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Vereda Llanitos (Cretaceous to of Colombia)

Where: Boyaca, Colombia (5.6° N, 73.5° W: paleocoordinates 3.5° N, 42.2° W)

When: Arcillolitas abigarradas Member (Paja Formation), Early/Lower Barremian to Early/Lower Barremian (130.0 - 112.6 Ma)

• Two members of the Paja Formation are recognized, the Arcillolitas abigarradas (Barremian–Aptian; 480 m thick) and Arcillolitas con nodulos huecos (Aptian; 80 m thick; Fig. 1; Etayo-Serna 1968; Guerrero 2002a, b). Macrofossils are for the most part preserved in calcareous concretions; the part of this formation richest in fossil vertebrates appears to be the Barremian–Aptian aged Arcillolitas abigarradas Member (Etayo-Serna 1968). The Arcillolitas abigarradas forms extensive natural outcrops in the area around Villa de Leyva (Fig. 1). Ammonites are exceptionally abundant and three-dimensionally preserved in this region. Thus, relative age is constrained primarily by ammonite biostratigraphy, relying heavily on the zonation scheme proposed by Etayo-Serna (1968) and refined by subsequent authors (Patarroyo 2000; Hoedemaeker 2004). Correlation between Colombian (Caribbean Subprovince, Tethyan Realm) and European (Mediterranean Subprovince, Tethyan Realm) ammonite zones has been attempted based on genera and even species shared between the two regions (Patarroyo 2000; Hoedemaeker 2004; Kakabadze et al. 2004). These include species of Nicklesia, Pulchellia, Heinzia, Pseudohaploceras, Colchidites, Cheloniceras, Acanthohopclites, Colombiceras and Dufrenoyia, among others (Etayo-Serna 1968; Patarroyo 2000; Hoedemaeker 2004; Kakabadze et al. 2004).

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified, nodular shale and lithified limestone

• The Paja Formation consists of intercalated black shales and limestones of Early Cretaceous age (Hauterivian– Aptian) deposited in a quiet back-arc basin (Hoedemaeker 2004; Campos-Alvarez and Roser 2007). Environmental interpretations range from intertidal (Forero-Onofre and Sarmiento-Rojas 1985; Hoedemaeker 2004), to shallow marine inner to middle shelf (Guerrero 2002a; Caceres et al. 2003; Campos-Alvarez and Roser 2007). The latter interpretation is more consistent with the abundant wellpreserved vertebrate fossils and black shale deposition.

Size class: macrofossils

Primary reference: E. E. Maxwell, D. Dick, S. Padilla and M. L. Parra. 2015. A new ophthalmosaurid ichthyosaur from the Early Cretaceous of Colombia. Papers in Palaeontology [V. Fischer/V. Fischer] more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 175725: authorized by Valentin Fischer, entered by Valentin Fischer on 05.01.2016

Creative Commons license: CC BY (attribution)