Ascidians of New Zealand. Part VIII Ascidians of the East Cape Region

Transactions and Proceedings of the Royal Society of New Zealand, Volume 80, 1952, Page 187

Ascidians of New Zealand. Part VIII Ascidians of the East Cape Region By Beryl I. Brewin., University of Otago [Read before the Otago Branch, September 11, 1951; received by the Editor, September 25, 1951] Summary Twenty-three ascidians are recorded from the East Cape region of New Zealand. Full descriptions are given of Aplidium novae-zealandiae n.sp., Sycozoa sigillinoides Lesson, Metandrocarpa protostigmata Michaelsen and Pyura spinossissima Michaelsen. The latter previously described as a variety of Pyura pachydermatina Herdman is raised to specific rank. In a note on P. pachydermatina it is shown that the geographical distribution of this species is less extensive than was previously thought, the Australian specimens so designated having been wrongly identified and P. spinossissima filling the same niche in the North Island of New Zealand. Michaelsen (1922, 1924) records eight ascidians from the East Cape region, four collected by the Mortensen Expedition, and four in the Berlin Museum collection (Thilenius Legacy). The list given below includes species collected by the author from intertidal rocks and wharf piles at Cape Kidnappers (K), Napier (N), and Tauranga (Tau), as well as those described by Michaelsen (m). List of Species Synoicidae Locality Aplidium thomsoni Brewin K, Tau * Species not hitherto recorded from New Zealand. Aplidium novae-zealandiae n.sp. Tau Didemnidae Didemnum candidum Savigny N, K Didemnum albidum (Verrill) (m) Tau, Mahia Diplosoma macdonaldi Herdman N Polycitoridae Polycitor (Eudistoma) circumvallatum (Sluiter) K Sycozoa sigillinoides Lesson N Distaplia fasmeriana Michaelsen K Rhodosomatidae Corella cumyota Traustedt (m) N, K, Mahia, Tau Botryllidae Botryllus leachi Savigny (m) Tau Botryllus magnicoecus (Hartmeyer) (m) Tau Styelidae † Species not in the present collection. Okamia thilenii (Michaelsen) (m) Tau Metandrocarpa protostigmata Michaelsen N Asterocarpa cerea (Sluiter) N, K, Tau Asterocarpa coerulea (Q. and Gaim.) Tau Cnemidocarpa nisiotis (Sluiter) N † Cnemidocarpa novae-zelandiae Michaelsen (m) Tau Cnemidocarpa bicornuata (Sluiter) N, Tau

