Resurrection of the sea pen genus Ptilella Gray, 1870 and description of Ptilella grayi n. sp. from the NE Atlantic (Octocorallia: Pennatulacea)

The order Pennatulacea covers a group of specialized and morphologically distinct octocorals found in all oceans from intertidal areas to more than 6000 m in depth. Sea pens constitute an important structural component in marine soft-bottom communities by increasing the complexity of these environments. Despite being both morphologically distinctive and ecologically important, the taxonomy and systematics of sea pens is still poorly understood. Recent molecular studies have shown the existence of convergent morphological features, making the current familial distribution of genera unstable. The genus Pennatula Linnaeus, 1758 was one of the first described octocoral genera. It is the type genus of its family, Pennatulidae. Colonies of this genus have a characteristic morphology. Recent sampling efforts in the northeastern Atlantic have provided a number of colonies initially attributable to the genus Pennatula. Both morphological and molecular (mtMutS, Cox1 and 28S genes) study of this material supports the polyphyletic nature of this genus and the need to resurrect the genus Ptilella Gray, 1870 to accommodate these and other species. A new species, Ptilella grayi n. sp., is described and illustrated. The species Pennatula bayeri is proposed to be a junior synonym of Pennatula bellissima (here also considered in the genus Ptilella)

A New Species of Ovabunda (Octocorallia, Xeniidae) From the Andaman Sea, Thailand with Notes on the Biogeography of This Genus

A survey of xeniid octocorals was carried out in the waters off Southwestern Thailand in September, 2007. Microscopic investigation of the colonies revealed that three specimens belonged to the genus Ovabunda. Gross morphological examination is presented here accompanied by scanning electron micrographs of the sclerites. Molecular phylogenetic analysis showed identical genotypes at mtMutS, COI, and 28S rDNA for all three specimens and supports their generic assignment. Colony size and shape, sclerite size, and pinnule arrangement differ from nominal species of Ovabunda and thus a new species, O. andamanensis is introduced here. This work also presents a new eastern geographical record for the genus Ovabunda

Evolutionary dynamics of a common sub-Antarctic octocoral family

Sequence data were obtained for five different loci, both mitochondrial (cox1, mtMutS, 16S) and nuclear (18S, 28S rDNA), from 64 species representing 25 genera of the common deep-sea octocoral family Primnoidae. We tested the hypothesis that Primnoidae have an Antarctic origin, as this is where they currently have high species richness, using Maximum likelihood and Bayesian inference methods of phylogenetic analysis. Using a time-calibrated molecular phylogeny we also investigated the time of species radiation in sub-Antarctic Primnoidae. Our relatively wide taxon sampling and phylogenetic analysis supported Primnoidae as a monophyletic family. The base of the well-supported phylogeny was Pacific in origin, indicating Primnoidae sub-Antarctic diversity is a secondary species radiation. There is also evidence for a subsequent range extension of sub-Antarctic lineages into deep-water areas of the Indian and Pacific Oceans. Conservative and speculative fossil-calibration analyses resulted in two differing estimations of sub-Antarctic species divergence times. Conservative analysis suggested a sub-Antarctic species radiation occurred ∼52 MYA (95% HPD: 36–73 MYA), potentially before the opening of the Drake Passage and Antarctic Circumpolar Current (ACC) formation (41–37 MYA). Speculative analysis pushed this radiation back into the late Jurassic, 157 MYA (95% HPD: 118–204 MYA). Genus-level groupings were broadly supported in this analysis with some notable polyphyletic exceptions: Callogorgia, Fanellia, Primnoella, Plumarella, Thouarella. Molecular and morphological evidence supports the placement of Tauroprim

Sinularia Leptoclados (Ehrenberg, 1834) (Cnidaria: Octocorallia) Re-Examined

Sinularia leptoclados (Ehrenberg, 1834) is re-described. Sinularia leptoclados var. gonatodes Kolonko, 1926 is synonymized with S. maxima Verseveldt, 1977. Two new species of Sinularia with digitiform lobules, leptoclados-type surface clubs and unbranched interior spindles, are described. An updated maximum likelihood tree of Sinularia species with leptoclados-type clubs (clade 5C) based on two mitochondrial genes (mtMutS, COI) and a nuclear gene (28S rDNA) is presented

Fuzzy species limits in Mediterranean gorgonians (Cnidaria, Octocorallia): inferences on speciation processes

