo State, Brazil. Pimelodella longipinnis is assigned to a putatively monophyletic group, the Pimelodella leptosoma-group, diagnosed by the presence of a supraoccipital process not reaching the anterior nuchal plate, with a gap of ca. 20-25% of the supraoccipital process total length, and whose tip notably surpasses the midpoint of the complex vertebra in dorsal view. We also present a list of fish species described from a shipping sent to the American Museum of Natural History from the former Museu Paulista (now Museu de Zoologia da Universidade de São Paulo), of which P. longipinnis was part.

Two new, remarkably colored species of the Neotropical catfish genus Cetopsorhamdia Eigenmann & Fisher, 1916 (Siluriformes, Heptapteridae) from Chapada dos Parecis, western Brazil, with an assessment of the morphological characters bearing on their phylogenetic relationships

Abstract Two new species of heptapterid catfish genus Cetopsorhamdia are described from close localities in western Brazil, at Chapada dos Parecis, an area with extremely high level of endemism. One species is from the upper Rio Madeira system, Rondônia State, and the other from the upper Rio Tapajós system, Mato Grosso State. The two species are diagnosed, among several other features, by their markedly distinctive color patterns, with the former having well-defined quadrangular marks in trunk flanks while the latter bearing irregular, vertical bars along the trunk. The monophyly of Cetopsorhamdia is discussed, with two putative synapomorphies being proposed to support the genus. Potentially informative morphological characters to resolve the internal relationships of the genus are presented and discussed. Despite the striking external differences between the two species herein described, they are found to likely form a clade.

The rediscovery of Pimelodella longipinnis (Borodin, 1927), an enigmatic Atlantic Rainforest catfish species from Southeastern Brazil (Siluriformes: Heptapteridae)

Abstract This article is a redescription of Pimelodella longipinnis, an enigmatic catfish previously known only from its holotype and with uncertain type locality. The species is redescribed based on recently collected materials from streams of the Mata Atlântica bioregion, in Santos municipality, São Paulo State, Brazil. Pimelodella longipinnis is assigned to a putatively monophyletic group, the Pimelodella leptosoma-group, diagnosed by the presence of a supraoccipital process not reaching the anterior nuchal plate, with a gap of ca. 20-25% of the supraoccipital process total length, and whose tip notably surpasses the midpoint of the complex vertebra in dorsal view. We also present a list of fish species described from a shipping sent to the American Museum of Natural History from the former Museu Paulista (now Museu de Zoologia da Universidade de São Paulo), of which P. longipinnis was part.

Pectoral-fin glands and delivery apparatus in the catfish genus Brachyrhamdia Myers, 1927 (Siluriformes: Heptapteridae)

Abstract The Siluriformes, popularly known as catfishes, are probably the vertebrate group with the highest diversity of venomous animals, even though only approximately a hundred venomous catfishes are reported to date. Venomous catfishes might present a delivery system apparatus, formed by an unbranched ray at the leading edge of pectoral and dorsal fins (spine), which can be stiffened and pungent, while venom glands can be present at the surface of such spines and/or the axillary region. This work investigated the presence, morphology and distribution of glands and pectoral-fin delivery apparatus in the heptapterid Brachyrhamdia genus. Pectoral-fin spine external morphology was compared across all valid species in the genus, histological sections of the pectoral-fin spine and axillary regions of B. heteropleura and B. marthae were produced, and dissections of the pectoral girdle region of the mentioned species were analyzed. The histological sections confirmed the presence of pectoral-fin glands at the surface of the pectoral-fin spine of Brachyrhamdia species, and cellular morphology indicates these glands are probably venomous. Also, we found a piriform gland at the axillary region, whose cell morphology is like the reported for other catfishes. However, we cannot currently confirm or deny axillary gland participation in the venom delivery apparatus. This work constitutes the first report of venom glands in Brachyrhamdia, and the first description of Heptapteridae axillary glands.

Pectoral-fin glands and delivery apparatus in the catfish genus Brachyrhamdia Myers, 1927 (Siluriformes: Heptapteridae)

Abstract The Siluriformes, popularly known as catfishes, are probably the vertebrate group with the highest diversity of venomous animals, even though only approximately a hundred venomous catfishes are reported to date. Venomous catfishes might present a delivery system apparatus, formed by an unbranched ray at the leading edge of pectoral and dorsal fins (spine), which can be stiffened and pungent, while venom glands can be present at the surface of such spines and/or the axillary region. This work investigated the presence, morphology and distribution of glands and pectoral-fin delivery apparatus in the heptapterid Brachyrhamdia genus. Pectoral-fin spine external morphology was compared across all valid species in the genus, histological sections of the pectoral-fin spine and axillary regions of B. heteropleura and B. marthae were produced, and dissections of the pectoral girdle region of the mentioned species were analyzed. The histological sections confirmed the presence of pectoral-fin glands at the surface of the pectoral-fin spine of Brachyrhamdia species, and cellular morphology indicates these glands are probably venomous. Also, we found a piriform gland at the axillary region, whose cell morphology is like the reported for other catfishes. However, we cannot currently confirm or deny axillary gland participation in the venom delivery apparatus. This work constitutes the first report of venom glands in Brachyrhamdia, and the first description of Heptapteridae axillary glands.

