Pamparaptor (, meaning "thief of the Pampas") is an extinct genus of paravian theropod dinosaur from the Late Cretaceous Portezuelo Formation of the Neuquén province in Argentine Patagonia. Its precise classification is uncertain, but the authors who described this taxon have argued that it is a dromaeosaurid. The genus contains a single species, P. micros (from the Greek word for "small"), which is known from a single specimen consisting of a mostly complete and fully-articulated left foot, which preserves the iconic dromaeosaur-like "killing claw".
Discovery The type and only specimen of Pamparaptor was discovered in 2005 by a technician named Diego Rosales who was working for the Lake Barreales Paleontological Center (or CePaLB) at the National University of Comahue. It was found at a locality called the "Baal Quarry", which is an outcrop of the Portezuelo Formation dated to the late Turonian or early Coniacian. The locality is on the northern shore of Lake Barreales Lake and about 90 kilometres (56 mi) northwest of the city of Neuquén. The specimen was reposited at the National University of Comahue and was given the designation MUCPv-1163. It consists of all three metatarsals, a complete second toe including the ungual, and two phalanges each from the third and fourth toes from the left foot of the same animal. These elements were discovered in articulation with one another and so they can be reasonably inferred to have been from the same animal. The holotype specimen of Pamparaptor was first reported in the literature in 2007 by the same researchers who would later go on to describe it. The specimen bore some similarities to the contemporaneous taxon Neuquenraptor, but was much smaller. For those reasons, MUCPv-1163 was believed to be a juvenile or subadult specimen of Neuquenraptor. Pamparaptor was finally described as a new genus in a publication of the Annals of the Brazilian Academy of Sciences in 2010 by a team of researchers including Juan Porfiri, Jorge Calvo, and Domenica Dos Santos. The authors remarked in the paper that their description is brief, but explained that they are confident that the remains cannot belong to any pre-existing taxon known from the Portezuelo Formation.
Description Pamparaptor was a small dromaeosaur. The entire length of the metatarsal (the longest bone in the foot) is only about 9.3 centimetres (3.7 in). The specimen is highly incomplete, but Porfiri and colleagues used the size of the foot to estimate that the animal would have been between 0.5 metres (1.6 ft) and 0.7 metres (2.3 ft) long in life. They did not give an estimate of the animal's mass. Rubén Molina-Pérez and Asier Larramendi gave a slightly greater length estimate of about 1.15 metres (3.8 ft) long and they also gave a weight estimate of 2.6 kilograms (5.7 lb) in weight. In their description of Pamparaptor, Porfiri and colleagues diagnose the genus as distinct from all other deinonychosaurs by the following synapomorphies: a slender and transversely compressed fourth metatarsal, an almost-equal length of the third and fourth metatarsals, a non-ginglymoidal joint on the distal end of the third metatarsal, a slight distal overlapping of the third metatarsal by the second, a proximal widening of the second metatarsal to double the width of either of the other two, a difference in length between the phalanges of the second toe, and a small sulcus on the distal end of the second metatarsal.
Classification
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