The Complete Genome Sequences of three species from the killifish genus Kryptolebias (Rivulidae, Cyprinodontiformes).

The killifish genus Kryptolebias currently contains seven recognized species found in freshwater and mangrove microhabitats in South and Central America, the Caribbean, and Florida. Kryptolebias species have several unique features. Beyond its amphibious nature, two of the Kryptolebias species (K. marmoratus and K. hermaphroditus sensu Costa 2011) are the only known vertebrates capable of self-fertilization. Although reference genomes for self-fertilizing species are readily available, a complete understanding of the genomic basis leading to the transition in mating systems in the genus requires more genomic resources at a broader taxonomic level. Here, we present the complete genome sequences for three Kryptolebias species from Brazil: the endangered freshwater species Kryptolebias brasiliensis and Kryptolebias gracilis and the androdiecious but obligate outcrossing Kryptolebias ocellatus (sensu Costa 2011). The raw data and assembled genomes are available in GenBank.

Additive and non-additive epigenetic signatures of natural hybridization between fish species with different mating systems.

Hybridization is a major source of evolutionary innovation. In plants, epigenetic mechanisms can help to stabilize hybrid genomes and contribute to reproductive isolation, but the relationship between genetic and epigenetic changes in animal hybrids is unclear. We analysed the relationship between genetic background and methylation patterns in natural hybrids of two genetically divergent fish species with different mating systems, Kryptolebias hermaphroditus (self-fertilizing) and K. ocellatus (outcrossing). Co-existing parental species displayed highly distinct genetic (SNPs) and methylation patterns (37,000 differentially methylated cytosines). Hybrids had predominantly intermediate methylation patterns (88.5% of the sites) suggesting additive effects, as expected from hybridization between genetically distant species. The large number of differentially methylated cytosines between hybrids and parental species (n = 5,800) suggests that hybridization may play a role in increasing genetic and epigenetic variation. Although most of the observed epigenetic variation was additive and had a strong genetic component, we also found a small percentage of non-additive, potentially stochastic, methylation differences that might act as an evolutionary bet-hedging strategy and increase fitness under environmental instability.

Phylogenomics reveals extensive introgression and a case of mito-nuclear discordance in the killifish genus Kryptolebias.

Introgression is a widespread evolutionary process leading to phylogenetic inconsistencies among distinct parts of the genomes, particularly between mitochondrial and nuclear-based phylogenetic reconstructions (e.g., mito-nuclear discordances). Here, we used mtDNA and genome-wide nuclear sites to provide the first phylogenomic-based hypothesis on the evolutionary relationships within the killifish genus Kryptolebias. In addition, we tested for evidence of past introgression in the genus given the multiple reports of undergoing hybridization between its members. Our mtDNA phylogeny generally agreed with the relationships previously proposed for the genus. However, our reconstruction based on nuclear DNA revealed an unknown lineage - Kryptolebias sp. 'ESP' - as the sister group of the self-fertilizing mangrove killifishes, K. marmoratus and K. hermaphroditus. All individuals sequenced of Kryptolebias sp. 'ESP' had the same mtDNA haplotype commonly observed in K. hermaphroditus, demonstrating a clear case of mito-nuclear discordance. Our analysis further confirmed extensive history of introgression between Kryptolebias sp. 'ESP' and K. hermaphroditus. Population genomics analyses indicate no current gene flow between the two lineages, despite their current sympatry and history of introgression. We also confirmed introgression between other species pairs in the genus that have been recently reported to form hybrid zones. Overall, our study provides a phylogenomic reconstruction covering most of the Kryptolebias species, reveals a new lineage hidden in a case of mito-nuclear discordance, and provides evidence of multiple events of ancestral introgression in the genus. These findings underscore the importance of investigating different genomic information in a phylogenetic framework, particularly in taxa where introgression is common as in the sexually diverse mangrove killifishes.

Against the Odds: Hybrid Zones between Mangrove Killifish Species with Different Mating Systems.

