Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 79, 1951
This text is also available in PDF
(497 KB) Opens in new window
– 452 –

Ascidians of New Zealand. Part VII
Ascidians from Otago Coastal Waters. Part II

[Read before the Otago Branch, October 17, 1950; received by the Editor, October 25, 1950]

Summary

This paper gives an account of seven species of ascidians from Otago coastal waters. Two new genera have been established, Dumus in the Synoicidae, type species Dumus areniferus, and Berrillia in the Styelidae, type species Berrillia boltenioides. Two new species, Distaplia marplesi and Cnemidocarpa otagoensis, are described and a new depth record given for Cystodytes dellochiaiae.

The material which forms the basis of this paper was collected partly by Captain Black, of the trawler Taiaroa, from 40 to 50 fathoms off Oamaru, partly by the author from coastal rocks at Victory Beach, on the ocean side of the Otago Peninsula.

List of Species

Synoicidae
1.

Amaroucium oamaruensis Brewin

2.

Dumus areniferus n.sp.

Polycitoridae
3.

Cystodytes dellachiaiae Della Valle

4.

Distaplia marplesi n.sp.

Styelidae
5.

Berrillia boltenioides n.sp.

6.

Cnemidocarpa madagascariensis Hartmeyer var. regalis Michaelsen

7.

Cnemidocarpa otagoensis n.sp.

The specimens of Cystodytes dellachiaiae collected from 40–50 fathoms off Oamaru fall within the range of variability given for those from Hauraki Gulf (Brewin, 1948), but the depth is greater than that from which any New Zealand specimens have been recorded. Study of specimens of Amaroucium oamaruensis in this collection shows that the following additions should be made to the previous description: (1) the ovary lies immediately anterior to the testis and (2) a single stout atrial lappet may be present, though this is not the general rule.

Family Synoicidae Hartmeyer, 1908
Genus Dumus n.gen.

Synoicidae characterized by each zooid having a separate covering of test for its entire length, though portions of the tests of neighbouring zooids may be fused. Individuals united by a basal membrane. Apertures opening directly to exterior. Post-abdomen long, not separated from abdomen by a constriction.

Type of the genus: Dumus areniferus.

Note: This genus is distinguishable from Euherdmania Ritter, 1904, by (1) the fact that the zooids are not entirely isolated, portions of the

– 453 –

tests of neighbouring zooids being fused, (2) the long post-abdomen, (3) other features such as number of rows of stigmata, stomach folds, length of gut loop, etc., the genus Euherdmania having been very narrowly defined. It is distinguishable from Sigillinaria Oka, 1933, by the presence of a separate covering of test for the entire length of each zooid. Note: Zooids of Sigillinaria pulchra (Ritter) are peculiar in the genus in that they may occasionally have separate coverings of test, but only in the pharyngeal regions.

Dumus areniferus n.sp. (Text Fig. 1 A, B)

Colonies sandy thickets (Text Fig. 1 B) up to 30 cm. in longest diameter and 3·5 cm. in depth. Basal membrane, sandy, 1 mm. thick. Each zooid with a separate covering of test for its entire length, though portions of the test of neighbouring zooids may be fused.

Picture icon

Text Fig. 1 Dumus areniferus.
(A) Left side of zooid. × 30.
(B) Portion of colony. × 1.

Zooids (Text Fig. 1 A) yellow, up to 7 mm. long, 0·5 mm. wide in pharyngeal region, which has an overall network of fine longitudinal and transverse muscles. Post-abdomen up to 5 mm. long, musculature not concentrated on any one side. Branchial and atrial apertures opening separately to exterior, each with six small lobes.

Pharynx with 24 simple tentacles of 3 orders of size regularly arranged; dorsal lamina of 4 curved languets; on each side 4 rows of 15 to 17 stigmata up to five times as long as wide. No parastigmatic vessels.

Oesophagus short, narrow; stomach without folds; intestine wide; anal aperture smoothedged, straight.

