Fig 1.
A, map of Central America showing the localities. B, map of central Panama, showing the distribution of the Chagres Formation as well as the localities of fossil cetaceans mentioned in the text. C, chronostratigraphic and lithostratigraphic relationships of the Chagres Formation (modified from Hendy et al. [17]).
Table 1.
Measurements (in mm) of skulls of Nanokogia isthmia gen. et sp. nov. (modified from Perrin [18]).
Table 2.
Measurements (in mm) of mandible (UF 280000) of Nanokogia isthmia gen. et sp. nov. (modified from Perrin [18]).
Fig 2.
Dorsal view of holotype skull of Nanokogia isthmia gen. et sp. nov. (UF 280000).
Abbreviations: adif, anterior dorsal infraorbital foramen; an, antorbital notch; en, external nares; et, ethmoid; fr, frontal; la+j, lacrimal + jugal; lmc, lateral maxillary crest; mrg, mesorostral groove; mx, maxilla; pmx, premaxilla; pdif, posterior dorsal infraorbital foramen; scf, supracranial fossa; sfc, sagittal facial crest; sq, squamosal; vo, vomer. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.
Fig 3.
Ventral view of holotype skull of Nanokogia isthmia gen. et sp. nov. (UF 280000).
Abbreviations: an, antorbital notch; bo/bs, basioccipital/basisphenoid; boc, basioccipital crest; cb.e, cerebral endocast; eam, external auditory meatus; fg, frontal groove; in, internal nares; jn, jugular notch; la+j, lacrimal + jugal; ma, mandible; mx, maxilla; npp, notch for posterior process of tympanic; oc, occipital condyles; pl, palatine; prs, presphenoid; ptdl, dorsal lamina of pterygoid; ptha, pterygoid hamulus; ptml, medial lamina of pterygoid; ptsf, pterygoid sinus fossa; tsr, tympanosquamosal recess; vif, ventral infraorbital foramen; vo, vomer. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.
Fig 4.
Dorsal, 4A-B, and ventral, 4C-D, views of referred specimen of Nanokogia isthmia gen. et sp. nov. (UF 273554).
Abbreviations: amc, anterior meatal crest; as, alisphenoid; bo, basioccipital; boc, basioccipital crest; dif, dorsal infraorbital foramen; eam, external auditory meatus; en, external nares; fg, frontal groove; fo, foramen ovale; fp, falciform process of squamosal; fr, frontal; jf, jugular foramen; jn, jugular notch; la+j, lacrimal + jugal; lmc, lateral maxillary crest; mx, maxilla; oc, occipital condyles; pmx, premaxilla; pop, postorbital process; prp, preorbital process; prs, presphenoid; ptdl, dorsal lamina of pterygoid; ptml, medial lamina of pterygoid; ptsf, pterygoid sinus fossa; scb, supracranial basin; so, supraoccipital; sq, squamosal; tsr, tympanosquamosal recess; vif, ventral infraorbital foramen; vo, vomer. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.
Fig 5.
Left ventrolateral view of referred specimen of Nanokogia isthmia gen. et sp. nov. (UF 273554).
Abbreviations: amc, anterior meatal crest; as, alisphenoid; bo/bs, basioccipital/basisphenoid; boc, basioccipital crest; eo, exoccipital; fg, frontal groove; fm, foramen magnum; fo, foramen ovale; fp, falciform process of squamosal; fr, frontal; jf, jugular foramen; la+j, lacrimal + jugal; mx, maxilla; oc, occipital condyle; of, optic foramen; pgp, postglenoid process; pop, postorbital process; prs, presphenoid; ptdl, dorsal lamina of pterygoid; ptml, medial lamina of pterygoid; ptsf, pterygoid sinus fossa; sop, supraorbital process; sp, spiny process; sq, squamosal; tsr, tympanosquamosal recess; vif, ventral infraorbital foramen; vo, vomer; zp, zygomatic process. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.
Fig 6.
Right lateral view of holotype skull of Nanokogia isthmia gen. et sp. nov. (UF 280000).
Abbreviations: eo, exoccipital; fg, frontal groove; fr, frontal; la+j, lacrimal + jugal; ma, mandible; mx, maxilla; lmc, lateral maxillary crest; npp, notch for posterior process of tympanic; of, optic foramen; pa, parietal; pgp, postglenoid process; pmx, premaxilla; ptdl, dorsal lamina of pterygoid; ptha, pterygoid hamulus; ptml, medial lamina of pterygoid; ptn, pterygoid notch; ptsf, pterygoid sinus fossa; scb, supracranial basin; sfc, sagittal facial crest; sq, squamosal; tc, temporal crest; zp, zygomatic process. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.
Fig 7.
Left, 6A-B, and right, 6C-D, lateral views of referred specimen of Nanokogia isthmia gen. et sp. nov. (UF 273554).