Two new catfish species of typically Amazonian lineages in the Upper Rio Paraguay (Aspredinidae: Hoplomyzontinae and Trichomycteridae: Vandelliinae), with a biogeographic discussion

Abstract Two new species of particular biogeographic significance are described from the upper rio Paraguay basin, one of the genus Paracanthopoma (Trichomycteridae, Vandelliinae) and the other of the genus Ernstichthys (Aspredinidae, Hoplomyzontinae). The two species occur sympatrically in the Rio Taquarizinho, tributary of the Rio Taquari, in the upper Paraguay system. Paracanthopoma saci is distinguished from its only congener, P. parva, by a spatulate caudal peduncle; a minuscule premaxillary dentition (reduced to three delicate teeth); the supraorbital latero-sensory canals opening as two separate s6 pores; the caudal fin slightly convex or truncate with round edges; the skull roof entirely open, unossified; the origins of dorsal and anal fins approximately at same vertical; and the pelvic fin with three rays. Ernstichthys taquari is diagnosed among congeners by the narrow bony shields on dorsal and ventral series, not overlapping or contacting each other; by the presence of seven or eight serrations on the posterior margin of the pectoral spine; and by the pectoral-fin spine only slightly larger than subsequent soft rays. Both Paracanthopoma and Ernstichthys were previously unknown outside of the Greater Amazonian river systems (Amazon, Orinoco, Essequibo and smaller surrounding drainages). Their presence restricted to the Rio Taquari is unexpected and suggests a peculiar biogeographical history. Ancestral geographic distributions were reconstructed using S-DIVA and BBM methods in RASP. A majority of resulting hypotheses support that the two species reached the Paraguay from the Amazon. The alternative explanation accounts for their presence in the Paraguay by vicariant events. In no case, their presence in the Paraguay is an ancestral distribution with subsequent Amazonian dispersal. Though unusual, this pattern is also seen in a few other fish taxa, showing that the Rio Taquari is biogeographically hybrid, combining elements from both the Paraguay and Amazon drainages.

Two new catfish species of typically Amazonian lineages in the Upper Rio Paraguay (Aspredinidae: Hoplomyzontinae and Trichomycteridae: Vandelliinae), with a biogeographic discussion

Abstract Two new species of particular biogeographic significance are described from the upper rio Paraguay basin, one of the genus Paracanthopoma (Trichomycteridae, Vandelliinae) and the other of the genus Ernstichthys (Aspredinidae, Hoplomyzontinae). The two species occur sympatrically in the Rio Taquarizinho, tributary of the Rio Taquari, in the upper Paraguay system. Paracanthopoma saci is distinguished from its only congener, P. parva, by a spatulate caudal peduncle; a minuscule premaxillary dentition (reduced to three delicate teeth); the supraorbital latero-sensory canals opening as two separate s6 pores; the caudal fin slightly convex or truncate with round edges; the skull roof entirely open, unossified; the origins of dorsal and anal fins approximately at same vertical; and the pelvic fin with three rays. Ernstichthys taquari is diagnosed among congeners by the narrow bony shields on dorsal and ventral series, not overlapping or contacting each other; by the presence of seven or eight serrations on the posterior margin of the pectoral spine; and by the pectoral-fin spine only slightly larger than subsequent soft rays. Both Paracanthopoma and Ernstichthys were previously unknown outside of the Greater Amazonian river systems (Amazon, Orinoco, Essequibo and smaller surrounding drainages). Their presence restricted to the Rio Taquari is unexpected and suggests a peculiar biogeographical history. Ancestral geographic distributions were reconstructed using S-DIVA and BBM methods in RASP. A majority of resulting hypotheses support that the two species reached the Paraguay from the Amazon. The alternative explanation accounts for their presence in the Paraguay by vicariant events. In no case, their presence in the Paraguay is an ancestral distribution with subsequent Amazonian dispersal. Though unusual, this pattern is also seen in a few other fish taxa, showing that the Rio Taquari is biogeographically hybrid, combining elements from both the Paraguay and Amazon drainages.

