Some Alcyonaria of the Order Stolonifera from New Zealand Waters, with the Description of One New Species

Transactions and Proceedings of the Royal Society of New Zealand, Volume 75, 1945-46, Page 29

Some Alcyonaria of the Order Stolonifera from New Zealand Waters, with the Description of One New Species By Beryl I. Brewin, University of Otago. [Read before Otago Branch, June 13, 1944; received by the Editor, July 24, 1944; issued separately, June, 1945.] The only member of the Order Stolonifera recorded in Hutton's Index Faunae Novae Zealandiae (7) is the species Anthopodium australe Verrill, which was found on a stem of Primnoella australasiae from Bluff Harbour (15). Since the date of publication of the Index, Clavularia thomsoni has been described by Sir William Benham (1). This species was found on a simple coral, collected in 1915, in Foveaux Strait by the Hon. G. M. Thomson while on board the G.S.Y. Hinemoa. The type specimen is in the Otago Museum. The present paper is an account of three Stoloniferans collected on the coastal rocks around Dunedin. As far as I can ascertain two have not been described previously, and the other is probably a small specimen of Anthopodium australe Verrill. Clavularia Quoy and Gaimard. Clavularia novae-zealandiae sp.n. The colonies are a light violet-brown and up to 18 square inches in area. The stolon consists of strands 1mm. or more in width, coalescing in places to form membranes up to 2 square cms. in area (Fig. 1). These adhere firmly to the surfaces of stones, oyster shells, etc., and never exceed 1.5 mm. in thickness. The polyps show a tendency to crowd on the membranes, but may be 6 mm. apart else-where. New polyps develop only in expanding portions of the stolon. There is a well marked division into anthostele (violet-brown and faintly ridged) and anthocodium (green-yellow, retractile). Upon retraction of the anthocodium, the anthostele does not present a markedly stellate appearance. The tentacles bear two rows of 16 pinnae. Of these the distal eight are usually held downwards and the proximal ones upwards. The five pinnae nearest the disc are mere stumps. The average length of the polyp in life is: anthostele, 4 mm.; anthocodium, 5 mm. The diameter of the anthostele is 1.5 mm. The skeleton of the anthostele and stolon consists of strong, heavily warted, colourless spindles (Fig. 5a), arranged in rows, and, as is typical in the genus Clavularia, those nearer the distal end of the anthostele are less heavily warted (Fig. 5b). The only skeleton of the anthocodium is in the form of small, curved spicules (Fig. 5c) in the tentacles and on the perimeter of the disc in between the tentacle bases (Fig. 8). Average Measurements of Spicules. Anthostele (proximal region and stolon) 0.28 mm. x 0.05 mm. Anthostele (distal region) 0.26 mm. x 0.028 mm. Anthocodium 0.088 mm. x 0.01 mm.

