New Lizard Specimens from the Campanian Wapiti Formation of Alberta, Canada

Abstract

<p>Reported lizard material from the Wapiti Formation (central-western Alberta, Canada) is limited to fragmentary remains of <i>Kleskunsaurus grandeprairiensis</i> and <i>Socognathus unicuspis</i>, a partial dentary attributed to <i>Chamops</i> cf. C. <i>segnis</i>, and a vertebra reportedly comparable to those of the much larger lizard <i>Palaeosaniwa canadensis</i>. P. <i>canadensis</i> is a Late Cretaceous North American member of Monstersauria, a Mesozoic and Cenozoic anguimorph group represented today by five species of <i>Heloderma</i>. Here, we document new squamate material from the DC Bonebed locality (Wapiti Unit 3" Campanian), including a right frontal identified as cf. P. <i>canadensis</i> and a taxonomically indeterminate squamate astragalocalcaneum. A partial skeleton from the Two Medicine Formation of Montana provisionally attributed to P. <i>canadensis</i> has a frontal resembling the corresponding element from the DC Bonebed in overall shape, in having narrowly separated facets for the prefrontal and postorbitofrontal, and in bearing osteoderms similar to the DC specimen's in ornamentation and configuration. The Two Medicine and DC specimens differ from a roughly contemporaneous frontal from southern Alberta referred to the monstersaur <i>Labrodioctes montanensis</i>. The DC specimen confirms the presence of monstersaurian squamates in the Wapiti Formation, representing the northernmost record of any definitive Late Cretaceous monstersaur to date.</p>