During this time period, lydekkerinids were widely distributed, with putative remains reported from Russia, Greenland, India, South Africa, Madagascar, Australia, and Antarctica.

The identification of features shared among lydekkerinids (synapomorphies) necessarily varies depending on which taxa are considered to belong to this group (see further in next section).

For example, Schoch & Milner (2000) considered all nominal lydekkerinids to belong to this family and listed featured like longitudinally oval, unpaired anterior palatal openings, with a pointed posterior end; and a broad and laterally extensive postorbital and prefrontal as synapomorphies.

[18] Luzocephalus, which would be the largest of the lydekkerinids with a skull length over 15 cm,[19] has often been found to be more closely related to a family called Trematosauridae, such as in the study by Yates and Warren (2000).

[2][8] Below is a cladogram from Yates and Warren (2000) showing the polyphyly:[10] Peltobatrachus Lapillopsis Rhinesuchidae Lydekkerina Mastodonsaurus Benthosuchus Capitosauridae Luzocephalus Thoosuchus Trematosauridae Almasaurus Buettneria Laidleria Plagiosauridae Rhytidosteidae Keratobrachyops Pelorocephalus Siderops Xenobrachyops Batrachosuchus The phylogenetic analysis of Damiani (2001) resulted in a monophyletic Lydekkerinidae, although it was only weakly supported and included what is now recognized as the small-bodied Early Triassic capitosaur Edingerella madagascariensis.