Thouarella andeep Zapata-Guardiola and López-González, 2010b

TAYLOR, M. L., CAIRNS, S. D., AGNEW, D. J. & ROGERS, A. D., 2013, <strong> A revision of the genus <em> Thouarella </ em> Gray, 1870 (Octocorallia: Primnoidae), including an illustrated dichotomous key, a new species description, and comments on <em> Plumarella </ em> Gray, 1870 and <em> Dasystenella </ em>, Versluys, 1906 </ strong>, Zootaxa 3602 (1), pp. 1-105 : 71-72

16. Thouarella andeep Zapata-Guardiola and López-González, 2010b

Fig. 40c,d

Thouarella andeep Zapata-Guardiola & López-González, 2010b: 142–145 , fig. 8c,d, 11–13

Material unavailable: Holotype, ZMH C11744, R/ V Polarstern, Antarktis XXIV/2, sample no. PS7/048–01, off Atka Bay , Antarctica, 70˚24’S, 8˚19’43”W, 601.8 m, 17 Jan 2008, 2 fragments.

Material examined: Paratype, USNM 1123418, details same as holotype.

Other material: USNM 98298, R/ V Eltanin, sta. 1089, Clarence Island, NE of South Shetland Islands, sub- Antarctic , 60˚47’S, 53˚30’W, 641 m, 17 Apr 1964 ; USNM 1130294, R/V Hero , cruise 721, sta. 1144, Bismarck Strait, Anvers Island , Palmer Archipelago, Antarctic Peninsula, 64˚52’09”S, 63˚50’09”W, 440–480 m, 14 Mar 1972; USNM 1130291, R/V Hero , cruise 824, sta. 35–B, 64˚50’33”S, 63˚51’00”W, 312–330 m, 26 Mar 1982 , 1 fragment; USNM 1130289, R/ V Eltanin, cruise 12, sta. 1081, east of South Orkney Islands, Scotia Ridge , Antarctica, 60˚34’S, 40˚44’W, 345–350 m, 13 Apr 1964 ; USNM 98276, R/ V Eltanin, cruise 27, sta. 1870, Cape Adare, Victoria Land, Ross Sea , Antarctica, 71˚16’S, 171˚31’E, 659–714 m, 14 Jan 1967 ; USNM 85296, R/ V Eltanin, cruise 11, sta. 970, SW coast of Staten Island , Tierra del Fuego, Argentina, 54˚59’S, 64˚53’W, 586–641 m, 11 Feb 1964 , 1 fragment; USNM 1130287, R/ V Eltanin, cruise 12, sta. 1089, NE of Clarence Island, South Shetland Islands, Antarctic Ocean , 60˚47’S, 53˚30’W, 641 m, 14 Apr 1964; SMF, EPOS 3 , sta. 293, GSN 15, 20 Feb 1989, 1 colony, no location information.

Description

Description modified from Zapata-Guardiola and López-González (2010b):

The colonies appear alternately pinnate although branching is in 3 directions with 2 pinnate rows creating a plane and one row of branching between these 2 rows. The colonies are light pink or white with a bronze axis. The largest colony is 8 cm long ( USNM 98276) with a very rigid stem and branchlets, the latter being 21–22 mm long.

The polyps of the paratype are isolated, with a density of 10–11 per cm (more clustered at branchlet tip) and upwardly inclined 80–90° from branchlets and main stem. They are 1.9–3.4 mm high, very wide at 0.7–0.95 mm and distally flared in shape, with a tall conical operculum. The polyps have 7 longitudinal rows of body-wall scales, quickly reducing to 4 at the base with 4–5 scales in each abaxial row.

There are 5 to 6 tongue-shaped accessory operculars, 240–420 µm high, 70–300 µm wide, which lie underneath the operculars. The inner surface is tuberculate across the proximal half, smooth distally, and has no keel whilst the outer surface is smooth sometimes with low striations proximally.

The operculars are arranged in 2 alternate circles of 4, they are tongue-shaped, sometimes constricted distally, 510–1100 µm high, 340–520 µm wide. The outer circle of operculars is larger than the inner circle. The inner surface of the larger scales have striations perpendicular to the distal edge, no distinct keel, and densely arranged tubercles proximally. Smaller operculars have a smooth inner surface and no striations. The outer surface has striations radiating from a central proximal area.

The marginals have a wide triangle-shape with a pointed distal edge, which can be acutely elongated. The scales are 950–1320 µm high and 740–990 µm wide. The inner surface can have a complex multi-keel ( Fig. 40c,d ) or an area of striations. The area adjacent to the keel is smooth, and there are tubercules densely arranged below this. The outer surface is densely covered in granules.

The submarginals are not differentiated from body-wall scales and both are irregularly fan-shaped, elliptical, and oval, with a maximum height of 540–840 µm. The inner surface has a dense covering of tubercules, sometimes with a very narrow smooth band along the distal edge whilst the outer surface has densely arranged granules. As with all body-wall sclerites, the distal edge is finely serrate and the proximal edge coarsely lobate.

The coenenchymal scales have a diverse range of shapes from circular to oval to lobate. These scales have a densely tuberculate inner surface and an outer surface with densely arranged granules, that is also often heavily striated. The scale has a maximum length of 60–93 µm.

The images of this species are found in the original description by Zapata-Guardiola and López-González (2010b).

Distribution

The specimens described here extend the range of T. andeep to include the southwest Atlantic Ocean, off the tip of South America, and circum-Antarctic areas, at depths from 312– 714 m.

Remarks

Thouarella andeep was originally described as having a bottlebrush colony. This is true in the strictest sense of the word, however, as in many Thouarella species , branching is not in all directions (usually just in 3), the overall appearance of which can look alternately pinnate. We also add that the marginals do have a keel (see Fig. 40c,d , from paratype).

Comparisons

With four to five scales in each longitudinal abaxial row, a bottlebrush branching arrangement, and distally flared polyps, Thouarella andeep is comparable to: T. minuta , T. pendulina , T. hicksoni , T. variabilis , T. striata , and T. brucei ( Table 3). Thouarella minuta , T. pendulina , T. hicksoni , and T. variabilis all have polyps smaller than those of T. andeep . Of the remainder, T. striata often has distinct striations on the outer surface of the body-wall sclerites, whereas T. andeep has fine granules, and the latter also lacks the striations common on the inner surface of T. striata sclerites. Furthermore, T. brucei has a keel on the operculars that is lacking in T. andeep . Thouarella brucei also usually has smaller polyps than T. andeep .

Figures

FIGURE 40. Thouarella parva, holotype: a) lateral polyp view, modified from Fig. 1 Kinoshita, 1908d; b) sclerites from Kinoshita, 1908d—I. accessory operculars, II. operculars, III. marginals, IV. submarginals, V,VI. body-wall scales. Thouarella andeep, USNM 1123418: c,d) inner surface of marginal scales.