A complete skeleton exposed in ventral view – the holotype specimen of A. megacephalus (BRSMG Cb 2335). The skeleton was housed in the Bristol City Museum and Art Gallery, but it was destroyed by enemy action during the Blitz in World War II. However, surviving plaster casts are housed in the Natural History Museum, London (NHMUK R1309/1310); the Geology Museum, Trinity College Dublin (TCD.47762a, TCD.47762b; Wyse Jackson 2004) and in the British Geological Survey, Keyworth, Nottingham (BGS GSM 118410).
