Phylogenetic relationships within the tropical soft coral genera Sarcophyton and Lobophytum (Anthozoa, Octocorallia)

Abstract

Abstract. The alcyonacean soft coral genera Sarcophyton and Lobophytum are conspicuous, ecologically important members of shallow reef communities throughout the Indo-West Pacific. Study of their ecology is, however, hindered by incomplete knowledge of their taxonomy: most species cannot be identified in the field and the two genera cannot always be distinguished reliably. We used a 735-bp fragment of the octocoral-specific mitochondrial protein-coding gene msh1 to construct a phylogeny for 92 specimens identified to 19 species of Lobophytum and 16 species of Sarcophyton. All phylogenetic methods used recovered a tree with three strongly supported clades. One clade included only morphologically typical Sarcophyton species with a stalk distinct from the polypary, poorly formed club-shaped sclerites in the colony surface, and large spindles in the interior of the stalk. A second clade included only morphologically typical Lobophytum colonies with lobes and ridges on the colony surface, poorly formed clubs in the colony surface, and interior sclerites consisting of oval forms with regular girdles of ornamental warts. The third distinct clade included a mix of Sarcophyton and Lobophytum nominal species with intermediate morphologies. Most of the species in this mixed clade had a polypary that was not distinct from the stalk, and the sclerites in the colony surface were clubs with well-defined heads. Within the Sarcophyton clade, specimens identified as Sarcophyton glaucum belonged to six very distinct genetic sub-clades, suggesting that this morphologically heterogeneous species is actually a cryptic species complex. Our results highlight the need for a complete taxonomic revision of these genera, using molecular data to help confirm species boundaries as well as to guide higher taxonomic decisions.

Bacterial communities from corals cultured ex situ remain stable under different light regimes — Relevance for in toto aquaculture

“…As the taxonomic status of S. glaucum is still far from being consensual (McFadden et al, 2006;Steinke et al, 2012), the corals used on this experiment were classified as Sarcophyton cf. glaucum.…”

A second, cryptic species of the soft coral genus Incrustatus (Anthozoa: Octocorallia: Clavulariidae) from Tierra del Fuego, Argentina, revealed by DNA barcoding

“…Although other mitochondrial gene regions, most notably the octocoral-specific mitochondrial mutS homolog (mtMutS, previously known as msh1), appear to be somewhat better barcodes for octocorals than the widely used cytochrome oxidase I (COI), both mitochondrial markers still only discriminate about 70-80 % of congeneric species (McFadden et al 2011). Despite their inability to separate some closely related species, however, the use of DNA barcodes in biodiversity surveys has already proven useful for detecting cryptic species in octocorals, taxa for which there is often a paucity of morphological characters available for taxonomy (McFadden et al 2006(McFadden et al , 2011.…”

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“…In contrast, the animal collected from a different place in the GBR and studied by Coll et al [13] preyed upon S. trocheliophorum , which is according to McFaddens and co-workers phylogenetic research [53] found in the different clade from the S. glaucum species complex (see Fig. 12).…”

“…The phylogenetic analysis by McFadden et al clearly showed that the relationship and systematics of the soft coral genus Sarcophyton is not resolved (see Fig. 12) [53]. S. glaucum seems to be a species complex with at least 6 different clades.…”

“…S. glaucum seems to be a species complex with at least 6 different clades. Furthermore one of the former investigated species ( S. subviride , compound 3 ) is considered to be synonymous with S. glaucum [53]. A retrospective assignment of the investigated S. glaucum specimens and the identified metabolites mentioned above is not possible.…”