Human impacts and the loss of Neotropical freshwater fish diversity

Neotropical Ichthyology promotes the Special Issue (SI) "Human impacts and the loss of Neotropical freshwater fish diversity" with the purpose of publishing relevant scientific articles on the current biodiversity crisis and the loss of Neotropical freshwater fishes in the Anthropocene. The SI is composed of 22 publications, being two review articles and 20 original articles. A total of 107 researchers contributed to these papers, involving 44 institutions based in Brazil and six other countries. Published articles investigated main anthropic activities and their impacts on fish diversity, with special focus on river regulation, mining, land use changes, aquaculture, and fisheries. Studies provided evidence about the loss of fish diversity in the Neotropics, including fish kill events, demographic changes, contamination, changes in assemblage structure, loss of taxonomic and functional diversity, besides the degradation of ecosystem functions and services, and the lack of effective protection and conservation. Studies were conducted in rivers, streams, lakes, and reservoirs from different Neotropical systems. The studies published in this SI represent a relevant sample of the current worrisome situation of freshwater fishes in the Neotropical region and call for urgent revision in environmental policies, management and conservation initiatives, and socioeconomic priorities.(AU)

A revista Neotropical Ichthyology lança o Volume Especial (SI) "Human impacts and the loss of Neotropical freshwater fish diversity" com o objetivo de publicar artigos científicos relevantes sobre a atual crise da biodiversidade e a perda de diversidade de peixes de água doce Neotropicais no Antropoceno. O SI é composto por 22 publicações, sendo dois artigos de revisão e 20 artigos originais. Um total de 107 pesquisadores contribuíram com esses artigos, envolvendo 44 instituições sediadas no Brasil e em seis outros países. Os artigos publicados investigaram as principais atividades antrópicas e seus impactos sobre a diversidade de peixes, com foco especial na regulação dos rios, mineração, mudanças no uso do solo, aquicultura e pesca. Os estudos forneceram evidências sobre a perda de diversidade de peixes na região Neotropical, incluindo eventos de mortandade, alterações demográficas, contaminação, mudanças na estrutura das assembleias, perda de diversidade taxonômica e funcional, além da degradação de funções e serviços ecossistêmicos, e falta de ações efetivas de proteção e conservação. Os estudos foram conduzidos em rios, riachos, lagos e reservatórios de diferentes sistemas Neotropicais. Os estudos publicados neste SI representam uma amostra relevante da atual situação dos peixes de água doce na região Neotropical, reforçando a necessidade de revisão das políticas ambientais, ações de manejo e conservação, e prioridades socioeconômicas.(AU)

Human impacts and the loss of Neotropical freshwater fish diversity

Neotropical Ichthyology promotes the Special Issue (SI) "Human impacts and the loss of Neotropical freshwater fish diversity" with the purpose of publishing relevant scientific articles on the current biodiversity crisis and the loss of Neotropical freshwater fishes in the Anthropocene. The SI is composed of 22 publications, being two review articles and 20 original articles. A total of 107 researchers contributed to these papers, involving 44 institutions based in Brazil and six other countries. Published articles investigated main anthropic activities and their impacts on fish diversity, with special focus on river regulation, mining, land use changes, aquaculture, and fisheries. Studies provided evidence about the loss of fish diversity in the Neotropics, including fish kill events, demographic changes, contamination, changes in assemblage structure, loss of taxonomic and functional diversity, besides the degradation of ecosystem functions and services, and the lack of effective protection and conservation. Studies were conducted in rivers, streams, lakes, and reservoirs from different Neotropical systems. The studies published in this SI represent a relevant sample of the current worrisome situation of freshwater fishes in the Neotropical region and call for urgent revision in environmental policies, management and conservation initiatives, and socioeconomic priorities.(AU)

A revista Neotropical Ichthyology lança o Volume Especial (SI) "Human impacts and the loss of Neotropical freshwater fish diversity" com o objetivo de publicar artigos científicos relevantes sobre a atual crise da biodiversidade e a perda de diversidade de peixes de água doce Neotropicais no Antropoceno. O SI é composto por 22 publicações, sendo dois artigos de revisão e 20 artigos originais. Um total de 107 pesquisadores contribuíram com esses artigos, envolvendo 44 instituições sediadas no Brasil e em seis outros países. Os artigos publicados investigaram as principais atividades antrópicas e seus impactos sobre a diversidade de peixes, com foco especial na regulação dos rios, mineração, mudanças no uso do solo, aquicultura e pesca. Os estudos forneceram evidências sobre a perda de diversidade de peixes na região Neotropical, incluindo eventos de mortandade, alterações demográficas, contaminação, mudanças na estrutura das assembleias, perda de diversidade taxonômica e funcional, além da degradação de funções e serviços ecossistêmicos, e falta de ações efetivas de proteção e conservação. Os estudos foram conduzidos em rios, riachos, lagos e reservatórios de diferentes sistemas Neotropicais. Os estudos publicados neste SI representam uma amostra relevante da atual situação dos peixes de água doce na região Neotropical, reforçando a necessidade de revisão das políticas ambientais, ações de manejo e conservação, e prioridades socioeconômicas.(AU)