Different mating systems are expected to affect the extent and direction of hybridization. Due to the different levels of sexual conflict, the weak inbreeder/strong outbreeder (WISO) hypothesis predicts that gametes from self-incompatible (SI) species should outcompete gametes from self-compatible (SC) ones. However, other factors such as timing of selfing and unilateral incompatibilities may also play a role on the direction of hybridization. In addition, differential mating opportunities provided by different mating systems are also expected to affect the direction of introgression in hybrid zones involving outcrossers and selfers. Here, we explored these hypotheses with a unique case of recent hybridization between two mangrove killifish species with different mating systems, Kryptolebias ocellatus (obligately outcrossing) and K. hermaphroditus (predominantly self-fertilizing) in two hybrid zones in southeast Brazil. Hybridization rates were relatively high (~20%), representing the first example of natural hybridization between species with different mating systems in vertebrates. All F1 individuals were sired by the selfing species. Backcrossing was small, but mostly asymmetrical with the SI parental species, suggesting pattern commonly observed in plant hybrid zones with different mating systems. Our findings shed light on how contrasting mating systems may affect the direction and extent of gene flow between sympatric species, ultimately affecting the evolution and maintenance of hybrid zones.

Filling the gaps: phylogeography of the self-fertilizing Kryptolebias species (Cyprinodontiformes: Rivulidae) along South American mangroves.

Mangrove killifishes of the genus Kryptolebias have been historically classified as rare because of their small size and cryptic nature. Major gaps in distribution knowledge across mangrove areas, particularly in South America, challenge the understanding of the taxonomic status, biogeographical patterns and genetic structuring of the lineages composing the self-fertilizing "Kryptolebias marmoratus species complex." In this study, the authors combined a literature survey, fieldwork and molecular data to fill major gaps of information about the distribution of mangrove killifishes across western Atlantic mangroves. They found that selfing mangrove killifishes are ubiquitously distributed across the Caribbean, Central and South American mangroves and report 14 new locations in South America, extending the range of both the "Central clade" and "Southern clade" lineages which overlap in the Amazon. Although substantial genetic differences were found between clades, the authors also found further genetic structuring within clades, with populations in Central America, north and northeast Brazil generally showing higher levels of genetic diversity compared to the clonal ones in southeast Brazil. The authors discuss the taxonomic status and update the geographical distribution of the Central and Southern clades, as well as potential dispersal routes and biogeographical barriers influencing the distribution of the selfing mangrove killifishes in the western Atlantic mangroves.

Integrative taxonomy identifies a new stingray species of the genus Hypanus Rafinesque, 1818 (Dasyatidae, Myliobatiformes), from the Tropical Southwestern Atlantic.

An integrative approach by the congruence of genetics, morphology and ecological niche modelling (ENM) was used to delimit a new species of Hypanus (Rafinesque, 1818), a recently resurrected genus of marine stingrays comprising eight species, five of which occur in the western Atlantic. The species with the widest distribution, Hypanus americanus (Hildebrand and Schroeder, 1928), from the northeastern coast of the United States to southeastern Brazil, was demonstrated to be paraphyletic based on protein-coding mitochondrial genome analyses. This data set also indicates that the genetic distance between the new species Hypanus berthalutzae sp. nov. and its three closely related species (H. americanus, H. longus and H. rudis) varies from 0.82% to 3.14%. In addition, Bayesian Analysis of Population Similarity using the mitochondrial gene mt-nd2 supports the separation of H. berthalutzae sp. nov. (southwestern Atlantic) from its sister species H. rudis (eastern Atlantic). Similarly, morphological and morphometric analyses corroborated four morphotypes within the H. americanus species group and indicated the ventral caudal fold height and length and interspiracular and interorbital lengths as useful measurements to distinguish among them. Claspers of adult males also exhibit morphological differences among species. The ENM agreed with molecular and morphological analyses and delimits the distribution of H. berthalutzae sp. nov. to shallow areas close to shore along the Brazilian coast, from the mouth of the Amazon River to São Paulo State, including the northeastern oceanic islands, suggesting that the great outflow of fresh water and sediments and the Mid-Atlantic Ridge might act as barriers. The integration of these data to describe a new species provides information relevant to their conservation status, because all species of the H. americanus species group are under the "data-deficient" status.

