Upper Allt Ddu trilobites (Ordovician of the United Kingdom)

Where: Wales, United Kingdom (52.9° N, 3.6° W: paleocoordinates 52.2° S, 18.4° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Diplograptus multidens graptolite zone, Allt Ddu Formation (Lower Bala Group), Soudleyan (458.4 - 457.2 Ma)

• upper assemblage zone

• member-level stratigraphic resolution

Environment/lithology: marine; lithified, bioturbated, phosphatic, blue, silty mudstone and lithified siltstone

• Allt Ddu mudstones: monotonous series of dark blue silty mudstones with fine siltstones commonly disposed in small-scale cross- and ripple-lamination...greatly disturbed by burrowing organisms and bedding is poorly developed except in coarser beds...small phosphatic nodules occur sparely throughout the upper part, becoming more abundant near the top. [Bassett et al 1966, Quart J Geol Soc 122: 219-271]

Size class: macrofossils

Preservation: mold/impression

Reposited in the BMNH

Primary reference: H. B. Whittington. 1968. The Ordovician trilobites of the Bala Area, Merioneth. Part IV. Monograph of the Palaeontographical Society 122(520):93-138 [M. Hopkins/M. Hopkins]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 188589: authorized by Melanie Hopkins, entered by Melanie Hopkins on 08.09.2017

Creative Commons license: CC BY (attribution)

Taxonomic list

 Strophomenida - Sowerbyellidae
"Sowerbyella musculosa" = Sowerbyella (Sowerbyella) musculosa
"Sowerbyella musculosa" = Sowerbyella (Sowerbyella) musculosa Williams 1963
 Strophomenida - Strophomenidae
Strophomena sp. Rafinesque and De Blainville 1824
 Strophomenida - Rafinesquinidae
"Kiaeromena cf. kjerulfi" = Kiaeromena (Kiaeromena) kjerulfi, Leptaena ventricosa, "Macrocoelia prolata" = Colaptomena expansa prolata
"Kiaeromena cf. kjerulfi" = Kiaeromena (Kiaeromena) kjerulfi Holtedahl 1916
Leptaena ventricosa Williams 1963
"Macrocoelia prolata" = Colaptomena expansa prolata Williams 1963
 Orthotetida - Triplesiidae
 Rhynchonellida - Trigonirhynchiidae
 Orthida - Dalmanellidae
"Howellites ultima" = Howellites ultimus
"Howellites ultima" = Howellites ultimus Bancroft 1945
 Orthida - Harknessellidae
 Orthida - Hesperorthidae
Dolerorthis sp. Schuchert and Cooper 1931
 Orthida - Plaesiomyidae
Dinorthis berwynensis Whittington 1938
 Phacopida - Homalonotidae
Brongniartella minor Salter 1852 trilobite
 Trinucleida - Trinucleidae
Broeggerolithus broeggeri Bancroft 1929 trilobite