Ovary of up to 10 eggs at various stages of development, in anterior portion of post-abdomen (Text Fig. 1 A). Testis of up to 17 lobes, posterior to ovary, occupying not more than half length of post abdomen. In specimens collected 22nd October, 1949, a few early embryos in mantle cavity.

Distribution: Otago coastal waters (intertidal, on rocks, Victory Beach).

Type specimen in the Otago Museum.

Family Polycitoridae Michaelsen, 1904
Genus Distaplia Della Valle, 1881
(as emended by Michaelsen, 1924)

Distaplia marplesi n.sp. (Text Fig. 2 A, B)

Colonies (Text Fig. 2 A) bright orange, flat, up to 5·7 cm. long and 3·5 mm. high, irregular in outline, with smooth rounded edges. Test orange in colour, transparent, with numerous small test cells. Zooids brilliant orange, arranged

– 454 –

in systems of 8 to 12 around the common cloacal apertures, which are circular in outline, up to 1 mm. in diameter and 2 to 4 mm. apart.

Zooids (Text Fig. 2 B) up to 2·3 mm. long and 1·2 mm. wide in pharyngeal region, which has 18 very fine longitudinal muscle bands, 4 transverse. Rectal-oesophageal region short and abdominal region almost equal in width to pharyngeal. Vascular processes narrow at right angles to body. Branchial aperture with 6 short lobes, atrial surmounted by a thin, wide lappet.

Picture icon

Text Fig. 2 Distaplia marplesi.
(A) Portion of colony. × 1.
(B) Left side of zooid. × 36.

Pharynx with 16 tentacles of three orders of size regularly arranged, dorsal lamina of three narrow languets. On each side four rows of 18 to 20 stigmata, 4 to 5 times as long as wide, longest in posterior row. Parastigmatic vessels absent. Oesophagus narrow; stomach ovoid with 12 to 16 convoluted folds, contour uneven; intestine wide.

Hermaphrodite zooids. Gonads in posterior end of gut loop. Testis 10 to 14 lobes. Ovary of 1 to 3 eggs level with or slightly anterior to testis.

Distribution: 40–50 fathoms off Oamaru.

Type specimen in Otago Museum.

Note: This species is unlike any described from New Zealand, Australia or the Subantarctic Islands. In mode of growth it is somewhat like D. taylori Brewin, but the shape of the intestinal loop, the form of the stomach, and the number of testis lobes clearly separate it from that species.

Family Styelidae Sluiter, 1895
Genus Berrillia n.gen.

Compound Styelidae with transverse stigmata. Zooids hermaphrodite. Gonads of one sex.

Type of the genus: Berrillia boltenioides.

Note: Up to the present the genus Boltenia of the family Pyuridae has been considered unique among ascidians in the possession of transverse stigmata.

Picture icon

Text Fig. 3—Berrillia boltenioides.
A) Right side of zooid. × 15.
(B) Gut loop. × 30.

– 455 –

Berrillia boltenioides n.sp. (Text Fig. 3 A, B)

Colonies, irregularly-shaped mats up to 16 cm. in length and 3·0 to 9·0 mm. thick. Salmon pink colour of zooids just visible through the sand-encrusted test. Basal membrane not more than 1 mm. thick. Buds arising from bases of zooids. Zooids sub-spherical or pearshaped, tightly packed, up to 3·5 mm. long, 2·0 mm. wide and 5·5 mm. deep (pear-shaped specimens up to 9·0 mm. deep, tapering near substratum to 0·8 mm. in width). Apertures up to 1·3 mm. apart, 0·4 mm. long, 0·4 mm. wide, each with 4 poorly defined lobes. Test 0·1 to 0·2 mm. thick, colourless, covered with fine white sand.

Pharynx with 24 tentacles of 2 orders of size regularly arranged; dorsal tubercle small, rounded, dorsal lamina, a plain, wide, smoothedged membrane; no longitudinal folds, but 4 longitudinal vessels on each side; stigmata, transverse, 20 to 24 rows; no parastigmatic vessels (Text Fig. 3 A).

Oesophagus short; stomach short, tubular, with 12 to 15 small internal longitudinal folds and a curved caecum; intestine wide; anal aperture smooth (Text Fig. 3 B).

