In some cases, such as the Ethiopian and Neotropical and the Palaearctic and Nearctic regions, the faunas, although distinct, are related, several forms on opposite sides of the Atlantic being analogous, e.g.
Sclater' was the first to divide the world into a few great " regions," the Palaearctic, Ethiopian, Indian and Australian forming one group, the " Old World " (Palaeogaea); and the Nearctic and Neotropical forming a second, the New World (Neogaea).
They express the main complexes of land with their dependencies in well-chosen terms; for instance the " Neotropical region " stands short for South and Central America with the Antilles.
Neotropical Region Columbian Patagonian III.
(B) Neogaea, or the Neotropical region.
- Excepting towards the north, where, in Mexico, it meets, and inosculates with the Nearctic subregion, the boundaries of the Neotropical region are simple enough to trace, comprehending as it does the whole of South America and all Central America; besides including the Falkland islands to the south-east and the Galapagos under the equator to the west, as well as the Antilles or West India islands up to the Florida channel.
The Tyrannidae, has evidently been led by the geographical continuity of its soil with that of the Neotropical region, such forms do not occur elsewhere.
The differences between the Neotropical avifauna and that of North America are fundamental and prove the independence or superior value of the Neotropical region as one of the principal realms.
There is no family of birds common to the Nearctic area and the Antillean subregion without occurring also in other parts of the Neotropical region, a fact which proves its, affinity to the latter.
The close affinity of North America with the Palaearctic avifauna becomes at once apparent if we exclude those groups of birds which we have good reason to believe have their original home in the Neotropical region, notably numerous Tyrannidae, humming-birds and the turkey-buzzards.
The following groups may be mentioned as characteristic and typically American, and, since we consider them as comparatively recent immigrants into the Neotropical region, as originally peculiar to the Nearctic area: Mniotiltidae, Vireonidae, Icteridae, Meleagris and various Tetraoninae.
To compare the Palaearctic genera with those of the Australian and Neotropical regions would be simply a waste of time, for the points of resemblance are extremely few, and such as they are they lead to nothing.
Struthio in Africa and Arabia, fossil also in the Sivalik Hills, and Aepyornithidae in Madagascar; Pittzdae, Bucerotinae and Upupinae, of which Upupa itself in India, Madagascar and Africa; Coraciidae; Pycnonotidae or bulbuls; Trogonidae, of which the Asiatic genera are the less specialized in opposition to the Neotropical forms; Vulturidae; Leptoptilus, Anastomus and Ciconia among the storks; Pteroclidae; Treroninae among pigeons.
Ardeidae, cosmopolitan; including Cancroma, Neotropical, Balaeniceps, Scopidae, Ethiopian.
Momotidae, neotropical, motmots and todies.
Neotropical and distinctively Sonoran insects mingle with members of the Holoarctic fauna across a wide " transition zone " in North America.
Interesting relationships between the Ethiopian and Oriental, the Neotropical and West African, the Patagonian and New Zealand faunas suggest great changes in the distribution of land and water, and throw doubt on the doctrine of the permanence of continental areas and oceanic basins.
Relationship of this otherwise typically carinate, neotropical family with the Ratitae had already been insisted upon by T.
The manakins are peculiar to the Neotropical Region and have many of the habits of the titmouse family (Paridae), living in deep forests, associating in small bands, and keeping continually in motion, but feeding almost wholly on the large soft berries of the different kinds of Melastoma.
Liocerus, neotropical) may be taken as examples of long and slender tree-snakes.
About 30 species, with several genera, are known from the oriental and neotropical regions.
The family ranges all through the neotropical region, inclusive of the Galapagos and the Antilles, into the southern and western states of North America.
To this species are more or less closely allied numerous birds inhabiting the Palaearctic and Indian regions, as well as the greater part of America, but not occurring in the Antilles, in the southern portion of the Neotropical Region, or in the Ethiopian or Australian.
They are peculiar to the neotropical region - a few species finding their way into southern Mexico and none beyond.
In outward appearance the motmots have an undoubted resemblance to bee-eaters, but, though beautiful birds, various shades of blue and green predominating in their plumage, they do not exhibit such decided and brilliant colours; and, while the beeeaters are only found in the Old World, the motmots are a purely Neotropical form, extending from southern Mexico to Paraguay, and the majority of species inhabit Central America.
With three exceptions, all the genera of this extensive family belong to the New World, being specially characteristic of the Neotropical region, where they occur as far south as Patagonia, while extending northward into the warmer parts of the Nearctic regions as far as California and British Columbia.
In all the species except the African species there is a globular receptaculum seminis opening by two short ducts close together into the oviduct, and in the neotropical species there is in addition a small receptaculum ovorum, with extremely thin walls, opening into the oviduct by a short duct just in front of the receptaculum seminis.
In the neotropical species the egg is minute, and almost entirely devoid of yolk.
Specimens were subsequently obtained from other parts of the neotropical region, and from South Africa and Australia, and the animal was variously assigned by the zoologists of the day to the Annelida and Myriapoda.
(The following genera have been proposed: Peripatus for the neotropical species, Peripatoides for the Australasian, Peripatopsis and Opisthopatus for the African, Paraperipatus for the New Britain, Eoperipatus for the Malayan species, and Ooperipatus for the supposed oviparous species of Australia and New Zealand.) The colour is highly variable in species from all regions; it is perhaps more constant in the species from the neotropical region than in those from elsewhere.
The following species are aberrant in respect of these characters: Peripatus (Opisthopatus) cinctipes, Purcell (Cape Colony and Natal), presents a few Australasian features; there is a small receptaculum seminis on each oviduct, some of the legs are provided with welldeveloped coxal organs, the feet have one anterior, one posterior and one dorsal papilla, and the successive difference in the ages of the embryos in the uterus, though nothing like that found in the neotropical species, is slightly greater than that found in other investigated African species.
P. tholloni, Bouvier, (Equatorial West Africa [Gaboon]), shows some neotropical features; there are 24 to 25 pairs of legs, the genital opening is between the penultimate legs, and though there are only three spinous pads the nephridial openings of the 4th and 5th legs are proximal to the 3rd pad, coxal organs are present, and the jaws are of the neotropical type; the oviducts have receptacula seminis.
The neotropical species appear to fall into two groups: (I) the so-called Andean species, viz.
The remaining neotropical species, in which there are 3 papillae on the foot and the nephridial openings of the 4th and 5th legs are between the 3rd and 4th pads.
The primary papillae of the neotropical character with conical bases.
It will thus be seen that the Malay species, while resembling the neotropical species in the generative organs, differ from these in many features of the legs and feet, in the important characters furnished by the site and structure of the ovum, and by their early development.
We should have four great realms:-(1) Europe and Northern and Temperate Asia, Africa north of the Sahara (palaearctic region) and North and Central America (nearctic region); (2) Africa and South-Eastern Asia (Ethiopian and Indian region); (3) South America (neotropical region); and (4) Australia (Australian region).
The first would be characterized by the Caudata, which are almost confined to it (although a few species penetrate into the Indian and neotropical regions), the Discoglossidae, mostly Europaeo-Asiatic, but one genus in California, and the numerous Pelobatidae; the second by the presence of Apoda, the prevalence of firmisternal Ecaudata and the absence of Hylidae; the third by the presence of Apoda, the prevalence of arciferous Ecaudata and the scarcity of Ranidae, the fourth by the prevalence of arciferous Ecaudata and the absence of Ranidae, as well as b y the absence of either Caudata or Apoda.