Page:EB1911 - Volume 03.djvu/999

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BIRD
[CLASSIFICATION


Oscines, and Philepitta of the Clamatores, are remarkable enough to form the types of Passeriform families, and Mesites half-way between Galli and Gruiformes is of prime importance. The Passerine Falculia, with its recently extinguished allies Fregilupus and Necropsar of the Mascarenes; the Coraciine Brachypteracias, Atelornis and Geobiastes, are very abundant, while Heliodilus is an owl belonging to that subfamily which is otherwise represented only by the widely-spread barn owl, Strix flammea. Lastly must be noted the extinct tall Ratite species of Aepyornis with its several fancy genera. But, as Newton charmingly puts it (Dict Birds, p. 353), the avifauna of Madagascar is not entirely composed of such singularities as these. We have homely genera, even among the true Passeres, occurring there—such as Alauda, Acrocephalus, Motacilla and Pratincola, while the Cisticola madagascariensis is only distinguishable from the well-known fan-tailed warbler, C. schoenicola of Europe, Africa and India by its rather darker coloration. But there are also species, though not Passerine, which are absolutely identical with those of Britain, the barn owl, common quail, pigmy rail, and little grebe or dabchick, all of them common and apparently resident in the island. Mauritius had the dodo (q.v.), Lophopsittacus and Aphanapteryx. Rodriguez had the solitaire, Necropsittacus and Necropsar. Bourbon or Réunion had Fregilupus.

Fig. 23.—Extinct Starling of Réunion (Fregilupus varius),
adapted from figures by Daubenton, Levaillant and others.
Reduced.

Some of the Malagasy avifauna is certainly ancient, aboriginal, and even points to India; other forms indicate clearly their African origin; while, lastly, such strikingly characteristic Indo-African birds as hornbills are unaccountably absent.

The Oriental Subregion comprises all the countries and numerous islands between the Palaearctic and Australian areas; it possesses upwards of seventy families, of which, however, only one is peculiar, but this family, the Eurylaemidae or broadbills, is of great importance since it represents all the Subclamatores. Of the many characteristic birds may be mentioned Pycnonotidae or bulbuls, of which the Phyllornithinae are peculiar, Campephagidae or cuckoo shrikes, Dicruridae or drongos, Nectariniidae or sunbirds; pheasants, together with Pavo and Gallus. Some of the similarities to the Ethiopian and the great differences from the Australian avifauna have already been pointed out. Naturally no line whatever can be drawn between the Oriental and the Palaearctic subregions, and many otherwise essentially Indo-Malayan families extend far into the Australian realm, far across Wallace’s line, whilst the reverse takes place to a much more moderate extent. Certainly the Oriental area, in spite of its considerable size, cannot possibly claim the standing of a primary region. It is a continuation of the great Arctogaea into the tropics.

Following H. J. Elwes we subdivide the whole subregion into a Himalo-Chinese, Indian and Malayan province. These divisions had the approval of W. T. Blanford, who proposed the terms Cis- and Trans-gangetic for the two first. The Himalo-Chinese or Trans-gangetic province shows the characteristics of its avifauna also far away to the eastward in Formosa, Hainan and Cochin China, and again in a lesser degree to the southward in the mountains of Malacca and Sumatra. Indo-China is especially rich in Eurylaemidae, China proper and the Himalayas in pheasants.

The Indian or Cisgangetic province is the least rich of the three so far as peculiar genera are concerned.

The Malayan province comprising the Malay islands, besides the Malay peninsula, and the very remarkable Philippines, possess an extraordinary number of peculiar and interesting genera.

The influence of the Australian realm is indicated by a Megapode in Celebes, another in Borneo and Labuan, and a third in the Nicobar islands (which, however, like the Andamans, belong to the Indian province), but there are no cockatoos, these keeping strictly to the other side of Wallace’s line, whence we started on this survey of the world’s avifauna.

D. Classification of Birds

Fürbringer’s great work, published in the year 1888 by the Natura Artis Magistra Society of Amsterdam, enabled Gadow not only to continue for the next five years the same lines of morphological research, but also further to investigate those questions which were still left in abeyance or seemed to require renewed study. The resulting “classification is based on the examination, mostly autoptic, of a far greater number of characters than any that had preceded it; moreover, they were chosen in a different way, discernment being exercised in sifting and weighing them, so as to determine, so far as possible, the relative value of each, according as that value may vary in different groups, and not to produce a mere mechanical ‘key’ after the fashion become of late years so common” (Newton’s Dictionary of Birds, Introduction, p. 103). It is not the quantity but the quality of the anatomical and bionomic characters which determines their taxonomic value, and a few fundamental characters are better indications of the affinities of given groups of birds than a great number of agreements if these can be shown to be cases of isomorphism or heterophyletic, convergent analogy. Nature possesses three great educational or developmental schools—terrestrial, aquatic and aerial life. Each of these affords animal, vegetable or mixed diet. Animal diet implies the greatest variety with regard to locality and the modes of procuring the food. Each of these schools impresses its pupils, in the case of the birds, with its own stamp, but there are many combinations, since in the course of phyletic development many a group of birds has exchanged one school for another. Originally terrestrial groups have taken to an entirely aquatic life, and vice versâ; others, originally endowed with the power of flight, have become, or are transforming themselves into, absolutely cursorial forms; some members of one group live entirely on seeds, while others have become fierce fishers, and so forth. Only by the most careful inquiry into their history can their relationship or pedigree be unravelled. A statement may now be given of Gadow’s classification of birds, in which the extinct forms have been intercalated so far as possible. The few characters assigned to the various groups are sufficiently diagnostic when taken together, although they are not always those upon which the classification has been established:—

Class AVES

I. Sub-class Archaeornithes.—The three fingers and their metacarpals remain separate, each with a claw. Well-developed remiges. Both jaws with alveolar teeth. Amphicoelous. Caudal vertebrae more than thirteen, without a pygostyle, but with about twelve pairs of rectrices. Archaeopteryx, A. lithographica, s. macroura, two specimens from the upper Oolite of Solenhofen, Bavaria.

II. Sub-class Neornithes.—Metacarpals fused. Second finger the longest. Not more than thirteen caudal vertebrae.

I. Division Ratitae.—Terrestrial, flightless. Without sternal keel. Quadrate bone with single proximal knob. Without pygostyle. Coracoid and scapula fused. Compound rhamphotheca. Adult without apteria. With copulatory organ. A collective polyphyletic or heterogeneous group, originally cosmopolitan; with certainty existing since the Miocene.
1. Order Struthiones.—With pubic symphysis. Two toes only, third and fourth. Struthio, ostrich, Pliocene of Samos and of north-west India, now Africa and Arabia.
2. Order Rheae.—With long ischiadic symphysis. Three toes. Mesembriornis, Miocene or Pliocene of Argentina. Rhea, South America.