''Concavenator'' is an
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
theropod
Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
that lived approximately 130 million years ago during the early
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
period (
Barremian
The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is precede ...
age). The
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
is ''C. corcovatus''; ''Concavenator corcovatus'' means "
Cuenca hunter with a hump".
The fossil was discovered in the
Las Hoyas fossil site of
Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, i ...
by
paleontologists
Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...
José Luis Sanz, Francisco Ortega and Fernando Escaso from the
Autonomous University of Madrid
The Autonomous University of Madrid ( es, Universidad Autónoma de Madrid; UAM), commonly known as simply la Autónoma, is a Spanish public university located in Madrid, Spain. The university was founded in 1968 alongside the Autonomous Universi ...
and the
National University of Distance Education
The National Distance Education University, known in Spanish as ''Universidad Nacional de Educación a Distancia'' (UNED), is a public research university of national scope. The university was founded in 1972 under the Ministry of Universities. ...
.
Description
![Concavenator Scale](https://upload.wikimedia.org/wikipedia/commons/c/c9/Concavenator_Scale.svg)
''Concavenator'' was a medium-sized primitive
carcharodontosaurian
Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. Allosauroids, alongside the family Megalosauroidea, were among th ...
dinosaur, reaching in length and in body mass. It possessed several unique features, including the two extremely tall vertebrae in front of the hips which formed a tall but narrow and pointed crest (possibly supporting a hump) on the dinosaur's back.
The function of such crests is currently unknown. Paleontologist Roger Benson from the
University of Cambridge
, mottoeng = Literal: From here, light and sacred draughts.
Non literal: From this place, we gain enlightenment and precious knowledge.
, established =
, other_name = The Chancellor, Masters and Schola ...
speculated that one possibility is that "it is analogous to head-crests used in visual displays", but the Spanish scientists who discovered it noted it could also be a thermal regulator.
Integument
![Concavenator corcovatus](https://upload.wikimedia.org/wikipedia/commons/9/96/Concavenator_corcovatus.jpg)
''Concavenator'' had structures resembling quill knobs on its
ulna
The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...
, a feature known only in birds and other feathered theropods, such as ''
Velociraptor
''Velociraptor'' (; ) is a genus of small dromaeosaurid dinosaur that lived in Asia during the Late Cretaceous epoch, about 75 million to 71 million years ago. Two species are currently recognized, although others have been assigned in the pa ...
''. Quill knobs are created by ligaments which attach to the feather follicle, and since scales do not form from follicles, the authors ruled out the possibility that they could indicate the presence of long display scales on the arm. Instead, the knobs have been thought to probably anchor simple, hollow, quill-like structures. Such structures are known both in
coelurosaurs
Coelurosauria (; from Greek, meaning "hollow tailed lizards") is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs.
Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, tyran ...
such as ''
Dilong
''Dilong'' (; lit. "earth dragon") is a Chinese dragon name that is also used to mean "earthworm" in traditional Chinese medicine and '' Geosaurus'' in zoological nomenclature.
Dragon
In Chinese mythology, ''dilong'' "earth dragon" is one of ...
'' and in some
ornithischia
Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek s ...
ns like ''
Tianyulong
''Tianyulong'' (Chinese: 天宇龍; Pinyin: ''tiānyǔlóng''; named for the Shandong Tianyu Museum of Nature where the holotype fossil is housed) is an extinct genus of heterodontosaurid ornithischian dinosaur. The only species is ''T. confuc ...
'' and ''
Psittacosaurus
''Psittacosaurus'' ( ; "parrot lizard") is a genus of extinct ceratopsian dinosaur from the Early Cretaceous of what is now Asia, existing between 126 and 101 million years ago. It is notable for being the most species-rich non-avian dinosaur gen ...
''. If the ornithischian quills are homologous with bird feathers, their presence in an
allosauroid
Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. Allosauroids, alongside the family Megalosauroidea, were among ...
like ''Concavenator'' would be expected.
[ However, if ornithischian quills are not related to feathers, the presence of these structures in ''Concavenator'' would show that feathers had begun to appear in earlier, more primitive forms than coelurosaurs.
]
Feathers or related structures would then likely be present in the first members of the clade Neotetanurae
Avetheropoda, or "bird theropods", is a clade that includes carnosaurians and coelurosaurs to the exclusion of other dinosaurs.
Definition
Avetheropoda was named by Gregory S. Paul in 1988, and was first defined as a clade by Currie and Padia ...
