The Brachiosauridae ("arm lizards", from Greek ''brachion'' (βραχίων) = "arm" and ''sauros'' = "lizard") are a
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
or
clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
of
herbivorous, quadrupedal
sauropod
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
s.
Brachiosaurids had long necks that enabled them to access the leaves of tall trees that other
sauropods
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
would have been unable to reach.
In addition, they possessed thick spoon-shaped teeth which helped them to consume tough plants more efficiently than other sauropods.
They have also been characterized by a few unique traits or
synapomorphies; dorsal vertebrae with 'rod-like' transverse processes and an
with an abbreviated pubic peduncle.
''
Brachiosaurus
''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about . It was first Species description, described by American paleontologist Elmer S. Riggs in 1903 in paleontology, 1903 from fossi ...
'' is one of the best-known members of the Brachiosauridae, and was once thought to be the largest land animal to ever live.
Brachiosaurids thrived in the regions which are now
North
North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), direction or geography.
Etymology
T ...
and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
,
Africa
Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
,
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
, and
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
.
They first appear in the fossil record in the Late
Jurassic Period (possibly even earlier in the Middle Jurassic) and disappear in the late
Early Cretaceous Period.
The broad distribution of Brachiosauridae in both northern and southern continents suggests that the group originated prior to the breakup of
Pangaea.
In the Early Cretaceous the distribution of the group is dramatically reduced. It is still unclear whether this reduction is due to local extinctions or to the limited nature of the Early Cretaceous fossil record.
Brachiosauridae has been defined as all
titanosauriforms that are more closely related to ''Brachiosaurus'' than to ''
Saltasaurus''.
It is one of the three main groups of the clade
Titanosauriformes, which also includes the
Euhelopodidae and the
Titanosauria.
Description
The Brachiosauridae are composed of quadrupedal
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
s that are generally very large,
with the exception of the possible
insular dwarf ''
Europasaurus''. The brachiosaurids can be distinguished from other
macronarian
taxa
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
by their broad, thick and spoon-shaped teeth.
Their
maxilla
In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...
ry teeth were twisted apically, at the top, and the shape of these teeth was optimal for biting off resistant vegetation.
While brachiosaurids, like other sauropods, did not perform significant food processing in their mouths, their teeth enabled them to slice through food instead of having to pull it from tree branches.
Evidence for this precision shearing consists of apical wear facets on the teeth and distinctive bone structure that suggests orthal, vertical, jaw action.

In addition, the characteristic long necks of brachiosaurids are distinct from those of other long-necked dinosaur
taxa
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
.
They possessed a narrow neck composed of twelve to thirteen extremely long
cervical vertebrae
In tetrapods, cervical vertebrae (: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In saurop ...
that was laterally inflexible and dorsoventrally, vertically, flexible.
This meant that brachiosaurids could angle their necks up and lift their heads, enabling them to graze from treetops up to a height of about fourteen meters.
It has been argued that other
sauropods
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
lacked this dorsoventral flexibility and that their necks stretched outwards in front of them instead of upwards.
Brachiosaurids have more often been found in the conifer-rich sites, like the
Tendaguru, than in the
Morrison deposits, suggesting that their
fitness was increased by the presence of taller conifer food sources.
However, the giant size and long necks of brachiosaurids meant that they required tremendous pressure to bring oxygenated blood to their brains.
It has been proposed that sauropods possessed a four-chambered double pump heart, with one pump for oxygenated and one pump for deoxygenated blood.
As in all
Macronaria, the forelimbs of brachiosaurids are long relative to the hindlimbs, but this trait is more pronounced in brachiosaurids.
The forelimbs were very slender for a sauropod and the
metacarpal bones
In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular bones that form the intermediate part of the hand between the phalanges (fingers) and the carpal bones ( wrist bones), which articulate ...
of the forelimb were elongated.
These adaptations overall increased the stride length of the forelimbs, arguably resulting in an uneven gait.
However, it was previously argued that they were hindlimb dominant like other sauropods, and thus had the ability to rear up on their hindlimbs.
