Villa 25 de Mayo (Miocene of Argentina)

Also known as Veinticinco de Mayo

Where: Mendoza, Argentina (34.6° S, 68.6° W: paleocoordinates 34.8° S, 66.4° W)

• coordinate based on nearby landmark

When: Aisol Formation, Huayquerian (9.0 - 6.8 Ma)

• Garrido, et al. 2014: the size and morphology of the MHNSR-PV 1157 refer to Microtragulus catamarcensis known so far for its holotype (MACN 5529) recovered from the Andalhuala Formation, province of Catamarca (Simpson, 1970), whose deposits were attributed to the late Miocene (Huayqueriense; eg, Goin et al. 2000) or Pliocene (Montehermo-sense-Chapadmalalense (Reguero and Candela, 2011). The well-known biochron of M. catamarcensis suggests that: (1) MHNSR-PV 1157 is older than the remains previously recovered from this taxon, or (2) the allocation of the outcrops in the Villa May 25 does not correspond to the Aisol Formation These uncertainties reveal the need to continue the paleontological studies and stratigraphic in the area foresaw establishing regional stratigraphic correlations.

•This collection had a Miocene age assigned. But:

•In preliminary studies, the Aisol Formation was con- sidered early Miocene (probably Santacrucian SALMA; e.g., Groeber 1951; Dessanti 1954, 1956; González Díaz 1972; Núñez 1976) based upon few fossil findings and stratigraphic correlations. Nonetheless, it is also worth mentioning that in one of those preliminary studies, Groeber (1952) suggested that the unit (informally called «Estratos Calchaquíes» by then) was late Miocene, and was included among the «Arauco-Entrerriano» levels. Later studies did not further the debate. Pascual and Odreman-Rivas (1973; see also Pascual and De la Fuente 1993) placed the Aisol Formation in the Miocene, in the temporal interval between the Santacrucian and Friasian SALMAs. It was after the analysis of new fossil findings that Soria (1983) specifically allocated the Aisol Formation to the Friasian s.l. (including Colloncuran, Friasian s.s., and Mayoan, following Bondesio et al. 1980), because of the occurrence of post-Santacrucian and pre- Chasicoan mammals. This hypothesis was also followed by later authors (Sepúlveda et al. 2001, 2007). The analysis of the new fossil material and the strati- graphic control of the findings led to recognize two dif- ferent fosiliferous sections in the profile, with faunal as- semblages of different ages. The LS is probably middle Miocene, as Soria suggested (1983), perhaps Friasian s.s. (older than 15 Ma; Marshall and Salinas 1990) or Collon- curan (15.5-14 Ma; Marshall et al. 1977; Marshall and Salinas 1990), following the Patagonian scheme. Unfor- tunately, there is no consensus about the time span cov- ered by some of the SALMAs, including the Friasian one. Specific studies on age and taxonomic composi- tion are needed before making any comparisons with more distantly located stratigraphic units.

•Three different sections are recognized within the Aisol Formation, with fossil vertebrates in the lower (LS) and middle (MS) sections. According to preliminary results of Forasiepi et al., 2011: Lower Section: Friasian s.s (not used anymore). or Colloncuran and Middle Section: Huayquerian.

•But this collection does not specify whether it refers to the Lower or Middle section but a L. Miocene/Pliocene age is suggested so it must be the Middle section.

Environment/lithology: terrestrial; lithology not reported

Size class: macrofossils

Collection methods: Museo de Historia Natural de San Rafael, San Rafael, Mendoza, Argentina

Primary reference: M. S. de la Fuente. 1992. Las tortugas Chelidae del Terciario superior y Cuaternario del territorio argentino. Ameghiniana 29(3):211-229 [E. Vlachos/E. Vlachos]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 189510: authorized by Evangelos Vlachos, entered by Evangelos Vlachos on 24.10.2017, edited by Miranta Kouvari

Creative Commons license: CC BY (attribution)

Taxonomic list

Mammalia
 Polydolopimorphia - Argyrolagidae
Argyrolagidae indet.1 Ameghino 1904 metatherian
MHNSR-PV 1157
Reptilia
 Testudines - Chelidae
Phrynops indet.2 Wagler 1830 sideneck turtle
MHNSR-PV 048, internal mold and part of the shell