Figure 6 in The morphological and functional variability of pleon-holding mechanisms in selected Eubrachyura (Crustacea: Decapoda)

Figure 6. Examples of female Gecarcinucidae with pleon-holding structures still present. a-b: Ceylonthelphusa rugosa (Kingsley, 1880), ♀, 54 × 42 mm, Sri Lanka (ZRC1998.650). (a) Thoracic sternum without pleon. Very small vestigial buttons present. (b) Ventral surface of pleon. No socket visible on completely flat sixth pleon segment. c-d: Parathelphusa valida Ng & Goh, 1987, ♀, 48 × 38 mm, Malaysia (ZRC1996.1999). (c) Thoracic sternum without pleon. Large round buttons visible on S5. Sterno-abdominal cavity without pronounced edge, but still triangular. (d) Ventral surface of pleon. Socket shallow, but present in middle of sixth pleon segment. A: anterior; B: button; fl: flat surface of P6; P: posterior; pl: pleopod; s: setae; sac: sterno-abdominal cavity; so: socket; S5: sternite 5; t: telson; v: vulva; vb: vestigal buttons. Scale bar = 5 mm.