Adeonellopsis gemina, 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 : 319-322

publication ID

https://doi.org/ 10.11646/zootaxa.4895.3.1

publication LSID

lsid:zoobank.org:pub:C6F85190-D79E-429E-9B5B-FD0E54AE96BC

DOI

https://doi.org/10.5281/zenodo.4383116

persistent identifier

https://treatment.plazi.org/id/9DD4BEBF-A3B1-4343-9B4A-25DB67F895A8

taxon LSID

lsid:zoobank.org:act:9DD4BEBF-A3B1-4343-9B4A-25DB67F895A8

treatment provided by

Plazi

scientific name

Adeonellopsis gemina
status

sp. nov.

Adeonellopsis gemina n. sp.

( Figs 3 View FIGURE 3 F–G, 13, 14, 17A; Tables 1, 2)

Adeonellopsis coscinophora var. mucronata: Livingstone 1929: p. 91 . Non Eschara mucronata MacGillivray, 1889.? Adeonellopsis yarraensis: Powell 1967: p. 337 , text-fig. 88. Non Microporella yarraensis Waters, 1881 .

Adeonellopsis yarraensis: Gordon 1984: p. 73 , pl. 24G;

Adeonellopsis pentapora: Gordon et al. 2009: p. 290 View in CoL . Non Adeonellopsis pentapora Canu & Bassler, 1929 View in CoL .

Etymology. Latin gemina , noun, female twin, alluding to the mostly paired suboral avicularia.

Material examined. Holotype: NIWA 146095 View Materials , NIWA Stn D 114, 44.2000° S, 173.3000° E, SE of Banks Peninsula , South Island, 84 m. GoogleMaps Paratype: NIWA 146073 View Materials , same data as for holotype. Other GoogleMaps : NIWA 31485 View Materials , Stn KAH0705/47 ; NIWA 74840 View Materials , Stn TAN1108/122 ; NIWA 146074 View Materials , Stn B175 ; NIWA 146075 View Materials , Stn B488 ; NIWA 146076 View Materials , Stn B567 ; NIWA 146077 View Materials , Stn C706 ; NIWA 146078 View Materials , Stn D131 ; NIWA 146079 View Materials , Stn D132 ; NIWA 146080 View Materials , Stn D133 ; NIWA 146081 View Materials , Stn D144 ; NIWA 146082 View Materials , Stn D173 ; NIWA 146083 View Materials , Stn D200 ; NIWA 146084 View Materials , Stn E817 ; NIWA 146085 View Materials , Stn F94 ; NIWA 146086 View Materials , Stn I85 ; NIWA 146088 View Materials , Stn O840 ; NIWA 146089 View Materials , Stn W74 ; NIWA 146090 View Materials , Stn TAN1108/5 ; NIWA 146091 View Materials , Stn TQI1201/25 ; NIWA 146096 View Materials , Stn KAH1206/4. Also NIWA 146150 View Materials , Pleistocene , Tainui Shellbed , Castlecliff, Whanganui, New Zealand .

Diagnosis. Branches flattened, in several planes, mostly 2 mm wide. Autozooids averaging 443 μm long, 241 μm wide. Autozooidal spiramen mostly with 4 pores. Suboral avicularia frequently paired, small, directed distad or obliquely so; 1–2 additional such avicularia elsewhere on zooid when ephebic. Marginal avicularia vicarious, sub-vicarious and interzooidal. All avicularia with closed (non-channelled) rostral tip. Putative gonozooids with broader orifices and 7–8 spiraminal pores.

Description. Colony erect, bifurcating, intricate, attaining 6–7 cm height and breadth; branches bilamellar, flattened, more or less in same plane or at different angles. Branch widths varying with age of colony from 1.5 to 2.6 mm, mostly 2 mm. Autozooids arranged in quincunx; 8–10 longitudinal series across width of branch ( Fig. 13A View FIGURE 13 ).

Neanic autozooids variably subhexagonal or diamond-shaped (rhombic), or even almost elongate-rectangular, their boundaries becoming irregular and crinkly in older (ephebic) parts of colony. Interzooidal boundaries indicated by thin lines of calcification in interzooidal furrows, which are bordered by 14–19 areolar pores (mostly 15–16) in a series around the entire zooidal margin; no additional areolar pores closer to orifice but one may substitute for an avicularium. Average zooid length and width 443 μm and 241 μm, respectively.

Autozooidal peristomial orifice transversely D-shaped, becoming sunken and transversely oval as zooids age, the distal peristomial rim sometimes slightly elevated and cowled. Denticulation ( Fig. 14F, G View FIGURE 14 ) of inner peristomial margin well developed, sparse or absent. Interior view of orifice shows a pair of blunt condyles, one in each proximolateral corner. Multiporous spiramen ( Fig. 14C, G View FIGURE 14 ) in frontal depression, central in zooid or in distal half; mean length 96 μm, mean width 71 μm; spiraminal pores 2–6, mostly 4, varying a little in size and shape, each with 4–7 spokes of variable length, mostly short and not often touching. Spiramen becoming deeply sunken into a common furrow that includes the orifice and an avicularium as the frontal shield thickens ( Fig. 14E View FIGURE 14 ).

