Platygonus sp.

Gasparini, G. M. & Ubilla, M., 2011, Platygonus sp. (Mammalia: Tayassuidae) in Uruguay (Raigón? Formation; Pliocene-early Pleistocene), comments about its distribution and palaeoenvironmental significance in South America, Journal of Natural History 45 (45 - 46), pp. 2855-2870 : 2859-2863

Platygonus sp.

Studied material

Isolated teeth ( PM 4 and pm2) corresponding to a single individual FC-DPV-444 ( Figure 2 ).

Geographic provenance

Near Sauce town, Canelones Department, Uruguay ( Figure 1 ).

Stratigraphic provenance

Raigón? Formation (Pliocene to early Pleistocene). Assignation to this unit is doubtful because it comes from a drill core.

Description

Simple premolars, with two cusps, bunolophodont, mesodont and with a cingulum surrounding the entire tooth, corresponding to a large specimen.

1 The first spelling was actually “ Platigonus ”, but there is sufficient indication that this was a misprint. The name is differently misprinted (Platydonus) in another paper by Le Conte, published almost simultaneously. “ Platygonus is now universally used and may be retained” ( Simpson 1945: 146) (see Mc Kenna and Bell 1997). See also the International Code of Zoological Nomenclature (1999), Articles 32 and 33.

2 According to Mones (1986) Listriodon Von Meyer 1846

3 Proposed as subgenus of Platygonus .

pm2 two-rooted and subtriangular in outline. Crown bears laterally paired major cusps and a low posterior heel. Each principal cusp subconical. Small anteroposteriorly flattened cingulum at anterior base of main cusps. Talonid bears worn central, transversely elongate accessory cuspule encircled by robust posterior cingulum.

PM 4 with three roots, two labial, one lingual. This tooth subquadrate, transverse with only two major cusps anteroposteriorly compressed and almost forming a sharpedged, transverse loph. This tooth wider than long.

Measurements

Measurements are listed in Table 1.

Comments

These isolated teeth have certain diagnostic morphological characters that allow us to determine the material as Platygonus sp. In particular, these are simple premolars with two major cusps, crown morphology is bunolophodont, crown height is mesodont and the enamel cingulum surrounds the entire tooth.

The development of mesodont and bunolophodont cheek teeth in Platygonus differs from the branquiodont and bunodont morphology observed in Tayassu and from the mesodont crown height and bunodont and “zygodont” cheek teeth (bunolophodont cheek teeth with higher and sharper cusps than in typical bunodont forms and fainter crests) observed in Catagonus . Besides this, the enamel cingulum never surrounds the entire tooth in Catagonus and Tayassu species ; it develops on two or three sides (e.g. anterior, labial and posterior) of the teeth.

The crown configuration (presence of two principal cusps) of pm2 is similar to that observed in Tayassu species and in contrast to Catagonus species , which have only one major cusp. The presence of two major cusps on PM 4 and its measurements clearly differ from Catagonus and Tayassu species , which have a molariform PM 4, slightly longer than wide.

Taking into account the dental measurements of the material, it belongs to one of the largest tayassuids among the North American and South American Platygonus considered in the available comparative sample (see Tables 1, 2 and Figure 3 ), especially with regards to the absolute size of PM 4 and width of pm2.

Collection no. Geographical and stratigraphic provenance

FC-DPV-444 Uruguay, Canelones Department, near Sauce town; Raigón?

Formation (Pliocene–early Pleistocene)

UF 57258 USA, Florida, Inglis IA, Citrus; early Irvingtonian

UF 53857 USA, Florida, Bartow Polk

UF 62700 USA, Florida, Haile 21 A, Newberry Quad., Alachua; middle Irvingtonian

UF 66679 USA, Florida, Haile 21 A, Newberry Quad., Alachua; Irvingtonian

UF 66693 USA, Florida, Haile 21 A, Newberry Quad., Alachua; Irvingtonian

UF 62702 USA, Florida, Haile 21 A, Newberry Quad., Alachua; Irvingtonian

UF 66694 USA, Florida, Haile 21 A, Newberry Quad., Alachua; Irvingtonian

UF 18187 USA, Florida, Inglis IA, Citrus

UF 62613 USA, Florida, Haile 21A; late Irvingtonian

UF 221238 USA, Florida , Haile 21 A, Alachua; early Irvingtonian

UF 63924 USA, Florida, Leisey Shell Pit Ruskin Quad., Hillsborough; Irvingtonian

UF 67180 USA, Florida, Leisey Shell Pit Ruskin Quad., Hillsborough; Irvingtonian

UF unknown USA

AMNH27871 USA, Maryland, northwest of Cumberland; early Rancholabrean

AMNH45703 type USA, Missouri, St Louis, Cherokee Cave; Pleistocene

AMNHFLA6-90 USA, Florida, Devil’s Den Mine, Levy; Rancholabrean

AMNH45724 type USA, Missouri, St Louis, Cherokee Cave; Pleistocene

MMP (S) 156 type Argentina, Buenos Aires, Gral. Pueyrredón, southwest Lobería Stream, upper level of Barranca de Los Lobos “Formation”; Marplatan Age , Barrancoloban Subage

MMP (M) 878 Argentina, Buenos Aires, Gral. Pueyrredón, southwest Lobería Stream, upper level of Barranca de Los Lobos “Formation”; Marplatan Age , Barrancoloban Subage

MLP unknown Argentina, Buenos Aires, Gral. Pueyrredón, between Lobería Stream and Punta Vorohué, San Andrés “Formation”; Marplatan Age, Sanandresian Subage

MMP 199 Argentina, Buenos Aires, Gral. Pueyrredón, Barranca de Los Lobos, Chapadmalal “Formation”, layer 9; late Chapadmalalan Age

MACN 19726 Argentina, Buenos Aires, Gral. Pueyrredón, between Lobería Stream and Punta Vorohué, Chapadmalal “Formation”; Marplatan Age, Sanandresian Subage

MMP (M) 246 Argentina, Buenos Aires, Gral. Pueyrredón, Punta San Andrés; Marplatan Age, Vorohuan Subage

MACN 5337 Argentina, Jujuy, Uquía; Marplatan Age

MMP-M 1617 Argentina, Buenos Aires, Bajada Luna Roja, Vorohué; Marplatan Age

MMP 1212 Argentina, Buenos Aires, Gral. Alvarado, Cañada Chapar, Vorohué inferior; Marplatan Age

; Platygonus bicalcaratus ; Platygonus cumberlandensis .

Figures

Figure 1. (A) Fossil record of the genus Platygonus in South America. A, Nariño locality; B, Tarija valley; C, Uquía, Jujuy Province; D, Esquina Blanca, Jujuy Province; E, Buenos Aires city; F, General Pueyrredón county; G, General Alvarado county; H, Canelones Department. (B) Geographical location of the FC-DPV-444. H, Canelones Department.

Figure 2. FC-DPV-444. (A,B) PM4: (A) occlusal view, (B) anterior view; (C,D) pm2: (C) occlusal view, (D) labial view. Scale bar 10 mm.

Figure 3. Bivariate diagram based on PM4 length/width and pm2 length/width of the FC-DPV-444 and comparative samples. FC-DPV-444; Platygonus scagliai -; Platygonus chapadmalensis; Platygonus marplatensis; Platygonus sp. (South America); Platygonus vetus; Platygonus cf. P. vetus; Platygonus compressus; Platygonus sp. (North America)