Osteodontornis
Encyclopedia
Osteodontornis is an extinct seabird
genus
. It contains a single named species
, Osteodontornis orri (Orr's Bony-toothed Bird, in literal translation of its scientific name), which was described quite exactly one century after the first species of the Pelagornithidae
(Pelagornis miocaenus) was. O. orri was named after then-recently deceased naturalist Ellison Orr.
The bony-toothed or pseudotooth birds were initially believed to be related to albatross
es in the Procellariiformes
, but actually they seem to be 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. Also, their internal taxonomy
is not well-resolved. An earlier-described pseudotooth bird, Cyphornis magnus from Vancouver Island
(Canada
), was believed to be of Eocene
age but is nowadays assumed to have lived in the Early Miocene
, not too long before the Clarendonian
(Middle
/Late Miocene
) O. orri. It may be that Osteodontornis is a junior synonym of Cyphornis.
, though about as long as a human's, was only about 3.5 centimetres (1.4 in) wide at the shoulder end. The skull's quadrate bone
measured almost 30 millimetres (1.2 in) at its widest and was nearly 45 millimetres (1.8 in) high.
Like its relatives, O. orri had a stout but extremely light-boned body, feet that were presumably webbed as in its aquatic relatives, and long and probably very narrow wing
s resembling those of an albatross
. Its beak
made up about three-quarters of the head's length and had bony tooth
-like serrations that were hollow or maybe filled with cancellous bone. The beak was so heavy the creature probably held it between its shoulders while in flight, just like modern pelican
s do. The arrangement of its bony
serrations is characteristic for this genus: one small "tooth", flanked by small points or even smaller "teeth", is placed between each pair of large ones. However, the "tooth" pattern of pseudotooth birds changed along the length of the beak, and is not considered a very reliable way to distinguish genera
.
In general lifestyle, it was probably most similar to the albatross
es, tropicbird
s and frigatebird
s of today, with long slender wings adapted for soaring
vast distances over the open seas. Due to its size, the bird is presumed to have been an excellently adapted
dynamic soarer. It probably built its nest
on high plateau
s or similar places, where it could easily take flight by simply walking into the wind with wings spread. It was a seabird that apparently lived mainly off squid
and other soft-bodied prey; the "teeth" were less saw-like than the horny
serrations on the beak of the fish-eating saw-billed ducks (Merginae
), pointing straight downwards instead and in the fossils often very abraded or broken. The downward-pointing "teeth" were ideal for digging into and holding slippery, soft-skinned pelagic animals such as cephalopod
s that were probably snatched out of the water in flight or while swimming. Lightly built as it was, O. orri was probably not a good diver and may have found it impossible to dive at all.
Osteodontornis is one of the pseudotooth birds of which rather comprehensive remains are known, but the lack of good fossils of most other Odontopterygiformes allows for few direct comparisons between genera. Still, the distal humerus
of the present genus (e.g. the Barstovian
specimen LACM 50660 from Kern County, California
) can be compared to that of a smaller and older fossil tentatively assigned to Odontopteryx
. Osteodontornis has a wider and deeper notch between the external condyle and the ectepicondylar prominence, with the pit between these farther from the bone's end, than did the smallish Paleogene
species. Its quadrate bone
differed from that of Odontopteryx toliapica in a more narrowly grooved dorsal
head, and a larger and less forward-pointing orbit
al process. The forward center of the ventral articulation ridge extends upwards and forward, and the pterygoid process is conspicuously expanded to the upper center in Osteodontornis. The socket for the quadratojugal
has an intermediate position and the lateral ridge of the slender main shaft is straight and fairly thin. The quadrate of the mysterious Pseudodontornis longirostris skull (which some consider to belong in Pelagornis
) is not very well preserved; it agees with Odontopteryx in a broad main shaft and with Osteodontornis in the straight main shaft ridge and its upward-directed ventral articulation ridge's forward center. Otherwise, it differs from both.
is well documented from various locations of generally Miocene
age, although usually by much fragmented remains due to the thin and tender bones it had. Most importantly, it was found on both sides of the North Pacific. It is not certain whether all Osteodontornis remains belong to a single species; size differences suggest that some evolution
took place during the timespan in which the genus
existed. Thus, some fossils are referred to Osteodontornis only, without further assigning them to this species.
