''Hypselornis'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

, most likely a

crocodilian Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...

, from the late

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

. Known only from a single

toe bone Toes are the digits (fingers) of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being ''digitigrade''. Humans, and other animals that walk on the soles of their feet, are described as being ''plant ...

, ''Hypselornis'' was originally mistakenly identified as a

ratite A ratite () is any of a diverse group of 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. The systematics ...

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

related to the living

cassowary Cassowaries ( tpi, muruk, id, kasuari) are flightless birds of the genus ''Casuarius'' in the order Casuariiformes. They are classified as ratites (flightless birds without a keel on their sternum bones) and are native to the tropical forest ...

before being re-identified as belonging to a large reptile, probably a crocodilian.

Discovery and naming

The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen of ''Hypselornis'' (no. 39733) was found in the late

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Siwalik Hills The Sivalik Hills, also known as the Shivalik Hills and Churia Hills, are a mountain range of the outer Himalayas that stretches over about from the Indus River eastwards close to the Brahmaputra River, spanning the northern parts of the India ...

of northern India, and was collected by

Proby Cautley Sir Proby Thomas Cautley, KCB (3 January 1802 – 25 January 1871), English engineer and palaeontologist, born in Stratford St Mary, Suffolk, is best known for conceiving and supervising the construction of the Ganges canal during East India ...

who presented it to the

Natural History Museum A natural history museum or museum of natural history is a scientific institution with natural history collections that include current and historical records of animals, plants, fungi, ecosystems, geology, paleontology, climatology, and more. ...

London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...

. This specimen consists of a single toe bone (phalanx), and was initially mistakenly thought to have been referred to '' Struthio asiaticus'' by

Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. His father was Gerard Wolfe Lydekker, ...

in 1879. This mistake was corrected by

palaeontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

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 ''Dromaius'' (from greek δρομαίυς "runner") is a genus of ratite present in Australia. There is one extant species, ''Dromaius novaehollandiae'' commonly known as the emu. In his original 1816 description of the emu, Louis Jean Pierre Vi ...

sivalensis'' (a purported species of

emu The emu () (''Dromaius novaehollandiae'') is the second-tallest living bird after its ratite relative the ostrich. It is endemic to Australia where it is the largest native bird and the only extant member of the genus ''Dromaius''. The emu' ...

from India also known from toe bones that themselves likely belong to an

ungulate Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, cam ...

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

). 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''). An

etymology Etymology ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the Phonological chan ...

for the name was never given by Lydekker, but one was offered by

ornithologist Ornithology is a branch of zoology that concerns the "methodological study and consequent knowledge of birds with all that relates to them." Several aspects of ornithology differ from related disciplines, due partly to the high visibility and th ...

Charles Wallace Richmond Charles Wallace Richmond (December 31, 1868 – May 19, 1932) was an American ornithologist. He is best remembered for a compilation of the Latin names of birds that is called the Richmond Index. Life and work He was born in Kenosha, Wisconsin an ...

as deriving from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

"''ὑψηλός''" (lofty, towering) and "''ὄρνις''" (bird).

Classification

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 Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Casuariidae. However, when the fossil was later examined by

Percy Lowe Percy Roycroft Lowe (2 January 1870 – 18 August 1948) was an English surgeon and ornithologist. Life Lowe was born at Stamford, Lincolnshire and studied medicine at Jesus College, Cambridge. He served as a civil surgeon in the Second Boer ...

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.

References

{{Taxonbar, from=Q60791479 Crocodilians Prehistoric pseudosuchian genera Pliocene reptiles of Asia Pliocene crocodylomorphs Fossil taxa described in 1891