Torquatella imperforata, 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 : 509-510

Torquatella imperforata n. sp.

( Figs 29–31)

Etymology. Alluding to the non-foraminate ooecium.

Material examined. Holotype: NIBRIV0000805892, 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, small, 4.7 mm across. Autozooids with irregular indistinct boundaries except at margin, frontal shield porcellanous, surface topography irregular, sparsely porous (fewer than a dozen pores). Orifice a little wider than long, anter proportionately large, delimited from broad shallow poster (sinus) by small triangular condyles in proximolateral corners. Peristome well developed, forming thick crescentic ridge around proximal half of orifice. No oral spines.

Avicularia not in every zooid, adventitious, set singly on one side of inner face of peristome. Rostrum and opesia roundly triangular, edge of latter at midline of peristome; face of avicularium concave, curving obliquely laterally within curvature of peristome, rostral rim slightly projecting, crossbar thin.

Most zooids in colony ovicellate. Ooecium recumbent on distal zooid, subglobular or with slightly flattened apex, opening above zooidal operculum, skeletal surface smooth, non-foraminate, proximal margin becoming elevated and continuous with orificial peristome.

Interzooidal communications via basal pore-chambers, a large distolateral pair and smaller distal pair. Ancestrula not seen.

Measurements. ZL 129–250 (179) µm; ZW 90–159 (124) µm; OrL 32–51 (37) µm; OrW 38–47 (42) µm; AvL 21–28 (25) µm; AvW 11–14 (12) µm; OoL 53–82 (69) µm; OoW 87–112 (98) µm.

Remarks. The present species raises the question of relationship between Torquatella and Predanophora Tilbrook, 2006 . As was pointed out by Tilbrook (2006), the peristomial orifice, which incorporates a more-or-less transversely orientated avicularium on its inner face, is “identical” in the two genera, but he segregated Predanophora on the grounds that the ooecium is bifenestrate, whereas in Torquatella it is unifenestrate. Further, he created a new family, Torquatellidae , monogeneric for Torquatella , on the grounds that its frontal shield is pseudoporous, an alien character in Celleporidae . We would argue that the similarities between Torquatella and Predanophora are greater than the differences. Hence, we unite the two genera and abandon Torquatellidae . Pseudopores are in fact known in Celleporidae , providing the basis for the genus Portalesella Winston, 2005, which, as Berning & Kuklinski (2008) pointed out, is so close to Buffonellaria , with some partially pseudoporous species [including Buffonellaria acutrostris Seo & Gong, 2006 from Jeju Island], that there is little to separate them. In parallel, these authors also noted that pseudopores may be an inadequate basis for separating Predanophora from Torquatella . Gordon (2000) hypothesized that pseudopores are a derived character that originated independently from branching areolar-septular pores in several families.

Torquatella imperforata n. sp. resembles Torquatella duolamellata Scholz, 1991 in having some pseudopores but differs in having a non-fenestrate ooecium. Likewise, T. imperforata differs from Torquatella longiuscula ( Harmer, 1957) n. comb. and Torquatella ensenada ( Tilbrook, 2006) n. comb. in lacking paired lateral windows in the ooecium. Torquatella longiuscula also has a thinner peristome and T. ensenada has a smaller peristomial avicularium and additional, larger frontally adventitious avicularia. An ancestrula was not seen in the holotype colony of T. imperforata but Tilbrook (2006) noted that it was small and tatiform in T. ensenada .

Jeju Island represents the northernmost distribution of this tropical to subtropical genus. Torquatella duolamellata ranges from the Cook Islands and Vanuatu through the Solomon Islands to the central Philippines; T. ensenada is found in the Solomon Islands, and T. longiuscula from the Red Sea and possibly Sri Lanka.

Distribution. Jeju Island, southern Korea, 20 m depth.

Figures

FIGURE 28. Hippaliosina setiformis Tilbrook, 2006, Munseom Island, showing, at centre, a female zooid (♀) with enlarged orifice and ooecium, surrounded by autozooids with two types of avicularia. FIGURES 29–31. Torquatella imperforata n. sp., holotype, Munseom Island. 29, ovicellate and non-ovicellate zooids from colony margin to colony center; 30, autozooid at colony margin and ooecium of proximal zooid; 31, two orifices, each with an intraperistomial avicularium. FIGURE 32. Stephanollona boreopacifica n. sp., holotype, Munseom Island, showing a six-spined autozooidal orifice (right), ovicellate orifices and two types of adventitious avicularia. Scale bars: 28, 500 µm; 29, 400 µm; 30, 31, 100 µm; 32, 300 µm.