Compsognathidae is a family of
coelurosauria
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, t ...
n
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 ...
dinosaurs
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 ...
. Compsognathids were small
carnivore
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...
s, generally conservative in form, hailing from the
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
and
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 ...
Periods. The bird-like features of these species, along with other dinosaurs such as ''
Archaeopteryx
''Archaeopteryx'' (; ), sometimes referred to by its German name, "" ( ''Primeval Bird''), is a genus of bird-like dinosaurs. The name derives from the ancient Greek (''archaīos''), meaning "ancient", and (''ptéryx''), meaning "feather" ...
'' inspired the idea for the connection between dinosaur reptiles and modern-day avian species. Compsognathid fossils preserve diverse integument — skin impressions are known from four genera commonly placed in the group, ''
Compsognathus
''Compsognathus'' (; Ancient Greek, Greek ''kompsos''/κομψός; "elegant", "refined" or "dainty", and ''gnathos''/γνάθος; "jaw") is a genus of small, bipedalism, bipedal, carnivore, carnivorous theropoda, theropod dinosaur. Members o ...
'', ''
Sinosauropteryx
''Sinosauropteryx'' (meaning "Chinese reptilian wing", ) is a compsognathid dinosaur. Described in 1996, it was the first dinosaur taxon outside of Avialae (birds and their immediate relatives) to be found with evidence of feathers. It was cover ...
'', ''
Sinocalliopteryx
''Sinocalliopteryx'' (meaning 'Chinese beautiful feather') is a genus of carnivorous compsognathid theropod dinosaurs from the Lower Cretaceous Yixian Formation of China (Jianshangou Beds, dating to 124.6 Ma).
While similar to the related ''Huax ...
'', and ''
Juravenator
''Juravenator'' is a genus of small (75 cm long) coelurosaurian theropod dinosaur (although a 2020 study proposed it to be a hatchling megalosauroid), which lived in the area which would someday become the top of the Franconian Jura of Ger ...
''.
[Xu, Xing. "Palaeontology: Scales, feathers and dinosaurs." ''Nature'' 440.7082 (2006): 287-288.] While the latter three show evidence of a covering of some of the earliest primitive feathers over much of the body, ''Juravenator'' and ''Compsognathus'' also show evidence of scales on the tail or hind legs. ''
Ubirajara'', described in 2020, had elaborate integumentary structures on its back and shoulders superficially similar to the display feathers of a
standardwing bird-of-paradise, and unlike any other non-avian dinosaur currently described.
The first member of the group, ''
Compsognathus
''Compsognathus'' (; Ancient Greek, Greek ''kompsos''/κομψός; "elegant", "refined" or "dainty", and ''gnathos''/γνάθος; "jaw") is a genus of small, bipedalism, bipedal, carnivore, carnivorous theropoda, theropod dinosaur. Members o ...
'', was discovered in 1861, after Johann A. Wagner published his description of the taxon.
[Peyer, Karin. "A reconsideration of Compsognathus from the Upper Tithonian of Canjuers, southeastern France." ''Journal of vertebrate Paleontology'' 26.4 (2006): 879-896.][Sales, Marcos AF, Paulo Cascon, and Cesar L. Schultz. "Note on the paleobiogeography of Compsognathidae (Dinosauria: Theropoda) and its paleoecological implications." ''Anais da Academia Brasileira de Ciências'' 86.1 (2014): 127-134.][Wagner, A. "Neue Beiträge zur Kenntnis der urweltlichen Fauna des lithographischen Schiefers; V. Compsognathus longipes Wagner." ''Abhandlungen der Bayerischen Akademie der Wissenschaften'' 9 (1861): 30-38.] The family was created by
Edward Drinker Cope
Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested ...
in 1875.
[Naish, Darren, David M. Martill, and Eberhard Frey. "Ecology, systematics and biogeographical relationships of dinosaurs, including a new theropod, from the Santana Formation (? Albian, Early Cretaceous) of Brazil." ''Historical Biology'' 16.2-4 (2004): 57-70.] This classification was accepted by
Othniel Charles Marsh
Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among h ...
in 1882, and added to the Coelurosauria clade by
Friedrich von Huene in 1914 after additional fossils had been found.
With further discoveries, fossils have been uncovered across three different continents, in Asia,
Europe, and South America.
Assignment to Compsognathidae is usually determined through examination of the
metacarpal
In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...
, which is used to separate Compsognathidae from other dinosaurs.
