''Vorombe'' is one of three genera of

elephant bird Elephant birds are members of the extinct ratite family Aepyornithidae, made up of flightless birds that once lived on the island of Madagascar. They are thought to have become extinct around 1000-1200 CE, probably as a result of human activity. ...

s, an extinct

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

of large ratite birds

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

. Originally considered to be large ''

Aepyornis ''Aepyornis'' is a genus of aepyornithid, one of three genera of ratite birds endemic to Madagascar until their extinction sometime around 1000 CE. The species ''A. maximus'' weighed up to , and until recently was regarded as the largest known ...

'' specimens, it is now thought ''Vorombe'' are the largest and heaviest birds known to have existed. The genus was erected in 2018 after a detailed

morphometric Morphometrics (from Greek μορϕή ''morphe'', "shape, form", and -μετρία ''metria'', "measurement") or morphometry refers to the quantitative analysis of ''form'', a concept that encompasses size and shape. Morphometric analyses are co ...

analysis.

Taxonomy and naming

''Vorombe titan'' was first described by

Charles William Andrews Charles William Andrews (30 October 1866 – 25 May 1924) F.R.S., was a British palaeontologist whose career as a vertebrate paleontologist, both as a curator and in the field, was spent in the services of the British Museum, Department of Ge ...

as ''Aepyornis titan'' in 1894, though it was later synonymized with the type species of ''Aepyornis'', ''A. maximus'', by American

paleontologist 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 ...

Pierce Brodkorb William Pierce Brodkorb (September 29, 1908, Chicago – July 18, 1992, Gainesville, Florida) was an American ornithologist and paleontologist. Interested in birds since childhood, he was taught to prepare birds at the age of 16. Later, he rec ...

in 1963. In 2018, James Hansford and Samuel Turvey, two researchers from the

Zoological Society of London The Zoological Society of London (ZSL) is a charity devoted to the worldwide conservation of animals and their habitats. It was founded in 1826. Since 1828, it has maintained the London Zoo, and since 1931 Whipsnade Park. History On 29 ...

, found that it was sufficiently distinct from ''Aepyornis'' based on genetic and morphological evidence and allocated the species to a new genus, ''Vorombe''. They also recognized ''Aepyornis ingens'' as a synonym of ''Vorombe titan''. The study by Hansford and Turvey is the first taxonomic reassessment of elephant birds in over 50 years. The

genus name Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

''Vorombe'' is derived from the Malagasy word ''vorombe'' meaning "big bird" while the specific name ''titan'' is derived 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 p ...

word ''Τιτάν'' (''Titan''), which refers to the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

gods that preceded the

Twelve Olympians upright=1.8, Fragment of a relief (1st century BC1st century AD) depicting the twelve Olympians carrying their attributes in procession; from left to right: Hestia (scepter), Hermes (winged cap and staff), Aphrodite (veiled), Ares (helmet and s ...

Specimens and features

The

syntype In biological nomenclature, a syntype is any one of two or more biological types that is listed in a description of a taxon where no holotype was designated. Precise definitions of this and related terms for types have been established as part of ...

series of ''Vorombe titan'' includes a

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates wit ...

( NHMUK A439) and

tibiotarsus The tibiotarsus is the large bone between the femur and the tarsometatarsus in the leg of a bird. It is the fusion of the proximal part of the tarsus with the tibia. A similar structure also occurred in the Mesozoic Heterodontosauridae. These s ...

(NHMUK A437) found in

Itampolo Itampolo is a town and commune ( mg, kaominina) in southwestern Madagascar. It belongs to the district of Ampanihy, which is a part of Atsimo-Andrefana Region. The population of the commune was estimated to be approximately 32,000 in 2001 commune ...

(Itampulu Vé),

, with the femur originally being the lectotype of ''Aepyornis ingens''. The femur of ''Vorombe'' is significantly larger than that of ''Aepyornis'' and ''

Mullerornis ''Mullerornis'' is a genus of extinct elephant birds (Aepyornithidae) of Madagascar. Description ''Mullerornis'' is smaller than the more well-known '' Aepyornis''. A bone possibly belonging to ''Mullerornis'' has been radiocarbon dated to abo ...

