Dryptosaurus

Dryptosaurus Temporal range: Late Cretaceous, 67 Ma PreЄ Є O S D C P T J K Pg N ↓
Elements of the type specimen
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Order:	Saurischia
Suborder:	Theropoda
Superfamily:	†Tyrannosauroidea
Family:	†Dryptosauridae Marsh, 1890
Genus:	†Dryptosaurus Marsh, 1877
Species:	†D. aquilunguis
Binomial name
Dryptosaurus aquilunguis (Cope, 1866 [originally Laelaps])
Synonyms
Laelaps aquilunguis Cope, 1866 (preoccupied) Megalosaurus aquilunguis (Cope, 1866)

Laelaps aquilunguis Cope, 1866 (preoccupied)
Megalosaurus aquilunguis (Cope, 1866)

Dryptosaurus (pron.:"DRIP-toe-SORE-us") is a genus of primitive tyrannosauroid that lived approximately 67 million years ago during the latter part of the Cretaceous period in what is now Eastern North America. Dryptosaurus was a large, bipedal, ground-dwelling carnivore, that could grow up to 7.5 m (24.6 ft) long. Although largely unknown now outside of academic circles, a famous painting of the genus by Charles R. Knight made it one of the more widely known dinosaurs of its time, in spite of its poor fossil record. First described by Edward Drinker Cope in 1866 and later renamed by Othniel C. Marsh in 1877, Dryptosaurus is among the first theropod dinosaurs known to science.

Dryptosaurus is estimated to have been 7.5 metres (24.6 ft) long and to have weighed 1.5 metric tons (1.7 short tons), although this is based on partial remains of one individual. Like its relative Eotyrannus, Dryptosaurus seems to have had relatively long arms when compared with more derived tyrannosaurs such as Tyrannosaurus. Its hands, which are also relatively large were believed to have had three fingers. Brusatte et al. (2011), however, observed an overall similarity in the shape of the available phalanges of Dryptosaurus with those of derived tyrannosaurids and noted that Dryptosaurus may have had only two functional digits. Each of its fingers were tipped by a talonlike 8 inch claw. Its forelimb morphology suggests that forelimb reduction in tyrannosauroids may not have proceeded in a uniform fashion.Dryptosaurus may have used both its arms and its jaws and as weapons when hunting, capturing and processing prey. The type specimen is a fragmentary skeleton belonging to a single adult individual. ANSP 9995 consists of a fragmentary right maxilla, a fragmentary right dentary, a fragmentary right surangular, lateral teeth, 11 middle-distal caudal vertebrae, both the left and right humeri, three manual phalanges from the left hand (I-1, II-2, and an ungual), the shafts of the left and right pubis bones, a fragmentary right ischium, the left femur, the left tibia, the left fibula, the left astragalus, and a midshaft fragment of metatarsal III. The ontological maturity of the holotype individual is supported by the fact that the neurocentral sutures are closed in all of its caudal vertebrae.AMNH FARB 2438 consists of left metatarsal IV, which likely from the same individual as the holotype.