Muricea mortensenii Hickson, 1928

Breedy, Odalisca & Guzman, Hector M., 2016, A revision of the genus Muricea Lamouroux, 1821 (Anthozoa, Octocorallia) in the eastern Pacific. Part II, ZooKeys 581, pp. 1-69 : 31-35

Taxon classification Animalia Alcyonacea Plexauridae

Muricea mortensenii Hickson, 1928 Figures 22, 23

Muricea mortensenii Hickson, 1928: 369-371; Stiasny 1943: 69-72.

Material.

Holotype. MZUC ANT 106, ethanol preserved, Rey Island, Pearl Islands, Panamá, T. Mortensen, 27.4 m, 26 January 1916. Schizotype RMNH Coel 6553.

Description

(see also Hickson 1928). The holotype is a flabelliform colony 15 cm tall and 18 cm wide (Fig. 22A). A short stem, 6 mm in diameter, arises from an irregular holdfast, 22 mm in diameter, which bears a few scattered polyps. The stem divides into numerous branches, each about 3 mm in diameter; they subdivide in an irregular manner producing branchlets, 2-3 mm in diameter, closely placed, mostly 1-2 mm apart, and at angles 30-45°. Branchlets are very numerous and overlap on the surface of the fan, but do not anastomose. Branches subdivide up to four times. Unbranched terminal ends are mostly 2-4 mm long. Calyces are elongated, 0.7-1.0 mm long from the base to the tip, with lower borders slightly curved inwards. Calyces are numerous, not imbricate, placed all around the branches, very close together, about 18-20 calyces/cm around the branches, 10-15/cm around the branchlets, (Fig. 22B). Polyps are whitish preserved in ethanol. All sclerites are whitish to colourless (Fig. 22C). Coenenchyme is very thin, composed of warty spindles, 0.35-0.7 mm long and 0.07-0.12 mm wide, of diverse shapes, straight, curved or irregular with one side curved and the other straight (Fig. 23A). Leaf spindles and modified forms 0.18-0.53 mm long and 0.068-0.13 mm wide, with long lateral sharp spines, are also present (Fig. 23B). The axial sheath is composed of immature forms, spindles and capstans, 0.08-0.13 mm long and 0.03-0.05 mm wide (Fig. 23C). Anthocodial sclerites are warty rods, 0.11-0.21 mm long and 0.02-0.08 mm wide, some with bifurcated ends (Fig. 23D).

Colour of the colony is pale yellow.

Distribution.

Reported for the type locality, Rey Island, Pearl Islands, Panamá.

Remarks.

Hickson (1928) described this species with one colony from Panamá. He indicated that the colour of the colony was pale umber brown, darker than the holotype which is pale yellow; we assumed that the colony was decoloured when preserved. The species is different from the others found in the area and we have not collected this species in any of our recent surveys in Panamá. According to Hickson 1928 this species is closely related to Muricea hispida Verrill, 1866 and Muricea horrida Möbius, 1861; however, the characteristic tubular calyces of these species separate Muricea mortensenii , which has shelf-like calyces. The species can be placed in the same group together with Muricea californica and Muricea plantaginea based on the lack of unilateral spinous spindles as structural part of coenenchyme and calyces, the thin branches, and the fan-shaped colony that have one or more planes. The holotype is the only colony presently found of Muricea mortensenii .