Correction: Evolutionary Diversification of Banded Tube-Dwelling Anemones (Cnidaria; Ceriantharia; Isarachnanthus) in the Atlantic Ocean
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PROVIDER: S-EPMC4172771 | biostudies-literature | 2014 Jan
REPOSITORIES: biostudies-literature
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Project description:The use of molecular data for species delimitation in Anthozoa is still a very delicate issue. This is probably due to the low genetic variation found among the molecular markers (primarily mitochondrial) commonly used for Anthozoa. Ceriantharia is an anthozoan group that has not been tested for genetic divergence at the species level. Recently, all three Atlantic species described for the genus Isarachnanthus of Atlantic Ocean, were deemed synonyms based on morphological simmilarities of only one species: Isarachnanthus maderensis. Here, we aimed to verify whether genetic relationships (using COI, 16S, ITS1 and ITS2 molecular markers) confirmed morphological affinities among members of Isarachnanthus from different regions across the Atlantic Ocean. Results from four DNA markers were completely congruent and revealed that two different species exist in the Atlantic Ocean. The low identification success and substantial overlap between intra and interspecific COI distances render the Anthozoa unsuitable for DNA barcoding, which is not true for Ceriantharia. In addition, genetic divergence within and between Ceriantharia species is more similar to that found in Medusozoa (Hydrozoa and Scyphozoa) than Anthozoa and Porifera that have divergence rates similar to typical metazoans. The two genetic species could also be separated based on micromorphological characteristics of their cnidomes. Using a specimen of Isarachnanthus bandanensis from Pacific Ocean as an outgroup, it was possible to estimate the minimum date of divergence between the clades. The cladogenesis event that formed the species of the Atlantic Ocean is estimated to have occured around 8.5 million years ago (Miocene) and several possible speciation scenarios are discussed.
| S-EPMC3397977 | biostudies-literature
Project description:BackgroundCeriantharia is a subclass of the phylum Cnidaria, which comprises tube-dwelling marine invertebrates. This subclass is composed of three families, including Arachnactidae, with two known genera. Currently, the genus Arachnanthus has five valid species recorded from Australia, the Mediterranean Sea and both the Southern and Northern Pacific Ocean. However, at the moment, there is no record of organisms of this family from the South Atlantic Ocean. Besides that, the life cycle of any species of the genus Arachnanthus is known. The present study describes a new species of the genus Arachnanthus and its life cycle, based on specimens from Uruguay and South of Brazil.MethodsLarvae were collected by plankton net in Rio Grande-Brazil and the development and external morphology of these specimens were observed in the laboratory during two years, and subsequently described. Additionally, nine adult ceriantharians correspondent to the larvae from Rio Grande were collected in Uruguay and their external and internal anatomies, and cnidome were described.ResultsArachnanthus errans sp. nov. exhibited a free-swimming, short-lived cerinula larvae that spent short-time on the plankton. The larva developed into small and translucent polyps with a short actinopharynx, one pair of mesenteries attached to a siphonoglyph, and a medium first pair of metamesenteries. Further, the adult polyp displayed an unprecedented locomotion behavior in Ceriantharia that is first reported here, it can crawl under and in between the sediment.
| S-EPMC10211362 | biostudies-literature
Project description:Tube anemones, or cerianthids, are a phylogenetically informative group of cnidarians with complex life histories, including a pelagic larval stage and tube-dwelling adult stage, both known to utilize venom in stinging-cell rich tentacles. Cnidarians are an entirely venomous group that utilize their proteinaceous-dominated toxins to capture prey and defend against predators, in addition to several other ecological functions, including intraspecific interactions. At present there are no studies describing the venom for any species within cerianthids. Given their unique development, ecology, and distinct phylogenetic-placement within Cnidaria, our objective is to evaluate the venom-like gene diversity of four species of cerianthids from newly collected transcriptomic data. We identified 525 venom-like genes between all four species. The venom-gene profile for each species was dominated by enzymatic protein and peptide families, which is consistent with previous findings in other cnidarian venoms. However, we found few toxins that are typical of sea anemones and corals, and furthermore, three of the four species express toxin-like genes closely related to potent pore-forming toxins in box jellyfish. Our study is the first to provide a survey of the putative venom composition of cerianthids and contributes to our general understanding of the diversity of cnidarian toxins.
