| Procompsognathus | |
|---|---|
 | |
| Holotype specimen (SMNS 12591) | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Family: | †Coelophysidae |
| Genus: | †Procompsognathus Fraas, 1913 |
| Species: | †P. triassicus |
| Binomial name | |
| †Procompsognathus triassicus Fraas, 1913 | |
Procompsognathus/ˌproʊkɒmpˈsɒɡnəθəs/ is anextinctgenus ofcoelophysidtheropoddinosaur that lived approximately 210million years ago during the later part of theTriassicPeriod, in what is nowGermany.Procompsognathus was a small-sized, lightly built, ground-dwelling,bipedalcarnivore, that could grow up to 1 m (3.3 ft) long.
The fragmentary and poorly preserved skeleton ofProcompsognathus was found in the MiddleStubensandstein member of theLöwenstein Formation at theWeiße Steinbruch, the quarry of Albert Burrer on the northern slopes of theStromberg region nearPfaffenhofen inWürttemberg,Germany.[1][2] The discovery was made by Albert Burrer in the spring of 1909 in white sandstone and gray/blue marl sediments that were deposited during theNorianstage of theTriassic period.[2]
TheholotypeSMNS 12591, consisted of three blocks of sandstone: one showed a small, seven-centimetre-long, severely crushed skull with lower jaws. The second and third contained the partly articulated remains of a postcranial skeleton, including twenty-nine vertebrae of the neck, back and tail; ribs; elements of the shoulder girdle and a forelimb; an ilium; both pubis and the hindlimbs. It represents an adult individual.[2]
Burrer sent the specimen to ProfessorEberhard Fraas of thekönigliche Stuttgarter Naturalienkabinett. In a lecture on 9 October 1911, Fraas referred to it by the name "Hallopus celerrimus", considering it a jumping form of dinosaur that was approximately 60 cm (2.0 ft) long, and was associated with theorigin of birds.[3] Later, Fraas decided to use a different name in the official publication.[4] Fraas in 1913 named the genusProcompsognathus with astype species,Procompsognathus triassicus.[5] The type specimen is housed in the collection of theState Museum of Natural History inStuttgart, Germany.[2]
In 1921,Friedrich von Huene referred two more specimens, both also found in the Burrer quarry, in 1908, toProcompsognathus: SMNS 12352, a partial skull and lower jaws from a larger individual than the holotype, and SMNS 12352a, an isolated left hand.[6]
The genus nameProcompsognathus, means "before elegant jaw", and is derived from the name of another dinosaur,Compsognathus. A later (Jurassic) smallpredatory dinosaur,Compsognathus takes its name from theGreek wordkompsos (κομψός) which can be rendered as "elegant", "refined" or "dainty" and theGreek wordgnathos (γνάθος) which means "jaw". The prefixPro (προ) implies "before" or "ancestor of", although this direct lineage was not supported by subsequent research. Thespecific nametriassicus refers to the geologic time period to which this dinosaur belongs, the Triassic.[7]
Procompsognathus may have been about 1 metre (3.3 ft) long,[8] though Fraas in 1913 estimated a length of 75 cm (2.5 ft). In 2010Gregory S. Paul gave an estimate of 1 kilogram (2.2 lb) for the weight with a length of 1.1 metres (3.6 ft).[9] In 2016, the holotype gained estimates of 1.3 kg and 28 cm in height at the hips.[10] Abiped,Procompsognathus had long hind legs, short arms, large clawed hands, a long slender snout with many small teeth, and a stiff tail. The femur discovered for the type specimen of this genus measures 93mm and the tibia, 112mm. The tibia is approximately 20% longer than the femur inProcompsognathus, an adaptation which has been strongly correlated with the development ofcursorial habits in dinosaurs, suggesting that they were good runners.[11]
While it is undoubtedly a small, bipedal carnivore, the extremely poor preservation of the only knownProcompsognathus fossil makes its exact identity difficult to determine. Fraas originally assigned it to the Dinosauria. In 1923Franz Nopcsa coined a Procompsognathinae, and in 1929 von Huene created a Procompsognathidae, though these concepts are today rarely used. In 1932 von Huene saw it as a member of the non-dinosaurianPseudosuchia.[12] It has since then usually been considered a theropod dinosaur, with some exceptions. In 1992Paul Sereno andRupert Wild stated that theholotype specimen consisted of fossils from two separate animals: the postcranial skeleton would be a theropod, likely acoelophysoid related toSegisaurus, but the skull and the von Huene specimens they referred to the basalcrocodylomorphSaltoposuchus connectens.[13] However, in 1993Sankar Chatterjee after further preparation refuted their assessment and regarded the skull as that of a theropod similar toMegapnosaurus, and demonstrated that it could not have been a crocodylomorph, as it lacks the landmark features of this group.[14][15] Sereno (1997) and Ezcurra and Novas (2007) conducted phylogenetic analysis that supported the placement ofProcompsognathus in the taxonCoelophysidae.[16][17] This genus may be most closely related toSegisaurus halli.[18]
Much controversy has arisen however, about the association with the later material referred by von Huene. In 1982John Ostrom claimed that SMNS 12352 and SMNS 12352a originated from a taxon different from the holotype. In 2006 and 2008Fabien Knoll concluded that SMNS 12352 represented a crocodylomorph and SMNS 12352a a crocodylomorph or some other basalarchosaur. The postcranial skeleton, for which he reserved the inventory number SMNS 12591, was a coelophysoid; and the skull, now indicated with the number SMNS 12591a, a perhaps more derived theropod, possibly a basal member of theTetanurae.[19][2] In 2012 Knoll after aCAT-scan reaffirmed that SMNS 12352 was a crocodylomorph, but established it was different fromSaltoposuchus.[20]
Oliver Rauhut and Axel Hungerbuhler (2000) noted features of thevertebrae which suggest thatProcompsognathus may be acoelophysid orceratosaur,[21] and Carranoet al. (2005), in their re-study of the related genusSegisaurus, found bothSegisaurus andProcompsognathus to belong to the Coelophysidae within Dinosauria.[22] In 2004 David Allen consideredProcompsognathus to be a primitive, non-dinosaurianornithodiran.[23]
Procompsognathus lived in a relatively dry, inland environment and may have eateninsects,lizards and other small prey.[24] Contemporaries ofProcompsognathus included thecoelophysoidsHalticosaurus andDolichosuchus, as well as theSauropodomorphsPlateosaurus gracilis andEfraasia minor. Weishampel,et al. (2004) noted that theropod tracks and fossils of an unnamed herrerasaur genus are known from the Lower Stubensandstein.[25]
Procompsognathus appears in the novelJurassic Park and its sequelThe Lost World byMichael Crichton. Individuals of the species are sometimes referred to as "compys" by the characters. While the author invents avenomous bite forProcompsognathus withsoporific effects, there is no evidence to support venom inProcompsognathus.[26]
.jpg)
.jpg)
.png)
.jpg)
