Hypselornis Temporal range: Late Pliocene | |
---|---|
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Crocodilia |
Genus: | † Hypselornis Lydekker, 1891 |
Species: | †H. sivalensis |
Binomial name | |
†Hypselornis sivalensis Lydekker, 1891 | |
Hypselornis is an extinct genus of fossil reptile, most likely a crocodilian, from the late Pliocene of India. Known only from a single toe bone, Hypselornis was originally mistakenly identified as a ratite bird related to the living cassowary before being re-identified as belonging to a large reptile, probably a crocodilian.
The holotype specimen of Hypselornis (no. 39733) was found in the late Pliocene aged Siwalik Hills of northern India, and was collected by Proby Cautley who presented it to the Natural History Museum in London. This specimen consists of a single toe bone (phalanx), and was initially mistakenly thought to have been referred to Struthio asiaticus by Richard Lydekker in 1879. This mistake was corrected by palaeontologist William Davies in 1880, who concluded that the phalanx was from the middle toe of a new species of ratite distinct from the contemporary Struthio asiaticus and Dromaius sivalensis (a purported species of emu from India also known from toe bones that themselves likely belong to an ungulate mammal). [1] [2]
Lydekker would later classify the fossil as "Genus, non det." in 1884, and in 1891 he referred the fossil to its own genus and species, Hypselornis sivalensis (despite using the same specific name, Lydekker named H. sivalensis as a new species independent of D. sivalensis). [3] [4] An etymology for the name was never given by Lydekker, but one was offered by ornithologist Charles Wallace Richmond as deriving from the Ancient Greek "ὑψηλός" (lofty, towering) and "ὄρνις" (bird). [5]
As indicated by the name, Hypselornis was originally interpreted as a fossil bird. It was first classified by Davies as belonging to a three-toe ratite similar to but distinct from emus and cassowaries, with a closer resemblance to the latter. Lydekker agreed with this classification when he named it as its own genus and included it within the family Casuariidae. [3]
However, when the fossil was later examined by ornithologist Percy Lowe in 1929, he concluded that the bone was certainly not from a bird and instead most likely belonged to a crocodilian. He based this conclusion through comparisons of the bone to those of ratites and a crocodile, and found Hypselornis to resemble those of crocodiles in a number of ways. The bone is much more proportionately stout compared to those of ratites, and its asymmetry is also inconsistent with the toe bones of ratites. Furthermore, it does not taper towards its tip as it would in most ratites, and is instead constricted in its centre like that of a crocodile's. Rowe further identified six more details of the bone that were inconsistent with ratites, but similar to those of crocodiles. However, he was unable to perform a more conclusive diagnosis of Hypselornis without further comparison to other fossil Indian crocodilians. This re-identification has since been maintained by later authors. [4] [2]
Casuarius is a genus of birds in the order Casuariiformes, whose members are the cassowaries. It is classified as a ratite and is native to the tropical forests of New Guinea, Aru Islands (Maluku), and northeastern Australia.
A ratite is any of a diverse group of mostly flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites.
Struthionidae is a family of flightless birds, containing the extant ostriches and their extinct relatives. The two extant species of ostrich are the common ostrich and Somali ostrich, both in the genus Struthio, which also contains several species known from Holocene fossils such as the Asian ostrich. The common ostrich is the more widespread of the two living species, and is the largest living bird species. The extinct genus Pachystruthio from the Late Pliocene-Early Pleistocene of Eurasia is one of the largest birds ever.
Dromaius is a genus of ratite present in Australia. There is one extant species, Dromaius novaehollandiae commonly known as the emu.
Ostriches are large flightless birds of the genus Struthio in the order Struthioniformes, part of the infra-class Palaeognathae, a diverse group of flightless birds also known as ratites that includes the emus, rheas, and kiwis. There are two living species of ostrich: the common ostrich, native to large areas of sub-Saharan Africa and the Somali ostrich, native to the Horn of Africa. The common ostrich was also historically native to the Arabian Peninsula, and ostriches were present across Asia as far east as Mongolia during the Late Pleistocene and possibly into the Holocene. They lay the largest eggs of any living land animal. With the ability to run at 70 km/h (43.5 mph), they are the fastest birds on land. They are farmed worldwide, particularly for their feathers as they are used as decoration and feather dusters. Their skin is also used for leather products. They are the heaviest living birds.
The Sivalik Hills, also known as the Shivalik Hills and Churia Hills, are a mountain range of the outer Himalayas that stretches over about 2,400 km (1,500 mi) from the Indus River eastwards close to the Brahmaputra River, spanning across the northern parts of the Indian subcontinent. It is 10–50 km (6.2–31.1 mi) wide with an average elevation of 1,500–2,000 m (4,900–6,600 ft). Between the Teesta and Raidāk Rivers in Assam is a gap of about 90 km (56 mi). "Sivalik" literally means 'tresses of Shiva'. Sivalik region is home to the Soanian archaeological culture.
