RESUMEN
Currently composed of only one order and two families, the class Homoscleromorpha has undergone significant changes in its systematics over the past 20 years. We combined morphological, cytological and molecular (CO1) data to describe three new aspiculate Homoscleromorpha, two Plakinidae and one Oscarellidae. These three sponges live in the dark submarine caves of the Lesser Antilles (Caribbean Sea). Aspiculortis gen. nov. is part of a clade including spiculate Plakortis species. Aspiculortis garifuna gen. nov. sp. nov. is characterized by an original pseudo criblate smooth surface, with a network of translucent canals ending in prominent oscula, and by one type of vacuolar cell concentrated in the ectosome. Aspiculophora papillata sp. nov. is characterized by a papillate surface, a morphological trait that is recorded for the first time among Homoscleromorpha, and one abundant type of vacuolar cell randomly distributed in the mesohyl. Oscarella minka sp. nov. is characterized by a smooth surface and two types of vacuolar cells, one principally found in the ectosome, and a second type which is randomly distributed and which harbors original inclusions. These three new Homoscleromorpha present an abundant microbial community in their mesohyl. After this work, the skeleton-less representatives of this sponge class include four species of Plakinidae belonging to three different genera, and all Oscarellidae described so far. The putative absence of skeleton underlines the need of more cytological descriptions of Plakinidae representatives.
Asunto(s)
Plakortis , Poríferos , Animales , Filogenia , Indias Occidentales , Región del Caribe , CuevasRESUMEN
Knowledge of homoscleromorph sponge biodiversity has greatly improved during the last decade thanks to the increasing use of integrative taxonomy and extensive exploration of remote ecosystems. Indeed, recently described species have mostly been small sponges living in dark and near-impenetrable habitats. This work integrates morphological, cytological, ecological and molecular data to describe a new species belonging to the Plakina genus. Plakina doudou sp. nov. was found first during close inspection of photographs taken previously in a submarine cave on Martinique Island, where several new species had already been revealed. The new species lives in syntopy with P. arletensis. It is thinly encrusting, whitish in vivo, and its skeleton harbors a unique composition of diods, triods, monolophose triods and monolophose, dilophose and trilophose calthrops. Sequencing of a portion of the mitochondrial gene cox-1 indicates that the new species belongs to a well-supported clade containing the Mediterranean P. crypta and P. trilopha. However, at the time of publication of this work, we have not yet managed to identify synapomorphies that would support the different clades of Plakina. This genus includes a total of 39 species to date, of which 10 have been recorded in the Western Tropical Atlantic, and 4 in Caribbean submarine caves.
Asunto(s)
Cuevas , Poríferos , Animales , Ecosistema , MartinicaRESUMEN
Sponges harbor characteristic microbiomes derived from symbiotic relationships shaping their lifestyle and survival. Haliclona fulva is encrusting marine sponge species dwelling in coralligenous accretions or semidark caves of the Mediterranean Sea and the near Atlantic Ocean. In this work, we characterized the abundance and core microbial community composition found in specimens of H. fulva by means of electron microscopy and 16S amplicon Illumina sequencing. We provide evidence of its low microbial abundance (LMA) nature. We found that the H. fulva core microbiome is dominated by sequences belonging to the orders Nitrosomonadales and Cenarchaeales. Seventy percent of the reads assigned to these phylotypes grouped in a very small number of high-frequency operational taxonomic units, representing niche-specific species Cenarchaeum symbiosum and uncultured Betaproteobacteria HF1, a new eubacterial ribotype variant found in H. fulva. The microbial composition of H. fulva is quite distinct from those reported in sponge species of the same Haliclona genus. We also detected evidence of an excretion/capturing loop between these abundant microorganisms and planktonic microbes by analyzing shifts in seawater planktonic microbial content exposed to healthy sponge specimens maintained in aquaria. Our results suggest that horizontal transmission is very likely the main mechanism for symbionts' acquisition by H. fulva. So far, this is the first shallow water sponge species harboring such a specific and predominant assemblage composed of these eubacterial and archaeal ribotypes. Our data suggests that this symbiotic relationship is very stable over time, indicating that the identified core microbial symbionts may play key roles in the holobiont functioning.
Asunto(s)
Archaea/clasificación , Betaproteobacteria/clasificación , Haliclona/microbiología , Microbiota , Agua de Mar/microbiología , Simbiosis , Animales , Archaea/genética , Archaea/aislamiento & purificación , Archaea/fisiología , Bacterias , Betaproteobacteria/genética , Betaproteobacteria/aislamiento & purificación , Betaproteobacteria/fisiología , ADN de Archaea/análisis , ADN Bacteriano/análisis , Francia , Mar Mediterráneo , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Especificidad de la Especie , Microbiología del AguaRESUMEN
Calcareous sponges from the Lesser Antilles were recently inventoried and several specimens morphologically resembling species of the genus Ascoleucetta were collected. Morphological and molecular (C-LSU and ITS) analyses indicated that these specimens from the Lesser Antilles constituted a new genus. They lack the conspicuous and very characteristic ornamentation of the inhalant apertures found in two out of three species of Ascoleucetta, including the type species A. compressa. In the molecular analyses, the specimens clustered as an independent lineage, distant from the clade of A. compressa. Based on these results, we decided to erect a new genus, Bidderia gen. nov., whose type species is Bidderia bicolora gen. nov. sp. nov. Considering this new discovery, we are proposing to transfer the species A. amitsba to the genus Bidderia gen. nov. and to rediagnose Ascoleucetta.
