Macrobrachium acanthurus (Wiegmann, 1836)

Santana, Laira Lianos Michelle Mollemberg Laurindo André Rodrigues Michelle Pinheiro Vetorelli William, 2018, Checklist of the species of Macrobrachium Spence Bate, 1868 (Decapoda: Caridea: Palaemonidae) from the lower Parnaíba River basin, Piauí, Brazil, Nauplius (e 2018017) 26, pp. 1-8 : 3

Macrobrachium acanthurus (Wiegmann, 1836)

( Fig. 2A–D )

Material examined. Brazil, Piauí: Portinho Lagoon , ix.2013, 10 males, 8 females [ CZDP ( F2 ) 0056]. Idem, 20.ii.2014, 6 males, 8females [ CZDP ( F2 ) 0058]. Idem, 15.v.2013, 1 male, 2 females ( LSZ 0019 ). Prata Lagoon, 20.xii.2014, 3 males, 4 females [ CZDP ( F2 ) 0055] .

Distribution. In Brazil, this species has been recorded in the states of Amapá, Pará, Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, Bahia, Espírito Santo, Rio de Janeiro, São Paulo, Paraná, Santa Catarina and Rio Grande do Sul ( Melo, 2003; Pimentel and Magalhães, 2014; present work).

Remarks. This is the first record of this species from the lower Parnaíba River basin and the northern portion of the state of Piauí, with only one documented previous record in the state from the municipality of Jaicós ( Ferreira et al., 2010). This species can be differentiated from its congeners through a combination of characters of the rostrum and telson ( Valencia and Campos, 2007): rostrum slightly sinuous and apex somewhat curved upward, usually overreaching scaphocerite; upper margin of rostrum with 8–12 teeth, with proximal teeth closer to each other, including 1–3 teeth completely postorbital; lower margin of rostrum with 4–7 teeth; telson terminal margin ending in sharp midpoint, with 2 pairs of spinules laterally, inner pair overreaching midpoint.

Figures

Figure 2. Macrobrachium acanthurus (Wiegmann, 1836), female (LSZ 019). A, Detail of the anterior region of the carapace; B, habitus, lateral view; C, detail of the telson and uropods, dorsal view; D, habitus, dorsal view. Scale bar: 1 cm.