FIGURE 40 in Significance of the sexual openings and supplementary structures on the phylogeny of brachyuran crabs (Crustacea, Decapoda, Brachyura), with new nomina for higher-ranked podotreme taxa

FIGURE 40. Evolution of the abdominal-locking mechanism among the Gymnopleura: ancestral condition in extinct †Palaeocorystoidea (F–I) and derived condition in extant Raninoidea of the family Lyreididae (A–E). A, Lyreidus tridentatus De Haan, 1841, ovig. female 38.0 × 23.0 mm, Australia, New South Wales (MNHN-B13316); B, L. brevifrons Sakai, 1937, male 49.4 × 23.4 mm, New Caledonia (MNHN-B24319): ventral surface, abdomen in locking position (A), abdomen removed (B); C, D, Lysirude channeri (Wood-Mason, 1885), Philippines (MNHN-B11562): sexual dimorphism of episternite 5 hook: strong teeth in male (C, 25.5 × 17.4 mm), blunt, eventually lost, and hook setose in large female (D, 33.7 × 20.5 mm); E, Lyreidus stenops Wood- Mason, 1887, male 33 × 18 mm, Philippines (MNHN-B13367): hook with 2 strong teeth; F, G, †Notopocorystes stokesii (Mantell, 1844), Middle Albian, indeterminate sex, 35 × 22 mm (overall), France (MAB k. 2870): F, ventral surface without abdomen; G, detail of double peg on episternite 5; H, I, †Eucorystes iserbyti Van Bakel, Guinot, Artal, Fraaije & Jagt, 2012, Middle Albian, indeterminate sex, height of image 6.0 mm, France, Marne (MAB k. 2871): H, thoracic sternum without abdomen; I, detail of double peg on salient episternite 5, notice the two recurved teeth. c.s., crescent-shaped suture; d.p., double peg; cx2, cx3, P2, P3 coxae; e4, e5, episternites 4, 5; g4, gynglyme for P1 on thoracic sternite 4; g5, gynglyme for P2 on thoracic sternite 5; G1, first gonopod; h, episternite 5 hook; to, tooth; 4, 5, thoracic sternites 4, 5. C–E, scanning electron micrographs. Scale bars: 100 µm (C, E), 1 mm (D). (C–E, courtesy of J.-M. Bouchard; F–I, courtesy of B. van Bakel).