The rediscovery of Pimelodella longipinnis (Borodin, 1927), an enigmatic Atlantic Rainforest catfish species from Southeastern Brazil (Siluriformes: Heptapteridae)

This article is a redescription of Pimelodella longipinnis, an enigmatic catfish previously known only from its holotype and with uncertain type locality. The species is redescribed based on recently collected materials from streams of the Mata Atlântica bioregion, in Santos municipality, São Paulo State, Brazil. Pimelodella longipinnis is assigned to a putatively monophyletic group, the Pimelodella leptosoma-group, diagnosed by the presence of a supraoccipital process not reaching the anterior nuchal plate, with a gap of ca. 20-25% of the supraoccipital process total length, and whose tip notably surpasses the midpoint of the complex vertebra in dorsal view. We also present a list of fish species described from a shipping sent to the American Museum of Natural History from the former Museu Paulista (now Museu de Zoologia da Universidade de São Paulo), of which P. longipinnis was part.(AU)

Insights on the influence of phylogenetic on the relative growth using Atherinella brasiliensis as a tool / Introspecções sobre a influência da filogenética no crescimento relativo usando Atherinella brasiliensis como ferramenta

The length–weight relationship (LWR) is an important tool for ichthyology. It is very useful to demonstrate the environmental influence on growth. In this study we estimate the LWR of the Atherinella brasiliensis in the shallow areas of the São Francisco River estuary and compare the growth of this specie in different environments of the Brazilian coast. Specimens of Brazilian silverside (A. brasiliensis, n = 3483), between 2.1 and 13.6 cm in length, were caught in the shallow areas of the São Francisco River estuary between May 2017 and April 2018. The length-weight ratio of the species was represented by the equation y = 0.0047x3.0913. Frequency distribution indicates that the species is present in the studied area in all its ontogenetic stages and apparently reproduces throughout the year with constant input of recruits into the population. Von Bertalanffy’s growth model and longevity were adjusted to reach asymptotic length (L∞) of 14.7 cm, growth coefficient (K) of 0.91 year-1 and longevity (A95) of 3.25 years. The analysis of variance revealed differences for the maximum total length. However, the differences found between the present study and data available in the literature appear to be caused by environmental and methodological differences.

A relação peso-comprimento (LWR) é uma ferramenta importante para a ictiologia, muito utilizada para demonstrar a influência ambiental no crescimento. Neste estudo estimamos o LWR de Atherinella brasiliensis em áreas rasas do estuário do rio São Francisco e comparamos o crescimento desta espécie em diferentes ambientes do litoral brasileiro. Espécimes do peixe-rei (A. brasiliensis, n = 3483), entre 2,1 e 13,6 cm de comprimento, foram capturados nas áreas rasas do estuário do rio São Francisco entre maio de 2017 e abril de 2018. A relação peso-comprimento das espécies foi representada por a equação y = 0,0047x3,0913. A distribuição de frequência indica que a espécie está presente na área estudada em todos os seus estágios ontogenéticos e aparentemente se reproduz ao longo do ano com entrada constante de recrutas na população. Os modelos de crescimento e longevidade de Von Bertalanffy foram ajustados para atingir comprimento assintótico (L∞) de 14,7 cm, coeficiente de crescimento (K) de 0,91 ano-1 e longevidade (A95) de 3,25 anos. A análise de variância revelou diferenças para o comprimento total máximo. No entanto, as diferenças encontradas entre o presente estudo e os dados disponíveis na literatura parecem ser causadas por diferenças ambientais e metodológicas.

Insights on the influence of phylogenetic on the relative growth using Atherinella brasiliensis as a tool / Introspecções sobre a influência da filogenética no crescimento relativo usando Atherinella brasiliensis como ferramenta

The length–weight relationship (LWR) is an important tool for ichthyology. It is very useful to demonstrate the environmental influence on growth. In this study we estimate the LWR of the Atherinella brasiliensis in the shallow areas of the São Francisco River estuary and compare the growth of this specie in different environments of the Brazilian coast. Specimens of Brazilian silverside (A. brasiliensis, n = 3483), between 2.1 and 13.6 cm in length, were caught in the shallow areas of the São Francisco River estuary between May 2017 and April 2018. The length-weight ratio of the species was represented by the equation y = 0.0047x3.0913. Frequency distribution indicates that the species is present in the studied area in all its ontogenetic stages and apparently reproduces throughout the year with constant input of recruits into the population. Von Bertalanffys growth model and longevity were adjusted to reach asymptotic length (L∞) of 14.7 cm, growth coefficient (K) of 0.91 year-1 and longevity (A95) of 3.25 years. The analysis of variance revealed differences for the maximum total length. However, the differences found between the present study and data available in the literature appear to be caused by environmental and methodological differences.(AU)

