Data from: Redescription of Arganasaurus (Metoposaurus) azerouali (Dutuit) comb. nov. from the Late Triassic of the Argana Basin (Morocco), and the first phylogenetic analysis of the Metoposauridae (Amphibia, Temnospondyli)

A systematic revision of the temnospondyl ‘Metoposaurus’ azerouali Dutuit
from the Late Triassic of the Argana Basin (Western High Atlas, Morocco)
is presented. The type material is redescribed in detail, and a
preliminary phylogenetic analysis – the first one dealing with all
metoposaurid species – is also conducted in order to test its position
within the Metoposauridae. Our analysis places ‘Metoposaurus’ azerouali as
sister‐taxon to Arganasaurus lyazidi in a robust clade supported by two
unambiguous synapomorphies (bulge‐like tabular horn and exoccipital
process visible in dorsal view) and two ambiguous synapomorphies
(cultriform process of uniform width and subtriangular posterior Meckelian
fenestra). We therefore propose the new combination Arganasaurus azerouali
comb. nov. for the species ‘M.’ azerouali. Our analysis also confirms that
the central Laurasian genus Metoposaurus is monophyletic but not the genus
Koskinonodon, which deserves its own systematic revision. By consequent,
the Late Triassic rich vertebrate fauna from the Argana Basin comprises
the metoposauroid Almasaurus habazzi, the basal metoposaurid Dutuitosaurus
ouazzoui, and the genus Arganasaurus which is represented by the type
species A. lyazidi and A. azerouali comb. nov. Combined with the
stratigraphical and geographical occurrences of the taxa, our phylogenetic
analysis suggests that metoposaurids may have appeared during the
Longobardian (late Ladinian) in central Pangea. Their diversification may
be linked to the Carnian Pluvial Episode. At least, their extinction may
have occurred during the Rhaetian because of the aridification of the
climate and/or competition with amniotes.