Chromatic polymorphism in Trichomycterus jacupiranga from eastern Brazilian Coastal basins (Siluriformes: Trichomycteridae).

Trichomycterinae catfishes often have high intraspecific variability in colour patterns that may be associated with ontogenetic changes or habitat preferences. In species of the eastern South American genus Trichomycterus s.s., some cases of chromatic polymorphism have been reported but colour pattern is still considered an important tool for species identification. Herein, we first describe chromatic polymorphism in the geographically widespread T. jacupiranga, comparing populations from Tijuca National Park and Ribeira do Iguape basin, identifying four syntopic colour morphs. In addition, we performed a phylogenetic analysis using partial sequences of the mitochondrial gene 12Ss gene for 16 individuals of T. jacupiranga, with a maximum of 0.2% of genetic distance, corroborating T. jacupiranga as a single widespread species. Finally, based on our results and field observations, we concluded that it is not possible at the present to associate chromatic polymorphism in T. jacupiranga with habitat preferences, since specimens with different colouration in variable ontogenetic stages were found at the same microhabitats.

Two new miniature translucent catfish species of the rare genus Tridens (Siluriformes: Trichomycteridae) from the Madeira River basin, northern Brazil.

Two new miniature species of the trichomycterid genus Tridens are described from the Madeira River drainage, Acre and Rondônia States, Brazil. Until this work, Tridens was a monotypic genus composed solely of Tridens melanops, from the Putumayo/Içá River drainage, upper Amazonas River basin. Tridens vitreus sp.n. is known from upper and middle Madeira River drainage and differs from all other congeners by the lack of pelvic fins and girdle and by vertebra and dorsal-fin ray counts. Tridens chicomendesi sp.n. is known from Abunã River, middle Madeira River drainage and is distinguished from all other congeners by the number of vertebrae, dorsal-fin ray count and anal-fin base colouration pattern. Tr. chicomendesi sp.n. is further distinguished from T. vitreus by a combination of character states regarding the position of urogenital opening, dorsal-fin position, anal-fin position, maxillary barbel length, number of premaxillary teeth, number of dorsal-fin rays, number of anal-fin rays, number of lateral-line system pores, frontal bone anatomy, degree of ossification of maxilla, anatomy of quadrate-hyomandibular joint, size of posterodorsal process of hyomandibula, length of opercular patch of odontodes, number of interopercular odontodes, proportion of upper hypural plate cartilage relative to its area ; by the absence of a proximal, distal and ventral cartilages on ventral hypohyal; by the absence of a lateral process on basibranchial 4; by the presence of a cartilage block on the lateral process of autopalatine, the presence of a well-developed ossification on proximal margin of ventral hypohyal, the presence of hypobranchial foramen; and by the presence of an anterior cartilaginous joint between quadrate and base of posterodorsal process of hyomandibula. This work represents the first species description for the subfamily Tridentinae in more than 30 years and for the genus Tridens since its original description in 1889.

Integrative Taxonomy, Distribution and Ontogenetic Colouration Change in Neotropical Mountain Catfishes of the Trichomycterus nigroauratus Group (Siluriformes: Trichomycteridae).

Catfishes of the genus Trichomycterus comprise the most diverse fish group in mountain river basins crossing the Atlantic Forest of south-eastern Brazil, with a great concentration of species in the Rio Paraíba do Sul basin. The present study is directed to the T. nigroauratus group, endemic to the Rio Paraíba do Sul basin, comprising species commonly found associated with bottom leaf litter. Field studies revealed two sympatric, distinct colour morphs, one comprising small specimens with a black longitudinal stripe over a pale brown ground colour on the flank and another comprising a single larger specimen with small dark browns spots scattered over a pale-yellow ground colour. These specimens were found in the upper Rio Paraitinga drainage, an area disjunct from the area inhabited by the other species of the group. We performed coalescent single-locus analyses for species delimitation using a cytochrome b fragment (1088 bp) for specimens from eight localities, including sequences taken from specimens exhibiting different colouration morphs and topotypes of all the three nominal species of the T. nigroauratus group. The analyses supported the two colouration morphs as belonging to a single species that is herein described. It is distinguished from other congeners by its unique colour pattern, dorsal and anal fins fin more posteriorly placed, and by the morphology of the opercle, metapterygoid and pelvic bone. The Maximum Likelihood analysis indicated the new species as sister to a clade containing all other congeners of the group, which is corroborated by osteological data. The occurrence of different lineages in neighbouring areas of the upper Rio Paraíba do Sul basin is interpreted as a possible vestige of a past complex paleogeographical scenario during the Cenozoic. The present record of striking ontogenetic colouration change, revealed only after checking DNA sequences of individuals exhibiting different colouration phenotypes, again highlights the importance of combining morphological and molecular data in taxonomical studies.

