List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Mammalia
- Cetacea
- Basilosauridae
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Basilosauridae indet.
Cope 1867
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1 specimen | ||||||
| see common names | |||||||
Geography
| Country: | Peru | State/province: | Amazonas | County: | Utcubamba |
| Coordinates: | 5.7° South, 78.4° West (view map) | ||||
| Paleocoordinates: | 8.2° South, 68.7° West | ||||
| Basis of coordinate: | stated in text | ||||
| Geographic resolution: | outcrop |
Stratigraphy
| Formation: | Cajaruro | ||||
| Stratigraphy comments: Cajaruro Formation (late early to early late Eocene, 48.6–37.8 Ma).
From Moreno et al., 2020: Davydenko et al. (2018) described the fossil remains of a basilosaurid, a marine cetacean, from the Cajaruro Formation. Although Davydenko et al. (2018) does not constrain the stratigraphic position of the cetacean‐bearing interval within the Cajaruro Formation, their description corresponds to lacustrine facies in the upper part of the unit. Considering this paleontological evidence, along with the marine nature of the correlative Pozo Formation in the neighboring Santiago, Marañon, and Huallaga basins, limited marine incursions in the lacustrine system ofthe Cajaruro Formation and/or connection to the eastern epicontinen- tal sea are considered plausible. This interpretation is in line with Davydenko et al. (2018), who recognize coastal lagoons as a possible habitat for basilosaurids. The sedimentary deposits corresponding to the Cajaruro Formation have been suggested to be middle to late Eocene in age on the basis of its fossil record and stratigraphic position (Baca Alvarez, 2004; Mourier et al., 1986, 1988). We recovered and dated detrital zircons from sandstones near the base and at intermedi- ate levels of the formation. We calculate MDAs YC2σ (+3) of 49.5 ± 0.3 Ma and 42.8 ± 0.5 Ma for the lower and middle levels, respectively (Samples 146026 and 145314; Figure 4; Table 1). These age estimations are consistent with the fossil age suggested by Mourier et al. (1988) based on the presence of the fossil charo- phytes Nitellopsis suraplana, Maederiella sp., and Chara strobolocarpa that span the early Paleocene to mid- dle Eocene. Based on these constrains and on its stratigraphic position, the Cajaruro Formation is considered to be latest Paleocene to latest Eocene in age |
Lithology and environment
| Primary lithology: | silty claystone |
| Secondary lithology: | siltstone |
| Includes fossils? | Y |
| Includes fossils? | Y |
| Lithology description: The cetacean-bearing formation is composed of white or grayish silt argillites, siltstones, and tuffs at its base, which are welded with coarse- grained sandstones, redeposited tuffs, conglomerate layers with marls and limestones, and layers of pinkish gypsum. The upper horizon is composed of a detrital sequence of shales and brown or gray silt argillites with thin layers of gypsum. | |
| Environment: | marine indet. |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils |
Collection methods and comments
| Reason for describing collection: | general faunal/floral analysis |
| Collection method comments: MUSM, Lima | |
Metadata
| Database number: | 200127 | ||
| Authorizer: | M. Uhen | Enterer: | M. Uhen |
| Modifier: | M. Kouvari | Research group: | vertebrate |
| Created: | 2019-03-18 12:28:25 | Last modified: | 2020-09-14 02:19:38 |
| Access level: | the public | Released: | 2019-03-18 12:28:25 |
| Creative Commons license: | CC BY |
Reference information
Primary reference:
| 47926. | S. Davydenko, M. J. Laime, and P. Gol'din. 2019. The earliest record of a marine mammal (Cetacea: Basilosauridae) from the Eocene of the Amazonia. Journal of Vertebrate Paleontology e1549060 [M. Uhen/M. Uhen/M. Uhen] |