A SCENE IN CUBA, WITH CHARACTERISTIC ANIMALS.
A SCENE IN CUBA, WITH CHARACTERISTIC ANIMALS.
In the preceding enumeration the Bahamas have been included with Cuba, as regards the birds they have in common; but they possess some half dozen species not found elsewhere, and even one central American genus of humming-birds (Doricha) not found in any other part of the Antilles. We have thus given Cuba rather more peculiar species than it really possesses, so that the proportionate richness of Jamaica is rather greater than shown by our figures.
The destruction of the forests and the increase of population, with, perhaps, the use of firearms, seem to have led to the extermination of some species of birds in the smaller islands. Professor Newton has called attention to the work of M. Ledru, who, in 1796, described the birds of St. Thomas. He mentions a parrot and a parroquet in the island, the latter only being now known, and very scarce; also a green pigeon and a tody, both now unknown. No less than six species of parrots are said to have been formerly found in Guadeloupe and Martinique, which are now extinct.
Plate XVII. Illustrating the peculiar Mammalia and Birds of the Antilles.—The scene of this illustration is Cuba, the largest of the West Indian islands, and one in which all its peculiar zoological features are well developed. In the foreground is the agouta (Solenodon cubanus), a remarkable insectivorous animal which, with another species inhabiting Hayti, has no allies on the American continent; nor anywhere in the world but in Madagascar, where a group of animals are found constituting the family Centetidæ, to whichSolenodonis said undoubtedly to belong. Above it are a pair of hutias (Capromys fournieri), rat-like animals belonging to the South American family Octodontidæ. They live in the forests, and climb trees readily, eating all kinds of vegetable food. Three species of the genus are known, which are found only in Cuba and Jamaica. Just above these animals is a white-breasted trogon (Prionoteles temnurus), confined to Cuba, and the only species of the genus. Near the top of the picture are a pair of todies (Todus multicolor), singular little insectivorous birds allied to the motmots, but forming a very distinct family which is confined to the islands of theGreater Antilles. They are beautifully-coloured birds,—green above, red and white beneath, and are exceedingly active in their movements. To the right are a pair of small humming-birds (Sporadinus ricordi), not very remarkable in this beautiful family, but introduced here because they belong to a genus which is confined to the Greater Antilles.
Table of distribution of West-Indian Birds.—As the birds of the West Indian islands are particularly interesting and their peculiarities comparatively little known, we give here a table of the genera of land-birds, compiled from all available sources of information. Owing to the numerous independent observations on which it is founded, the discrepancies of nomenclature, and uncertainty in some cases as to the locality of species, it can only be looked upon as an approximative summary of the existing materials on Antillean ornithology.
TABLE OF THE RESIDENT LAND-BIRDS OF THE ANTILLES.
Note.—Genera confined to the West Indies are in Italics. An (a) after (1) indicates a species common to two islands: but where there are two or more species in an island, or the localities are doubtful, this indication cannot be given. All species not otherwise noted are peculiar to the Antilles.
Key to columns:Column 1 Cuba.Col"mn2 Bahamas.Col"mn3 Hayti.Col"mn4 Jamaica.Col"mn5 Portorico & St. Croix.Col"mn6 Lesser Antilles.Col"mn7 Total resident species.
Key to columns:
Column 1 Cuba.
Col"mn2 Bahamas.
Col"mn3 Hayti.
Col"mn4 Jamaica.
Col"mn5 Portorico & St. Croix.
Col"mn6 Lesser Antilles.
Col"mn7 Total resident species.
Vireonidæ.
Tyrannidæ.
Trochilidæ.
Reptiles and Amphibia.—These classes not having been systematically collected, and the numerous described genera not having undergone careful revision, little trustworthy information can be derived from them. The following enumeration of the chief groups hitherto noticed or described, will, however, show very similar features to those presented by the birds—a general relation to Neotropical forms, a more special relation to those of Central America and Mexico, and a considerable number of peculiar types.
