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Evolution Of Macropodidae
The Macropodidae are an extant family of marsupial with the distinction of the ability to move bipedally on the hind legs, sometimes by jumping, as well as quadrupedally. They are herbivores, but some fossil genera like ''Ekaltadeta'' are hypothesised to have been carnivores.Stephen Wroe, Jenni Brammall, and Bernard N. Cooke "The Skull of ''Ekaltadeta ima'' (Marsupialia, Hypsiprymnodontidae?): An Analysis of Some Marsupial Cranial Features and a Reinvestigation of Propleopine Phylogeny, With Notes on the Inference of Carnivory in Mammals ''Journal of Paleontology''. 72(4), 1998, pp. 738-751 The taxonomic affiliations within the family and with other groups of marsupials is still in flux. Earliest macropods In Australia there are various fossil taxa described from the Oligocene–Miocene boundary from Riversleigh of Queensland, Lake Tarkarooloo, Namba, Etabunna and Wipajiri formations of South Australia.Cooke. B. N., "Cranial remains of a new species of Balbarine kangaroo (Mars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macropodidae
Macropodidae is a family of marsupials that includes kangaroos, wallabies, tree-kangaroos, wallaroos, pademelons, quokkas, and several other groups. These genera are allied to the suborder Macropodiformes, containing other macropods, and are native to the Australian continent (the mainland and Tasmania), New Guinea and nearby islands. Description Although omnivorous kangaroos lived in the past, modern macropods are herbivorous. Some are browsers, but most are grazers and are equipped with appropriately specialised teeth for cropping and grinding up fibrous plants, in particular grasses and sedges. In general, macropods have a broad, straight row of cutting teeth at the front of the mouth, no canine teeth, and a gap before the molars. The molars are large and, unusually, do not appear all at once but a pair at a time at the back of the mouth as the animal ages, eventually becoming worn down by the tough, abrasive grasses and falling out. Like many Macropodiformes, early ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potoroidae
Potoroidae is a family of marsupials, small Australian animals known as bettongs, potoroos, and rat-kangaroos. All are rabbit-sized, brown, jumping marsupials and resemble a large rodent or a very small wallaby. Taxonomy The potoroids are smaller relatives of the kangaroos and wallabies, and may be ancestral to that group. In particular, the teeth show a simpler pattern than in the kangaroo family, with longer upper incisors, larger canines, and four cusps on the molars. However, both groups possess a wide diastema between the incisors and the cheek teeth, and the potoroids have a similar dental formula to their larger relatives: In most respects, however, the potoroids are similar to small wallabies. Their hind feet are elongated, and they move by hopping, although the adaptations are not as extreme as they are in true wallabies, and, like rabbits, they often use their fore limbs to move about at slower speeds. The potoroids are, like nearly all diprotodonts, herbivorous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeopotorous
''Palaeopotorous priscus'' is a fossil species of a diprotodont marsupial, known from specimens obtained in central Australia. The animal was similar to the modern species of the family Potoroidae, the potoroos and bettongs. Taxonomy The only known species of its genus, ''Palaeopotorous'', which has been allied to the subfamily Potoroinae or as the type of a subfamily, Palaeopotoroinae, in the potoroid family. Description The dental evidence of the species indicates it was a similar size to a small to medium 'rat-kangaroos' that were common into the twentieth century. Since its first discovery, the species has been suspected of representing an early lineage of the macropods. The finds have been placed to the late Oligocene The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/ Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage ... pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulungamayinae
Bulungamayinae is a subfamily that allies fossil species of marsupials, showing close morphological features found in the modern potoroines, the bettongs and potoroos of Australia. The group possess characteristics of their dentition that place them in an alliance with the modern potoroos, smaller long nosed fungivores that dig and burrow. The premolars and incisors resemble the other potoroines, yet the molars accord with the herbivorous macropodids such as the kangaroos. Other characteristics of the ancestral group are found the two divergent families, and they were larger than modern potoroine species at around five to ten kilograms in weight, slightly more than the largest, the species ''Aepyprymnus rufescens''. The genera within the subfamilial arrangement of Potoroidae may be summarised as follows, * family Potoroidae :* subfamily †Palaeopotoroinae :* subfamily Potoroinae Potoroidae is a family of marsupials, small Australian animals known as bettongs, potoroos, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sthenurinae
Sthenurinae (from ''Sthenurus'', Greek for 'strong-tailed') is a subfamily within the marsupial family Macropodidae, known as 'short faced kangaroos'. No members of this subfamily are extant today, with all becoming extinct by the late Pleistocene. '' Procoptodon goliah'', the largest macropodid known to have existed, was a sthenurine kangaroo, but sthenurines occurred in a range of sizes, with ''Procoptodon gilli'' being the smallest at the size of a small wallaby. The short, robust skull of sthenurines is considered to be indicative that they were browsers that fed on leaves. Some species may have been able to reach above their heads and grasp branches with their semiopposable paws to assist in procuring leaves from trees. A single hoofed digit is present on the feet of sthenurines. Taxonomy The subfamilial arrangement Sthenurinae was circumscribed by Ludwig Glauert in 1926. Locomotion Unlike modern macropodids, which hop (either bipedally or quadrupedally), sthenurines seem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tingamarra Fauna
The Tingamarra Fauna is associated with the early Eocene Murgon fossil site, and contains the earliest known non-flying eutherian, passerine, trionychidae turtles, mekosuchine crocodiles along with frogs, lungfish and teleost fish in Australia. The Murgon fossil site is located near Kingaroy in south-east Queensland (26° 14' S, 151° 57' E). Geology Material that represents the fossil component is the MP1 horizon in a sequence of lacustrine clays from Boat Mountain. The geological formation of the site is not known for certain, but may be associated with the Oakdale Sandstone formation. The area was a swamp or shallow lake at the time of deposition, though the habitat has not been determined. Potassium-argon dating of illite Illite is a group of closely related non-expanding clay minerals. Illite is a secondary mineral precipitate, and an example of a phyllosilicate, or layered alumino-silicate. Its structure is a 2:1 sandwich of silica tetrahedron (T) – alumina ...s has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiomorphic
In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and synapomorphy, all mean a trait shared between species because they share an ancestral species. Apomorphic and synapomorphic characteristics convey much information about evolutionary clades and can be used to define taxa. However, plesiomorphic and symplesiomorphic characteristics cannot. The term ''symplesiomorphy'' was introduced in 1950 by German entomologist Willi Hennig. Examples A backbone is a plesiomorphic trait shared by birds and mammals, and does not help in placing an animal in one or the other of these two clades. Birds and mammals share this trait because both clades are descended from the same far distant ancestor. Other clades, e.g. snakes, lizards, turtles, fish, frogs, all have backbones and none are either birds no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