A few scattered endocarps.

Gonads on left side only. Three to five ovaries near endostyle, each with numerous ova and a short oviduct opening towards, but far removed from anal aperture. Two to six large testes, often lobed, each with a long, thin sperm duct opening on right in mantle cavity, number of testes seldom corresponding with number of ovaries. As many as 20 salmon pink embryos in various stages of development on right in mantle cavity of specimens collected 22nd October, 1949. Largest tadpole 1·8 mm. long, 0·3 mm. wide in head region.

Distribution: Otago coastal waters (intertidal, on rocks, Victory Beach).

Type in the Otago Museum.

Genus Cnemidocarpa Huntsman, 1913

Cnemidocarpa madagascariensis Hartmeyer var. regalis Michaelsen (Text Fig. 4 A, B)

1916. Cnemidocarpa madagascariensis Hartmeyer, Neue und alte Styelid. Berlin Mus., p. 222, Text Figs. 8, 9.

1922. Cnemidocarpa madagascariensis var. regalis Michaelsen, Vidensk. Mcdd. Naturh. Foren., bd. 73, pp. 430–435.

Body ovoid (Text Fig. 4 A), branchial aperture terminal, atrial removed from it by a little less than a half body length, attachment by posterior end or involving portions of the sides as well, found singly or in twos and threes attached to bivalves or mats of Tubularia. Test wrinkled and buff-coloured posteriorly, warty and tinged with salmon-pink anteriorly, relatively free from incrustations (a few small Bryozoa, etc.), leathery, inner layer pearly white. Siphonal linings cream with eight salmon-pink longitudinal bands. Measurements based on the study of fifteen specimens are: length, 2·2 to 6·5 cm.; breadth, 1·6 to 3·5 cm.; depth, 2·2 to 3·3 cm.; distance between the apertures, 1·0 to 2·5 cm.; branchial siphon, 0·6 to 1·0 cm. long, 0·8 to 1·3 cm. in diameter; atrial siphon, 0·5 to 0·8 cm. long, 0·8 to 1·0 cm. in diameter; thickness of test, 0·5 to 2·0 mm. Mantle

– 456 –
Picture icon

Text Fig. 4—Cnemidocarpa madagascariensis var. regalis.
(A) Individual. × ½.
(B) Dissection showing body opened from the ventral surface, pharynx removed. × 1.

cream with a pink tinge around siphons, musculature strong, longitudinal bundles distinguishable.

Pharynx with 16 to 21 filiform tentacles mostly of one length, but an occasional very small one present; opening of dorsal tubercle U-shaped with ends turned in or out; neural gland small, under nerve ganglion and slightly to left; dorsal lamina plain membrane about two-thirds width of pharyngeal folds; on each side 4 longitudinal folds; longitudinal vessels 141 to 195 on right, 152 to 190 on left, arrangement shown below:

Length of Specimen Arrangement of Vessels on Right Total
6·5 cm. E8(28) 10 (40) 9 (40) 10 (44) 6 195
3·0 cm. E8(21) 8 (36) 8 (34) 6 (33) 6 160

Transverse vessels 4 to 5 small between 2 large. Stigmata straight, 4 to 8 in meshes between longitudinal vessels (average number 5), 5 to 7 times as long as wide, parastigmatic vessels in some areas.

Gut loop (Text Fig. 4 B) occupying ⅓ to ½ of length and entire width of left side. Oesophagus very short; stomach wide cylindrical with 23 to 29 internal longitudinal folds and a pygochord, no caecum; intestine smooth-walled, narrowest in stomach region, to which it is attached by blood vessels; anal aperture 4 or 6 lobed. Endocarps small, usually confined to regions around gut and gonads, 13 to 23 on right, 16 to 43 on left, of which 3 to 8 are in gut loop. Atrial velum a single row of small filiform tentacles.

Gonads of typical Cnemidocarpa type, testis bright yellow, ovary white, gonoducts opening towards the atrial aperture, an occasional gonad bifid. Four to 22 gonads on right (average number 5), 3 to 8 on left (average number 4), confined to lower ⅔ of body. No tadpoles in specimens collected in March, May and September.