Snakes.—Arrhyton(Calamariidæ) from Cuba,Hypsirhynchusfrom Barbadoes,Cryptodacusfrom Cuba,Ialtrisfrom Hayti, andColoragiafrom Cuba (all Colubridæ), have been described as genera peculiar to the Antilles.PhylodryasandDromicus(Colubridæ) are Antillean and Neotropical;Ahætulla, (Dendrophidæ) has the same distribution but extends to tropical Africa;EpicratesandCorallus(Pythonidæ) are Neotropical and Antillean; whileChilabothrusfrom Jamaica andUngaliafrom Cuba and Jamaica (both Pythonidæ) are found elsewhere only in Central America and Mexico. There appear to be no Crotalidæ except an introduced species ofCraspedocephalusin St. Lucia.
Lizards are more numerous.Ameiva(Teidæ) is found all over America,Gerrhonotus(Zonuridæ) is Neotropical and occurs in Cuba;Gymnopthalmusis South American and Antillean. Of Scincidæ seven genera are noted.Celestus(with 9 species) is peculiar to the Antilles;Camilia(1 species) to Jamaica,Panoplus(1 species) andEmbryopus(1 species) to Hayti;Diplogossusis Antillean and South American; whilePlestiodonandMabouyaare cosmopolite. Of Geckotidæ there are four genera;PhyllodactylusandHemidactyluswhich are cosmopolite;Sphærodactyluswhich is wholly American; andCubinafound only in Martinique and Brazil. Of Iguanidæ there are six genera;Anolis, which ranges all over America;Polychrus, which is Neotropical;IguanaandLiocephaluswhich are South American;Tropedurusfound in Cuba and Brazil; andCycluraonly known from Jamaica, Cuba, and Central America.
Amphibia.—The genusTrachycephalus, belonging to theHylidæ or tropical tree-frogs, is almost peculiar to the Antilles; Cuba, Hayti, and Jamaica possessing seven species, while only one is recorded from South America. Other genera are,Peltaphryne(Bufonidæ) from Portorico;Phyllobates(Polypedatidæ) from Cuba;Leiuperus(Ranidæ) from Hayti,—all Neotropical. Of the Urodela, or tailed batrachians, no representative occurs, although they are so characteristic a feature of the Nearctic region.
Fresh-water fish.—The same general remarks apply to these as to the reptiles. Only one peculiar genus is noted—Lebistes, a form of Cyprinodontidæ from Barbadoes; other genera of the same family being,Haplochilus,Rivulus, andGirardinus, widely spread in the Neotropical region; whileGambusiais confined to Central America, Mexico, and the Antilles. Four other families are represented; Siluridæ byChætostomus, found in Portorico and South America; Chromidæ by the South AmericanAcara; Mugillidæ by the Central AmericanAgonostoma; and Percidæ by the North AmericanCentrarchus, of which a species is recorded from Cuba.
Insects.—The various West Indian islands have not been well explored entomologically; one reason no doubt being, that their comparative poverty renders them little attractive to the professional collector, while the abounding riches of Central and South America lie so near at hand. We can, therefore, hardly tell whether the comparative poverty, or even total absence of some families while others seem fairly represented, is a real phenomenon of distribution, or only dependent on imperfect knowledge. Bearing this in mind, we proceed to give a sketch of what is known of the chief groups of Lepidoptera and Coleoptera.
Lepidoptera.—The Neotropical butterfly-fauna is but poorly represented, the majority of the most remarkable types being entirely wanting; yet there are a few peculiar and very characteristic forms which show great isolation, while the majority of the species are peculiar. Four genera are exclusively or characteristically Antillean,—Calistobelonging to the Satyridæ, with four species, of which one ranges to South Carolina;Clothilda(Nymphalidæ) a fine genus which has 4 Antillean species and 2 in Central America;Lucinia(Nymphalidæ) 2 species, confined to Jamaica and Hayti; andKricogoniabelonging to the Pieridæ, which has 2 West Indian species, while 1 inhabits Mexico and Florida. Genera which show a special relation to Central America areEuptoieta,Eumæus, andNathalis. Almost all the other genera are South American, the total number recorded in each family as occurring in the West Indian islands, being, 3 of Danaidæ; 1 of Heliconiidæ; 2 of Satyridæ; 18 of Nymphalidæ; 1 of Erycinidæ; 4 of Lycænidæ; 6 of Pieridæ; 1 of Papilionidæ, and 10 of Hesperidæ. The genusPapiliois represented by about 20 species, 2 of which are North American, 4 South American, while the rest form little characteristic groups allied to those of Central America. The most marked feature seems to be the scarcity of Satyridæ and the almost total absence of Erycinidæ, with a great deficiency in characteristic Neotropical forms of Danaidæ and Nymphalidæ.
