Porphyrophyton, Mcfadden & Van Ofwegen, 2017

Mcfadden, Catherine S. & Van Ofwegen, Leen P., 2017, Revisionary systematics of the endemic soft coral fauna (Octocorallia: Alcyonacea: Alcyoniina) of the Agulhas Bioregion, South Africa, Zootaxa 4363 (4), pp. 451-488 : 475

Porphyrophyton , n. gen.

Type species. Alcyonium distinctum Williams, 1988 by original designation

Diagnosis. Colonies lobate, lobes arising from a short, distinct stalk. Polyps retractile. Sclerites present in stalk surface only, absent from polyps, polyparium surface and colony interior. Sclerites are spheroids or radiates. Colonies vividly colored in life as a result of alcohol-soluble pigments. Sclerites colorless.

Etymology. From the Greek porphyros meaning purple, and phyton, a creature (plant or animal), in recognition of the vivid purple color of the type species. Gender: neutral.

Remarks. Phylogenetic analyses unite Porphyrophyton distinctum n. comb. in a clade with other soft corals endemic to South Africa ( Fig. 1 ), including other species formerly placed in Alcyonium . Unlike Alcyonium sensu stricto (McFadden & Ofwegen 2013), Porphyrophyton n. gen. completely lacks sclerites in the polyps, surface of the polyparium and interior coenenchyme, and has only spheroids and radiates in the surface of the short stalk. Like most other members of Leptophytidae n. fam., its bright purple color in life is the result of alcohol-soluble pigments rather than permanently pigmented sclerites. The complete lack of sclerites in the polyps, the growth form with lobes arising from a short stalk, and the spheroidal sclerites in the stalk surface are all characters that distinguish Porphyrophyton n. gen. from the other genera included in Leptophytidae n. fam. Morphologically, Porphyrophyton n. gen. most closely resembles some species of Parasphaerasclera (Parasphaerascleridae) that likewise have no sclerites in the polyps and have only spheroids or radiates in the colony surface. That genus, however, has permanently pigmented sclerites as well as sclerites in the colony interior (McFadden & Ofwegen 2013), and is phylogenetically distant from Leptophytidae n. fam. ( Fig. 1 ).

Figures

FIGURE 1. Maximum likelihood phylogeny of Octocorallia based on combined, partitioned analysis of 28S rDNA, COI and 16S mtDNA.South African species and clades are identified in blue. Filled circles indicate nodes with>70% bootstrap support and Bayesian posterior probabilities>0.95 (shown for South African clades only). Strongly supported clades (bootstrap 70%) with no South African members have been collapsed to facilitate readability. Phylogenetic position of Protodendron repens indicated with *.