Trichogorgia utinomii, Cordeiro, 2019

Cordeiro, Ralf T. S., 2019, A review of the genus Trichogorgia (Cnidaria, Octocorallia), including descriptions of new species, Zootaxa 4706 (4), pp. 517-530 : 520-522

publication ID

https://doi.org/ 10.11646/zootaxa.4706.4.2

publication LSID

lsid:zoobank.org:pub:728CBA79-31A4-45F9-94B8-13AF43B5CCAA

persistent identifier

https://treatment.plazi.org/id/2614B657-5B28-FFE2-82E0-FF53FB938540

treatment provided by

Plazi

scientific name

Trichogorgia utinomii
status

sp. nov.

Trichogorgia utinomii sp. nov.

Figs. 1–2 View FIGURE 1 View FIGURE 2

Not Malacogorgia capensis Hickson 1904: 226–227 , pl. VII, fig. 5, pl. VIII, figs. 10–11.

Malacogorgia capensis . Utinomi 1964: p. 9, fig. 5, pl. II, figs. 4–5.

Holotype: Eltanin R /V, USAP expedition, st. 1521, 54°07’59”S, 52°12’29”W (Scotia Sea), 419–483 m, 30 Jan 1966 ( USNM 77385 About USNM , one colony and three fragments). GoogleMaps

Paratypes: Eltanin R /V, USAP Expedition, st. 428, 57°48’29”S, 62°40’01”W, 662–1120 m, 5 Jan 1963 ( USNM 77374 About USNM , one colony and one fragment) GoogleMaps ; Eltanin R /V, USAP Expedition, st. 1520, 54°08’31”S, 52°04’01”W, 1244– 1771 m, 30 Jan 1966 ( USNM 77384 About USNM , two small colonies) GoogleMaps

.

Description: Uniplanar flabellate and dichotomously branched colonies, up to 17 cm tall and 13 cm wide, all lacking holdfasts, which probably were attached to solid substrata ( Fig. 2 View FIGURE 2 A–C). Colonies quasi-bilaterally symmetrical and slightly concave. Main stem 3.7–12.7 mm long and 0.7–2.6 mm in diameter. Axis calcified, circular in cross-section ( Fig. 3B,E View FIGURE 3 ), not undulated, with concentric layers ( Fig. 3B,D,E,F View FIGURE 3 ) and inconspicuous longitudinal canals perforating its medular region ( Fig. 3A,C View FIGURE 3 ). Axis golden in basal parts, becoming pale iridescent to translucent towards branchlets. Branchlets arising up to the 5 th order ( Fig. 2A,B View FIGURE 2 ). Primary branchlets 5.5–13 mm long and new branchlets distant 11.2–22 mm from each other. Main stem and proximal branchlets usually shorter, stiff and oriented upwards, whereas distal branchlets are long and flexible. Terminal branches up to 14 cm long. Polyps well separated, 0.78± 0.55 mm from each other (n = 30), occurring on the entire coral, except on the main stem ( Fig. 2B,C View FIGURE 2 ), longitudinally arranged in two alternate rows on the branchlets ( Fig. 2D View FIGURE 2 ), slightly facing the concave face of the colony. Distally, polyps arranged in a single line. Each of the eight tentacles of polyps bears 8–15 pairs of pinnules (~ 0.15 mm long) on both sides ( Fig. 2E View FIGURE 2 ). Based on measurements of 30 zooids randomly chosen among the specimens, mean polyp length when fully expanded is 2.06± 0.48 mm, and polyp width 0.89± 0.2 mm. When completely contracted, polyps are 0.58± 0.1 mm long and 1.15± 0.29 mm wide. Coenenchyme transparent throughout colonies. Pharynx slightly darker than rest of soft tissues, visible through the polyp body wall. Polyps and coenenchyme completely devoid of sclerites.

Comparisons: The new species differs from its congeners in having no sclerites at all, which would group it with Trichogorgia lyra Bayer & Muzik, 1976 and T. capensis ( Hickson, 1904) . I examined specimens of T. lyra (including types) and, contrary to expectations, most showed very rare translucent and fragile scales in the main stem coenenchyme ( Fig. 6B View FIGURE 6 ). According to Hickson’s description, fully expanded polyps in T. capensis are less than 1 mm tall (up to 0.65 mm), whereas in T. utinomii they often exceed 2 mm in similar colony sizes ( Table 1 View TABLE 1 ), being opposite and alternately disposed, respectively (see Hickson, 1904, pl. VII fig. 5 and pl. VIII figs. 10–11). Moreover, T. capensis is known from depths <100 m, in contrast with a much deeper range for the new species (see Distribution).

Remarks: This species was first recorded by Utinomi (1964) as Malacogorgia capensis Hickson, 1904 in the Southern Ocean (500–590 m). Our specimens were collected almost contemporarily with Utinomi’s, and there are no reports of new collections since then. Regarding ecological associations, several amphipods were found on branches of the holotype. Besides that, some polyps are oddly swollen in their proximal portion, indicating sexual maturation ( Fig. 2F View FIGURE 2 )

Etymology: Named in honor to Dr. Huzio Utinomi, a prominent octocoral taxonomist, who first record this species in the Southern Ocean.

Distribution: Known only from the type locality, the Scotia Sea, 419–1244 m.

Kingdom

Animalia

Phylum

Cnidaria

Class

Anthozoa

Order

Alcyonacea

Family

Chrysogorgiidae

Genus

Trichogorgia

Loc

Trichogorgia utinomii

Cordeiro, Ralf T. S. 2019
2019
Loc

Malacogorgia capensis

Hickson 1904: 226
1904
Loc

Malacogorgia capensis

Hickson 1904
1904
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