The study of the interplay between speciation and hybridization is of primary importance in evolutionary biology. Octocorals are ecologically important species whose shallow phylogenetic relationships often remain to be studied. In the Mediterranean Sea, three congeneric octocorals can be observed in sympatry: Eunicella verrucosa, Eunicella cavolini and Eunicella singularis. They display morphological differences and E.singularis hosts photosynthetic Symbiodinium, contrary to the two other species. Two nuclear sequence markers were used to study speciation and gene flow between these species, through network analysis and Approximate Bayesian Computation (ABC). Shared sequences indicated the possibility of hybridization or incomplete lineage sorting. According to ABC, a scenario of gene flow through secondary contact was the best model to explain these results. At the intraspecific level, neither geographical nor ecological isolation corresponded to distinct genetic lineages in E.cavolini. These results are discussed in the light of the potential role of ecology and genetic incompatibilities in the persistence of species limits.French National Research Agency (ANR) program Adacni (ANR) [ANR-12-ADAP-0016]CNRSHubert Curien 'Tassili' program [12MDU853]CCMAR Strategic Plan from Fundacao para a Ciencia e a Tecnologia-FCT [PEst-C/MAR/LA0015/2011,FEDERinfo:eu-repo/semantics/publishedVersio

Molecular Phylogenetic Evidence Supports a New Family of Octocorals and a New Genus of Alcyoniidae (Octocorallia: Alcyonacea)

Molecular phylogenetic evidence indicates that the octocoral family Alcyoniidae is highly polyphyletic, with genera distributed across Octocorallia in more than 10 separate clades. Most alcyoniid taxa belong to the large and poorly resolved Holaxonia–Alcyoniina clade of octocorals, but members of at least four genera of Alcyoniidae fall outside of that group. As a first step towards revision of the family, we describe a new genus, Parasphaerasclera gen. n., and family, Parasphaerascleridae fam. n., of Alcyonacea to accommodate species of Eleutherobia Pütter, 1900 and Alcyonium Linnaeus, 1758 that have digitiform to digitate or lobate growth forms, completely lack sclerites in the polyps, and have radiates or spheroidal sclerites in the colony surface and interior. Parasphaerascleridae fam. n. constitutes a well-supported clade that is phylogenetically distinct from all other octocoral taxa. We also describe a new genus of Alcyoniidae, Sphaerasclera gen. n., for a species of Eleutherobia with a unique capitate growth form. Sphaerasclera gen. n. is a member of the Anthomastus–Corallium clade of octocorals, but is morphologically and genetically distinct from Anthomastus Verrill, 1878 and Paraminabea Williams & Alderslade, 1999, two similar but dimorphic genera of Alcyoniidae that are its sister taxa. In addition, we have re-assigned two species of Eleutherobia that have clavate to capitate growth forms, polyp sclerites arranged to form a collaret and points, and spindles in the colony interior to Alcyonium, a move that is supported by both morphological and molecular phylogenetic evidenc

A unique horizontal gene transfer event has provided the octocoral mitochondrial genome with an active mismatch repair gene that has potential for an unusual self-contained function

Background: The mitochondrial genome of the Octocorallia has several characteristics atypical for metazoans, including a novel gene suggested to function in DNA repair. This mtMutS gene is favored for octocoral molecular systematics, due to its high information content. Several hypotheses concerning the origins of mtMutS have been proposed, and remain equivocal, although current weight of support is for a horizontal gene transfer from either an epsilonproteobacterium or a large DNA virus. Here we present new and compelling evidence on the evolutionary origin of mtMutS, and provide the very first data on its activity, functional capacity and stability within the octocoral mitochondrial genome

Filogenia molecular y estimación del tiempo de divergencia en pennatuláceos (Cnidaria: Octocorallia: Pennatulacea)

Pennatulaceans are an important component of benthic marine communities usually related to soft bottoms. Despite their important ecological role, as yet little is known about their origin and divergence time. The first attempts to establish phylogenetic relationships among genera date from the early 20th century, when only morphological characters were available. In the last decade, phylogenetic analyses based on mitochondrial DNA sequences from a selected number of species have proposed a different hypothetical ancestor for this group, but their intergeneric relationships remain obscure. The present study is based on a combination of mitochondrial and nuclear markers (mtMutS, Cox1 and 28S rDNA), adding new molecular information about the phylogenetic relationships among the pennatulacean genera, including 38 new sequences belonging to 13 different species. Some of the phylogenetic relationships inferred in the present study question the current classification of sea pens based on morphology (at different taxonomic levels), clearly indicating that the two main groups Sessiliflorae and Subselliflorae, some of their main families (e.g. Pennatulidae, Umbellulidae, Virgulariidae) and some genera (e.g. Umbellula, Veretillum) are non-monophyletic. In addition, the veretillids, traditionally considered the most primitive pennatulaceans, are not shown as the earliest-diverging taxon. Moreover, an analysis of divergence time performed here suggested that the origin of the pennatulaceans dates from the Lower Cretaceous (Berriasian, ~144 Ma), in agreement with their sparsely known fossil record, while the initial divergence of most extant genera occurred in the Oligocene and Miocene times.Los pennatuláceos son un componente importante de las comunidades bentónicas marinas generalmente relacionados con fondos blandos. A pesar de su importante papel ecológico, la información sobre su origen y tiempo de divergencia es aún escasa. Los primeros intentos de establecer relaciones filogenéticas entre géneros datan de principios del siglo XX, cuando sólo estaban disponibles caracteres morfológicos. En la última década, los análisis filogenéticos basados en secuencias de ADN mitocondrial procedentes de un limitado número de especies han propuesto un ancestro hipotético diferente para este grupo, pero sus relaciones intergenéricas permanecen oscuras. La presente investigación está basada en una combinación de marcadores mitocondriales y nuclear (mtMutS, Cox1 y ADNr 28S), aportando nueva información molecular sobre las relaciones filogenéticas entre los géneros de pennatuláceos, incluyendo 38 nuevas secuencias pertenecientes a 13 especies. Algunas de las relaciones filogenéticas inferidas en el presente estudio cuestionan la actual clasificación de las plumas de mar basada en la morfología (a diferentes niveles taxonómicos), indicando claramente que los dos grupos principales Sessiliflorae y Subselliflorae, algunas de sus principales familias (por ejemplo Pennatulidae, Umbellulidae, Virgulariidae) y algunos géneros (por ejemplo Umbellula, Veretillum) son no-monofiléticos. Asimismo, los veretílidos, tradicionalmente considerados los pennatuláceos más primitivos, no se muestran como el taxón divergente más antiguo. Además, un análisis del tiempo de divergencia realizado en este trabajo sugirió que el origen de los pennatuláceos data del Cretácico Inferior (Berriasiano, ~ 144 Ma), de acuerdo con su escasamente conocido registro fósil, mientras que la divergencia inicial de la mayoría de los géneros existentes ocurrió en tiempos del Oligoceno y Mioceno