The type specimen of O. orri, SBMNH 309, is a rather comprehensive fossil preserved mostly as imprint, with some bone pieces and even feather impressions in addition; it was found in Clarendonian
(Late Miocene
) shale
of California
(USA). Subsequently, for example in the Barstovian
(Middle Miocene
) Round Mountain Silt or in Late Miocene deposits of the Monterey Formation
, quite a few additional specimens dating from about the same time were found in California. Roughly contemporary specimens were described from the Haranoyan-Tozawan boundary in Japan
– a complete right quadrate bone
(NSM
PV-18696) from the Middle Miocene Nagura Formation
at Chichibu, Saitama
, an Early Miocene
right mandible
piece (MFM 28351) found in the Oi Formation
at Misato, Mie
, and some additional material of about the same age from the Mizunami Group at Mizunami, Gifu
. From the Early Miocene Nye Formation and the Middle Miocene
Astoria Formations of Oregon
a handful of specimens that appear to be Osteodontornis are known. Similar fossils have been found in the Middle Miocene Capadare Formation of Venezuela
and from the Late Miocene of the Pisco Formation of Peru
; they might rather be of a distinct but closely related genus, and it must be remembered that at that their time the Isthmus of Panama
had not been formed yet so that an affiliation with the Atlantic Pelagornis
cannot be discounted. The former, specimen MBLUZ-P-5093 from Cueva del Zumbador in Falcón State, is a premaxilla
tip of immense dimensions; its bearer might have exceeded a wingspan of 7 metres (23 ft) in life. Though some of the Miocene North American material was initially (and sometimes is still) assigned to Pelagornis, recent authors generally place them in the present genus.
Some wing bone fossils from the Eo
-Oligocene
boundary of Oregon
(USA), though assigned to Argillornis (= Dasornis
), do not differ much from those of Osteodontornis (as far as can be told in their fragmented state), and may be from an older relative. They are the oldest known remains of large North Pacific pseudotooth birds, but if the enigmatic Cyphornis magnus from the same region dates back to the Paleogene
they may well be assignable to that taxon
, whatever their systematic
affiliations might be beyond that. As few directly comparable bones of sufficient quality exist, the relationship of Osteodontornis to other pseudotooth birds is not completely resolved. As noted above, the entire genus (regardless of how many species can be recognized) may be a junior synonym of Cyphornis. Generally, recent authors have tended to place large Neogene
pseudotooth bird fossils from the Atlantic in Pelagornis, and those from the North Pacific in Osteodontornis. It remains to be seen if this east-west division can be upheld, but biogeographically it seems quite sensible at least as a working hypothesis
until sufficient well-preserved material has been found to make an in-depth study. It is less clear what to make of the Southern Hemisphere
pseudotooth birds fossils, none of which are complete enough for more than the most tentative identification. Many seabird
s of our time, such as albatross
es and other Procellariiformes
, show a phylogenetic division between Northern and Southern Hemisphere lineages, separated by the Equatorial current
s. Whether this also held true in the warmer climate
of the Miocene
is not known, but the general phylogenetic patterns found in Procellariiformes suggests that the north-south division is rather ancient and evolved even before the Miocene.
