Miospores et acritarches de la formation d'Hydrequent (Frasnien superieur à Famennien Inferieur, Boulonnais, France)

The upper part of the Hydrequent Shales, which are inserted between the last dolomite layer and the Ste Godeleine Sandstone, consists of at least 20 m of shaly sediments with thin sandy partings. The 44 samples studied have yielded numerous spore and acritarch species which permit a very detailed palynological zonation to be established, mainly corresponding to the upper Frasnian. The highest samples, 0.5 m below the Ste Godeleine Sandstone, can be correlated with the lower Famennian of the Belgian stratotype. The Frasnian-Famennian boundary thus falls within the Hydrequent Shales between 0.5 and 2.5 m below the Ste Godeleine Sandstone

New morphological information on, and species of placoderm fish Africanaspis (Arthrodira, Placodermi) from the Late Devonian of South Africa

Here we present a new species of placoderm fish, Africanaspis edmountaini sp. nov., and redescribe Africanaspis doryssa on the basis of new material collected from the type locality of Africanaspis. The new material includes the first head shields of Africanaspis doryssa in addition to soft anatomy for both taxa. Hitherto Africanaspis was entirely described from trunk armour and no record of body and fin outlines had been recorded. In addition the first record of embryonic and juvenile specimens of Africanaspis doryssa is presented and provides a growth series from presumed hatchlings to presumed adults. The presence of a greater number of juveniles compared to adults indicates that the Waterloo Farm fossil site in South Africa represents the first nursery site of arthrodire placoderms known from a cold water environment. The preservation of an ontogenetic series demonstrates that variation within the earlier known sample, initially considered to have resulted from ontogenetic change, instead indicates the presence of a second, less common species Africanaspis edmountaini sp. nov. There is some faunal overlap between the Waterloo Farm fossil site and faunas described from Strud in Belgium and Red Hill, Pennsylvania, in north America, supporting the concept of a more cosmopolitan vertebrate fauna in the Famennian than earlier in the Devonian

Observations on the establishment of a Devonian and Lower Carboniferous high resolution miospore biostratigraphy

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