Dasornis
Encyclopedia
Dasornis is a genus
of the prehistoric pseudotooth birds. These were probably rather close relatives of either pelican
s and stork
s, or of waterfowl
, and are here placed in the order
Odontopterygiformes to account for this uncertainty.
Almost all known material of this bird is from some 50 million years ago (Ma) and has been recovered from the Ypresian
(Early Eocene) London Clay
of the Isle of Sheppey
(England
). The exception are a few approximately 45 Ma-old remains from the Lutetian
(Middle Eocene, MP11-13
) of Etterbeek
(Belgium
) that are only tentatively included here, and some even more conjectural remains from outside Europe
(see below).
s – though still far more than of the average pseudotooth bird genus – are in decent condition. Among these is a superbly preserved partial skull that has been of crucial importance in sorting out the convoluted synonymy of this genus. Apart from that and another not quite as well-preserved partial skull, however, a number of beak
and cranium pieces as well as a few broken remains of wing
and tarsometatarsus
bones make up the known remains of Dasornis. The most tell-tale characteristic of the present genus are the combination of Paleogene
age and huge size. But given the fragmented state of these, it is not at all clear whether the genus was restricted to the North Atlantic (and perhaps the adjacent Paratethys
) or occurred also in the Pacific and in the Southern Hemisphere
, where fossils of a similar size were found (see below).
This genus belongs to the group of huge pseudotooth birds, with wingspan
s in excess of 5 m (16.4 ft), and probably as much as 6 m (19.7 ft). The complete head and bill probably measured almost 45 cm (1.5 ft) in life, the eye socket had a diameter of 55 millimetres (2.2 in) and the humerus
at its distal end was about 35 millimetres (1.4 in) wide. The well-preseved skull fossil shows deep grooves along the underside of the upper bill, with pits to accommodate the lower bill's "teeth". Thus, only the upper "teeth" were visible when the bird closed its bill. Dasornis resembles the much smaller Odontopteryx in having a jugal
arch that is mid-sized, tapering and stout behind the orbit
al process of the prefrontal bone
, unlike in the large Neogene
Osteodontornis
. Also, its paroccipital process is much elongated back- and downwards, again like in Odontopteryx but unlike in Pseudodontornis longirostris
. Further traits in which Dasornis agreed with Odontopteryx – and differed from Pelagornis
(a contemporary of Osteodontornis) are a deep and long handward-pointing pneumatic foramen in the fossa pneumotricipitalis of the humerus
, a latissimus dorsi muscle
attachment site on the humerus that consists of two distinct segments instead of a single long, and a large knob that extends along the ulna
where the ligamentum collateralis ventralis attached. As the traits as found in Odontopteryx and Dasornis are probably plesiomorphic, they cannot be used to argue for a closer relationship between the two Paleogene genera than either had with Osteodontornis and/or Pelagornis.
, Dasornis emuinus, is accepted today. However, it has a very convoluted synonymy, with its fossil
remains assigned to no less than six genera
(of which two were invalid junior homonyms) and divided between at least four species – excluding spelling errors and invalid "corrections" – that were variously moved between these genera for almost 150 years:
1854-1890: "Lithornis" emuinus, "Megalornis" of Seeley, Dasornis and Argillornis
The first fossil of D. emuinus, a piece of right humerus
shaft, was found in the Ypresian
(Early Eocene) London Clay
of the Isle of Sheppey
(England
). It was misidentified as a tibiotarsus
of the paleognath Lithornis
and described as L. emuinus by James Scott Bowerbank
in 1854. Harry Govier Seeley recognized this error in 1866 and established the genus Megalornis, though he misspelled the specific name as emuianus. However, the genus name he chose had already been used for some of the great herons
(Ardea). Richard Owen
established the genera Dasornis (in 1870) and Argillornis (in 1878) for, respectively, a broken skull and two humerus ends that were found in the same deposits. Some authors claim he erected the former genus in 1869 already, but in that year he only used the names informally in his brief initial report on the newly discovered skull. Misled by the skull's large size and perhaps overly eager to be the first to describe the remains of an "European moa
" (Owen was the foremost authority on these New Zealand
endemics at that time), he placed Dasornis in the Dinornithidae. Argillornis, on the other hand, was recognized early on as some sort of aquatic bird, but its immense size puzzled paleontologists to no little extent.