From the Neogene of New Zealand
"Pseudodontornis" stirtoni
has been described, which unlike the rest of its (doubtfully valid) genus is not from the Paleogene Atlantic region. It has been proposed as a monotypic
genus Neodontornis, but this has not been widely accepted. It may be valid still, as the bones are of a rather small pseudotooth bird; though apparently too small for Osteodontornis detailed comparisons could be insightful. Its jugal
arch is indeed short and very stout behind the orbit
al process of the prefrontal bone
, like in Osteodontornis but apparently unlike in the type species
of its supposed genus, P. longirostris. A larger proximal (initially misidentified as distal) humerus piece (CMNZ AV 24,960), probably from the Waiauan (Middle/Late Miocene) and found near the Waipara River
mouth, is little if any distinct from O. orri in shape and size; it has a flange at the side and is less straight, but whether these features are natural or due to the damaged state of the specimens is unclear. It also agrees more with Pelagornis than with Paleogene remains from Oregon mentioned above. A distal left humerus end and some wing bone fragments from the Late Oligocene Yamaga Formation
of Kitakyūshū (Japan) might be the oldest remains of an Osteodontornis, but their assignment to the present genus is just as uncertain as in the case of the New Zealand fossil. Also from Japan are one or two of the youngest pseudodontorn fossils – a fragmentary right humerus from the Early Pliocene Yushima Formation
at Maesawa
, and probably also a distal right femur
(MFM 1801) from the Early Pleistocene
Dainichi Formation
at Kakegawa that was initially believed to be from an albatross. These might represent the last survivors of Osteodontornis – the Kakegawa fossil at least is a good match in size –, but require more study before they can be assigned there.
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...
genus
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...
. It contains a single named 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...
, Osteodontornis orri (Orr's Bony-toothed Bird, in literal translation of its scientific name), which was described quite exactly one century after the first species of the Pelagornithidae
Pelagornithidae
The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds...
(Pelagornis miocaenus) was. O. orri was named after then-recently deceased naturalist Ellison Orr.
The bony-toothed or pseudotooth birds were initially believed to be related to albatross
Albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes . They range widely in the Southern Ocean and the North Pacific...
es in the Procellariiformes
Procellariiformes
Procellariiformes is an order of seabirds that comprises four families: the albatrosses, petrels and shearwaters, storm petrels, and diving petrels...
, but actually they seem to be 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. Also, their internal taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
is not well-resolved. An earlier-described pseudotooth bird, Cyphornis magnus from Vancouver Island
Vancouver Island
Vancouver Island is a large island in British Columbia, Canada. It is one of several North American locations named after George Vancouver, the British Royal Navy officer who explored the Pacific Northwest coast of North America between 1791 and 1794...
(Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
), was believed to be of 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...
age but is nowadays assumed to have lived in the Early Miocene
Early Miocene
The Early Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages....
, not too long before the Clarendonian
Clarendonian
The Clarendonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 13,600,000 to 10,300,000 years BP, a period of . It is usually considered to overlap the Serravallian of the Middle...
(Middle
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene....
/Late Miocene
Late Miocene
The Late Miocene is a sub-epoch of the Miocene Epoch made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch....
) O. orri. It may be that Osteodontornis is a junior synonym of Cyphornis.
Description
With a wingspan of 5.5 to 6 m (18 to 19.7 ft) and a height of 1.2 metres (3.9 ft) when on the ground, Osteodontornis orri and similar giant pseudotooth birds were the second-largest flying birds known, surpassed only by the teratorn Argentavis magnificens. The head, from neck to bill-tip, measured about 40 centimetres (1.3 ft), and the eyesockets were about 5.3 centimetres (2.1 in) wide. The humerusHumerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
, though about as long as a human's, was only about 3.5 centimetres (1.4 in) wide at the shoulder end. The skull's quadrate bone
Quadrate bone
The quadrate bone is part of a skull in most tetrapods, including amphibians, sauropsids , and early synapsids. In these animals it connects to the quadratojugal and squamosal in the skull, and forms part of the jaw joint .- Evolutionary variation :In snakes, the quadrate bone has become elongated...
measured almost 30 millimetres (1.2 in) at its widest and was nearly 45 millimetres (1.8 in) high.
Like its relatives, O. orri had a stout but extremely light-boned body, feet that were presumably webbed as in its aquatic relatives, and long and probably very narrow 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...
s resembling those of an albatross
Albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes . They range widely in the Southern Ocean and the North Pacific...
. Its 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...
made up about three-quarters of the head's length and had bony tooth
Tooth
Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...
