Macrochiridothea michaelseni Ohlin, 1901

Poore, Gary C. B., 2009, A new species of Chaetiliidae (Crustacea: Isopoda: Valvifera) from the Río de la Plata estuary, Argentina-Uruguay, and reconsideration of Macrochiridothea and Chiriscus, Zootaxa 2119, pp. 51-65 : 61

Macrochiridothea michaelseni Ohlin, 1901

Macrochiridothea michaelseni Ohlin, 1901: 287 –289, pls 11, 12, fig. 8. — Menzies, 1962: 98, fig. 32. — Hurley & Murray, 1968: 247 –248, fig. 9 (head). — Moreira, 1973: figs 4–6. — Carvacho, 1997: 51 (list).

Material. Syntypes: Brackish pools of delta of Río de las Minas; and Magellan Strait, 22 m [12 fm], Punta Arenas, 53°09'S, 70°55'W, Chile, SMNH (15 specimens).

Diagnosis. Total body length of male 11.5 mm; female smaller than male. Dorsal surface of head, pereon and pleotelson smooth. Lateral lobes on head rounded. Coxa 6 just overlapping pleonite 2. Antenna 1 peduncle, article 2 with anterodistal prolongation. Antenna 2 peduncle, article 4, 1.3 times as long as greatest width; article 5, 2.5 times as long as greatest width. Pereopods 2 and 3 dactyli subchelate, half as long as propodus. Pereopod 5 ischium without a prominent hook on upper margin. Pleopod 2, appendix masculina strongly curved, laterally with minute setae.

Distribution. Punta Arenas, Chile (53°09'S, 70°55'W); 0–22 m depth.

Remarks. Macrochiridothea michaelseni is the type species and distinguished from others by the combination of lack of sculpture, small posterolateral lobe on the head, short coxa 6 and strong anterodistal process on the second article of antenna 2. Menzies (1962) recorded the species north of Punta Arenas, close to the type locality.