Abbreviations: boc, basioccipital crest; eam, external auditory meatus; eo, exoccipital; fr, frontal; lmc, lateral maxillary crest; mx, maxilla; npp, notch for posterior process of tympanic; oc, occipital condyle; of, optic foramen; pa, parietal; pmx, premaxilla; pop, postorbital process; prp, preorbital process; prs, presphenoid; ptdl, dorsal lamina of pterygoid; ptml, medial lamina of pterygoid; scb, supracranial basin; smc, supramastoid crest; sq, squamosal; tc, temporal crest; vo, vomer; zp, zygomatic process. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.
Fig 8.
Posterior views of holotype (UF 280000), 7A-B, and referred specimen (UF 273554), 7CD, skulls of Nanokogia isthmia gen. et sp. nov.
Abbreviations: boc, basioccipital crest; eo, exoccipital; fm, foramen magnum; jn, jugular notch; oc, occipital condyles; so, supraoccipital; sop, supraorbital process of frontal; tc, temporal crest. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.
Fig 9.
Mandible of holotype (UF 280000) of Nanokogia isthmia gen. et sp. nov. in dorsal, 8A, right lateral, 8B, and left lateral 8C, views.
Abbreviations: al, tooth alveoli; ar, alveolar row; gn, gnathion; mf, mandibular fossa; ms, mandibular symphysis. Diagonal lines denote broken surfaces.
Fig 10.
Time-calibrated phylogeny of Pan-Physeteroidea.
Strict consensus tree resulting from three most parsimonious trees, 95 steps long, with CI = 0.589 and RI = 0.723. Arcs indicate stem-based taxa, while circles denote node-based clades; numbers below nodes indicate decay indices/bootstrap values; for definition of clades see text. Abbreviations: Aq., Aquitanian; Bar., Bartonian; Burd., Burdigalian; Chatt., Chattian; La., Langhian; M., Messinian; P., Piacenzian; Plio., Pliocene; Pleist., Pleistocene; Priab., Priabonian; Rupel., Rupelian; S., Serravallian; Tort., Tortonian; Z, Zanclean. (Time scale based on Cohen et al. [20].)
Fig 11.
Dorsal views of kogiid skulls.
Aprixokogia kelloggi (USNM 187015), 11A, Scaphokogia cochlearis (MNHN PPI 229), 11B, Praekogia cedrosensis (UCMP 315229), 11C, Nanokogia isthmia gen. et sp. nov. (based on UF 280000 and 273554), 11D, Kogia sima (LACM 47142), 11E, and, K. breviceps (LACM 95745), 11F. Each bone is color-coded for ease of comparison. Red dashed lines denote the extent of the supracranial/premaxillary fossa. Areas in white are not preserved and have been reconstructed with plaster on the specimens. Illustration of S. cochlearis modified from Muizon [8]; all other illustrations based on the specimens listed.
Fig 12.
Ventral views of kogiid skulls.
Aprixokogia kelloggi (USNM 187015), 12A, Scaphokogia cochlearis (MNHN PPI 229), 12B, Praekogia cedrosensis (UCMP 315229), 12C, Nanokogia isthmia gen. et sp. nov. (UF 273554), 12D, and (UF 280000), 12E, Kogia sima (LACM 47142), 12F, and K. breviceps (LACM 95745), 12G. Each bone is color-coded for ease of comparison. Areas in white are reconstructed, light gray areas are covered with sediment; diagonal lines denote broken surfaces. Illustrations based on direct observations of the specimens listed.
Fig 13.
Right lateral views of kogiid skulls.
Aprixokogia kelloggi (left side, reversed, USNM 187015), 13A, Scaphokogia cochlearis (MNHN PPI 229), 13B, Praekogia cedrosensis (UCMP 315229), 13C, Nanokogia isthmia gen. et sp. nov. (based on UF 280000 and 273554), 13D, Kogia sima (LACM 47142), 13E, and K. breviceps (LACM 95745), 13F. Each bone is color-coded for ease of comparison. Areas in white are reconstructed; diagonal lines denote broken surfaces. Illustrations based on direct observations of the specimens listed.
Fig 14.
Anterodorsal views of kogiid skulls.
Aprixokogia kelloggi (USNM 187015), 14A, Scaphokogia cochlearis (MNHN PPI 229), 14B, Praekogia cedrosensis (UCMP 315229), 14C, Nanokogia isthmia gen. et sp. nov. (UF 280000), 14D, Kogia sima (LACM 47142), 14E, and K. breviceps (LACM 95745), 14F; each bone is color-coded for ease of comparison. Red dashed lines denote the extent of the supracranial/premaxillary fossa. Areas in white are reconstructed, light gray areas are covered with sediment; diagonal lines denote broken surfaces.