Whole-genome sequencing reveals the extent of heterozygosity in a preferentially self-fertilizing hermaphroditic vertebrate.

The mangrove rivulus, Kryptolebias marmoratus, is one of only two self-fertilizing hermaphroditic fish species and inhabits mangrove forests. While selfing can be advantageous, it reduces heterozygosity and decreases genetic diversity. Studies using microsatellites found that there are variable levels of selfing among populations of K. marmoratus, but overall, there is a low rate of outcrossing and, therefore, low heterozygosity. In this study, we used whole-genome data to assess the levels of heterozygosity in different lineages of the mangrove rivulus and infer the phylogenetic relationships among those lineages. We sequenced whole genomes from 15 lineages that were completely homozygous at microsatellite loci and used single nucleotide polymorphisms (SNPs) to determine heterozygosity levels. More variation was uncovered than in studies using microsatellite data because of the resolution of full genome sequencing data. Moreover, missense polymorphisms were found most often in genes associated with immune function and reproduction. Inferred phylogenetic relationships suggest that lineages largely group by their geographic distribution. The use of whole-genome data provided further insight into genetic diversity in this unique species. Although this study was limited by the number of lineages that were available, these data suggest that there is previously undescribed variation within lineages of K. marmoratus that could have functional consequences and (or) inform us about the limits to selfing (e.g., genetic load, accumulation of deleterious mutations) and selection that might favor the maintenance of heterozygosity. These results highlight the need to sequence additional individuals within and among lineages.

Análise sazonal da produção e da atividade enzimática de látex fresco coletado de frutos de plantas femininas e hermafroditas de mamão (Carica papaya L. ) / Seasonal analysis of yield and enzyme activity of fresh latex collected from fruits of female and hermaphrodite plants of papaya (Carica papaya L. )

RESUMO O látex obtido do fruto de Carica papaya L. (mamão) é de grande importância industrial e farmacêutica. Sua obtenção, através do cultivo dessa espécie, depende de vários fatores ainda pouco estudados. Nesse sentido, o presente trabalho tem por objetivo avaliar e comparar plantas femininas e hermafroditas de C. papaya em relação à produção de látex e sua atividade enzimática em coletas semanais e consecutivas durante o 12º mês de cultivo (verão) e no decorrer do segundo ano de desenvolvimento das plantas, e em mais três coletas abrangendo as demais estações do ano (outono, inverno e primavera). Os resultados mostraram que, em quatro coletas semanais e sucessivas durante o verão, a massa de látex da primeira coleta foi superior às demais para plantas femininas. Plantas hermafroditas tiveram comportamento oscilante para esta variável. Plantas femininas tiveram médias de produção superiores comparadas com as hermafroditas. As médias das atividades enzimáticas desse período se mostraram superiores para plantas hermafroditas. Nas coletas estacionais foi observado que plantas hermafroditas têm um comportamento mais oscilante em relação à produção de látex e atividade enzimática. Plantas femininas produzem, em média, maior massa de látex e são mais constantes na produção. Nas estações avaliadas, observaram-se semelhanças nas médias das atividades enzimáticas entre plantas femininas e hermafroditas.

ABSTRACT The latex obtained from the fruit of Carica papaya L. (papaya) is of great industrial and pharmaceutical importance. Its obtainment, through the cultivation of this specie, depends on several factors still poorly studied. In this sense, this study aims to evaluate and compare hermaphrodite and female plants of C. papaya for the production of latex and its enzymatic activity in weekly and consecutive collections of fruits during the 12th month of cultivation (summer) and during the second year of the plant´s development, in three collections covering the other seasons (autumn, winter and spring). The results showed that, in four successive weekly tapping during the summer, the latex mass of the first collection was superior to the others, for female plants. Hermaphrodite plants had oscillating behavior for this variable. Female plants had higher production averages, compared with the hermaphrodites ones. The averages of the enzymatic activities of this period were higher for hermaphrodite plants. The seasonal tapping showed that hermaphrodite plants had oscillating behavior in the production of latex and enzyme activity. Female plants produced, on average, greater mass and were constant in latex production. In the evaluated seasons, similarities in the averages of the enzymatic activities between female and hermaphrodite plants were observed.

