Silurian and Devonian clathrodictyids and other stromatoporoids from the Broken River region, north Queensland

Abstract

Stromatoporoids are well represented in the carbonate depositional phases of the Middle-Upper Silurian Jack Formation, the Lower-Middle Devonian Shield Creek Formation and Broken River Group of north Queensland. A total of 4 species of Labechiida, 4 species of Actinostromida, 14 species (4 new) of Clathrodictyida and 5 species (1 new) of Stromatoporellida are described and illustrated. They include the new species Gerronostroma doseyense, G.? apertum, Schistodictyon jackense, Atelodictyon repandum and Hermatostroma malletti. The fauna comprises representatives of Cystostroma, Labechiella, Stylostroma, Actinostroma, Aculatostroma, Ecclimadictyon, Plexodictyon, Anostylostroma?, Nexililamina, Pseudoactinodictyon, Tienodictyon, Simplexodictyon, Stromatopororella, Stictostroma, Trupetostroma?, Amnestostroma and Stachyodes. Included are revisions of a number of C.W. Mallett's species first described in the early 1970s. The genus Nexililamina Mallett is reinterpreted as a clathrodictyid. The history of the ‘less advanced’ labechiids suggests they came close to extinction in the Early Devonian. However, they survived as a distinctive, relict stock in the Lower Devonian Broken River assemblages (up to 4 genera recorded), and lived in close association with non-labechiid components of the fauna.