Adeonellopsis periculosa Liow & Gordon 2020, n. sp.
Creators: name: Liow, Lee Hsiang
name: Gordon, Dennis P.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Bryozoa
Gymnolaemata
Cheilostomatida
Adeonidae
Adeonellopsis
Adeonellopsis periculosa

description: Adeonellopsis periculosa n. sp.
(Figs 3D, 11, 12; Tables 1, 2)
Etymology. Latin periculosus, dangerous, alluding to the large, presumably defensive, vicarious avicularia.
Material examined. Holotype: Australian Museum U. 5796, Stn I89, 29.4217° S, 168.0033° E, Norfolk Ridge, 65 m. Paratypes: Australian Museum U. 5797, same data as holotype. NIWA 144897, 146072, same data as holotype.
Diagnosis. Branches flattened or, more generally, slightly curled, 2.5–4.5 mm wide. Autozooids averaging 454 μm long, 241 μm wide. Autozooidal spiramen mostly with 3 pores. Large suboral adventitious avicularium on every zooid, including gonozooids, its elevated distal tip often projecting above proximal orificial rim. One or two additional smaller such avicularia may occur at proximal end of zooid. Vicarious avicularia at intervals on or adjacent to colony margins and proximal to branch bifurcations. All avicularia with open-channelled acute rostral tip. Gonozooids large, with dimorphic orifices and vestigial ooecia (visible during gonozooidal ontogeny); spiramen like that of autozooids but larger, with 4–6 pores.
Description. Mature intact colony not seen; largest fragment (holotype) 20 mm high, 21 mm broad, repeatedly bifurcating every 4–4.8 mm, even trifurcating, turned back on itself, with curled branches and branch fusions. Dried colour pale grey; residual patches of pigment on some zooids indicate purplish coloration in life. Branch diameters varying with age of colony from 2.2 to 4.5 mm. Autozooids arranged in quincunx; 8–10 longitudinal series across width of branch (Fig. 11A).
Neanic autozooids (Fig. 11B) more or less subhexagonal, becoming more elongate-rectangular with ageing and secondary calcification. Interzooidal boundaries indicated by thin lines of calcification in interzooidal furrows, which are bordered by 17–21 areolar pores in a series around the entire zooidal margin; a few additional areolar pores closer to orifice and suboral avicularium; marginal areolae sometimes merging as zooids acquire additional calcification. Average zooid length and width 454 μm and 241 μm, respectively.
Autozooidal peristomial orifice transversely D-shaped to subrounded, becoming sunken within distally cowled deepening peristome as zooids age. Interior view of orifice shows a pair of blunt condyles, one in each proximolateral corner. Multiporous spiramen (Fig. 12A) in frontal depression, central in zooid or in proximal half but position can vary; mean length 63 μm, mean width 50 μm; spiraminal pores 2–5, mostly 3, varying a little in size and shape, each with 6–8 spokes, only some of which may touch. Spiramen becoming deeply sunken and somewhat concealed as frontal shield thickens and the frontal opening reduces in diameter.
Adventitious avicularia (Fig. 11B, D) varying in size, position and orientation but all having same form, i.e. elongate-triangular rostrum with open-channelled acute tip and smooth raised (gymnocystal) margins, common rostral-opesial foramen, semicircular opesial margin, granular crescentic cryptocyst; no pivot bar but short curved pivot ridges at rostral-opesial transition; cryptocyst smooth. Suboral avicularium moderately large, the rostrum elevated obliquely frontalwards, directed mid-distally, its tip often projecting above the orifice margin. One or two additional similar avicularia laterally or midproximally in many ephebic zooids, pointing in any direction.
Vicarious avicularia (Figs 11A; 12 B–D) at intervals on or adjacent to colony margins and proximal to branch bifurcations.All avicularia with open-channelled acute rostral tip and groove (Fig. 11D, E), the rostral rims frontally arcuate in profile.
Gonozooids (Figs 11 A–C; 12B) large, showing vestigial ooecia during gonozooidal ontogeny; orifice averaging 405 μm wide. Spiramen (Fig. 11C) like that of autozooids but larger, with 4–6 pores having spokes that may or may not touch.
Ancestrula and early astogeny not seen.
Remarks. Adeonellopsis periculosa n. sp. has a very similar colony form to that illustrated for the shallow coastal Victorian species Adeonellopsis parvipunctata MacGillivray, 1886, which apparently has, however, only a single, spoked spiraminal pore in autozooids and small latero-oral avicularia. Adeonellopsis sparassis (Ortmann, 1890), apparently endemic to Japan, is also very similar, but differs in having larger mean autozooid size, vicarious avicularia confined to branch margins and gonozooids with 8–10 spiraminal pores (Hirose 2016). The number of spiraminal pores in the gonozooid of A. periculosa n. sp. is the fewest (4–6) of any of the new species described herein (Table 2).
Distribution. Norfolk Ridge south of Norfolk Island (Australian Exclusive Economic Zone), 65 m.
description: Published as part of Liow, Lee Hsiang & Gordon, Dennis P., 2020, New species of Adeonellopsis (Bryozoa: Adeonidae) from southern Zealandia and the western Tasman Sea, pp. 301-331 in Zootaxa 4895 (3) on pages 316-319, DOI: 10.11646/zootaxa.4895.3.1, http://zenodo.org/record/4326650