Pholidogaster is known from two specimens found in the early Carboniferous rocks of the Midland Valley of Scotland. Historically it was one of the first to show science the evolutionary link between fish and amphibians. Although the early Carboniferous was before the time of the coal measures, the swamps and forests were already beginning to spread, providing the ideal environment for large, amphibious animals.
Features:This animal has a very long and slender body, with small and feeble limbs. The shoulder structure is further back than is usual. Belly scales are present, suggesting that in life it did not just swim, but crawled over hard surfaces as well. The structure of the jaw is not clear, since the jaw bones on both specimens are not well preserved. However, there are large fangs in the front of the mouth, presumably used in hunting.