Bahia de Guayacan: Zanclean, Chile

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Mammalia - Cetacea - Balaenopteridae
Megaptera hubachi n. sp. Dathe 1983
1 specimen
(1 measurement)
Bivalvia - Ostreida - Ostreidae
Ostrea sp. Linnaeus 1758
Thecostraca - Balanomorpha - Balanidae
Balanus sp. Da Costa 1778
see common names

Geography
Country:Chile State/province:Coquimbo
Coordinates: 30.0° South, 71.4° West (view map)
Paleocoordinates:30.1° South, 70.3° West
Basis of coordinate:estimated from map
Time
Period:Neogene Epoch:Pliocene
Stage:Zanclean 10 m.y. bin:Cenozoic 6
Key time interval:Zanclean
Age range of interval:5.33300 - 3.60000 m.y. ago
Age estimate:5.3 to 3.6 Ma (other)
Stratigraphy
Formation:Coquimbo
Stratigraphy comments: middle Miocene?, Demere et al. (2005) questionably assign this collection to the Piacenzian, while Dathe (1983) had called it lower Pliocene

In his original description, Dathe [155] did not specify the formation that has yielded the specimen, but stated that the fossil had been found at the western end of the “Bahia de Guayacan”, southwest of Coquimbo. He furthermore speculated that the fossil had come from a sandstone of Early Pliocene age, although he could not exclude the possibility of a Middle Miocene age. Dathe‟s figure of the type locality [155: fig. 10] shows primarily the Bay of Tongoy, which is dominated by exposures of the Miocene–Pliocene Coquimbo Formation [156, 157]. The latter is divided into 16 lithostratigraphic units, 5 of which (units 3, 4 and 11–13) have yielded cetaceans remains [156, 158]. Of the latter, only units 4 and 11– 13 contain sandstone, with only unit 11 being dominated by this lithology. Strontium dating and biostratigraphic evidence place units 3 and 4 in the Tortonian (11.9–11.2 Ma), and thus make them much older than the Early Pliocene age suggested by Dathe [155]. By contrast, units 11–13 have been dated to the earliest Pliocene based on biostratigraphic grounds, as well as Sr dates of 5.2 ± 0.7 Ma for the base of unit 12, 4.9 ± 0.7 Ma 2 m above the base ofunit 12, and 2.2 ± 0.5 Ma 6 m below the top of unit 14 (inferred mean ages for units 12 and 13 are 5.0 and 4.3 Ma, respectively) [156]. Considering the coincidence of (i) the occurrence of numerous cetacean fossils in units of the correct lithology and age; and (ii) the broad exposure of these units in the type area of “M. hubachi”, we suggest that the holotype of this species was recovered from the upper, Early Pliocene portion of the Coquimbo Formation. As a result, we follow Dathe [155] in assigning an Early Pliocene (Zanclean, 5.3–3.6 Ma) age to the holotype. Note, however, that Deméré et al. [59] suggested a Piacenzian (3.6–2.6 Ma) age for this specimen. (Marx & Fordyce, 2015)
Lithology and environment
Primary lithology: not reported
Environment:slope
Geology comments: scarp-controlled rocky shoreline to upper continental slope
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Associated major elements:all
Collection methods and comments
Reason for describing collection:taxonomic analysis
Metadata
Database number:56460
Authorizer:M. Uhen Enterer:M. Uhen
Modifier:B. Shipps Research group:vertebrate
Created:2005-11-18 13:30:46 Last modified:2017-05-23 16:34:15
Access level:the public Released:2005-11-18 13:30:46
Creative Commons license:CC BY
Reference information

Primary reference:
15202. F. Dathe. 1983. Megaptera hubachi n. sp., ein fossiler Bartenwal aus marinen Sandsteinschichten des tieferen Pliozaens Chiles. Zeitschrift fuer Geologische Wissenschaften 11(7):813-848 [M. Uhen/M. Uhen/M. Uhen]

Secondary references:

15521 T. A. Deméré, A. Berta, and M. R. McGowen. 2005. The taxonomic and evolutionary history of modern balaenopteroid mysticetes. Journal of Mammalian Evolution 12(1/2):99-143 [M. Uhen/M. Uhen/M. Uhen]
55050 F. G. Marx and R. E. Fordyce. 2015. Baleen boom and bust: a synthesis of mysticete phylogeny, diversity and disparity. Royal Society Open Science 2:140434 [M. Uhen/M. Uhen]