Recent submarine, geological, and geophysical investigations including diving surveys reveal the geo-history of the Ryukyu Islands and the East China Sea. Two stages are fundamental for formation processes of the Ryukyu Arc. The crustal thinning in the western part of the East China Sea and thus eastward drifting of the Arc may have occurred in the late Miocene to middle Pliocene at the first stage. Between 1.6 - 1.3 Ma, the East China Sea area, including most of the Okinawa Trough, may have been subaerial. At that time, the Ryukyu Arc region may have been a part of the Eurasian continent. Extensive subsidence may have occurred at the second stage, at about 1.3 Ma, in the early Pleistocene. The present Ryukyu Arc (Ryukyu Ridge) has been formed since then. The Ryukyu Arc may have been nearly connected to the Chinese continent, through Taiwan as a land bridge, sometime during the two major development periods (such as sometime during 1.6 - 1.0 Ma, and 0.2 - 0.025 Ma). The paleo-land may have been submerged step by step since 0.03 Ma by both crustal movement and sea-level rising after the last Ice Age. Submarine stalactite caves at 10 - 35 m deep off the Ryukyu Islands were discovered. The caves have subsided since the Wiirm Ice Age. Stone tools were also recovered inside one of them. Additionally, archeological evidence in the form of a stepped pyramid, estimated at greater than 6,000 years old, has been discovered beneath the sea off Yonaguni Island. Existence of such submarine ruins provide indicators of subsidence processes of the Ryukyu Arc.

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Results of present studies on the stratigraphic levels and the paleontological analysis of terrestrial vertebrate fossils in the Ryukyu islands furnish valuable clues and considerations as to the history and age of animal migration from the continent to its neighboring islands. To date, four diagnostically different stratigraphic levels containing Late Miocene to latest Pleistocene vertebrate fossils have been delineated in the islands. Geological and paleontological data suggest that the area of the Ryukyu Islands has been repeatedly connected to the Asiatic Continent and each land connection has been followed by migration of characteristic terrestrial vertebrates from the continent.
Among the fossil assemblages found in these four different stratigraphic levels, those from Level 2 (Early Pleistocene) are known to occur in shallow marine deposits underlying the Early to Middle Pleistocene Ryukyu Group. They are considered to be immigrants from either the latest Pliocene Renzidong fauna (Jin & Zheng, 1998; Huang, 1998; Jin et al., 1999) in Anhui Province or the Wushan hominid fauna (Huang et al., 1991) in Sichuan Province, both located in Central China, during the second land connection. This assemblage may be regarded as the oldest post-Miocene fauna and might include the ancestors of the Pleistocene fossil and living endemic terrestrial vertebrate faunas of the Ryukyu islands.
Another important species of fossil assemblage of terrestrial vertebrates in the islands is closely associated with the latest Pleistocene fissure and cave deposits developed within the Ryukyu Group or coeval terrace deposits (Level 4). These assemblages are considered to be mixed faunas that migrated from the Asian mainland to the islands during different periods of land connection in the past. Terrestrial vertebrate fossils from this level include large mammal (deer) and giant tortoise that became extinct at the end of the latest Pleistocene. However, descendants of other animals including mammals, amphibians and reptiles, are still living in the islands forming characteristic insular endemic fauna.

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Throughout the Ryukyu Islands, many Pleistocene terrestrial vertebrate remains occur from the fissure and cave deposits which were formed in the early to late Pleistocene Riukiu Limestone. The remains are found from about one hundred localities and are composed of 51 species of 39 genera.
This report deals with Minatogawa Fissure in case of fissure deposits and Jibu-do Cave, Futenma-gu Cave, Shimoji-baru Cave, and Pinza-abu Cave in case of cave deposits, in Okinawa Prefecture. In addition to the remains from these localities, those from other three localities such as Teruma, Sonan, and Imadomari are discussed from the paleontological and geologic viewpoint. Also the migration to the Ryukyus of the fossil animals is discussed.