1891-1985: spelling errors, "Neptuniavis" and "completely unrealistic" taxonomy
Subsequent authors, noting that it was quite obviously not a paleognath ratite
, placed Dasornis in the Gastornithidae (diatrymas). Richard Lydekker
in 1891 proposed to rename Owen's D. londinensis to D. londiniensis, and later that year wanted to change Dasornis to Dasyornis. But the altered specific name was not in accordance with the rules of zoological nomenclature, and neither was the genus name he chose – and which, moreover, had already been used earlier by Nicholas Aylward Vigors
and Thomas Horsfield
for the bristlebird
s. In 1921, Kálmán Lambrecht "corrected" Seeley's Megalornis emuianus to emuinus and in 1933 he misspelled Owen's A. longipennis as longipes. Pierce Brodkorb
resolved the Megalornis homonymy in 1963 by merging "M." emuinus with A. longipennis, combining the older specific name emuinus and the then-valid genus name Argillornis. However, he rather inexplicably allied Argillornis with the enigmatic Mesozoic
Elopteryx nopcsai – a sort of "wastebin taxon
" for Late Cretaceous
maniraptora
n theropod remains from Romania
that might not even be of birds – and the mid-late Eocene
Eostega (probably a primitive gannet
). In 1976, Colin James Oliver Harrison and Cyril Alexander Walker finally determined all those remains to be of pseudotooth birds. They also proposed that part of the supposed A. longipennis remains was actually from a distinct and slightly smaller genus and species, which they described in a monotypic
genus as Macrodontopteryx oweni. In 1977, the same authors erected the genus Neptuniavis for supposed procellariiform tarsometatarsi also found on the Isle of Sheppey; they included two species there. Already however, eminent avian paleontologists such as Storrs L. Olson
were voicing their reservation about this proliferation of taxa in no uncertain terms.
2008: just Dasornis emuinus after all
Almost 150 years after the description of "L." emuinus, at the start of the 21st century, a rather well-preserved skull (lacking the beak
) was discovered, once again in the Isle of Sheppey London Clay. This specimen – SMNK-PAL 4017 – was studied by Gerald Mayr at the Senckenberg Museum
. He determined that all the large seabird
bones from the London Clay bones belonged to a single species of pelagornithid. To this, the scientific name Dasornis emuinus applies, a novel combination of the oldest valid genus and species names ever used for these fossils. Indeed, the importance of this specimen can hardly be underestimated, for the holotype
skull of Dasornis "londinensis" (which was used to establish the genus Dasornis) is so badly preserved that its status as a pseudotooth bird was debated as recently as 1985. Only the fossils named "Neptuniavis" minor were not of D. emuinus, but of the much smaller contemporary and sympatric pseudotooth bird Odontopteryx toliapica
.
"Dasornithidae"
The family
Dasornithidae was established by Harrison and Walker in 1976 for Dasornis and its presumed relatives, which are however nowadays included in the former. As current scientists generally try to avoid monotypic
taxa unless required by phylogeny, the Dasornithidae never were widely accepted; they are generally considered a junior synonym of the Pelagornithidae instead. And this seems to be quite correct indeed – as noted above, Pelagornis
, the type genus
of the Pelagornithidae, probably belongs to the same pseudotooth bird lineage as Dasornis and may even be descended from it. Thus, even if several families were recognized in the Odontopterygiformes, Pelagornis and Dasornis would almost certainly remain in the Pelagornithidae.