Review of Baeolidia, the largest genus of Aeolidiidae (Mollusca: Nudibranchia), with the description of five new species.

This paper discusses the systematics of the aeolid genus Baeolidia Bergh, 1888. To date, this monophyletic genus is the most diverse within Aeolidiidae with sixteen valid species. Excluding Baeolidia cryoporos Bouchet, 1977, the genus is restricted to the Indo-Pacific and Eastern Pacific. Species of Baeolidia show a huge intrageneric variability in several morphological characters. Only oral glands, if present, may distinguish Baeolidia from other aeolidiids genera. Aeolidiella occidentalis Bergh, 1875, Aeolidiella faustina Bergh, 1900 and Spurilla orientalis Bergh, 1905 are transferred to Baeolidia but they are considered nomina dubia. Five new species, Baeolidia rieae sp. nov., Baeolidia variabilis sp. nov., Baeolidia lunaris sp. nov., Baeolidia gracilis sp. nov. and Baeolidia scottjohnsoni sp. nov. are described.

Four new earthworm species of the genus Amynthas (Oligochaeta: Megascolecidae) from Kinmen, Taiwan.

Four new species of terrestrial earthworms belonging to the genus Amynthas were collected on the islands of Kinmen and Lieyu, Taiwan from March to November, 2008. They are Amynthas kinmenensis sp. nov., Amynthas wuhumontis sp. nov., Amynthas wujhouensis sp. nov., and Amynthas taiwumontis sp. nov. Amynthas kinmenensis sp. nov. is quadrithecal and is the most abundant earthworm widely distributed on the main island of Kinmen. It has numerous small genital papillae and is closely related to Amynthas polyglandularis (Tsai, 1964) from northern Taiwan. Amynthas wuhumontis sp. nov. is sexthecal and is distributed only in areas around Mt. Wuhu and Mt. Taiwu in east Kinmen. It has male pores each surrounded by three genital papillae: one anterior, one posterior and one medial. Amynthas wujhouensis sp. nov. and Amynthas taiwumontis sp. nov. are octothecal. The former has a sporadic distribution in Kinmen while the latter was only found in areas around Mt. Taiwu. Amynthas wujhouensis sp. nov. has a pair of large genital papillae closely adjacent to the crescent or semicircular shaped male porophores in XVIII. Amynthas taiwumontis sp. nov. has simple male pore structure and no genital papillae or genital markings. DNA barcodes (the 5' end sequences of the mitochondrial cytochrome c oxidase subunit 1 gene) from type specimens and other materials of the first three species are also reported.

Description of two new Discocelis species (Polycladida: Acotylea: Discocelidae) from the Persian Gulf with a review of the genus.

Two new polyclad species, from northern intertidal zone and shallow rocky shores of the Persian Gulf, Discocelispersica sp. nov. and Discocelis hollemani sp. nov., are described. D. persica possesses a thick and broadly oval body tapering somewhat posteriorly, without any obvious color pattern; with marginal eyes extended around the anterior margin of the body; cerebral eyes forming two clusters, each further subdivided into anterior and posterior groups, about 100 eyespots at the anterior group and 55 eyespots at the posterior groups; mouth at the posterior end of the pharynx; male atrium with three to four distinct lobes, with numerous prostatoid organs of two distinct sizes, without villus-like projections; and with a horseshoe-shaped Lang's vesicle. D. hollemani characterized by a thick and broadly oval body, not tapering antro-posteriorly, without any obvious color pattern; marginal eyes extended to the vicinity of the posterior end of pharynx; the cerebral eyes forming two clusters, each further subdivided into anterior and posterior groups in relation to the cerebral organ, about 50 eyespots at the anterior group and 20 eyespots at the posterior groups; mouth at the posterior end of the pharynx; the male atrium with two distinct lobes, with numerous prostatoids of two distinct sizes and different contents; villus-like projections absent, and with a horseshoe-shaped Lang's vesicle.

