| Mececyon Temporal range: Pleistocene | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Canidae |
| Genus: | † Mececyon |
| Species: | †M. trinilensis |
| Binomial name | |
| †Mececyon trinilensis Stremme, 1911 | |
Mececyon trinilensis, the Trinil dog, is an extinct canid species that lived on the island of Java in Indonesia during the Pleistocene. [1]
The body size of Mececyon trinilensis been estimated at around 6.8–17.1 kilograms (15–38 lb), [2] comparable to a dhole. [3] This small size is the result of insular dwarfism. [2]
Mececyon trinilensis is endemic to the island of Java. It was part of the Pleistocene Trinil Fauna of Java, which dates to the late Early-Middle Pleistocene. [2] Other animals of this Faunal assemblage were Bos palaesondaicus , the Indian muntjak (Muntiacus muntjak), Bubalus paleaeokerabau , the Dubois santeng and Stegodon trigonocephalus. Other predators of the Trinil Fauna were the Trinil tiger (Panthera tigris trinilensis) and the leopard cat (Prionailurus bengalensis). [4] [5]
Mececyon is suggested to have been a hypercarnivore. [2] It has been estimated that Mececyon trinilensis hunted prey of 1 kg to 10 kg, preferably 5 kg in size. However this number could vary, because it is yet unknown if the Mececyon trinilensis hunted in packs, or if carrion left over by the Trinil tiger influenced its feeding habits. [6] Likely prey included rats and birds. [2]
Mececyon trinilensis probably ultimately originated from the mainland Xenocyon , perhaps Xenocyon lycanoides , likely via the intermediate species Megacyon merriami, which is proportionally larger than mainland Xenocyon species, and known from older Early Pleistocene fossils on Java. [2] The similarly dwarfed Sardinian dhole (Cynotherium sardous) is also suggested to have evolved from Xenocyon. Its closest living relatives are the African wild dog (Lycaon pictus) and the dhole (Cuon alpinus). [7] Some authors have suggested sinking Mececyon and Megacyon into Xenocyon. [2]
During the early Middle Pleistocene, the extinct dhole species Cuon priscus arrived on Java. It has been suggested that C. priscus outcompeted M/X. trinilensis, resulting in its absence in younger deposits. [3]
The dhole is a canid native to Central, South, East and Southeast Asia. It is genetically close to species within the genus Canis, but distinct in several anatomical aspects: its skull is convex rather than concave in profile, it lacks a third lower molar and the upper molars possess only a single cusp as opposed to between two and four. During the Pleistocene, the dhole ranged throughout Asia, with its range also extending into Europe but became restricted to its historical range 12,000–18,000 years ago.
Stegodon is an extinct genus of proboscidean, related to elephants. It was originally assigned to the family Elephantidae along with modern elephants but is now placed in the extinct family Stegodontidae. Like elephants, Stegodon had teeth with plate-like lophs that are different from those of more primitive proboscideans like gomphotheres and mammutids. The oldest fossils of the genus are found in Late Miocene strata in Asia, likely originating from the more archaic Stegolophodon, subsequently migrating into Africa. While the genus became extinct in Africa during the Pliocene, Stegodon remained widespread in South, Southeast and East Asia until the end of the Pleistocene.
Dwarf elephants are prehistoric members of the order Proboscidea which, through the process of allopatric speciation on islands, evolved much smaller body sizes in comparison with their immediate ancestors. Dwarf elephants are an example of insular dwarfism, the phenomenon whereby large terrestrial vertebrates that colonize islands evolve dwarf forms, a phenomenon attributed to adaptation to resource-poor environments and lack of predation and competition.
