Biscarri, Isona (Cretaceous of Spain)

Where: Cataluña, Spain (42.1° N, 1.1° E: paleocoordinates 34.1° N, 0.9° E)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: La Posa Formation (Tremp Group), Early/Lower Maastrichtian (70.6 - 66.0 Ma)

• La Posa Grey Marls = "lower Member" of Tremp Formation. Layer with eggs is at the top of an 80 m thick succession of gray marls, shales, lignites, and limestones within this member

•La Posa Fm. = early Maastrichtian (Fondevilla et al. 2019)

• bed-level stratigraphic resolution

Environment/lithology: lagoonal or restricted shallow subtidal; lithified, burrowed, bioturbated, pyritic, gray marl

• "the profile was within the phreatic nape, below the vadose zone. These features indicate water-saturated sediments in a reducing coastal environment, from peritidal swamp (lignites and limestones) to tidal flats (grey marls)...water-logged tidal flat sediments from a perilagoonal environment...the nest was flooded and covered with mud and subsequently perforated by the growth of plant roots associated to the prograding salt-marsh."
• "a homogeneous, grey-coloured marl with iron-encrusted root casts (rhizoliths)...the eggs contain the same types of grey marl that underlie them, and contain framboidal pyrite encrusting the interior side of the eggshells. The marls bear iron-reduced colours and locally contain bioturbation structures (burrows) preserved as siderite concretions that are diagenetic products of the first-formed hydroxides. Leaching features, nodulization or mottling (marmorization) are absent."

Size classes: macrofossils, mesofossils

Preservation: trace

Collection methods: surface (in situ),

Primary reference: M. Vianey-Liaud and N. López-Martínez. 1997. Late Cretaceous dinosaur eggshells from the Tremp basin, southern Pyrenees, Lleida, Spain. Journal of Paleontology 71(6):1157-1171 [M. Carrano/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 13331: authorized by Matthew Carrano, entered by Matthew Carrano on 26.02.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Reptilia
 Ornithischia - Nodosauridae
Nodosauridae indet.
Nodosauridae indet. Marsh 1890 ankylosaur
teeth
 Saurischia - Titanosauridae
Megaloolithus siruguei
Megaloolithus siruguei Vianey-Liaud et al. 1994 titanosaurid