south side of the Quebrada La Pola, Eastern flank of Sierra de Villicum (Ordovician of Argentina)

Where: San Juan, Argentina (31.3° S, 68.5° W: paleocoordinates 33.8° S, 134.5° W)

• outcrop-level geographic resolution

When: Climacograptus bicornis graptolite zone, Upper Member (La Cantera Formation), Caradoc (458.4 - 449.5 Ma)

• Villas (1995) notes that the clasts containing fossils probably originated from the underlying La Cantera formation. The upper half is Climacograptus bicornis zone, the lower half is Hustedograptus teretiusculus zone.

• formation-level stratigraphic resolution

Environment/lithology: marine; pebbly conglomerate

• "Fossils described in this paper come from pebbles of the upper part of the lower diamictite member of the Don Braulio Fm. Clasts consist of sandstones, limestones, quatzites, quartz, and volcanic rocks, some of them being striated and facetted. This succession is interpretted as glacimarine in origin and is synchronous with the Late Ashgillian world-wide glaciation event."
• Fossils described come from the upper part of the lower member of the Don Braulio Fm. The lower member (8-12 m) is composed of pebbly mudstones capped by channelized conglomerates. This succession is interpretted as a diamictite. Studied fossils have come from coquinites in the diamictite.

Size classes: macrofossils, mesofossils

Preservation: cast

Collection methods: chemical,

• "In order to enhance exposure of teeth and muscle scars, shells were dissolved with hydrochloric acid (10%).

Primary reference: T. M. Sanchez. 1999. New late Ordovician (Early Caradoc) Bivalves from the Sierra De Villicum (Argentine Precordillera). Journal of Paleontology 73(1):66-76 [A. Miller/R. Krause/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 13513: authorized by Arnold Miller, entered by Rich Krause on 10.04.2002, edited by Pete Wagner

Creative Commons license: CC BY (attribution)

Taxonomic list

Pterobranchia
 Graptoloidea - Dicranograptidae
Dicranograptus aff. ramosus Hall 1847 graptolite
Bivalvia
 Actinodontida - Cycloconchidae
Poladonta sanjuanina Sánchez et al. 2003 clam
Spec. #s: CEGH-UNC 16718, 16716, 16717, 17350
 Nuculida - Praenuculidae
Cuyopsis symmetricus n. gen. n. sp., Villicumia canteraensis n. gen. n. sp., Trigonoconcha acuta n. gen. n. sp., "Emiliania cuerdai n. gen. n. sp." = Emiliodonta cuerdai, Concavodonta ovalis n. sp., Hemiconcavodonta sp. n. gen., Hemiconcavodonta minuta n. gen. n. sp., Praenucula sp.
Cuyopsis symmetricus n. gen. n. sp. Sanchez 1999 clam
Spec. #s: CEGH-UNC 16719 (holotype), 16155b, 16720, 16721, 16756c, 17357, 17358, 17362b, 17364
Villicumia canteraensis n. gen. n. sp. Sanchez 1999 clam
Spec. #s: CEGH-UNC 16152a (holotype), 16153a, 16154, 16155a, 16156, 16157, 16172c, 16772b, 17361b
Trigonoconcha acuta n. gen. n. sp. Sanchez 1999 clam
Spec. #s: CEGH-UNC 16158 (holotype), 16153b, 16153c, 16159, 16160, 16161a, 16162, 16163, 16167b, 16172d, 16715b, 16756b, 16715b
"Emiliania cuerdai n. gen. n. sp." = Emiliodonta cuerdai Sanchez 1999 clam
Spec. #: CEGH-UNC 16164a, 16161b, 16165, 16170a, 16756d, 16767b, 17354, 17355, 17361c
Concavodonta ovalis n. sp. Sanchez 1999 clam
Spec. #'s: CEGH-UNC 16168 (holotype), 16166, 16169, 17351, 17352, 17353, 17356 [entered as Cocavodonta ovalis]
Hemiconcavodonta sp. n. gen. Sanchez 1999 clam
Spec. #: CEGH-UNC 16172b
Hemiconcavodonta minuta n. gen. n. sp. Sanchez 1999 clam
Spec. #s: CEGH-UNC 16171 (holotype), 16152b, 16172a, 16714b, 16777b, 17363
Praenucula sp. Pfab 1934 clam
Spec. #: CEGH-UNC 16170b
 Nuculanida - Malletiidae
Concavoleda braulense n. gen. n. sp.
Concavoleda braulense n. gen. n. sp. Sanchez 1999 clam
Spec. #s: CEGH-UNC 16714a (holotype), 16153d, 17361d, 16780b
Rhynchonellata
 Orthida - Plaesiomyidae
Dinorthis sp. Hall and Clarke 1892
 Orthida - Hesperorthidae
Hesperorthis sp. Schuchert and Cooper 1931
 Orthida - Draboviidae
? Drabovia sp. Havlicek 1950
 Orthida - Dalmanellidae
Strophomenata
 Strophomenida - Leptellinidae
? Anchoramena sp. Benedetto 1995
 Strophomenida - Aegiromenidae