Based on the structure of their legs, making it impossible for them to run, it is likely that they moved about in a low walking speed (20–40 km/day), but were capable of moving faster when necessary, up to 20–30 km/hour, depending on leg length.
Brachiosaurids shared
synapomorphies, new traits typical for the group. They possessed middle and rear back
vertebra
Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...
e with long, 'rod-like' transverse processes. In the pelvis, the
had a shortened pubic peduncle, the contact surface with the
pubic bone.
Their
humeri, upper arm bones, had a large
deltopectoral crest. Their skull roofs showed wide supratemporal fenestrae, openings for the muscles.
They had
neural arches placed more on front of the vertebrae, shoulder blades that were expanded at the top end, irregularly shaped
coracoid
A coracoid is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is present as part of the scapula, but this is n ...
s in the shoulder girdle, and triangular projections on the underside of the front branch of their
quadratojugal bones at the lower rear corner of the skull.
History of findings
Changing classifications

In 1903,
Elmer Samuel Riggs described and named ''
Brachiosaurus
''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about . It was first Species description, described by American paleontologist Elmer S. Riggs in 1903 in paleontology, 1903 from fossi ...
''. In 1904, he created a new sauropod family, the Brachiosauridae.
[Riggs, E.S. 1904. "Structure and relationships of opisthocoelian dinosaurs. Part II, the Brachiosauridae". ''Field Columbian Museum, Geological Series 2'' 6: 229-247] He published a complete description of the
phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...
after examining the
humerus
The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...
,
femur
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg.
The Femo ...
,
coracoid
A coracoid is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is present as part of the scapula, but this is n ...
, and
sacrum of the ''Brachiosaurus''
holotype
A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
that had been prepared at the
Field Columbian Museum.
Since then, the classification of these sauropods has been through many changes.
Marsh's multifamily theory of sauropod classification prevailed until 1929, when
Werner Janensch proposed a two-family theory based on differences in sauropod teeth.
Macronarians with broad, spatulate teeth, were placed in the family Brachiosauridae, while sauropods with more slender and peg-shaped teeth were considered
titanosaurs.
This put
diplodocids and titanosaurids together in one group based on their similar teeth, despite the many other differences between the
taxa
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
.
Today, about four to five groups within the Macronaria are considered families (with names ending in ~).
In 1997, Salgado, Coria and Calvo studied the traits that had been used to set the Brachiosauridae apart and determined that they were in fact
plesiomorphic, original, for all basal
Titanosauriformes.
They proposed that some characteristics that had been used to differentiate ''Brachiosaurus'' were
synapomorphies for the Titanosauriformes as a whole.
They concluded that the family Brachiosauridae was actually a "grade" of not specially related primitive titanosauriforms, and not a stable separate
clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
.
They partly based this conclusion on similar humerus:femur length ratios known for titanosauriforms, basal titanosaurs, and more basal sauropods.
However, in 1998 Sereno & Wilson published data contrary to the conclusions in Salgado et al.'s article, indicating that the Brachiosauridae were a separate clade in the Titanosauriformes.
After 1998, new brachiosaurid species have been named, generally confirming that the Brachiosauridae were a natural group.
Important findings
In 1943, de Lapparent described the "French Bothriospondylus" from the Oxfordian of France which dates to the
Late Jurassic
The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...
, which was identified in 2013 by Philip Mannion as a brachiosaurid
and named ''
Vouivria damparisensis'' in 2017.
This specimen represents the oldest undisputed record of the brachiosaurid group.
The following diagram is a timeline of important brachiosaurid discoveries, the date given being that of the naming of the genus. The actual excavation was often much earlier, in the case of ''Vouivria'' eighty-three years and of ''
Duriatitan'' at least 136 years.
