Southern Temperate Zone
genera south tropical northern
SOUTHERN TEMPERATE ZONE. - This zone includes the coasts of the southern extremity of Africa from about 30° S lat., of the south of Australia, with Tasmania, and of New Zealand, and the Pacific and Atlantic coasts of South America between 30° and 50° S lat.
The most striking character of this fauna is the reappearance of types inhabiting the corresponding latitudes of the northern hemisphere, and not found in the intervening tropical zone. This interruption of the continuity in the geographical distribution of shore fishes is exemplified by species as well as genera, for instance - Chintoera monstrosa, Galeus canis, Acanthias vulgaris, "leant/has blainrillii, Mina squatina, Zeus faber, Lophius piscatorius, Centriscus scolopax, Engraulis encrasicholus, Clupea sprattus, Conger vulgaris. Instances of genera are still more numerous : - Cestracion, Spittax, Pristiophorus, React; Callanthias, Polyprion, Histiopterus, Canthar us, Box, Girella, Pagel Ins, Chilodactylus, Sebastes, Aploactis, Agonus, Lepidopus, C !Nutt, Psychroluthice, Notacanthus ; Lycodes, Merlucchts, Lotella, Phycis, Motella ; Aulopus ; Urocampus; Solenognathus , Myxine.
Naturally, where the coasts of the tropical zone are continuous with those of the temperate, a number of tropical genera enter the latter, and genera which we have found between the tropics, as well as in the temperate zone of the northern hemisphere, extend in a similar manner towards the south. But the truly tropical forms are absent ; there are no Sgitainip-innes, scarcely any Mullicice, no Acronuri, no Teuthyes, no Pontacentridce (with a single exception on the coast of Chili), only one genus of Julidina, no Scarina, which are replaced by another group of Pharynglgnaths, the Wachtel. The Labrina, so characteristic of the temperate zone of the northern hemisphere, reappear in a distinct genus (Jfalacopterus) on the coast of Juan Fernandez.
The family of Berychk, equally interesting with regard (Trachichthys) is much more nearly allied to the northern than to the tropical genera.
The true Cottina and Heterolepidina (forms with a bony stay of the preeoperculum, which is generally armed) have not crossed the tropical zone ; they are replaced by fishes extremely similar in general form, and having the same habits, but lacking that osteological peculiarity. Their southern analogues belong chiefly to the family Trachinidce, and are types of genera peculiar to the southern hemisphere.
The Dtscoboli of the northern hemisphere likewise have not penetrated to the south, where they are represented by Uobiesocidoe. These two fainilies replace each other in their distribution over the globe.
Nearly all the Pletironectidce (but they are not numerous) belong to distinct genera, some, however, being remarkably similar in general form to the northern Pleuronectes.
With Gadoids Myxinidce reappear, one species being extremely similar to the European Myxine. Bdellostoma is a genus peculiar to the southern temperate zone.
As in the northern temperate zone, so in the southern the number of individuals and the variety of forms is much less than between the tropics. This is especially apparent on comparing the numbers of species constituting a genus. In this zone genera composed of more than ten species are the exception, the majority having only from one to five.
The proportion of genera limited to this zone is very high, about 65 out of a total number of 170 being peculiar-to it.
The Cape of Good Hope district. Many of the genera found in this district are northern forms (Chimera, Galeus, Seylliune, Acanthias, Torpedo, Rain, Dotter, Cantharus, Box, Sagrus, Pagrus, Pagellus, Chrysophrys ; &bastes, Sphyrcena Lepidopus, Thyrsites ; Zeus ; Lophius ; Motena), which in conjunction with the peculiarly southern types (Callorhynchus, Chilodactylics, Agriopus, Clinus, Gengpterus, Bdellostoma) leave no doubt that this district belongs to the southern temperate zone, whilst the freshwater fishes of South Africa art' members of the tropical fauna. Only a few (Rhinobatus, Nareine, Astrope, and Sphyrcena) have entered from the neighbouring tropical coasts. The development of Sparoids is greater than in any of the other districts of this zone, and may be regarded as one of its distinguishing features.
The South Australian district comprises the southern coasts of Australia (northwards to about the latitude of Sydney), Tasmania, end New Zealand. It is the richest in the southern temperate zone, partly in consequence of a considerable influx of tropical forms on the eastern coast of Australia, where they penetrate farther southwards than would be expected from merely geographical considerations, partly in consequence of the thorough manner in which the ichthyology of New South Wales and New Zealand has been explored. Of the 120 genera hitherto found in this district 42 are peculiar.
The shore fishesof New Zealand are not so distinct from those of south-eastern Australia as to deserve to be placed in a separate district. With the exception of the genera which enter this zone from the tropics, and which are more numerous on the Australian coast than on that of New Zealand,. and a few very local genera in addition, the remainder are identical. Many of the South Australian species, too, are found also on the coasts of New Zealand. The principal points of difference are the extraordinary development of Mon-acanthus on the coast of South Australia, and the apparently total absence in Australia of Gadoids, which in the New Zealand fauna are represented by 6 genera.
other districts of this zone. Three are peculiar, viz., Mendosorna„ ifyxodos, and .illalacopterus ; Porichthys and Agonus have penetrated thus far southwards from the Peruvian and Californian districts ; and Pulyprion, is one of those extraordinary instances in which a very specialized form occurs at almost opposite points of the globe, without having left a trace of its previous existence in, or of its passage through, the intermediate space.