Cerros Bayos (Paleocene of Argentina)

Where: La Pampa, Argentina (37.7° S, 67.5° W: paleocoordinates 40.2° S, 55.9° W)

• outcrop-level geographic resolution

When: PN1 nannofossil zone, Roca Formation, Danian (66.0 - 61.6 Ma)

• material from "two pelitic horizons located 2.5 and 13.5 meters below the base of the oyster bioherms". PJW: PN1 probably should be NP1

• group of beds-level stratigraphic resolution

Environment/lithology: deep subtidal ramp; poorly lithified, yellow marl

• "distal platform environment at the base to lagoonal facies toward the top" of section; fossils are from lower half; on p. 6 the taxonomic association is said to "indicate a low energy pelitic sublittoral environment." Fossils are shown as being from a mudstone in section, presumably meaning a lime mudstone because formational lithology is "carbonates". Section consists of greenish marls intercalated with thin coquinas that are lenticular and have planar or erosive lower contacts. The coquinas suggest storm deposits, indicating a deep subtidal environment.
• yellowish-whitish marine carbonates

Size class: macrofossils

Primary reference: R. M. Feldmann, S. Casadío, L. Chirino-Galvez and M. Aguirre-Urreta. 1995. Fossil decapod crustaceans from the Jaguel and Roca Formations (Maastrichtian-Danian) of the Neuquen Basin, Argentina. Journal of Paleontology 69(5 II):1-22 [J. Alroy/J. Alroy/F. Aspromonte]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 5160: authorized by John Alroy, entered by John Alroy on 01.09.1999, edited by Philip Mannion, Matthew Clapham, Evangelos Vlachos and Franco Aspromonte

Creative Commons license: CC BY (attribution)

Taxonomic list

• forams studied by Leanza and Hugo 1985, nannofossils by Casadio and Concheyro 1992; only one nannofossil species is mentioned
unclassified
  -
Selachia indet.
see p. 6
Foraminifera
 Foraminiferida -
"Foraminiferida indet." = Foraminifera
"Foraminiferida indet." = Foraminifera Eichwald 1830 foram
see p.
Coccolithophyceae
  -
Malacostraca
 Decapoda - Callianassidae
"Callianassa burckhardti" = Eucalliax burckhardti
"Callianassa burckhardti" = Eucalliax burckhardti Bohm 1911 decapod
GHUNLPam 7043
 Decapoda - Ctenochelidae
Ctenocheles sp. Kishinouye 1926 decapod
GHUNLPam 7034-7036, 7044
 Decapoda - Tumidocarcinidae
Xanthilites gerthi Glaessner 1930 crab
GHUNLPam 7019
Lobonotus lobulata Feldmann et al. 1995 crab
 Decapoda - Nephropidae
Hoploparia cf. arbei Aguire-Urreta 1989 clawed lobster
GHUNLPam 7029-7031
Bivalvia
 Ostreida - Pinnidae
 Ostreida - Gryphaeidae
Gryphaeostrea callophyla1 Ihering 1903 oyster
Pycnodonte (Phygraea) sarmientoi n. sp.1 Casadio 1998 oyster
GHUNLPam 6012, holotype
Pycnodonte (Phygraea) burckhardti1 Bohm 1903 oyster
GHUNLPam 1223 al1241, 4830, 4877 al 4878 y 4891 al 4893.
 Ostreida - Ostreidae
 Pectinida - Pectinoidae
 Carditida - Carditidae
Venericardia ameghinorum Ihering 1907 clam
 Cardiida - Veneridae
 Nuculida - Nuculidae
"Nucula (Leionucula) dynastes" = Leionucula
"Nucula (Leionucula) dynastes" = Leionucula nut clam
N. (Leionucula)
 Nuculanida - Malletiidae
Neilo cf. ornata Sowerby 1846 clam
Gastropoda
 Cerithioidea - Turritellidae
Cephalopoda
 Nautilida - Nautilidae
Eutrephoceras sp.2 Hyatt 1894 nautiloid
GHUNLPam 1503 and 1948
 Nautilida - Hercoglossidae
Hercoglossa aff. walteri2 Miller 1947 nautiloid
GHUNLPam 2521 and 4980
Hercoglossa romeroi2 Ihering 1903 nautiloid
GHUNLPam 2500-2520, 4835-4837
Reptilia
 Testudines - Pancheloniidae
"Pampaemys meriodionalis n. gen. n. sp." = Euclastes meridionalis3
"Pampaemys meriodionalis n. gen. n. sp." = Euclastes meridionalis3 de la Fuente and Casadio 2000 turtle
GHUNLPam 19137 - holotype (posteromedial skull fragment)
Echinoidea
 Calycina - Phymosomatidae
Gauthieria menuthiae4 Lambert and Thiery 1911 sea urchin
GHUNLPam 22004
 Spatangoida - Micrasteridae
Diplodetus nutrix4 Boule 1899 heart urchin
GHUNLPam22016–22019 and 22021
 Spatangoida - Hemiasteridae
"Hemiaster hawkinsi" = Hemiaster stella4
"Hemiaster hawkinsi" = Hemiaster stella4 Morton 1830 heart urchin
GHUNLPam22023–22038
 Spatangoida - Schizasteridae
Schizaster sp. Agassiz 1835 heart urchin
see p. 6; possibly only present at General Roca
Paraster joannisboehmi4 Parma and Casadío 2005 heart urchin
CPBA14387, PMOZ3316, PMOZ3344, PMOZ3354, GHUNLPam22052–22065, GHUNLPam22076– 22145, GHUNLPam22149–22150
 Irregularia - Nucleolitidae
Pygopistes parrasae4 Parma and Casadío 2005 sea urchin
GHUNLPam 22009–22014
Psilonichnus
  -
 Ichnofossils -
Thalassinoides sp. Ehrenberg 1944