-like serrations that were hollow or maybe filled with cancellous bone. The beak was so heavy the creature probably held it between its shoulders while in flight, just like modern 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 do. The arrangement of its bony
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
serrations is characteristic for this genus: one small "tooth", flanked by small points or even smaller "teeth", is placed between each pair of large ones. However, the "tooth" pattern of pseudotooth birds changed along the length of the beak, and is not considered a very reliable way to distinguish 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...
.
In general lifestyle, it was probably most similar to the albatross
Albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes . They range widely in the Southern Ocean and the North Pacific...
es, tropicbird
Tropicbird
Tropicbirds are a family, Phaethontidae, of tropical pelagic seabirds now classified in their own order Phaethontiformes. Their relationship to other living birds is unclear, and they appear to have no close relatives. There are three species in one genus, Phaethon...
s and frigatebird
Frigatebird
The frigatebirds are a family, Fregatidae, of seabirds. There are five species in the single genus Fregata. They are also sometimes called Man of War birds or Pirate birds. Since they are related to the pelicans, the term "frigate pelican" is also a name applied to them...
s of today, with long slender wings adapted for soaring
Bird flight
Flight is the main mode of locomotion used by most of the world's bird species. Flight assists birds while feeding, breeding and avoiding predators....
vast distances over the open seas. Due to its size, the bird is presumed to have been an excellently adapted
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
dynamic soarer. It probably built its nest
Nest
A nest is a place of refuge to hold an animal's eggs or provide a place to live or raise offspring. They are usually made of some organic material such as twigs, grass, and leaves; or may simply be a depression in the ground, or a hole in a tree, rock or building...
on high plateau
Plateau
In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...
s or similar places, where it could easily take flight by simply walking into the wind with wings spread. It was a seabird that apparently lived mainly off squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
and other soft-bodied prey; the "teeth" were less saw-like than the horny
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
serrations on the beak of the fish-eating saw-billed ducks (Merginae
Merginae
The seaducks, Merginae, form a subfamily of the duck, goose and swan family of birds, Anatidae.As the name implies, most but not all, are essentially marine outside the breeding season. Many species have developed specialized salt glands to allow them to tolerate salt water, but these have not yet...
), pointing straight downwards instead and in the fossils often very abraded or broken. The downward-pointing "teeth" were ideal for digging into and holding slippery, soft-skinned pelagic animals such as cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s that were probably snatched out of the water in flight or while swimming. Lightly built as it was, O. orri was probably not a good diver and may have found it impossible to dive at all.
Osteodontornis is one of the pseudotooth birds of which rather comprehensive remains are known, but the lack of good fossils of most other Odontopterygiformes allows for few direct comparisons between genera. Still, the distal humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
of the present genus (e.g. the Barstovian
Barstovian
The Barstovian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 16,300,000 to 13,600,000 years BP, a period of . It is usually considered to overlap the Langhian and Serravallian...
specimen LACM 50660 from Kern County, California
Kern County, California
Spreading across the southern end of the California Central Valley, Kern County is the fifth-largest county by population in California. Its economy is heavily linked to agriculture and to petroleum extraction, and there is a strong aviation and space presence. Politically, it has generally...
) can be compared to that of a smaller and older fossil tentatively assigned to Odontopteryx
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....
. Osteodontornis has a wider and deeper notch between the external condyle and the ectepicondylar prominence, with the pit between these farther from the bone's end, than did the smallish 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...
species. Its quadrate bone
Quadrate bone
The quadrate bone is part of a skull in most tetrapods, including amphibians, sauropsids , and early synapsids. In these animals it connects to the quadratojugal and squamosal in the skull, and forms part of the jaw joint .- Evolutionary variation :In snakes, the quadrate bone has become elongated...
differed from that of Odontopteryx toliapica in a more narrowly grooved dorsal
Dorsum (biology)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
head, and a larger and less forward-pointing orbit
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...
al process. The forward center of the ventral articulation ridge extends upwards and forward, and the pterygoid process is conspicuously expanded to the upper center in Osteodontornis. The socket for the quadratojugal
Quadratojugal
The quadratojugal is a small jaw bone that is present in most amphibians, reptiles, and birds, but has been lost in mammals. It is connected to the jugal as well as other bones, though these may vary with species....
has an intermediate position and the lateral ridge of the slender main shaft is straight and fairly thin. The quadrate of the mysterious Pseudodontornis longirostris skull (which some consider to belong in 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....