Zooxanthellae are very numerous in the endodermal cells. This species is fairly common in the Otago Harbour. I have collected many specimens from the Marine Biological Station point and from the channel sides of Goat and Quarantine Islands. Type specimen: Otago Museum. Affinities of the Species. C. novae-zealandiae varies from C. thomsoni Benham (1) both in the shape of the polyps and in the skeleton. Fig. 7a, b, c, shows the large and heavily warted spicules which form the extremely dense skeleton of C. thomsoni. Both specimens 1 and 2 of Hickson's C. australiensis Var. A (4) bear some resemblance to C. novae-zealandiae. Specimen 1 differs in that the polyps are partly retractile into the stolon and in the disposition of the warts of the spicules. Specimen 2 has long, tubercular processes on the spicules, and is found on sponges. C. novae-zealandiae has short, warty processes, and is found only on hard substrata—never on sponges, although they are abundant in the neighbourhood. C. violacea Quoy and Gaimard (11) differs in the size of the polyps, the number of pinnae, and in having a pigmented skeleton. None of the other littoral forms described by Dana (3), Hickson (4), (6), Thomson and Dean (13), Roxas (12), and MacFayden (9) bear any close resemblance to the species described above. Clavularia novae-zealandiae Brewin, var. nov. This stoloniferan occurs in the same localities as C. novae-zealandiae and often on the same boulders. It differs from C. novae-zealandiae in (1) absence of zooxanthellae, (2) absence of violet tint in anthostele and stolon, (3) a weaker form of growth (all measurements are slightly smaller than those of C. novae-zealandiae), (4) the spicules (Fig. 6), which are shorter than those of C. novae-zealandiae and slightly broader, although this may only be the result of slower growth in this variety. At present the writer is carrying out experiments at the Marine Biological Station, Portobello, in order to discover whether this is really a variety of C. novae-zealandiae or an entirely different species. The results of these experiments should be published by next year, but in the meantime it remains a variety. Description. The colonies consist of a brown network up to 10 square inches in area, the stolon being composed of fine strands, 1 mm. or more in width, which seldom coalesce to form membranes (Fig. 2). The largest membrane I have seen was ½ square cm. in area. The stolon does not exceed 1 mm. in thickness and develops only on hard substrata. The polyps usually arise singly about 3 mm. apart, but occasionally occur close together in pairs or in threes. New polyps develop on expanding portions of the stolon. There is a well-marked division into anthostele (brown, faintly ridged) and anthocodium (white, retractile). When the anthocodium is withdrawn the anthostele does not show a markedly stellate appearance. The tentacles resemble those of C. novae-zealandiae very closely. The average length of the polyp in life is: anthostele, 3.5 mm.; anthocodium, 3.5 mm. The average diameter of the polyp is 1.5 mm.

The skeletal disposition is the same as that of C. novae zealandiae, but measurements of the spicules differ (Fig. 6a, 6b, 6c). Average Measurement of Spicules. Anthostele (proximal region and stolon) 0.20 mm. x 0.06 mm. Anthostele (distal region) 0.20 mm. x 0.03 mm. Anthocodium 0.088 mm. x 0.01 mm. Zooxanthellae are absent. The distribution is as for C. novae-zealandiae. Type specimen: Otago Museum. Anthopodium Verrill. Anthopodium australe Verrill. The description of this species is based on one small specimen (Fig. 3), ½ square cm. in area, which was collected by Professor Marples on a small piece of shell in a crevice of rock at Taieri Mouth, an ocean beach 25 miles south of Dunedin. The stolon takes the form of an extremely thin membrane, ½ mm. in thickness. Five verruciform polyps are present, one of which is much smaller than the others. Four of the polyps touch one another at their bases, the fifth is somewhat isolated. In all five the anthocodia are retracted. The colour of the stolon and anthostele is a bright orange-red. Professor Marples describes the anthocodium in life as white, and the anthostele presents a while stellate appearance when the anthocodium is withdrawn. The average length of the polyps in the preserved state is 1.3 mm., and the diameter 1.5 mm. I have been unable to count the pinnae on the tentacles or to make observations on the skeleton of the anthocodium. The skeleton of the anthostele and stolon are small, orange-red spicules (Fig. 4). They are characterised by short, rounded tubercles, not arranged in rings in the manner of Clavularian warts. The spicules are closely arranged, but are not touching, and to them alone is due the orange-red colour on the stolon and anthostele. Average measurement of spicule, 0.14 mm. × 0.058 mm. Specimen, Otago Museum. Remarks. Verrill's description of the genus Anthopodium (14) his as follows:—“Coral with an incrusting firm coenenchyma, from which arise prominent tubular verrucae with rather large polyps at the summit. The surface of the coenenchyma and verrucae is minutely granular, with rough, irregular spicula closely united together. The spicula are of many forms and sizes, and remarkable for their irregularity and roughness; the most prominent kinds are very roughly warted, and spinulose oblong forms and rough, lacerate, club-shaped ones, many of which are flattened at the large end. Besides these there are numerous rudely spinulose spindles, and an abundance of the small, short, glomerate kinds.” The Taieri Mouth specimen agrees with the above description in having a firm, encrusting membraneous base, retractile anthocodia and tubular verrucae. The surface, however, is smooth, but appears granular owing to the fact that the minute orange-red spicules are

