Palaeastacus argoviensis Förster and Rieber, 1982 from the Aalenian of Wittnau (Switzerland) and Palaeastacus edwardsi Étallon, 1861 from the Callovian of Etrochey (France). A–C: holotype PIM R/36 of P. argoviensis whitened with ammonium chloride: lateral view (A), line drawing (B), dorsal view (C); E–F: original figure of Étallon (1861: pl. 1, fig. 11) of the holotype of P. edwardsi: dorsal view (A), internal view (B). Scale bars: 1 cm. Abbreviations: a: branchiocardiac groove; b: antennal groove; b₁: hepatic groove; c: postcervical groove; cr: carpus; d: gastro-orbital groove; e₁e: cervical groove; i: inferior groove; mr: merus; χ: attachment site of adductor testis muscle; ω: attachement site of mandibular muscle. Photographs: C. Klug. Line drawing: J. Devillez.