Schizocoryne polyfusa, Hayward & Winston, 2011

Hayward, Peter J. & Winston, Judith E., 2011, Bryozoa collected by the United States Antarctic Research Program: new taxa and new records, Journal of Natural History 45 (37 - 38), pp. 2259-2338 : 2300-2304

Schizocoryne polyfusa sp. nov.

( Figure 19 )

Material

Holotype. NMNH 1154049 : Eltanin cruise 11, station 974, 53 ◦ 32’ to 53 ◦ 34’ S, 64 ◦ 57’ to 64 ◦ 55’ W, 119–124 m, 12 February 1964; encrusting gravel.

Paratypes. Eltanin cruise 22, station 1595, 54 ◦ 40’ to 54 ◦ 39’ S, 57 ◦ 05’ to 57 ◦ 07’ W, 124– 128 m, 14 March 1966; two colonies encrusting gravel, one encrusting a shell fragment.

Other material. Eltanin cruise 9, station 740, 56 ◦ 06’ to 56 ◦ 07’ S, 66 ◦ 19’ to 66 ◦ 30’ W, 494– 384 m, 18 September, 1963; one colony on gravel (figured).

Description

Autozooids more or less oval, as broad proximally as distally, steeply convex. Primary orifice as wide as long, anter more or less semicircular; poster broadly triangular, with a frontal lip defining a short, U-shaped sinus comprising about one-fifth proximal width; proximo-lateral borders of poster constitute broad condylar processes. Eleven spines closely spaced around distal and lateral borders of orifice, long, thick and blunt, with brown, chitinous, basal articulation arising from ring-like socket. Frontal shield thickly calcified, finely granular, imperforate except for a peripheral series of small round pores that represent a series of small pore chambers within the thickness of the lateral walls. Ovicell hyperstomial, recumbent on distally succeeding autozooid, ovoid, not closed by zooidal operculum; with exposed area of entooecium frontally but otherwise imperforate (?). Rather flat, irregularly shaped and sized kenozooids are interspersed with the autozooids. Ancestrula tatiform, oval, with opesia occupying ca 60% of total length, bordered by an undetermined number of spines (> 10).

Measurements

For all measurements, n = 12, mean ± SD: autozooid length 1.04 ± 0.11 mm; autozooid width 0.73 ± 0.06 mm; orifice length 0.20 ± 0.01 mm; orifice width 0.20 ± 0.01 mm.

Etymology

Greek, poly: many; Latin, fusus: spindle, with reference to the numerous, fusiform oral spines.

Remarks

The material is limited to just five tiny colonies, encrusting very small substrata.

Two ancestrulae were present in the samples, but both were damaged and ancestrular morphology is therefore incompletely known. Similarly, only one ovicell was present but it was damaged in preparation and whether or not the frontal surface is perforated is not known. The broken frontal shield of one autozooid revealed a conspicuous umbonuloid frontal membrane, and the boundary between distal, umbonuloid and proximal, cryptocystal portions of the frontal shield could be discerned. However, shortage of material precluded further preparation and SEM examination, which would of necessity have been destructive.

Superfamily SCHIZOPORELLOIDEA Jullien, 1888 Family GIGANTOPORIDAE Bassler, 1935

Gigantopora spathula sp. nov.

( Figure 20 )

Material

Holotype. Eltanin cruise 9, station 740, 56 ◦ 06’ to 56 ◦ 07’ S, 66 ◦ 19’ to 66 ◦ 30’ W, 494– 384 m, 18 September 1963; fragment 16 mm long.

Paratypes. Same data as holotype; numerous fragments representing an undetermined number of colonies.

Description

Colony attached by an encrusting base, erect, cylindrical and branching; brittle, colony architecture unknown, the single sample comprised c.50 fragments, to about 18 mm long, from an unknown number of colonies. Autozooids in three to seven alternating longitudinal series, around the whole periphery of the branch; elongate oval, convex, bounded by distinct ridges, indicating vertical walls. Primary orifice almost terminal, as wide as long; anter gently arched, poster shallowly concave between small, rounded condyles. Peristome developed in earliest ontogeny, transversely oval in section, elongate, projecting at 45 ◦ to branch axis, its terminal aperture with pronounced distal and proximal lobes, and deep lateral notches. Proximally, the peristome forms a projecting, cap-like lobe above an extensive pseudospiramen through which the proximal edge of the primary orifice is visible. Paired peristomial avicularia present, the cystid of each budded close to lateral border of orifice; rostra curving medially and meeting at midpoint of proximal lip of peristome, each resembling a dipping ladle; crossbar stout, complete, with a small, rounded palatal foramen just distal to it; mandible sharply hooked. Frontal shield of autozooid lightly calcified, translucent, evenly and densely perforated by small, round pores; a single series of large marginal areolae bordering each autozooid; peristome imperforate but more thickly calcified than frontal shield and with irregularly nodular surface. Ovicell hemispherical, prominent, evenly perforated between nodular calcification, opening deep within the peristome. Vertical wall with numerous small uniporous septula.

Measurements

For both measurements, n = 20, mean ± SD: autozooid length (including peristome) 1.79 ± 0.13 mm; autozooid width1.11 ± 0.12 mm.

Etymology

Latin, spathula : spade, referring to the rostrum of the avicularium.

Remarks

Species of Gigantopora have been described from numerous localities in the southern hemisphere, and from Tertiary horizons in New Zealand. Gigantopora foraminosa Hayward and Cook, 1983 , from South Africa, and G. oropiscis Gordon and d’Hondt, 1997 , from New Caledonia, are also characterized by erect, cylindrical and branching colonies. In the former the peristomial complex incorporates short, paired avicularia with sharply pointed, medially directed rostra, and the pseudospiramen is hooded by a narrowed lobe linked to the peristomial bridge by a slender ridge. The peristomial complex of G. oropiscis is similar to that of G. spathula sp. nov., with a broad lip overhanging the pseudospiramen, and with both peristome and avicularia projecting frontally. Gigantopora oropiscis is distinguished from G. spathula in having smaller avicularia, with triangular rather than spathulate rostra, and by its proportionately shorter peristome, and coarser perforation. The ovicell of G. spathula is proportionately larger than that of G. oropiscis with more regular perforation.

Figures

Figure 19. Schizocoryne polyfusa sp. nov, Eltanin (9) stn. 740. (A) Group of autozooids and kenozooids, and the ancestrula; (B) detail of primary orifice. Scale bars: 0.5 mm (A), 0.1 mm (B).

Figure 20. Gigantopora spathula sp. nov., Paratype. (A) Autozooids in lateral view; (B) detail of a primary orifice, between the bases of the peristomial avicularia; (C) distal view of an ovicell; the avicularian rostra and the proximal edge of the peristome are broken short; (D) an undamaged peristome, with avicularium complete. Scale bars: 0.1 mm.