Pyuridae Pyura subuculata (Sluiter) N, Tau Pyura suteri Michaelsen Tau Pyura cancellata Brewin N, Tau Pyura spinossissima Michaelsen (m) N, K, Tokuma Bay Molgulidae Molgula mortenseni (Michaelsen) (m) N, K The ascidian fauna of the Napier wharf piles is not only rich in species, but also remarkable for size attainments. Specimens of Cnemidocarpa nisiotis, Cnemidocarpa bicornuata, Pyura subuculata and Pyura cancellata all fall within or exceed the larger size range for those given in previous papers of this series and 75 per cent. of the specimens of Corella eumyota are of the giant proportions recorded in other localities for isolated specimens only (Sluiter, 1906; Arnback-Christie-Linde, 1938, Brewin, 1946). The maximum range of variability for these five species now reads as follows: Corella eumyota: length, 14 cm., breadth, 5·5 cm., depth 3.5 cm., distance of apertures, 10 cm.; branchial siphon, 4.7 cm. long, 1·0 cm. wide; atrial siphon, 1·5 cm. long, 1·0 cm. wide; test, 3·0 mm. thick; tentacles, 115 of 4 orders of size; longitudinal vessels, 110 on right; dorsal lamina of 200 languets, those in eight specimens being 3 or 4 rows deep near the oesophageal opening. Cnemidocarpa nisiotis: length, 6.0 cm., breadth, 3·0 cm., depth, 4.7 cm.; distance between apertures, 4·0 cm; tentacles, 54; longitudinal vessels, 98 on right; gonads may be missing on right. (Note: In December, 1949, the majority of the gonads were ripe and of the crenulated type depicted by Sluiter, 1900.) Cnemidocarpa bicornuala: length, 5.6 cm., length of gut loop seven-tenths that of body length. Pyura subuculata: length, 4.5 cm., breadth, 3.0 cm., depth, 2.8 cm.; gonad lobes, 50 on right, 42 on left; longitudinal vessels, 145 on right, 137 on left, arrangement on right E—(13)2(18)2(17)2(24)2(21)2(19)1(21)1DL. Pyura cancellata: length, 4.7 cm, breadth, 3.0 cm., depth, 3.5 cm.; branchial tentacles, 40; stigmata per mesh, 8; a rudimentary eighth pharyngeal fold present in a few specimens. Full descriptions are given of genera and species not appearing elsewhere in this series, the range of variability only being given for the rest. Specimens of Aplidium thomsoni, Didemnum candidum, Diplosoma macdonaldi, Polycitor (Eudistoma) circumvallatum, Distaplia fasmeriana, Corella eumyota (K, Tau), Botryllus leachi, and Pyura suteri, all fall within the range of variability given for Otago specimens as also do specimens of Pyura cancellata (Tau) except for the presence of lobate outgrowths on both inner and outer sides of the intestine. These structures were present in 70 per cent. of the specimens and were much more irregular in shape and arrangement than the “problematical organs” of Pyura pachydermatina (Brewin, 1946). Specimens of Didemnum albidum, Botryllus magnicoecus, Asterocarpa cerea, Cnemidocarpa bicornuata (Tau), Pyura subuculata (Tau) fall within the range given for the Hauraki Gulf specimens as also do those of Asterocarpa coerulea except for one 3.0 cm. long with a vessel count E 4(8)4(14)4(15)4(13)–D.L., total 66, and those of Molgula mortenseni except for one with 8 plicated folds and a vessel count E 4–4–5–6–7–7–8–5—D.L., total 46.

Description of Species Family Synoicidae Hartmeyer, 1908 Genus Aplidium Savigny, 1816 Aplidium novae-zealandiae n.sp. (Text-fig. 1 A, B) Colonies (Text-fig. 1 B), aggregations of flat-topped lobes, up to 1·5 cm. wide, 1·2 cm. in height above the substratum. Test colourless, transparent, with numerous small test cells and a few bladder cells, impregnated with sand except above the system of zooids. Zooids scarlet (pigmentation lost in formalin), in circular systems of 8–10, several systems to one lobe. Common cloacal apertures elliptical, 1 mm. in longest diameter, 3 mm. or more apart. Zooids (Text-fig. 1 A) up to 6·5 mm. long, 1 mm. wide in pharyngeal region, which has 14 longitudinal muscle bands, 12–14 fine transverse. Post-abdomen one-third body length, musculature concentrated on ventral side. Branchial aperture 6-lobed, atrial with tripartite lappet of which side lobes are nearly as large as the medium one. Pharynx with 32 tentacles of 3 orders of size. Dorsal lamina, 11 to 13 curved languets. On each side 14 to 15 rows of 12 to 14 stigmata, 3 or 4 times as long as wide, parastigmata absent. Oesophagus long, narrow; stomach short, with 4 to 5 longitudinal folds, halfway down post-abdomen; intestine wide, without marked constrictions; anal aperture smooth-edged. Twelve to 26 testis blocks in posterior half of post-abdomen. Ovary anterior to testis. Tadpoles up to 1.4 mm. long, 0.3 mm. wide in head region, as many as 13 present in mantle cavity, December 10, 1949. Distribution: Tauranga Harbour (on seaweed holdfasts). Remarks: No members of this genus recorded from Australia, South America or the Antarctic are identical with A. novae-zealandiae, and of the four species recorded from New Zealand which have but few (4–6) stomach folds, A. circumvallatum bears the closest resemblance to it, but is separated from it by the position of the ovary and the number of stigmata per row. Type in the Otago Museum. Family Polycitoridae Michaelsen, 1904 Genus Sycozoa Lesson, 1830 (as emended by Michaelsen, 1924) Colony with long hard stalk. Branchial aperture 6-lobed, atrial with lappet. Pharynx with 4 rows of stigmata, no parastigmata. Stomach Text-fig. 1. Aplidium novac-zealandiac. (A) Left side of zooid. × 42. (B) Portion of colony. × 1.