Adventitious avicularia ( Figs 13B, F View FIGURE 13 ; 14A, B, E View FIGURE 14 ) varying in size, position and orientation but all having same form, i.e. triangular rostrum with closed acute tip and smooth raised (gymnocystal) margins, common rostral-opesial foramen, semicircular opesial margin, smooth narrowly crescentic cryptocyst and no pivot bar; angles at rostralopesial transition constitute pivots. Suboral avicularia small, frequently paired, generally off-centre if single and an adjacent areola pore (source of avicularium) in place of second suboral avicularium; rostrum elevated obliquely frontalwards, generally directed a little obliquely outwards, sometimes pointing distally, distomedially if paired. Individual suboral avicularian cystids often sequentially budding additional avicularian cystids frontally to keep pace with secondary calcification. Ephebic zooids tend to have only one suboral avicularium, often displaced to a median position. A small adventitious avicularium commonly forming in a mid-proximal position as zooids age, directed obliquely distolaterally, transversely or proximolaterally; a similar avicularium less commonly distal to zooidal orifice, directed transversely or proximolaterally.

Marginal avicularia ( Fig. 13 View FIGURE 13 B–E) vicarious, subvicarious and interzooidal, fairly frequent, like adventitious zooidal avicularia but rostrum more elongate; vicarious and subvicarious avicularian cystids sometimes bearing a small adventitious avicularium.

Putative gonozooids ( Figs 13F View FIGURE 13 ; 17A View FIGURE 17 ) a little larger than autozooids, with larger spiramina having 7–8 pores, in one instance arranged in a circle.

Ancestrula and early astogeny not seen.

Remarks. Following Powell (1967), Adeonellopsis gemina n. sp. has generally been known in New Zealand as Adeonellopsis yarraensis ( Waters, 1881) , an early Miocene species from southwestern Victoria. Adeonellopsis yarraensis is lensoidal in cross section, however, not bilamellar, has only six series of autozooids across the branch width and the spiramen is at some distance proximal of the orifice, such that it becomes sunken separately in highly ephebic zooids, not in a common furrow with the orifice and a suboral avicularium. Harmer (1957) included several Recent species under the umbrella of A. yarraensis , including Adeonellopsis pentapora Canu & Bassler, 1929 , first described from the Philippines and Japan (see also Gordon 1993), and Gordon et al. (2009) used the combination A. pentapora for the New Zealand species. Hirose (2016) has thoroughly redescribed A. pentapora , however, and, although the two species are very similar, they differ in consistent small respects, e.g. A. pentapora typically has more spiraminal pores, a relatively large boss or tubercle near each lateral zooidal angle, an extra frontally adventitious avicularium, no marginal vicarious or subvicarious avicularia and no gonozooids or putative gonozooids.

Adeonellopsis gemina n. sp. also occurs as fossil fragments ( Fig. 14D View FIGURE 14 ) in the Castlecliffian (Pleistocene) Tainui Shellbed exposed near Castlecliff, Whanganui. Colony and zooidal characters ( Fig. 14E, G View FIGURE 14 ) are the same as the Recent material, spiramina are identical and the inner rim of the peristomial orifice ( Fig. 14G View FIGURE 14 ) also has denticulation in some zooids.

Distribution. Norfolk Island (Australian EEZ): Norfolk Island shelf, 290 m. New Zealand: Three Kings Islands, Greater Cook Strait, Kaikoura, Banks Peninsula, Canterbury shelf, Otago shelf, Fiordland (Doubtful Sound), Puysegur Bank, Snares Islands shelf; 32– 604 m. Also Pleistocene, Whanganui, New Zealand.

NIWA

National Institute of Water and Atmospheric Research

Kingdom

Animalia

Phylum

Bryozoa

Class

Gymnolaemata

Order

Cheilostomatida

Family

Adeonidae

Genus

Adeonellopsis

Loc

Adeonellopsis gemina

Liow, Lee Hsiang & Gordon, Dennis P. 2020
2020
Loc

Adeonellopsis pentapora:

Gordon 2009: 290
2009
Loc

Adeonellopsis yarraensis:

Gordon 1984: 73
1984
Loc

Adeonellopsis yarraensis:

Powell 1967: 337
1967
Loc

Adeonellopsis coscinophora var. mucronata:

Livingstone 1929: 91
1929
Loc

Adeonellopsis pentapora

Canu & Bassler 1929
1929
Loc

Microporella yarraensis

Waters 1881
1881
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