More than meets the eye: syntopic and morphologically similar mangrove killifish species show different mating systems and patterns of genetic structure along the Brazilian coast.

Different mating systems can strongly affect the extent of genetic diversity and population structure among species. Given the increased effects of genetic drift on reduced population size, theory predicts that species undergoing self-fertilisation should have greater population structure than outcrossed species; however, demographic dynamics may affect this scenario. The mangrove killifish clade is composed of the two only known examples of self-fertilising species among vertebrates (Kryptolebias marmoratus and Kryptolebias hermaphroditus). A third species in this clade, Kryptolebias ocellatus, inhabits mangrove forests in southeast Brazil; however, its mating system and patterns of genetic structure have been rarely explored. Here, we examined the genetic structure and phylogeographic patterns of K. ocellatus along its distribution, using mitochondrial DNA and microsatellites to compare its patterns of genetic structure with the predominantly selfing and often-syntopic, K. hermaphroditus. Our results indicate that K. ocellatus reproduces mainly by outcrossing, with no current evidence of selfing, despite being an androdioecious species. Our results also reveal a stronger population subdivision in K. ocellatus compared to K. hermaphroditus, contrary to the theoretical predictions based on reproductive biology of the two species. Our findings indicate that, although morphologically similar, K. ocellatus and K. hermaphroditus had remarkably different evolutionary histories when colonising the same mangrove areas in southeastern Brazil, with other factors (e.g., time of colonisation, dispersal/establishment capacity) having more profound effects on the current population structuring of those species than differences in mating systems.

A biogeographic framework of octopod species diversification: the role of the Isthmus of Panama.

The uplift of the Isthmus of Panama (IP) created a land bridge between Central and South America and caused the separation of the Western Atlantic and Eastern Pacific oceans, resulting in profound changes in the environmental and oceanographic conditions. To evaluate how these changes have influenced speciation processes in octopods, fragments of two mitochondrial (Cytochrome oxidase subunit I, COI and 16S rDNA) and two nuclear (Rhodopsin and Elongation Factor-1α, EF-1α) genes were amplified from samples from the Atlantic and Pacific oceans. One biogeographical and four fossil calibration priors were used within a relaxed Bayesian phylogenetic analysis framework to estimate divergence times among cladogenic events. Reconstruction of the ancestral states in phylogenies was used to infer historical biogeography of the lineages and species dispersal routes. The results revealed three well-supported clades of transisthmian octopus sister species pair/complex (TSSP/TSSC) and two additional clades showing a low probability of species diversification, having been influenced by the IP. Divergence times estimated in the present study revealed that octopod TSSP/TSSC from the Atlantic and Pacific diverged between the Middle Miocene and Early Pliocene (mean range = 5-18 Ma). Given that oceanographic changes caused by the uplift of the IP were so strong as to affect the global climate, we suggest that octopod TSSP/TSSC diverged because of these physical and environmental barriers, even before the complete uplift of the IP 3 Ma, proposed by the Late Pliocene model. The results obtained in this phylogenetic reconstruction also indicate that the octopus species pairs in each ocean share a recent common ancestor from the Pacific Ocean.

Freshwater fish richness baseline from the São Francisco Interbasin Water Transfer Project in the Brazilian Semiarid

Among Neotropical freshwater ecoregions, the Mid-Northeastern Caatinga (MNCE) is a fish knowledge gap. Its temporary drainages are receptors of the São Francisco interbasin water transfer project (SFR-IWT) in the Brazilian semiarid. We provide a comprehensive baseline of fish richness of the five SFR-IWT basins. Species richness, shared, endemic, threatened and non-native species were obtained using sampling, ichthyologic collections, literature and online repositories (306 localities). In total 121, species were recorded, 111 of them native, and 16 (14.41%) listed for all basins. Higher richness of native species (78, 70.27%) was recorded in the São Francisco lower-middle stretch (SFRE), including 23 endemic, 61 (54.95%) in MNCE basins (13 endemic), and 28 (25.23%) shared between both ecoregions. In the MNCE, 50 species were recorded in Jaguaribe (JAG), 39 in Piranhas-Açu, 36 in Paraíba do Norte, and 32 in Apodi-Mossoró (APO). The number of species shared between the SFRE and each receptor basin varied from 24 (23.08%, JAG) to 20 (22.22%, APO). JAG contains 81.97% of the receptor basins' species. Its higher richness and endemism deserve special attention regarding the ongoing hydrological changes. This study will help detect possible modifications in the ichthyofauna of the main MNCE drainages.(AU)