[Gishlick, Alan D., and Jacques A. Gauthier. "On the manual morphology of Compsognathus longipes and its bearing on the diagnosis of Compsognathidae." ''Zoological Journal of the Linnean Society'' 149.4 (2007): 569-581.] However, classification is still complicated due to similarities to the body of several other theropod dinosaurs, as well as the lack of unifying, diagnostic features that are shared by all compsognathids.
It has been proposed that at least some compsognathids represent juvenile specimens of larger
tetanuran
Tetanurae (/ˌtɛtəˈnjuːriː/ or "stiff tails") is a clade that includes most theropod dinosaurs, including megalosauroids, allosauroids, tyrannosauroids, ornithomimosaurs, compsognathids and maniraptorans (including birds). Tetanurans ar ...
theropods, such as
carnosaurs
Carnosauria is an extinct large group of predatory dinosaurs that lived during the Jurassic and Cretaceous periods. Starting from the 1990s, scientists have discovered some very large carnosaurs in the carcharodontosaurid family, such as ''Gi ...
.
History of Discovery
![Compsognathus longipes cast 3](https://upload.wikimedia.org/wikipedia/commons/c/c9/Compsognathus_longipes_cast_3.jpg)
The first significant fossil specimen of Compsognathidae was found in the Bavaria region of Germany (BSP AS I 563) and given to collector Joseph Oberndorfer in 1859. The finding was initially significant because of the small size of the specimen. In 1861, after an initial period of review, Johann A. Wagner presented his analysis of the specimen to the public and named the fossil ''
Compsognathus longipes'' ("elegant jaw"). In 1868,
Thomas Henry Huxley
Thomas Henry Huxley (4 May 1825 – 29 June 1895) was an English biologist and anthropologist specialising in comparative anatomy. He has become known as "Darwin's Bulldog" for his advocacy of Charles Darwin's theory of evolution.
The storie ...
, an early supporter of
Charles Darwin
Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...
and his
theory of evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variatio ...
, used ''Compsognathus'' in a comparison to similar feathered dinosaur ''
Archaeopteryx
''Archaeopteryx'' (; ), sometimes referred to by its German name, "" ( ''Primeval Bird''), is a genus of bird-like dinosaurs. The name derives from the ancient Greek (''archaīos''), meaning "ancient", and (''ptéryx''), meaning "feather" ...
'' in order to propose the origin of
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s. Huxley noticed that these dinosaurs shared a similar layout to birds and proposed an exploration of the similarities. He is credited as being the first person to do so. This initial comparison sparked the interest into the origin of birds and feathers. In 1882,
Othniel Charles Marsh
Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among h ...
named a new family of dinosaurs for this species ''Compsognathidae'' and officially recognized the species as part of Dinosauria''.''
[Ostrom, J. H. (1978). ''The osteology of Compsognathus longipes Wagner''. Zitteliana.]
Notable Specimens
![Juravenator Scale](https://upload.wikimedia.org/wikipedia/commons/1/14/Juravenator_Scale.svg)
In 1971, a second nearly complete specimen of ''Composgnathus longipes'' was found in the area of Canjuers, which is located in the southeast of France near Nice.
This specimen was much larger than the original German specimen, but similarities led to experts categorizing the fossil as an adult ''Compsognathus longipes'' and leading to the further classification of the German specimen as a juvenile. This specimen also contained a lizard in the digestive region, further solidifying the theory that compsognothids consumed small vertebrate species.
The holotype of ''
Juravenator
''Juravenator'' is a genus of small (75 cm long) coelurosaurian theropod dinosaur (although a 2020 study proposed it to be a hatchling megalosauroid), which lived in the area which would someday become the top of the Franconian Jura of Ger ...
'' is the only known specimen of the species. Though ''Juravenator'' has previously been accepted as a member of Compsognathidae, recent research has led some experts to believe that ''Juravenator'' does not belong in this group. This is due to the fact that ''Juravenator'' could also be classified into a similar group within Coelurosauria,
Maniraptoriformes
Maniraptoriformes is a clade of dinosaurs with pennaceous feathers and wings that contains ornithomimosaurs and maniraptorans. This group was named by Thomas Holtz, who defined it as "the most recent common ancestor of '' Ornithomimus'' and bird ...
. Maniraptoriforms share many similarities with compsognathids and due to the fact that there has been only one verified specimen of ''Juravenator,'' experts have disagreed on exactly where to place this genus. Since 2013, ''Juravenator'' is still commonly classified as a coelurosaur, but near the group Maniraptoriformes instead of Compsognathidae.
