Restructuring the Traditional Suborders in the Order Scleractinia Based on Embryogenetic Morphological Characteristics

Okubo, Nami

doi:10.2108/zs150094

Cited by 14 publications

(4 citation statements)

References 34 publications

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“…Recent advancements in molecular phylogenetic construction of the evolutionary history of scleractinian corals echo this proposal along with proposed major deviations from traditional classification schemes. The first deviation was the discovery of two major lineages within the order, now referred to as the robust and complex clades ( Romano & Palumbi, 1996 ; Romano & Palumbi, 1997 ; Romano & Cairns, 2000 ; Chen, Wallace & Wolstenholme, 2002 ; Fukami et al, 2008 ; Huang et al, 2009 ; Kitahara et al, 2010 ; Okubo, 2016 ). The second deviation showed that paraphyly was found in 11 traditional families of the Scleractinia ( Fukami et al, 2008 ; Huang et al, 2009 ; Huang et al, 2011 ; Huang et al, 2014a ; Huang et al, 2014b ; Arrigoni et al, 2012 ).…”

Section: Introductionmentioning

confidence: 99%

Resurrecting a subgenus to genus: molecular phylogeny ofEuphylliaandFimbriaphyllia(order Scleractinia; family Euphyllidae; clade V)

Luzon

Lin

Ablan-Lagman

et al. 2017

PeerJ

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BackgroundThe corallum is crucial in building coral reefs and in diagnosing systematic relationships in the order Scleractinia. However, molecular phylogenetic analyses revealed a paraphyly in a majority of traditional families and genera among Scleractinia showing that other biological attributes of the coral, such as polyp morphology and reproductive traits, are underutilized. Among scleractinian genera, the Euphyllia, with nine nominal species in the Indo-Pacific region, is one of the groups that await phylogenetic resolution. Multiple genetic markers were used to construct the phylogeny of six Euphyllia species, namely E. ancora, E. divisa, E. glabrescens, E. paraancora, E. paradivisa, and E. yaeyamaensis. The phylogeny guided the inferences on the contributions of the colony structure, polyp morphology, and life history traits to the systematics of the largest genus in Euphyllidae (clade V) and, by extension, to the rest of clade V.ResultsAnalyses of cytochrome oxidase 1 (cox1), cytochrome b (cytb), and β-tubulin genes of 36 colonies representing Euphyllia and a confamilial species, Galaxea fascicularis, reveal two distinct groups in the Euphyllia that originated from different ancestors. Euphyllia glabrescens formed a separate group. Euphyllia ancora, E. divisa, E. paraancora, E. paradivisa, and E. yaeyamaensis clustered together and diverged from the same ancestor as G. fascicularis. The 3′-end of the cox1 gene of Euphyllia was able to distinguish morphospecies.DiscussionSpecies of Euphyllia were traditionally classified into two subgenera, Euphyllia and Fimbriaphyllia, which represented a dichotomy on colony structure. The paraphyletic groups retained the original members of the subgenera providing a strong basis for recognizing Fimbriaphyllia as a genus. However, colony structure was found to be a convergent trait between Euphyllia and Fimbriaphyllia, while polyp shape and length, sexuality, and reproductive mode defined the dichotomy better. Species in a genus are distinguished by combining polyp morphology and colony form. The cluster of E. glabrescens of the Euphyllia group is a hermaphroditic brooder with long, tubular tentacles with knob-like tips, and a phaceloid colony structure. The Fimbriaphyllia group, with F. paraancora, F. paradivisa, F. ancora, F. divisa, and F. yaeyamaensis, are gonochoric broadcast spawners with short polyps, mixed types of tentacle shapes, and a phaceloid or flabello-meandroid skeleton. Soft-tissue morphology of G. fascicularis and Ctenella chagius were found to be consistent with the dichotomy.ConclusionsThe paraphyly of the original members of the previous subgenera justify recognizing Fimbriaphyllia as a genus. The integrated approach demonstrates that combining polyp features, reproductive traits, and skeletal morphology is of high systematic value not just to Euphyllia and Fimbriaphyllia but also to clade V; thus, laying the groundwork for resolving the phylogeny of clade V.

