The Origin of Filter Feeding in Whales Jonathan H. Geisler, Robert W. Boessenecker, Mace Brown, Brian L. Beatty  Current Biology  Volume 27, Issue 13, Pages 2036-2042.e2 (July 2017) DOI: 10.1016/j.cub.2017.06.003 Copyright © 2017 Elsevier Ltd Terms and Conditions

Figure 1 Cranium and Upper Dentition of Coronodon havensteini sp. et gen. nov. (A–E) Cranium in (A) lateral and (B) dorsal views. For comparison, (C) shows a dorsal view of the archaeocete Zygorhiza kochii (USNM 11962). Also shown of Coronodon are the left P3 in (D) labial and (E) lingual views. (F and G) Left M2 in (F) labial and (G) lingual views. (H and I) Right bulla in (H) dorsal view and left petrosal in (I) ventrolateral view. Portions in gray are reconstructed. ap, anterior process of petrosal; cp, conical apophysis; fr, fenestra rotunda; Fr, frontal; lt, ventrolateral tuberosity; mf, fossa for malleus; Mx, maxilla; Na, nasal; ol, outer lip of bulla; os, occipital shield; Pa, parietal; pc, pars cochlearis; pbf, posterior facet for bulla; pgp, postglenoid process; pp, posterior process of bulla; Px, premaxilla; sp, sigmoid process; Sq, squamosal; sc, sagittal crest; Vo, vomer; zy, zygomatic process; VII canal for facial nerve. Scale bars in (A)–(C), 10 mm. Scale bars in (D)–(I), 5 mm. Blue denotes dental wear and red denotes dental erosion. See also Figures S1, S2, S3, Table S1, and Data S1. Current Biology 2017 27, 2036-2042.e2DOI: (10.1016/j.cub.2017.06.003) Copyright © 2017 Elsevier Ltd Terms and Conditions

Figure 2 Filter Feeding in Coronodon havensteini and Associated Morphology (A) Left mandible in medial view. (B) Oblique anteromedial view of filter-feeding slots (indicated by arrows) between molars and p4. Orientation of view is shown in (A). (C–E) Left lower p4 in (C) labial, (D) lingual, and (E) occlusal views. (F) Schematic representation of hypothesized water flow (blue arrows) through the oral cavity during filter feeding, drawn from CT data after the mandibles were digitally articulated with the cranium. (G) Left mandible of the basilosaurid Cynthiacetus peruvianus in medial view, reproduced with permission from Martínez-Cáceres and de Muizon, 2011. (H) Tusk of the beaked whale, Mesoplodon stejnegeri (USNM 504731), in labial view. cp, coronoid process; mc, mandibular condyle; mf, mandibular fossa. Blue denotes dental wear and red denotes dental erosion. See also Figures S1 and S2, Tables S1 and S2, and Data S1. Current Biology 2017 27, 2036-2042.e2DOI: (10.1016/j.cub.2017.06.003) Copyright © 2017 Elsevier Ltd Terms and Conditions

Figure 3 Cranium of Coronodon havensteini in Anterior View See Figure 1 for abbreviations. Scale bar, 10 cm. See also Figure S2, Table S1, and Data S1. Current Biology 2017 27, 2036-2042.e2DOI: (10.1016/j.cub.2017.06.003) Copyright © 2017 Elsevier Ltd Terms and Conditions

Figure 4 Phylogenetic Position of Coronodon havensteini and Evolution of Key Features Associated with Filter Feeding On top are labial views of mandibles for selected taxa; below are reconstructions for tooth spacing and baleen in ancestral taxa. Grey shading in drawings indicates preserved portions. Circles summarize likelihoods of alternate discrete states for relative diastema length at internal branches, with legend in lower right. Ancestral reconstructions are based on the state with the highest likelihood. The presence of baleen is based on palatal nutrient foramina [5]. For parsimony optimization, see also Figure S4, Table S3, and Methods S1. Current Biology 2017 27, 2036-2042.e2DOI: (10.1016/j.cub.2017.06.003) Copyright © 2017 Elsevier Ltd Terms and Conditions