Distribution: In New Zealand—var. regalis, Three Kings Island, 65 fathoms (Michaelsen); off Oamaru, 40 to 50 fathoms. Elsewhere—f. typica, South-west Madagascar (Hartmeyer).

Remarks: The specimens described by Michaelsen fall within the range of variability given above, apart from the fact that in his

– 457 –

specimens the pigmentation of the inner lining of the siphon consists of dispersed pigment spots which partly run together to form internal longitudinal bands.

Cnemidocarpa otagoensis n.sp. (Text Fig. 5 A, B, C, D)

Body large, usually elongated in antero-posterior direction, attached by ventral surface to bivalve shells. Test very leathery, wrinkled, white to dirty brown, lightly incrusted by compound ascidians, hydroids, sponges, etc., inner lining pearly white. Siphonal linings with pink edge and four pink internal longitudinal bands. Measurements based on the study of ten specimens are: length, 7 to

Picture icon

Text Fig. 5—Cnemidocarpa otagoensis.
(A) Right side of mantle. × ½.
(B) Left side of mantle. × ½.
(C) Dissection showing body opened from the ventral surface, pharynx removed. × ½.
(D) Transverse section of gonad and mantle wall. × 5.

10·5 cm.; breadth, 3·5 to 5·0 cm.; depth at branchial aperture, 4·5 to 6·5 cm., at atrial aperture, 3·5 to 6·0 cm.; distance between apertures, 4 to 8 cm.; branchial siphon, 1·5 cm. long, 1·5 cm. wide; atrial siphon, 1·5 cm. long, 1·2 wide; thickness of test, 1·5 to 5·0 mm.

Mantle thick, cartilaginous in consistency, colourless except for a horseshoe-shaped band of brilliant orange adipose tissue (Text Figs. 5 A, B, D); strong muscle bundles.

Pharynx with 28 to 38 filiform tentacles of two or three orders of size, irregularly arranged; opening of dorsal tubercle U-shaped with horns turned in or out; neural gland small, elongated, half the length of the nerve cord and to left of it; dorsal lamina a plain, wide membrane, ⅓ width of first pharyngeal fold; on each side 4 internal longitudinal folds; longitudinal vessels 97 to 103 on right side, 95 to 106 on left side, and arranged thus:

– 458 –
Length of Specimen Arrangement of Vessels on Right Total
9·5 cm. E6(16)7(21)6(23)6(17)1D.L. 103
10·5 cm. E7(12)6(20)6(21)6(16)3D.L. 97

Transverse vessels, 7 to 9 small, of which one is of intermediate size between two large. Stigmata 11 to 13 in meshes between folds, 4 to 5 times as long as wide, no parastigmatic vessels.

Gut loop (Text Fig. 5 C) occupying ⅓ to ½ length and entire width of left side, narrow near stomach, open at reflected end. Oesophagus short; stomach not much wider than the rest of the gut, with 12 to 20 folds and a pygochord, no caecum; intestine smooth; anal aperture almost straight-edged, slightly hooded. Endocarps scattered in mantle wall, 12 to 27 on right, 18 to 22 on left, of which 1 to 3 lie in gut loop. Atrial velum single, but occasionally double, row of small filiform or knobbed tentacles.

Gonads large, of typical Cnemidocarpa form. 2 on each side of the body on lower ⅔ on mantle wall. Gonoducts opening towards and near atrial aperture. No tadpoles in specimens collected in March, May, and September.

Distribution: Off Oamaru, 40–50 fathoms.

Type specimen in Otago Museum.

Note: This species is clearly differentiated from other Cnemidocarpa species by the presence of massive adipose reserves in the mantle wall.

Explanation of Lettering
ad.—adipose tissue dl.—dorsal lamina oe.—oesophagus
av.—atrial velum g.—gonad sd.—sperm duct
br.—branchial aperture gc.—gastric caecum st.—stomach
ecp.—endocarp m.—muscle ovary
end.—endostyle testis

References

These are included in those in the previous papers of the series.