Jassa (Crustacea: Amphipoda): a new morphological and molecular assessment of the genus Author Conlan, Kathleen E. 0000-0002-2263-7075 kconlan@nature.ca Author Desiderato, Andrea 0000-0002-2263-7075 kconlan@nature.ca Author Beermann, Jan 0000-0002-2263-7075 kconlan@nature.ca text Zootaxa 2021 2021-03-04 4939 1 1 191 journal article 7102 10.11646/zootaxa.4939.1.1 ee8e66ff-2f2c-47e2-978b-be52996d5b0f 1175-5326 4580622 F33F42D0-A139-4CE3-97D7-1314C12CF86B Jassagruneri Conlan, 1990 ( Table 13 , Figs 102–103 ) Diagnosis. Both sexes: Mandibular palp : article 2, dorsal margin without a fringe of setae. Maxilla 1 : without a cluster of setae at the base of the palp article 1. Gnathopod 1 : basis, anterolateral margin with only a few short setae distally; carpus without a single or small cluster of short setae at the anterodistal junction of the propodus. Gnathopod 2 : basis with a few or a full row of setae along the anterolateral margin (setal lengths 50% of the basis width); carpus and propodus, setae on the anterior margin short and simple (setal length <basis width). Pereopods 5–7 : propodus not expanded anteriorly. Uropod 1 : ventral peduncular spinous process underlying about 40% of the longest ramus. Uropod 3 : inner ramus without spines mid-dorsally (with only the single apical spine). Telson : tip without apical setae (only the usual short setae at each dorsolateral cusp). Thumbed male: unknown. Adult female: Antenna 2 : without plumose setae on the flagellum and peduncular article 5. Gnathopod 2 : propodus, palmsinuous. FIGURE 102. Jassagruneri Conlan, 1990 . Holotype, juvenile male, 2.1 mm, NMCC 1987-1077; allotype, adult female, 3.2 mm, NMCC 1987-1078. Hobart Harbour, Tasmania (42°50ʹS, 147°20ʹE), 8 November 1978, G. Edgar, coll., SCUBA, algal washes, 3–5 m depth, 1978-287 (CMN). Lateral views. Scale 0.1 mm. Illustration after Conlan (1990) . FIGURE 103. Jassagruneri Conlan, 1990 . Holotype, juvenile male, 2.1 mm, NMCC 1987-1077. Hobart Harbour, Tasmania (42°50ʹS, 147°20ʹE), 8 November 1978, G. Edgar, coll., SCUBA, algal washes, 3–5 m depth, 1978-287 (CMN). Mouthparts. Lateral view: maxilla 1; other views medial. Scale 0.1 mm. Remarks. This is a small-bodied species with the juvenile male holotype 2.1 mm and the adult female allotype 3.2 mm ( Conlan 1990 ). It is part of the Southern Hemisphere sinuous-palmed group, keying closest to J. thurstoni . Jassa gruneri differs in the lack of a seta on the carpus of gnathopod 1 at the anterodistal junction of the propodus (present in J. thurstoni ) and in the presence of a row of setae on the basis of gnathopod 2 (absent in J. thurstoni ). This row is more pronounced in the female allotype than the juvenile male holotype ( Fig. 102 ). Currently it is only known from Tasmania and New Zealand . The New Zealand specimen ( Fig. 12 ) is a juvenile male and was found in a collection in Lyttelton harbour described by Chilton (1884) . In this same collection is a specimen used by Chilton to describe his new species Podocerus latipes Chilton, 1884 , which was synonymized by Stebbing (1906) under Jassa frequens ( Chilton, 1883 ) and later transfered to Ventojassa ( Conlan 2021 ) .