# toothless mammal with keratin scales

Pennaraptoran Theropod Dinosaurs Past Progress and New Frontiers » Aug 21, 2020… 336. Hou, L.H., L.D. Martin, Z.H. Zhou, A. Feduccia, and F.C. Zhang. 1999a. A diapsid skull in a new species of the … Bioone.org

Fig. 3. Maxillae of Nqwebasaurus thwazi (AM 6040) and Pelecanimimus… » Download scientific diagram | Maxillae of Nqwebasaurus thwazi (AM 6040) and Pelecanimimus polyodon (LH 7777). (A-D) Left maxilla of Nqwebasaurus in: (A) medioventral view; (B) line drawing of medioventral view; (C) medial view; (D) line drawing of medial view; (E) lateral view of right maxilla of Pelecanimimus; (F) closeup of right maxilla of Pelecanimimus in lateral view with features outlined. Vertical arrow in (A-D) indicates dorsal direction, horizontal arrow indicates anterior direction. Dashed oval in (E) shows magnified area. Abbreviations: aofe, antorbital fenestra; aofo, antorbital fossa; fos, fossa; jrm, jugal ramus of the maxilla; mf, maxillary fenestra; mpr, maxillary palatal ridge; mt, maxillary teeth; npg, nasal/premaxillary articular groove; nrm, nasal ramus of the maxilla; tmt, posterior terminus of maxillary tooth row. Scale bars equal 1 cm; (F) not to scale. from publication: New information on Nqwebasaurus thwazi, a coelurosaurian theropod from the Early Cretaceous Kirkwood Formation in Sou Researchgate.net

Loss of teeth and enamel in tetrapods: fossil record, genetic data and morphological adaptations » Since their recruitment in the oral cavity, approximately 450 million years ago, teeth have been subjected to strong selective constraints due to the crucial role that they play in species survival. It is therefore quite surprising that the ability to… Ncbi.nlm.nih.gov