''Macrodontopteryx'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of the

prehistoric Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins million years ago and the beginning of recorded history with the invention of writing systems. The use o ...

pseudotooth bird The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds. Their fossil remains have been found all over the world in rocks dating ...

s of somewhat doubtful validity. These animals were probably rather close relatives of either

pelican Pelicans (genus ''Pelecanus'') are a genus of large water birds that make up the family Pelecanidae. They are characterized by a long beak and a large throat pouch used for catching prey and draining water from the scooped-up contents before ...

s and

stork Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family Ciconiidae, and make up the order Ciconiiformes . Ciconiiformes previously included a number of other families, such as herons and ibise ...

s, or of

waterfowl Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...

, and are here placed in the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Odontopterygiformes to account for this uncertainty.

Description

Only a single

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, ''Macrodontopteryx oweni'', is known to date. Its remains were found in the

Ypresian In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

(Early Eocene)

London Clay The London Clay Formation is a Sediment#Shores and shallow seas, marine formation (geology), geological formation of Ypresian (early Eocene Epoch, c. 54-50 million years ago) age which outcrop, crops out in the southeast of England. The London C ...

of the

Isle of Sheppey The Isle of Sheppey is an island off the northern coast of Kent, England, neighbouring the Thames Estuary, centred from central London. It has an area of . The island forms part of the districts of England, local government district of Borough ...

(

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

), where they were deposited about 50 Ma (

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

) in the

Mammal Paleogene zone The Mammal Paleogene zones or MP zones are a system of biostratigraphic zones in the stratigraphic record used to correlate mammal-bearing fossil localities of the Paleogene period of Europe. It consists of thirty consecutive zones (numbered MP 1 ...

MP8-9. The

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 preserve ...

s were at first assigned to ''Argillornis longipennis'', which is nowadays recognized as

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

of ''

Dasornis emuinus ''Dasornis'' is a genus of prehistoric pseudotooth birds. These were probably close relatives of either pelicans and storks or waterfowl; they are placed in the order Odontopterygiformes to account for this uncertainty. Almost all known mater ...

'', a larger pseudotooth bird than ''M. oweni''. Due to the scarcity of their fossil remains, is not clear whether the pseudotooth bird species described as '' Pseudodontornis longidentata'' is not the same as ''M. oweni'', though its size suggests that it is more likely to be synonymous with ''D. emuinus''. In any case, ''Macrodontopteryx'' itself may well be no distinct genus but rather a large member of the contemporary and

sympatric In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

Odontopteryx ''Odontopteryx'' is a genus of the extinct pseudotooth birds or pelagornithids. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this u ...

'', or a young or small ''Dasornis''. The only known specimen ( BMNH A1) is an incomplete and rather crushed

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

with much all of the

beak The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for pecking, grasping, and holding (in probing for food, eating, manipulating and ...

missing. In the living animal it would have measured roughly 30–35 cm (one foot). The

wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingsp ...

was probably around .

Other supposed remains

If ''Macrodontopteryx'' is indeed a distinct genus, perhaps some pseudotooth bird fossils found in

Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it ...

(

Middle Eocene The Eocene ( ) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', ' Dawn') a ...

, MP11-13, about 45 Ma) deposits at

Etterbeek Etterbeek (; ) is one of the List of municipalities of the Brussels-Capital Region, 19 municipalities of the Brussels-Capital Region, Belgium. Located in the eastern part of the region, it is bordered by the municipalities of Auderghem, the Cit ...

(

Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...

) belong therein. Like the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

BMNH A1, they have been assigned to ''Argillornis longipennis'' in the past; at least some of the material placed in that

taxon In biology, a taxon (back-formation from ''taxonomy''; : 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 name and ...

at one time or another – but not its

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 o ...

humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

pieces – seems too small to be of an adult ''Dasornis''. An

Early Oligocene The Rupelian is, in the geologic timescale, the older of two age (geology), ages or the lower of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/series (stratigraphy), Series. It spans the time between . It is preceded b ...

