Writhlington revisited: A polychrome perspective (Part 2)
Biddy Jarzembowski, Chris Proctor and Ed Jarzembowski (UK)
In Part 1 of this article (Writhlington revisited (Part 1): A polychrome perspective), we focused on forest arthropods associated with scale trees (Figs. 1 to 4) that were found in the Coal Measures of Writhlington batch, near Radstock, in southwest England. We now move on to other palaeohabitats represented there some 308 million years ago. All too often, reconstructions and restorations of the Carboniferous combine diverse organisms in a single view of the terrestrial realm. (They are frequently likened to the modern Amazon, but apart from being tropical with luxuriant vegetation, the ancient communities differed in composition, species richness and sedimentary environment.) We have departed from this with several different scenes here based on the fossil assemblages and rock lithologies: mixed forest (Fig. 5), river floodplain (Fig. 6) and river channel, the latter with some large (Fig. 7) and small (Fig. 8) animals.
Fig. 5. The mixed forest is depicted on drier swamp margins as near the raised river banks (levees). This diverse community is still dominated by scale trees (Lepidodendron and Sigillaria species) but with an understorey of seed ferns (Alethopteris and Neuropteris spp.) and tree ferns (Pecopteris sp.). The more herbaceous cover is provided by horsetails (Sphenophyllum, Calamites and Annularia spp.). The plant names are given generically because the species are based on details of bark and foliage which are too small to see in the painting.
Fig. 6. A muddy, upper delta floodplain with temporary shallow lakes and ponds and forest in the background. The reptile (a pelycosaur) in the foreground is only known from footprints resembling the ichnogenus, Pseudobradypus Matthews.
Fig. 7. A river channel with sandy, rippled bottom and submerged, waterlogged scale-tree trunk and sharks swimming around in spawning mode. The latter are based on finds of egg cases resembling Palaeoxyris carbonaria Schimper which are attributed to extinct hybodont sharks (tristychiids).
Fig. 8. A small eurypterid or water scorpion, Adelophthalmus imhofi (Reuss) in the shallows amidst waterlogged Cyperites leaves, Neuropteris pinnule and other plant matter washed in from the river bank. With its poor eyesight, it has yet to find any prey.