A relação peso-comprimento (LWR) é uma ferramenta importante para a ictiologia, muito utilizada para demonstrar a influência ambiental no crescimento. Neste estudo estimamos o LWR de Atherinella brasiliensis em áreas rasas do estuário do rio São Francisco e comparamos o crescimento desta espécie em diferentes ambientes do litoral brasileiro. Espécimes do peixe-rei (A. brasiliensis, n = 3483), entre 2,1 e 13,6 cm de comprimento, foram capturados nas áreas rasas do estuário do rio São Francisco entre maio de 2017 e abril de 2018. A relação peso-comprimento das espécies foi representada por a equação y = 0,0047x3,0913. A distribuição de frequência indica que a espécie está presente na área estudada em todos os seus estágios ontogenéticos e aparentemente se reproduz ao longo do ano com entrada constante de recrutas na população. Os modelos de crescimento e longevidade de Von Bertalanffy foram ajustados para atingir comprimento assintótico (L∞) de 14,7 cm, coeficiente de crescimento (K) de 0,91 ano-1 e longevidade (A95) de 3,25 anos. A análise de variância revelou diferenças para o comprimento total máximo. No entanto, as diferenças encontradas entre o presente estudo e os dados disponíveis na literatura parecem ser causadas por diferenças ambientais e metodológicas.(AU)

Pectoral-fin glands and delivery apparatus in the catfish genus Brachyrhamdia Myers, 1927 (Siluriformes: Heptapteridae)

The Siluriformes, popularly known as catfishes, are probably the vertebrate group with the highest diversity of venomous animals, even though only approximately a hundred venomous catfishes are reported to date. Venomous catfishes might present a delivery system apparatus, formed by an unbranched ray at the leading edge of pectoral and dorsal fins (spine), which can be stiffened and pungent, while venom glands can be present at the surface of such spines and/or the axillary region. This work investigated the presence, morphology and distribution of glands and pectoral-fin delivery apparatus in the heptapterid Brachyrhamdia genus. Pectoral-fin spine external morphology was compared across all valid species in the genus, histological sections of the pectoral-fin spine and axillary regions of B. heteropleura and B. marthae were produced, and dissections of the pectoral girdle region of the mentioned species were analyzed. The histological sections confirmed the presence of pectoral-fin glands at the surface of the pectoral-fin spine of Brachyrhamdia species, and cellular morphology indicates these glands are probably venomous. Also, we found a piriform gland at the axillary region, whose cell morphology is like the reported for other catfishes. However, we cannot currently confirm or deny axillary gland participation in the venom delivery apparatus. This work constitutes the first report of venom glands in Brachyrhamdia, and the first description of Heptapteridae axillary glands.(AU)

Two new catfish species of typically Amazonian lineages in the Upper Rio Paraguay (Aspredinidae: Hoplomyzontinae and Trichomycteridae: Vandelliinae), with a biogeographic discussion

Two new species of particular biogeographic significance are described from the upper rio Paraguay basin, one of the genus Paracanthopoma (Trichomycteridae, Vandelliinae) and the other of the genus Ernstichthys (Aspredinidae, Hoplomyzontinae). The two species occur sympatrically in the Rio Taquarizinho, tributary of the Rio Taquari, in the upper Paraguay system. Paracanthopoma saci is distinguished from its only congener, P. parva, by a spatulate caudal peduncle; a minuscule premaxillary dentition (reduced to three delicate teeth); the supraorbital latero-sensory canals opening as two separate s6 pores; the caudal fin slightly convex or truncate with round edges; the skull roof entirely open, unossified; the origins of dorsal and anal fins approximately at same vertical; and the pelvic fin with three rays. Ernstichthys taquari is diagnosed among congeners by the narrow bony shields on dorsal and ventral series, not overlapping or contacting each other; by the presence of seven or eight serrations on the posterior margin of the pectoral spine; and by the pectoral-fin spine only slightly larger than subsequent soft rays. Both Paracanthopoma and Ernstichthys were previously unknown outside of the Greater Amazonian river systems (Amazon, Orinoco, Essequibo and smaller surrounding drainages). Their presence restricted to the Rio Taquari is unexpected and suggests a peculiar biogeographical history. Ancestral geographic distributions were reconstructed using S-DIVA and BBM methods in RASP. A majority of resulting hypotheses support that the two species reached the Paraguay from the Amazon. The alternative explanation accounts for their presence in the Paraguay by vicariant events. In no case, their presence in the Paraguay is an ancestral distribution with subsequent Amazonian dispersal. Though unusual, this pattern is also seen in a few other fish taxa, showing that the Rio Taquari is biogeographically hybrid, combining elements from both the Paraguay and Amazon drainages.(AU)