Insular dwarfism, a form of phyletic dwarfism, is the process and condition of large animals evolving or having a reduced body size when their population's range is limited to a small environment, primarily islands. This natural process is distinct from the intentional creation of dwarf breeds, called dwarfing. This process has occurred many times throughout evolutionary history, with examples including various species of dwarf elephants that evolved during the Pleistocene epoch, as well as more ancient examples, such as the dinosaurs Europasaurus and Magyarosaurus. This process, and other "island genetics" artifacts, can occur not only on islands, but also in other situations where an ecosystem is isolated from external resources and breeding. This can include caves, desert oases, isolated valleys and isolated mountains. Insular dwarfism is one aspect of the more general "island effect" or "Foster's rule", which posits that when mainland animals colonize islands, small species tend to evolve larger bodies, and large species tend to evolve smaller bodies. This is itself one aspect of island syndrome, which describes the differences in morphology, ecology, physiology and behaviour of insular species compared to their continental counterparts.
Panthera tigris trinilensis, known as the Trinil tiger, is an extinct tiger subspecies dating from about 1.2 million years ago that was found at the locality of Trinil, Java, Indonesia. The fossil remains are now stored in the Dubois Collection of the National Museum of Natural History in Leiden, the Netherlands. Although these fossils have been found on Java, the Trinil tiger is probably not a direct ancestor of the Javan tiger. The Trinil tiger probably became extinct 50,000 years ago. The Bali tiger was also not closely related to the Trinil because of their time differences.
Hațeg Island was a large offshore island in the Tethys Sea which existed during the Late Cretaceous period, probably from the Cenomanian to the Maastrichtian ages. It was situated in an area corresponding to the region around modern-day Hațeg, Hunedoara County, Romania. Maastrichtian fossils of small-sized dinosaurs have been found in the island's rocks. It was formed mainly by tectonic uplift during the early Alpine orogeny, caused by the collision of the African and Eurasian plates towards the end of the Cretaceous. There is no real present-day analog, but overall, the island of Hainan is perhaps closest as regards climate, geology and topography, though still not a particularly good match. The vegetation, for example, was of course entirely distinct from today, as was the fauna.
The Sardinian dhole is an extinct insular canid which was endemic to what is now the Mediterranean islands of Sardinia and Corsica during the Middle-Late Pleistocene. It went extinct at the end of the Pleistocene around the time of human settlement of the islands.
Hippopotamus melitensis is an extinct hippopotamus from Malta. It lived during Middle-Late Pleistocene. It probably descended from Hippopotamus pentlandi from Sicily, which in turn probably descended from the common hippopotamus. Like Hippopotamus pentlandi, Hippopotamus melitensis is substantially smaller in size than H. amphibius as a result of insular dwarfism, having an estimated mass of approximately 900 kg, which is smaller than the 1100 kg estimated for H. pentlandi. The diet of H. melitensis is suggested to have been more generalist than Hippopotamus amphibius, likely as a result of limited resource diversity and lack of competition, as the only other large herbivore on the island was the dwarf elephant Palaeoloxodon mnaidriensis. The majority of findings of this species are from Għar Dalam, a cave on Malta famous for its Pleistocene fossil deposits.
Hippopotamus pentlandi is an extinct species of hippopotamus from Sicily, known from the late Middle Pleistocene to early Late Pleistocene. It is the largest of the insular dwarf hippos known from the Pleistocene of the Mediterranean, "at most 20% smaller than the mainland forms", with an estimated body mass of approximately 1100 kg. It is suggested that it arrived in Sicily between 250,000 and 150,000 years ago, probably descending from the modern hippopotamus, with an origin from Hippopotamus antiquus being less likely. In comparison to those species, the muzzle was shorter, the occipital and nasal regions were more developed, the mastoid process was enlarged, and the dental row was shortened, and the condyle of the mandible is low. In comparison to H. amphibius, the orbits are also elevated. It was present in Sicily until at least the latest Middle Pleistocene around 120 kya, and was probably extinct by the beginning of Marine Isotope Stage 4. Contemporaneous species include the dwarf elephant Palaeoloxodon mnaidriensis, the aurochs, red deer, steppe bison, fallow deer, wild boar, brown bear, wolves, red foxes, cave hyena and cave lions. Its diet was likely grazing dominated, similar to that of modern H. amphibius. It is probably ancestral to Hippopotamus melitensis from Malta, which is substantially smaller than H. pentlandi.
