Minuca burgersi (Holthuis, 1967)

Masunari, Setuko, Martins, Salise Brandt & Anacleto, Andre Fernando Miyadi, 2020, An illustrated key to the fiddler crabs (Crustacea, Decapoda, Ocypodidae) from the Atlantic coast of Brazil, ZooKeys 943, pp. 1-20 : 1

Minuca burgersi (Holthuis, 1967) Figures 1B , 4B , 7B , 8C, D

Recognition characters.

Carapace pentagonal moderately arched in the anteroposterior direction and dorsal surface without pile (Fig. 8C ). Dorso-lateral margins well-marked and converging posteriorly; major and minor pairs of postero-lateral striae clearly visible (Fig. 8C ). Front triangular and very wide making up from 36% to 41% of the front-orbital breadth (Fig. 1B ). Male major claw manus covered by small tubercles and provided with a strong groove (sometimes filled with dirt) on dorsal surface following the dorsal margin; fingers thick and slightly flattened; dactyl little longer than manus; pollex and dactyl curved forming a large gap (Fig. 8D ). First three ambulatory legs with pile (= woolly pubescence) limited to dorsal surface of carpus and manus (Fig. 4B , setae), absent in ventral margin; all ambulatory legs with narrow merus and dorsal margin almost strait; last pair of ambulatory legs without piles and merus less than two 1.5 times wider than respective carpus in its maximum breadth (Fig. 7B ). Male abdominal segments never fused. Medium-sized species and one of the smallest in the genus; males’ carapace width (CW) up to 19.0 mm in a population from Fortaleza, CE, Brazil ( Crane 1975).

Biological notes.

The species reproduces year-round in the population of Ubatuba, southeastern Brazil ( Benetti et al. 2007). It occurs in oligohaline and mesohaline areas and on sandy substrate although in low densities ( Masunari 2006; Thurman et al. 2013).

Remarks.

The species is morphologically close to its congeners M. rapax and M. mordax ; the distinguishing characters among these species are treated in the subsequent items.

Figures

Figure 1. Carapace, frontal view. A Uca maracoani: spatulate and narrow front (seta) B Minuca burgersi: triangulate and wide front (seta).

Figure 4. Third ambulatory leg, posterior view. A Minuca mordax with pile on dorsal surface of merus (seta) and carpus and all around surfaces of manus (seta) B Minuca burgersi with pile limited to dorsal surface of carpus and manus (seta).

Figure 7. Last ambulatory legs, posterior view. A Minuca rapax, wide merus (seta). B Minuca burgersi, narrow merus (seta).

Figure 8. Minuca rapax. A carapace with two pairs of postero-lateral striae, dorsal view B male major claw, frontal view. Minuca burgersi C Carapace with two pairs of postero-lateral striae, dorsal view D male major claw, frontal view.