Two new, remarkably colored species of the Neotropical catfish genus Cetopsorhamdia Eigenmann & Fisher, 1916 (Siluriformes, Heptapteridae) from Chapada dos Parecis, western Brazil, with an assessment of the morphological characters bearing on their phylogenetic relationships

Two new species of heptapterid catfish genus Cetopsorhamdia are described from close localities in western Brazil, at Chapada dos Parecis, an area with extremely high level of endemism. One species is from the upper Rio Madeira system, Rondônia State, and the other from the upper Rio Tapajós system, Mato Grosso State. The two species are diagnosed, among several other features, by their markedly distinctive color patterns, with the former having well-defined quadrangular marks in trunk flanks while the latter bearing irregular, vertical bars along the trunk. The monophyly of Cetopsorhamdia is discussed, with two putative synapomorphies being proposed to support the genus. Potentially informative morphological characters to resolve the internal relationships of the genus are presented and discussed. Despite the striking external differences between the two species herein described, they are found to likely form a clade.(AU)

Anatomia do tubo digestório da espécie Acestrorhynchus lacustres (Ostaryohisi, Characiformes) Lütken, 1875 do Rio de Ondas, Oeste da Bahia, Brasil} / Digestive tract anatomy of the species Acestrorhynchus lacustris (Ostaryohisi, Characiformes) Lütken, 1875 from Ondas River, Western Bahia, Brazil / Anatomía del tubo digestorial de la especie Acestrorhynchus lacustris (Ostaryohisi, Characiformes) Lütken, 1875 de Rio de Ondas, Oeste de Bahia, Brasil

O presente estudo visa descrever e mensurar o tubo digestório da espécie Acestrorhynchus lacustris. Foram utilizados 10 exemplares da espécie, coletados em diferentes trechos da bacia hidrográfica do rio de Ondas, localizada no Oeste do Estado da Bahia, na ecorregião aquática do rio São Francisco. Foram realizadas mensuração e pesagem dos peixes. A cavidade bucofaríngea e os órgãos digestórios pós-faríngeos: esôfago, estômago, cecos pilóricos e intestino foram analisados, descritos e mensurados. Para definição do tamanho dos órgãos da espécie, independente do tamanho do exemplar, foi calculado o comprimento relativo dos órgãos, exceto dos cecos pilóricos. A espécie A. lacustris apresenta boca terminal, fenda bucal e cavidade bucofaringea amplas, dentes cônicos e caninos; esôfago curto, musculoso e distensível; estômago alongado, musculoso, do tipo cecal, com formato de “Y”; sete a 15 cecos pilóricos que aparecem como evaginações no intestino; e intestino curto, musculoso e bastante espesso. Os dados obtidos demonstram que o tamanho dos órgãos que compõe o tubo digestório da espécie não está relacionado ao tamanho do exemplar. O estudo das características anatômicas do tubo digestório ampliou o conhecimento biológico e ecológico da espécie estudada, auxiliando na compreensão do desempenho desta espécie em ecossistemas naturais e na elaboração de propostas para a preservação ou manejo da espécie.

This study aims to describe and measure the digestive tract of the species Acestrorhynchus lacustris. Ten specimens of the species were used, captured in different parts of the river basin of the Ondas river, located west of the State of Bahia, in the aquatic ecoregion of the São Francisco river. Fish measurements and weighing were carried out. The oropharyngeal cavity and postpharyngeal digestive organs were analyzed, described and measured: esophagus, stomach, pyloric cecum and intestine. To define the size of the organs of the species, regardless of the size of the sample, the relative length of the organs, except the pyloric cecum, was calculated. The species A. lacustris has a terminal mouth, a wide oral cleft and oropharyngeal cavity, conical and canine teeth; short, muscular, and compliant esophagus; elongated, muscular stomach, cecal type, shaped like a "Y"; seven to fifteen pyloric cecum that appear as bowel movements; and intestine short, muscular and quite thick. The data obtained show that the size of the organs that make up the digestive tract of the species is not related to the size of the specimen. The study of the anatomical characteristics of the digestive tract expanded the biological and ecological knowledge of the studied species, helping to understand the performance of this species in natural ecosystems and in the elaboration of proposals for the preservation or management of the species.