Coleoptera.—Cicindelidæ and Carabidæ are very poorly represented, by a few species of wide-spread groups, and hardly any peculiar genera. No Lucanidæ are recorded. Of Cetoniidæ,Gymnetisonly appears to be represented. Buprestidæ seem to be more numerous; 15 genera being recorded, but almost all of wide distribution. One only is peculiar—Tetragonoschoma, found in Hayti;Haleciais the only exclusively South American genus;Chalcophorais widely scattered over the tropical regions but is absent from South America, yet it occurs in the Nearctic region and extends to Jamaica and Guadeloupe. We now come to the Longicorns, the only group of Coleoptera which seems to be well represented, or which has been carefully collected. No less than 40 genera are known from the West Indian islands, and 15 of these are peculiar. Prionidæ are proportionately very numerous, there being 10 genera, 2 of which are widely distributed in both South and North America, 1 is North American, and 1 South American, while the following are peculiar,—Stenodontes(Hayti and Cuba);Dendroblaptus(Cuba);Monodesmus(Cuba and Jamaica);Prosternodes(Cuba);SolenopteraandElateropsis, the two largest genera found in most of theislands. Of Cerambycidæ there are 16 genera, 2 of which range all over America, 4 are Neotropical, 1 South American only, while the following are confined to the islands,—Merostenus,Pentomacrus, andEburiola(Jamaica);Bromiades(Cuba);Trichrous,Heterops, andPæciloderma(Antilles). One genus,Smodicum, is widely spread, having a species in Carolina, 1 in South America, 1 in Hayti, and 1 in West Africa. Of Lamiidæ there are 14 genera, 8 of which are Neotropical, 1 common to Central America and Mexico, 1 to the United States and Cuba, while 2,ProechaandPhidola, are confined to Cuba. Several of the genera are curiously distributed;—Spalacopsisis South American, with 4 species in Cuba and Tropical Africa;Lagocheirusis Neotropical, with a species in Australia; whileLeptostilusis characteristic of the Antilles and North America, with a few species in South America, and one in New Zealand. These cases of erratic distribution, so opposed to the general series of phenomena among which they occur, must be held to be sufficiently explained by the great antiquity of these groups and their former wide distribution. They may be supposed to be the remnants of types, now dying out, which were once, likeCallichroma,Clytus, and many others, almost universally distributed.
All the peculiar Antillean genera of Cerambycidæ and Lamiidæ are allied to Neotropical forms. The peculiar Prionidæ, however, are mostly allied to Mexican and North American groups, and one,Monodesmus, belongs to a group all the other genera of which inhabit the East Indies and South Africa.
Land-shells.—This subject has already been generally treated under the Region, of which, in this class of animals, the Antilles form so important a part. We must therefore now confine ourselves mainly to the internal distribution of the genera, and to a few remarks on the general bearing of the facts.
The excessive and altogether unexampled productiveness of the West Indian islands in land-shells, may be traced to two main sets of causes. The first and least known, consist of the peculiar influences and conditions which render islands always more productive than continents. Whatever these conditionsare, they will be more effective where the islands have been long separated from the mainland, as is here undoubtedly the case. It seems most probable that the great development of land-shells in islands, is due to the absence or deficiency of the vertebrata, which on continents supply a variety of species adapted to prey upon these molluscs. This view is supported by the fact, that in such islands as have been united to a continent at no very distant epoch, and still maintain a continental variety of vertebrata, no such special development of land-shells has taken place. If we compare the Philippine islands with the Sunda group, we find the development of vertebrata and land-molluscs in inverse ratio to each other. The same thing occurs if we compare New Zealand and Tasmania; and we have a still more striking example in the Antillean group itself, continental Trinidad having only 20 genera and 38 species, while the highly insular Jamaica has about 30 genera and more than 500 species.