, which lived in the Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...
. No impressions of any kind of integument were found near the arm, although extensive scale impressions were preserved on other portions of the body, including broad, rectangular scales on the underside of the tail, bird-like scutes on the feet, and plantar pads on the undersides of the feet.[
]
Some amount of skepticism has been raised among experts on the validity of the interpretation that the ulnar bumps represent quill knobs. Christian Foth and colleagues noted that the quill knobs of Concavenator were on the anterolateral side of the ulna, they suggest they were intermuscular lines that acted as tendon attachments
The hypothesis that the bumps along the ulna represented muscular insertion points or ridges was subsequently examined, and the results presented, at the 2015 meeting of the Society of Vertebrate Paleontology
The Society of Vertebrate Paleontology (SVP) is a professional organization that was founded in the United States in 1940 to advance the science of vertebrate paleontology around the world.
Mission and Activities
SVP has about 2,300 members inter ...
. Elena Cuesta Fidalgo, along with two of the researchers who initially described ''Concavenator'' (Ortega and Sanz), attempted to reconstruct its forearm musculature to determine if the ulnar bumps would be explained as an inter-muscular ridge. They identified the insertion point for the major arm muscles, and determined that the row of bumps could not have been located between any of them. They found that the only possibility was that the bumps could be an attachment scar for the ''M. anconeus'' muscle, which is unlikely, because this muscle normally attaches to a smooth surface without marks or bumps on the underlying bone, and argued that the most likely explanation for the bumps was their initial interpretation as feather quill knobs. The authors admitted that it was unusual for quill knobs to form along the posterolateral surface of the bone, but also noted that the same arrangement is found in some modern birds, like the Moorhen
Moorhens—sometimes called marsh hens—are medium-sized water birds that are members of the rail family (Rallidae). Most species are placed in the genus ''Gallinula'', Latin for "little hen".
They are close relatives of coots. They are of ...
.[Cuesta Fidalgo, Elena, Ortega, F., Sanz, J. (2015). Ulnar bumps of ''Concavenator'': Quill Knobs or Muscular scar? Myological Reconstruction of the forelimb of ''Concavenator corcovatus'' (Lower Cretaceous, Las Hoyas, Spain). ''Abstracts of papers of the 75th Annual Meeting of the Society of Vertebrate Paleontology'': 111-112.]
In 2018 Cuesta Fidalgo published her doctorate thesis on the anatomy of ''Concavenator'' which argued that the ulna was preserved in lateral view, meaning that the ulnar bumps were positioned posterolaterally rather than anterolaterally as Cau and Mortimer claimed. Cuesta Fidalgo noted that the proximal
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
part of the ulna is affected by fracturing and abrasion, and certain features would have shifted compared to their position in the bone when the animal was alive. For example, in the fossil, the lateral process of the ulna is positioned further posteriorly than the ulnar bumps. In ''Allosaurus'' and ''Acrocanthosaurus'', the lateral process is on the lateral (rather than posterior) part of the bone, which would seem to support the ulnar bumps being anterolateral in position if the lateral process was truly preserved in lateral orientation in ''Concavenator''. However, Cuesta Fidalgo described how the lateral process was distorted posteriorly compared to the bumps, and was not valid evidence for the claim that the ulna had shifted into anterior view. The ulna's distortion (as well as genus-specific proportions) means that precise comparisons to ''Allosaurus'' and ''Acrocanthosaurus'' would be misleading. As Cuesta Fidalgo and her colleagues explained in 2015, the ulnar bumps could not be an intermuscular line if the bone is preserved in lateral view. Cuesta Fidalgo and her colleagues, they pointed out that these bumps on the ulna are posterolateral which is unlike that of interosseous ligaments.
A book named "The Evolution of Feathers: From Their Origin to the Present" was published in 2020 to assess all the information about the evolution of feathers. In page 36 quill knobs Concavenator their significance remains controversial.
Classification
The following cladogram after Novas ''et al.'', 2013, shows its place within Carcharodontosauridae.
See also
* '' Altispinax''
* List of animals with humps
References
External links
''Concavenator'' arm bones, with quill knob-like structures visible
{{Taxonbar, from=Q131715
Carcharodontosaurids
Barremian life
Early Cretaceous dinosaurs of Europe
Cretaceous Spain
Fossils of Spain
La Huérguina Formation
Fossil taxa described in 2010