Acaste subcaudata-Trimerus n. sp. Assemblage of the Gray Sst. Grp., SW Dyfed (Silurian of the United Kingdom)

Also known as Fauna IV of Walmsley and Bassett (1976), PBDB ref. 6649

Where: England, United Kingdom (51.9° N, 4.2° W: paleocoordinates 30.7° S, 14.9° W)

• coordinate based on political unit

• local area-level geographic resolution

When: Sheinwoodian (433.4 - 430.5 Ma)

Environment/lithology: marine; lag sandstone

• "Gray Sst. underlain by Coralliferous Grp with its BA 4 Costistricklandia fauna and ovelain by ssts of the Old Red facies. Environment probably high energy shallow marine. Generically identical assemblages occur in the Wenlock ssts of the Uks and Totworth Inliers, UK. A BA 2-3 assignment is reasonable. Assemblage grades laterally into one of similar type which contains [list] indicating more normal marine conditions (BA 3)
• "..occurs in thin (0.15 m) decalcified sandstone beds as lag accumulations. Some sandstones in the sequence show megaripples, lenticular bedding and other evidence of shallow-water conditions."

Size class: macrofossils

Primary reference: A. T. Thomas and P. D. Lane. 1999. Trilobite assemblages of the North Atlantic Region. in A. J. Boucot and J. D. Lawson, eds. Paleocommunities--a case study from the Silurian and Lower Devonian. Cambridge University Press, Cambrdige 444-457. [M. Foote/M. Foote/M. Foote]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 23094: authorized by Michael Foote, entered by Michael Foote on 09.07.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Strophomenata
 Orthotetida - Chilidiopsidae
"Coolinia sp." = Fardenia (Coolinia)
"Coolinia sp." = Fardenia (Coolinia) Bancroft 1949
 Strophomenida - Amphistrophiidae
"Pembrostrophia sp." = Amphistrophia (Pembrostrophia), Mclearnites sp.
"Pembrostrophia sp." = Amphistrophia (Pembrostrophia)
 Strophomenida - Rafinesquinidae
Leptaena sp.
Leptaena sp. Dalman 1828
Rhynchonellata
 Spiriferida - Delthyrididae
Howellella sp.
Howellella sp. Kozlowski 1946
 Spiriferida - Cyrtiidae
Eospirifer sp.
Eospirifer sp. Schuchert 1913
 Athyridida - Meristellidae
Meristina sp.
Meristina sp. Hall 1867
 Atrypida - Atrypidae
Atrypa sp.
Atrypa sp. Dalman 1828
 Rhynchonellida - Camarotoechiidae
Camarotoechia sp.
Camarotoechia sp. Hall and Clarke 1893
 Orthida - Draboviidae
Salopina sp.
Salopina sp. Boucot 1960
 Lophophorata -
Tentaculitida indet.
Tentaculitida indet. Ljaschenko 1955
Cephalopoda
 Orthocerida - Dawsonoceratidae
Dawsonoceras sp.
Dawsonoceras sp. Hyatt 1884
Gastropoda
  -
Gastropoda indet.
Gastropoda indet. Cuvier 1795 snail
Bivalvia
  -
"Pelecypoda indet." = Bivalvia
"Pelecypoda indet." = Bivalvia Linnaeus 1758 clam
Trilobita
 Phacopida - Homalonotidae
Trimerus sp.
Trimerus sp. Green 1832 trilobite
Trimerus n. sp.
 Phacopida - Acastidae
Acaste subcaudata