) is not very well preserved; it agees with Odontopteryx in a broad main shaft and with Osteodontornis in the straight main shaft ridge and its upward-directed ventral articulation ridge's forward center. Otherwise, it differs from both.
Distribution
This 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...
is well documented from various locations of generally Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
age, although usually by much fragmented remains due to the thin and tender bones it had. Most importantly, it was found on both sides of the North Pacific. It is not certain whether all Osteodontornis remains belong to a single species; size differences suggest that some evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
took place during the timespan in which the genus
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...
existed. Thus, some fossils are referred to Osteodontornis only, without further assigning them to this species.
The type specimen of O. orri, SBMNH 309, is a rather comprehensive fossil preserved mostly as imprint, with some bone pieces and even feather impressions in addition; it was found in Clarendonian
Clarendonian
The Clarendonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 13,600,000 to 10,300,000 years BP, a period of . It is usually considered to overlap the Serravallian of the Middle...
(Late Miocene
Late Miocene
The Late Miocene is a sub-epoch of the Miocene Epoch made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch....
) shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
(USA). Subsequently, for example in the Barstovian
Barstovian
The Barstovian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 16,300,000 to 13,600,000 years BP, a period of . It is usually considered to overlap the Langhian and Serravallian...
(Middle Miocene
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene....
) Round Mountain Silt or in Late Miocene deposits of the Monterey Formation
Monterey Formation
The Monterey Formation is an extensive Miocene oil-rich geological sedimentary formation in California, with massive outcroppings of the formation in areas of the California Coast Ranges, Peninsular Ranges, and on some of California's off-shore islands...
, quite a few additional specimens dating from about the same time were found in California. Roughly contemporary specimens were described from the Haranoyan-Tozawan boundary in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
– a complete right quadrate bone
Quadrate bone
The quadrate bone is part of a skull in most tetrapods, including amphibians, sauropsids , and early synapsids. In these animals it connects to the quadratojugal and squamosal in the skull, and forms part of the jaw joint .- Evolutionary variation :In snakes, the quadrate bone has become elongated...
(NSM
National Science Museum of Japan
The is located in the northeast corner of Ueno park in Tokyo. Opened in 1871, the museum has had several names, including Ministry of Education Museum, Tokyo Museum, Tokyo Science Museum, the National Science Museum of Japan, and currently the National Museum of Nature and Science as of 2007...
PV-18696) from the Middle Miocene Nagura Formation
Nagura Formation
The Nagura Formation is a palaeontological formation located in Japan. It dates to the Middle Miocene period....
at Chichibu, Saitama
Chichibu, Saitama
is a city in Saitama, Japan. As of April 1, 2011, the city has an estimated population of 68,701, with a household number of 26,230. The total area is 577.69 km²....
, an Early Miocene
Early Miocene
The Early Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages....
right mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
piece (MFM 28351) found in the Oi Formation
Oi Formation
The Oi Formation is a palaeontological formation located in Japan. It dates to the Lower Miocene period....
at Misato, Mie
Misato, Mie
was a village located in Age District, Mie, Japan.On January 1, 2006 Misato, along with the towns of Anō, Geinō and Kawage, all from Age District, the towns of Hakusan, Ichishi and Karasu, the village of Misugi, all from Ichishi District, and the city of Hisai, was merged into the expanded city of...
, and some additional material of about the same age from the Mizunami Group at Mizunami, Gifu
Mizunami, Gifu
is a city located in the Tōnō region of Gifu, Japan.As of July 2011, the city has an estimated population of 40,030. The total area is 175.00 km².The city was founded on April 1, 1954....
. From the Early Miocene Nye Formation and the Middle Miocene
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene....