Dasornis are thus:
The junior synonyms of the species
D. emuinus are:
, described from a beak
piece and a damaged atlas
vertebra of what appears to have been a single individual, is yet another supposed pseudotooth bird species from the Early Eocene London Clay
of the Isle of Sheppey
. It may well be synonymous with D. emuinus too, or with Macrodontopteryx oweni if that is indeed a distinct species. This also applies to the Lutetian
(Middle Eocene) material from Etterbeek
(Belgium
) which was at first assigned to Argillornis (as was the holotype
skull of M. oweni); at least part of the supposed A. longipennis remains – though not its syntype
humerus
pieces – does seem to be rather small for D. emuinus. Perhaps Gigantornis
which is only known from pieces of a sternum
found in Middle Eocene rocks in Nigeria
also belongs in Dasornis; the sternum of D. emuinus remains unknown, but its size would have been a close match of the Nigerian fossil. Analysis of the unidentified large pelagornithid fossils from the Middle Eocene of Kpogamé-Hahotoé (Togo
) which are provisionally termed "Aequornis traversei" might shed light on this issue. The fairly large undescribed remains from the Late Paleocene/Early Eocene of the Ouled Abdoun Basin (Morocco
) which have been provisionally termed "Odontopteryx gigas
" may in fact be from a small or juvenile Dasornis. The same applies to M. oweni – nonwithstanding that it is sometimes placed in Odontopteryx –, considering it was for long included in Argillornis.
Also provisionally assigned to Argillornis were some pelagornithid wing bone remains, specimens LACM 128462 and presumably also LACM 127875 from the Keasey and Pittsburg Bluff Formations of the Eocene
/Oligocene
boundary of Oregon
. Whether this Pacific species was the same as the Atlantic D. emuinus is undetermined, but considering the age difference it is not all too likely and they may well belong to different genera. In that respect, the enigmatic Cyphornis magnus from the same region is most often assigned a Miocene age, but might actually be from around the Eo-Oligocene boundary as initially assumed; it or (if of Miocene age) an ancestor, or perhaps an ancestor of the Miocene genus Osteodontornis
, make a more plausible candidate for the Oregon fossils. Lack of sufficient well-preserved remains have prevented more detailed study however. Similar in size and age to the present genus are some pseudotooth bird remains from Antarctica, namely a jaw piece from the Middle/Late Eocene of the La Meseta Formation of Seymour Island
near the Drake Passage
, and a Middle Eocene piece of a humerus
shaft from Mount Discovery
on the continent's Pacific side. Separated from the North Atlantic by a wide distance and the equatorial currents, even in the case of the Seymour Island specimen it is doubtful whether they could be referred to Dasornis, because the fossils are simply too fragmentary.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of the prehistoric pseudotooth birds. These were probably rather close relatives of either pelican
Pelican
A pelican, derived from the Greek word πελεκυς pelekys is a large water bird with a large throat pouch, belonging to the bird family Pelecanidae....
s and stork
Stork
Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family Ciconiidae. They are the only family in the biological order Ciconiiformes, which was once much larger and held a number of families....
s, or of waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
, and are here placed in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Odontopterygiformes to account for this uncertainty.
Almost all known material of this bird is from some 50 million years ago (Ma) and has been recovered from the Ypresian
Ypresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between and , is preceded by the Thanetian age and is followed by the Eocene Lutetian age....
(Early Eocene) London Clay
London Clay
The London Clay Formation is a marine geological formation of Ypresian age which crops out in the southeast of England. The London Clay is well known for the fossils it contains. The fossils from the Lower Eocene indicate a moderately warm climate, the flora being tropical or subtropical...
of the Isle of Sheppey
Isle of Sheppey
The Isle of Sheppey is an island off the northern coast of Kent, England in the Thames Estuary, some to the east of London. It has an area of . The island forms part of the local government district of Swale...
(England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
). The exception are a few approximately 45 Ma-old remains from the Lutetian
Lutetian
The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between and . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene subepoch...
(Middle Eocene, MP11-13
Mammal Paleogene zone
The Mammal Paleogene zones or MP zones are biostratigraphic zones in the stratigraphic record of the Paleogene period of Europe. These zones were developed by Matthijs Freudenthal to help paleontologists provide more specific reference points to evolutionary events in Europe, but are used by...
) of Etterbeek
Etterbeek
Etterbeek is one of the nineteen municipalities located in the Brussels-Capital Region of Belgium. It neighbours the municipalities of the City of Brussels, Ixelles, Auderghem, Woluwe-Saint-Pierre, Woluwe-Saint-Lambert and Schaerbeek....
(Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
) that are only tentatively included here, and some even more conjectural remains from outside Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
(see below).