[Godefroit, Pascal; Cau, Andrea; Hu, Dong-Yu; Escuillié, François; Wu, Wenhao; Dyke, Gareth (2013). "A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds". ''Nature''. 498 (7454): 359–362. . . ]
A compsognathid specimen consisting of a single finger bone has been described from Late Jurassic (
Tithonian
In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the K ...
Age, about 150 million years ago) sediments at Port Waikato, New Zealand. It is the first and so far, only dinosaur specimen known from Jurassic New Zealand, as well as being the first New Zealand dinosaur fossil to have been found outside of the Cretaceous marine sediments at Mangahouanga Stream. Possible coprolites have been referred to this specimen, however it is still not an officially classified species.
Description
Compsognathids share a variety of characteristics. The genera in this family demonstrate traits that are characteristic of
theropods
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 ca ...
, such as smaller forelimbs than hind legs. Size, feathers, and metacarpal size are among the most important classifying common characteristics.
Size
![Compysizes1](https://upload.wikimedia.org/wikipedia/commons/e/e8/Compysizes1.png)
Compsognathids are considered to be among the smallest dinosaurs ever discovered. ''Compsognathus longipes'' was formerly the smallest known dinosaur. It was around the size of a chicken when fully grown: around long and weighing . However, recently discovered adult specimens of other dinosaurs are smaller than ''Compsognathus'', including ''
Caenagnathasia
''Caenagnathasia'' ('recent jaw from Asia') is a small caenagnathid oviraptorosaurian theropod from the Late Cretaceous of Uzbekistan.
Discovery
The type species ''Caenagnathasia martinsoni'' was named and described in 1994 by Philip J. Currie ...
'', ''
Microraptor
''Microraptor'' (Greek, μικρός, ''mīkros'': "small"; Latin, ''raptor'': "one who seizes") is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China. They ...
'', and ''
Parvicursor
''Parvicursor'' (meaning "small runner") is a genus of tiny maniraptoran dinosaur with long slender legs for fast running. At only about from snout to end of tail, and in weight, it was initially seen as one of the smallest non-avian dinosau ...
'', all of which are estimated to be less than 1 m long. However, most of these specimens are incomplete, so these sizes remain estimates.
The other genera in this family are slightly larger than ''Compsognathus longipes'', but generally similar in size. The largest compsognathid is ''Huaxiagnathus'', which is estimated from its holotype to be around long,
[Hwang SH, Norell MA, Ji Q, Gao K-Q (2004) A large compsognathid from the Early Cretaceous Yixian Formation of China. J Syst Pal 2: 13–30. .] while ''Sinocalliopteryx'' measures around long. ''Sinosauropteryx'' is the most similar to ''Compsognathus'', measuring at most long.
[Switek, Brian (August 31, 2012).]
Stomach Contents Preserve Sinocalliopteryx Snacks
Feathers
![Sinosauropteryx color](https://upload.wikimedia.org/wikipedia/commons/c/ce/Sinosauropteryx_color.jpg)
The phylogeny of Compsognathidae organizes this family near the
development of feathers in dinosaurs. In 1998, evidence of filamentous protofeathers was presented in a study on ''Sinosauropteryx'', marking the first time that any sort of feather structure was found outside of birds and their related species. After this, more evidence of feather structure was found in other genera of Compsognathidae. Evidence of protofeathers bearing resemblance to ''Sinosauropteryx'' was found on ''Sinocalliopteryx'' specimens, including on the foot of the specimen. There have been signs of basic feather structures on ''Juravenator'', but evidence of this is still not definite. Samples of ''Juravenator'' skin show scales instead of feathers, leading into debates about ''Juravenator''’s place within the family Compsognathidae. However, a 2010 examination of ''Juravenator'' under UV light showed filaments similar to those seen on other compsognathid specimens, indicating that it is likely that these dinosaurs had some sort of feathering. A 2020 study concluded the "scales" were actually
adipocere, though the same study defended ''Juravenator'' was a
megalosauroid
Megalosauroidea (meaning 'great/big lizard forms') is a Taxonomic rank, superfamily (or clade) of Tetanurae, tetanuran theropod dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period. The group is defined as ''Megalosaurus, M ...
and not a compsognathid.
