''Asfaltovenator'' (meaning "Cañadón Asfalto Formation hunter" after the fossil formation in which its fossils were found) is a genus of possibly allosauroid

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

from the

Lower Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma&nb ...

Cañadón Asfalto Formation The Cañadón Asfalto Formation is a Lower Jurassic to Late Jurassic geologic formation, from the Jurassic period of the Mesozoic Era. Its age is controversial, uranium-lead dating of the volcanic tuff beds having given various different age ...

from

Chubut Province Chubut ( es, Provincia del Chubut, ; cy, Talaith Chubut) is a province in southern Argentina, situated between the 42nd parallel south (the border with Río Negro Province), the 46th parallel south (bordering Santa Cruz Province), the Ande ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the List of South American countries by area, second-largest ...

. The type and only species is ''Asfaltovenator vialidadi''.

Discovery

In 2002, technician Leandro Canesa, roughly a

mile The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and United States customary unit of distance; both are based on the older English unit of length equal to 5,280 Engli ...

north of Cerro Condor, discovered a theropod skeleton. Excavations started in 2005. In 2007, the fossil was in its entirety removed as an enormous stone block, covered by plaster of Paris. It was then prepared by Mariano Caffa, a process that took five years due to the extreme hardness of the stone matrix. Between 2013 and 2015, it was compared with the specimens of related theropods, researchers personally investigating their exemplars in collections all over the world. In 2019, the type species ''Asfaltovenator vialidadi'' was named and described by Oliver Walter Mischa Rauhut and Diego Pol. The generic name combines a reference to the Cañadón Asfalto with a

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

''venator'', "hunter". The specific name honours the ''Dirección Nacional de Vialidad'', for assisting the ''Museo Paleontológico "Egidio Feruglio"'' in recovering the fossil. ''Asfaltovenator'' is only known from the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

specimen MPEF PV 3440, which was found in a layer of the Cañadón Asfalto Formation which dates from the late

Toarcian The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian. The Toar ...

to the

Bajocian In the geologic timescale, the Bajocian is an age and stage in the Middle Jurassic. It lasted from approximately 170.3 Ma to around 168.3 Ma (million years ago). The Bajocian Age succeeds the Aalenian Age and precedes the Bathonian Age. Stra ...

, being latter fully constrained to 179-178 million years (Middle-Late Toarcian) thanks to advanced zircon datation. It consists of a partial skeleton with skull. It contains the largely complete skull with lower jaws and the front half of the skeleton forward of the hips, including ten neck vertebrae, thirteen back vertebrae and the first sacral vertebra, the complete shoulder girdle minus the furcula and both forelimbs; and also the distal portion of the

pubic bones In vertebrates, the pubic region ( la, pubis) is the most forward-facing (ventral and anterior) of the three main regions making up the coxal bone. The left and right pubic regions are each made up of three sections, a superior ramus, inferior r ...

as well as a partial right hindlimb consisting of the distal portion of the femur and proximal portions of the tibia and fibula, and a partial foot.

Description

''Asfaltovenator'' was a fairly large animal, with the holotype skull being seventy-five to eighty centimetres in length and the total body length being estimated at seven to eight metres. The describers indicated a number of distinguishing traits. Some of these are

autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

, unique derived characters. The premaxillary teeth have large serrations on the rear edge but only minute serrations on the front edge. The exoccipital bone of the rear skull shows distinctive horizontal ridges between the paraoccipital process and the

foramen magnum The foramen magnum ( la, great hole) is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblon ...

. On the third and fourth neck vertebrae, the neural spines are triangular and swept backwards. The eleventh and twelfth back vertebrae possess an additional forward ridge on the underside of the diapophysis, the process for the articulation facet of the top rib head.

Classification

Due to its mosaic of primitive and derived characters within Tetanurae, ''Asfaltovenators inclusion in the phylogenetic analysis disrupted current views of tetanuran phylogeny, with the analysis recovering ''Asfaltovenator'' as a basal allosauroid, above the Piatnitzkysauridae, and traditional Megalosauroidea as a

paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...

grade leading to

Allosauroidea Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. Allosauroids, alongside the family Megalosauroidea, were amo ...

. The unique combination of characteristics seen in ''Asfaltovenator'' may also indicate megalosauroids and allosauroids shared a common ancestor not shared with the tetanuran group of

Coelurosauria Coelurosauria (; from Greek, meaning "hollow tailed lizards") is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, t ...

References

{{Taxonbar, from=Q78185607 Carnosaurs Toarcian life Bajocian life Middle Jurassic dinosaurs of South America Jurassic Argentina Fossils of Argentina Fossil taxa described in 2019 Cañadón Asfalto Basin