The Role of Depth and Water Mass in the Evolution and Distribution of Deep-Sea Corals

The processes that control diversification and speciation in deep-sea species are poorly known. Here, we analyzed data produced by Restriction-Site Associated DNA Sequencing (RAD-Seq) of octocorals in the genus Paramuricea to elucidate diversification patterns and examine the role of environmental gradients in their evolution. The genus Paramuricea evolved around 8 MYA, with a high probability of a broad ancestral depth range from mesophotic depths to the deep sea. At around 1-2 MYA, the genus diversified across the continental slope of the deep North Atlantic, supporting the depth-differentiation hypothesis, with no invasions back into shallower depths (< 200 m). Diversification in the deep sea generally occurred from shallower, warmer waters to deeper, colder depths of the lower continental slope. We also found that the vertical structure of water masses was influential in shaping phylogeographic patterns across the North Atlantic Ocean, with clades found in either upper/intermediate or intermediate/deep water masses. Our data suggest that species diverged first because of environmental conditions, including depth, temperature, and/or water mass, and then diversified into different geographical regions multiple times. Our results highlight the role of the environment in driving the evolution and distribution of Paramuricea throughout the deep sea. Furthermore, our study supports prior work showing the utility of genomic approaches over the conventionally-used DNA barcodes in octocoral species delimitation.Temple University. College of Science and TechnologyBiolog

Phylogenetic and phylogeographic assessment of the temperate octocoral Eunicella verrucosa

The three-dimensional structure of gorgonian octocoral, like Eunicella, can provide vital habitat for other marine organisms and are thus considered ecosystem engineers. As they are ecosystem engineers, the conservation of Eunicella can deliver benefit to other marine organisms and thus their conservation can have a significant impact. Phylogenetic assessment of a species is pivotal in order to inform management efforts and conservation strategies accurately. Unfortunately, phylogenetic assessment of octocoral has been massively hindered by a lack of variation in their mitochondrial genomes. This is highly evident in the Eunicella genus, as previous studies have shown no variation in the mitochondrial protein-coding gene cox1. In Chapter 2, novel primers were successfully developed and exploited to explore the phylogenetic relationships between three predominant Atlantic-Mediterranean members of Eunicella (E. verrucosa, E. singularis and E. cavolini). This is one of the first studies to identify variation in the mitochondrial genomes of Eunicella. In Chapter 3, complete mitochondrial genomes of 19 E. verrucosa individuals were sequenced. Only two E. verrucosa genotypes were observed. 17 E. verrucosa individuals showed a widespread genotype and two E. verrucosa individuals, from Lion Rock, Isle of Scilly, southwest England, showed a unique genotype. Even compared to the known low levels of variation in the mitogenomes of octocoral, extremely low levels of variation were observed between the mitogenomes of E. verrucosa and E. cavolini, suggesting a recent divergence of the species. Holaxonia-phylogenies were produced by exploiting partial contigs of mtMutS and complete mitochondrial protein-coding sequences. These phylogenies support the inclusion of Eunicella in the family Gorgonidae, in line with previous research. The confirmation of Eunicella spp. position within the octocoral phylogeny will allow for properly informed conservation efforts. The conservation of Eunicella spp. is especially important, as they are ecosystem engineers it is highly probable the conservation of Eunicella spp. will have secondary impact on other marine organisms that rely on Eunicella spp. for habitat or resources