Vargas Pena Shale (Silurian of Paraguay)

Where: Paraguay (25.4° S, 57.3° W: paleocoordinates 44.8° S, 142.4° W)

• coordinate based on political unit

• local area-level geographic resolution

When: Vargas Pena Shale Formation, Llandovery (443.4 - 433.4 Ma)

• Harrington provisionally places this formation as Llandovery. Grahn and Gutierrez (2001, PBDB ref. 7139), on the basis of chitinizoan zonation, conclude that it spans Rhuddanian to Telychian ages.

• formation-level stratigraphic resolution

Environment/lithology: marine; micaceous claystone and argillaceous sandstone

• "The Vargas Pena Shale forms a minor intercalation within the upper part of the Itacurubi Group, conformably interposed between the underlying Ayala Sandstone and the overlying Cariy Sandstone. The beds are clearly of marine origin and were probably deposited under shallow, proximal, neritic environment."
• "[In type locality:] shales altered to white micaceous clay, in places stained yellow, brown, and red...The very poor and scarce outcrops along Rio Piribebuy...consist of very light grayish-white micaceous clay-shale, with thin intercalations of soft, very shaly, fine-grained sandstones."

Collection methods: I have combined lists from type locality (responsible for the great majority of taxa) and from the "poor and scarce outcrops." See PBDB collection 908 for additional taxa.

Primary reference: H. J. Harrington. 1972. Silurian of Paraguay. Geological Society of America Special Paper 133:41-50 [M. Foote/M. Foote/M. Foote]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 25570: authorized by Michael Foote, entered by Michael Foote on 18.09.2002, edited by Pete Wagner and Austin Hendy

Creative Commons license: CC BY (attribution)

Taxonomic list

Foraminifera
 Ammodiscoidea - Saccamminidae
 Textulariina - Hyperamminidae
Hyperammina sp. Brady 1879
Trilobita
 Phacopida - Phacopidae
Eophacops sp. Delo 1935 trilobite
"Eophacops" nov. sp. Wolfart
 Phacopida - Dalmanitidae
? Dalmanites sp. Barrande 1852 trilobite
 Phacopida - Calymenidae
Lingulata
 Lingulida - Lingulidae
Lingula sp. BruguiƩre 1797
Strophomenata
 Strophomenida - Leptostrophiidae
"Australostrophia ? conradii" = Eostropheodonta conradii
"Australostrophia ? conradii" = Eostropheodonta conradii Harrington 1950
Rhynchonellata
 Rhynchonellida - Leptocoeliidae
Lophophorata
 Tentaculitida - Tentaculitidae
Tentaculites sp. von Schlotheim 1820
Hyolitha
 Hyolithida - Hyolithidae
Hyolithes guaraniensis
[entered as Hyolilthes guaraniensis]
Bivalvia
  -
Bivalvia indet.1 Linnaeus 1758 clam
 Nuculanida - Malletiidae
? Palaeoneilo sp. Hall and Whitfield 1869 clam
 Nuculanida - Cucullellidae
 Solemyida - Ctenodontidae
 Nuculida - Nuculidae
? Nucula sp. Lamarck 1799 nut clam
 Modiomorphida - Allodesmatidae
Gastropoda
 Murchisoniina -
Murchisonioidea indet.2 Koken 1896 snail
 Murchisoniina - Eotomariidae
Eotomaria sp. Ulrich and Scofield 1897 snail
 Murchisoniina - Phanerotrematidae
? Ulrichospira sp. Donald 1905 snail
Cephalopoda
 Orthocerida - Orthoceratidae
Crinoidea
  -
Crinoidea indet. Miller 1821 Sea lily
Pterobranchia
 Graptoloidea - Monograptidae
"Climacograptus innotatus" = Paraclimacograptus innotatus
"Climacograptus innotatus" = Paraclimacograptus innotatus Nicholson 1869 graptolite
subsp. brasiliensis Ruedemann
 Graptoloidea - Diplograptidae
 Graptoloidea - Climacograptidae
Climacograptus sp. Hall 1865 climacograptid