Macrochiridothea lilianae Moreira, 1972

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 : 59-60

Macrochiridothea lilianae Moreira, 1972

Macrochiridothea lilianae Moreira, 1972: 395 –399, fig. 1A. — Moreira, 1973: 22 –25, 32–39, figs 48–76. — Carvacho, 1997: 51 (list).

Material. Lectotype: Pota do Catimbau, Ilha Anchieta, São Paulo, Brazil, 21 m, 23°35´S, 45°05´W, MZUSP (male, 5.0 mm, designated as “ holotype ” by Moreira, 1973). Southern Brazil, 23°12´S – 29°13´S, 12–33 m depth.

Paralectotypes: collected with holotype, MZUSP (59 specimens).

Diagnosis. Total body length of male 5 mm; female 6 mm. Dorsal surface of head, pereon and pleotelson smooth. Lateral lobes on head rounded. Coxa 6 just overlapping pleonite 2. Antenna 1 peduncle article 2 without anterodistal prolongation. Antenna 2 peduncle, article 4, 1.7 times as long as greatest width; article 5, 3 times as long as greatest width. Pereopods 2 and 3 dactyli minute, hook-like. Pereopod 5 ischium without a prominent hook on upper margin. Pleopod 2, appendix masculina straight, apex laterally denticulate.

Distribution. Southern Brazil, 23°12´S – 29°13´S, 12–33 m depth.

Remarks. Moreira clearly expected his extended species description (submitted 17 August 1971, published 1973) to have priority over his 1972 paper on distribution of Macrochiridothea . This was not to be and his 1972 figures and short diagnoses are sufficient to qualify as published names for this and the following species. The 60 specimens he mentioned in 1972 are syntypes and the “ holotype ” designated in 1973 is in fact a lectotype (ICZN Article 74.6).

The female is larger and more vaulted than the male. Macrochiridothea lilianae is the only species for which a sexually dimorphic pereopod 2 (and possibly 3) is described. Pereopods 2 and 3 of the female have a prolonged setose posterodistal lobe on the carpus and simple setae on distal margins of the propodus. In the male the carpal posterodistal corner is not produced but the posterior margins of the carpus and propodus carry a dense field of fine setae. Jaramillo (1982) reported a similar species from Chile (see M. aff. lilianae below).