Euonyx Norman 1867

• Main Authors: Lowry, J. K., Kilgallen, N. M.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2014
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Malacostraca; Amphipoda; Uristidae; Euonyx; North Atlantic
• Online Access: https://doi.org/10.5281/zenodo.6646934; http://treatment.plazi.org/id/03AE8B60AC17FFC96CC1FCFEFA28C485

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 ...