Art. XXIV.—Notice of an Electric Ray new to the Fauna of New Zealand, belonging to the Genus Astrape.
[Read before the Otago Institute, 12th November, 1901.]
During the cruise of the “Doto” in the southern coastal waters of New Zealand, in the early part of 1900, a specimen was caught in Foveaux Strait, in the seventy-sixth haul, in shallow water, of a cramp-fish or torpedo ray, which appears to be an addition to the list of our New Zealand fishes. I
received the specimen from Mr. Ayson, who was in charge of the experimental trawling, on his return to Dunedin. The fish had been placed with other specimens in a jar of strong alcohol, and presented a very shrivelled appearance, the skin being very loose and full of creases and folds. The shape of the body, excluding the short tail, was nearly circular, being 8 in. in each diameter (Plate X.). The total length of the body, including the tail portion, was 10 ¾ in.
In November of the same year I obtained a fresh specimen of this curious fish from a fish-shop in Dunedin, which had been caught the previous night by the steam-trawler some distance outside of the Otago Heads. The general shape and appearance of this specimen was so unlike the other that I thought they must be different species, but on examination I find no material points of difference, except in the general outline, as shown in the plate. The outline figures there given are mechanically reduced from outlines made by passing a pencil round the edges of the fish while it rested on a piece of paper. I am therefore compelled to think that the first specimen must have been much altered in shape by the action of the spirit.
The proper shape of this interesting fish appears to be more of a long oval than a circle, the measurements being 7 in. in greatest diameter and 14½ in. in length.
The very minute, almost invisible, eyes, the single dorsal, and the position of the vent, place it in the genus Astrape of Muller and Henle. In the absence of further specimens (both those obtained being males), and not having the necessary literature, I cannot say that it is absolutely the same as Astrape capensis. I have therefore, as already intimated in my report of the 5th July, 1900, called the New Zealand specimens Astrape aysoni, after their first discoverer.
The British Museum catalogue records Astrape capensis from the Cape and from the coast of Madagascar, and an allied species is recorded from Japan, but I cannot get any description for comparison with the New Zealand specimen, nor any illustrations.
Genus Astrape, Mull, and Henle.
Astrape, Mull, and H.
Tail with a fold on each side. Body entirely naked; upper surface reddish-brown, lower surface white and yellowish-white. One dorsal fin only on the tail, without spine. Caudal well developed. Anterior nasal valves confluent into a broad flap overhanging the mouth. Teeth pointed; dental laminæ scarcely extending beyond the other margin
of the jaws. Spiracles immediately behind the eyes, which are very minute, and hardly traceable under the skin. An electric apparatus between the head and pectoral fins.
Explanation of Plates X.—XII.
Astrape aysoni, n. sp.
Astrape aysoni, head.
Astrape aysoni, under-surface: fig. a from live specimen; fig. b from spirit specimen; fig. c, tail.