Diplosoma simile (Sluiter, 1909)

Hirose, Euichi & Nozawa, Yoko, 2020, Fig. 6 in Bruggmanniella sanlianensis Lin, Yang & Tokuda, 2020, sp. nov., Zoological Studies 59 (19), pp. 1-11 : 4

Diplosoma simile (Sluiter, 1909)

Specimens: NMNS-8141-004 (Maobitou), -021 (Shimen), -022 (Wushibi).

Colonies were irregularly shaped sheets of 1-2 mm thick and firmly attached to the dead coral branch and coral limestone ( Fig. 2G ). The pattern of stigmata was 6-6-6-5, and the retractor muscle emerged from the bottom of the thorax ( Fig. 2H ).

An outbreak of D. simile colonies has threatened coral reef communities in Fiji and American Sāmoa ( Littler and Littler 1995; Vargas-Ángel et al. 2009). It is possible that a Diplosoma sp. killing Acropora corals on Hainan Is. (South China Sea) may be D. simile ( Li et al. 2016) , although the zooid morphology should be examined to confirm the species identity.

Figures

Fig. 2. Didemnum and Diplosoma species. (A, B), Didemnum molle at Shimen (A, colonies; B, tunic spicules). (C, D), Diplosoma gumavirens at Xiaoyeliu (C, colonies; D, thorax with 5-5-5-4 pattern of stigmata). (E, F), Diplosoma ooru at Gonzibi (E, colonies; D, thorax with 5-6-5-4 pattern of stigmata). (G, H), Diplosoma simile at Maobitou (G, colonies; H, thorax with 6-6-6-5 pattern of stigmata). (I, J), Diplosoma virens at Gonzibi (I, colonies; J, thorax with 6-6-6-5 pattern of stigmata). (K, L), Diplosoma watanabei at He-mei (K, colonies; L, thorax with 6-7-6-5 pattern of stigmata). White arrows in A indicate some cloacal aperture. an, anus; es, esophagus; rm, retractor muscle. Scale bars: B = 20 µm; D, F, H, J, L = 0.1 mm.