Dentre as ecorregiões dulcícolas neotropicais, a Nordeste Médio-Oriental (MNCE) é uma lacuna de conhecimento sobre peixes. Suas drenagens temporárias são receptoras do projeto de transposição do São Francisco (SFR-IWT) no semiárido brasileiro. Fornecemos uma linha de base abrangente da riqueza de peixes das cinco bacias do SFR-IWT. Riqueza de espécies, espécies compartilhadas, endêmicas, ameaçadas e não-nativas foram obtidas através de amostragem, coleções ictiológicas, literatura e repositórios online (306 localidades). No total, foram registradas 121 espécies, 111 nativas e 16 (14,41%) listadas para todas as bacias. A maior riqueza de espécies nativas (78, 70,27%) foi registrada no trecho sub-médio do São Francisco (SFRE), incluindo 23 endêmicas e 61 (54,95%) nas bacias da MNCE (13 endêmicas), e 28 (25,23 %) compartilhadas entre ambas ecorregiões. Na MNCE, foram registradas 50 espécies na Jaguaribe (JAG), 39 na Piranhas-Açu, 36 na Paraíba do Norte e 32 na Apodi-Mossoró (APO). O número de espécies compartilhadas entre SFRE e cada bacia receptora variou de 24 (23,08%, JAG) a 20 (22,22%, APO). JAG contém 81,97% das espécies das bacias receptoras. Sua maior riqueza e endemismo merecem atenção especial em relação às mudanças hidrológicas em curso. Este estudo ajudará a detectar possíveis modificações na ictiofauna das principais drenagens da MNCE.(AU)

Local parasite pressures and host genotype modulate epigenetic diversity in a mixed-mating fish.

Parasite-mediated selection is one of the main drivers of genetic variation in natural populations. The persistence of long-term self-fertilization, however, challenges the notion that low genetic variation and inbreeding compromise the host's ability to respond to pathogens. DNA methylation represents a potential mechanism for generating additional adaptive variation under low genetic diversity. We compared genetic diversity (microsatellites and AFLPs), variation in DNA methylation (MS-AFLPs), and parasite loads in three populations of Kryptolebias hermaphroditus, a predomintanly self-fertilizing fish, to analyze the potential adaptive value of DNA methylation in relation to genetic diversity and parasite loads. We found strong genetic population structuring, as well as differences in parasite loads and methylation levels among sampling sites and selfing lineages. Globally, the interaction between parasites and inbreeding with selfing lineages influenced DNA methylation, but parasites seemed more important in determining methylation levels at the local scale.

Distribution, morphological notes and conservation status of the psammophilus Microcambeva catfishes (Siluriformes: Trichomycteridae).

Sarcoglanidinae and Glanapteryginae catfishes are among the most unusual elements of the Neotropical freshwater fish fauna. Microcambeva ribeirae, M. barbata and M. draco are miniaturized Sarcoglanidinae known to occur in sandy microhabitats in drainages of the Brazilian Atlantic Forest. Due to their specific habitats, specimens of Microcambeva are rare in fish collections, and new records are considered noteworthy to warrant report. Recently, specimens of this genus were newly found in the Rio Doce basin in Minas Gerais and Espírito Santo States. Such new records expand the known geographic distribution of Microcambeva. Further records of Microcambeva for Rio Peruípe in south Bahia State are also reported. Comments on the distribution of Microcambeva species along the Atlantic Forest coastal basins and suggestions on its conservation status are also offered.