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The Ryukyu Archipelago accommodates 52 native species/subspecies (26 genera belonging to ten families) of terrestrial reptiles and 22 native species/subspecies (ten genera belonging to six families) of amphibians. This paper reviews the geographic similarity and diversity patterns of the current herpetofauna of the Ryukyus and adjacent regions, and discusses factors influencing the formation of it in this archipelago. Cluster analyses of similarity indices for both reptiles and amphibians indicate that the Ryukyu herpetofauna is strongly influenced by geohistory of this archipelago involving long isolation especially in its north-central part (i.e., southern Tokara, Amami, and Okinawa Groups). Correlation analyses suggest that the faunal diversity on each island is significantly influenced by its habitat diversity as reflected by the island area (for reptiles) or height (amphibians).

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The faunas of the living non-volant mammals in the Ryukyu Islands are geographically different among northern, central and southern islands, and the Senkaku Group. The Tokara Gap and the Kerama Gap are recognized as important borders of distributional ranges. The northern Ryukyu species are the same as those on the main-islands of Japan; probably they have been isolated only since the late Pleistocene. The central Ryukyu species include endemic elements that are considered as Miocene immigrants. The southern Ryukyu Islands has one endemic species, Prionailurus iriomotensis, which was possibly derived from the ancestral form of P. bengalensis in the middle Pleistocene. The Senkaku Group has two species, of which Nesoscaptor uchidai is endemic to this island group at the generic level. This mole may be closely related to Mogera insularis in Taiwan. The second species, Apodemus agrarius, is a continental species and probably immigrated in the late Pleistocene.

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Deer in the Kerama Island Group, Okinawa Prefecture, are generally regarded as an endemic form of the Japanese sika deer, with the subspecific name Cervus nippon keramae. Substantial morphological differences are recognized between C. n. keramae and other subspecies, although the Kerama population is believed to have originated from artificial introduction a few centuries ago. To clarify the degree of genetic divergence of C. n. keramae and discuss its origin, a partial sequence of the mitochondrial cytochrome-b gene was determined for deer from Akajima Island of the Kerama Group and was compared with those reported previously for other subspecies of the sika deer from southern Japan. Two individuals of C. n. keramae examined possessed two mtDNA haplotypes, of which one was shared with C. n. nippon and C. n. mageshimae from Kyushu and adjacent islands. The other, though differing from haplotypes so far reported for other subspecies, was also quite similar to haplotypes prevailing in other southern Japanese populations. These findings suggest that there is little genealogical separation between C. n. keramae and other subspecies from southern Japan.

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The Iriomote cat Felis iriomotensis is a small-sized felid species endemic to Iriomote Island, Japan. The population size of this cat seems to be only about 100, as estimated in both 1985 and 1995. This indicates that the population is stable but small. The Iriomote cat is categorized as “Endangered” on the Red Lists by IUCN (1996) and by the Environment Agency of Japan (1998). Habitat destruction and fragmentation, traffic accidents, negative influences of newly introduced animals, and the introduction and spread of exotic diseases seem to be the potential threats to the small insular population of the Iriomote cat. The Japanese Government recently initiated some programs for its conservation. In addition, collaborative projects have been organized by the government and university researchers for the purpose of collecting basic ecological data on this endangered species.

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The Amami rabbit Pentalagus [urnessi is an endemic species of the central Ryukyus, Japan, and occurs only on two islands, Amami Oshima I. and Tokunoshima I. For the conservation of this species, some research programs to reveal the population size, spatial and temporal patterns of activity, and impacts of introduced predators were carried out. The habitat available to the rabbit has obviously been reducing with considerable fragmentation on each island, and size of each population also seems to have been decreasing as well (2700-6500 in total of the two islands in 1995). The estimated home range size was relatively small (1.3 ha for males and 1.2 ha for females), and the rabbits moved 100-200 m from their burrows mainly during the night. The negative impact of the introduced mongoose on the rabbit was quite serious on Amami Oshima I., and effective control of this exotic predator is an urgent necessity for the conservation of the rabbit, as well as the whole ecosystem, of this island.

