Macrostylis cerrita Vey & Brix 2009

Macrostylis cerrita Vey & Brix, 2009

urn:lsid:zoobank.org:act:3644D8D7-30A9-462E-9DC1-8D19C948EC9C Macrostylis cerrita Vey & Brix, 2009; pp. 356–370, Figs 1–6.

Modified diagnosis. Body cuticular setules absent. Pereonite 3 posterolateral margins not produced posteriorly. Pereonite 3–4 ventral spines absent. Pereonite 4 lateral margins convex in collum region, concave posteriorly; posterolateral margins not produced posteriorly. Pereonite 7 ventral spine prominent. Pleotelson narrowing evenly towards uropod insertions, lateral margins straight, waist present; posterior apex posteriorly convex, length 0.14 pleotelson length. Pereopod III ischium dorsal lobe tapering, recurved with no apical seta. Pereopod V ischium distodorsally without seta. Operculum elongate, distally tapering, apical width subequal or smaller 0.5 operculum width, lateral fringe of setae distinctly separate from apical row of setae.

Remarks. The original illustration of the habitus (Vey & Brix 2009; Fig. 1 B) shows a conspicuous spine laterally on the pleotelson. This spine was not mentioned in the original description text though. The inspection of the holotype revealed that it does not exist.

The pereopod III ischium dorsal lobe (Fig. 4 E) is of remarkable shape and setation. It is tapering, recurved and an apical seta is lacking. A similar ischium is present in M. balayevi Mezhov, 1989 M. quadratura Birstein, 1970 and M. tumulosa Mezhov, 1989 where the dorsal lobe is tapering and without apical seta. The recurved apical lobe found in M. cerrita, however, might represent a more derived condition. In other species of the genus, the ischium has a convergently similar, hook-shaped appearance. Instead of a recurved dorsal lobe, however, a hook-shaped apical spine-like seta (Fig. 22 O) is present on the dorsal lobe apex. This is the case e.g. in Macrostylis carinifera Mezhov, 1988, M. dorsaetosa Riehl et al., 2012, M. papillata Riehl et al. 2012, M. spinifera Sars, 1864.

Vey and Brix (2009) noticed the lateral mandibular setae and interpreted this character as autapomorphy for M. cerrita. However, the mandibular lateral setae have been recognized already before, e.g. in M. sarsi (Brandt 1992; Fig. 14) and M. magnifica Wolff, 1962 (Mezhov 2000), and are present in all species described since and all type material checked (Riehl, unpublished data). Possibly, those setae are apomorphic for the whole family Macrostylidae.

In accordance with the gender agreement stated in Article 31.2 of the ICZN, the species-group name is changed to be feminine.