Piatnitzkysaurus ‭(‬Piatnitzky’s lizard‭ ‬-‭ ‬in honour of the palaeontologist Alejandro Mateievich Piatnitzky‭)

Short Info

Piatnitzkysaurus ‭(‬Piatnitzky’s lizard‭ ‬-‭ ‬in honour of the palaeontologist Alejandro Mateievich Piatnitzky‭)

Phonetic : Pee-at-nits-kee-sore-us.

Named By : Jose Bonaparte‭ ‬-‭ ‬1979

Diet : Carnivore

Size : Estimated 4.3 meters long

Type of Dinosaur : Large Theropod

Type Species : P.‭ ‬floresi‭ (‬type‭)‬

Found in : Argentina‭ ‬-‭ ‬Canadon Asfalto Formation

When it Lived : Late Jurassic, 164-159 million years ago

Piatnitzkysaurus (/,pi:@tnItski:’so:r@s/ pee-@t-NYITS-kee-SOR-@s meaning “Piatnitzky’s lizard”) is a genus of megalosauroid theropod dinosaur that lived approximately 179 to 177 million years ago during the lower part of the Jurassic Period in what is now Argentina. Piatnitzkysaurus, a bipedal, small-sized, ground-dwelling carnivore, could reach 6.6m (21.7 feet) in length.

Jose Bonaparte described the type species in 1979 as Piatnitzkysaurus Floresi. It was named in honor of Alejandro Matveievich Piatnitzky (1879-1959), an Argentine geologist born in Russia.


Piatnitzkysaurus mount japanケラトプスユウタ, CC BY-SA 4.0, via Wikimedia Commons


The holotype Piatnitzkysaurus specimen, PVL 4073 was found during three expeditions to the Canadon Asfalto Formation, in sediments that were deposited in the Middle-Late Toarcian period of the Jurassic Period, around 179 to 173 million years ago. It was once thought to have been a basal carnosaur but it was later designated a megalosauroid.

Two partial skeletons (a fractured skull, parts of two postcranial and paratype MACN CH 895) are all known. This is the best-known theropod from Southern Hemisphere’s Middle-Late Jurassic Period. Piatnitzkysaurus, a medium-sized bipedal carnivore of moderate build, was approximately 4.3m (14 ft), and weighed in at 450 kg (990 lb). However, these estimates do not include the holotype which is a subadult. It was strong with powerful hind legs and had four toes on each of its feet. Its ischium measures 423 millimetres (or 16.7 inches) in length. Its braincase is similar to that of the megalosauroid Piveteausaurus, a megalosauroid from France.

Benton (1992) noted a general resemblance between the Allosaurus theropod and the Piatnitzkysaurus. However, there are important differences. Piatnitzkysaurus’ scapular blade is longer and wider than other derived tenaurans. The humerus is 50 percent longer than the femur. This primitive condition is common among basal theropods. The relative lengths between the ulna and the humerus are similar to those of basal toropods. This means that the forelimbs in Piatnitzkysaurus have a proportionally greater length than in Allosaurus. Primitive is also the contact between the pubis (ischium) and the pubis, which is a different condition than the Allosaurus and more derived Tetanurans in which the contact is decreased. Piatnitzkysaurus’ pubis also has a distal leg that is less developed than Allosaurus.

Piatnitzkysaurus has a strong resemblance. It was suggested that Condorraptor, the sister tax, could be better understood as an individual variation within the species and not as a separate taxa. Condorraptor has a shorter enemialcrest and a lower first sacral vertebra. Condorraptor’s fossa is shallower.

Source: Wikipedia