Adeonellopsis wassi, Liow & Gordon, 2020

Liow, Lee Hsiang & Gordon, Dennis P., 2020, New species of Adeonellopsis (Bryozoa: Adeonidae) from southern Zealandia and the western Tasman Sea, Zootaxa 4895 (3), pp. 301-331 : 315-316

Adeonellopsis wassi n. sp.

( Figs 3E , 9 C–D, 10; Tables 1, 2)

Etymology. Honorific for retired bryozoologist Dr Robin E. Wass to acknowledge his contributions to knowledge of Australian Paleozoic and Recent bryozoans.

Material examined. Holotype: Australian Museum U. 5794, from NIWA Stn U 207, 34.1850° S, 151.4333° E, 198 m, New South Wales shelf, Tasman Sea . Paratypes: Australian Museum U. 5795, same data as holotype ; NIWA 144898 , same data as holotype .

Diagnosis. Branches flattened, mostly 3 mm wide. Autozooids averaging 931 μm long, 423 μm wide. Auto-zooidal spiramen mostly with 6–7 pores. Suboral avicularia 1–3, moderate-sized; no additional such avicularia in ephebic zooids. Large vicarious avicularia absent; rather, cystids of marginal avicularia subvicarious with functional rostral-opesial component same size as autozooidal suboral avicularia. Putative gonozooid slightly larger than autozooids with larger spiramen of 14 pores. Adventitious avicularia as for autozooids.

Description. Colony erect, rigid, maximum size not known; longest available branch fragment 4.2 cm, lateral branching sparse, with distance between bifurcations variable, sometimes quite long; branching in same plane. Colour in life unknown; dried fragments pale creamy-brown. Branch widths varying with age of colony, 2.0– 3.8 mm, mostly 3 mm between bifurcations, wider just proximal to bifurcations. Autozooids arranged in quincunx; 6–10 longitudinal series according to branch width ( Fig. 9C ).

Neanic autozooids ( Fig. 9D ) more or less rounded-subhexagonal, becoming more elongate-rectangular with ageing and secondary calcification. Interzooidal boundaries indicated by thin lines of calcification in interzooidal furrows, bordered by 16–26 areolar pores in single series around entire zooidal margin. Zooids relatively large, mean zooid length and width 931 μm and 423 μm, respectively.

Autozooidal peristomial orifice suborbicular to a transversely rounded D-shape. Denticulation ( Fig. 10B ) of inner peristomial margin well developed, sparse or absent. Multiporous spiramen in frontal depression ( Fig. 10A, E ) circular–oval, more or less central; averaging 122 μm long, 96 μm wide; spiraminal pores 5–10, mostly 6–7, each with 4–7 short spokes that do not touch.

Adventitious avicularia ( Figs 9D ; 10A, C ) suboral only, typically 1–2 but increasing to 3 in ephebic zooids; one is placed medially, pointing mostly distally, with a second to one side of it pointing transversely or obliquely toward it; an areolar pore on the opposite side of the median one can later develop into a third such avicularium, converging towards its partners so that the tips of all three somewhat converge. All have the typical form, with a narrow openchannelled rostral tip, smooth raised (gymnocystal) margins, common rostral-opesial foramen with slight denticulation and mostly smooth cryptocyst; no pivot bar but short curved pivot ridges at rostral-opesial transition.

Large vicarious avicularia absent; instead, subvicarious avicularian cystids occur on branch margins ( Fig. 10D ). The functional rostral-opesial (gymnocystal) part of the avicularium has the same size and form as the suboral avicularia of autozooids, the rostral tips frontally elevated.

Only one putative gonozooid seen ( Fig. 10A ), 1104 μm long, 511 μm wide, occurring four zooid lengths be-low a bifurcation. Gonozooid peristomial orifice 147 μm wide, the spiramen larger than autozooids, with 14 pores, each with 4–7 short spokes that do not touch unless pore laterally constricted. Two suboral avicularia like those in autozooids.

Ancestrula and early astogeny not seen.

Remarks. Compared to the two new species described above, Adeonellopsis wassi n. sp. has relatively smaller suboral avicularia, reminiscent of those in Adeonellopsis gemina n. sp. and Adeonellopsis minor n. sp.. Colony form in these latter two species differs markedly, however, being smaller with thinner branches. Overall, A. wassi has the largest zooids of any of the new species described herein. It also has only subvicarious avicularia on its branch margins.

Distribution. Australia: New South Wales shelf, 198 m.

Figures

FIGURE 3. A, B. Adeonellopsis macewindui n. sp.: A. Holotype, NIWA 146070; B. NIWA 146098. C. Adeonellopsis tasmanensis n. sp., composite of three fragments, all NIWA 144892. D. Adeonellopsis periculosa n. sp., holotype, NIWA 146071. E. Adeonellopsis wassi n. sp., composite of three fragments, all NIWA 144898. F, G. Adeonellopsis gemina n. sp.: F. holotype, NIWA 146095; G. Two specimens, NIWA 146073. H. Adeonellopsis minor n. sp., composite of four fragments, NIWA 146152. I. Adeonellopsis gracilis n. sp., composite of two fragments, holotype (larger specimen), NIWA 92745; smaller specimen (separated by thin gap), NIWA 146099. Specimens A–I at same scale; scalebar 5 cm.

FIGURE 9. Adeonellopsis tasmanensis n. sp. (NIWA 144892): A, B. Two gonozooids with varied numbers and orientations of adventitious avicularia. Adeonellopsis wassi n. sp. (NIWA 144899): C. Part of stem near axial bifurcation; the black arrow indicates a zooid (gonozooid?) with an unusually large spiramen. D.Autozooids with paired and single suboral avicularia having varied orientations. Scalebars: A, B, 300 μm; C, 2 mm; D, 500 μm.

FIGURE 10. Adeonellopsis wassi n. sp. (NIWA 144898):A. Autozooids and a possible gonozooid. B. Autozooidal peristomial orifice showing denticulation of inner proximal rim. C. Close-up of suboral autozooidal avicularia; note the pore on the right that may later produce a third avicularium. D. Marginal subvicarious avicularian cystids with small rostral-opesial area. E. Autozooidal spiramen. Scalebars: A, 500 μm; B, C, E, 100 μm; D, 300 μm.