The other causes favourable to the increase and development of land-shells are of a physical nature. A great extent of limestone-rock is one; and in the larger West Indian islands we have a considerable proportion of the surface consisting of this rock. But perhaps equally or more important, is the character of the land surface, and the texture of the exposed rock itself. A much broken surface, with numerous deep ravines, cutting up the whole country into isolated valleys and ridges, seems very favourable to the specialization of forms in this very sedentary class of animals. Equally favourable is a honeycombed and highly-fissured rock-surface, affording everywhere cracks and crannies for concealment. Now, taking Jamaica as an example of the archipelago, we find all these conditions in a wonderful degree. Over a large part of this island, a yard of level ground can hardly be found; but ridges, precipices, ravines, and rock-bound valleys, succeed each other over the whole country. At least five-sixths of the entire surface is limestone, and under the influence of tropical rains this rock is worn, fissured, and honeycombed, so as to afford ample shelter and concealment for land-shells.
It is probable that the three chief islands, Cuba, Jamaica and Hayti, are nearly equally rich in land-shells; but the last is very much less known, and therefore, perhaps, appears to be much poorer. Cuba has rather more species than Jamaica; but while the former has only 1 peculiar genus (Diplopoma), the latter has 3 (Geomelania,Chittya, andJamaicea), as well as two others only represented in the other islands by single species. From Hayti, only about one-third as many species are known as from the two former islands. It has no peculiar genera, but it has some forms in common with Cuba and others with Jamaica, which show that those islands have more connection with it, than with each other; just as we found to be the case in birds. Portorico and the Virgin islands have still fewer species than Hayti; and, as many of the genera common to the other three islands are wanting, there is, no doubt, here a real deficiency. In the islands farther south (Barbuda to Martinique) more Antillean genera disappear or become very rare, while some continental forms take their place. The islands from St. Lucia to Trinidad have a still more continental character; the genusBulimus, so largely developed on the continent, only reaching St. Lucia. The Bahamas contain about 80 species of land-shells, of which 25 are Antillean, the rest peculiar; all the genera being Antillean. The affinity is chiefly with Hayti and Cuba, but closest with the latter island.
In the West Indian islands as a whole, there are 11 peculiar genera; 9 operculate (Geomelania,Chittya,Jamaicea,Licina,Choanopoma,Ctenopoma,Diplopoma,Stoastoma,Lucidella); and 2 inoperculate (SagdaandStenopus), besidesCyclostomus, which belongs to the Old World and is not found on the American continent. Mr. Bland considers, that many of the Antillean land-shells exhibit decided African and Asiatic, rather than South American affinities. A species of the Asiatic genusDiplommatinahas been found in Trinidad, and an Indian species ofEnneaoccurs in Grenada and St. Thomas; a clear indication that land-shells are liable to be accidentally imported, and to become established in the less productive islands.
Although these islands are so wonderfully rich even now,there is good reason to believe that many species have become extinct since the European occupation of them. When small islands are much cultivated, many of these molluscs which can only live under the shade of forests, are soon extirpated. In St. Croix many species have become extinct at a comparatively recent period, from the burning of forests; and as we know that in all the islands many of the species are excessively local, being often confined to single valleys or ridges, we may be sure that wherever the native forests have disappeared before the hand of man, numbers of land shells have disappeared with them. As some of the smaller islands have been almost denuded of their wood, and in the larger ones extensive tracts have been cleared for sugar cultivation, a very considerable number of species have almost certainly been exterminated.
General Conclusions as to the Past History of the West Indian Islands.—The preceding sketch of the peculiarities of the animal life of these islands, enables us to state, that it represents the remains of an ancient fauna of decided Neotropical type, having on the whole most resemblance to that which now inhabits the Mexican sub-region. The number of peculiar genera in all classes of animals is so great in proportion to those in common with the adjacent mainland, as to lead us to conclude that, subsequent to the original separation from the Mexican area, a very large tract of land existed, calculated to support a rich and varied fauna, and, by the interaction of competing types, give rise to peculiar and specially modified organisms. We have already shown that the outline of the present islands and the depths of the surrounding seas, give indications of the position and extent of this ancient land; which not improbably occupied the space enclosed by uniting Western Cuba with Yucatan, and Jamaica with the Mosquito Coast. This land must have stretched eastward to include Anguilla, and probably northward to include the whole of the Bahamas. At one time it perhaps extended southward so as to unite Hayti with northern Venezuela, while Panama and Costa Pica were sunk beneath the Pacific. At this time the Lesser Antilles had no existence.