Este estudio tiene como objetivo describir y medir el tubo digestivo de la especie Acestrorhynchus lacustris. Se utilizaron diez ejemplares de la especie, capturado en diferentes partes de la cuenca hidrográfica del río del Ondas, situado al oeste del Estado de Bahía, en la ecorregión acuática del río São Francisco. Se realizaron mediciones y pesaje de peces. Se analizaron, describieron y midieron la cavidad bucofaríngea y los órganos digestivos posfaríngeos: esófago, estómago, ciego pilórico e intestino. Para definir el tamaño de los órganos de la especie, independientemente del tamaño de la muestra, se calculó la longitud relativa de los órganos, excepto el ciego pilórico. La especie A. lacustris tiene boca terminal, hendidura bucal amplia y cavidad bucofaríngea, dientes cónicos y caninos; esófago corto, musculoso y distensible; estómago alargado, musculoso, tipo cecal, en forma de “Y”; de siete a quince ciegos pilóricos que aparecen como evacuaciones intestinales; e intestino corto, musculoso y bastante grueso. Los datos obtenidos demuestran que el tamaño de los órganos que componen el tubo digestivo de la especie no está relacionado con el tamaño del espécimen. El estudio de las características anatómicas del tubo digestivo amplió el conocimiento biológico y ecológico de las especies estudiadas, ayudando a comprender el desempeño de esta especie en ecosistemas naturales y en la elaboración de propuestas para la preservación o manejo de la especie.

Anatomia do tubo digestório da espécie Acestrorhynchus lacustres (Ostaryohisi, Characiformes) Lütken, 1875 do Rio de Ondas, Oeste da Bahia, Brasil} / Digestive tract anatomy of the species Acestrorhynchus lacustris (Ostaryohisi, Characiformes) Lütken, 1875 from Ondas River, Western Bahia, Brazil / Anatomía del tubo digestorial de la especie Acestrorhynchus lacustris (Ostaryohisi, Characiformes) Lütken, 1875 de Rio de Ondas, Oeste de Bahia, Brasil

O presente estudo visa descrever e mensurar o tubo digestório da espécie Acestrorhynchus lacustris. Foram utilizados 10 exemplares da espécie, coletados em diferentes trechos da bacia hidrográfica do rio de Ondas, localizada no Oeste do Estado da Bahia, na ecorregião aquática do rio São Francisco. Foram realizadas mensuração e pesagem dos peixes. A cavidade bucofaríngea e os órgãos digestórios pós-faríngeos: esôfago, estômago, cecos pilóricos e intestino foram analisados, descritos e mensurados. Para definição do tamanho dos órgãos da espécie, independente do tamanho do exemplar, foi calculado o comprimento relativo dos órgãos, exceto dos cecos pilóricos. A espécie A. lacustris apresenta boca terminal, fenda bucal e cavidade bucofaringea amplas, dentes cônicos e caninos; esôfago curto, musculoso e distensível; estômago alongado, musculoso, do tipo cecal, com formato de “Y”; sete a 15 cecos pilóricos que aparecem como evaginações no intestino; e intestino curto, musculoso e bastante espesso. Os dados obtidos demonstram que o tamanho dos órgãos que compõe o tubo digestório da espécie não está relacionado ao tamanho do exemplar. O estudo das características anatômicas do tubo digestório ampliou o conhecimento biológico e ecológico da espécie estudada, auxiliando na compreensão do desempenho desta espécie em ecossistemas naturais e na elaboração de propostas para a preservação ou manejo da espécie.(AU)

This study aims to describe and measure the digestive tract of the species Acestrorhynchus lacustris. Ten specimens of the species were used, captured in different parts of the river basin of the Ondas river, located west of the State of Bahia, in the aquatic ecoregion of the São Francisco river. Fish measurements and weighing were carried out. The oropharyngeal cavity and postpharyngeal digestive organs were analyzed, described and measured: esophagus, stomach, pyloric cecum and intestine. To define the size of the organs of the species, regardless of the size of the sample, the relative length of the organs, except the pyloric cecum, was calculated. The species A. lacustris has a terminal mouth, a wide oral cleft and oropharyngeal cavity, conical and canine teeth; short, muscular, and compliant esophagus; elongated, muscular stomach, cecal type, shaped like a "Y"; seven to fifteen pyloric cecum that appear as bowel movements; and intestine short, muscular and quite thick. The data obtained show that the size of the organs that make up the digestive tract of the species is not related to the size of the specimen. The study of the anatomical characteristics of the digestive tract expanded the biological and ecological knowledge of the studied species, helping to understand the performance of this species in natural ecosystems and in the elaboration of proposals for the preservation or management of the species.(AU)