Description
Like those of its relatives, the thin-walled bones of Dasornis broke easily and thus very few fossilFossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s – though still far more than of the average pseudotooth bird genus – are in decent condition. Among these is a superbly preserved partial skull that has been of crucial importance in sorting out the convoluted synonymy of this genus. Apart from that and another not quite as well-preserved partial skull, however, a number of beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
and cranium pieces as well as a few broken remains of wing
Wing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...
and tarsometatarsus
Tarsometatarsus
The tarsometatarsus is a bone that is found in the lower leg of certain tetrapods, namely birds.It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsal and metatarsal bones...
bones make up the known remains of Dasornis. The most tell-tale characteristic of the present genus are the combination of Paleogene
Paleogene
The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...
age and huge size. But given the fragmented state of these, it is not at all clear whether the genus was restricted to the North Atlantic (and perhaps the adjacent Paratethys
Paratethys
The Paratethys ocean, Paratethys sea or just Paratethys was a large shallow sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in western Asia. The sea was formed during the Oxfordian epoch as an extension of the rift that formed the Central Atlantic Ocean and...
) or occurred also in the Pacific and in the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
, where fossils of a similar size were found (see below).
This genus belongs to the group of huge pseudotooth birds, with wingspan
Wingspan
The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...
s in excess of 5 m (16.4 ft), and probably as much as 6 m (19.7 ft). The complete head and bill probably measured almost 45 cm (1.5 ft) in life, the eye socket had a diameter of 55 millimetres (2.2 in) and the humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
at its distal end was about 35 millimetres (1.4 in) wide. The well-preseved skull fossil shows deep grooves along the underside of the upper bill, with pits to accommodate the lower bill's "teeth". Thus, only the upper "teeth" were visible when the bird closed its bill. Dasornis resembles the much smaller Odontopteryx in having a jugal
Jugal
The jugal is a skull bone found in most reptiles, amphibians, and birds. In mammals, the jugal is often called the malar or Zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species....
arch that is mid-sized, tapering and stout behind the orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
al process of the prefrontal bone
Prefrontal bone
The prefrontal bone is a bone separating the lacrimal and frontal bones in many tetrapod skulls. It first evolved in the sarcopterygian clade Rhipidistia, which includes lungfish and the Tetrapodomorpha. The prefrontal is found in most modern and extinct lungfish, amphibians and reptiles...
, unlike in the large Neogene
Neogene
The Neogene is a geologic period and system in the International Commission on Stratigraphy Geologic Timescale starting 23.03 ± 0.05 million years ago and ending 2.588 million years ago...
Osteodontornis
Osteodontornis
Osteodontornis is an extinct seabird genus. It contains a single named species, Osteodontornis orri , which was described quite exactly one century after the first species of the Pelagornithidae was. O...
. Also, its paroccipital process is much elongated back- and downwards, again like in Odontopteryx but unlike in Pseudodontornis longirostris
Pseudodontornis
Pseudodontornis is a rather disputed genus of the prehistoric pseudotooth birds. The pseudotooth birds or pelagornithids 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 uncertainty...
. Further traits in which Dasornis agreed with Odontopteryx – and differed from Pelagornis
Pelagornis
Pelagornis is a widely-known genus of the prehistoric pseudotooth birds. 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 uncertainty....
(a contemporary of Osteodontornis) are a deep and long handward-pointing pneumatic foramen in the fossa pneumotricipitalis of the humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
, a latissimus dorsi muscle
Latissimus dorsi muscle
The latissimus dorsi , meaning 'broadest muscle of the back' , is the larger, flat, dorso-lateral muscle on the trunk, posterior to the arm, and partly covered by the trapezius on its median dorsal region.The latissimus dorsi is responsible for extension,...
attachment site on the humerus that consists of two distinct segments instead of a single long, and a large knob that extends along the ulna
Ulna
The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...
where the ligamentum collateralis ventralis attached. As the traits as found in Odontopteryx and Dasornis are probably plesiomorphic, they cannot be used to argue for a closer relationship between the two Paleogene genera than either had with Osteodontornis and/or Pelagornis.