Unravelling the foraging behavior of the southern stingray, Hypanus americanus (Myliobatiformes: Dasyatidae) in a Southwestern Atlantic MPA

Previous study suggested that the southern stingray (Hypanus americanus) displays a marked ontogenetic shift in its habitat use in the Fernando de Noronha Archipelago (FNA), an attractive touristic spot in Brazil, that could be associated with changes in its feeding habits and foraging strategies. Here, we conducted underwater visual surveys (~100 h a 3 years' study) at this site to describe the foraging behavior of the same species in details and to assess diel patterns in activity. We observed that H. americanus is capable of several complex and highly plastic behaviors (we described more than 21 of them) while foraging. The foraging events' timing appears to be related to the size (as well as sex) of the stingrays, environment and depth. In addition, our results support a segregation of habitat mediated by the size and sex of the stingrays, but it is able to modulate its foraging repertoire based mainly on environmental stimulus. Finally, we found that H. americanus forage intermittently throughout the day and tidal cycle, yet are less active during non-crepuscular periods and at flood and ebb tides. These results, coupled with the fact that the species uses both reef and beach environments, should be considered by decision makers in management plans.(AU)

Um estudo anterior sugeriu que a raia-prego (Hypanus americanus) apresenta uma marcante mudança ontogenética no seu uso de hábitat no Arquipélago de Fernando de Noronha (FNA), local turístico atraente no Brasil, que pode ser associado a mudanças em seus hábitos alimentares e estratégias de forrageamento. Aqui, nós conduzimos amostragens visuais subaquáticas (~100 h em 3 anos de estudo) nesse local para descrever o comportamento de forrageamento dessa mesma espécie em detalhes e acessar seu padrão de atividade diário. Nós observamos que H. americanus tem capacidade para comportamentos complexos e altamente plásticos (nós descrevemos mais de 21 deles) enquanto forrageia. O tempo dos eventos de forrageamento parece estar relacionado com o tamanho (e também sexo) das raias, ambiente e profundidade. Além disso, nossos resultados apoiam a ideia de uma segregação de hábitat mediada pelo tamanho e sexo das arraias, mas que ela é capaz de modular seu repertório de forrageio baseado principalmente em estímulos ambientais. Finalmente, nós descobrimos que H. americanus forrageia de forma intermitente ao longo do dia e ciclos de marés, mas é menos ativa durante os períodos não-crepusculares e nas enchentes e vazantes das marés. Esses resultados, somado ao fato que a espécie utiliza tanto ambientes recifais quanto praianos, devem ser considerados pelos tomadores de decisão em planos de manejo.(AU)

Updated checklist and DNA barcode-based species delimitations reveal taxonomic uncertainties among freshwater fishes from the mid-north-eastern Caatinga ecoregion, north-eastern Brazil.

The mid-north-eastern Caatinga is a semiarid freshwater ecoregion in North-eastern Brazil that is dominated by temporary rivers and is currently classified as one of the least ichthyologically-known ecoregions in the world. The present study aimed to provide an updated checklist of mid-north-eastern Caatinga ecoregion (MNCE) freshwater fish species and evaluate their taxonomic identity using morphology, DNA barcoding and multiple species delimitation approaches. After reviewing published studies and ichthyological collections, 119 species were identified. Among these were 94 putatively valid native and 14 non-native species, five undescribed native species, four new records for the MNCE, 11 potential cases of misidentification and 14 species listed as inquirenda. Additionally, 252 individuals from 49 species were barcoded, revealing three potential taxonomic synonyms. The combined molecular approaches estimated a total of 91 native species, although a finalized species list for the MNCE awaits additional taxonomic revisions and field surveys. This study provides the most up-to-date species checklist for the MNCE and a molecular reference database for identifying MNCE fishes with DNA barcodes. Results highlight the need to integrate traditional taxonomy with molecular approaches to correctly identify species, especially in taxonomically problematic ecoregions such as the MNCE.

