Hippopodina adunca Tilbrook 2006
- Dataset
- Taxonomy and diversity of coelobite bryozoans from drift coral cobbles on Co To Island, northern Vietnam
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Bryozoa
- class
- Gymnolaemata
- order
- Cheilostomatida
- family
- Hippopodinidae
- genus
- Hippopodina
- species
- Hippopodina adunca
description
(Fig. 10 A)
description
Measurements. AzL, 0.73 – 1.00 (0.850 ± 0.080); AzW, 0.56 – 0.84 (0.670 ± 0.079); OrL, 0.24 – 0.26 (0.248 ± 0.008); OrW, 0.19 – 0.24 (0.213 ± 0.015) (n = 15, 1). OrL, ooeciate zooid, 0.224; OrW, ooeciate zooid, 0.263 (n = 1). OvL, 0.602; OvW, 0.619 (n = 1). Description. Colony encrusting, sheet-like, unilaminar but occasionally bilaminar due to self-overgrowth. Zooids large, rectangular, delineated by groove. Frontal wall convex, perforated by numerous tiny pseudopores. Orifice hoof-shaped; poster same width as anter or slightly narrower, separated by sharp condyles; proximal margin of orifice straight or markedly concave. Orifices dimorphic, with those of ooecium-bearing zooids wider than those of zooids lacking ooecia. Adventitious avicularia usually paired, sometimes single; each with large chamber lateral to orifice, rostrum long, tapering, directed distomedially and slightly curving around distal end of orifice, crossbar complete. Ooecium prominent, resting on frontal wall of next-distal zooid; circular in outline, perforated over entire surface with tiny pseudopores. Spines lacking.
discussion
Remarks. The large avicularia having setiform mandibles directed distomedially are typical of H. adunca, which, however, also typically has the proximal margin of the orifice straight. While some zooids in the specimens from Co To have the proximal orificial margin nearly straight, most have a concave, distinctly rounded margin. In addition, the only ooeciate zooid observed has a sharp, raised suboral collar. A key character that helps differentiate among Hippopodina species is the ancestrular complex, which forms a triad in in some species (including H. adunca) but a tetrad in others (Tilbrook 1999, 2006). No ancestrular complex was found in the Co To specimens.
distribution
Distribution. Broadly distributed in the Indo-West Pacific, ranging from Mauritius westward to Fiji (Tilbrook 2006) and northward as far as Okinawa, Japan (Dick & Grischenko 2017).
materials_examined
Material examined. VNMN- 0239 (CT- 17), on SEM stub; VNMN- 0240, two colony fragments.
Name
- Homonyms
- Hippopodina adunca Tilbrook 2006