Brooding or Nurse Anemone (Sea Anemones of New Zealand)

Brooding or Nurse Anemone

Cricophorus nutrix

Description ⁴

Common small anemone found on kelp.
Habitat
Brown kelp, often in cup shaped hollows between stalk and branches.

Column
Smooth, often deep brown but varies from yellow through olive. Often visually striped from top to bottom. A wrinkle around the column, about a third of the way up, acts as a brood pouch.
10 to 20mm high.

Oral disc
Iridescent, orange or green fading towards the outside, 10 to 15mm diameter. Mouth light blue or bright pink to magenta with an orange throat.

Tentacles
Light brown tinged with green, up to 96, 2 to 5mm long, tentacles in 4 whorls. Outer whorls maybe white, blue/green or pale blue with brown tips.

Distribution
Endemic, throughout NZ.

An edited version of Transactions and Proceedings of the Royal Society of New Zealand 1868-1961, Art. XXXVI, Volume 41, 1908, pp374-398.
A Review of the New Zealand Actiniaria known to Science, together with a Description of Twelve New Species.
By F. G. A. Stuckey, M.A.

This is the brown sagartian mentioned by Farquhar as probably forming the food of the butter-fish. It is found only on Lessonia, where it establishes itself in colonies.

Column.—The colour is, in general, deep brown, but there is some variation. Some specimens were greenish, some blue, and some yellow. The whole animal is iridescent. No cinclides are present.

Tentacles.—These are short and fine, and placed at the edge of the disc in three or four crowded cycles.

Oral Disc.—The colour is generally iridescent green, but it is very variable. The mouth is pink or magenta, and there are radial markings. The structure of the disc resembles that of the tentacles, but the musculature is weaker.

Presumably the young of this species are retained in the body till fully formed, for I found one specimen which had twelve young ones attached to the outside of the body-wall in a regular transverse circle about one-third of the height of the wall from the foot. If the young are not retained till they are considerably advanced, it is difficult to see how they can become attached in this manner unless there are external brood - pouches. I have seen no evidence in support of the latter view.

Acontia.—These are emitted from the mouth readily, but not in great numbers.

Dimensions.—Height, 12 mm.; breadth, about the same.

An edited version of Papers from Dr. Th. Mortensen's Pacific Expedition 1914-16. XXI.
Actiniaria from New Zealand and its Subantarctic Islands.
By Oskar Carlgren, Lund.

Tentacles to 96 (6+6+12+24+48), the inner more than twice as long as the outer. Embryos developing in an annular invagination around the column in its proximal half.

Colour. Column in general deep brown, sometimes greenish blue or yellow. Oral disc iridescent green, but the colour is very variable. Mouth pink or magenta with radial markings. The whole animal is iridescent (Stuckey).

Dimensions. Height and breadth l.2 cm in extended state? (Stuckey). In preserved state: 1) Height 1, breadth 0.9 cm. 2) Height 0.7, breadth 0.6 cm.

Exterior aspect. The wide pedal disc. The column is cylindrical to conical, smooth without cinclides, in certain stadia of contraction somewhat longitudinally folded. In many specimens there is a circular wall in the proximal half. The margin is distinct. The tentacles are short, fine and smooth, placed at the margin and hexamerously arranged 6 + 6 + 12 + 24 + 48 = 96, in large specimens the inner are more than twice as long as the outer. The greater part of the oral disc is devoid of tentacles. It is provided with radial furrows. The mouth is situated on a conus. The actinopharynx is well developed with longitudinal folds and provided with two rather distinct siphonoglyphes.

Anatomical description. This species is very interesting as provided with a circular brood-pouch in such a simple form as not before observed in Actilliaria). Stuckey writes: "Presumably the young of this species are retained in the body till fully formed for I found one specimen, which had twelve young ones attached to the outside of the body-wall in a regular transverse circle about one third of the height of the wall from the foot. If the young are not retained till they are considerably advanced it is difficult to see how they can become attached in this manner unless there are external brood pouches. I have seen no evidence in support of the latter view."
As we see from the description above, Stuckey has only observed one specimen the young of which had already left their brood-pouch. In fact this species has formed only a single brood-pouch consisting of a circular invagination around the column in its lower half. Already in younger individuals there are sometimes a distinct circular wall in the above named place. A longitudinal section of the column wall in this place shows that we have to do with a circular, though as yet rather shallow, invagination. The invagination contains no embryos. In a more advanced state the circular brood-pouch is considerably enlarged and reaches below the actinopharynx. In the sectioned specimen the brood-pouch contained several embryos not having developed their tentacles. As long as the embryos are small, both rims of the brood-pouch are closely pressed together, when the embryos grow they emigrate from the brood-pouch and attach themselves in the expanded outer part of the brood-pouch. In this stadium the embryos seem to stand in a circular furrow around the animal. From here they emigrate to the column wall.

It is this species which is mentioned by Dr. Mortensen in his paper "Observations on protective adaptions and habits, mainly in marine animals" as an instance of protective resemblance in an Actinian. It is stated to resemble the peculiar branches of the alga, on which it lives, to such a degree that it was very hard to distinguish.

References ⁴

Note any thumbnails in this section are only to indicate what that reference shows while this page is being built. They have not yet been verified, don't assume they are correct examples.

Synonyms:

Sagartia nutrix

Sources and Credits

(c) Tony Wills, some rights reserved (CC BY-SA), uploaded by Tony Wills
(c) Lisa Bennett, some rights reserved (CC BY), uploaded by Lisa Bennett
Tony Wills, no known copyright restrictions (public domain), uploaded by Tony Wills
(c) Tony Wills, some rights reserved (CC BY-SA)

More Info

iNaturalist NZ Map

‹ › ×