Sunday, April 18, 2010
Species: P. chiniquensis and P. loricatus
Nominal Author: Huene 1942
Age: Ladinian - Carnian (Middle/Late Triassic)
Location: Santa Maria Formation, Brazil
Physical Characteristics: Large (~5 meters) quadrupedal predator with an erect posture
Prestosuchus was originally described by Friedrich von Huene in 1942 as two different species: P. chiniquensis and P. loricatus. However, because of the amount of material and Huene's failure to designate holotype specimens, Prestosuchus taxonomy has been problematic. Krebs (1976) has suggested that the two Prestosuchus species are in fact synonymous and Barberena (1978) presented a specimen as being the skull of Prestosuchus. Brusatte et al (2010) have recently concluded that if the Barberena skull and the Huene material do indeed represent different taxa, then they are at least very closely related. A detailed revision of Prestosuchus taxonomy is currently being performed by Julia B. Desojo.
Prestosuchan (and Rauisuchan, for that matter) phylogenetics has been extremely problematic. Fortunately, a recent study by Brusatte et al (2010) seems to have sorted things out. Prestosuchus and Batrachotomus have been shown to compose a sister taxon pair with an 81% bootstrap value. Prestosuchidae Romer 1966 is described the most inclusive clade containing Prestosuchus chiniquensis Huene 1942 but not Rauisuchus tiradentes Huene 1942. By the Brusatte phylogeny, Prestosuchidae therefore consists of Prestosuchus, Batrachotomus, and Saurosuchus. Moving out further in the phylogeny, we get Rauisuchoidea which includes Prestosuchidae plus Rauisuchidae and a basal cluster which includes Ticinosaurus. Finally, we see a monophyletic Rauisuchia made up of Rauisuchoidea and Poposauroidea.
This is the first in a series of weekly posts I will be making. Every Sunday, I will feature an overview of a Crurotarsan species (or genus for that matter). I will mostly choose at random but requests are welcome.