Reproductive cycle and embryonic development of the gastropod Melampus coffeus (Linnaeus, 1758) (Ellobiidae) in the Brazilian Northeast / Ciclo reprodutivo e desenvolvimento embrionário do gastrópode Melampus coffeus (Linnaeus, 1758) (Ellobiidae) no Nordeste do Brasil

Melampus coffeus belongs to a primitive group of pulmonate mollusks found mainly in the upper levels of the marine intertidal zone. They are common in the neotropical mangroves. Little is known about the biology of this species, particularly about its reproduction. The aim of this study was to 1) characterize the morphology and histology of M. coffeus' gonad; 2) describe the main gametogenesis events and link them to a range of maturity stages; 3) chronologically evaluate the frequency of the different maturity stages and their relation to environmental factors such as water, air and sediment temperatures, relative humidity, salinity and rainfall; and 4) characterize M. coffeus' spawning, eggs and newly hatched veliger larvae. Samples were collected monthly between February, 2007 and January, 2009 from the mangroves of Praia de Arpoeiras, Acaraú County, State of Ceará, northeastern Brazil. The characterization of the gonad development stages was carried out using routine histological techniques. The results of this study show that Melampus coffeus is a simultaneous hermaphrodite. The follicles have masculine and feminine elements, interleaved within the gonad. M. coffeus presents a well-defined synchronous reproductive cycle, showing successive maturation, release and resting periods. The average diameter of the oocytes was negatively correlated with salinity and positively correlated with rainfall. The results show that no reproductive activity occurs during periods of drought. After the dry season, the increasing rainfall levels and reduced salinity lead to the appearance of very dense populations, predominantly composed of small individuals.

Melampus coffeus encontra-se em um grupo primitivo de moluscos pulmonados, primordialmente marinhos, habitantes dos níveis superiores da zona entremarés, comum em manguezais do Oceano Atlântico. Pouco se sabe sobre a biologia da espécie, em especial, sobre a sua reprodução. Os objetivos deste trabalho foram: 1) caracterizar morfo-histologicamente a gônada de M. coffeus; 2) descrever os principais eventos da gametogênese e associá-los a uma escala de estágios de maturidade; 3) avaliar temporalmente a frequência dos estágios de maturidade e sua possível relação com os fatores ambientais, como a temperatura da água, do ar e do sedimento, a umidade relativa, a salinidade e a pluviosidade, e 4) caracterizar a postura, os ovos e a véliger recém-eclodida de M. coffeus. Foram realizadas coletas mensais de fevereiro de 2007 a janeiro de 2009, no manguezal da Praia de Arpoeiras, município de Acaraú-Ceará, na Região Nordeste do Brasil. A caracterização das fases de desenvolvimento da gônada foi realizada utilizando-se técnicas histológicas de rotina. Os resultados deste estudo mostram que Melampus coffeus é um hermafrodita simultâneo. Os folículos apresentam elementos masculinos e femininos, distribuindo-se na gônada intercalados radialmente. M. coffeus apresenta um ciclo reprodutivo sincrônico bem definido, evidenciando-se períodos sucessivos de amadurecimento, de liberação e de repouso. O diâmetro médio dos oócitos apresentou correlação negativa com a salinidade e positiva com a pluviosidade. Os resultados indicam que, nos períodos de estiagem, não há atividade reprodutiva. Após essa estação, quando os valores de pluviosidade aumentam e a salinidade diminui, as populações são bastante densas e predominam indivíduos pequenos.

Twenty-four years in the mud: what have we learned about the natural history and ecology of the mangrove rivulus, Kryptolebias marmoratus?