The southern cassowary, also known as double-wattled cassowary, Australian cassowary or two-wattled cassowary, is a large flightless black bird. It is one of the three living species of cassowary, alongside the dwarf cassowary and the northern cassowary. It is a ratite and therefore related to the emu, ostriches, rheas and kiwis.
The Casuariiformes is an order of large flightless birds that has four surviving members: the three species of cassowary, and the only remaining species of emu. They are divided into either a single family, Casuariidae, or more typically two, with the emu splitting off into its own family, Dromaiidae.
The northern cassowary also known as the one-wattled cassowary, single-wattled cassowary, or golden-necked cassowary, is a large, stocky flightless bird of northern New Guinea. It is one of the three living species of cassowary, alongside the dwarf cassowary and the southern cassowary. It is a member of the superorder Paleognathae.
Palaeognathae is a infraclass of birds, called paleognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contains five extant branches of flightless lineages, termed ratites, and one flying lineage, the Neotropic tinamous. There are 47 species of tinamous, five of kiwis (Apteryx), three of cassowaries (Casuarius), one of emus (Dromaius), two of rheas (Rhea) and two of ostrich (Struthio). Recent research has indicated that paleognaths are monophyletic but the traditional taxonomic split between flightless and flighted forms is incorrect; tinamous are within the ratite radiation, meaning flightlessness arose independently multiple times via parallel evolution.
The Kangaroo Island emu or dwarf emu is an extinct subspecies of emu. It was restricted to Kangaroo Island, South Australia, which was known as Ile Decrés by the members of the Baudin expedition. It differed from the mainland emu mainly in its smaller size. The species became extinct by about 1827.
The Asian or Asiatic ostrich, is an extinct species of ostrich that lived during the Neogene period on the Indian subcontinent. The early records that ranged from the Pliocene epoch in Africa to Pleistocene-Holocene epoch in northeastern Asia are considered dubious. Beads made from shells taken from archaeological sites in India dating to more than 25,000 years were found to have traces of DNA and analysis of sequences examined from them show that the species is definitely in the genus Struthio.
Bird ichnology is the study of avian life traces in ornithology and paleontology. Such life traces can include footprints, nests, feces and coproliths. Scientists gain insight about the behavior and diversity of birds by studying such evidence.
Emuarius is an extinct genus of casuariiform flightless bird from Australia that lived during the early Miocene and late Oligocene. It is one of two known genera of emu. There are two known species in the genus, Emuarius gidju and Emuarius guljaruba. The birds in this genus are known as emuwaries. This name comes from a combination of emu and cassowary. This is due to its cassowary-like skull and femur and emu-like lower leg and foot. Because of these similarities it is phylogenetically placed between cassowaries and emus.
Eremopezus is a prehistoric bird genus, possibly a palaeognath. It is known only from the fossil remains of a single species, the huge and presumably flightless Eremopezus eocaenus. This was found in Upper Eocene Jebel Qatrani Formation deposits around the Qasr el Sagha escarpment, north of the Birket Qarun lake near Faiyum in Egypt. The rocks its fossils occur in were deposited in the Priabonian, with the oldest dating back to about 36 million years ago (Ma) and the youngest not less than about 33 Ma.
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Enhydriodon, known as the bear otter, is an extinct genus of typically large otters that lived in what is now Kenya, Ethiopia, Uganda, Chad, South Africa, and India from the late Miocene up to early Pleistocene. The otter is thought to be a relative of modern-day sea otters. E. omoensis and E. dikikae were described as the largest mustelids to have ever existed, though only fragments of the genus have been found such as the skull, femur, and dental remains in Ethiopia. Multiple estimates put them at about 200 kilograms (440 lb) while E. omoensis was described to be lion-sized, making them the largest mustelids described so far. Most species of the Enhydriodon genus are presumed to be semi-aquatic given most of the fossil isotope values being similar to fossilized semi-aquatic animals like hippopotamuses. The largest species, Enhydriodon omoensis, however, was determined to be a terrestrial predator, capable of hunting herbivorous terrestrial prey. Enhydriodon is part of the bunodont otters group, referring to otter genera with non-bladelike carnassials including the extant Enhydra genus and its extinct relatives that lived from the late Miocene to the early Pleistocene.
Enhydriodon dikikae is an extinct species in the family Mustelidae that existed during the Miocene and Pliocene epoch. Fossils from this species were discovered in Dikika, Lower Awash Valley in Ethiopia. These fossils were found in the lower basal member of the Hadar Formation, which means they existed more than 3.42 million years ago but the estimated age of the fossils is greater than 3.4 million years old and likely to be closer to 4 million years old. In comparison to most other species in the genus Enhydriodon, E. dikikae is one of the youngest.