A new catfish species of the genus Cambeva (Siluriformes: Trichomycteridae) from the Rio Iguaçu drainage, southern Brazil, with a remarkable unique colour pattern.

Cambeva melanoptera sp. nov. is described from stream tributaries of the Rio Iratim, Rio Iguaçu drainage, southern Brazil. This new species is remarkable with a colour pattern not found elsewhere among trichomycterid catfishes, consisting of a broad distal black zone in all unpaired and pectoral fins, strongly contrasting with a pale-yellow proximal zone. C. melanoptera also differs from all other trichomycterids from eastern South America by the presence of the nasal barbel about thrice longer than the maxillary and rictal barbels. Due to the presence of a similar bicolour caudal fin, the new species is tentatively considered closely related to Cambeva castroi and Cambeva diabola, as well as more closely related to C. castroi than to C. diabola, with the first two species sharing the presence of a curved lateral process of the parurohyal and a trapezoidal projection on the lateral margin of the lateral ethmoid. The great morphological diversity found in Cambeva species endemic to the Rio Iguaçu drainage, including numerous exclusive characteristics not occurring in congeners and in any other species of closely related trichomycterine genera, indicates the need for more studies focusing on possible causal factors responsible for such unique diversification pattern.

Phylogenetic position of Trichomycterus astromycterus (Siluriformes: Trichomycteridae), an enigmatic trichomycterid from eastern Brazil, inferred from molecular data.

Recently in this journal, a new trichomycterine from eastern Brazil, Trichomycterus astromycterus, was described and considered possibly related to the Chilean Bullockia maldonadoi due to morphological similarities. Subsequently, osteological data supported T. astromycterus in the subgenus Psammocambeva of Trichomycterus, from eastern Brazil. Phylogenetic analyses, performed here, using a multigene data set for a broad trichomycterine sample, corroborate T. astromycterus as a member of Psammocambeva, reinforcing the importance of molecular data for inferring trichomycterine relationships but showing that osteological data alone may infer correctly phylogenetic placements when using broad comparative databases.

A new candiru of the genus Paracanthopoma (Siluriformes: Trichomycteridae) from the Araguaia River basin, central Brazil.

A new species of the candiru genus Paracanthopoma is described from the floodplains of the Bananal Island, a transition area between the Cerrado and Amazon, in the Araguaia River basin, central Brazil. Paracanthopoma cangussu sp. nov. is distinguished from its congeners, Paracanthopoma parva and Paracanthopoma saci, by the presence of seven opercular odontodes, five dentary teeth, five median premaxillary teeth, and first dorsal-fin pterygiophore in a vertical through the centrum of the 23th or 24th vertebra. It is further distinguished from each congener by an exclusive combination of character states, comprising the number of vertebrae, number of precaudal vertebrae, number of dorsal procurrent caudal-fin rays, number of ventral procurrent caudal-fin rays, number of dorsal-fin rays, disposition of pores on the cephalic portion of the latero-sensory system, absence of an anterior process on the anterior margin of parieto-supraoccipital, number of dorsal-fin pteryigiophores and number of interopercular odontodes. Although vandelliines are known for being exclusively hematophagous, with guts gorged with blood, two cleared and stained specimens of P. cangussu sp. nov. had Chironomidae larvae (Insecta) on their guts. Because most specimens of P. cangussu sp. nov. were collected with stomachs filled with blood, it was hypothesized that the species feeds accidentally or occasionally on insects.

Phylogenetic Position of Trichomycterus payaya and Examination of Osteological Characters Diagnosing the Neotropical Catfish Genus Ituglanis (Siluriformes: Trichomycteridae).