'' in all measurements. Notable features include enlarged proximal and distal ends, a more acute curvature in the medio-distal margin of the

femoral head The femoral head (femur head or head of the femur) is the highest part of the thigh bone (femur). It is supported by the femoral neck. Structure The head is globular and forms rather more than a hemisphere, is directed upward, medialward, and a l ...

(caput femoris), the presence of a marked lateral supracondylar ridge, and a medial condyle (condylus medialis) that is expanded medially and flatter than in ''Aepyornis''. The tibiotarsus is extremely large in comparison to ''Aepyornis'' and ''Mullerornis''. The proximal and distal ends are enlarged, particularly medio-laterally. It has a more marked narrowing transition into the shaft, which is narrower in proportion to the total length compared to ''Aepyornis''. The tarsometatarsus is significantly larger and more expanded medio-laterally than in other genera, mainly at the proximal and distal ends. The lateral portion of the proximal articular surface protrudes proximally to the medial portion, creating a prominently angled proximal articular surface similar to that of ''A. hildebrandti''. The tarsometatarsus is larger than ''Mullerornis'' in all measurements, and larger than ''Aepyornis'' in most measurements. Samples from two femora assigned to ''Vorombe titan'' (specimens

MNHN The French National Museum of Natural History, known in French as the ' (abbreviation MNHN), is the national natural history museum of France and a ' of higher education part of Sorbonne Universities. The main museum, with four galleries, is loca ...

MAD 364 and NHMUK A2142) were sent for accelerator mass spectrometer carbon-14 dating at the

Oxford Radiocarbon Accelerator Unit The Research Laboratory for Archaeology and the History of Art (RLAHA) is a laboratory at the University of Oxford, England which develops and applies scientific methods to the study of the past. It was established in 1955 and its first director wa ...

and calibrated using ShCal13. Both specimens were dated to the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

(3,680 to 2,352 BP).

Size

''Vorombe'' stood tall and weighed , with a mean of . This is greater than the mass estimates of other extinct Quaternary giant birds such as ''

Dinornis The giant moa (''Dinornis'') is an extinct genus of birds belonging to the moa family. As with other moa, it was a member of the order Dinornithiformes. It was endemic to New Zealand. Two species of ''Dinornis'' are considered valid, the North ...

'' (which was between ) and ''

Dromornis stirtoni ''Dromornis'' is a genus of large to enormous prehistoric birds. The species were flightless, possessing greatly reduced wing structures but with large legs, similar to the modern ostrich or emu. They were likely to have been predominantly, i ...

'' (between ) making it the largest known bird. The largest femur (MNHN MAD 368) measured by Hansford and Turvey could not be formally assigned to a

cluster may refer to: Science and technology Astronomy * Cluster (spacecraft), constellation of four European Space Agency spacecraft * Asteroid cluster, a small asteroid family * Cluster II (spacecraft), a European Space Agency mission to study t ...

(group) as it was incomplete. The specimen is thought to belong to ''Vorombe'' on the basis of its size. It had a least-shaft circumference of , which gives a weight estimate of , making it the largest known bird individual ever recorded. This is comparable to or greater than the mass estimates of the smallest (

insular dwarf 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 disti ...

) sauropod dinosaurs: '' Europasaurus'', at ; and ''

Magyarosaurus ''Magyarosaurus'' (" Magyar lizard") is a genus of dwarf sauropod dinosaur from late Cretaceous Period (early to late Maastrichtian) in Romania. It is one of the smallest-known adult sauropods, measuring only in length and in body mass. The t ...

'', between .

Ecology

''Vorombe titan'', ''Aepyornis maximus'' and ''Mullerornis modestus'' were found across much of Madagascar, and were sympatric in the

arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ...

spiny forests in the south, succulent woodlands in the southwest, and grassland/ subhumid forest mosaic in the Central Highlands. The significant size differences between the three

taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

indicates that they exploited different dietary niches and plant interactions. Elephant birds shared the Quaternary

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

s of Madagascar with dwarf hippos, giant lemurs and

giant tortoise Giant tortoises are any of several species of various large land tortoises, which include a number of extinct species, as well as two extant species with multiple subspecies formerly common on the islands of the western Indian Ocean and on the ...

References

{{Taxonbar, from=Q56759905 Elephant birds Extinct animals of Madagascar Birds described in 2018 Extinct monotypic bird genera

Taxonomy and naming

Specimens and features

Size

Ecology

See also

References