Este estudio tiene como objetivo describir y medir el tubo digestivo de la especie Acestrorhynchus lacustris. Se utilizaron diez ejemplares de la especie, capturado en diferentes partes de la cuenca hidrográfica del río del Ondas, situado al oeste del Estado de Bahía, en la ecorregión acuática del río São Francisco. Se realizaron mediciones y pesaje de peces. Se analizaron, describieron y midieron la cavidad bucofaríngea y los órganos digestivos posfaríngeos: esófago, estómago, ciego pilórico e intestino. Para definir el tamaño de los órganos de la especie, independientemente del tamaño de la muestra, se calculó la longitud relativa de los órganos, excepto el ciego pilórico. La especie A. lacustris tiene boca terminal, hendidura bucal amplia y cavidad bucofaríngea, dientes cónicos y caninos; esófago corto, musculoso y distensible; estómago alargado, musculoso, tipo cecal, en forma de “Y”; de siete a quince ciegos pilóricos que aparecen como evacuaciones intestinales; e intestino corto, musculoso y bastante grueso. Los datos obtenidos demuestran que el tamaño de los órganos que componen el tubo digestivo de la especie no está relacionado con el tamaño del espécimen. El estudio de las características anatómicas del tubo digestivo amplió el conocimiento biológico y ecológico de las especies estudiadas, ayudando a comprender el desempeño de esta especie en ecosistemas naturales y en la elaboración de propuestas para la preservación o manejo de la especie.(AU)

Preface: How far has Neotropical Ichthyology progressed in twenty years?

Studies on the diversity, taxonomy, phylogeny, and biogeography of Neotropical Fishes have thrived over the twenty years that have elapsed since the first symposium on their phylogeny and classification in Porto Alegre, Brazil. Here, we review recent advances in the study of Neotropical fishes and assess the known diversity of freshwater species in that region. 6,255 valid freshwater species have been discovered in the Neotropics so far, and we estimate that over 9,000 species will be known when the inventory is complete. We also summarize the events of the second Symposium on Phylogeny and Classification of Neotropical Fishes that took place last year in Londrina, Brazil. Along with invited talks on the biodiversity of all major groups of Neotropical fishes, a series of presentations on the development of fish collections, and numerous contributed talks, the meeting included a special session to honor Dr. Richard Vari, who was one of the most prolific and beloved members of our community.(AU)

Estudos sobre diversidade, taxonomia, filogenia e biogeografia de peixes neotropicais prosperaram nos últimos vinte anos, desde o primeiro simpósio sobre filogenia e classificação em Porto Alegre, Brasil. Aqui, os novos avanços nos estudos de peixes neotropicais são discutidos e a diversidade conhecida reavaliada para espécies de água doce. Foram descobertas 6.255 espécies de peixes de água doce para na região Neotropical até o momento, e estimamos que haja mais de 9.000 espécies quando o inventário estiver completo. Nós resumimos as informações do segundo Simpósio sobre Filogenia e Classificação de Peixes Neotropicais ocorrido no ano passado em Londrina, Brasil. Além de apresentações de convidados sobre Biodiversidade dos grandes grupos de peixes Neotropicais, de uma série de apresentações sobre o estado da arte das coleções científicas, e de diversas outras apresentações, o simpósio incluíu uma sessão especial em homenagem ao Dr. Richard Vari, um dos membros mais prolíficos e amados da nossa comunidade.(AU)

Preface: How far has Neotropical Ichthyology progressed in twenty years?

Studies on the diversity, taxonomy, phylogeny, and biogeography of Neotropical Fishes have thrived over the twenty years that have elapsed since the first symposium on their phylogeny and classification in Porto Alegre, Brazil. Here, we review recent advances in the study of Neotropical fishes and assess the known diversity of freshwater species in that region. 6,255 valid freshwater species have been discovered in the Neotropics so far, and we estimate that over 9,000 species will be known when the inventory is complete. We also summarize the events of the second Symposium on Phylogeny and Classification of Neotropical Fishes that took place last year in Londrina, Brazil. Along with invited talks on the biodiversity of all major groups of Neotropical fishes, a series of presentations on the development of fish collections, and numerous contributed talks, the meeting included a special session to honor Dr. Richard Vari, who was one of the most prolific and beloved members of our community.(AU)

Estudos sobre diversidade, taxonomia, filogenia e biogeografia de peixes neotropicais prosperaram nos últimos vinte anos, desde o primeiro simpósio sobre filogenia e classificação em Porto Alegre, Brasil. Aqui, os novos avanços nos estudos de peixes neotropicais são discutidos e a diversidade conhecida reavaliada para espécies de água doce. Foram descobertas 6.255 espécies de peixes de água doce para na região Neotropical até o momento, e estimamos que haja mais de 9.000 espécies quando o inventário estiver completo. Nós resumimos as informações do segundo Simpósio sobre Filogenia e Classificação de Peixes Neotropicais ocorrido no ano passado em Londrina, Brasil. Além de apresentações de convidados sobre Biodiversidade dos grandes grupos de peixes Neotropicais, de uma série de apresentações sobre o estado da arte das coleções científicas, e de diversas outras apresentações, o simpósio incluíu uma sessão especial em homenagem ao Dr. Richard Vari, um dos membros mais prolíficos e amados da nossa comunidade.(AU)