( Stampian, MP21-23, about 32 Ma)

distal Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

radius In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

from

Hamstead, Isle of Wight : ''Hamstead should not be confused with any of the many places called Hampstead (disambiguation), Hampstead.'' Hamstead is a small rural settlement in the civil parish of Shalfleet, on the Isle of Wight. It is located about three miles east of ...

(England) was also assigned to ''Macrodontopteryx''. It is without doubt from a very large and flight-capable bird, but little else can be said about it. An equally old

cervical vertebra In tetrapods, cervical vertebrae (: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sauropsid s ...

fragment (specimen BMNH A-4413) and a toe phalanx from nearby Yarmouth were, mainly due to their size, believed to be related to the enigmatic large flightless bird (and presumed

ratite Ratites () are a polyphyletic group consisting of all birds within the infraclass Palaeognathae that lack keels and cannot fly. They are mostly large, long-necked, and long-legged, the exception being the kiwi, which is also the only nocturnal ...

) ''

Eleutherornis ''Eleutherornis cotei'' is an extinct flightless predatory cariamiform bird which lived during the Middle Eocene of France and Switzerland. Since the early 20th century, researchers have initially described the fossils of ''Eleutherornis'' as sep ...

''. They were described as '' Proceriavis martini'', but have never been compared in detail to pseudotooth bird fossils. It cannot be ruled out that ''Proceriavis'' belongs in the Pelagornithidae, but whether it would be a

of ''Macrodontopteryx'' is highly uncertain given the 20-million-year difference between the Isle of Sheppey and Isle of Wight material. Recent analysis suggests that the material referred to as '' Proceriavis'' is in fact

in nature.Agnolin et al, Unexpected diversity of ratites (Aves, Palaeognathae) in the early Cenozoic of South America: palaeobiogeographical implications Article in Alcheringa An Australasian Journal of Palaeontology · July 2016 DOI: 10.1080/03115518.2016.1184898

Footnotes

References

* (2005): Osteological evidence for sister group relationship between pseudo-toothed birds (Aves: Odontopterygiformes) and waterfowls (Anseriformes). ''

Naturwissenschaften ''The Science of Nature'', formerly ''Naturwissenschaften'', is a monthly peer-reviewed scientific journal published by Springer Science+Business Media covering all aspects of the natural sciences relating to questions of biological significance. I ...

'' 92(12): 586–591. (HTML abstract
Electronic supplement
(requires subscription) * (1989): Giant Late Eocene Marine Birds (Pelecaniformes: Pelagornithidae) from Northwestern Oregon. '' J. Paleontol.'' 63(6): 939–944
Abstract and first page text
* (2008): A skull of the giant bony-toothed bird Dasornis (Aves: Pelagornithidae) from the Lower Eocene of the Isle of Sheppey. ''

Palaeontology Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geo ...

'' 51(5): 1107–1116. (HTML abstract) * (2009): ''Paleogene Fossil Birds''. Springer-Verlag, Heidelberg & New York. * (1996): Tertiary avian localities of the United Kingdom. ''Acta Universitatis Carolinae: Geologica'' 39: 759–771
PDF fulltext
* (2002): ''Cenozoic Birds of the World, Part 1: Europe''. Ninox Press, Prague. PDF fulltext
!-- This should be treated with extreme caution as regards merging of species. Splits are usually good though. See also critical review in Auk121:623-627 here http://www.findarticles.com/p/articles/mi_qa3793/is_200404/ai_n9396879 --> * (2009): Evolution of the Cenozoic marine avifaunas of Europe. ''Annalen des Naturhistorischen Museums Wien A'' 111: 357–37
PDF fulltext
{{Taxonbar, from=Q15261147 Pelagornithidae Eocene birds Fossil taxa described in 1976 Extinct birds of Europe