| S-EPMC7460484 | biostudies-literature
Project description:A new species of the genus Arachnanthus (Cnidaria: Ceriantharia), Arachnanthus lilith Stampar & El Didi, sp. n., is described. This species is widely distributed in the Red Sea, and recorded from 2-30 m depths. Arachnanthus lilith Stampar & El Didi, sp. n. is the fifth species of the genus and the first recorded from the Red Sea. The number of labial tentacle pseudocycles, arrangement of mesenteries, and distribution of acontioids allow the differentiation of the new species from other species of the genus.
| S-EPMC5904562 | biostudies-literature
Project description:Sequences and structural attributes of mitochondrial genomes have played a critical role in the clarification of relationships among Cnidaria, a key phylum of early-diverging animals. Among the major lineages of Cnidaria, Ceriantharia ("tube anemones") remains one of the most enigmatic in terms of its phylogenetic position. We sequenced the mitochondrial genomes of two ceriantharians to see whether the complete organellar genome would provide more support for the phylogenetic placement of Ceriantharia. For both Isarachnanthus nocturnus and Pachycerianthus magnus, the mitochondrial gene sequences could not be assembled into a single circular genome. Instead, our analyses suggest that both species have mitochondrial genomes consisting of multiple linear fragments. Linear mitogenomes are characteristic of members of Medusozoa, one of the major lineages of Cnidaria, but are unreported for Anthozoa, which includes the Ceriantharia. The inferred number of fragments and variation in gene order between species is much greater within Ceriantharia than among the lineages of Medusozoa. We identify origins of replication for each of the five putative chromosomes of the Isarachnanthus nocturnus mitogenome and for each of the eight putative chromosomes of the Pachycerianthus magnus mitogenome. At 80,923 bp, I. nocturnus now holds the record for the largest animal mitochondrial genome reported to date. The novelty of the mitogenomic structure in Ceriantharia highlights the distinctiveness of this lineage but, because it appears to be both unique to and diverse within Ceriantharia, it is uninformative about the phylogenetic position of Ceriantharia relative to other Anthozoa. The presence of tRNAMet and tRNATrp in both ceriantharian mitogenomes supports a closer relationship between Ceriantharia and Hexacorallia than between Ceriantharia and any other cnidarian lineage, but phylogenetic analysis of the genes contained in the mitogenomes suggests that Ceriantharia is sister to a clade containing Octocorallia + Hexacorallia indicating a possible suppression of tRNATrp in Octocorallia.
| S-EPMC6465557 | biostudies-literature
Project description:Subclass Ceriantharia is a well-defined and probably ancient group of marine benthic organisms renowned for their bilateral symmetry, which is reflected in the arrangement of tentacles and mesenteries. Four species of Ceriantharia have been reported in the Arctic, including Cerianthus lloydii Gosse, 1859, also known from the Northern Atlantic and Northern Pacific. The integrity of this species was questioned in the literature, so we performed a molecular study of C. lloydii from several geographically distant locations using 18S and COI genes. The phylogenetic reconstructions show that specimens of C. lloydii form a single group with high support (>0.98), subdivided into distinctive clades: (1) specimens from Northern Europe, the Black and Barents seas, and (2) specimens from the White, Kara, Laptev, and Bering seas and also the Canadian Arctic and the Labrador Sea available via the BOLD database. There are several BOLD COI sequences of Pachycerianthus borealis (Verrill, 1873), which form a third clade of the C. lloydii group, sister to the European and Arctic clades. Based on low similarity (COI 86-87%) between C. lloydii and the type species of the genus Cerianthus Delle Chiaje, 1841-C. membranaceus (Gmelin, 1791), we propose a new status for the genus Synarachnactis Carlgren, 1924, and a new family Synarachnactidae to accommodate C. lloydii.
| S-EPMC10525267 | biostudies-literature
Project description:This study reports on the fauna found in/on tubes of 10 species of Ceriantharia and discusses the characteristics of these occurrences, as well as the use of mollusc shells in ceriantharian tube construction. A total of 22 tubes of Ceriantharia from Argentina, Brazil, Japan, Norway, Portugal and the United States were analysed, revealing 58 species of marine invertebrates using them as alternative substrates. Based on a literature review and analyses of the sampled material, we report new occurrences for Photis sarae (Crustacea), Microgaza rotella (Mollusca), Brada sp., Dipolydora spp., Notocirrus spp., and Syllis garciai (Annelida). The use of mollusc shells in tube construction increases the tubes' structural resistance and strength. Ceriantharian tubes are suitable alternative substrates for the dwelling of numerous tubicolous and infaunal species that usually burrow into sediments or anchor on fixed or mobile habitats seeking shelter, thus playing a relevant role as local biodiversity hotspots.
