Alonso de Pina, 2003: 1031–1045, figs. 1–9, 16, tables 1, 2.
Distribution: M +
Magellan Area: Crucero San José I 1984, Argentina, Golfo San José, 42 ° 20 ’S 64 ° 20 ’W, 22 m (bottom: sand; gear: Van Veen grab) (GMA 03).
Depth range: 22 m.
Type-locality: Campaña AUO 2 / 93, Argentina, Buenos Aires, El Rincón, sta. 27, 39 ° 49 ’ 49 ’’S 61 ° 50 ’ 30 ’’W, 17 m (bottom: 82 % fine sand; gear: Van Veen grab) (GMA 03).
Ecology: Collected from sandy substrata.
Extralimital distribution: Campaña AUO 2 / 93, Argentina, Buenos Aires, El Rincón area, approx. 39 °– 40 °S 61 °– 62 °W, 9–20 m (bottom: predominantly sand; gear: Van Veen grab) (GMA 03).
Extralimital depth range: 9– 20 m.
Type material location: MACN, Buenos Aires.
Remarks: Metharpinia iado is the third species belonging to Metharpinia Schellenberg, 1931 recorded from the Magellan area. Alonso de Pina (2001) had described M. protuberantis from this province and had found that the species showed intermediate morphological characters between the genera Metharpinia and Microphoxus Barnard and Barnard, 1960. These genera are complex from the systematic point of view; and examination of more material should be necessary to redefine them.
Metharpinia iado and M. protuberantis can be easily distinguished from each other by the urosomite 3 unprotuberand dorsally and the epimeron 3 with posteroventral corner rounded in the first species whereas the urosomite 3 is produced upwards and the epimeron 3 has its posteroventral corner produced into a large tooth in the second species. Metharpinia iado is closely related to M. longirostris, the first species described by Schellenberg (1931) for the Magellan area, in the general aspect of the body, rostrum, antennae, gnathopods, peraeopods and unprotuberant urosomite 3; they primarily differ from each other in the setal formulas of the antennae, the number of setae of mouthparts, the setation of appendages, and the setal formulas of epimera, uropods and telson.