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id:white value:white
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id:2000s value:rgb(0.2,0.7,0.79)
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id:1900syears value:rgb(0.95,0.56,0.45)
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id:1700syears value:rgb(0.63,0.78,0.65)
id:latecretaceous value:rgb(0.74,0.82,0.37)
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from: 1824 till: 1830 color:1800syears text: 20s
from: 1830 till: 1840 color:1800syears text:30s
The prokaryotic small ribosomal subunit, or 30Svedberg, S subunit, is the smaller subunit of the 70S ribosome found in prokaryotes. It is a complex of the 16S ribosomal RNA (rRNA) and 19 proteins. This complex is implicated in the binding of tr ...
from: 1840 till: 1850 color:1800syears text: 40s
from: 1850 till: 1860 color:1800syears text: 50s
from: 1860 till: 1870 color:1800syears text: 60s
from: 1870 till: 1880 color:1800syears text: 70s
from: 1880 till: 1890 color:1800syears text: 80s
from: 1890 till: 1900 color:1800syears text: 90s
from: 1900 till: 1910 color:1900syears text: 00s
from: 1910 till: 1920 color:1900syears text: 10s
from: 1920 till: 1930 color:1900syears text: 20s
from: 1930 till: 1940 color:1900syears text:30s
The prokaryotic small ribosomal subunit, or 30Svedberg, S subunit, is the smaller subunit of the 70S ribosome found in prokaryotes. It is a complex of the 16S ribosomal RNA (rRNA) and 19 proteins. This complex is implicated in the binding of tr ...
from: 1940 till: 1950 color:1900syears text: 40s
from: 1950 till: 1960 color:1900syears text: 50s
from: 1960 till: 1970 color:1900syears text: 60s
from: 1970 till: 1980 color:1900syears text: 70s
from: 1980 till: 1990 color:1900syears text: 80s
from: 1990 till: 2000 color:1900syears text: 90s
from: 2000 till: 2010 color:2000syears text: 00s
from: 2010 till: 2020 color:2000syears text: 10s
from: 2020 till: 2030 color:2000syears text: 20s
from: 2030 till: 2040 color:2000syears text:30s
The prokaryotic small ribosomal subunit, or 30Svedberg, S subunit, is the smaller subunit of the 70S ribosome found in prokaryotes. It is a complex of the 16S ribosomal RNA (rRNA) and 19 proteins. This complex is implicated in the binding of tr ...
from: 2040 till: 2050 color:2000syears text: 40s
from: 2050 till: 2060 color:2000syears text: 50s
from: 2060 till: 2070 color:2000syears text: 60s
from: 2070 till: 2080 color:2000syears text: 70s
from: 2080 till: 2090 color:2000syears text: 80s
from: 2090 till: 2100 color:2000syears text: 90s
bar:eratop
from: 1824 till: 1900 color:1800s text: 19th
from: 1900 till: 2000 color:1900s text: 20th
from: 2000 till: 2100 color:2000s text: 21st
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color:1900s bar:NAM7 at:2006 mark:(line,black) text: Europasaurus
color:1900s bar:NAM1 at:1988 mark:(line,black) text:Giraffatitan
''Giraffatitan'' (name meaning "titanic giraffe") is a genus of sauropod dinosaur that lived during the late Jurassic Period (geology), Period (Kimmeridgian–Tithonian stages) in what is now Lindi Region, Tanzania. Only one species is known, ...
color:1900s bar:NAM1 at:1903 mark:(line,black) text: Brachiosaurus
color:1900s bar:NAM8 at:2010 mark:(line,black) text: Abydosaurus
color:1900s bar:NAM3 at:1999 mark:(line,black) text: Cedarosaurus
color:1800s bar:NAM4 at:2001 mark:(line,black) text: Venenosaurus
color:1900s bar:NAM5 at:2003 mark:(line,black) text: Lusotitan
color:1900s bar:NAM9 at:2010 mark:(line,black) text: Duriatitan
color:1800s bar:NAM6 at:2005 mark:(line,black) text: Daanosaurus
color:1800s bar:NAM2 at:1998 mark:(line,black) text: Sonorasaurus
color:1900s bar:NAM10 at:2017 mark:(line,black) text: Vouivria
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from: 1824 till: 1830 color:1800syears text: 20s
from: 1830 till: 1840 color:1800syears text:30s
The prokaryotic small ribosomal subunit, or 30Svedberg, S subunit, is the smaller subunit of the 70S ribosome found in prokaryotes. It is a complex of the 16S ribosomal RNA (rRNA) and 19 proteins. This complex is implicated in the binding of tr ...
