Cerro del Castillo, Trelew (Miocene to of Argentina)

Where: Chubut, Argentina (43.3° S, 65.3° W: paleocoordinates 44.0° S, 59.2° W)

• coordinate estimated from map

When: Gaiman Formation, Aquitanian to Aquitanian (23.0 - 16.0 Ma)

• formacion patagonica marina; early Miocene date form Fordyce (2002); In the area of the type locality of M. parvus, the lower part of Gaiman Formation overlies the continental Sarmiento Formation, which contains a mammal fauna correlating with the Colhuehuapian South American Land Mammal Age [51,52]. The latter was dated to 19.8-20.9 Ma, based on 40Ar/39Ar dating [53], thus providing a maximum age of ca. 20 Ma (earliest Burdigalian) for the lower part of the Gaiman Formation in this area. Since virtually all vertebrate material recovered so far originated from the lowermost levels of the Gaiman Formation, close to its contact with the Sarmiento Formation (Cozzuol 2010, pers. comm.), the age of Morenocetus is here assumed to be early Burdigalian. (Fordyce & Marx, 2013)

•Both MLP 5-11 and 5-11 were originally reported to have come from the Patagonian Marine Formation [40]. The latter corresponds to the partially correlated Monte León and Gaiman formations, exposed in Santa Cruz (e.g. Garn Bajo de San Juan) and the lower Chubut river valley near Trelew (e.g. at Bryn Gwyn/ Loma Blanca), respectively [42]. In the area around Trelew, the lower part of Gaiman Formation overlies the continental Sarmiento Formation, which contains a mammal fauna correlating with the Colhuehuapian South American Land Mammal Age [43, 45]. The latter has been 40Ar/39Ar dated to 20.9– 19.8 Ma [46], thus providing a maximum age of 19.8 Ma (earliest Burdigalian) for the lower part of the Gaiman Formation in this area. Since virtually all vertebrate material recovered so far originated from the lowermost levels of the Gaiman Formation, close to its contact with the Sarmiento Formation [Cozzuol 2010, pers. comm.], an early Burdigalian age (19.8–18.2 Ma) is here assumed for M. parvus. (Marx & Fordyce, 2015)

• formation-level stratigraphic resolution

Environment/lithology: shallow subtidal; argillaceous sandstone

• The holotype of A. moreni was found in “a mixture of sand and clay, including a stratum of sand capped by volcanic sand.” ([39]:1). The original description further explained that ”an apparently contemporaneous bed in Santa Cruz, also containing cetacean bones, has yielded oysters of an extinct species (Ostrea patagonica), and one skull from Chubut has one of the same oysters attached” [39: 1-2]. MLP 5-14 was later discovered at the same locality, described as “Castillo, frente a Trelew, Chubut” [40: 369], and reported to have come from the Patagonian Marine Formation (“formación patagónica marina”, [40: 364]).

•The Patagonian Marine Formation corresponds to the partially correlated Monte León and Gaiman formations, exposed in Santa Cruz (e.g. Garn Bajo de San Juan) and the lower Chubut river valley near Trelew (e.g. at Bryn Gwyn/ Loma Blanca), respectively [42]. The Gaiman Formation consists of layers of marine sandstones and mudstones, as well as tuffs and tuffaceous sandstones. In addition, the lower part also contains occasional thin layers of Ostrea and bones of marine vertebrates [43]. Thus, the portion of the Gaiman Formation exposed near Trelew provides a likely match for the unit that yielded A. moreni [39, 40, 44].

•11

•In the area around Trelew, the lower part of Gaiman Formation overlies the continental Sarmiento Formation, which contains a mammal fauna correlating with the Colhuehuapian South American Land Mammal Age [43, 45]. The latter has been 40Ar/39Ar dated to 20.9– 19.8 Ma [46], thus providing a maximum age of 19.8 Ma (earliest Burdigalian) for the lower part of the Gaiman Formation in this area. Since virtually all vertebrate material recovered so far originated from the lowermost levels of the Gaiman Formation, close to its contact with the Sarmiento Formation [Cozzuol 2010, pers. comm.], an early Burdigalian age (19.8–18.2 Ma) is here assumed for A. moreni. (Marx & Fordyce, 2015)

•Shows a shallow, storm-dominated marine environment with significant sea level oscillations.