Redescription of Hyphessobrycon itaparicensis, a senior synonym of H. sergipanus (Characiformes: Characidae)

Hyphessobrycon itaparicensis was originally described from a small stream in the Itaparica coastal island, Bahia State, Brazil, and has been sampled in several coastal rivers draining Bahia and Sergipe States. Broad examination of type material and recently collected specimens resulted in the redescription provided herein. The presence of one humeral blotch, absence of pseudotympanum, and conservation aspects of H. itaparicensis are briefly discussed. Data obtained from the original description, paratypes and topotypes of H. sergipanus showed broad overlap with H. itaparicensis and absence of morphological diagnostic features supporting the recognition of H. sergipanus as a valid species. Thus, H. sergipanus is considered as junior synonym of H. itaparicensis. We emphasize the need of examining large population samples and type material of similar congeners to avoid improper propositions of new specific names.(AU)

Hyphessobrycon itaparicensis foi descrita de um pequeno riacho na Ilha de Itaparica, Estado da Bahia, Brasil, e tem sido amostrada em outros rios costeiros nos estados da Bahia e Sergipe. Um amplo exame do material tipo e exemplares recentemente coletados resultou na redescrição aqui apresentada. A presença de uma mancha umeral, a ausência de pseudotímpano e aspectos da conservação de H. itaparicensis são brevemente discutidos. Dados obtidos da descrição original, de parátipos e topótipos de H. sergipanus revelaram ampla sobreposição com H. itaparicensis e ausência de características morfológicas diagnósticas que sustentem o reconhecimento de H. sergipanus como espécie válida. Assim, H. sergipanus é considerada sinônimo júnior de H. itaparicensis. Nós enfatizamos a necessidade de examinar grandes amostras das populações e do material tipo de congêneres semelhantes para evitar a proposição indevida de nomes novos de espécies.(AU)

Headwater Capture Evidenced by Paleo-Rivers Reconstruction and Population Genetic Structure of the Armored Catfish (Pareiorhaphis garbei) in the Serra do Mar Mountains of Southeastern Brazil.

Paleo-drainage connections and headwater stream-captures are two main historical processes shaping the distribution of strictly freshwater fishes. Recently, bathymetric-based methods of paleo-drainage reconstruction have opened new possibilities to investigate how these processes have shaped the genetic structure of freshwater organisms. In this context, the present study used paleo-drainage reconstructions and single-locus cluster delimitation analyses to examine genetic structure on the whole distribution of Pareiorhaphis garbei, a 'near threatened' armored catfish from the Fluminense freshwater ecoregion in Southeastern Brazil. Sequences of two mitochondrial genes (cytochrome b and cytochrome c oxidase subunit 1) were obtained from five sampling sites in four coastal drainages: Macaé (KAE), São João (SJO), Guapi-Macacu [sub-basins Guapiaçu (GAC) and Guapimirim (GMI)], and Santo Aleixo (SAL). Pronounced genetic structure was found, involving 10 haplotypes for cytB and 6 for coi, with no haplotypes shared between localities. Coalescent-based delineation methods as well as distance-based methods revealed genetic clusters corresponding to each sample site. Paleo-drainage reconstructions showed two putative paleo-rivers: an eastern one connecting KAE and SJO; and a western one merging in the Guanabara Bay (GAC, GMI, and SAL). A disagreement was uncovered between the inferred past riverine connections and current population genetic structure. Although KAE and SJO belong to the same paleo-river, the latter is more closely related to specimens from the Guanabara paleo-river. This discordance between paleo-drainage connections and phylogenetic structure may indicate an ancient stream-capture event in headwaters of this region. Furthermore, all analyses showed high divergence between KAE and the other lineages, suggesting at least one cryptic species in the latter, and that the nominal species should be restricted to the Macaé river basin, its type locality. In this drainage, impacts such as the invasive species and habitat loss can be especially threatening for such species with a narrow range. Our results also suggest that freshwater fishes from headwaters in the Serra do Mar mountains might have different biogeographical patterns than those from the lowlands, indicating a complex and dynamic climatic and geomorphological history.