visible through the colourless epidermis. The spicules have irregular tuberculate processes, but are not closely united together as in the description. It is possible that this apparent union as described by Verrill may be due to insufficient separation of the spicules in maceration. I have not observed any of the lacerate club-shaped or spinulose spicules. Although the Taieri Mouth specimen does differ in a few respects from Verrill's account, it is more closely related to this genus than to any other, and it seems rather unnecessary to erect a new genus. Also Verrill's description of A. australe (15) agrees in many important respects with that of the Taieri Mouth specimen. For instance, in both, the polyps are cylindrical, with distinct sulcations at the summit in contraction; the colour is light orange-red; the surface is covered with small and rough spicules; the membraneous base is thin and encrusting; the diameter of the polyps is 1.5 mm. Verrill gives the height of the polyp cells as 2–6 mm., but he does not state whether these measurements are made on expanded or contracted specimens. On the specimen described above all measurements were taken from contracted polyps, the average height of which is 1.3 mm. The writer is of opinion that, until more material is collected the Taieri Mouth specimen should be included in A. australe. Unfortunately, the systematists working in this group—Hickson (15), Kukenthal (8), Molander (10), Roxas (13)—consider that the genus Anthopodium has been insufficiently described and have abandoned it. It is hoped that the collection and examination of further specimens may be sufficient to re-establish this genus. Literature. [1] Benham, W. B., 1929. On Some Alcyonarians from N.Z. Waters. Trans. N.Z. Inst., vol. lix, p. 67. [2] Bourne, G. C., 1914. On Acrossota liposclera. Quart. Journ. Micros. Sci., vol. ix. [3] Dana, J. D., 1848. U.S. Exploring Expedition: Zoophytes. [4] Hickson, S. J., 1895. A Revision of the Genera of the Alcyonaria Stolonifera, with a Description of One New Genus, and Several New Species. Trans. Zool. Soc., vol. xiii, p. 325. [5] —— 1930. Classification of the Alcyonaria. Proc. Zool. Soc. Lond., Pt. 1, p. 229. [6] —— 1930. Some Alcyonarians from the Eastern Pacific Ocean. Proc. Zool. Soc. Lond., Pt. 1, p. 209. [7] Hutton, F. W., 1904. Index Faunae Novae Zealandiae, p. 315. [8] Kukenthal, W., 1906. Alcyonacea. Ergeb. Deut. Tiefsee Exped., 13, 1. [9] Macfayden, L. M. I., 1935. Alcyonaria, Great Barrier Reef Exped. Sci., Rpt. 5. [10] Molander, A. R., 1918. Der Kelch als systematischer Charakter bei den Alcyonacein. Arkiv. Zool. 11. [11] Quoy and Gaimard, 1834. Voyage de decouvertes de “l' Astrolabe,” vol. 4, Zoophytes, p. 227. [12] Roxas, H. A., 1933. Phillipine Alcyonaria. Phillipine Journ. Sci., 50. [13] Thomson, A. J., and Dean, L. M. I., 1931. Alcyonacea of the Siboga Expedition. Monograph 13d. [14] Verrill, A. G., 1872. American Journal of Science and Arts, ser. 3, vol. iii, p. 435. [15] —— 1876. Bulletin of U.S. Nat. Museum, p. 76. [16] Wright and Studer, 1889. Report on the Alcyonaria, Challenger Reprots, vol. 31.

Plate 2. Trans. Royal Society of N.Z., Vol. 75. Fig. 1.—A portion of a colony of Clacularia novae-zealandiae showing thin, membrane-forming stolon and form of the polyps. Fig. 2.—A portion of a colony of Clacularia novae-zealandiae var. nov., showing thin. ribbon-like stolon. Fig. 3.—A shall colony of Anthopodium australe attached to a portion of shell. Fig. 4.—Spicules of Anthopodium australe. × 120. [Facing page 32.]

Trans. Royal Society of N.Z., Vol. 75. Plate 3. Fig. 5.—Spicules of Clavularia novae-zealandiae, × 120. Fig. 6.—Spicules of Clavularia novae-zealandiae var. nov., × 120. Fig. 7.—Spicules of Clavularia thomsoni, × 120. Fig. 8.—A portion of the oral region of Clavularia novae-zealandiae showing the position of the spicules.