The Trichomycterinae is among the most diverse catfish groups in the world, with interesting ecological specializations; however, the taxonomy of Trichomycterinae is still problematic, mainly due to unclear limits and diagnoses of the eight included genera. Herein we infer the phylogenetic position and generic placement of Trichomycterus payaya, a recently described species from north-eastern Brazil, with unique morphological features among congeners. A multigene analysis including fragments of two nuclear and two mitochondrial genes (total of 2974 bp) for 53 trichomycterine taxa and three outgroups clearly supports inclusion of T. payaya in Ituglanis, a trichomycterine genus containing 29 valid species, which is corroborated by osteological characters. An examination of osteological characters used to diagnose Ituglanis in its original description indicates that a rudimentary or absent posterior cranial fontanel is synapomorphic for Ituglanis, but this is reversed in I. payaya; an anteriorly directed antero-lateral extremity of the sphenotic-prootic-pterosphenoid complex and a narrow and long lateral process of the parurohyal are synapomorphic for Ituglanis, but homoplastically occurring in other trichomycterids; and the presence of a deep medial concavity on the autopalatine is ambiguous to diagnose Ituglanis by occurring in other closely related trichomycterine taxa. Ituglanis is also distinguishable from other trichomycterines by a unique shape of the metapterygoid and by a reduced number of ribs. The analysis supports a clade, comprising I. payaya and I. paraguassuensis, that is endemic to the Chapada Diamantina, in the semiarid Caatinga of north-eastern Brazil, reinforcing the importance of this region for trichomycterid diversification. By integrating molecular analysis and comparative morphology, the present study provides a more solid basis for delimiting Ituglanis, creating a better taxonomical resolution of the Trichomycterinae, although much more research is necessary to reach a consistent generic classification for the entire subfamily.

Youth diet quality and hazard of mood disorder in adolescence and adulthood among an Australian cohort.

BACKGROUND: Prospective studies on youth diet and mood disorders outcomes are limited. We examined if youth diet quality was associated with mood disorder onset over a 25-year follow-up period. METHODS: In 1985, Australian participants (aged 10-15 years) completed a 24-hour food record. A validated 100-point Dietary Guidelines Index (DGI) assessed diet quality. In 2009-11, 1005 participants (aged 33-41 years) completed the lifetime Composite International Diagnostic Interview for age of first DSM-IV defined mood disorder (depression or dysthymia). Cox proportional hazards regression estimated hazard of mood disorder during the 25-year follow-up according to baseline DGI score. Sensitivity analyses censored the study at 5, 10, and 15 years after baseline and used log binomial regression to estimate relative risk (RR). Covariates included baseline negative affect, BMI, academic performance, smoking, breakfast eating, physical activity, and socioeconomic status. RESULTS: The mean(SD) youth DGI score was 45.0(11.5). A 10-point higher DGI was not associated with hazard of mood disorder onset over the 25-year follow-up (Hazard Ratio (HR):1.00; 95% Confidence Interval (CI):0.89-1.13). The only indication that higher DGI might be associated with lower risk of mood disorder was within the first 5 years after baseline and this was not statistically significant (RR=0.85; 95% CI:0.60-1.18). LIMITATIONS: Loss-to-follow-up. A single 24-hour food record may not represent usual diet. CONCLUSION: Youth diet did not predict mood disorders in adulthood. The suggestions of a lower risk of mood disorder during late adolescence highlights that further prospective studies are needed.

Relationships and Description of a New Species of Trichomycterus (Siluriformes: Trichomycteridae) from the Rio Paraíba do Sul basin, South-eastern Brazil.