A new species of armored catfish Parotocinclus (Siluriformes: Loricariidae) from the rio Parnaíba basin, northeastern, Brazil

Recent taxonomic studies indicated the presence of several undescribed species in the rio Parnaíba basin. Among those, a new species of Parotocinclus endemic of this drainage is herein described. It differs from most of its congeners, including the sympatric P. haroldoi and P. cearensis, by a vestigial or rudimentary adipose fin (vs. conspicuous adipose fin). This character is also present in P. bidentatus and P. muriaensis (both from the rio Paraíba do Sul basin, southeastern Brazil), P. spilurus (rio Jaguaribe basin, northeastern Brazil), P. seridoensis (rio Piranhas-Açu basin, northeastern Brazil), P. halbothi (rios Trombetas and Marowijne basins, northern Brazil and Suriname) and P. dani (from rio Tapajós in Mato Grosso State, Brazil). The new species differs from these latter species mainly by the abdomen extensively covered by broad dermal plates. It also differs from P. haroldoi and P. cearensis by light bands between the snout tip and the nostrils.(AU)

Estudos taxonômicos recentes indicaram a presença de várias espécies não descritas na bacia do rio Parnaíba. Dentre estas, uma nova espécie de Parotocinclus endêmica desta drenagem é aqui descrita. Ela difere da maioria dos seus congêneres, incluindo as simpátricas P. haroldoi e P. cearensis, por apresentar nadadeira adiposa vestigial ou rudimentar (vs. nadadeira adiposa desenvolvida). Este caráter também está presente em P. bidentatus e P. muriaensis (ambos do rio Paraíba do Sul, sudeste do Brasil), P. spilurus (bacia do rio Jaguaribe, nordeste do Brasil), P. seridoensis (bacia do rio Piranhas-Açu, nordeste do Brasil), P. halbothi (bacias dos rios Trombetas e Marowijne, norte do Brasil e no Suriname) e P. dani (do rio Tapajós no Estado do Mato Grosso, Brasil). A nova espécie difere destas principalmente pelo abdômen extensivamente coberto por placas dérmicas largas. Também difere de P. haroldoi e P. cearensis pela presença de faixas claras entre a ponta do focinho e as narinas.(AU)

Population Structure of the Rockpool Blenny Entomacrodus vomerinus Shows Source-Sink Dynamics among Ecoregions in the Tropical Southwestern Atlantic.

The Tropical Southwestern Atlantic is characterized by prominent ecosystems with large-scale oceanographic complexity. Yet, the evolutionary processes underlying genetic differentiation and connectivity in this region remain largely unknown. Entomacrodus vomerinus (Valenciennes, 1836) is a demersal fish with planktonic larvae endemic to this marine province, inhabiting shallow tidal pools in continental and oceanic reef environments. We evaluated the population structure, genetic diversity and gene flow of E. vomerinus using mitochondrial data (CYTB and COI) and nuclear (rhodopsin, RHO) DNA sequences. We sampled a total of 85 individuals, comprising 46 from three oceanic archipelagos with varying distance from the coast (São Pedro and São Paulo-SS, Fernando de Noronha-FE and Rocas Atoll-RA) and 39 from two localities in northeastern Brazilian coast (Rio Grande do Norte-RN and Bahia-BA). Multilocus analysis revealed the presence of three Evolutionarily Significant Units-ESUs (SS, FE+RA, and RN+BA), which are in accordance with distinct marine ecoregions. Coalescent analyses showed that the central ESU has a larger effective population size than the other two, suggesting strong asymmetries in the genetic diversity across the species range. Moreover, they showed that gene flow is highly asymmetric, suggesting a source-sink dynamics from the central ESU into the remaining ones, in agreement with oceanic currents. Together, these results provide insights in the evolutionary mechanisms facilitating diversification in this marine province.

