Mapusaurus
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Mapusaurus Temporal range: Late Cretaceous, 95 Ma |
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| Reconstructed skeletons of an adult and a juvenile (left) | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Order: | Saurischia |
| Suborder: | Theropoda |
| Family: | †Carcharodontosauridae |
| Tribe: | †Giganotosaurini |
| Genus: |
†Mapusaurus Coria & Currie, 2006 |
| Species | |
Mapusaurus ("earth lizard") was a giant carnosaurian dinosaur from the early Late Cretaceous (Cenomanian stage) of what is now Argentina.
It was similar in size to its close relative Giganotosaurus, with the largest known individuals estimated as about 12.2 metres (40 ft) in length or more and weighing similarly to Giganotosaurus. The longest individual for which Coria and Currie (2006) provided a concrete estimate in Table 1 ( apendix lll) is the animal to which femur MCF-PVPH-208.203 belonged; this individual is estimated as 10.2 metres (33 ft) long.
Coria and Currie note the presence of isolated bones from at least one longer individual, but do not provide a figure, instead finding the larger bones coherent with an individual of comparable size to Giganotosaurus holotype estimated at 12.2 metres (40 ft) in length, although not with the same exact proportions, having taller and wider neural spines, a more elongate fibula (86 cm compared to 83.5 cm) but more slender (81-89% the width as in Giganotosaurus) as well as a wider pubic shaft in minimal dimensions (10% wider as indicated by a 7.8 cm long fragment catalogued as MCF-PVPH-108.145), and with a differently proportioned skull, shorter in length than Giganotosaurus because the maxilla is not elongate ( 12 tooth compared to 14 in Carcharodontosaurus) but deeper in proportion due to this, as well as also narrower (due to the narrow nassals). Considering this, a fragmentary maxilla is coherent with the size of the Giganotosaurus sized individual (MCF-PVPH-108.169) . A neural arch from an axis ( MCF-PVPH-108.83) and a scapular blade fragment are also the same exact size as the same elements in Giganotosaurus. The weight estimate of 3000 kg is from a 1300 mm long femur with a 455 mm circumference (MCF-PVPH-208.234). Holtz estimated the maximum size of the animal at 12.6 metres (41 ft). this estimate is cited in Drew Eddy and Julia Clarke (2011). and cited again in a phylogenetic table in a 2014 analysis by Canale et al.
Coria and Currie diagnosed Mapusaurus as follows: "Mapusaurus n. gen. is a carcharodontosaurid theropod whose skull differs from Giganotosaurus in having thick, rugose unfused nasals that are narrower anterior to the nasal/maxilla/lacrimal junction; larger extension of the antorbital fossa onto maxilla; smaller maxillary fenestra; wider bar (interfenestral strut) between antorbital and maxillary fenestrae; lower, flatter lacrimal horn; transversely wider prefrontal in relation to lacrimal width; ventrolaterally curving lateral margin of the palpebral; shallow interdental plates; higher position of Meckelian canal; more posteriorly sloping anteroventral margin of dentary. Mapusaurus roseae is unique in that the upper quadratojugal process of jugal splits into two prongs; small anterior mylohyoid foramen positioned above dentary contact with splenial; second and third metacarpals fused; humerus with broad distal end and little separation between condyles; the brevis fossa of the ilium extends deeply into excavation dorsal to ischial peduncle. It also differs from Giganotosaurus in having conical, slightly curving cervical epipophyses that taper distally; axial posterior zygapohyses joined on midline; smaller and less elaborate prespinal lamina on midline of cervicals; remarkably sharp dorsal margin of cervical neural spines; tall, wider neural spines; curved ischiatic shaft; more slender fibula."
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