from: 1840 till: 1850 color:1800syears text: 40s
from: 1850 till: 1860 color:1800syears text: 50s
from: 1860 till: 1870 color:1800syears text: 60s
from: 1870 till: 1880 color:1800syears text: 70s
from: 1880 till: 1890 color:1800syears text: 80s
from: 1890 till: 1900 color:1800syears text: 90s
from: 1900 till: 1910 color:1900syears text: 00s
from: 1910 till: 1920 color:1900syears text: 10s
from: 1920 till: 1930 color:1900syears text: 20s
from: 1930 till: 1940 color:1900syears text:30s
The prokaryotic small ribosomal subunit, or 30Svedberg, S subunit, is the smaller subunit of the 70S ribosome found in prokaryotes. It is a complex of the 16S ribosomal RNA (rRNA) and 19 proteins. This complex is implicated in the binding of tr ...
from: 1940 till: 1950 color:1900syears text: 40s
from: 1950 till: 1960 color:1900syears text: 50s
from: 1960 till: 1970 color:1900syears text: 60s
from: 1970 till: 1980 color:1900syears text: 70s
from: 1980 till: 1990 color:1900syears text: 80s
from: 1990 till: 2000 color:1900syears text: 90s
from: 2000 till: 2010 color:2000syears text: 00s
from: 2010 till: 2020 color:2000syears text: 10s
from: 2020 till: 2030 color:2000syears text: 20s
from: 2030 till: 2040 color:2000syears text:30s
The prokaryotic small ribosomal subunit, or 30Svedberg, S subunit, is the smaller subunit of the 70S ribosome found in prokaryotes. It is a complex of the 16S ribosomal RNA (rRNA) and 19 proteins. This complex is implicated in the binding of tr ...
from: 2040 till: 2050 color:2000syears text: 40s
from: 2050 till: 2060 color:2000syears text: 50s
from: 2060 till: 2070 color:2000syears text: 60s
from: 2070 till: 2080 color:2000syears text: 70s
from: 2080 till: 2090 color:2000syears text: 80s
from: 2090 till: 2100 color:2000syears text: 90s
bar:era
from: 1824 till: 1900 color:1800s text: 19th
from: 1900 till: 2000 color:1900s text: 20th
from: 2000 till: 2100 color:2000s text: 21st
Paleo biogeographic distribution

Definitive brachiosaurid remains have been found from the
Late Jurassic Period to the
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
, from about 157 to 100 million years ago.
In addition,
Macronaria in general first appear in the
Late Jurassic
The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...
. However, the almost simultaneous appearance of ''
Camarasaurus'', ''
Brachiosaurus
''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about . It was first Species description, described by American paleontologist Elmer S. Riggs in 1903 in paleontology, 1903 from fossi ...
'', and a possible
titanosaur suggest that they originated earlier, closer to the Mid-Jurassic.
Trackway evidence also supports a
Middle Jurassic
The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...
origin for titanosaurs, which implies the same for all
neosauropods.
Brachiosaurids in particular have a broad distribution dating to the
Late Jurassic
The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...
.
Late Jurassic
The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...
specimens have been discovered in the northern and southern Hemispheres, including
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
,
Africa
Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
,
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
, and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
.
This suggests that brachiosaurids originated in the
Middle Jurassic
The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...
, prior to the breakup of
Pangaea, followed by diversification and dispersal that resulted in the global spread present in the Late Jurassic.
This conclusion is further supported by
paleogeographic data.
While many Late Jurassic dinosaur remains have been found in
China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
, no brachiosaurid remains have been uncovered in East Asia.
This would support the Middle Jurassic origin theory since East Asia was separated from the rest of Pangaea by water from the late Middle Jurassic to the Early Cretaceous.
While brachiosaurids were widely dispersed in the Late Jurassic, their geographic distribution narrowed in the Early Cretaceous.
