Relationships of the Indian phytosaur Parasuchus hislopi Lydekker, 1885

Abstract

The neotype skull of the Indian phytosaur Parasuchus hislopi Lydekker, 1885 (ISI R42) is re‐evaluated and compared with the type material of other basal phytosaurs. Parasuchus hislopi is extremely similar to species previously placed in Paleorhinus (P. bransoni and P. angustifrons), sharing with them such characters as a series of nodes on the lateral surface of the jugal, paired ridges on the squamosal and a frontal depression. Parasuchus hislopi represents a valid species: it can be distinguished from P. bransoni by a relatively low narial eminence and P. angustifrons by the absence of paired nasal depressions. Inclusion of Parasuchus hislopi in a phylogenetic analysis of phytosaurs recovers it in a well‐supported clade with P. bransoni and P. angustifrons. Parasuchus is considered the senior synonym of Paleorhinus and Arganarhinus. Parasuchus (here considered to include P. hislopi, P. angustifrons, P. bransoni and P. magnoculus) has a broad circum‐Pangaean distribution, with species occurring in the south‐western United States, Morocco, central Europe and India. Phytosaur higher‐level taxonomy is also revised: Parasuchidae is redefined to include ‘Paleorhinus‐grade’ phytosaurs and the later‐diverging Mystriosuchinae (the group formerly known as Phytosauridae), and Pseudopalatinae is renamed Mystriosuchini for reason of priority.

A Short-Snouted, Middle Triassic Phytosaur and its Implications for the Morphological Evolution and Biogeography of Phytosauria

“…Phytosaurs are well known from a near global distribution in the Late Triassic51415, with the earliest recognized taxa ( Wannia scurriensis, Parasuchus , ‘ Zanclodon ’ arenaceus ) known from the latest Carnian or earliest Norian16171819. The only specimen that was potentially older was the now-destroyed Mesorhinosuchus fraasi , said to be from the Olenekian of Germany, but this age is controversial151617.…”

“…The only specimen that was potentially older was the now-destroyed Mesorhinosuchus fraasi , said to be from the Olenekian of Germany, but this age is controversial151617. By the earliest Norian, phytosaurs had achieved their near global distribution across Pangea (i.e., including current-day India, North America, Morocco, and northern Europe), and all Late Triassic phytosaurs possessed the extremely elongated rostrum and dorsally-facing external nares that sit well posterior on the rostrum.…”

“…Yet, because the focus was on features clearly unique to phytosaurs this was detrimental to placing the clade in a broader evolutionary framework. A recent surge in species descriptions and subsequent taxonomic revisions161718202122, especially near the base of Phytosauria, has driven a more detailed examination and atomization of the entire phytosaur skull rather than characterizations of the most prominent features (i.e. the elongation and crests of the rostrum).…”

Neural and endocranial anatomy of Triassic phytosaurian reptiles and convergence with fossil and modern crocodylians

“…Time-calibrated phylogeny based on Stocker & Butler (2013), Kammerer et al (2016) and Ezcurra (2016). Endocasts of Parasuchus angustifrons and Ebrachosuchus neukami shown after retrodeformation.…”

“…Here, we describe the endocranial anatomy (including the brain, inner ear, neurovascular structures and sinus systems) of the two non-mystriosuchine phytosaurs Parasuchus angustifrons (=“ Paleorhinus angustifrons ”) and Ebrachosuchus neukami (Butler et al, 2014) (see Kammerer et al, 2016, for recent taxonomic revisions) (Fig. 1) based on digital reconstructions.…”