Comparison of the skull in dorsal view of Hyaenodontidae (left) and Hyainailouridae (right).

<p>See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.t001" target="_blank">Table 1</a> for description of the numbered features. Left: skull of <i>Sinopa grangeri</i> redrawn after Matthew ([<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref055" target="_blank">55</a>], <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.g004" target="_blank">Fig 4</a>); right: skull of <i>Apterodon macrognathus</i> redrawn after Osborn ([<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref056" target="_blank">56</a>]; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.g001" target="_blank">Fig 1A</a>).</p

Comparison of the geographic distribution of Hyaenodontidae (top) and Hyainailouridae (bottom).

<p>White: no fossils recorded; Grey: limited diversity; Black: main radiation.</p

Comparison of the skull in posterior (upper) and lateral (middle) views and of the mandible in labial view (lower) of Hyaenodontidae (left) and Hyainailouridae (right).

<p>See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.t001" target="_blank">Table 1</a> for description of the numbered features. Upper: skulls of <i>Pterodon dasyuroides</i> (right) and <i>Hyaenodon compressus</i> (left) redrawn after Polly ([<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref038" target="_blank">38</a>]; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.g011" target="_blank">Fig 11A and 11B</a>); middle: skulls of <i>Limnocyon verus</i> (left) and <i>Apterodon macrognathus</i> (right) redrawn respectively after Matthew ([<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref058" target="_blank">58</a>]; Fig 53) and Szalay ([<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref057" target="_blank">57</a>], <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.g006" target="_blank">Fig 6</a>); lower: mandibles of <i>Limnocyon verus</i> (left) and <i>Apterodon macrognathus</i> (right) redrawn respectively after Matthew ([<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref058" target="_blank">58</a>]; Fig 53) and Szalay ([<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref057" target="_blank">57</a>], <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.g009" target="_blank">Fig 9</a>).</p

Occipital view of the skull of <i>Kerberos langebadreae</i> gen. & sp. nov. (holotype, MNHN.F.EBA 517).

<p>A, occipital view. B, drawing of the occipital view. Abbreviations: F. M., foramen magnum; Lamb. Cr., lambdoid crest; Oc., occipital; Oc. C., occipital condyle; Oc. Cr., occipital crest; P. Gl. Pr., postglenoid process; Par. Ap., paroccipial apophysis; Sag. Cr., sagittal crest; Sq., squamosal.</p

Stratigraphic repartition of the different subfamilies of specialized carnivorous mammals in Europe during the Paleocene and Eocene, with special attention to hyainailourines.

<p>The new taxon described here, <i>Kerberos langebadreae</i>, is in bold. Note that currently i. the stratigraphic extension of <i>Paroxyaena pavlovi</i> during Priabonian is unknown [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref008" target="_blank">8</a>] and ii. the age of <i>Parapterodon</i> is unknown but is estimated to be late Priabonian [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref009" target="_blank">9</a>]. Stratigraphic scale, eustatic curve, and isotopic curves produced with TSCreator [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref010" target="_blank">10</a>] from the data compiled by Gradstein et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref011" target="_blank">11</a>]. Abbreviations: ELMA, European Land Mammal Ages; MP, Mammal Palaeogene.</p

Drawings of the skull of <i>Kerberos langebadreae</i> gen. & sp. nov. (holotype, MNHN.F.EBA 517).

<p>A, dorsal view; B, ventral view; C, left lateral view; D, right lateral view. Abbreviations: Al., alisphenoid; An. C. F., anterior condyloid foramen; Bas., basisphenoid; F. M., foramen magnum; F. Ov., foramen oval; Fr., frontal; Inc. F., incisive foramen; Infr. F., infraorbital foramen; J., jugal; La., lacrimal; Mas. Ap., mastoid apophysis; Mas. Par. Ap., mastoid-paroccipital apophysis; Mas. Pr., mastoid process; Max., maxilla; Na., nasal; Oc. C., occipital condyle; Oc., occipital; Op. F., optic foramen; P. Gl. Pr., postglenoid process; Pa., parietal; Pal., palatine; Par. Ap., paroccipial apophysis; Po. F., posterior pterygoid foramen; Pr. Gl. Pr., preglenoid process; Premax., premaxilla; Sag. Cr., sagittal crest; Sq., squamosal; To. Pal., torus palatinus.</p

Skull of <i>Kerberos langebadreae</i> gen. & sp. nov (holotype, MNHN.F.EBA 517).

<p>A, dorsal view; B, ventral view; C, left lateral view; D, right lateral view.</p

Geographic map with indications of the location of the fossiliferous locality of Montespieu (MP16), where material of <i>Kerberos langebadreae</i> was found.

<p><b>A,</b> Localisation of the department of Tarn (France). <b>B,</b> Localisation of Montespieu in Tarn. B: redrawn after Laurent et al. ([<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.ref025" target="_blank">25</a>], <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135698#pone.0135698.g001" target="_blank">Fig 1</a>).</p

Comparison of the hemimandibles in labial view of hyainailourines.

<p><i>Furodon crocheti</i> (A, left inverted, HGL 50bis-56; HGL, Hammada Gour Lazib, Algeria, Université Montpellier 2, France), <i>Kerberos langebadreae</i> gen. & sp. nov. (B, holotype, left inverted, MNHN.F.EBA 518b) and “<i>Pterodon</i>” <i>phiomensis</i> (C, right, AMNH 13253; AMNH, American Museum of Natural History, New York, USA). Not to scale</p

Strict consensus of the third phylogenetic analysis of the hyainailourines with <i>Leakitherium</i> and body mass character excluded.

<p>111 steps long; CI 0.60; RI 0.76; with indications of the Bremer support values. In bold: <i>Kerberos langebadreae</i> gen. & sp. nov.</p