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Section: Introductionmentioning

confidence: 99%

Resurrecting a subgenus to genus: molecular phylogeny ofEuphylliaandFimbriaphyllia(order Scleractinia; family Euphyllidae; clade V)

Luzon

Lin

Ablan-Lagman

et al. 2017

PeerJ

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“…Therefore, it is unlikely the cocoon is a remnant part of the bundle mucous membrane. Recently, a hyaline layer (which assists in cellular orientation of embryos during development) has been proposed for one species of coral Tubastraea coccinea , but this has yet been identified in other species [ 60 ]. At these very early stages of development, it is unlikely mucous-producing cells have been formed, and in Acropora millepora these tend to increase in numbers typically after ~170 h [ 26 ].…”

Section: Discussionmentioning

confidence: 99%

Mucous Secretion and Cilia Beating Defend Developing Coral Larvae from Suspended Sediments

et al. 2016

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Suspended sediments produced from dredging activities, or added to the sediment budget via river runoff, are a concern for marine resource managers. Understanding the impact of suspended sediments on critical life history stages of keystone species like corals is fundamental to effective management of coastlines and reefs. Coral embryos (Acropora tenuis and A. millepora) and larvae (A. tenuis, A. millepora and Pocillopora acuta) were subjected to a range of suspended sediment concentrations of different sediment types (siliciclastic and carbonate) to assess concentration-response relationships on ecologically relevant endpoints, including survivorship and ability to metamorphose. Embryos were subjected to short (12 h) suspended sediment exposures from ages of 3–12 hours old or a long (30 h) exposure at 6 hours old. Neither the survivorship nor metamorphosis function of embryos were significantly affected by realistic sediment exposures to ~1000 mg L-1. However, some embryos exhibited a previously undescribed response to dynamically suspended sediments, which saw 10% of the embryos form negatively buoyant cocoons at siliciclastic suspended sediment concentrations ≥35 mg L-1. Scanning electron and optical microscopy confirmed the presence of a coating on these embryos, possibly mucus with incorporated sediment particles. Cocoon formation was common in embryos but not in larvae, and occurred more often after exposure to siliciclastic rather than carbonate sediments. Once transferred into sediment-free seawater, functional ~36-h-old embryos began emerging from the cocoons, coinciding with cilia development. Ciliated (> 36-h-old) larvae exposed to suspended sediments for 60 h were also observed to secrete mucus and were similarly unaffected by suspended sediment concentrations to ~800 mg L-1. This study provides evidence that mucous secretion and cilia beating effectively protect coral embryos and larvae from suspended sediment and that these mechanisms may enhance their chances of successful recruitment.

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“…An interesting aspect common to all specialist clades is the association with corals belonging only to the Complex clade, whereas generalists are hosted indiscriminately by Coral Reefs both Complex and Robust corals. At the moment, it is difficult to suggest possible explanations for this pattern relying on differences between Complex and Robust clades, since the two scleractinian groups are mostly based on molecular and embryogenetic data rather than on morphological, biological, or ecological criteria (Romano and Palumbi 1996;Okubo et al 2013Okubo et al , 2016Okubo 2016).…”

Section: Relationships Among Zanclea Clades and Their Scleractinian Hmentioning

confidence: 99%

Evolution and biogeography of the Zanclea-Scleractinia symbiosis

et al. 2020

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Scleractinian corals provide habitats for a broad variety of cryptofauna, which in turn may contribute to the overall functioning of coral symbiomes. Among these invertebrates, hydrozoans belonging to the genus Zanclea represent an increasingly known and ecologically important group of coral symbionts. In this study, we analysed 321 Zanclea colonies associated with 31 coral genera collected from 11 localities across the Indo-Pacific and Caribbean regions, and used a multi-disciplinary approach to shed light on the evolution and biogeography of the group. Overall, we found high genetic diversity of hydrozoans that spans nine clades corresponding to cryptic or pseudo-cryptic species. All but two clades are associated with one or two coral genera belonging to the Complex clade, whereas the remaining ones are generalists associated with both Complex and Robust corals. Despite the observed specificity patterns, no congruence between Zanclea and coral phylogenies was observed, suggesting a lack of coevolutionary events. Most Zanclea clades have a wide distribution across the Indo-Pacific, including a generalist group extending also into the Caribbean, while two host-specific clades are possibly found exclusively in the Red Sea, confirming the importance of this peripheral region as an endemicity hotspot. Ancestral state reconstruction suggests that the most recent common ancestor of all extant coral-associated Zanclea was a specialist species with a perisarc, occurring in what is now known as the Indo-Pacific. Ultimately, a mixture of geography- and host-related diversification processes is likely responsible for the observed enigmatic phylogenetic structure of coral-associated Zanclea.

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Restructuring the Traditional Suborders in the Order Scleractinia Based on Embryogenetic Morphological Characteristics

Cited by 14 publications

References 34 publications

Resurrecting a subgenus to genus: molecular phylogeny ofEuphylliaandFimbriaphyllia(order Scleractinia; family Euphyllidae; clade V)

Resurrecting a subgenus to genus: molecular phylogeny ofEuphylliaandFimbriaphyllia(order Scleractinia; family Euphyllidae; clade V)

Mucous Secretion and Cilia Beating Defend Developing Coral Larvae from Suspended Sediments

Evolution and biogeography of the Zanclea-Scleractinia symbiosis

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