| S-EPMC6962252 | biostudies-literature
Project description:The diversity of Ceriantharia is known from studies formally describing species from the late 18th Century onwards. However, no nomenclators including a list and discussion of all valid species have been produced since a list discussed by Carlgren in 1912. The present nomenclator presents a complete list of adult species of Ceriantharia of the World, including a discussion on each species. It includes the three families (Arachnactidae, Botrucnidiferidae, Cerianthidae) and the currently accepted 54 species based on their adult form. This study serves as a presentation of the "state-of-the-art" list of species of Ceriantharia, and includes a species identification key to support taxonomic identification. Additional in-depth species-by-species investigations for almost all cerianthid species is still needed, as the information available for most of these species is quite superficial.
| S-EPMC7394777 | biostudies-literature
Project description:The present study presents a revision of the genus Ceriantheomorphe Carlgren, 1931, including redescriptions of the two presently recognized species, Ceriantheomorphe ambonensis (Kwietniewski, 1898) and Ceriantheomorphe brasiliensis (Mello-Leitão, 1919), comb. nov., and a description of the new species Ceriantheomorphe adelita sp. nov.
| S-EPMC6746745 | biostudies-literature
Project description:BackgroundLike all cnidarians, the subclass Ceriantharia (Cnidaria, Anthozoa) is known for producing cnidocysts, which mainly serve for prey immobilization, predator defense, and locomotion.AimThe present study aimed to understand the variability of the cnidom, i.e., the inventory of all cnidocyst types, in the ceriantharians (tube anemones) Ceriantheomorphe brasiliensis (10 individuals) and Cerianthus sp. (seven individuals).MethodsIn each individual, 30 intact cnidocysts of each identified type were measured in the following parts of tube anemones: marginal tentacles (four from each individual), labial tentacles (four from each individual), column, actinopharynx and metamesenteries. Each of these structures was divided into three levels (high, middle, and low) and the cnidom was analyzed. Statistical descriptive parameters (mean, standard deviation, minimum and maximum) of the sizes of all types of cnidocysts were calculated. The normality of the data for cnidocyst length was assessed using a Shapiro-Wilk test (α = 0.05). Based on the acceptance or rejection of the normality, either linear models or generalized linear models were used to evaluate variations in cnidocyst lengths. The normality of the cnidocyst length was tested by Shapiro-Wilk, and due to its rejection, generalized linear mixed models were applied to test the cnidocyst lengths variations.ResultsThe analysis of Ceriantheomorphe brasiliensis revealed 23 categories of cnidocysts, thereby expanding the understanding of its cnidome. The cnidoms of Ceriantheomorphe brasiliensis and Cerianthus sp. presented intraspecific variations, both qualitatively and in the lengths of cnidocysts. The cnidoms of the two species studied also showed qualitative intra-individual variations between different levels (high, middle, low) within each structure of the tube anemone (tentacles, actinopharynx, column and metamesenteries). Some cnidocyst types, such as atrichs from the column of C. brasiliensis, presented a length gradient along the column, from larger lengths at the "low" level to smaller lengths at the "high" level.ConclusionsThe cnidom of a tube anemone could be better described if samples are taken at different levels of the structures, as observed in C. brasiliensis. In addition, we can conclude that the cnidocyst lengths of both C. brasiliensis and Cerianthus sp. present intraspecific variation, which is coincident with that observed in actiniarian sea anemones. Moreover, as main conclusion, this work also proved that individuals of tube anemone species could present qualitative intra-structure variations in both the cnidom and cnidocyst lengths. This characteristic appears as an exception in cnidom variations, and has so far not been recorded even in the most studied actiniarian sea anemones. Finally, the intra-structure cnidocyst variations could reveal different functions of the different levels of a particular body part of the organisms.
| S-EPMC10290448 | biostudies-literature