• a mixture of sand and clay, including a stratum of sand capped by volcanic sand

Size class: macrofossils

Preservation: original phosphate

Primary reference: A. Cabrera. 1926. Cetaceos fossiles del Museo de La Plata. Revista del Museo de La Plata 29:363-411 [M. Uhen/M. Uhen/M. Uhen]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 47303: authorized by Mark Uhen, entered by Mark Uhen on 22.02.2005

Creative Commons license: CC BY (attribution)

Taxonomic list

Aves
 Sphenisciformes -
"Chubutodyptes biloculata n. gen. n. sp." = Palaeospheniscus bilocular4, "Palaeospheniscus patagonicus n. sp." = Palaeospheniscus patagonicus2, "Palaeospheniscus interruptus" = Palaeospheniscus patagonicus3, "Palaeospheniscus affinis" = Palaeospheniscus patagonicus3, "Palaeospheniscus menzbieri n. sp." = Palaeospheniscus patagonicus2, "Palaeospheniscus gracilis" = Palaeospheniscus gracilis3, "Neculus rothi" = Palaeospheniscus gracilis3, "Palaeospheniscus medianus" = Palaeospheniscus gracilis3, "Palaeospheniscus bergi n. sp." = Palaeospheniscus bergi2, "Palaeospheniscus rothi" = Palaeospheniscus bergi3
"Chubutodyptes biloculata n. gen. n. sp." = Palaeospheniscus bilocular4 Simpson 1970 penguin
"Palaeospheniscus patagonicus n. sp." = Palaeospheniscus patagonicus2 Moreno and Mercerat 1891 penguin
"Palaeospheniscus interruptus" = Palaeospheniscus patagonicus3 Moreno and Mercerat 1891 penguin
"Palaeospheniscus affinis" = Palaeospheniscus patagonicus3 Moreno and Mercerat 1891 penguin
"Palaeospheniscus menzbieri n. sp." = Palaeospheniscus patagonicus2 Moreno and Mercerat 1891 penguin
"Palaeospheniscus gracilis" = Palaeospheniscus gracilis3 Ameghino 1899 penguin
"Neculus rothi" = Palaeospheniscus gracilis3 Ameghino 1899 penguin
"Palaeospheniscus medianus" = Palaeospheniscus gracilis3 Ameghino 1899 penguin
"Palaeospheniscus bergi n. sp." = Palaeospheniscus bergi2 Moreno and Mercerat 1891 penguin
"Palaeospheniscus rothi" = Palaeospheniscus bergi3 Moreno and Mercerat 1891 penguin
 Sphenisciformes - Spheniscidae
"Palaeospheniscus robustus" = Paraptenodytes robustus3, "Treleudytes crassus" = Paraptenodytes robustus3, "Palaeospheniscus antarcticus n. gen. n. sp." = Paraptenodytes antarcticus3
"Palaeospheniscus robustus" = Paraptenodytes robustus3 Ameghino 1894 penguin
"Treleudytes crassus" = Paraptenodytes robustus3 Ameghino 1894 penguin
"Palaeospheniscus antarcticus n. gen. n. sp." = Paraptenodytes antarcticus3 Moreno and Mercerat 1891 penguin
Mammalia
 Mysticeti - Balaenidae
Morenocetus parvus n. gen. n. sp.
Morenocetus parvus n. gen. n. sp. Cabrera 1926 right whale
 Balaenopteroidea -
"Cetotherium moreni n. sp." = Aglaocetus moreni1
"Cetotherium moreni n. sp." = Aglaocetus moreni1 Lydekker 1894 whale
 Balaenopteroidea - Balaenopteridae
Plesiocetus dyticus n. sp. Cabrera 1926 rorqual
 Odontoceti - Squalodontidae
Phoberodon arctirostris n. gen. n. sp.
Phoberodon arctirostris n. gen. n. sp. Cabrera 1926 toothed whale