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Prosqualodon australis

Mammalia - Ungulata

Prosqualodon australis was named by Lydekker (1894) [specimen number not listed in Lydekker. Kellogg (1923) states that the type specimen i sin the Museo de La Plata, Argentina]. Its type specimen is MLP 5-9, a skull, and it is a 3D body fossil. Its type locality is Cerro del Castillo, Trelew, which is in an Aquitanian/Burdigalian shallow subtidal sandstone in the Gaiman Formation of Argentina. It is the type species of Prosqualodon.

  • Proinia patagonica was named by True (1909). Its type specimen is YPM-PU 15459, a partial skull, and it is a 3D body fossil. Its type locality is Darwin Station, which is in a Miocene marine horizon in the Monte Leon Formation of Argentina.

    It was considered a nomen dubium by de Muizon (1988); it was synonymized subjectively with Prosqualodon australis by Cozzuol (2010).
Synonymy list
YearName and author
1894Prosqualodon australis Lydekker
1898Prosqualodon australis Trouessart p. 1011
1901Prosqualodon australis Ameghino p. 80
1904Prosqualodon australis Trouessart p. 754
1909Proinia patagonica True p. 441 figs. Plate 43, Fig. 1
1914Prosqualodon australe Abel p. 220
1923Prosqualodon australis Kellogg p. 7
1925Prosqualodon australis Zittel p. 86
1942Proinia patagonica Kellogg p. 447
1981Prosqualodon australis Fordyce p. 1041
1982Prosqualodon australis Sanders et al. p. H120
2019Prosqualodon australis Gaetán et al. p. 4

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phylumChordataHaeckel 1847
subclassDipnotetrapodomorpha(Nelson 2006)
orderUngulata(Linnaeus 1766)

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

C. M. Gaetán et al. 2019Prosqualodon australis is a medium- sized odontocete (estimated total body length is 2–3 m long) characterized by the following combination of charac- ters: presence of an antorbital process of the maxilla with a very extended anterior blunt projection, lateral to the an- torbital notch and with a lateral concave margin; a well-de- veloped heterodontia with a rugose tooth enamel forming minute denticles; two dorsal infraorbital foramina; nasals as the highest bone on the vertex and nuchal crest below the frontals. Prosqualodon australis differs from Prosqualo- don davidis in the presence of a ventrally triangular postgle- noid process instead of a squared one, in having a zygomatic process of the squamosal with a flat or almost flat ventral surface and in the more developed antorbital process of the maxilla. It also differs from Prosqualodon davidis and Squalodon calvertensis in the lack of the maxillary intrusion between premaxillae at the narial region. Prosqualodon aus- tralis differs from Squalodon calvertensis in having a more concave posterior sinus, frontals posteriorly wider than nasals, a triangular postorbital process of the frontal, the absence of entocingulum, occipital condyles without pedicels, lacrimal and jugal in the antorbital notch, and in the absence of premaxillary notch. It differs from Otekaikea Tanaka and Fordyce, 2014 in lacking the intra-premaxillary foramen and from Waipatia Fordyce, 1994 in having a ven- trally triangular postglenoid process. Unlike Squalodelphis Dal Piaz, 1917, Prosqualodon australis has a lateral margin of the rostrum concave (anterior to the maxillary flange) instead of straight, premaxillae separated by the mesorostral canal in all rostral extension, and in having a ventrally straight zygomatic process. Prosqualodon australis differs from Notocetus Moreno, 1892, Platanista Wagler, 1830, and Zarhachis Cope, 1868 in the absence of a posterior dorsal infraorbital foramen near the posterior end of the premaxilla, in having a less developed vertex asymmetry, in having occipital condyles without pedicels, frontals posteriorly wider than the nasals and heterodont teeth. With Platanista and Zarhachis differs in lacking rostral asymmetry, in having a zygomatic process ventrally straight instead of convex, and in lacking a longitudinal groove on the posterior apex of the maxilla. It also differs from Platanista in having a well- developed postglenoid process of the squamosal bone, a proportionally wider rostrum, an external occipital crest, contact between maxilla and supraoccipital, in lacking parietals expose at the dorsal surface of the vertex and in lacking contact between orbitosphenoid and lacrimal. Prosqualodon australis differs from Zarhachis in having nodular enamel on the teeth, nasals higher than frontals, a semicircular nuchal crest in posterior view and a smaller tympanosquamosal recess. Prosqualodon australis also differs from Notocetus in having transversally wider premaxillae at the rostrum, in the conical shape of the anterior end of the zygomatic process of the squamosal, in the al- most straight ventral border of the aforementioned process, in having a semicircular nuchal crest (in posterior view), in having an external occipital crest and longer teeth crowns (proportionally).