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Section IX.—The Maori An Sub-region
The Maorian Sub-region includes, besides New Zealand proper, many smaller groups of islands in the sea around, such as Norfolk Island, the Kermadec group, Chatham Island, Stewart Island, Auckland Island, Campbell Island, and Macquarie Island, and probably Lord Howe's Island, though in some respects this appears to belong rather to the Australian mainland than to New Zealand.
As in the Polynesian Sub-region, there are no indigenous terrestrial mammals found in this Sub-region, the only exception being a species of rat (Mus maorium). But it is quite possible, nay, probable, that this Rat, as its name seems to imply, was brought by the invading Maoris into New Zealand from Tonga, or from wherever the Maoris originated; indeed, Mr. Thomas believes it to be identical with a Polynesian species, Mus exulans (cf. Buller, Trans. N. Z. Inst, xxv. p. 49). The only two bats recorded from New Zealand are Mystacina tuberculoid, the genus as well as the species being restricted to New Zealand; and Chalinobus morio, which is also found in Australia. .
The islands of New Zealand are indeed remarkable as being the only insular area on the globe, of any considerable size, which are entirely destitute of mammal-life. All the other large islands of the world possess a Mammalfauna of greater or less extent related to the continent to which they are nearest, and have consequently been termed by Mr. Wallace "continental islands." All such "continental islands" are separated by narrow seas, of no great depth, from their respective continents. New Zealand alone, of all the larger islands of the globe, is disconnected by a considerable breadth of ocean (about 1400 miles) and also by a deep sea (more than 2000 fathoms) from the nearest point of mainland.
This fact and the absence of an indigenous Mammalfauna show that New Zealand has not been joined directly by land with Australia recently, even in a geological sense of that term; possibly it has never been so connected at all.
To determine, therefore, the geographical affinities of this Sub-region, we must turn to the birds and to the other lower groups, and so endeavour to gain an idea of the affinities of these interesting islands. In New Zealand the want of mammals has been apparently supplied in former epochs by the great development of two families of flightless birds. One of these groups, the Kiwis (Apterygidm), is still represented by five or six species, although these birds are being rapidly exterminated by the British colonists. The other group, the Moas (DinornithicUe), is now quite extinct, but as remains of their skin and feathers have been found in some of the caves of the Southern Islands, and as the ancient legends and songs of the Maoris contain unmistakable references to them, it is probable that they have ceased to exist only within the last few hundred years.
In addition to the flightless birds, recent and extinct, New Zealand still possesses two very singular forms of Parrots (Nestor and Stringops), for the reception of which special families have been formed; and eighteen other peculiar genera of land-birds, most of which are related more or less remotely with Australian forms. Altogether there are in New Zealand fifty-seven land-birds, belonging to thirtyfour genera, of which sixteen, or nearly half, are not known elsewhere. There are also five peculiar genera of waders and aquatic birds in New Zealand, making twenty-one indigenous genera in all. Among its few reptiles, also, New Zealand numbers the very remarkable Tuatera (Sphenodon punctaius), which, though externally resembling a lizard, differs from all other lacertians in so many points of its skeleton and internal structure that it is usually considered to belong to a separate and distinct order of reptiles. The nearest allies of this form are found among three extinct families which make up the order Rhynchocephalia. Remains of these families occur in beds of Permian age in Germany, in the Keuper of Elgin (Scotland), and in the (probably contemporaneous) Gondwana beds of India, as likewise in the lower Eocenes of North America and Northern Europe.
All these facts indicate a great amount of individualism in the Maorian Sub-region. But on the whole they betray an affinity to the tropical parts of Australia and to the Papuan Sub-region rather than to the temperate portion of Australia, to which New Zealand is now nearest in point of actual distance. This connection is further confirmed by the soundings of the seas round the islands, which show that, although on the west, south, and east deep water extends all round, a long submerged bank, with a depth of less than 1000 fathoms, stretches along to the north-west, and connects the shallow waters round Australia with those round New Zealand.
It is probable that the land connection between the two areas, if it ever actually existed, took place somewhere along this line.
As already mentioned in the first chapter of this volume, some writers on Geographical Distribution, especially Professor Huxley and Professor Newton, are inclined to give to New Zealand and its islands the rank of an independent Region among the primary divisions of the globe. There is, no doubt, as has just been shown, a good deal to be said for this proposal; but, on the other hand, there are even stronger reasons for retaining New Zealand as a Sub-region of the Australian Region. In the first place, we are here dealing with Mammals alone, and it seems rather absurd to assign the value of a primary Region to a group of small islands characterised by the almost entire absence of that class of animals with which we are most concerned. In the second place, looking at Regions from a more general point of view, there is a great practical convenience (as Mr. Wallace has pointed out) in keeping the more or less equal divisions of the globe as primary divisions. It seems, therefore, to be quite unnecessary to elevate so small a portion of the world into a Primary Region. Other small insular areas might, with some justice, put forward nearly similar claims. In the third place, although New Zealand possesses no indigenous terrestrial Mammals, yet the fauna, such as it is, shows an unmistakable affinity of various degrees to that of Australia, and more especially to the tropical part of that continent. It is, indeed, probable that the whole of the fauna of New Zealand has been originally derived from that source, although in the greater number of cases it has undergone considerable modification.
Dr. H. 0. Forbes (4) has lately published a speculative article on the former existence of a (now mostly submerged) southern continent, the remains of which are represented by the land round the South Pole, while former arms stretched upwards and embraced New Zealand, Eastern Australia, Tasmania, Madagascar, the Mascarene Islands, and part of South America. The grounds for this bold assumption, which, although by no means new, has not been previously developed to so great an extent, rest chiefly on the finding of the remains of a large ocydromine rail in the Chatham Islands, allied to the now extinct Aphanapteryx of Mauritius, and the fossil bones of a large coot (Fvlica) allied to F. newtoni of the same island. Other evidence adduced is that of the occurrence of the Batitm, or Struthious birds, in New Zealand, Australia, Madagascar, and Patagonia. But the distribution of Struthious birds is probably to be explained much in the same way as the distribution of other archaic forms, such as the lemurs and tapirs. They are remnants of what were formerly widely spread groups. That this is likely to be the case is shown by the recent discovery, in other parts of the world (such as the Sewaliks of India, and the Eocenes of England and France) of the remains of other extinct Ratite birds.
Another piece of evidence brought forward by Dr. Forbes is the occurrence of Didunculus in the Sarnoan group, and of the Dodo (Didus), to which Diduncvlus was once supposed to be nearly related, in Mauritius. But it is now allowed that Didvmculus has little near affinity to the Dodo, and that it is in fact a mere strongly modified member of the family Columbidae.
Mauritius, as a matter of fact, is in every way a typical oceanic island, and there seems to be little evidence, either physical or zoological, of its having been ever connected with any other land.