Euparkeriidae

'' Euparkeriids, as well as several other advanced archosauriformes or early archosaurs (Dorosuchus, Dongusuchus, gracilisuchids) were lightly built and agile terrestrial carnivores which likely competed with cynodonts for food. They had gracile but well-ossified femurs which were capable of, but not well adapted for, bipedalism and cursoriality. , and an euparkeriid specimen similar to it (previously thought to be a new species of the gracilisuchid Turfanosuchus'') Most taxa which can be assigned to Euparkeriidae are incomplete, and shared synapomorphies (defining characteristics) are difficult to assess between members of the family. The only uniting trait observable in Euparkeria, Halazhaisuchus, and Osmolskina (the only genera believed to be valid euparkeriids) relates to their osteoderms. Euparkeriids had two rows of small keeled osteoderms with characteristically pointed anterior processes, although some osteoderms referred to Osmolskina are shorter and blunter than those characteristic of the other genera. Euparkeria and Osmolskina are united by several more traits which may characterize the family but are unknown in the rather incomplete Halazhaisuchus. These include an anterolaterally opening pit on the front of the maxilla, four premaxillary teeth, two exits for the hypoglossal nerve on the exoccipital, and separate interparietals (or postparietals). Osmolskina, Halazhaisuchus, and the dubious (but likely euparkeriid) "Turfanosuchus" shageduensis form a clade within Euparkeriidae united by the presence of a pronounced tuber on the scapula for the m. triceps. ==Classification==

Besides Euparkeria, the most completely known putative euparkeriid is Osmolskina czatkowicensis. Several hundred isolated bones have been found in Poland and referred to this genus. A 2010 phylogenetic analysis found that Osmolskina was more distantly related to Euparkeria than had previously been suspected, although in 2016 it was reinstated as a member of the family. }} Sookias (2016) also performed another study on Euparkeriidae using both parsimony and Bayesian analysis. This study found Halazhaisuchus, Osmolskina, and "Turfanosuchus" shageduensis to all be valid members of a monophyletic (albeit poorly supported) Euparkeriidae, and more closely related to each other than to Euparkeria. Dorosuchus was placed outside Euparkeriidae. The strict consensus tree of the parsimony analysis is given below: }} The Bayesian analysis resolved the trichotomy within Euparkeriidae and recovered Halazhaisuchus and Osmolskina as sister taxa. However, other parts of the tree lost much resolution creating a large polytomy of large groups above Erythrosuchidae. This analysis is given below: }} ==References==