A phylogenetic analysis using fragments of two nuclear and two mitochondrial genes strongly supported sister group relationships between a new species and Trichomycterus albinotatus, corroborated by unique colour patterns of adult specimens and juveniles, and morphology of the autopalatine bone. The new species is distinguished from its closest congener, T. albinotatus, by details of the colouration and number of branchiostegal rays. Both the new species and T. albinotatus are endemic to the Rio Paraíba do Sul basin, in the Atlantic Forest of south-eastern Brazil, but occur in distant and disjunct areas. The new species, herein described, is endemic to the upper section of the Rio Grande drainage, a right tributary of the lower Rio Paraíba do Sul, an area situated in the Órgãos Mountain Range. Trichomycterus albinotatus is endemic to an area about 200 km across, in the upper section of the Rio Preto that drains the Itatiaia Massif. However, both species are only known from localities above 1100 m asl, suggesting that they cannot survive in ecological conditions at lower altitudes. This study indicates that efforts are necessary to provide more accurate data on the species diversity and distribution of Trichomycterus in the biologically diverse and endangered Atlantic Forest of south-eastern Brazil.

An eating pattern characterised by skipped or delayed breakfast is associated with mood disorders among an Australian adult cohort.

BACKGROUND: Meal timing may influence food choices, neurobiology and psychological states. Our exploratory study examined if time-of-day eating patterns were associated with mood disorders among adults. METHODS: During 2004-2006 (age 26-36 years) and 2009-2011 (follow-up, age 31-41 years), N = 1304 participants reported 24-h food and beverage intake. Time-of-day eating patterns were derived by principal components analysis. At follow-up, the Composite International Diagnostic Interview measured lifetime mood disorder. Log binomial and adjacent categories log-link regression were used to examine bidirectional associations between eating patterns and mood disorder. Covariates included sex, age, marital status, social support, education, work schedule, body mass index and smoking. RESULTS: Three patterns were derived at each time-point: Grazing (intake spread across the day), Traditional (highest intakes reflected breakfast, lunch and dinner), and Late (skipped/delayed breakfast with higher evening intakes). Compared to those in the lowest third of the respective pattern at baseline and follow-up, during the 5-year follow-up, those in the highest third of the Late pattern at both time-points had a higher prevalence of mood disorder [prevalence ratio (PR) = 2.04; 95% confidence interval (CI) 1.20-3.48], and those in the highest third of the Traditional pattern at both time-points had a lower prevalence of first onset mood disorder (PR = 0.31; 95% CI 0.11-0.87). Participants who experienced a mood disorder during follow-up had a 1.07 higher relative risk of being in a higher Late pattern score category at follow-up than those without mood disorder (95% CI 1.00-1.14). CONCLUSIONS: Non-traditional eating patterns, particularly skipped or delayed breakfast, may be associated with mood disorders.

Description of a new species of cynopoeciline killifish (Cyprinodontiformes, Aplocheilidae), possibly extinct, from the Atlantic Forest of south-eastern Brazil.

Specimens found between 1985 and 1988 in the Magé River Basin, south-eastern Brazil were misidentified as L. splendens. The recent rediscovery of other specimens in the Estrela River Basin near the type locality of L. splendens has clarified the species' concept, making it possible to recognise the Magé River Basin specimens as a new species. The new species is herein described as Leptopanchax sanguineus sp. nov. and is distinguished from all other cynopoecilines by a unique colour pattern in males, including red bars with sinuous margins. It was collected in a well-preserved, temporary shallow swampy area within dense moist forest, but since 1990 the species has not been found again. Leptopanchax sanguineus sp. nov. is one of three species of cynopoeciline killifishes living in lowland moist forests of the coastal plains of Rio de Janeiro State, where the greatest diversity of endemic cynopoecilines is concentrated. Each of these species has been recorded a single time in the last 30 years, a surprisingly low record attributable to intense deforestation during the last several decades resulting in small fragmented lowland moist forests of today. This study indicates that seasonal killifishes adapted to uniquely live in this kind of habitat should be regarded with special concern in studies evaluating conservation priorities.

Rediscovery of Leptopanchax splendens (Cyprinodontiformes: Aplocheilidae): a seasonal killifish from the Atlantic Forest of south-eastern Brazil that was recently considered extinct.

A recent collection of the seasonal killifish found Leptopanchax splendens c. 5 km from the type locality, 74 years after its last record. The species was historically common in its type locality, the Estrela River basin in south-eastern Brazil, until 1950, after which it was not encountered and thought to have become extinct due to widespread deforestation and urbanization in the region. Despite the rediscovery, this study finds that other recently published reports of L. splendens are misidentifications.

