Crustacean microcoprolites from the Upper Jurassic - Lower Cretaceous of the Neuquén basin, Argentina: Systematic and biostratigraphic implications

KIETZMANN, D.A.; BLAU, J.; FERNANDEZ, D.E.; PALMA, R.M.

ACTA PALAEONTOLOGICA POLONICA

INST PALEOBIOLOGII PAN

Lugar: Warszawa; Año: 2010 vol. 55 p. 277 - 284

0567-7920

As a result of a microfacial study in the outer and middle ramp deposits of the Vaca Muerta Formation (lower Tithonian ? upper Valanginian), four ichnotaxa of crustacean microcoprolites are described: Palaxius azulensis Kietzmann isp. nov., Palaxius caracuraensis Kietzmann isp. nov., Helicerina isp. A aff. Helicerina siciliana and Helicerina isp. B. They represent one of the first records of crustacean microcoprolites for the Neuquén Basin and Argentina. Helicerina represents the first mention for the Upper Jurassic and Lower Cretaceous of South America. It can be inferred that Palaxius ichnospecies were produced by callianassids, while Helicerina ichnospecies could be produced by decapods of Mecochiridae, Erymidae and/or Nephropidae affinity. Two assemblages of crustacean microcoprolites are recognised, a middle Tithonian to lower Berriasian Palaxius-dominated assemblage and an early to late Valanginian Helicerina-dominated assemblage.