FIG. 18 in Archaeochiapasidae n. fam., a new early Cenomanian brachyuran family from Chiapas, Mexico, new hypothesis on Lecythocaridae Schweitzer & Feldmann, 2009, and phylogenetic implications (Crustacea, Decapoda, Brachyura, Eubrachyura)

FIG. 18. — Hymenosomatidae MacLeay, 1838 (Hymenosomatoidea MacLeay, 1838): A, generalised hymenosomatid based on Halicarcinus cookii (Filhol, 1885) (modified, after Melrose 1975: fig. 1); B, Trigonoplax unguiformis (De Haan, 1839), Japan: thoracic sternum (much widened) of 3rd young stage crab (modified, after Fukuda 1981: fig. 3D): C, Halicarcinus planatus (Fabricius, 1775), MNHN-IU-2014-11916 (= MNHN-B25960): thoracic sternum (modified, after Guinot 1979: fig. 30A). Abbreviations: c.ca.cx1, arthrodial cavity of P1 coxa; cx5, P5 coxa; mxp3, external maxillipeds; b.p., location of press-button for pleonal locking; r, hymenosomian rim, all around carapace margin; 1-8, thoracic sternites 1-8; 3/4-7/8, sternal sutures 3/4-7/8.