Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

Zoology Publications from Victoria University of Wellington—Nos. 33 and 34

[Introduction]

The genus Anguilla Shaw, the sole representative of the Family Anguillidae, has become, with the exhaustive researches of Danish scientists, the most intimately-known genus of eels. The two Atlantic species A. anguilla (L.) and A. rostrata (Le Sueur) were studied thoroughly by Johannes Schmidt over a long period of years, initiating a great deal of further work. His collections formed the basis of a definitive study of the systematics of the genus by Ege (1939), and Jespersen (1942) followed with a detailed account of the leptocephali of many of the Indo-Pacific species of the genus. A considerable amount is nevertheless still to be added, especially concerning the biology of the Southwest Pacific species which, because of limited material, was treated rather briefly by Jespersen.

Ege (1939) has established that there are six Anguilla species present in the Southwest Pacific. Four of these are long-finned species—that is, with the origin of the dorsal fin conspicuously in advance of the level of the anal origin. These page 4
Text-fig. 1.—L. Anguilla megastoma, 26.4mm total length, IFO St 56–4–3 Fig A— Lateral view, to show distribution of major vertical blood-vessels, intestine and myomeres at level of vent. Fig. B—Lateral view of head. Fig. C—Lateral view of caudal region.

Text-fig. 1.—L. Anguilla megastoma, 26.4mm total length, IFO St 56–4–3 Fig A— Lateral view, to show distribution of major vertical blood-vessels, intestine and myomeres at level of vent. Fig. B—Lateral view of head. Fig. C—Lateral view of caudal region.

page 5 are: A. megastoma Kaup with an average of 112 vertebrae and known from the Solomons to Pitcairn; A. marmorata Quoy & Gaimard with about 106 vertebrae and distributed widely throughout the Indo-Pacific from Africa to the Marquesas but not reaching south of New Caledonia or New Guinea in the Southwest Pacific; A. reinhardti Stcindachner with about 108 vertebrae, confined to New Caledonia and eastern Australia from Cape York to Victoria; and A. dieffenbachi Gray with about 113 vertebrae, restricted to New Zealand. The remaining two species are short-finned eels with the dorsal origin only a little in advance of the level of the anal origin. These are: A. australis Richardson with about 112 vertebrae and present in Fiji, New Caledonia, Southeast Australia and possibly Tahiti; and A. obscura Günther with about 104 vertebrae, occurring from Tahiti through Fiji, New Caledonia, North Queensland and New Guinea.

Despite this widespread occurrence of so many species of Anguilla in the South Pacific only four anguillid leptocephali have ever been recorded from this area; these were from the Dana collection (see Jespersen, 1942, pp. 13–15). By contrast, nearly 1500 specimens of Anguilla larvae were taken by the Dana in the whole of the Indo-Pacific. The South Pacific area was widely explored by this vessel during the months of October, 1928, to March, 1929, and Jespersen assumes that the scarcity of Anguilla larvae in this area may have been due to the time of year when the trawling took place. The larvae described here, 12 in number, therefore make a significant addition to knowledge of the South Pacific species of Anguilla. These larvae were collected in similar depths to those of the Dana larvae and in various months of the year, so that Jespersen's assumption is not supported by the present collection.