Scientific Name and Authority

Watersipora subtorquata complex   (d'Orbigny 1852)


Watersipora subtorquata is an encrusting bryozoan, but colonies can become erect and leaf-like, with extensively overlapping calcareous crusts and curled edges. The crusts are often grayish black or dull-orange, with bright orange (New Zealand) or purplish red (Korea) growing edges. Zooids are roughly elongate-rectangular, 740-1,500 µm X 290-680 µm in size. The frontal shield is perforated by pseudopores. The operculum is strongly pigmented with a dark, broad, biconcave band proximally, gradually spreading around paired clear areas. The polypides have orange lophophores 740 X 850 µm long, and 24 tentacles (Gordon 1989). The orifice is slightly wider than the long, proximal edge, with a V-shaped or rounded sinus and approximately 130 X 260 (mean ~230) µm in size. It occupies less than 10% of the total zooid area with a proximal sinus demarcated by condyles, ~55 × 115 µm (Ryland et al. 2009). There are no oral spines or avicularia, and no ovicells (description from Gordon and Mawatari 1992; Seo 1999; Ryland et al. 2009).

NOTE: A recent revision of the taxonomy of the genus Watersipora presented a drastic change in the nomenclature and worldwide biogeography of the genus. According to Vieira et al. (2015), W. subtorquata is absent from the West Coast of North America. On their map, the 3 species on the West Coast are W. subatra, W. atrofusca, and W. arcuata. Watersipora subatra occurs in the Western Pacific from Japan to New Zealand as well as the West Coast, while W. subatra was identified only from California and Pacific Mexico. Watersipora subtorquata is widely distributed in the tropical subtropical Atlantic and Mediterranean , Red Sea, and Indo-West Pacific. Another previously identified species W. subovoidea has been abolished, and partially synonymized with an earlier name, until recently regarded as obsolete, W. cucullata (Vieira et al. 2015). This worldwide revision of the genus is at odds with current molecular studies (Mackie et al. 2006; Mackie et al. 2012). Vieira et al.'s (2015) map includes only a small number of West Coast samples. A larger regional sample will be required to reconcile morphological and molecular taxonomy of Watersipora on the West Coast of North America. Until this is available, we will use the names W. subtorquata, W. n. sp. In NEMESIS.

Taxonomic Classification:

Kingdom: Animalia
Phylum: Bryozoa
Class: Gymnolaemata
Order: Cheilostomata
Suborder: Ascophora
Family: Watersiporidae
Genus: Watersipora
Species: subtorquata Complex


Escharina torquata (d'Orbigny, 1842)

Lepralia cucullata (Osburn, 1914)

Watersipora cucullata (Marcus, 1937)

Potentially Misidentified Species:

Watersipora arcuata

Banta 1969 Described from San Diego, where it was a recent introduction. Possibly native to tropical-subtropical East Pacific, introduced to Hawaii, Australia, and New Zealand (Banta 1969; Mackie et al. 2006; Mackie et al. 2012).

Watersipora n. sp.

This newly identified, undescribed species is morphologically nearly identical to W. subtorquata but distinct at the molecular level (Mackie 2006; Mackie et al. 2012). So far, it is known only from California and South Korea.

Watersipora subovoidea

(d'Orbigny 1852) Described from the Aegean Sea. Re-described and redefined by Ryland et al. (2009).