smooth-walled. Intestinal gland without vesicle. Colonies of separate sexes. Brood pouch present, containing several embryos. Sycozoa sigillinoides Lesson, 1830. (Text-fig. 2 A, B, C) For Syn. see: 1945, Sycozoa sigillinoides. Van Name, Bull. Amer. Mus. Nat. Hist., vol. 84, p. 151. Colonies capitate (Text-fig. 2 C), in life flesh-coloured or yellow, some with small mauve flecks. Head spherical, ovate or pear-shaped, slightly compressed laterally; length 0·5 to 0.8 cm.; breadth, long diameter 0·5 to 1·0 cm., short diameter 0·3 to 0·7 cm.; with zooids in longitudinal rows and with oval common cloacal apertures up to 1 mm. in diameter, 3 to 5 mm. apart, confined to the distal region of the head. Stalk round, firm, 1·8 to 5·0 cm. long, 0·2 to 0·5 cm. wide, simple, bifurcated or much branched (Text-fig. 2 C, 1, 2, 3, 4, 5), occasionally incrusted with hydroids. Zooids (Text-fig. 2 A, B) up to 4 mm. long (2 mm. being vascular process), up to 1 mm. wide in pharyngeal region, which has 18 or more fine longitudinal muscle bands. Rectaloesophageal region short. Abdominal region narrower than pharyngeal, vascular process arising from left side. Branchial aperture with 6 short lobes, atrial with lappet. Text-fig 2—Sycozoa sigillinoides. A. Zooid from female colony × 24. B. Zooid from male colony. × 24 C. 1, 2, 3, 4, 5. Colonies showing various degrees of branching—C2 with newly formed heads, no zooids visible. Pharynx with 16 branchial tentacles of 2 or 3 orders of size regularly arranged. Dorsal lamina of 3 languets. On either side 4 rows of 16 stigmata, 4 to 6 times as long as wide, no parastigmata. Oesophagus short; stomach smooth-walled, intestinal gland without reservoir; anal aperture smooth-edged. Colonies unisexual. Gonads in posterior end of intestinal loop, testis a rosette of 6 to 9 lobes (Text-fig. 2 B), ovary with 8 or more ova (Text-fig. 2 A). Brood pouch present in specimens collected August, 1950, long, sausage-shaped with slight spiral coiling and containing many embryos. Largest tadpole (not free-swimming) 2.0 mm. long, 0·5 mm. wide in head region, no buds visible. Distribution: In New Zealand: exact locality not known (Michaelsen), Napier. Elsewhere: from most parts of the Southern Hemisphere. Remarks. The species belonging to the genus Sycozoa are, on the whole, imperfectly described. Thanks to A.-C.-Linde's account (1950) of S. ramulosa Herdman, that species can be readily distinguished from S. sigillinoides by the brood

pouch, which in the former is short and contains at most three eggs. S. umbellata Michaelsen, however, is still not fully described. One form has already been referred back to S. sigillinoides by Michaelsen (1924). An umbellate form (Text-fig. 2 C, 4, 5) is characteristic of some of the specimens of S. sigillinoides in this collection. However, until more is known of S. umbellata it would be unwise on present evidence alone to incorporate it in S. sigillinoides. Family Styelidae Sluiter, 1895 Genus Metandrocarpa Michaelsen, 1904 (as emended by Michaelsen, 1922) Compound styelids with zooids more or less closely placed on a basal membrane or connected by stolons. Pharynx without folds, with 5 to 10 low longitudinal vessels. Polycarps mostly unisexual, male and female on either side, female anterior, occasionally two polycarps of different sexes fused. Metandrocarpa protostigmata Michaelsen (Text-fig. 3 A. B. C.) Syn.: 1922, Metandrocarpa protostigmata, Michaelsen, Vidensk Medd. naturh. Foren, bd. 73, pp. 461–469. Colonies small, irregular in outline, up to 2.5 cm. long, on tests of Corella eumyota and Cnemidocarpa nisiotis. Zooids orange to slate in colour, round or Text-fig. 3—Metandrocarpa protostigmata. A. Dissection showing body opened from ventral surface, pharynx removed. × 2. B. Tadpole. × 30. C. Small colony on test of simple ascidian. × 2. oval, 0·5 to 3·2 mm. long (3.6 mm, Michaelsen), 0·5 to 2·5 mm. wide, dorsoventrally compressed, 0.3 to 1.0 mm. deep, each with a thin, narrow encircling basal membrane (Text-fig. 3 C) permeated by vessels ending in enlarged bulbs. Zooids separated by distances of up to 2·3 mm. and connected by stolons 0·5 to 1·9 mm. wide, 0·1 mm. deep. Siphonal apertures at equal distances from centre of top surface, 0.3 to 1·1 mm. apart. Test 20 to 50μ thick, free from sand. Mantle musculature well developed. Pharynx with 16 tentacles of at least 2 orders of size, irregularly arranged [20, with arrangement 13231 or 12121 (Michaelsen)]; dorsal tubercle small, oval, with slit-like aperture; dorsal lamina plain membrane; on each side 6, 7, or 8 longitudinal vessels; 10 to 11 rows of stigmata on right, 7 on left, where posterior third is occupied by long “protostigmata” (Michaelsen, 1922, p. 466, fig. 30), stigmata six times as long as wide with parastigmatic vessels, 22 to 32 per row, arrangement of type D.L. 2–4/2/2/2/3/2/2/5–15 E. Oesophagus very short; stomach cone-shaped or globular, slightly longer than wide, with 16 to 18

