Calaxius Sakai and de Saint Laurent, 1989

Poore, Gary C. B. & Collins, David J., 2009, Australian Axiidae (Crustacea: Decapoda: Axiidea), Memoirs of Museum Victoria 66 (2), pp. 221-287 : 248-250

Calaxius Sakai and de Saint Laurent, 1989

Calaxius Sakai and de Saint Laurent, 1989: 84 (diagnosis, list of species).— Sakai, 1994: 192 (diagnosis).— Clark et al., 2007: 64 (diagnosis). Manaxius Kensley, 2003: 367–368 .

Type species. Calaxius acutirostris Sakai and de Saint Laurent, 1989 , by original designation.

Diagnosis. Carapace smooth or tuberculate; cervical groove visible laterally over third distance to anterolateral margin. Rostrum acutely triangular, with 2 or 3 pairs of lateral spines, longer than eyestalks, not depressed below level of carapace, continuous with definite lateral carinae; supraocular spines prominent; lateral carina with at least 1 spine; submedian carina present, with 1 or few spines; median carina a weak ridge, with 1 or few spines; postcervical carina absent. Abdominal somite 1 pleuron acute; pleuron 2 acute or rounded, pleura 3–5 acute, sometimes with anteroventral tooth, or rounded. Eyestalk cylindrical, articulating; cornea pigmented. Antenna, scaphocerite long. Maxilliped 3 exopod not clearly bent at base of flagellum. Pleurobranchs present above pereopods 2–4; podobranchs and arthrobranchs well developed; epipods present on maxilliped 2 to pereopod 4. Pereopods 1 slightly asymmetrical, with propodus flattened; carpus-propodus upper margin with strong curved spines (rarely obsolete), densely covered with long setae. Pereopods 3–5 propodi with transverse rows of robust setae; dactyli tapering, with longitudinal row of robust setae. Pleopods 3–5, appendix interna present. Pleopod 1 of male absent. Pleopod 2 of male with appendix masculina. Uropodal endopod with lateral and distolateral spines; exopod with transverse suture. Telson with lateral fixed spines and posterolateral robust setae; apex rounded.

Remarks. Sakai and de Saint Laurent (1989) listed eight species. Subsequently, six species have been described, including one originally in the synonymised genus Manaxius Kensley, 2003 ( Clark et al., 2007). While Clark et al.’s (2007) diagnosis serves to enable species to be recognised, it should be added that pleopods 3–5 each possess an appendix interna. Most species can be recognised by the long rostrum, pattern of gastric spines and chelipeds with long spines and dense mat of long setae. The chelipeds of Calaxius euophthalmus ( De Man, 1905) would appear to lack strong spines and setae. Here, we redescribe the type species from Australian material and erect a new genus, Pilbaraxius , for a similar axiid with affinities to Calaxius (see below).