Astoria Formations 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...
a handful of specimens that appear to be Osteodontornis are known. Similar fossils have been found in the Middle Miocene Capadare Formation of Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
and from the Late Miocene of the Pisco Formation of Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
; they might rather be of a distinct but closely related genus, and it must be remembered that at that their time the Isthmus of Panama
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...
had not been formed yet so that an affiliation with the Atlantic 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....
cannot be discounted. The former, specimen MBLUZ-P-5093 from Cueva del Zumbador in Falcón State, is a premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
tip of immense dimensions; its bearer might have exceeded a wingspan of 7 metres (23 ft) in life. Though some of the Miocene North American material was initially (and sometimes is still) assigned to Pelagornis, recent authors generally place them in the present genus.
Some wing bone fossils from the Eo
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...
(USA), though assigned to Argillornis (= Dasornis
Dasornis
Dasornis is a 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....
), do not differ much from those of Osteodontornis (as far as can be told in their fragmented state), and may be from an older relative. They are the oldest known remains of large North Pacific pseudotooth birds, but if the enigmatic Cyphornis magnus from the same region dates back to the 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...
they may well be assignable to that taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
, whatever their systematic
Systematic
Systematic is an American hard rock band from Oakland, California. They were one of the first signings to Metallica drummer Lars Ulrich's record label, The Music Company, via Elektra Records. The band released two studio albums before disbanding in 2004....
affiliations might be beyond that. As few directly comparable bones of sufficient quality exist, the relationship of Osteodontornis to other pseudotooth birds is not completely resolved. As noted above, the entire genus (regardless of how many species can be recognized) may be a junior synonym of Cyphornis. Generally, recent authors have tended to place 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...
pseudotooth bird fossils from the Atlantic in Pelagornis, and those from the North Pacific in Osteodontornis. It remains to be seen if this east-west division can be upheld, but biogeographically it seems quite sensible at least as a working hypothesis
Working hypothesis
A working hypothesis is a hypothesis that is provisionally accepted as a basis for further research in the hope that a tenable theory will be produced, even if the hypothesis ultimately fails...
until sufficient well-preserved material has been found to make an in-depth study. It is less clear what to make of 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"...
pseudotooth birds fossils, none of which are complete enough for more than the most tentative identification. Many 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...
s of our time, such as albatross
Albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes . They range widely in the Southern Ocean and the North Pacific...
es and other Procellariiformes
Procellariiformes
Procellariiformes is an order of seabirds that comprises four families: the albatrosses, petrels and shearwaters, storm petrels, and diving petrels...
, show a phylogenetic division between Northern and Southern Hemisphere lineages, separated by the Equatorial current
Equatorial Current
Equatorial Current can refer to:*Equatorial Counter Current*North Equatorial Current*South Equatorial Current...
s. Whether this also held true in the warmer climate
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
of the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
is not known, but the general phylogenetic patterns found in Procellariiformes suggests that the north-south division is rather ancient and evolved even before the Miocene.
From the Neogene of 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...
"Pseudodontornis" stirtoni
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...
has been described, which unlike the rest of its (doubtfully valid) genus is not from the Paleogene Atlantic region. It has been proposed as 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 Neodontornis, but this has not been widely accepted. It may be valid still, as the bones are of a rather small pseudotooth bird; though apparently too small for Osteodontornis detailed comparisons could be insightful. Its 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 is indeed short and very 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...
, like in Osteodontornis but apparently unlike in the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of its supposed genus, P. longirostris. A larger proximal (initially misidentified as distal) humerus piece (CMNZ AV 24,960), probably from the Waiauan (Middle/Late Miocene) and found near the Waipara River
Waipara River
The Waipara River is a river the South Island of New Zealand.The river passes through the small town of Waipara on its 45 kilometre southeastward journey to the Pacific Ocean at the Northern end of Pegasus Bay....
mouth, is little if any distinct from O. orri in shape and size; it has a flange at the side and is less straight, but whether these features are natural or due to the damaged state of the specimens is unclear. It also agrees more with Pelagornis than with Paleogene remains from Oregon mentioned above. A distal left humerus end and some wing bone fragments from the Late Oligocene Yamaga Formation
Yamaga Formation
The Yamaga Formation is a palaeontological formation located in Japan. It dates to the Upper Oligocene period....