folds and a short strongly curved caecum; intestine smooth, curved; anal aperture faintly bi-lobed. Endocarps (Text-fig. 3 A) 8 to 15, small, on both sides of body. Atrial tentacles small, in single row. Gonads (Text-fig. 3 A), polycarps with short gonoducts, male a single testis lobe, female anterior to male with 1 to 5 ova. Arrangement: right, 4 to 6 female, 0 to 2 male, 0 to 1 hermaphrodite; left, 3 to 5 female, 2 to 3 male, 1 to 2 hermaphrodite. [Right, 7 female, 2 male, 3 hermaphrodite; left, 7 female, 17 male, 1 hermaphrodite (Michaelsen)]. Tadpoles (Text-fig. 3 B) in mantle cavity (December, 1949), large orange, up to 11 in all stages of development in one specimen. Largest 2 mm. long, 0.5 mm. wide in head region. Distribution: Hauraki Gulf (Michaelsen), Napier (on wharf piles). Remarks: Examination of co-types kindly loaned by University Museum, Copenhagen, proved conclusively that the Napier specimens belong to the species M. protostigmata Michaelsen. Family Pyuridae Hartmeyer, 1908 Genus Pyura Molina, 1782 Notes on Pyura pachydermatina Herdman. The original description of this species (Proc. Roy. Soc. Edin., 1880) was from two adult specimens from Canterbury, South Island, New Zealand. Subsequently the same species has been recorded in New Zealand from Stewart Island, Canterbury (Sumner) [Michaelsen], Otago Harbour [Watt], Otago Harbour, Canterbury (Lyttelton, Taylor's Mistake) [Brewin]—all localities being in the South Island. Michaelsen's var. spinossissima (1922), recorded from Cape Kidnappers, North Island, occurs in the present collection and is in this paper raised to specific rank. P. pachydermatina, however, has not so far been found by the author anywhere in the North Island. It would thus seem that P. pachydermatina is confined to the South of New Zealand, P. spinossissima to the North. A point worthy of recording is that long-period field observations have shown that the juvenile form differs from that of the adult in both P. pachydermatina (Watt, 1892; Brewin, 1946) and in P. spinossissima (Brewin) (Plate 37, figs. 1, 2, 3, 4). Herdman (1899) in “Descriptive Catalogue of Tunicata in the Australian Museum” placed some Australian specimens from New South Wales in the species P. pachydermatina. On the grounds of geographical distribution, the author queried this and, thanks to the kindness of the directors and staff of the Australian Museum and of the Cronulla Fisheries Research Laboratory, has been able to re-survey Herdman's material and to collect fresh material from the New South Wales coast. It is apparent that Herdman was dealing with small pickled specimens of a purely Australian species, which differs from P. pachydermatina in colour, form (having a flattened distal end to the head, two enlarged lateral lobes to the atrial aperture, one enlarged median lobe to the branchial aperture), number and shape of gonad lobes, number of stigmata per mesh, shape of the anal aperture, and in not having a very markedly different juvenile form. Thus the distribution of P. pachydermatina is less extensive than was previously thought, it being a purely New Zealand form and probably confined to the South Island and Stewart Island. Note: Michaelsen (1922) having examined Sluiter's specimens of C. lutea from the Chatham Islands, made C. lutea a