Asunto(s)
Filogenia , Poríferos , Animales , Región del Caribe , Indias OccidentalesRESUMEN
The sponge class Homoscleromorpha is a key model for the evolutionary biology of the Metazoa but its diversity remains poorly known. Here we describe six new species of the homoscleromorph family Plakinidae found in shaded habitats (submarine caves, tunnels and overhangs) of New Caledonia and Marquesas Islands, Central-Western Pacific. The new species belong to four genera: Corticium (Corticium vaceleti sp. nov.), Plakina (Plakina finispinata sp. nov.), Plakinastrella (Plakinastrella osculifera sp. nov., Plakinastrella nicoleae sp. nov. and Plakinastrella pseudolopha sp. nov.), and Plakortis (Plakortis ruetzleri sp. nov.). Plakinastrella pseudolopha sp. nov. has a novel spicule type called here 'pseudolophose spicules'. The diversity of Homoscleromorpha is raised to 50 species in the Pacific Ocean and 120 spp. worldwide.
Asunto(s)
Filogenia , Poríferos , Animales , Cuevas , Nueva Caledonia , Océano Pacífico , PlakortisRESUMEN
Calcareous sponges of the subclass Calcinea from Martinique (Caribbean Sea) are presented under an integrative perspective (morphology and DNA: ITS and C-LSU). Eleven species of six genera have been found in Martinique, three of them being new to science: Borojevia crystallina sp. nov., Clathrina delicata sp. nov., and Ernstia adunca sp. nov. Among these new records, four species were previously known from other Caribbean localities: Arturia vansoesti, Clathrina insularis, C. mutabilis, and Leucaltis clathria. Two species previously known in Brazilian waters are reported for the first time in the Caribbean Sea: Arturia alcatraziensis and C. cf. cylindractina. Finally, the occurrence of C. aurea and Leucetta floridana in Martinique is confirmed. The two molecular markers (ITS and C-LSU) and the morphological characters considered (e.g. body shape, aquiferous system and spicules) provided congruent classifications what tend to confirm their reliability for the taxonomy of Clathrinida. After the present work, a total of 17 species of Calcarea are recognised for Martinique. We discuss three types of distribution patterns (Endemic, Caribbean-Brazil, and Amphi-Atlantic), Martinique likely playing an important role as stepping stone to garantee connectivity among populations of Calcinea in the Atlantic.
Asunto(s)
Poríferos , Animales , Biodiversidad , Brasil , Región del Caribe , MartinicaRESUMEN
Although sponges are important components of benthic ecosystems of the Caribbean Sea, their diversity remained poorly investigated in the Lesser Antilles. By organizing a training course in Martinique, we wanted both to promote taxonomy and to provide a first inventory of the sponge diversity on this island. The course was like a naturalist expedition, with a field laboratory and a classroom nearby. Early-career scientists and environmental managers were trained in sponge taxonomy. We gathered unpublished data and conducted an inventory at 13 coastal sites. We explored only shallow water habitats (0-30 m), such as mangroves, reefs or rocky bottoms and underwater caves. According to this study, the sponge fauna of Martinique is currently represented by a minimum of 191 species, 134 of which we could assign species names. One third of the remaining non-identified sponge species we consider to be new to science. Martinique appears very remarkable because of its littoral marine fauna harboring sponge aggregations with high biomass and species diversity dominating over coral species. In mangroves, sponges cover about 10% of the surface of subtidal roots. Several submarine caves are true reservoirs of hidden and insufficiently described sponge diversity. Thanks to this new collaborative effort, the Eastern Caribbean has gained a significant increase of knowledge, with sponge diversity of this area potentially representing 40% of the total in the Caribbean Sea. We thus demonstrated the importance of developing exploratory and educational research in areas historically devoid of biodiversity inventories and systematics studies. Finally, we believe in the necessity to consider not only the number of species but their distribution in space to evaluate their putative contribution to ecosystem services and our willingness to preserve them.
Asunto(s)
Poríferos/clasificación , Animales , Biodiversidad , Clasificación , Ecología/educación , Ecosistema , Martinica , Poríferos/anatomía & histología , Zoología/educaciónRESUMEN
A thin fiber-less sponge from Caribbean reefs (Bocas del Toro, Panama) with close genetic affinities (based on 18S and 28S nuclear ribosomal RNA gene sequences) to large fan-shaped fiber-bearing sponges (Ianthella and Anomoianthella) from the Indo-Pacific Ocean is here presented. We describe its overall external morphology, histological features, and ultrastructure. Its genetic distance from the only previously known fiber-less verongid genus, Hexadella, prompted the need to erect a new genus to classify this species. This novel species constitutes the first record for a member of the family Ianthellidae in the Caribbean. The characterization of the family Ianthellidae (sensu Cook and Bergquist, 2000) is here modified by: i) highlighting the cavernous nature of the choanosome, with many lacunae and channels reported for all genera included in the family; ii) extending the family distribution to the Caribbean; and iii) adding a fourth genus to the group of verongids with eurypylous chambers. The possession of a cellularized cortex (10-300 µm in thickness) is here proposed as a potential synapomorphic character of the Ianthella-Anomoianthella-Vansoestia clade. The main issues regarding the suprageneric classification of verongids are discussed.