Amathia acervata Lamouroux, 1824

Seo, Ji-Eun, Chae, Hyun Sook, Winston, Judith E., Zágoršek, Kamil & Gordon, Dennis P., 2018, Korean ctenostome bryozoans-observations on living colonies, new records, five new species, and an updated checklist, Zootaxa 4486 (3), pp. 251-283 : 274-275

Amathia acervata Lamouroux, 1824

( Fig. 16 )

Amathia acervata Lamouroux, 1824: 45 ; Jelly 1889: 10; Hirose et al. 2017.

Serialaria acervata: Blainville 1834: 476 ; Deshayes & Milne Edwards 1836: 170; d’Orbigny 1853: 595.

Non Amathia acervata: d’Hondt 1979: 10 , 16; 1983: 65, fig. 36E; d’Hondt 1991: 163, 165 (part); Gordon et al. 2009: 288. [These all refer to A. bicornis .]

Non Amathia vidovici: d’Hondt 1991: 165 [These refer to A. acervata ].

Material examined. MBRBK1710 , Tongyeong yacht anchorage, South Sea, 34.4934°N, 128.2600°E, 17 August 2015, depth 30 cm.

Description. Colonies forming erect, bushy and branching tufts attached to algae and other substrata ( Fig. 16A–D ). Anticlockwise (usually) spirals of zooid clusters grouped along narrow (about 1.4 mm width) cylindrical stolons. Zooids tilted relative to stolon axis, narrow (about 0.5 mm long, 0.12 mm wide), tubular and connate and more thickly cuticularized at distal ends, a cluster consisting of 12–15 pairs ( Fig. 16A, B ). Clusters spiral about 1.5 turns around stolon (clusters c. 0.6–1.4 mm long). Stolon branching mostly trifurcate. Color of alcohol-preserved specimens whitish tan. Polypides with 8 tentacles.

Remarks. Bushy Amathia species found in Asian waters have usually been attributed to Amathia convoluta (Lamarck, 1816) or Amathia distans Busk, 1886 , species with Atlantic distributions. Hirose et al. (in prep.) have made a morphological and molecular study of three Amathia species in Japan, including the redescription of the holotype of Amathia acervata . This is the first record of the species in Korea. Another Japanese species, presently undescribed (Hirose et al. in prep.) is more robust, with slightly larger stolons and zooids with darker-brown pigmentation and mostly bifurcate branching. It may also be found to occur in Korea. No living specimens were found during our survey, but MBRBK houses jars of preserved material.

Distribution. Korea: Japan Sea (East Sea) coastal localities. Also Pacific coast of Japan.

Figures

FIGURE 16. Amathia acervata Lamouroux, 1824, Tongyeong yacht anchorage, south Sea (MBRBK1710). A. Branch clusters on stolons. B. Closer view of same area. C. Branch bifurcation and part of two zooid clusters. D. Distal part of a single cluster. Scale bars: A, B = 1.2 mm; C, D = 0.47 mm.