Smaraldia Lowry & Stoddart 2012, gen. nov.

Smaraldia gen. nov.

Type species. Smaraldia springthorpei sp. nov.

Etymology. “Smarald” is an obsolete English word for “emerald”, the colour of the type species.

Diagnostic description. Body shape slender. Head lateral cephalic lobe large, broadly rounded. Antenna 1 peduncular article 1 without posterodistal spine; accessory flagellum article 1 long; flagellum with callynophore in female. Mandible with accessory setal row absent; left lamina dentata absent; palp attached distally; palp article 2 broad, article 3 tapered distally. Maxilla 1 outer plate setal-teeth smooth, at least one inner row setal-tooth absent; palp absent. Maxilliped inner plate absent; outer plate medium size; palp 4-articulate, article 4 large. Gnathopod 1 ischium smaller than propodus; corner of palm without robust seta. Gnathopod 2 palm obtuse. Epimeron 3 posteroventral corner broadly rounded. Uropod 3 biramous.

Species composition. Smaraldia springthorpei sp. nov.

Remarks. Smaraldia appears to be most similar to the Antarctic genus Ultimachelium. Both genera have a long slender first article on the accessory flagellum, maxilla 1 palp absent and a well-developed fourth article on the maxillipedal palp. They differ in the ischium of gnathopod 1 (which is significantly smaller than the propodus and not swollen posteroproximally in Smaraldia but subequal to or larger than, in one species slightly smaller than, the propodus and swollen in Ultimachelium) and in the posteroventral corner of epimeron 3 (which is broadly rounded in Smaraldia and projecting and narrowly rounded in Ultimachelium). Smaraldia is currently monotypic and confined to southern Australia. Ultimachelium is found in southern South America and Antarctica.