A new kentriodontid dolphin (Cetacea, Odontoceti, Delphinida) from the Middle Miocene of the southeastern Pacific Author Lambert, Olivier D. O. Terre et Histoire de la Vie, Institut royal des Sciences naturelles de Belgique, 29 rue Vautier, B- 1000 Brussels (Belgium) olambert @ naturalsciences. be (corresponding author) olambert@naturalsciences.be Author Oberlin, Maëlle Université de Strasbourg, CNRS, IPHC UMR 7178, F- 67000 Strasbourg (France) and Centre d’Études biologiques de Chizé, CNRS, UMR 7372, F- 79360 Villiers en Bois (France) maelle. oberlin. pro @ gmail. com maelle.oberlin.pro@gmail.com Author Muizon, Christian de CR 2 P (CNRS, MNHN, Sorbonne Université), Département Origines et Évolution, Muséum national d’Histoire naturelle, case postale 38, 57 rue Cuvier, F- 75231 Paris cedex 05 (France) muizon @ mnhn. fr muizon@mnhn.fr Author Collareta, Alberto Dipartimento di Scienze della Terra, Università di Pisa, via S. Maria 53, I- 56126 Pisa (Italy) alberto. collareta @ unipi. it alberto.collareta@unipi.it Author Urbina, Mario Departamento de Paleontología de Vertebrados, Museo de Historia Natural-Universidad Nacional Mayor de San Marcos, Avenida Arenales 1256, P- 15072 Lima (Peru) mariourbina 01 @ hotmail. com mariourbina01@hotmail.com Author Bianucci, Giovanni Dipartimento di Scienze della Terra, Università di Pisa, via S. Maria 53, I- 56126 Pisa (Italy) giovanni. bianucci @ unipi. it giovanni.bianucci@unipi.it text Geodiversitas 2026 2026-02-19 48 3 25 50 journal article 314273 10.5252/geodiversitas2026v48a3 14836d91-e4fd-4c65-926a-159ed6a4efb5 1638-9395 18700562 urn:lsid:zoobank.org:pub:6DFFE442-7DE6-42CF-B184-5B94B354FB36

TABLE 1. — Cranial measurements (in mm) of Mesokentriodon protohumboldti n. gen., n. sp. MNHN.F.PPI282, MNHN.F.PPI283, and MUSM4693. Abbreviations: +, incomplete; e, estimate; –, no data; (r), right side, (l), left side.

	MNHN.F.PPI282 (holotype)	MNHN.F.PPI283 (paratype)	MUSM 4693
condylobasal length	+480	+440	+417
rostrum length	324	292	+279
width of rostrum at mid-length	33	29	–
height of rostrum at mid-length	33.5	29	–
width of premaxillae at rostrum mid-length	27	24	–
distance from rostrum tip to anterior end of palatine	286	253	–
length of upper alveolar row	286(l)/288(r)	264(r)	–
number of upper alveoli per row	40	–	–
distance between last left and right maxillary alveoli	66	60	–
maximum width of dorsal opening of mesorostral groove	10.5	13	11
distance between premaxillae at anterior margin of bony nares	3	5	e4.5
width of rostrum at base	e104	91	104
height of rostrum at base	48	44	–
width of premaxillae at rostrum base	59	47	53.5
width of right premaxilla at rostrum base	24.5	19.5	e24.5
width of left premaxilla at rostrum base	25	21.5	e22
preorbital width	+174	164.5	e182
postorbital width	e182	+161	e196
bizygomatic width	e186	+164	e200
maximum width of premaxillae in facial region	70.5	61	66
width of right premaxillary sac fossa	33	28	–
width of left premaxillary sac fossa	33	31.5	–
orbit length (left)	e57	e54.5	e54
anteroposterior length of temporal fossa (left)	89	–	86
dorsoventral height of temporal fossa	67	e65	e70
maximum width of bony nares	29	27	e27
minimum width across ascending processes of premaxillae	63.5	56	–
maximum width of premaxillae at anterior margin of vertex	66	61	–
maximum width of nasals	49	44.5	–
maximum length of nasals	33	+24	–
length of median suture between nasals	15	e11	–
minimum distance between maxillae across vertex	43	36	e35
minimum distance between temporal crests across occipital shield	78.5	–	77.5
distance between anterior tip of zygomatic process and ventral tip of postglenoid process	59.5	+55	e50
width of mandibular fossa	26	–	–
width of occipital condyles	e74	–	–
left periotic total length	–	–	+24.8
left periotic mediolateral width	–	–	17.8
left periotic dorsoventral thickness	–	–	10.8
length of anterior process of left periotic	–	–	7.3
length of pars cochlearis of left periotic (from anterior margin to anterior margin of fenestra rotunda)	–	–	9.1
dorsoventral thickness of pars cochlearis (from anterior margin to medial margin of internal acoustic meatus)	–	–	8.7
distance between fenestra rotunda and tip of anterior process	–	–	16.8
distance between distal opening of facial canal and tip of anterior process	–	–	12.9
maximum dorsoventral thickness of involucrum of left tympanic bulla (in anterior half)	–	–	8.6