The only large island of whose geology we have any detailedaccount, is Jamaica; and taking this as a type of what will probably be found in Cuba and Hayti, we must place the continental period as having occurred after the close of the Miocene, or during some part of the Pliocene epoch, since a large portion of the surface of the former island consists of beds of marine limestone from 2,000 to 3,000 thick, believed to be of Pliocene age. After some time, the land between Hayti and South America subsided, and still later that between Central America and Cuba with Jamaica; but a large tract of land remained insulated, and no doubt supported a very much richer and more varied fauna than now. We have evidence of this in extinct Mammalia of large size, belonging to the peculiar South American family of the chinchillas, which have been found in caves in the small islands of Anguilla, and which, from the character of the land-shells associated with them, are believed to be of Pliocene or Post-pliocene age. This discovery is most interesting, and gives promise of very valuable results from the exploration of the numerous caverns that undoubtedly exist in the abundant limestone strata of the larger islands. This extensive Antillean land, after long continuing undivided, was at length broken up by subsidence into several islands; but as this alone would not account for the almost complete annihilation of the mammalian fauna, it seems probable that the subsidence was continued much farther, so as greatly to reduce the size and increase the number of the islands. This is indicated, by the extensive alluvial plains in Cuba and Hayti, and to a less extent in Jamaica; and by elevated beds of Post-pliocene marls in the latter island.
The series of changes now suggested, will account for all the main features of the Antillean fauna in its relations to that of the American continent. There remains the affinity with Madagascar, indicated bySolenodon, and a few cases of African and Asiatic affinity in insects and land-shells; but these are far too scanty to call for any attempt at special explanation. Such cases of remote affinity and discontinuous distribution, occur in all the regions, and in almost every group of animals; and we look upon them almost all, as cases of survival, under favourableconditions, of once wide-spread groups. If no wild species of the genusEquuswere now to be found, except in South Africa (where they are still most abundant), and in South Temperate America, where their fossil remains show us they did exist not very long ago, what a strong fact it would have appeared for the advocates of continental extensions! Yet it would have been due to no former union of the great southern continents, but to the former extensive range of the family or the genus to which the two isolated remnants belonged. And if such an explanation will apply to the higher vertebrata, it is still more likely to be applicable to similar cases occurring among insects or mollusca, the genera of which we have every reason to believe to be usually much older than those of vertebrates. It is in these classes that examples of widely scattered allied species most frequently occur; and the facility with which they are diffused under favourable conditions, renders any other explanation than that here given altogether superfluous.
TheSolenodonis a member of an order of Mammalia of low type (Insectivora) once very extensive and wide-spread, but which has begun to die out, and which has left a number of curious and isolated forms thinly scattered over three-fourths of the globe. The occurrence, therefore, of an isolated remnant of this order in the Antilles is not in itself remarkable; and the fact that the remainder of the family to which the Antillean species belong has found a refuge in Madagascar, where it has developed into several distinct types, does not afford the least shred of argument on which to found a supposed independent land connection between these two sets of islands.
Summary of the Past History of the Neotropical Region.
We have already discussed this subject, both in our account of extinct animals, and in various parts of the present chapter. It is therefore only necessary here, briefly to review and summarise the conclusions we have arrived at.
The whole character of Neotropical zoology, whether as regards its deficiencies or its specialities, points to a long continuance of isolation from the rest of the world, with a few very distantperiods of union with the northern continent. The latest important separation took place by the submergence of parts of Nicaragua and Honduras, and this separation probably continued throughout much of the Miocene and Pliocene periods; but some time previous to the coming on of the glacial epoch, the union between the two continents took place which has continued to our day. Earlier submergences of the isthmus of Panama probably occurred, isolating Costa Rica and Veragua, which then may have had a greater extension, and have thus been able to develope their rich and peculiar fauna.