Although first described in 1880, Kryptolebias marmoratus avoided scientific scrutiny until 1961, when it was identified as the only known selfing hermaphroditic vertebrate. The subsequent intense interest in this fish as a laboratory animal, continuing to this day, might explain the paucity of wild collections, but our collective knowledge now suggests that the inherent difficulty of wild collection is more a matter of "looking in all the wrong places." Long thought to be rare in the mangroves, and it is rare in certain human-impacted habitats, K. marmoratus can be quite abundant, but in microhabitats not typically targeted by ichthyologists: ephemeral pools at higher elevations in the swamp, crab burrows, and other fossorial or even terrestrial haunts. Field studies of this enigmatic fish have revealed almost amphibious behaviors. During emersion these fish tolerate extended dry periods. In water, they are exposed to temperature extremes, high levels of hydrogen sulfide, and depleted dissolved oxygen. Finally, their catholic diet and a geographically variable sex life completes a portrait of an unusual animal. A clearer picture is emerging of adult life, with initial population density estimates now known and some indication of high population turnover in burrows, but juvenile habitat and adult oviposition sites remain unknown.

Extreme gender flexibility: using a phylogenetic framework to infer the evolution of variation in sex allocation, phylogeography, and speciation in a genus of bidirectional sex changing fishes(Lythrypnus, Gobiidae).

The genus Lythrypnus is a group of marine gobies that exhibit extreme gender flexibility as bidirectional sex changers. The genus consists of 20 described species and several undescribed species that are distributed in the Americas. Five species have been characterized with respect to sex allocation and gonad morphology. The hormonal, morphological, and behavioral aspects of sex change have been studied extensively for one species, L. dalli. These data, however, have not been interpreted in an evolutionary context because a phylogenetic hypothesis has not previously been proposed for the genus Lythrypnus. We propose the first phylogenetic hypothesis for the genus based on molecular data from three mitochondrial genes (12s, ND2, and Cytb), one nuclear gene (Rag1) and one nuclear intron (S7). We also include three previously undescribed Lythrypnus species. Our results support the monophyly of the genus with L. heterochroma, an Atlantic species, as the basal taxon. After the divergence of L. heterochroma, there are two main clades, one comprised of species distributed in the Atlantic, the other comprised of species distributed in the Pacific. These data indicate an Atlantic origin for the genus, followed by divergence after the closure of the Isthmus of Panama. Our data also support the monophyly of three previously described species complexes, the L. rhizophora complex and L. dalli complex in the Pacific, and the L. mowbrayi complex in the Atlantic. We mapped patterns of sex allocation within this genus onto the fully resolved and supported topology, and found that sexual plasticity and gender flexibility is likely a synapomorphy for the genus. Overall our results create a well-supported framework to understand the phylogeography of the genus, and to interpret the evolution of sex allocation in Lythrypnus gobies.

Heterodichogamy in Kingdonia (Circaeasteraceae, Ranunculales).

BACKGROUND AND AIMS: Preliminary field observations in 2001 and 2002 suggested that Kingdonia uniflora (Circaeasteraceae, Ranunculales) exhibits heterodichogamy, an unusual kind of reproductive heteromorphy, hitherto unreported in Ranunculales and known from only one other genus in basal eudicots. METHODS: During several subsequent years flowers were observed in the field. Flowers were fixed in FAA and studied with microtome sections series and with the scanning electron microscope. KEY RESULTS: The flowers proved to be heterodichogamous, with protandrous and protogynous morphs, which have a 1 : 1 ratio. Both morphs equally set fruit. Each year a single flower is formed at the tip of a rhizome or more rarely two flowers. The flowers are already open when they appear at the soil surface, before they are receptive and before pollen is dispersed. In both floral morphs the styles elongate early and the stigmas are positioned above the anthers before anthesis begins. In protogynous flowers the stigmas become receptive in this position; later the styles become reflexed and then the anthers dehisce. In contrast, in protandrous flowers the stamen filaments elongate during early anthesis such that the dehiscing anthers come to lie above the (still unreceptive) stigmas; after dehiscence of all anthers in a flower the styles begin to elongate and become receptive. CONCLUSIONS: This is the first record of heterodichogamy in a representative of Ranunculales, in an herbaceous eudicot, and in a plant with uniflorous ramets. The occurrence of heterodichogamy in Kingdonia in which clonal reproduction appears to be dominant might be an adaptation to avoid mating between the ramets from a common mother individual (genet).

