Themiste (Lagenopsis) cymodoceae (Edmonds, 1956)

Adrianov, Andrey V. & Maiorova, Anastassya S., 2012, Peanut worms of the phylum Sipuncula from the Nha Trang Bay (South China Sea) with a key to species, Zootaxa 3166, pp. 41-58 : 46

Themiste (Lagenopsis) cymodoceae (Edmonds, 1956)

( Fig. 2 D)

Material. Nha Trang Bay: Diamond Bay, 1–2 m depth, coral rubble, 1 specimen.

Description. Trunk pyriform or flask-shaped, 4 mm long, 2 mm wide in anterior trunk, about 2 mm in width in posterior trunk. Introvert about 2.5– 3 X shorter than trunk length, pale, without pigmented collar; hooks absent. Tentacular apparatus with four short stems; stems are equal in size, with bush-like tentacular branches; tentacles brown proximally, and in living specimens yellow distally.

Discussion. T. cymodoceae , T. lageniformis and T. dehamata are the only three species in the subgenus Themiste (Lagenopsis) that have no introvert hooks. T. lageniformis is well distinguished from T. cymodoceae by having a purple pigmented introvert collar. T. dehamata is characterized by an elongated cylindrical trunk and tentacular stems of unequal length, while T. lageniformis and T. cymodoceae possess a pyriform trunk and tentacle stems of equal length.

In contrast to the smaller bodied T. lageniformis , adult specimens of T. cymodoceae (previously known only from Australia) are much larger (trunk length commonly more than 40 mm). This is the first record of an adult specimen (with mature eggs) with trunk only 5 mm in length. It inhabits intertidal and shallow water areas, seagrass beds, and dead corals.

Figures

FIGURE 2. A – B. Nephasoma pellucidum. A) lateral view, introvert everted; B) hook. C) Thysanocardia catharinae, lateral view, introvert everted. D) Themiste cymodoceae, dorsal view, introvert everted. Scale bars: A, 5 mm; B, 100 µm; C – D, 2.5 mm.