Pomata Ayte (Neogene to of Bolivia)

Also known as Formacion Mauri

Where: Oruro, Bolivia (18.3° S, 67.9° W: paleocoordinates 18.5° S, 66.8° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Umala Formation, Montehermosan to Montehermosan (6.8 - 3.0 Ma)

• Saint-Andre et al 2010: Ce gisement correspond à la Formation Mauri qui repose sur la Formation Rosa Pata d’âge huayquérien, et plus particulièrement sur le faciès terminal de cette dernière, le « Conglomérat Pomata » (Marshall & Sempéré 1991).

•Cette « Formation Mauri » est probablement diff érente de la formation homonyme de l’Oligocène et du Miocène de la Cordillère Occidentale et de l’Ouest de l’Altiplano et représente un équivalent stratigraphique de la Formation Umala. La base de cette dernière peut être datée grâce à la présence de la Toba 76 et son sommet grâce au « tuf volcanique Ayo Ayo », daté à 2,8 Ma.

•Boscaini et al 2018: a horizon bounded below by Toba 76 and above by another volcanic level, the 2.8 Ma Ayo Ayo tuff ; its age is Montehermosan- Chapadmalalan (early and middle Pliocene).

•The faunal composition is consistent with an earliest Pliocene age (Montehermosan; Hoffstetter et al., 1972; Marshall et al., 1983; Hoffstetter, 1986; Marshall & Sempéré, 1991; Saint-André, 1994; Pujos et al., 2016). Lithostratigraphically, it belongs to the Umala Formation, which lies above the Totora and Pomata Formations. Five metres above the base of the sec- tion, ‘Toba 76’ is recovered. The fossil remains from the Pomata-Ayte locality were found above this tuff, in the basal ~60 m deposits of the Pliocene–Pleistocene Umala Formation (Saint-André et al., 2010).

•Pujos, et al. 2016: This fauna was collected from the Umala Formation, which lies above the Totora and Pomata Forma- tions (St-Andr?e, 1994). The fossiliferous levels occur approximately 100 m above a tuff that corresponds to the ‘Toba 76’ according to St-Andr?e (1994). This tuffaceous level was dated by Marshall et al. (1983), 5.97 ? 0.4 Ma, which corresponds to the Montehermosan SALMA (latest Miocene/early Pliocene).

•Note: this collection had a Mauri or Umala formation assigned. From Everden et al., 1977: Area of Curahuara de Carangas: The base of the Mauri strata at Curahuara de Carangas (5.9 m.y., I E) coincides in age approximately with the age of the "76" tuff (5.4 m.y., I C) on the Desaguadero River. While the base of the Mauri is clearly unconformable at Curahuara, it becomes conformable to the northeast. The ignimbritic tuffs and lavas that constitute the Mauri Formation at Curahuara pass into subaqueous sediments in the same direction, and when the discordance disappears, these sediments form an integral part of the Corocoro Group (upper Rosa Pata Formation). The discordance appears anew to the northeast of Callapa where it marks the base of the Umala Formation of Meyer and Murillo (1961). The basal tuff of this latter formation yielded a K-Ar age of 5.5 m.y. (I D), proving that the lower strata of the Umala Formation are equivalent to those of the Mauri at Curahuara (Hemphillian).

•We refer this collection to the Umala formation, following the latest papers.

Environment/lithology: terrestrial; lithology not reported and tuff

• Pujos, et al. 2016: The fossiliferous levels occur approximately 100 m above a tuff that corresponds to the ‘Toba 76’ according to St-Andr?e (1994).

Size classes: macrofossils, mesofossils

Collected by P.-A. Saint-André, F. Pujos in 1989-1990, 2000 & 2012 and 2015

• P.-A. Saint-André collected specimens in 1989-1990 and published them in his thesis in 1994 and F. Pujos revisited some of the same localities in 2000 for his thesis. Results are presented in this paper.

•Pujos, et al. 2016: A revision of the collection of the MNHN-Bol in La Paz (Bolivia) and preparation in 2013 and 2015 of the newly discovered specimens during the 2012 and 2015 field campaigns in the Montehermosan SALMA of Pomata-Ayte resulted in the identification of the new genus/species of this paper.

Primary reference: L. G. Marshall and T. Sempere. 1991. The Eocene to Pleistocene vertebrates of Bolivia and their stratigraphic context: a review. In R. Suárez-Soruco (ed.), Fósiles y Facies de Bolivia - Vol. 1 Vertebrados (Revista Ténica de YPFB) 12(3-4):631-652 [D. Croft/D. Weinstein/S. Bruning]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 70643: authorized by Darin Croft, entered by Deborah Weinstein on 01.04.2007, edited by Miranta Kouvari

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Mammalia
 Placentalia -
Rodentia indet.1 Bowdich 1821 rodent
 Panameriungulata - Macraucheniidae
Macrauchenia sp.1 Owen 1838 placental
cf. Promacrauchenia sp. Ameghino 1904 placental
 Cingulata -
Cingulata indet.1 Illiger 1811 edentate
 Cingulata - Pampatheriidae
Plaina sp.1 Castellanos 1927 edentate
 Megatherioidea - Megatheriidae
Megatherium (Megatherium) altiplanicum1 Saint-Andre and De Iuliis 2001 edentate
 Megatherioidea - Nothrotheriidae
Aymaratherium jeani n. gen. n. sp.2
Aymaratherium jeani n. gen. n. sp.2 Pujos et al. 2016 edentate
MNHN-Bol-V 008954
  - Mylodontidae
Mylodontidae indet. Ameghino 1889 edentate
Simomylodon uccasamamensis3 Saint-André et al. 2010 edentate
 Notoungulata - Toxodontidae
Posnanskytherium desaguaderoi Liendo Lazarte 1943 notoungulate
Posnanskytherium cf. viscachanense1 Saint-André 1999 notoungulate