Schizosmittina mabik, Yang & Seo & Gordon, 2018

Yang, Ho Jin, Seo, Ji Eun & Gordon, Dennis P., 2018, Sixteen new generic records of Korean Bryozoa from southern coastal waters and Jeju Island, East China Sea: evidence of tropical affinities, Zootaxa 4422 (4), pp. 493-518 : 501

Schizosmittina mabik n. sp.

( Figs 14, 15 )

Etymology. In acknowledgement of the Marine Biodiversity Institute of Korea (MABIK), which partially supported the present study; used as a noun in apposition.

Material examined. Holotype: NIBRIV0000805885, unique colony found at Munseom Island, Seogwipo , Jeju Island, 24 December 2016, 20 m, on oyster shell, collected by Ho Jin Yang.

Description. Colony encrusting, multiserial, unilaminar, with limited frontal budding and irregular disposition of zooids towards colony center, small, attaining 5 mm in diameter. Frontal shield evenly porous, with 31–49 pseudopores and areolar-septular pores. Orifice with relatively large rounded anter and moderately broad sinus flanked by ledge-like condyles. No oral spines; a pair of tiny ephemeral spine bases seen in a few marginal zooids. No avicularia.

Ooecium recumbent, with smooth ectooecium perforated by c. 20–45 pseudopores, porous area surrounded by thin layer of secondary calcification from adjacent zooids. Lateral margins of peristome in ovicellate zooids tending to be thick, raised, forming a pseudosinus.

No basal pore-chambers; mural septular pores present. Ancestrula not seen.

Measurements. ZL 322–402 (362) µm; ZW 188–361 (257) µm; OrL 60–101 (78) µm; OrW 79–94 (86) µm; OoL 151–160 (156) µm; OoW 173–217 (195) µm.

Remarks. Schizosmittina is primarily an Australasian genus at the present day, although the type species is from the French Miocene ( Vigneaux 1949; Di Martino & Taylor 2017) and the earliest occurrence is the Late Eocene of Hungary ( Zágoršek 2001). Schizosmittina mabik n. sp. is the only known species from the Pacific north of the Equator, inasmuch as Californian Schizosmittina pedicellata Soule, Soule & Chaney, 1995 is actually a species of Schizomavella . We here designate it as Schizomavella pedicellata n. comb.; its suboral avicularium is acute and strictly median, which is not the case in Schizosmittina species, in which it is either absent or, when present, is to one side of the sinus and/or oblique with a rounded rostrum.

Four of the six Recent Southern Hemisphere species have avicularia. Of the two that do not, Schizosmittina melanobater Gordon, 1989 from New Zealand has stouter orificial condyles and many more frontal-shield and ooecial pseudopores than S. mabik n. sp.; Schizosmittina lizzyae Florence, Hayward & Gibbons, 2007 may not even belong to Schizosmittina —it differs in having a single large ooecial foramen.

Figures

FIGURES 14, 15. Schizosmittina mabik n. sp., holotype, Munseom Island. 14, autozooids at colony margin; 15, ovicellate zooids. FIGURES 16, 17. Stephanotheca fenestricella Dick & Grischenko, 2017, Munseom Island. 16, ooecium, ovicellate and autozooidal orifices, and suboral avicularia; 17, autozooidal orifice, condyle and suboral avicularium. Scale bars: 14, 15, 300 µm; 16, 100 µm; 17, 50 µm.