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We introduce a new immigration model in order to derive the famous power law on species-area (SA) relation for anisotropic island. This relation shows that the number of species is constrained not only by the size of the recipient island area or the species' dispersal capacity but also the power index of SA relation. Because this power index depends on island shapes, this means that island shape is one of the factor in constraining the number of species. From this viewpoint, we analyze an SA curve of the land snail fauna in forty-three islands in Ryukyu arc, Japan, and show that most individual species have travelled across the line of the island chain of the Ryukyu islands. Moreover, we reconsider the power index of SA relation in previous studies, and show that species have immigrated along the island chain by stepping-stone dispersal. We also consider the effect of the height of the surface topography on the species richness by using the Hurst parameter. Moreover, we point out that species richness and environmental heterogeneity have the same relationship with the area.

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The Mediterranean region, like other biogeographic regions located between continental plates, is rich in islands. Most of them are oceanic-like islands, Le., islands that have been previously connected to the surrounding continents and are faunistically similar, but not identical, to oceanic island (because the island - continent connections occurred in a distant past, were of a short duration, and/or promoted a highly selective and limited faunal transfer). Insular (Le., non-continental) vertebrate faunas are known in several Mediterranean islands from the Lower Miocene to Recent times. This paper presents an overview of these faunas in the Western and Central Mediterranean. I will emphasize the following points: 1. Island's geological succession in the western Mediterranean area. 2. Faunistic successions occurring on the different islands. 3. Global analysis of the Mediterranean insular faunas. 4. Record and analysis of some extreme cases of insular evolution. 5. Extinction of the Mediterranean insular faunas.
The Mediterranean region has changed substantially from Eocene to current times. A record of the transformation of Mediterranean islands during geological time is presented in this paper. Some territories that were islands in the past (e.g., Gargano, Scontrone, Baccinello, Las Murchas) have been integrated into the mainland and are now continental areas displaying insular fossil faunas. They are considered “fossil islands”. Merging of islands have also occurred (e.g., Mallorca, Sardinia, Crete) as well as some island splitting (e.g., Gymnesic islands).
In Sardinia, Mallorca, Menorca and Eivissa, there is a long fossil record documenting several faunistic successions. There, the faunistic turnover affected different taxonomic groups in different ways. Mammals were specially prone to extinction after new invasions.
The fossil insular vertebrate faunas from Mediterranean islands are peculiar. They differ both from typical oceanic insular faunas (usually devoid of mammals and amphibians) and the typical continental faunas (lacking endemic species). They are characterized by three main traits: (1) absence of mammal predators, (2) presence of terrestrial mammals and in some cases amphibians, and (3) high rates of endemic species, including some very bizarre taxa. Even though there are some exceptions, it is possible to define several global faunistic patterns for Mediterranean insular faunas.
also in assemblages of structures, implying substantial changes in the life style of the species). Some of the most noticeable insular evolutionary changes produced a variety of unusual taxa. Among amphibians, the subterranean Hydromantes from Sardinia, with four species still living on the island, displaying a ballistic chameleon-like retractile tongue, might be considered as examples. Among birds, the enormous owl Tyto gigantea, and the gigantic buteonine falcon Garganoaetus, as well as the terrestrial and probably flightless Cygnus falconeri. Among mammals, the bizarre Myotragus balearicus from the Pleistocene of the Gymnesic Islands (Mallorca and Menorca), a new genus of leporid, still undescribed, from the Pliocene of Menorca, the anthropomorph ape Oreopithecus bambolii from the Miocene of Baccinello (and Sardinia), Hoplitomeryx matthei and Deinogaleryx koenigswaldi from the Miocene of Gargano, and the dwarf hippo Phanourios minor from the Pleistocene in Cyprus, as well as some Pleistocene dwarf elephants and deer scattered over the Eastern and Central Mediterranean islands.1 Finally, the extinction of the insular vertebrate faunas is analyzed. Extinctions are usually related to faunistic turnover, but there are some exceptions. The last extinction wave corresponds to human colonization of the islands. Current faunas of the Mediterranean islands include mainly human introduced mammalian species, but they usually retain the herpetological endemic assemblage of Pleistocene faunas.

