Development of an in vitro tissue culture system for hammer coral (Fimbriaphyllia ancora) ovaries

In vitro gonad culture systems have proven useful to investigate intrinsic mechanisms of sexual reproduction in animals. Here we describe development of an in vitro culture method for coral ovaries. Mesenterial tissues containing both ovaries and mesenterial filaments were microscopically isolated from the scleractinian coral, Fimbriaphyllia ancora, and culture conditions were optimized. M199 diluted 10× (10% M199, pH 8.1) and supplemented with 25 mM HEPES and the antibiotics, ampicillin, penicillin and streptomycin, supported oocyte survival and maintained the structural integrity of ovaries during short-term culture (~ 6 days). Addition of a commercial antibiotic–antimycotic solution (Anti–Anti) and fetal bovine serum adversely affected ovary maintenance and caused tissue disintegration. Characterization of cultured ovaries showed that there is no difference in cell proliferation of ovarian somatic cells between culture Days 1 and 6. Moreover, the presence of oogonia and expression of a major yolk protein, vitellogenin, were confirmed in ovaries cultured for 6 days. This system will be useful for studying effects of a wide range of substances on coral oogenesis.

Description of the second species of Synhalcurias Carlgren, 1914, Synhalcurias kahakui sp. nov. (Actiniaria: Actinernidae) with redescription of S. elegans (Wassilieff, 1908)

We describe a new sea anemone species, Synhalcurias kahakui sp. nov., from specimens collected off Otouto-jima and Amami-oshima islands in July 2016 and May 2019. respectively. These sea anemones were identified as belonging to family Actinernidae due to their many endocoelic perfect mesenteries and identified as belonging to the genus Synhalcurias Carlgren, 1914 because they have an oral disc without any developed lobes. Though this genus presently accommodates only one species, Synhalcurias elegans (Wassilieff, 1908), our specimens are smaller than the aforementioned species, have fewer mesenteries, lack nematocyst batteries on the column, and have two types of microbasic p-mastigophores on the mesenterial filaments. These specimens are described as Synhalcurias kahakui sp. nov. In view of the new species, the diagnosis of genus Synhalcurias is revised. In addition, we redescribe S. elegans based on newly specimens collected from Japan.

Influence of the Blue Coral Heliopora coerulea on Scleractinian Coral Larval Recruitment

The octocoral Heliopora coerulea has emerged as one of the most dominant reef-building corals in the Bolinao Reef Complex, northern Philippines. One of the possible mechanisms that may contribute to the success of H. coerulea over scleractinian corals is its ability to compete effectively for space on the reef by inhibiting the settlement of coral larvae in its immediate vicinity. To determine whether H. coerulea can indeed inhibit larval recruitment, settlement tiles were deployed inside H. coerulea aggregations or on hard substrate at a distance of about 2 to 3 meters away. After three months of deployment, only a single H. coerulea recruit was observed on tiles placed within aggregations whereas many different coral recruits were observed on tiles placed on substrate away from the blue coral. These results suggest that adult H. coerulea can inhibit the settlement of scleractinian larvae. This effect may be mediated by various mechanisms, such as the production of allelopathic compounds, deployment of mesenterial filaments, and sweeper tentacles. However, further studies are needed to determine the modes of competition that are used by the coral.

Aulactinia sinensis, a new species of sea anemone (Cnidaria: Anthozoa: Actiniaria) from Yellow Sea

Aulactinia sinensis, a new species of sea anemone collected from the intertidal zone of Qingdao, Yellow Sea, is describedand illustrated. This species is elongated, becoming plump distally, has circumscribed sphincter, and with 48 vertical rowsof verrucae in upper column, 48 pairs of mesenteries and 96 short tentacles. It is similar in shape to A. capitata Agassizin Verrill, 1864, but distinguished by its smaller basitrichs in tentacles and larger microbasic p-mastigophores in actinopharynx and mesenterial filaments.

Cnidocysts of Caryophylliidae and Dendrophylliidae (Cnidaria: Scleractinia): Taxonomic Distribution and Phylogenetic Implications

Caryophylliidae Dana, 1846 and Dendrophylliidae Gray, 1847 are families of widespread hard corals (order Scleractinia) composed mainly of azooxanthellate corals. A growing body of molecular data has provided new insights on hard-coral evolution, suggesting that many of the traditionally recognized families are not monophyletic. The morphology of the skeletal parts has been the only source of evidence for the taxonomy of the group for many years. Soft anatomy has been less explored, and recently, with the increased use of molecular evidence, anatomical studies have decreased in importance. As a result, for many taxa, we know little or nothing about variation in soft tissue morphology and their use for systematics has never been explored. In this study we examined the cnidocysts of two species of caryophylliids and of four dendrophylliids, and synthesized previous studies on the subject. We performed a morphological phylogenetic analysis, based on eight informative characters, which includes eight species of dendrophylliids and 11 caryophylliid taxa. Five taxa belonging to the families Poritidae, Flabellidae, and Fungiacyathidae were also scored for these morphological characters. The aims were to investigate the diversity of cnidocysts in members of the two families and test the monophyly of Dendrophylliidae. The data support a dendrophylliid clade and indicate the presence of b-rhabdoids (1) in mesenterial filaments as a synapomorphy of the family. The taxonomic distribution of two other characters contradicts the clade (Dendrophylliidae + Poritidae) suggested by molecular analyses. Our results reinforce the relevance of soft tissue studies in hard-corals to reconstructing their phylogeny.

Actinia ebhayiensis sp. nov., a new species of sea anemone (Anthozoa: Actiniaria: Actiniidae) from South Africa

In this work we describe Actinia ebhayiensis sp. nov. from South Africa. The species is externally similar to the type species of the genus, Actinia equina, from which it can be distinguished by nematocyst and allozyme data. Actinia ebhayiensis has a smooth, red column, with well-delimited parapet leading to a deep fosse where conspicuous blue acrorhagi can be found. Tentacles and oral disc are crimson red, and the pedal disc has a lighter pink colour. The microbasic p-mastigophores and b-mastigophores of the mesenterial filaments of the new species are significantly smaller than those of A. equina. Actinia ebhayiensis can also be clearly distinguished from other species of the genus in nematocyst measurements, genetic data and muscle morphology.

Composition, biometry and statistical relationships between the cnidom and body size in the sea anemone Oulactis muscosa (Cnidaria: Actiniaria)

This study analyses the possible relationships between body size and length of cnidae from different tissues of the sea anemone Oulactis muscosa. We describe the cnidom, providing new qualitative and quantitative data. Our description adds spirocysts for tentacles and acrorhagi, and is more precise about the ranges and types of basitrichs, microbasic b-mastigophores, and holotrichs. We distinguish two types of holotrichs in the acrorhagi, and differentiate between microbasic b-mastigophores and basitrichs in the actinopharynx and mesenterial filaments. A relationship between cnida length and body weight was not demonstrated. The results are based on a complete account of cnida types from all tissues, and considering the great number of capsules measured (5400) and the modern statistical tools employed, we think that a normal distribution of cnida lengths is uncommon, perhaps refuted. This finding is very important when a quantitative analysis of cnidae is necessary and an adequate statistical tool must be used. We have shown that generalized linear models are an alternative and therefore analyses can be done with parametric methods despite the non-normal distribution of cnida size. The use of these statistical tools should be generalized since appropriate package for analyses (like the R package) are available from the web and the obtained results are robust and powerful.