FIG. 53 in Mystacodon selenensis, the earliest known toothed mysticete (Cetacea, Mammalia) from the late Eocene of Peru: anatomy, phylogeny, and feeding adaptations

FIG. 53. — Scatter plot showing the orbit orientation (measured as the posterolateral angle of the longitudinal axis of the orbit with the transverse plane) plotted against maximum orbital diameter vs the bizygomatic width. Color code: red, archaeocetes; green, toothed mysticetes; dark blue, fossil toothless mysticetes; light blue, extant mysticetes; orange, extant pinnipedimorphs; brown, fossil pinnipedimorphs. Plot modified from Marx (2011). Abbreviations: 1) archaeocetes: Ac, Artiocetus clavis; At, Aegyptocetus tarfa; Bi, Basilosaurus isis; Cp, Cynthiacetus peruvianus; Da, Dorudon atrox; Gv, Georgiacetus vogtlensis; So, Saghacetus osiris; Zk, Zygorhiza kochii; 2) toothed mysticetes: Ac, Aetiocetus cotylalveus; Aw, Aetiocetus weltoni; ChM PV 4745 and 5720, undescribed specimens from the Charleston Museum; Ch, Coronodon havensteini; Fb, Fucaia buelli; Fg, Fucaia goedertorum; Jh, Janjucetus hunderi; Mc, Mammalodon colliveri; Ms, Mystacodon selenensis; 3) chaeomysticetes: Am, Aglaocetus moreni; Ap, Aglaocetus patulus; Bm, Balaena mysticetus; Bb, Balaenella brachyrhynchus; Ba, Balaenoptera acutorostrata; Bp, Balaenoptera physalus; Bs, Balaenoptera siberi; Cm, Caperea marginata; Cr, Cetotherium rathkii; Dh, Diorocetus hiatus; Ea, Eubalaena australis; Eg, Eubalaena glacialis; Ej, Eubalaena japonica; Er, Eschrichtius robustus; Ia, Incakujira anillodefuego; Il, Isanacetus laticephalus; Me, Mixocetus elysius; Mm, Megaptera miocaena; Mn, Megaptera novaeangliae; Mp, Miocaperea pulchra; Pc, Pelocetus calvertensis; Pn, Piscobalaena nana; Pp, Parietobalaena palmeri; Yc, Yamatocetus canaliculatus; 4) Pinnipedimorphs: Ap, Arctocephalus philippii; Cc, Cystophora cristata; Db, Desmatophoca brachycephala; Et, Enaliarctos tedfordi; Hc, Homiphoca capensis; Hg, Halichoerus grypus; Hl, Hydrurga leptonyx; Ns, Neomonachus schauinslandi; Or, Ommatophoca rossii; Pb, Pteronarctos bishopi; Ph, Phocarctos hookeri; Pp, Piscophoca pacifica; Pr, Proneotherium repenningi; Pv, Phoca vitulina; Zc, Zalophus californianus.