Compsognathus
Compognathus lived in the area of Europe, about 150 million years ago, during the Tithonian age of the late Jurassic Period. It can be assumed that they died out by the end of the Jurassic period. Compsognathus is a genus of theropod dinosaurs containing one single species, called Compsognathus longipes. The name of the genus means elegant or pretty jaw, and its specific name refers to its long legs.[1][2]
Compsognathus longipes. By Conty - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=5817214
Known occurrences of Compsognathus longipes fossils.
Discovery and fossil history
The first remains were found in the 1850s, in the lithographic limestone layers of Solnhofen, in the Riedenburg-Kelheim or the Jachenhausen area of Bavaria, Germany.[2] They could come from waste rock left over by quarrying. Its discoverer was a doctor and private collector, Joseph Oberndorfer, who later lent the almost complete skeleton to the paleontolgist Johann A. Wagner.[3] Since the collector wanted to keep the location of the fossil secret from rival collectors, neither the exact location nor the year of its discovery are known. However, all possible localities are part of lagoonal deposits of the Painten Formation, and date to the latest part of the late Kimmeridgian or the earlier part of the early Tithonian. [2] In 1866, Oberndorfer's collection, including the Compsognathus specimen, was acquired by the paleontological state collection in Munich.[4]
A larger specimen was discovered in the Portland Lithographic Limestone of Canjuers near Nice in France about 1971. It dates to the lower Tithonian, and it was part of the private collection of the owner of the quarries, Louis Ghirardi. From here it was transferred to the National Museum of Natural History in Paris in 1983.[5][6]
Fossil remains of Compsognathus longipes. By User:MatthiasKabel - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=2830300
Taxonomy and valid species
In 1859 Wagner described the species as a strange lizard.[7] Eight years later Thomas Huxley redescribed it as a dinosaur and compared it to the skeleton of Archeopteryx, which was considered the earliest known bird species, and found them similar to each other. Then he established that birds could have evolved from dinosaurs and this discovery elevated Compsognathus to the rank of the best-known dinosaur.[7][8]
Originally, in 1972 Alain Bidar and Gérard Thomel defined the French specimen as a new species, Compsognathus corallestris, because it was larger and had different forelimbs compared to the German specimen. In 1978 John Ostrom classified it again as a specimen of Compsognathus longipes. This is the first theropod known from a nearly complete skeleton. It was the smallest-known non-avian dinosaur until the 1990s.[5][6]
As for its taxonomic classification, in 1870, overriding previous classification schemes, Huxley proposed the new clade Ornithoscelida, which contained Dinosauria and another new clade, Compsognatha, which included Compsognathus.[9] In 1896 Othinel Charles Marsh erected the family Compsognathidae. Friedrich von Huene erected the new infraorder Coelurosauria in 1914, which includes the Compsognathidae. This classification has been in effect since then, and several related genera belonging to the Compsognatha clade have been discovered in recent decades, such as Aristosuchus.[5]
Mounted skeleton of Compsognathus longipes. By User:MatthiasKabel - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=2830301
Description and anatomy
The German specimen was estimated to be 70-90 cm long, 20 cm high at the hip and presumably weighed about 0.32-0.58 kilograms. Regarding the French specimen, it was around 1.25-1.4 m long with a height of 29 cm at the hip and might have weighed about 2.5-3.5 kilograms.[5][7][10] Bidar assumed webbed forelegs when describing the French specimen, therefore, some books depicted it as an amphibious dinosaur.[11] However, what were thought to be webbed remains were only sedimentary structures. It cannot be ruled out that it could swim.[5] This dinosaur ran on its long hind legs and its long tail helped it in balancing. Presumably it put its weight on its toes and not on its soles. On its more underdeveloped forelimbs it bore two large, clawed digits with which it grasped its prey. It had a third digit, which probably had no function. Its skull was narrow and elongated and its teeth were small and pointed. Hollow bones made it very agile. Its large eyes and long neck helped it to spot its prey as soon as possible.[5][12] Some believe that it wore feathers, but this is probably not true.[14][15]
Compsognathus longipes size comparison with human. By Dinosaur Zoo - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15875431
Paleobiology and paleoenvironment
The remains of a lizard were found in the chest cavity of the German specimen, which some thought was an embryo, but was actually a lizard. From this exploration we can conclude that Compsognathus fed on small vertebrates. [16][17] It had to be a fast and agile predator with sharp vision to catch lizards. Aggressive and temperamental behavior is associated with it. According to some laymen its bite was poisonous, but this has not been proven. Maybe it also ate insects. Based on a computer model, some researchers estimated its maximum speed of 17.8 meters per second. It appears to have swallowed the prey whole [7][18].
Near the German specimen, several egg-like remains can be seen, which were long interpreted as immature eggs. However, later researchers doubted this suggestion, as they were found outside the animal's body. A German geologist believed them to be gas bubbles that appeared during the rotting of the corpse. So currently, the scientific world does not have Compsognathus egg remains to reconstruct its nesting habits. In addition, it is also questionable whether they moved in herds, which can be assumed for a species of this size, but cannot be proven. Their form of communication is also a mystery. The paleontologists' theory is that from their size, a life span of 5-10 years can be inferred.[19][20]
During the Late Jurassic, Europe was a dry, tropical archipelago on the edge of the Tethys Sea. The skeleton of Compsognathus was found in fine limestone, which has been derived from calcite from the shells of marine organisms. The sites of the specimens were once lagoons located between the beaches and coral reefs of the Jurassic European islands of the Tethys Sea. The same sediments in which Compsognathus was found also contain fossils of marine animals, confirming a coastal habitat for this theropod. Some scientists believe they may have hunted in forested areas. No other dinosaur has been found in the company of Compsognathus, suggesting that these small dinosaurs may actually have been the largest land carnivores on these islands.[21][22]
Author: Csenge Lugosi, Biologist BSc student
Scientific references
[1] Liddell, Henry George; Scott, R. (1980) [1871]: A Greek-English Lexicon (abridged ed.). Oxford, United Kingdom: Oxford University Press. ISBN 978-0-19-910207-5.