Cryptic species diversity in the Hypsolebiasmagnificus complex, a clade of endangered seasonal killifishes from the São Francisco River basin, Brazilian Caatinga (Cyprinodontiformes, Aplocheilidae).

A great diversity of animal species adapted to life in the semi-arid Caatinga of northeastern Brazil, including seasonal killifishes, has been reported in the last three decades. More recently, field and molecular data have shown a high occurrence of cryptic species. The killifish group herein analysed, the Hypsolebiasmagnificus species complex, is endemic to the middle and southern portion of the Caatinga, occupying about 120 km along the floodplains of the middle São Francisco River and some adjacent tributaries. Species of this complex are rare and presently considered threatened with extinction, being uniquely found in pools protected by trees and bushes. Single-locus delimitation methods were used to test species limits of populations displaying different colour patterns along the whole distribution of the complex. All analyses consistently supported the three nominal species and two new, herein described: H.gardneri Costa, sp. n., from the floodplains of the middle São Francisco River and H.hamadryades Costa, sp. n., from the Gorotuba River floodplains. The phylogenetic analysis highly supports H.hamadryades as sister to a clade comprising H.gardneri and H.harmonicus. Our field observations suggest that H.hamadryades is a miniature species. This study indicates that the H.magnificus complex comprises cryptic species apparently endemic to small areas and extremely vulnerable to environmental changes, deserving high concern.

Multigene phylogeny supports diversification of four-eyed fishes and one-sided livebearers (Cyprinodontiformes: Anablepidae) related to major South American geological events.

The high diversity of Neotropical fishes has been attributed to major South American palaeogeographic events, such as Andean uplift, rise of the Isthmus of Panama and marine transgressions. However, the unavailability of temporal information about evolution and diversification of some fish groups prevents the establishment of robust hypotheses about correlations between species diversification and proposed palaeogeographical events. One example is the Anablepidae, a family of teleost fishes found mostly in coastal habitats of Central and South America, but also in some inner river basins of South America. Historical aspects of the distribution patterns of the Anablepidae were never analysed and no accurate estimation of time of its origin and diversification is presently available. A multi-gene analysis was performed to estimate Anablepidae phylogenetic position, age and biogeography, comprising seven nuclear genes. The suborder Cyprinodontoidei was recovered in three major clades, one comprising all the Old World Cyprinodontoidei and two comprising New World lineages. Anablepidae was recovered as the sister group of the New World Poeciliidae, with the Amazonian genus Fluviphylax as their sister group. The ages found for the origin and diversification of Cyprinodontiformes were congruent with the pattern recorded for other vertebrate groups, with an origin anterior to the Cretaceous-Paleogene (K-Pg) transition and diversification during the Paleogene. The age estimated for the split between the Atlantic and Pacific lineages of Anableps was congruent with the rise of Panamanian Isthmus. The results suggest Miocene marine transgressions as determinant to the current distribution of Jenynsia.

Synchronic historical patterns of species diversification in seasonal aplocheiloid killifishes of the semi-arid Brazilian Caatinga.

The Caatinga is the largest nucleus of seasonally dry tropical forests in South America, but little is known about the evolutionary history and biogeography of endemic organisms. Evolutionary diversification and distribution of terrestrial vertebrates endemic to the Caatinga have been explained by palaeogeographical Neogene episodes, mostly related to changes in the course of the São Francisco River, the largest river in the region. Our objective is to estimate the timing of divergence of two endemic groups of short-lived seasonal killifishes inhabiting all ecoregions of the Caatinga, testing the occurrence of synchronic events of spatial diversification in light of available data on regional palaeogeography. We performed independent time-calibrated phylogenetic molecular analyses for two clades of sympatric and geographically widespread seasonal killifishes endemic to the Caatinga, the Hypsolebias antenori group and the Cynolebias alpha-clade. Our results consistently indicate that species diversification took place synchronically in both groups, as well as it is contemporary to diversification of other organisms adapted to life in the semi-arid Caatinga, including lizards and small mammals. Both groups originated during the Miocene, but species diversification started between the Late Miocene and Early Pliocene, when global cooling probably favoured the expansion of semi-arid areas. Synchronic diversification patterns found are chronologically related to Tertiary palaeogeographical reorganizations associated to continental drift and to Quaternary climatic changes, corroborating the recent proposal that South American biodiversity has been continuously shaped between the Late Paleogene and Pleistocene.