synonym of P. pachydermatina, but as he had been misled by Herdman and Sluiter's type material is not available, it would be well advised at present to restrict P. pachydermatina to known localities until Chatham Island material has been resurveyed. Pyura spinossissima Michaelsen (Plate 37, figs. 1–10) Syn.: 1914, Pyura pachydermatina Herdman var. spinossissima Michaelsen, Michaelsen, Vidensk. Medd. naturh. Foren., bd. 73, pp. 389–399. Body large, ovate, somewhat laterally compressed, elongate in antero-posterior direction, attached to substratum anteriorly by long leathery stalk. Head region with tubercles (average number 160) which in juvenile specimens are narrow, pointed, up to 7.5 mm. long, 2 mm. wide at base (Plate 37, fig. 1), in medium-sized specimens are more rounded, and in fully grown specimens are large, rounded, up to 12 mm. long, 14 mm. wide at the base and often show fusion between the bases of adjoining ones (Plate 37, fig. 2). In juvenile specimens marked longitudinal ridging of the test so characteristic of P. pachydermatina (Plate 37, figs. 3, 4) does occur, but tubercles cover the sides as well as the summits of the ridges and also occur in the grooves, and even on the adjoining region of the stalk. Test leathery; purple externally except at the end of the tubercles, where it is pink in small specimens, yellow in large; pearly white internally; with numerous test cells, blood vessels, and in the outer layer pigment cells and calcareous spicules up to 0.071 mm. long (Plate 37, fig. 10). Branchial siphon opening towards stalk, atrial distally, one side of each formed by body itself; folds around aperture 2 to 4 approximately equal in size, difficult to distinguish because of tubercles. Siphonal spinules (Plate 37, fig. 9) up to 0.058 mm. long, 0.018 mm. wide. Incrustations almost confined to stalk, hydroids, bryozoa, simple and compound ascidians. Measurements based on the study of 25 specimens are: length 3·2 to 10 cm.; breadth 1·5 to 4·0 cm.; depth 2·0 to 5·4 cm.; stalk, 17 to 40 cm. long (average length 30 cm.), 0·3 to 0·4 cm. wide near attachment, 0·6 to 0 8 cm. wide near head; distance between apertures, 1.3 to 4·5 cm.; branchial siphon, 0.8 to 1.2 cm. long, 0.9 to 1·4 cm. wide; atrial siphon, 0.8 to 1.1 cm. long, 0.7 to 1·2 cm. wide; thickness of test, 1.0 to 1.5 mm. (up to 12 mm. in tubercles). Mantle tough, with strong circular muscles around siphons and strong longitudinal muscle bands radiating out from siphonal region, semi-transparent except for opaque extensions of testis over anterior end of body and most anterior gonad lobes in small specimens, and extending posteriorly and laterally in larger specimens (Plate 37, fig. 5). Pharynx with 24 to 32 feathery tentacles [one specimen with 12 (Michaelsen, 1922)] of 3 orders of size regularly arranged, 3 to 5 orders of branching (usually 4); opening of dorsal tubercle as shown in Plate 37, fig. 8, more complex foldings occurring in larger specimens; neural gland small, oval, beneath and slightly to left of nerve cord; dorsal lamina 25 to 55 short, curved languets; on each side 6 longitudinal folds; longitudinal vessels 82 to 144 on right, 87 to 138 on left, arranged thus: Length of Specimen Arrangement of Vessels on right Total 4·2 cm. E 3(8)2(12)2(12)2(12)2(13)2(10)2D.L. 82 5·0 cm. E 6(10)3(12)3(15)2(18)3(17)2(16)2D.L. 109 7·0 cm. E 3(9)2(17)3(16)3(18)3(19)3(17)2D.L. 115 10·0 cm. E 6(16)3(18)3(20)4(22)3(24)2(20)3D.L. 144