The giant tapir is an extinct species of tapir that lived in southern China, Vietnam and Laos, with reports suggesting it also lived in Taiwan, Java, and potentially Borneo. The species has been recorded from Middle and Late Pleistocene. There is only weak evidence for a Holocene survival. Tapirus augustus was larger than any living tapir, with an estimated weight of about 623 kilograms (1,373 lb). The species was also placed in its own genus of Megatapirus, however, it is now conventionally placed within Tapirus.
Xenocyon is an extinct group of canids, either considered a distinct genus or a subgenus of Canis. The group includes Canis (Xenocyon) africanus, Canis (Xenocyon) antonii and Canis (Xenocyon) falconeri that gave rise to Canis (Xenocyon) lycanoides. The hypercarnivorous Xenocyon is thought to be closely related and possibly ancestral to modern dhole and the African wild dog, as well as the insular Sardinian dhole.
Hippopotamus creutzburgi, the Cretan dwarf hippopotamus, is an extinct species of hippopotamus from the island of Crete. It lived on the island from the Early Pleistocene to early Middle Pleistocene, and probably descended from Hippopotamus antiquus. It was considerably smaller than H. antiquus, weighing approximately 400 kilograms (880 lb). It was one of only two large herbivores on the island during its existence, alongside the dwarf mammoth Mammuthus creticus, with large predators being absent, the only other species of mammal present on the island being the giant rat Kritimys. It is known from abundant remains collected from the Katharo basin in the eastern uplands of Crete, approximately 1,100–1,200 metres (3,600–3,900 ft) above sea level, as well as much rarer remains found in coastal caves. Analysis of its limbs suggests that it was more adapted to terrestrial locomotion than living hippopotamus, primarily walking on its hooves rather than its footpads as in living hippopotamus, and capable of traversing the rugged terrain of Crete. Analysis of its teeth suggests that it had a grazing diet, similar to modern Hippopotamus amphibius. The previous suggestion that the species can be divided into two subspecies is not supported by modern research.
Palaeoloxodon mnaidriensis is an extinct species of dwarf elephant belonging to the genus Palaeoloxodon, native to the Siculo-Maltese archipelago during the late Middle Pleistocene and Late Pleistocene. It is derived from the European mainland straight-tusked elephant.
Protocyon is an extinct genus of large canid endemic to South and North America during the Late Pleistocene living from 781 to 12 thousand years ago.
Mammuthus creticus, or the Cretan dwarf mammoth, is an extinct species of dwarf mammoth endemic to Crete during the Early Pleistocene to early Middle Pleistocene.
Hemimachairodus is an extinct genus of machairodontine (sabre-toothed) cat with only one species, Hemimachairodus zwierzyckii, known from fossils from the Pleistocene of Java.
Megacyon merriami, or Merriam's dog, was a prehistoric canid that lived on the island of Java in Indonesia during the Early Pleistocene. Its scientific name means "Merriam's large dog".
Duboisia santeng or Dubois' antelope is an extinct antelope-like bovid that was endemic to Indonesia during the Pleistocene. It went extinct during the Ionian stage of the Pleistocene, about 750.000 years ago. Duboisia santeng was first described by the Dutch paleoanthropologist and geologist Eugène Dubois in 1891.
The Pseudodon shell DUB1006-fL or Pseudodon DUB1006-fL is a fossil freshwater shell of Pseudodon vondembuschianus trinilensis found at Trinil, Java, Indonesia. The shell has a zigzag engraving supposedly made by Homo erectus, which could be the oldest known anthropogenic engraving in the world.
Cervus astylodon, the Ryukyu dwarf deer, is an extinct species of dwarf deer that was endemic to the Ryukyu Islands of Okinawa, Ishigaki, Kume and Tokunoshima. It lived throughout the Pleistocene, becoming extinct towards the end of the Late Pleistocene, following the arrival of humans to the Ryukyu Islands.