Plumapathes Opresko 2001

“Plumapathes gen. nov.

(figs 13-14)

Antipathes Pallas, 1766: 205 (in part); van Pesch, 1914: 85 (subgenus Aphanipathes, in part); Opresko, 1974: 82 (in part).

Aphanipathes Brook, 1889: 121 (in part).

Diagnosis.— Corallum sparsely to densely branched and tending to be planar. Stem and branches pinnulate. Primary pinnules simple, relatively uniform in size, and not subpinnulate; arranged in two, very regular bilateral rows; pinnules in each row alternating with those in opposite row.

Type species— Antipathes pennacea Pallas, 1766.

Type material.— Pallas, 1766, based this species on a specimen that he reported came from "Oceanus Indicus" and which he considered to be identical to Rumphius's "Erica marina crassa". Pallas' specimen has not been located. Because of the limitations in the original description, and because of the range of morphological variability that has been reported for this species (see Opresko, 1974), the establishment of a neotype is necessary to clearly define the species.

Neotype.— RMNH Coel.6801, Indian Ocean, Madagascar, Europa Island, 23.xii.1965, P. Vasseur, depth not reported.

Description of the neotype.— The specimen is 12.5 cm high and about 11 cm in width (fig. 13). A basal plate is not present and the specimen may be only a branch from a larger colony. The diameter of the large, stem-like branch is about 2.4 mm at its lower end. The corallum is branched to the third order; mostly in one plane. The stem and branches bear simple filiform pinnules. The largest pinnules are mostly 3-4 cm in length (maximum about 5 cm) and about 0.2 mm in diameter (excluding spines) near the point of insertion on the branch or stem. The pinnules are arranged in two lateral rows with members of each row spaced 1.6-2.0 mm apart. There are six to nine pinnules per centimeter in each row and 13-17 per centimeter for both rows. The spines (fig. 14) are conical, with an acute to rounded apex. Over most of the length of the pinnules the polypar spines are 0.16-0.18 mm tall, and the abpolypar spines are slightly smaller. Near the tip of the pinnules the spines decrease in size to 0.03-0.05 mm, and near the base they are up to 0.24 mm tall. The pinnular spines are arranged in five to six longitudinal rows (lateral view, excluding rows only partially visible), usually with about six spines per millimeter in each row (mutual distance mostly 0.18-0.22 mm). On the branches and stem the spines become more needle-like, but are similar in size to the largest pinnular spines, about 0.24 mm. With increasing diameter of the axis, the spines become more densely and more irregularly arranged. On the stem there are 24 or more very irregular rows visible in lateral view.

The polyps are arranged in a single series on the lateral or upper side of pinnules, and on one side of the branches and stem. Consequently, there is a distinct polypar and abpolypar side to the corallum. The polyps measure 0.7-0.8 mm in transverse diameter with a small interpolypar space such that there are 10-14 polyps per centimeter on the pinnules. In the preserved state the tentacles measure up to 0.2 mm long, and have a rounded blunt tip.

Species Assigned to Plumapathes.— At present only one other nominal species, Antipathes fernandezi Pourtalès, 1874, can be referred to this genus. The pinnules of P. fernandezi are not as uniform in size nor are they as regular in arrangement as those in P. pennacea.

Although specimens referred to A. pennacea are common in the western Atlantic (Caribbean region; Opresko, 1974) and also known from the south Atlantic (St. Helena; Brook, 1889; Opresko, 1974), the species has only rarely been reported from the Indo-Pacific, the type locality, van Pesch, 1914, however, described several specimens from the Philippines under the name Antipathes pennacea. These differ from neotype particularly in the maximum size of the axial spines (0.11 mm vs. 0.24 mm). Furthermore, the St. Helena specimens differ from both the Indo-Pacifc specimens of van Pesch and the western Atlantic material in both the size of the spines (up to 0.32 mm) and in the density of the polyps (see Opresko, 1974, for further discussion). Thus, it is quite likely that more than one species is currently included under the name P. pennacea.

Remarks.— The genus Plumapathes shows affinities to some species of Antipathella, particularly those species in which the pinnules are arranged bilaterally and mostly in two rows. In Plumapathes, however, the pinnules are more uniform in both size and arrangement than in any species of Antipathella.

Etymology.— The genus name is derived from "pluma" Latin for feather, in reference to the feather-like appearance of the branches, and the commonly used suffix "pathes".

Distribution.— Specimens identified as P. pennacea have been reported from the Indo-Pacific, southern Atlantic, and western Atlantic. Plumapathes fernandezi is known only from the eastern Pacific.”

(Opresko, 2001)

Plumapathes is a genus of black coral in the order Antipatharia.