[2] Reisdorf, A.G.; Wuttke, M. (2012): Re-evaluating Moodie's Opisthotonic-Posture Hypothesis in fossil vertebrates. Part I: Reptiles - The taphonomy of the bipedal dinosaurs Compsognathus longipes and Juravenator starki from the Solnhofen Archipelago (Jurassic, Germany). Palaeobiodiversity and Palaeoenvironments, 92 (1): 119-168. doi: 10.1007/s12549-011-0068-y.
[3] Wagner, J. A. (1859): Über einige im lithographischen Schiefer neu aufgefundene Schildkröten und Saurier. Gelehrte Anzeigen der Bayerischen Akademie der Wissenschaften, 49: 553.
[4] Göhlich, Ursula B.; Tischlinger, Helmut; Chiappe, Luis M. (2006): Juravenator starki (reptilia, theropoda), ein neuer Raubdinosaurier aus dem Oberjura der Südlichen Frankenalb (Süddeutschland). Archaeopteryx: Jahreszeitschrift der Freunde des Jura-Museums in Eichstätt. 24: 1-26.
[5] Peyer, Karin (2006): A reconsideration of Compsognathus from the upper Tithonian of Canjuers, southeastern France. Journal of Vertebrate Paleontology, 26 (4): 879-896. doi: 10.1671/0272-4634(2006)26[879:AROCFT]2.0.CO;2.
[6] Bidar, A.; Demay, L.; Thomel, G. (1972): Sur la présence du Dinosaurien Compsognathus dans le Portlandien de Canjures (Var). Comptes Rendus de l'Académie des Sciences, Série D. 275: 2327-2329.
[7] Ostrom, J.H. (1978): The osteology of Compsognathus longipes. Zitteliana, 4: 73-118.
[8] Huxley, Thomas Henry (1870): Further evidence of the affinity between the dinosaurian reptiles and birds. Quarterly Journal of the Geological Society, 26 (1-2): 12-31. doi: 10.1144/GSL.JGS.1870.026.01-02.08.
[9] Huxley, Thomas Henry (1870): On the classification of the Dinosauria, with observations on the Dinosauria of the Trias. Quarterly Journal of the Geological Society, 26 (1-2): 32-51. doi: 10.1144/GSL.JGS.1870.026.01-02.09.
[10] Paul, Gregory S. (1988): Early Avetheropods. Predatory Dinosaurs of the World. New York: Simon & Schuster. pp. 297-300. ISBN 978-0-671-61946-6.
[11] Bidar, A.; Demay L.; Thomel G. (1972): Compsognathus corallestris, une nouvelle espece de dinosaurien théropode du Portlandien de Canjuers (Sud-Est de la France). Annales du Muséum d'Histoire Naturelle de Nice, 1: 9-40.
[12] Gishlick, Alan D.; Gauthier, Jacques A. (2007): On the manual morphology of Compsognathus longipes and its bearing on the diagnosis of Compsognathidae. Zoological Journal of the Linnean Society, 149 (4): 569-581. doi: 10.1111/j.1096-3642.2007.00269.x.
[13] Lambert, David (1993): The Ultimate Dinosaur Book. New York: Dorling Kindersley. pp. 38-81. ISBN 978-1-56458-304-8
[14] Ji, S.; Ji, Q.; Lu, J.; Yuan, C. (2007): A new giant compsognathid dinosaur with long filamentous integuments from Lower Cretaceous of Northeastern China. Acta Geologica Sinica, 81 (1): 8-15.
[15] Peyer, K. (2006): A reconsideration of Compsognathus from the Upper Tithonian of Canjuers, southeastern France. Journal of Vertebrate Paleontology, 26 (4): 879-896. doi: 10.1671/0272-4634(2006)26[879:AROCFT]2.0.CO;2.
[16]Nopcsa, Baron F. (1903): Neues ueber Compsognathus. Neues Jahrbuch für Mineralogie, Geologie und Paläontologie, 16: 476-494.
[17] Evans, S.E. (1994): The Solnhofen (Jurassic: Tithonian) lizard genus Bavarisaurus: new skull material and a reinterpretation. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 192: 37-52.
[18] Sellers, William; Manning, Phillip (2007): Estimating maximum running speeds using evolutionary robotics. Proceedings. Biological Sciences. The Royal Society, 274 (1626): 2711-6. doi: 10.1098/rspb.2007.0846.
[19] Griffiths, P. (1993): The question of Compsognathus eggs. Revue de Paleobiologie Spec, 7: 85-94.
[20] Barthel, K.W. (1964): Zur Entstehung der Solnhofener Plattenkalke (unteres Untertithon). Mitteilungen der Bayerischen Staatssammlung für Paläontologie und historische Geologie, 4: 7-69.
[21] Weishampel, D.B.; Dodson, P.; Oslmolska, H. (2004): The Dinosauria (Second ed.). University of California Press
[22] Viohl G (1985): Geology of the Solnhofen lithographic limestone and the habitat of Archaeopteryx. In Hecht MK, Ostrom JH, Viohl G, Wellnhofer P (eds.). The Beginnings of Birds: Proceedings of the International Archaeopteryx Conference. Eichstätt: Freunde des Jura-Museums. pp. 31-44.