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Besides mass extinction, adaptive radiation is a common phenomenon, it can be found in all taxa. The scale of adaptive radiation depends on time and plasticity of the organism. The presence of several morphotypes or species of Pleistocene cervids on Crete is explained by De Vos (1996) as an adaptive radiation, in a one-invasion, one-radiation model. The Cretan deer became extinct at the arrival of man, about 8000 BP.

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The Indonesian Archipelago is situated between the Asian and the Australian continents. It is divided into the Sunda and the Sahul shelves and the Wallacea area in between. The Sunda and the Sahul shelves have been connected with the continents several times, as the result of tectonic movements and sea level fluctuations in Pleistocene time. On the other hand, the Wallacea area has never been connected to any continent. Asiatic faunas have migrated to Java, and some of them have even been able to cross over Wallace’s line by sweepstake dispersal. Thereafter, they adapted to island environments and developed into the unbalanced endemic island faunas. This paper gives an overview of the unbalanced endemic island faunas of the Indonesian archipelago.

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The two major island-arcs in the Caribbean Seanthe Greater and Lesser Antilles--have a long and complex history. A similar complexity attends the biogeographical history of the land vertebrates of these islands, concerning which there has been abundant argument but little resolution (e.g., Hedges, 1996; Page & Lydeard, 1996; Crother & Guyer, 1996; Iturralde-Vinent & MacPhee, 1999). The objective of this short review is (1) to examine some recent explorations of the problem of Antillean faunal formation, with special reference to new developments in the study of Antillean paleogeography; and (2) to chronicle the evidence for species diversification and depletion (i.e., radiation and extinction) in the West Indies, with special reference to the faunal catastrophes visited on these islands during the Quaternary period.

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To date, fossil deer (Ryukyu jika) Cervus astylodon (Matsumoto, 1926) occurs abundantly from Late Pleistocene fissure and cave deposits in four islands of the Ryukyu Islands : Tokunoshima, Okinawa, Kume, and Ishigaki. This study on Cervus astylodon from the comparative morphological viewpoint reveals that each of the four islands of the Ryukyu Islands yields a characteristic endemic morphotype.
Furthermore, on the island of Kume, several morphotypes can be distinguished. The four Kume morphotypes are characterized by different body-sizes and proportions of teeth and limb bones. These four morphotypes share characteristic metacarpal features, and demonstrate four phases in the dwarfing process. In the process of miniaturization, limb segments distal to the elbow and knee, exhibited a greater degree of dwarfing than did the humerus, femur, and mandibular teeth.
This process also indicates that dwarfism of Cervus astylodon in the Ryukyu Islands occurred bycontinuous morphological change in a relatively short period.
Consequently, morphotypes occur with higher frequency in insular than mainland environments. It is suggested that variation in size and form in deer is more likely to occur in limb bones, especially in metacarpal and metatarsal bones.

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Paleontological research for the Late Pleistocene (the last glacial maximum in general) fossil association of birds of the Central and Southern Ryukyu islands, which consists of forty-four species included in 17 families in 11 orders, revealed that the recent aspect of avian endemics, inhabiting one island only, is in fact due to relict palaeoendemism (Le., they are remnant distributions, left over from the extirpations on other island / area populations). Also, the fossil distribution of Oriental birds indicates that the recent northern limit of the Oriental zoogeographical region, Hachisuka’s line between the Southern and Central Ryukyus, is an “artificial” boundary that does not account for the vanished distributions. The forests of the Amamis and “Yambaru” in Okinawa are very important ecological habitats because they are, already, the result of local extinctions from the native one. We must take their present condition into consideration for the preservation of unique ecological habitats.

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Myotragus balearicus Bate, 1909 (Artiodactyla, Bovidae) is an endemic fossil Caprinae that lived until human arrival in the Balearic Islands (western Mediterranean Sea). Following the recent discovery of new deposits, some anatomical and ecological features of M balearicus were studied. Its diet, consisting mainly of Buxus balearica, a poisonous plant nowadays relictual in these islands, and its peculiar dentition, including a sole incisor in each dentary that has been identified as the second primary incisor tooth (d(₂), are among the recent findings concerning this species. This paper updates studies made on M. balearicus since 1985.

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