First record of a male of Kryptolebias hermaphroditus Costa, 2011 (Cyprinodontiformes: Cynolebiidae)

During an ichthyological survey in September 2015 at the Ceará-Mirim River estuary, Rio Grande do Norte State, northeastern Brazil, we collected a male of Kryptolebias hermaphroditus , a cynolebiid species that had been previously described as containing exclusively self-fertilizing hermaphrodites. This is the first record of a male in this species, over 140 years after the discovery of the mangrove rivulid species from Brazil. Our discovery reinforces the need for more studies in K. hermaphroditus , as well as the potential of this species as a model for evolutionary studies due to its unique mating system.(AU)

Durante uma amostragem ictiológica em setembro de 2015 no estuário do rio Ceará-Mirim, Estado do Rio Grande do Norte, Nordeste do Brasil, nós coletamos um macho de Kryptolebias hermaphroditus , uma espécie de rivulídeo que foi descrita como contendo apenas hermafroditas auto-fertilizantes. Este é o primeiro registro de um macho dessa espécie, mais de 140 anos depois da descoberta das espécies de rivulídeos de manguezais do Brasil. Nossa descoberta reforça a necessidade de mais estudos em K . hermaphroditus , assim como, o potencial desta espécie como um modelo para estudos evolutivos devido ao seu sistema reprodutivo único.(AU)

Redescription of the endangered hypoptopomatine catfish Parotocinclus spilurus (Fowler, 1941) (Siluriformes: Loricariidae) from the upper rio Jaguaribe basin, northeastern Brazil

Abstract Parotocinclus spilurus (Fowler) was originally described as a species of Plecostomus based on six specimens collected in the rio Salgado, Icó Municipality, Ceará State, northeastern Brazil. Because the original description of P. spilurus is brief and uninformative, a detailed redescription of this endangered species based on the type series and on freshly collected topotypes was made. Data on osteology, intraspecific variation, sexual dimorphism and color pattern in life are presented for the first time, aiming at providing the necessary characters to differentiate the species from its congeners, as well as providing data on the distribution, habitat and conservation.

Resumo Parotocinclus spilurus (Fowler)foi descrita originalmente como uma espécie do gênero Plecostomus combase em seis espécimes coletados no rio Salgado, Município de Icó, Estado do Ceará. Devido à descrição original de P. spilurus ser breve e pouco informativa, uma redescrição detalhada desta espécieameaçada combase na série tipo e em topótipos recentemente coletados foi feita. Dados de osteologia, variação ontogenética, dimorfismo sexual e padrão de coloração em vida são apresentados pela primeira vez, com o objetivo de fornecer caracteres necessários para distinguir a espécie das suas demais congêneres, assim como fornecer dados de distribuição, habitat e conservação.

Ituglanis agreste, a new catfish from the rio de contas basin, northeastern Brazil (siluriformes: trichomycteridae)

Ituglanis agreste, a new species of catfish, is described from a tributary stream of the rio Gongogi drainage, rio de Contas basin, Bahia State, northeastern Brazil, from a transition area between the Atlantic Rain Forest and the semi-arid Caatinga savanna. This species is distinguished from its congeners by the following characters: elongate interopercle plate with high number of odontodes (26-30), high number of ribs (5-6), fewer vertebrae (36), number of branchiostegal rays (7), number of pectoral-fin rays (i,6) and absence of s1 pore. Comparisons with other Ituglanis species and putative plesiomorphic characters are presented. Some comments about conservation of Ituglanis species from northeastern Brazil are also made.

Ituglanis agreste, espécie nova, é descrita de um tributário da drenagem do rio Gongogi, bacia do rio de Contas, Bahia, nordeste do Brasil, de uma área de transição entre dois biomas, a Caatinga e a Mata Atlântica. Esta espécie distingue-se de todas as demais espécies do gênero pelas seguintes características: placa interopercular alongada com elevado número de odontódeos (26-30), número elevado de costelas (5-6), número reduzido de vértebras (36), número de raios branquiostégios (7), número de raios da nadadeira peitoral (i,6), e ausência do poro s1. Comparações com outras espécies de Ituglanis e a presença de supostos caracteres plesiomórficos são apresentados. Alguns comentários sobre conservação das espécies de Ituglanis do nordeste do Brasil também são feitos.