Systematics and taxonomy
Only a single speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, Dasornis emuinus, is accepted today. However, it has a very convoluted synonymy, with its fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
remains assigned to no less than six genera
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
(of which two were invalid junior homonyms) and divided between at least four species – excluding spelling errors and invalid "corrections" – that were variously moved between these genera for almost 150 years:
1854-1890: "Lithornis" emuinus, "Megalornis" of Seeley, Dasornis and Argillornis
The first fossil of D. emuinus, a piece of right humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
shaft, was found in the Ypresian
Ypresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between and , is preceded by the Thanetian age and is followed by the Eocene Lutetian age....
(Early Eocene) London Clay
London Clay
The London Clay Formation is a marine geological formation of Ypresian age which crops out in the southeast of England. The London Clay is well known for the fossils it contains. The fossils from the Lower Eocene indicate a moderately warm climate, the flora being tropical or subtropical...
of the Isle of Sheppey
Isle of Sheppey
The Isle of Sheppey is an island off the northern coast of Kent, England in the Thames Estuary, some to the east of London. It has an area of . The island forms part of the local government district of Swale...
(England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
). It was misidentified as a tibiotarsus
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...
of the paleognath Lithornis
Lithornis
Lithornis is a genus of extinct paleognathous birds. Lithornis were able to fly well, but are closely related to today's tinamous and ratites ....
and described as L. emuinus by James Scott Bowerbank
James Scott Bowerbank
James Scott Bowerbank FRS was a British naturalist and palaeontologist.-Biography:Bowerbank was born in Bishopsgate, London, and succeeded in conjunction with his brother to his father's distillery, in which he was actively engaged until 1847.In early years astronomy and natural history,...
in 1854. Harry Govier Seeley recognized this error in 1866 and established the genus Megalornis, though he misspelled the specific name as emuianus. However, the genus name he chose had already been used for some of the great herons
Ardea (genus)
Ardea is a genus of herons. Linnaeus named this genus as the Great Herons, referring to the generally large size of these birds, typically 80–100 cm or more in length....
(Ardea). Richard Owen
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
established the genera Dasornis (in 1870) and Argillornis (in 1878) for, respectively, a broken skull and two humerus ends that were found in the same deposits. Some authors claim he erected the former genus in 1869 already, but in that year he only used the names informally in his brief initial report on the newly discovered skull. Misled by the skull's large size and perhaps overly eager to be the first to describe the remains of an "European moa
Moa
The moa were eleven species of flightless birds endemic to New Zealand. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about in height with neck outstretched, and weighed about ....
" (Owen was the foremost authority on these New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
endemics at that time), he placed Dasornis in the Dinornithidae. Argillornis, on the other hand, was recognized early on as some sort of aquatic bird, but its immense size puzzled paleontologists to no little extent.
1891-1985: spelling errors, "Neptuniavis" and "completely unrealistic" taxonomy
Subsequent authors, noting that it was quite obviously not a paleognath ratite
Ratite
A ratite is any of a diverse group of large, flightless birds of Gondwanan origin, most of them now extinct. Unlike other flightless birds, the ratites have no keel on their sternum—hence the name from the Latin ratis...
, placed Dasornis in the Gastornithidae (diatrymas). Richard Lydekker
Richard Lydekker
Richard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:...
in 1891 proposed to rename Owen's D. londinensis to D. londiniensis, and later that year wanted to change Dasornis to Dasyornis. But the altered specific name was not in accordance with the rules of zoological nomenclature, and neither was the genus name he chose – and which, moreover, had already been used earlier by Nicholas Aylward Vigors
Nicholas Aylward Vigors
Nicholas Aylward Vigors was an Irish zoologist and politician.Vigors was born at Old Leighlin, County Carlow. He studied at Trinity College, Oxford. He served in the army during the Peninsular War from 1809 to 1811. He then returned to Oxford, graduating with a B.A. in 1815 and in 1817 with an...
and Thomas Horsfield
Thomas Horsfield
Thomas Horsfield M. D. was an American physician and naturalist.Horsfield was born in Bethlehem, Pennsylvania, and studied medicine at the University of Pennsylvania. He was the grandson of Timothy Horsfield, Sr., a colonel and justice of the peace in Bethlehem, and a friend mentioned in Benjamin...
for the bristlebird
Bristlebird
The bristlebirds are a family, Dasyornithidae, of passerine bird. There are three species in one genus, Dasyornis. The family is endemic to Australia...