of Kitakyūshū (Japan) might be the oldest remains of an Osteodontornis, but their assignment to the present genus is just as uncertain as in the case of the New Zealand fossil. Also from Japan are one or two of the youngest pseudodontorn fossils – a fragmentary right humerus from the Early Pliocene Yushima Formation
Yushima Formation
The Yushima Formation, also known as the Tatsunokuchi Formation, is a palaeontological formation located in Japan. It dates to the Lower Pliocene period....
at Maesawa
Maesawa, Iwate
was a town located in Isawa District, Iwate, Japan.As of 2003, the town had an estimated population of 15,215 and a density of 210.33 persons per km²...
, and probably also a distal right femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
(MFM 1801) from the Early Pleistocene
Early Pleistocene
Calabrian is a subdivision of the Pleistocene Epoch of the Geologic time scale. ~1.8 Ma.—781,000 years ago ± 5,000 years, a period of ~.The end of the stage is defined by the last magnetic pole reversal and plunge in to an ice age and global drying possibly colder and drier than the late Miocene ...
Dainichi Formation
Dainichi Formation
The Dainichi Formation is a palaeontological formation located in Japan. It dates to the Upper Pliocene period....
at Kakegawa that was initially believed to be from an albatross. These might represent the last survivors of Osteodontornis – the Kakegawa fossil at least is a good match in size –, but require more study before they can be assigned there.
External links
- University of Kyoto: Photo of specimen MFM 28351. Retrieved 2009-AUG-20.
- FlickrFlickrFlickr is an image hosting and video hosting website, web services suite, and online community that was created by Ludicorp in 2004 and acquired by Yahoo! in 2005. In addition to being a popular website for users to share and embed personal photographs, the service is widely used by bloggers to...
: Photo of Round Mountain Silt jaw specimens at Buena Vista Museum of Natural History. Retrieved 2009-AUG-21. - FlickrFlickrFlickr is an image hosting and video hosting website, web services suite, and online community that was created by Ludicorp in 2004 and acquired by Yahoo! in 2005. In addition to being a popular website for users to share and embed personal photographs, the service is widely used by bloggers to...
: Photo of Astoria Formation arm specimen NMNH PAL 335794 and Nye Formation vertebrae specimen NMNH PAL 335621 at National Museum of Natural History (mislabeled as PelagornisPelagornisPelagornis 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....
). Retrieved 2009-AUG-21. - FlickrFlickrFlickr is an image hosting and video hosting website, web services suite, and online community that was created by Ludicorp in 2004 and acquired by Yahoo! in 2005. In addition to being a popular website for users to share and embed personal photographs, the service is widely used by bloggers to...
: Photo of holotype specimen (SBMNH 309) slab (with bone fragments) at Santa Barbara Museum of Natural History. Retrieved 2009-AUG-21. - FlickrFlickrFlickr is an image hosting and video hosting website, web services suite, and online community that was created by Ludicorp in 2004 and acquired by Yahoo! in 2005. In addition to being a popular website for users to share and embed personal photographs, the service is widely used by bloggers to...
: Photo of SBMNH 309 counterslab (with bone impressions) at Santa Barbara Museum of Natural History. Retrieved 2009-AUG-21. - FlickrFlickrFlickr is an image hosting and video hosting website, web services suite, and online community that was created by Ludicorp in 2004 and acquired by Yahoo! in 2005. In addition to being a popular website for users to share and embed personal photographs, the service is widely used by bloggers to...
: Another photo of SBMNH 309 counterslab at Santa Barbara Museum of Natural History. Retrieved 2009-AUG-21. - California Mediterranean Research Learning Center: Photo of a jaw specimen embedded in matrixMatrix (geology)The matrix or groundmass of rock is the finer grained mass of material in which larger grains, crystals or clasts are embedded.The matrix of an igneous rock consists of finer grained, often microscopic, crystals in which larger crystals are embedded. This porphyritic texture is indicative of...
. Retrieved 2009-AUG-21.