Reproductive cycle and embryonic development of the gastropod Melampus coffeus (Linnaeus, 1758) (Ellobiidae) in the Brazilian Northeast.

Melampus coffeus belongs to a primitive group of pulmonate mollusks found mainly in the upper levels of the marine intertidal zone. They are common in the neotropical mangroves. Little is known about the biology of this species, particularly about its reproduction. The aim of this study was to 1) characterize the morphology and histology of M. coffeus' gonad; 2) describe the main gametogenesis events and link them to a range of maturity stages; 3) chronologically evaluate the frequency of the different maturity stages and their relation to environmental factors such as water, air and sediment temperatures, relative humidity, salinity and rainfall; and 4) characterize M. coffeus' spawning, eggs and newly hatched veliger larvae. Samples were collected monthly between February, 2007 and January, 2009 from the mangroves of Praia de Arpoeiras, Acaraú County, State of Ceará, northeastern Brazil. The characterization of the gonad development stages was carried out using routine histological techniques. The results of this study show that Melampus coffeus is a simultaneous hermaphrodite. The follicles have masculine and feminine elements, interleaved within the gonad. M. coffeus presents a well-defined synchronous reproductive cycle, showing successive maturation, release and resting periods. The average diameter of the oocytes was negatively correlated with salinity and positively correlated with rainfall. The results show that no reproductive activity occurs during periods of drought. After the dry season, the increasing rainfall levels and reduced salinity lead to the appearance of very dense populations, predominantly composed of small individuals.

The evolution of euhermaphroditism in caridean shrimps: a molecular perspective of sexual systems and systematics.

BACKGROUND: The hippolytid genus Lysmata is characterized by simultaneous hermaphroditism, a very rare sexual system among Decapoda. Specialized cleaning behavior is reported in a few pair-living species; these life history traits vary within the genus. Unfortunately, the systematics of Lysmata and the Hippolytidae itself are in contention, making it difficult to examine these taxa for trends in life history traits. A phylogeny of Lysmata and related taxa is needed, to clarify their evolutionary relationships and the origin of their unique sexual pattern. In this study, we present a molecular phylogenetic analysis among species of Lysmata, related genera, and several putative hippolytids. The analysis is based upon DNA sequences of two genes, 16S mtDNA and nuclear 28S rRNA. Phylogenetic trees were estimated using Bayesian Inference, Maximum Likelihood, and Maximum Parsimony. RESULTS: Phylogenetic analysis of 29 species of Lysmata, eight genera of Hippolytidae and two genera of Barbouriidae based on a single (16S, 28S) and combined gene approach (16S+28S) indicates that three groups of Lysmata differentiate according to antennular morphology: (1) Lysmata, having a multi-segmented accessory branch, (2) Hippolysmata (prior to Chace 1972), with a one-segmented accessory branch, and (3) a third group of Lysmata outliers, with one-segmented unguiform accessory branch, and close affinity to the genera Exhippolysmata and Lysmatella. The monophyly of the clade bearing a multi-segmented accessory branch is robust. Within the short accessory branch clade, species with specialized cleaning behaviors form a monophyletic clade, however, the integrity of the clade was sensitive to alignment criteria. Other hippolytid and barbouriid genera used in the analysis are basal to these three groups, including one displaying simultaneous hermaphroditism (Parhippolyte). The two barbouriid species occur in a separate clade, but among hippolytid taxa. CONCLUSIONS: The data support the historical morphological division of Lysmata into clades based on accessory branch morphology. The position of the "cleaner" shrimps, indicates that specialized cleaning behavior is a derived trait. The topologies of the cladograms support the monophyly of the barbouriids, but do not support their elevation to familial status. Taxa ancestral to the genus Lysmata display simultaneous hermaphroditism, suggesting that this life history trait evolved outside the genus Lysmata.