A generic review of the lysianassoid family Uristidae and descriptions of new taxa from Australian waters (Crustacea, Amphipoda, Uristidae) Author Lowry, J. K. Author Kilgallen, N. M. text Zootaxa 2014 2014-09-26 3867 1 1 92 journal article 3965 10.11646/zootaxa.3867.1.1 e5bb465f-e713-45c1-8e0f-2c6125494b44 1175-5326 5585734 B7C6EC5F-5AA3-43B1-BD3D-D8111E0EC3A7 Euonyx Norman, 1867 ( Fig. 9 ) Euonyx Norman, 1867: 202 .— Sars, 1891: 116 .— Stebbing, 1906: 19 (in part). Pirlot, 1936: 116 (in part).—J.L. Barnard, 1969: 342 (in part).— Lincoln, 1979: 54 (in part).— Lowry & Stoddart, 1989: 519 .— Barnard & Karaman, 1991: 485 , fig. 92I (in part). Leptochela Boeck, 1876: 190 (homonym, Decapoda ) ( type species, Opis leptochela Bate & Westwood, 1868 , monotypy. Type species . Euonyx chelatus Norman, 1867 , monotypy. Included species. Euonyx includes four species: E. chelatus Norman, 1867 ; E. coecus Pirlot, 1933 E . urania sp. nov. ; E . xarifa sp. nov. Incertae sedis . Euonyx conicurus K.H. Barnard, 1955 (genus uncertain); Diagnostic description. Antenna 1 peduncle article 1 without anterodistal lobe; accessory flagellum with an elongate article 1 (at least twice as long as article 2) partially covering callynophore. Antenna 2 without brush setae. Mandible molar a large, asetose flap or absent. Maxilla 1 outer plate with reduced seta-teeth in a modified 7/4 crown . Maxilla 2 inner plate subequal to or significantly shorter than outer plate. Gnathopod 1 chelate ; coxa 1 reduced, significantly shorter than coxa 2, tapering distally or subquadrate ; ischium long (length 2 × to 4 × breadth) too very long (length 4 × to 6 × breadth) ; carpus long (length 2 to 4 × breadth); propodus margins subparallel. Uropod 2 inner ramus not constricted. Telson deeply cleft . Remarks. Euonyx appears to be the immediate sister taxon of Stephonyx Lowry & Stoddart, 1989 . Euonyx has abandoned the scavenging life-style to become an ectoparasite of echinoids and in the process developed severely reduced mouthparts, particularly the seta-teeth of the maxilla 1 outer plate. In Euonyx coecus Pirlot, 1933 the setal-teeth of maxilla 1 appear to be intermediate between Euonyx and Stephonyx , but the mandibular molar is absent, an important characteristic of Euonyx . Distribution. North Atlantic Ocean. Indonesia . Eastern Australia . Key to Euonyx species 1. Antenna 1 peduncular article 1 without anterodistal lobe................................................ E. xarifa - Antenna 1 pedunculararticle 1 withsmalltolargeanterodistallobe ............................................ 2 2. Gnathopod 1 carpus longer than propodus........................................................... E. urania - Gnathopod 1 carpusshorterthanorsubequaltopropodus .................................................... 3 3. Urosomite 1 dorsal margin a broad angled wedge................................................... E. chelatus - Urosomite 1 dorsalmarginanacutetriangularprocess .........................................? Euonyxconicurus - Urosomite 1 dorsalmarginaroundedboss ..................................................... Euonyxcoecus