The isthmus of Tehuantepec, at the south of Mexico, may, probably, also have been submerged; thus isolating Guatemala and Yucatan, and leading to the specialization of some of the peculiar forms that now characterise those countries and Mexico.
The West Indian Islands have been long isolated and have varied much in extent. Originally, they probably formed part of Central America, and may have been united with Yucatan and Honduras in one extensive tropical land. But their separation from the continent took place at a remote period, and they have since been broken up into numerous islands, which have probably undergone much submergence in recent times. This has led to that poverty of the higher forms of life, combined with the remarkable speciality, which now characterises them; while their fauna still preserves a sufficient resemblance to that of Central America to indicate its origin.
The great continent of South America, as far as we can judge from the remarkable characteristics of its fauna and the vast depths of the oceans east and west of it, has not during Tertiary, and probably not even during Secondary times, been united with any other continent, except through the intervention of North America. During some part of the Secondary epoch it probably received the ancestral forms of its Edentates and Rodents, at a time when these were among the highest types of Mammalia on the globe. It appears to have remained long isolated, and to have already greatly developed these groups of animals, before it received, in early Tertiary times, the ancestors of its marmosets and monkeys, and, perhaps also, some of its peculiar forms ofCarnivora. Later, it received its Camelidæ, peccaries, mastodons, and large Carnivora; and later still, just before the Glacial epoch, its deer, tapir, opossums, antelopes, and horses, the two latter having since become extinct. All this time its surface was undergoing important physical changes. What its earlier condition was we cannot conjecture, but there are clear indications that it has been broken up into at least three large masses, and probably a number of smaller ones; and these have no doubt undergone successive elevations and subsidences, so as at one time to reduce their area and separate them still more widely from each other, and at another period to unite them into continental masses. The richness and varied development of the old fauna of South America, as still existing, proves, however, that the country has always maintained an extensive area; and there is reason to believe that the last great change has been a long continued and steady increase of its surface, resulting in the formation of the vast alluvial plains of the Amazon, Orinoko, and La Plata, and thus greatly favouring the production of that wealth of specific forms, which distinguishes South America above all other parts of our globe.
The southern temperate portion of the continent, has probably had a considerable southward extension in late Tertiary times; and this, as well as the comparatively recent elevation of the Andes, has given rise to some degree of intermixture of two distinct faunas, with that proper to South Temperate America itself. The most important of these, is the considerable Australian element that appears in the insects, and even in the reptiles and fresh-water fishes, of South Temperate America. These may be traced to several causes. Icebergs and icefloes, and even solid fields of ice, may, during the Glacial epoch, have afforded many opportunities for the passage of the more cold-enduring groups; while the greater extension of southern lands and islands during the warm periods—which there is reason to believe prevailed in the southern as well as in the northern regions in Miocene times—would afford facilities for the passage of the reptiles and insects of more temperate zones. That no actual land-connection occurred, is proved by the total absenceof interchange of the mammals or land-birds of the two countries, no less than by the very fragmentary nature of the resemblances that do exist. The northern element consists almost wholly of insects; and is evidently due to the migration of arctic and north temperate forms along the ridges and plateaus of the Andes; and most likely occurred when these organisms were driven southward at successive cold or Glacial periods.
A curious parallel exists between the past history and actual zoological condition of South America and Africa. In both we see a very ancient land-area extending into the South Temperate zone, isolated at a very early period, and developing only a low grade of Mammalian life; chiefly Edentates and Rodents on the one, Lemurs and Insectivora in the other. Later we find an irruption into both of higher forms, including Quadrumana, which soon acquired a large and special development in the tropical portions of each country. Still later we have an irruption into both of northern forms, which spread widely over the two regions, and having become extinct in the land from whence they came, have been long held to be the original denizens of their adopted country. Such are the various forms of antelopes, the giraffe, the elephant, rhinoceros, and lion in Africa; while in America we have deer and peccaries, the tapir, opossums, and the puma.
On the whole, we cannot but consider that the broad outlines of the zoological history of the Neotropical region can be traced with some degree of certainty; but, owing to the absence of information as to the most important of the geological periods—the Miocene and Eocene—we have no clue to the character of its early fauna, or to the land connections with other countries, which may possibly have occurred in early Tertiary times.