Adelogorgia phyllosclera Bayer, 1958

Breedy, Odalisca, 2018, Revision of the genus Adelogorgia Bayer, 1958 (Cnidaria: Anthozoa: Octocorallia) with the description of three new species, Zootaxa 4369 (3), pp. 327-348 : 330-333

Adelogorgia phyllosclera Bayer, 1958

Figs. 1–2 , 3 A-B

Adelogorgia phyllosclera Bayer, 1958: 46 –48; Harden 1979: 137 –138.

Material examined.

Holotype: USNM 50186 , dry preserved, La Jolla Canyon , California, 30–33m, L. Limbaugh, 19 March 1954.

Paratypes: USNM 50187, 2 specimens, dry preserved, La Jolla Canyon, 20–23m, L. Limbaugh, 8 October 1955. USNM 50188, 6 specimens, dry preserved, La Jolla Canyon, 50–57m, L. Limbaugh, 8 October 1955.

Diagnosis. Colony flabelliform, branching lateral, dichotomous and irregular, mostly in one plane, without anastomoses. Branches 2–4.5 mm in diameter, sinuous, with clavate tips; terminal branches 3-4 cm long; main stem up to 6 mm diameter ( Figs. 1 A-B). Axes of gorgonin layers, loculi between lamellae and central core with complex meshes of not mineralised filaments ( Fig. 3A ). Axes dark brown, lighter at branchlets. Polyps distributed all around branches, 2-2.5 mm apart. Anthocodia with 2–4 slightly curved spinous rods 0.1–0.17 mm long and 0.02–0.045 mm wide, at each side of points ( Fig. 2A ), without collaret. Polyp mounds almost flat, blending with adjacent coenenchyme or forming low rims around polyps, without a special type of sclerites but mostly containing leaf clubs and spindles. Coenenchyme contain double discs with serrate edges or foliate crests, 0.089–0.12 mm long and 0.075–0.09 mm wide ( Fig. 2E ), tuberculate spindles, 0.13–0.2 mm long and 0.05–0.095 mm wide ( Fig. 2C ), and leaf clubs 0.1–0.19 mm long and 0.06–0.085 mm wide ( Fig. 2B ). Axial sheath containing less developed spindles, radiates and capstans 0.08–0.1 mm long and 0.05–0.07 mm wide ( Fig. 2D ).

Colony colour red ( Figs. 2 A-B) and sclerites red and colourless ( Fig. 2C ).

Distribution. La Jolla, California (type locality), 20- 57 m. Harden (1979) reports samples for outer coast of Baja California, Mexico from 91.4 m.

Variability. The species has some variation in branch diameter; some paratypes have branches a few millimeters thinner, 2–3.5 mm in diameter. The red colour of the colonies varies from darker to lighter hues.

Remarks. Bayer (1958) pointed out the similarity in external appearance of this species and Psammogorgia arbuscula Verrill, 1868 , but the different sclerite composition and types justified the new taxon. Colonies of Adelogorgia are similar those of Psammogorgia , not only in external morphology but also in habitat preference. Both genera occur in shallow waters, and are also found in mesophotic and deep habitats on similar substrates (pers. obs.). In any case, as in many other gorgonians, the sclerites are the key elements to separate genera. The species of Adelogorgia share the presence of double-disc sclerites conforming to the outer coenenchyme, in contrast to Psammogorgia , which lacks double-discs. The composition of outer coenenchyme sclerites varies in Adelogorgia species. In this sense, A. phyllosclera and the new species A. osculabunda (see description below), contain a similar amount of wide warty spindles and double-discs. For this reason, in unsorted samples of sclerites of these species, the occurrence of double-discs is not as abundant as in the other three species ( A. telones , A. hannibalis sp. nov. and A. adusta sp. nov.). In A. osculabunda the double-discs are less ornamented than in A. phyllosclera . The differences between this species and the others are shown in Tables 1 and 2.

Colony shape: bu, bushy; fla, flabellate, fan shape; spa, sparse, flexible, with few branches

Branching type: dic, dichotomous-like; irr, irregular, not a specific type of branching; lat, lateral

Figures

FIGURE 1. Adelogorgia phyllosclera, USNM 50188 (paratype) (A) colony; (B) detail of the branches; (C) sclerites. A and B photographs by Robert Ford.

FIGURE 2. Adelogorgia phyllosclera, USNM 50188 (paratype) SEM micrographs. (A) anthocodial rods; (B) leaf clubs; (C) spindles; (D) radiates from inner coenenchyme; (E) double-discs.

FIGURE3. Structure of non-mineralised axes:Longitudinal sectionof axial core showing chamberswith fibres (left); detail of fibres (right).(A) Adelogorgia phyllosclera; (B) Adelogorgia telones.