Molecular phylogeny and timing of diversification in South American Cynolebiini seasonal killifishes.

The rich biological diversity of South America has motivated a series of studies associating evolution of endemic taxa with the dramatic geologic and climatic changes that occurred during the Cainozoic. The organism here studied is the killifish tribe Cynolebiini, a group of seasonal fishes uniquely inhabiting temporary pools formed during the rainy seasons. The Cynolebiini are found in open vegetation areas inserted in the main tropical and subtropical South American phytogeographical regions east of the Andes. Here, we present the first molecular phylogeny sampling all the eight genera of the Cynolebiini, using fragments of two mitochondrial and four nuclear genes for 35 species of Cynolebiini plus 19 species as outgroups. The dataset, 4448bp, was analysed under Bayesian and maximum likelihood approaches, providing a relatively well solved tree, which retrieves high support values for the Cynolebiini and most included clades. The resulting tree was used to estimate the time of divergence in included lineages using two cyprinodontiform fossils to calibrate the tree. We further investigated historical biogeography through the likelihood-based DEC model. Our estimates indicate that divergence between the clades comprising New World and Old World aplocheiloids occurred during the Eocene, about 50Mya, much more recent than the Gondwanan fragmentation scenario assumed in previous studies. This estimation is nearly synchronous to estimated splits involving other South American and African vertebrate clades, which have been explained by transoceanic dispersal through an ancient Atlantic island chain during the Palaeogene. We estimate that Cynolebiini split from its sister group Cynopoecilini in the Oligocene, about 25Mya and that Cynolebiini started to diversify giving origin to the present genera during the Miocene, about 20-14Mya. The Cynolebiini had an ancestral origin in the Atlantic Forest and probably were not present in the open vegetation formations of central and northeastern South America until the Middle Miocene, when expansion of dry open vegetation was favoured by cool temperatures and strike seasonality. Initial splitting between the genera Cynolebias and Simpsonichthys during the Miocene (about 14Mya) is attributed to the uplift of the Central Brazilian Plateau.

Three new species of the killifish genus Melanorivulus from the central Brazilian Cerrado savanna (Cyprinodontiformes, Aplocheilidae).

Three new species are described from the Neotropical region comprising the Cerrado savannas of the central Brazilian plateaus, which is among the most important biodiversity centres in the world. These species are considered closely related to Melanorivulus dapazi from the same region, with which they share the presence of a rudimentary interarcual cartilage and a dark reddish brown distal margin on the male anal fin. The group comprising Melanorivulus dapazi and the three new species is here named as the Melanorivulus dapazi species group. Melanorivulus ignescenssp. n., from the upper Rio Araguaia basin, is distinguished from all other species of the Melanorivulus dapazi group by the anal-fin colour pattern in males; Melanorivulus flavipinnissp. n. and Melanorivulus regularissp. n. from the Rio Paraguai basin are distinguished from all other congeners of the Melanorivulus dapazi group by the colour pattern of the caudal fin and number of scales in the longitudinal series, respectively. All the new species are further unambiguously diagnosed by unique combinations of morphological characters, including meristic and morphometric data, and colour patterns. This study reinforces the importance of using live colour patterns to diagnose species and species groups of the genus Melanorivulus, but also indicates that osteological characters may be informative for species diagnosis. This study confirms the high diversity of species of Melanorivulus in the central Brazilian Cerrado plateaus already reported in previous studies, indicating that endemic species are often restricted to short segments of a single river drainage.

Inferring Evolution of Habitat Usage and Body Size in Endangered, Seasonal Cynopoeciline Killifishes from the South American Atlantic Forest through an Integrative Approach (Cyprinodontiformes: Rivulidae).