Transverse vessels irregularly arranged, 3 to 8 between 2 large. Stigmata straight, 4 times as long as wide, 12 to 16 in meshes between the folds, parastigmata present. Gut loop (Plate 37, fig. 1) occupying practically whole length and more than half width of left side of body. Oesophagus narrow. Little difference in width between stomach and intestine, the latter bearing “problematical organs” on second half of loop. Five pairs of liver lobes, largest nearest intestine, smallest adjacent to it. Anal aperture wide, smooth-edged and hooded. Atrial velum frilled, 3 to 4 mm. wide, edge scalloped. Gonads, on each side, with 8 to 14 (average number 11) somewhat irregularly shaped hermaphrodite lobes arranged in a single row (Plate 37, fig. 6), smallest nearest gonoduct openings, i.e., nearest to atrial aperture. Gonads distended early December, 1949. Distribution: In New Zealand: Cape Kidnappers (Michaelsen), Napier, Cape Kidnappers. Remarks: Michaelsen (1922) described small and medium-sized specimens of the species described above as P. pachydermatina var. spenossissima. Having studied a wide range of specimens from the same locality and also of P. pachydermatina from various localities, the author has decided to raise the variety to specific rank. The following differences are notable between it and P. pachydermatina: (1) Greater number and more irregular distribution of tubercles on the test of small specimens (Plate 37, figs. 1, 3). (2) Persistence of numerous large tubercles in fully grown ones (Plate 37, figs. 2, 4). (3) Greater number of stigmata per mesh 12 to 16 (7 to 9, P. pachydermatina). (4) Smaller number of longitudinal vessels between folds in larger specimens—maximum 4 (6 to 7, P. pachydermatina). (5) More irregular shape of gonad lobes. (6) Greater extension of gonad over the mantle wall. [Watt (1892) describes slight extension in P. pachydermatina, stating that in structure it resembles an aggregation of unripe ova. Here it is definitely testis extension.] (7) Geographical distribution and the absence of intermediate forms. Note: As in P. pachydermatina a great amount of change occurs as growth proceeds, not only in external appearance but also in the shape of the opening of the dorsal tubercle and in the number of longitudinal vessels. P. spinossissima is not identical with any of the stalked species found in Australian waters. Commensals Amphipods in branchial sac of Corella eumyota, Asterocarpa cerea, Cnemidocarpa nisiotis, Cnemidocarpa bicornuata, Pyura spinossissima, Molgula mortenseni. Copepods of family Notodelphidae in Asterocarpa cerea, Cnemidocarpa nisiotis, Cnemidocarpa bicornuata, Pyura subuculata, Pyura suteri. Several small barnacles and a piddock in test of Corella eumyota (N) and Cnemidocarpa nisiotis (N). Suctorians present on the branchial tentacles of some specimens of Sycozoa sigillinoides. Tadpoles Present in Aplidium novae-zealandiae, Metandrocarpa protostigmata and Asterocarpa cerea early December, 1949, and in Sycozoa sigillinoides August, 1950.

Fig. 1—Young specimen of Pyura spinossissima × 1 Fig. 2—Fully grown specimen of P. spinossissima × ½ Fig. 3—Young specimen of Pyura pachydermatina × 1 Fig. 4—Fully grown specimen of P. pachydermatina × ½ Fig. 5—Right side of mantle of P. spinossissima showing musculature and testis extension × ½ Fig. 6—P. spinossissima Dissection showing body opened from ventral surface pharynx removed × 3/4 Fig. 8—Dorsal tubercle of P. spinossissima × 5 Fig. 9—Siphonal spinules of P. spinossissima × 380 Fig. 10—Calcareous spicules from test P. spinossissima × 380.

References These include all those given in previous papers of this series as well as: Arnback-Christie-Linde, A., 1950. Ascidiacea, Part II. Further Zool. Res. of Swed. Ant. Exped., 1901–1903, vol. 4, no. 4, pp. 1–41. Brewin, B. I., 1952 Ascidians from Otago Coastal Waters, Pt. 2. Trans. Roy. Soc. N. Z., vol. 79, pp. 452–458. Herdman, W. A. Prelim. Rep. on Tunicata of Chall. Exped. Proc Roy. Soc. Edin., 1880–1881, vol. 11, pp. 52–88.