Electronic Flora of South Australia Species Fact Sheet

Nitospinosa tasmanica Womersley, sp. nov.

Phylum Rhodophyta – Family Delesseriaceae

Thallus (Fig. 37A) medium to dark red-brown, 5–15 cm high, foliose with mid parts 0.5–8 cm broad, bearing smaller branches or ovate lobes 4–15 mm broad from the upper margin; margins dentate (Fig. 37B), with frequent short spines mostly 50–200 µm long; veins absent but mid thallus often perforate with small holes (from grazing?); lower thallus narrower and centrally slightly thickened, becoming stipe-like basally. Holdfast fibrous, 2–6 mm across; epilithic. Structure. Growth from the marginal dentations each with a transversely dividing apical cell (Fig. 37C), with axial and second-order cell rows recognisable only to the base of the spines; between the spines, some marginal cells divide by anticlinal walls; below the spines, cell rows scarcely recognisable (Fig. 37B, C), intercalary divisions frequent giving an irregular cell arrangement. Young blades monostromatic (Fig. 37D) and 40–55 µm thick, soon becoming tristromatic and centrally polystromatic (Fig. 37D) and then 130–180 µm thick; surface cells angular, 20–40 µm across and L/D 1–2, with the cortical cells equivalent to the slightly thinner primary cells. Cells multinucleate; rhodoplasts discoid.

Reproduction: Gametophytes dioecious. Procarps scattered, details not observed. Carposporophytes with a basal, erect, fusion cell and much branched gonimoblast with ovoid to shortly clavate terminal carposporangia 30–60 µm in diameter, the subterminal cells maturing rapidly to give short chains. Cystocarps (Fig. 37E) scattered, swollen, 1–1.5 mm across; pericarp ostiolate, 100–180 µm and 6–8 cells thick, cells tiered. Spermatangial sori (Fig. 37F) irregular in shape, 200–600 µm across, with the primary cells producing on each side a layer of initials which cut off elongate spermatangia.

Tetrasporangial sori (Fig. 37G) ovate, scattered, 200–450 µm across and 160–200 µm thick, with tetrasporangia in 2 layers, cut off from inner cells of 2–3-celled cortical filaments and covered by the outer cells; tetrasporangia subspherical, 45–75 µm in diameter.

Type from Arch Rock, off Ninepin Point, SE Tasmania, 1–10 m deep (Andrews, 21.x.1994); holotype in AD, A63908.

Selected specimens: The Rip, Port Phillip Heads, Westernport Bay, Vic., 16–21 m deep (Saunders, Strachan & Kraft, 5.iv.1995; MELU, K10623a and AD, A68265). Crawfish Rock, Westernport Bay, Vic., 5–10 m deep (Watson, 29.viii.1971; AD, A39375). West Point, Erith I., Bass Strait, 28 m deep (Shepherd & R. Lewis, 10.v.1974;AD, A45236). Low Head, Tas. (Perrin, 5.x.1950; AD, A16440). Bombay Rock, Tamar Est., Tas., upper sublittoral (Womersley, 27.i.1948; AD, A10359). Ninepin Point, Tas., 7–12 m deep (Edgar, 1.v.1999; AD, A68223). Arch Rock, E of Ninepin Point, SE Tas., 8–12 m deep (Barrett, 23.x.1994; AD, A63969, A63970). Charlotte Cove, near Ninepin Point, SE Tas., 3–6 m deep (Edgar, 6.x.1999; AD, A68327-"Marine Algae of southern Australia" No. 408).

Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution: Port Phillip Heads and Crawfish Rock, Westernport Bay, Vic., Low Head, N Tas., and Ninepin Point and Arch Rock, SE Tasmania.

Taxonomic notes: Nitospinosa tasmanica is distinct from N. pristoidea in morphology but shows the characteristic marginal dentations on young apices; these are often lost from older parts. N. tasmanica is named from its occurrence mainly in Tasmania.

References: The Marine Benthic Flora of Southern Australia Part IIID

Author: H. B. S. Womersley

Publication: Womersley, H.B.S. (24 February, 2003)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIID. Ceramiales – Delesseriaceae, Sarcomeniaceae, Rhodomelaceae
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIID 2003, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

Illustration in Womersley Part IIIA, 2003: FIG. 37.

Figure 37   enlarge

Fig. 37. Nitospinosa tasmanica (A, B, D, G, AD, A63908; C, AD, A63969; E, AD, A68223; F, AD, A 10359). A. Habit. B. Apex of frond with frequent spines. C. A spine with apical cell and segmentation below. D. Transverse sections of young and older thallus. E. Section of cystocarp. F. Spermatangial sori. G. Blade with tetrasporangial sori.

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