Morphology of the carapace and of the chela of the first pair of pereiopods of Stenodactylina Beurlen, 1928 and species from the Early Jurassic. A: typical carapace groove pattern of Stenodactylina; B: form I of chela of the first pair of pereiopods of Stenodactylina; C: form II of chela of the first pair of pereiopods of Stenodactylina; D–F: holotype FSL 170514 of Stenodactylina falsani (Dumortier, 1867) from the Sinemurian of Saint-Didier-au-Mont-d’Or (France): ventral view (D), external view (E), internal view (F); G–H: Holotype SMNS 7785 of Stenodactylina liasina Beurlen, 1928 from the Toarcian of Holzmaden (Germany): general view (G), line drawing (H); I–J: original figures of Étallon (1861: pl. 1, fig. 10) of the holotype of Stenodactylina spinosa (Étallon, 1861) n. comb. from the Toarcian of Les Nans (France): ventral view (I), outer view (J); K: original figure of Förster (1966: pl. 17, fig. 5) of a specimen of S. spinosa from the Toarcian of Perrigny (France). Scale bars: 1 cm. Abbreviations: a: branchiocardiac groove; b: antennal groove; b₁: hepatic groove; c: postcervical groove; d: gastro-orbital groove; e₁e: cervical groove; i: inferior groove; ip: intercalated plate; PoA: post-orbital area; χ: attachment site of adductor testis muscle; ω: attachement site of mandibular muscle. Photographs: L. Cazes (D–F), J. Devillez (G). Line drawings: J. Devillez.