European and Mediterranean Thalassinidea (Crustacea, Decapoda) Author Ngoc-Ho, Nguyen Muséum national d’Histoire naturelle, Département Milieux et Peuplements aquatiques, 61 rue Buffon, F- 75231 Paris cedex 05 (France) nngoc-ho @ mnhn. fr. ho@mnhn.fr text Zoosystema 2003 25 3 439 555 journal article 10.5281/zenodo.5402949 1638-9387 5402949 Genus Axius Leach, 1815 TYPE SPECIES . — Axius stirhynchus Leach, 1815 by monotypy. DIAGNOSIS. — Rostrum triangular, margin armed, extending to gastric region. Anterolateral margin of carapace unarmed. Gastric region slightly convex; one short median and two short submedian carinae present; cervical groove well defined to whole length. Abdominal pleura ventrally rounded, that of somite 2 broadest, that of somites 3-5 with lateral tufts of setae.Telson longer than wide with dorsal spines; posterior border convex with median spine. Eyestalk subglobose, cornea pigmented; antennal acicle large. Mx2 scaphognathite with long setae on posterior lobe. Mxp3 endopod pediform, with prominent toothed crest on ischium, P1 unequal; P2 chelate; P5 subchelate. Exopod on Mxp1-3; single epipod on Mxp1-3 and P1-4; single podobranch on Mxp2, Mxp3 and P1-3; single rudimentary arthrobranch on Mxp2, paired arthrobranch on Mxp3 and P1-4; single pleurobranch on P1-5 (small on P5, sometimes a rudiment). Male Plp1 uniramous, unsegmented, female Plp1 uniramous, two-segmented; male Plp2 biramous with appendix interna and appendix masculina , female Plp2 biramous with appendix interna . Uropodal exopod with inconspicuous transverse suture near posterior border.