Jassagruneri Conlan, 1990

Conlan, Kathleen E., Desiderato, Andrea & Beermann, Jan, 2021, Jassa (Crustacea: Amphipoda): a new morphological and molecular assessment of the genus, Zootaxa 4939 (1), pp. 1-191 : 156-158

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.

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) .

Figures

FIGURE 12. Records of Southern Hemisphere species of Jassa (continued). Red dot: identification confirmed by specimen examination; green dot: literature record (Supplementary Table S1) with identification not confirmed but judged likely to be this species; blue x: suspected or known to be on the hull or interior of a boat or ship.

FIGURE 102. Jassa gruneri 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. Jassa gruneri 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.