Fig. 4 in The earliest record of a diogenid hermit crab from the Late Jurassic of the southern Polish Uplands, with notes on paguroid carapace terminology

Fig. 4. Explanation of the hypothesised origin (centre) of the cervical groove and massetic region, in transition from the Triassic anomuran Platykotta akaina (A) to Eopaguropsis nidiaquilae sp. nov. (B).