s. In 1921, Kálmán Lambrecht "corrected" Seeley's Megalornis emuianus to emuinus and in 1933 he misspelled Owen's A. longipennis as longipes. Pierce Brodkorb
Pierce Brodkorb
Pierce Brodkorb , also stated as William Pierce Brodkorb, was an American ornithologist and paleontologist....
resolved the Megalornis homonymy in 1963 by merging "M." emuinus with A. longipennis, combining the older specific name emuinus and the then-valid genus name Argillornis. However, he rather inexplicably allied Argillornis with the enigmatic Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
Elopteryx nopcsai – a sort of "wastebin taxon
Wastebin taxon
Wastebasket taxon is a term used in some taxonomic circles to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined by their lack of one or more distinct character states or by their not belonging to one or more other taxa...
" for Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
maniraptora
Maniraptora
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the dinosaurs that were more closely related to them than to Ornithomimus velox. It contains the major subgroups Avialae, Deinonychosauria, Oviraptorosauria and Therizinosauria. Ornitholestes and the Alvarezsauroidea...
n theropod remains from Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
that might not even be of birds – and the mid-late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
Eostega (probably a primitive gannet
Gannet
Gannets are seabirds comprising the genus Morus, in the family Sulidae, closely related to the boobies.The gannets are large black and white birds with yellow heads. They have long pointed wings and long bills. Northern gannets are the largest seabirds in the North Atlantic, with a wingspan of up...
). In 1976, Colin James Oliver Harrison and Cyril Alexander Walker finally determined all those remains to be of pseudotooth birds. They also proposed that part of the supposed A. longipennis remains was actually from a distinct and slightly smaller genus and species, which they described in a monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
genus as Macrodontopteryx oweni. In 1977, the same authors erected the genus Neptuniavis for supposed procellariiform tarsometatarsi also found on the Isle of Sheppey; they included two species there. Already however, eminent avian paleontologists such as Storrs L. Olson
Storrs L. Olson
Storrs Lovejoy Olson is an American biologist and ornithologist from the Smithsonian Institution. He is one of the world's foremost avian paleontologists....
were voicing their reservation about this proliferation of taxa in no uncertain terms.
2008: just Dasornis emuinus after all
Almost 150 years after the description of "L." emuinus, at the start of the 21st century, a rather well-preserved skull (lacking the beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
) was discovered, once again in the Isle of Sheppey London Clay. This specimen – SMNK-PAL 4017 – was studied by Gerald Mayr at the Senckenberg Museum
Senckenberg Museum
The Naturmuseum Senckenberg in Frankfurt is the second largest museum of natural history in Germany. It is particularly popular with children, who enjoy the extensive collection of dinosaur skeletons: Senckenberg boasts the largest exhibition of large dinosaurs in Europe. One particular treasure is...
. He determined that all the large seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
bones from the London Clay bones belonged to a single species of pelagornithid. To this, the scientific name Dasornis emuinus applies, a novel combination of the oldest valid genus and species names ever used for these fossils. Indeed, the importance of this specimen can hardly be underestimated, for the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
skull of Dasornis "londinensis" (which was used to establish the genus Dasornis) is so badly preserved that its status as a pseudotooth bird was debated as recently as 1985. Only the fossils named "Neptuniavis" minor were not of D. emuinus, but of the much smaller contemporary and sympatric pseudotooth bird Odontopteryx toliapica
Odontopteryx
Odontopteryx is a genus of the prehistoric 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 uncertainty....
.
"Dasornithidae"
The family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Dasornithidae was established by Harrison and Walker in 1976 for Dasornis and its presumed relatives, which are however nowadays included in the former. As current scientists generally try to avoid monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
taxa unless required by phylogeny, the Dasornithidae never were widely accepted; they are generally considered a junior synonym of the Pelagornithidae instead. And this seems to be quite correct indeed – as noted above, Pelagornis
Pelagornis
Pelagornis is a widely-known genus of the prehistoric pseudotooth birds. 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 uncertainty....
, the type genus
Type genus
In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
of the Pelagornithidae, probably belongs to the same pseudotooth bird lineage as Dasornis and may even be descended from it. Thus, even if several families were recognized in the Odontopterygiformes, Pelagornis and Dasornis would almost certainly remain in the Pelagornithidae.