So far, brachiosaurid specimens have only been found in the Aptian-Albian region of North America.
This reduction in distribution occurs immediately following the Jurassic-Cretaceous boundary.
The brachiosaurid distribution in the Early Cretaceous has been interpreted as a result of regional extinctions in Europe, Africa, and South America.
Overall, the Early Cretaceous seems to be a time of reduced sauropod diversity worldwide. It has been argued that this change may be due to an extinction event at the Jurassic-Cretaceous boundary.
A second hypothesis is that the apparent lack of geographical diversity is due to sampling bias in the generally poor Early Cretaceous
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
record.
Recently discovered evidence supports the conclusion that brachiosaurids existed outside of North America in lower latitudes of
Gondwana
Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...
in the Early Cretaceous.
In 2013, Mannion et al. reported on the discovery of two isolated teeth found in
Lebanon
Lebanon, officially the Republic of Lebanon, is a country in the Levant region of West Asia. Situated at the crossroads of the Mediterranean Basin and the Arabian Peninsula, it is bordered by Syria to the north and east, Israel to the south ...
from the Early Cretaceous that possess posteriorly twisted crowns, which are characteristic of the brachiosaurids ''
Giraffatitan
''Giraffatitan'' (name meaning "titanic giraffe") is a genus of sauropod dinosaur that lived during the late Jurassic Period (geology), Period (Kimmeridgian–Tithonian stages) in what is now Lindi Region, Tanzania. Only one species is known, ...
'' and ''
Abydosaurus''.
In addition, a brachiosaurid named ''
Padillasaurus leivaensis'' was discovered in
Colombia
Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...
from the Early Cretaceous and placed in the Brachiosauridae
taxon
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
, which suggests that Brachiosauridae survived in northwestern Gondwana after the Jurassic/Cretaceous boundary.
In the Early Cretaceous, Colombia was located close to the equator in northwestern Gondwana while
Lebanon
Lebanon, officially the Republic of Lebanon, is a country in the Levant region of West Asia. Situated at the crossroads of the Mediterranean Basin and the Arabian Peninsula, it is bordered by Syria to the north and east, Israel to the south ...
was in the northeast of Gondwana.
This suggests that brachiosaurids were in fact present outside of North America in the Early Cretaceous, and supports the theory that the apparent lack of specimens is due to an incomplete record.
However, the rarity of these dinosaur specimens may also reflect a decrease in abundance of brachiosaurids acting in combination with the poor
fossil record
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
.
Also, in 2017 a study indicated that ''Padillasaurus'' was not a brachiosaurid but a basal member of the
Somphospondyli.
Classification
Brachiosauridae is one of the two major
clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
s of
Titanosauriformes, a diverse group of
sauropods
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
that existed in the
Late Jurassic
The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...
and
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
in
Laurasia
Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pa ...
and
Gondwana
Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...
. ''
Europasaurus'' is considered the most basal brachiosaurid.
Titanosauriformes was a globally distributed, long-lived
clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
of
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
s that contained both the largest and smallest known
sauropods
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
.
This
clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
was composed of three distinct groups: Brachiosauridae, a mix of
Late Jurassic
The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...
and
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
sauropods
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
,
Euhelopodidae, a group of mid-
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
East Asian
sauropods
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
, and
Titanosauria, a large
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
located mostly in
Gondwana
Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...
.
Traditionally, Brachiosauridae included ''
Brachiosaurus
''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about . It was first Species description, described by American paleontologist Elmer S. Riggs in 1903 in paleontology, 1903 from fossi ...
'' and some other suggestively assigned genera. Following the generic separation of ''Brachiosaurus'' species into ''B. altithorax'' and ''
Giraffatitan brancai'' these have sometimes been the only members supported by
cladistic
Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...
analysis.
Cladogram of Brachiosauridae after D'Emic ''et al.'' (2016).
Cladogram of Brachiosauridae after Mannion ''et al.'' (2017).
References
External links
Artist's rendering of fourteen brachiosaursBrachiosauridae
{{Taxonbar, from=Q131146
Dinosaur families