Metacarpals
Another way of classification of Compsognathidae is shared
metacarpal
In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
* Morphology (archaeology), study of the shapes or forms of artifacts
* Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
. A 2007 study found similarities between compsognathid genera in certain metacarpal I morphologies. The conclusion of this study found that Composgnathidae had a distinct manual morphology where, like theropods, the first digit of the manus is larger than the other digits, but with a distinct metacarpal I morphology where the metacarpal is stocky and short. Compsognathidae also has a projection from the manus that is on this metacarpal.
Classification
The Compsognathidae are a group of mostly small dinosaurs from the late Jurassic and 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 ...
periods of China, Europe and South America.
For many years, ''
Compsognathus
''Compsognathus'' (; Ancient Greek, Greek ''kompsos''/κομψός; "elegant", "refined" or "dainty", and ''gnathos''/γνάθος; "jaw") is a genus of small, bipedalism, bipedal, carnivore, carnivorous theropoda, theropod dinosaur. Members o ...
'' was the only member known, but in recent decades paleontologists have discovered several related genera. The
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
includes ''
Aristosuchus
''Aristosuchus'' is a genus of small coelurosaurian dinosaur whose name was derived from the Ancient Greek, Greek ἄριστος (meaning bravest, best, noblest) and ''σουχος'' (the Ancient Greek corruption of the name of the Ancient Egypt ...
'', ''
Huaxiagnathus'', ''
Mirischia
''Mirischia'' is a small (two meter-long) genus of compsognathid theropod dinosaur from the Albian stage ( Early Cretaceous Period) of Brazil.
Discovery and naming
In 2000 David Martill and Eberhard Frey reported the find of a small dinosaur ...
'', ''
Sinosauropteryx
''Sinosauropteryx'' (meaning "Chinese reptilian wing", ) is a compsognathid dinosaur. Described in 1996, it was the first dinosaur taxon outside of Avialae (birds and their immediate relatives) to be found with evidence of feathers. It was cover ...
'',
and perhaps ''
Juravenator
''Juravenator'' is a genus of small (75 cm long) coelurosaurian theropod dinosaur (although a 2020 study proposed it to be a hatchling megalosauroid), which lived in the area which would someday become the top of the Franconian Jura of Ger ...
'' and ''
Scipionyx
''Scipionyx'' ( ) was a genus of theropod dinosaur from the Early Cretaceous of Italy, around 113 million years ago.
There is only one fossil known of ''Scipionyx'', discovered in 1981 by an amateur paleontologist and brought to the attention o ...
''. At one time, ''
Mononykus
''Mononykus'' ( , sometimes ; meaning "one claw") is a genus of alvarezsaurid dinosaur that lived during the Late Cretaceous in what is now Asia on the Nemegt Formation, about 70 million years ago.
''Mononykus'' was a very small theropod, estim ...
'' was proposed as a member of the family, but this was rejected by Chen and coauthors in a 1998 paper; they considered the similarities between ''Mononykus'' and the compsognathids to be an example of
convergent evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
.
The position of Compsognathidae within the
coelurosaur
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 ...
group is uncertain. Some, such as theropod expert
Thomas Holtz Jr. and co-authors
Ralph Molnar
Ralph E. Molnar is a paleontologist who had been Curator of Mammals at the Queensland Museum and more recently associated with the Museum of Northern Arizona. He is also a research associate at the Texas natural Science Centre. He co-authored descr ...
and
Phil Currie
Philip John Currie (born March 13, 1949) is a Canadian palaeontologist and museum curator who helped found the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta and is now a professor at the University of Alberta in Edmonton. In the ...
in the landmark 2004 text ''Dinosauria'', hold the family as the most
basal of the coelurosaurs,
while others as part of the
Maniraptora
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to ''Ornithomimus velox''. It contains the major subgroups Avialae, Deinonychosauria, Oviraptoros ...
.
Below is a simplified cladogram showing Compsognathidae by Senter ''et al.'' in 2012.
Palaeobiology
Diet
Compsognathids were carnivores and certain specimens have contained the remains of their diet. The German specimen of Compsognathus included remains in the digestive region, which was initially thought to be an unborn embryo. However, further analysis found that the remains belong to a lizard with an elongated tail and stretched legs.
[Nopcsa, Baron F. (1903). "Neues ueber ''Compsognathus''". ''Neues Jahrbuch fur Mineralogie, Geologie und Palaeontologie (Stuttgart)''. 16: 476–494.] Other compsognathids, such as ''Sinosauropteryx,'' have been shown to eat lizards.
References
{{Taxonbar, from=Q134196
Compsognathids
Prehistoric dinosaur families
Tithonian first appearances
Early Cretaceous extinctions