Synonyms
The junior synonyms of the genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Dasornis are thus:
- Argillornis OwenRichard OwenSir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
, 1878 - "Dasornis" Owen, 1869 (nomen nudumNomen nudumThe phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
) - Dasyornis LydekkerRichard LydekkerRichard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:...
, 1891 (non VigorsNicholas Aylward VigorsNicholas Aylward Vigors was an Irish zoologist and politician.Vigors was born at Old Leighlin, County Carlow. He studied at Trinity College, Oxford. He served in the army during the Peninsular War from 1809 to 1811. He then returned to Oxford, graduating with a B.A. in 1815 and in 1817 with an...
& HorsfieldThomas HorsfieldThomas Horsfield M. D. was an American physician and naturalist.Horsfield was born in Bethlehem, Pennsylvania, and studied medicine at the University of Pennsylvania. He was the grandson of Timothy Horsfield, Sr., a colonel and justice of the peace in Bethlehem, and a friend mentioned in Benjamin...
, 1836: preoccupiedBristlebirdThe bristlebirds are a family, Dasyornithidae, of passerine bird. There are three species in one genus, Dasyornis. The family is endemic to Australia...
) - Megalornis Seeley, 1866 (non Gray, 1841: preoccupiedArdea (genus)Ardea is a genus of herons. Linnaeus named this genus as the Great Herons, referring to the generally large size of these birds, typically 80–100 cm or more in length....
) - Neptuniavis Harrison & C.A.Walker, 1977
The junior synonyms of the species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
D. emuinus are:
- Argillornis emuinus (Bowerbank, 1854)
- Argillornis longipennis Owen, 1878
- Argillornis longipes Lambrecht, 1933 (lapsusLapsusA lapsus is an involuntary mistake made while writing or speaking. According to Freud's early psychoanalytic theory, a lapsus represents a missed deed that hides an unconscious desire....
) - "Dasornis londinensis" Owen, 1869 (nomen nudumNomen nudumThe phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
) - Dasornis londinensis Owen, 1870
- Dasornis londiniensis LydekkerRichard LydekkerRichard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:...
, 1891 (unjustified emendation) - Lithornis emuinus BowerbankJames Scott BowerbankJames Scott Bowerbank FRS was a British naturalist and palaeontologist.-Biography:Bowerbank was born in Bishopsgate, London, and succeeded in conjunction with his brother to his father's distillery, in which he was actively engaged until 1847.In early years astronomy and natural history,...
, 1854 - Megalornis emuianus Seeley, 1866 (lapsus)
- Megalornis emuinus Lambrecht, 1921 (lapsus)
- Neptuniavis miranda Harrison & C.A.Walker, 1977
Other fossils perhaps belonging in Dasornis
"Pseudodontornis" longidentataPseudodontornis
Pseudodontornis is a rather disputed genus of the prehistoric pseudotooth birds. The pseudotooth birds or pelagornithids 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 uncertainty...
, described from a beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
piece and a damaged atlas
Atlas (anatomy)
In anatomy, the atlas is the most superior cervical vertebra of the spine.It is named for the Atlas of Greek mythology, because it supports the globe of the head....
vertebra of what appears to have been a single individual, is yet another supposed pseudotooth bird species from the Early Eocene London Clay
London Clay
The London Clay Formation is a marine geological formation of Ypresian age which crops out in the southeast of England. The London Clay is well known for the fossils it contains. The fossils from the Lower Eocene indicate a moderately warm climate, the flora being tropical or subtropical...
of the Isle of Sheppey
Isle of Sheppey
The Isle of Sheppey is an island off the northern coast of Kent, England in the Thames Estuary, some to the east of London. It has an area of . The island forms part of the local government district of Swale...
. It may well be synonymous with D. emuinus too, or with Macrodontopteryx oweni if that is indeed a distinct species. This also applies to the Lutetian
Lutetian
The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between and . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene subepoch...
(Middle Eocene) material from Etterbeek
Etterbeek
Etterbeek is one of the nineteen municipalities located in the Brussels-Capital Region of Belgium. It neighbours the municipalities of the City of Brussels, Ixelles, Auderghem, Woluwe-Saint-Pierre, Woluwe-Saint-Lambert and Schaerbeek....
(Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
) which was at first assigned to Argillornis (as was the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
skull of M. oweni); at least part of the supposed A. longipennis remains – though not its syntype
Syntype
In biological nomenclature, a syntype is a term used to indicate a specimen with a special status.In zoological nomenclature, a syntype is defined as "Each specimen of a type series from which neither a holotype nor a lectotype has been designated [Arts. 72.1.2, 73.2, 74]. The syntypes...
humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
pieces – does seem to be rather small for D. emuinus. Perhaps Gigantornis
Gigantornis
Gigantornis eaglesomei was a giant prehistoric bird, described from a fragmentary specimen from the Eocene of Nigeria. It was considered to be a representative of the albatross family , but was later referred to the bony-toothed birds,...
which is only known from pieces of a sternum
Sternum
The sternum or breastbone is a long flat bony plate shaped like a capital "T" located anteriorly to the heart in the center of the thorax...
found in Middle Eocene rocks in Nigeria
Nigeria
Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...
also belongs in Dasornis; the sternum of D. emuinus remains unknown, but its size would have been a close match of the Nigerian fossil. Analysis of the unidentified large pelagornithid fossils from the Middle Eocene of Kpogamé-Hahotoé (Togo
Togo
Togo, officially the Togolese Republic , is a country in West Africa bordered by Ghana to the west, Benin to the east and Burkina Faso to the north. It extends south to the Gulf of Guinea, on which the capital Lomé is located. Togo covers an area of approximately with a population of approximately...
) which are provisionally termed "Aequornis traversei" might shed light on this issue. The fairly large undescribed remains from the Late Paleocene/Early Eocene of the Ouled Abdoun Basin (Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
) which have been provisionally termed "Odontopteryx gigas
Odontopteryx
Odontopteryx is a genus of the prehistoric 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 uncertainty....
" may in fact be from a small or juvenile Dasornis. The same applies to M. oweni – nonwithstanding that it is sometimes placed in Odontopteryx –, considering it was for long included in Argillornis.
Also provisionally assigned to Argillornis were some pelagornithid wing bone remains, specimens LACM 128462 and presumably also LACM 127875 from the Keasey and Pittsburg Bluff Formations of the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
/Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
boundary of Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
. Whether this Pacific species was the same as the Atlantic D. emuinus is undetermined, but considering the age difference it is not all too likely and they may well belong to different genera. In that respect, the enigmatic Cyphornis magnus from the same region is most often assigned a Miocene age, but might actually be from around the Eo-Oligocene boundary as initially assumed; it or (if of Miocene age) an ancestor, or perhaps an ancestor of the Miocene genus Osteodontornis
Osteodontornis
Osteodontornis is an extinct seabird genus. It contains a single named species, Osteodontornis orri , which was described quite exactly one century after the first species of the Pelagornithidae was. O...
, make a more plausible candidate for the Oregon fossils. Lack of sufficient well-preserved remains have prevented more detailed study however. Similar in size and age to the present genus are some pseudotooth bird remains from Antarctica, namely a jaw piece from the Middle/Late Eocene of the La Meseta Formation of Seymour Island
Seymour Island
Seymour Island is an island in the chain of 16 major islands around the tip of the Graham Land on the Antarctic Peninsula. Graham Land is closer to continental land mass than any other part of that Antarctica. It lies within the section of the island chain that resides off the west side of the...
near the Drake Passage
Drake Passage
The Drake Passage or Mar de Hoces—Sea of Hoces—is the body of water between the southern tip of South America at Cape Horn, Chile and the South Shetland Islands of Antarctica...
, and a Middle Eocene piece of a humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
shaft from Mount Discovery
Mount Discovery
Mount Discovery is a conspicuous, isolated stratovolcano, lying at the head of McMurdo Sound and east of Koettlitz Glacier, overlooking the NW portion of the Ross Ice Shelf...
on the continent's Pacific side. Separated from the North Atlantic by a wide distance and the equatorial currents, even in the case of the Seymour Island specimen it is doubtful whether they could be referred to Dasornis, because the fossils are simply too fragmentary.