Cynopoecilines comprise a diversified clade of small killifishes occurring in the Atlantic Forest, one of the most endangered biodiversity hotspots in the world. They are found in temporary pools of savannah-like and dense forest habitats, and most of them are highly threatened with extinction if not already extinct. The greatest gap in our knowledge of cynopoecilines stems from the absence of an integrative approach incorporating molecular phylogenetic data of species still found in their habitats with phylogenetic data taken from the rare and possibly extinct species without accessible molecular information. An integrative analysis combining 115 morphological characters with a multigene dataset of 2,108 bp comprising three nuclear loci (GLYT1, ENC1, Rho), provided a robust phylogeny of cynopoeciline killifishes, which was herein used to attain an accurate phylogenetic placement of nearly extinct species. The analysis indicates that the most recent common ancestor of the Cynopoecilini lived in open vegetation habitats of the Atlantic Forest of eastern Brazil and was a miniature species, reaching between 25 and 28 mm of standard length. The rare cases of cynopoecilines specialized in inhabiting pools within dense forests are interpreted as derived from four independent evolutionary events. Shifts in habitat usage and biogeographic patterns are tentatively associated to Cenozoic paleogeographic events, but the evolutionary history of cynopoecilines may be partially lost by a combination of poor past sampling and recent habitat decline. A sharp evolutionary shift directed to increased body size in a clade encompassing the genera Campellolebias and Cynopoecilus may be related to a parallel acquisition of an internally-fertilizing reproductive strategy, unique among aplocheiloid killifishes. This study reinforces the importance of adding morphological information to molecular databases as a tool to understand the biological complexity of organisms under intense pressure from loss of habitat.

Molecular phylogeny and evolution of internal fertilization in South American seasonal cynopoeciline killifishes.

Internal fertilization is a widespread mode of reproduction in chondrichthyans and tetrapods, but uncommon in actinopterygian fishes. In killifishes of the suborder Aplocheiloidei, internal fertilization is restricted to two genera, Campellolebias and Cynopoecilus, both containing species adapted to life in seasonal pools of subtropical South America and exhibiting elaborated inseminating structures. Phylogenetic studies involving these genera are scarce and limited to morphological characters and fragments of mitochondrial DNA sequences available for a few taxa, providing incongruent results and thus impeding hypotheses on the evolution of insemination and related morphological traits. We analyzed three nuclear loci (GLYT1, ENC1, Rho) for 13 aplocheiloid taxa obtaining the first well-supported phylogeny for cynopoecilines, thus providing a significant background to interpret evolutionary changes within the group. Like in killifishes of the suborder Cyprinodontoidei, the evolution of internal fertilization in aplocheiloids is associated with deep changes in the structure of male anal fin. The phylogenetic analyses indicate that internal fertilization corresponds to a single evolutionary event during the evolution of aplocheiloid killifishes. The analyses also indicate that male specialized muscle characters, comprising a muscular ejaculatory pump in the urogenital region and hypertrophied inclinatores and depressores anales, arose in the ancestor of the clade comprising Campellolebias and Cynopoecilus. On the other hand, anal fin specialized structures including the male inseminating tube of Campellolebias and the male inseminating fan of Cynopoecilus evolved independently in each genus.

Determination of the allelic frequency in Smith-Lemli-Opitz syndrome by analysis of massively parallel sequencing data sets.

Data from massively parallel sequencing or 'Next Generation Sequencing' of the human exome has reached a critical mass in both public and private databases, in that these collections now allow researchers to critically evaluate population genetics in a manner that was not feasible a decade ago. The ability to determine pathogenic allele frequencies by evaluation of the full coding sequences and not merely a single nucleotide polymorphism (SNP) or series of SNPs will lead to more accurate estimations of incidence. For demonstrative purposes, we analyzed the causative gene for the disorder Smith-Lemli-Opitz Syndrome (SLOS), the 7-dehydrocholesterol reductase (DHCR7) gene and determined both the carrier frequency for DHCR7 mutations, and predicted an expected incidence of the disorder. Estimations of the incidence of SLOS have ranged widely from 1:10,000 to 1:70,000 while the carrier frequency has been reported as high as 1 in 30. Using four exome data sets with a total of 17,836 chromosomes, we ascertained a carrier frequency of pathogenic DHRC7 mutations of 1.01%, and predict a SLOS disease incidence of 1/39,215 conceptions. This approach highlights yet another valuable aspect of the exome sequencing databases, to inform clinical and health policy decisions related to genetic counseling, prenatal testing and newborn screening.