Trimuricea inermis ( Nutting, 1910 )

Samimi-Namin, Kaveh & Van Ofwegen, Leen P., 2016, A revision of Trimuricea Gordon, 1926 (Cnidaria: Octocorallia: Plexauridae) with the description of six new species, Zootaxa 4105 (1), pp. 1-44 : 18-22

Trimuricea inermis ( Nutting, 1910)

( Figs. 13 a–b, 14–15)

Villogorgia inermis Nutting, 1910: 75 , pl. 14 figs. 4–4a, pl. 22 fig. 2; Soest, 1979: 94. Brandella inermis ; Kükenthal, 1924: 216.

Incertae sedis; Stiasny, 1942: 197.

Heterogorgia magna Nutting, 1910: 92 , pl. 16 figs. 1–1a, pl. 22 fig. 15; Kükenthal, 1924: 233; Soest, 197: 89. Echinomuricea magna ; Stiasny, 1942: 197.

Echinogorgia magna ; Breedy & Guzman, 2011: 29.

Material: Holotype of Villogorgia inermis , ZMA COEL. 3635, Siboga station 299, Indonesia, south coast of Rotti island, Cyrus bay, 10° 52.4′ S 123° 1.1′ E, 30 m depth, 27–29 January, 1899. Syntypes of Heterogorgia magna , ZMA COEL 1568 (Pulu Missoa, near Flores, donation de Sisso); ZMA COEL 1569 (Siboga station 299); ZMA COEL 1570, Siboga station 299, Indonesia, south coast of Rotti island, Cyrus bay, 10° 52.4′ S 123° 1.1′ E, 30 m depth, 27–29 January, 1899; ZMA COEL 1571, Siboga station 273, Aru Islands, Pearl Banks, anchorage off Pulu Jedan, 5° 46.7′ S 134° 0.0′ E, 13 m depth, 21–23 December 1899; ZMA COEL 1832 (Boleng Strait, donation de Sisso); ZMA COEL 2665, Siboga station 299, Indonesia, south coast of Rotti island, Cyrus bay, 10° 52.4′ S 123° 1.1′ E, 30 m depth, 27–29 January, 1899; ZMA COEL 2666 (Pulu Missoa, near Flores, donation de Sisso).

Description. The holotype is 7.5 cm high and 4 cm wide, branched in one plane, and without a holdfast or any anastomoses ( Fig. 13 a). The stem is 1 cm long and the stem and branches are 2 mm thick. The calyces are dome shape, closely set together all around the branches, and low; being only a few mm in height and 1 mm in diameter. The points have triradiates ( Fig. 14 a), along with curved, hockeystick or boot-shaped sclerites, or spindles ( Fig. 14 b), 0.10–0.20 mm long. The upper ray of the triradiates and upper part of the spindles is slightly echinulate for up to 0.10 mm. The collaret spindles are up to 0.25 mm long ( Fig. 14 c); the middle part of the convex side is slightly more tuberculate than the concave side and both the ends. Tentacle scales were not observed.

The calyces have thornscales, 0.15–0.30 mm long, with an echinulate thorn up to 0.15 mm long ( Fig. 14 d). The thornscales have simple branched roots with simple tubercles.

The coenenchyme has narrow spindles, 0.10–0.35 mm long, with simple tubercles ( Fig. 14 e). Some of these sclerites have side branches.

Colour. The preserved colony is light brown and all sclerites are colourless. There is no information about the colour of the live colony or the polyps.

Remarks. Apparently the colony has been sampled several times as the original description mentioned it to be 8.9 cm high and 8.3 cm wide ( Nutting, 1910: pl. 14 fig. 4).

The specimens described as Heterogorgia magna , by Nutting (1910) slightly differ from the holotype of T. inermis . They have a darker brown colour and show several anastomoses. As we regard these differences to represent intraspecific variation we synonymize here Heterogorgia magna with Trimuricea inermis . It remains puzzling why Nutting described this species twice, in two different genera. For comparison, colony ZMA COEL 2665 is shown in Fig. 13 b and its sclerites in Fig. 15 . Stiasny (1942) considered Heterogorgia magna as Echinomuricea and Villogorgia inermis as Incertae sedis and also failed to recognize them as one and the same species.

One syntype of Heterogorgia magna , from Siboga station 313 (Lesser Sunda Islands, Sumbawa Island, Saleh Bay, 36 m depth), was donated to Iowa State University (Soest, 1979), and is now deposited in the Smithsonian Museum of Natural History (USNM 43083), but a few fragments remain at the RMNH.

Trimuricea inermis resembles T. bicolor n. sp. The coenenchymal spindles of T. bicolor are longer and narrower and only ornamented with sparsely distributed, simple and notably smaller tubercles. Also, the collaret sclerites are much longer and the thornscales have a far less complex base consisting of long, narrow arms that are unbranched.

Figures

FIGURE 13. Colonies: a, holotype of Villogorgia inermis Nutting, 1910, ZMA COEL. 3635; b, syntype of Heterogorgia magna Nutting, 1910, ZMA COEL. 2665; c, holotype of Trimuricea omanensis, RMNH Coel. 41599.

FIGURE 14. The sclerites of the holotype of Villogorgia inermis Nutting, 1910, ZMA COEL. 3635: a, point triradiates; b, point spindles; c, collaret spindles; d, calicular thorn scales; e, coenenchymal spindles. Scale at ‘ a’, applies to a, b, and c.

FIGURE 15. The sclerites of a syntype of Heterogorgia magna Nutting, 1910, ZMA COEL. 2665: a, point triradiates; b, point spindle; c, collaret spindles; d, calicular thornscales; e, coenchymal spindles.