taxonID	type	description	language	source
D05BFC048A60FFCCFF4EF951A443F87A.taxon	description	(Fig. 2 A – D) Material examined. Brazil, Piauí: Portinho Lagoon, ix. 2013, 10 males, 8 females [CZDP (F 2) 0056]. Idem, 20. ii. 2014, 6 males, 8 females [CZDP (F 2) 0058]. Idem, 15. v. 2013, 1 male, 2 females (LSZ 0019). Prata Lagoon, 20. xii. 2014, 3 males, 4 females [CZDP (F 2) 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.	en	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: 1-8, DOI: 10.1590/2358-2936e2018017, URL: https://doi.org/10.1590/2358-2936e2018017
D05BFC048A61FFCDFF52FBEAA45AF96D.taxon	description	(Fig. 3 A – D) Material examined. Brazil, Piauí: Portinho Lagoon, 20. ii. 2014, 60 specimens [CZDP (F 2) 0054]. Idem, 19. vii. 2014, 65 specimens [CZDP (F 2) 0060]. Idem, 19. vii. 2014, 3 males (LSZ 030). Parnaíba River, 04. iii. 2013, 40 specimens [CZDP (F 2) 0057]. Prata Lagoon, 20. xii. 2014, 100 specimens [CZDP (F 2) 0059]. Distribution. In Brazil, this species has been recorded in the states of Acre, Roraima, Rondônia, Amapá, Amazonas, Pará, Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Bahia, Tocantins, Goiás, Mato Grosso, Mato Grosso do Sul, Minas Gerais, São Paulo and Paraná (Melo, 2003; Pileggi et al., 2013; Pimentel and Magalhães, 2014; present work). Remarks. Ramos-Porto and Coelho (1998) as well as Melo (2003) cited the occurrence of M. amazonicum from Piauí, however, they did not mention the material examined and locality. This is the first record of M. amazonicum from the lower Parnaíba River basin. According to Magalhães et al. (2005), adults of M. amazonicum are easily recognized by the long and sinuous rostrum, which is arched over the orbits and obliquely curved upward distally. Telson somewhat conical, tapering gradually toward to the tip, ending in an acute median point with no distinct discontinuity, with two pairs of spines in the posterior half of the lateral margins, inner pair not overreaching the apex of the telson. In immature and juvenile specimens these characters can be misleading, especially in comparisons with M. jelskii. However, the telson of M. jelskii have a distinct posterior margin, with a clear discontinuity between the lateral margins and the median point, and the inner pair of spines of the posterolateral margins is always longer than the median point of the telson (Magalhães et al., 2005).	en	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: 1-8, DOI: 10.1590/2358-2936e2018017, URL: https://doi.org/10.1590/2358-2936e2018017
D05BFC048A61FFCBFCF3F900A57FFDFA.taxon	description	(Fig. 4 A – D) Material examined. Brazil, Piauí: Parnaíba River, 23. iii. 2018, 1 male [CZDP (F 2) 0061], 1 male [CZDP (F 2) 0062]. Distribution. This species is found in Brazil in the states of Amapá, Pará, Piauí, Pernambuco, Alagoas, Espírito Santo, Rio de Janeiro, São Paulo, Santa Catarina, Paraná and Rio Grande do Sul (Melo, 2003; Sampaio et al., 2009; Pimentel and Magalhães, 2014; present work). Remarks. As for M. amazonicum, Ramos-Porto and Coelho (1998) and Ferreira et al. (2010) cited the occurrence of M. carcinus in Piauí but without mention the material examined and locality. This is the first documented record of M. carcinus in the Parnaíba River basin. Macrobrachium carcinus is the most important freshwater species economically and socially in the Brazilian northeast region. Populations of this species are in decline in several Brazilian hydrographic basins due to over-exploitation and habitat loss (Almeida et al., 2008). However, no studies about population estimation quantify the population reduction of this species, which motivated the categorization of this species as Insufficient Data in the last evaluation of the threatened crustacean species of the Brazilian fauna (Mantelatto et al., 2016), although most fishermen agree that this species is threatened in at least some regions (Almeida et al., 2008). In addition, the practice of uncontrolled cultivation of other Macrobrachium species in nonnative areas, with the possibility of species dispersal, may represent a future concern for local biodiversity (Mantelatto et al., 2016). Macrobrachium carcinus is easily recognizable through its short rostrum and the carpus of the second pereopod distinctly shorter than the merus, and with a single, large, triangular tooth on the cutting edges of the dactyl and propodus.	en	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: 1-8, DOI: 10.1590/2358-2936e2018017, URL: https://doi.org/10.1590/2358-2936e2018017
D05BFC048A67FFC8FC16FDB7A173FDAB.taxon	description	(Fig. 5 A – D) Material examined. Brazil, Piauí: Prata Lagoon, 18. xi. 2014, 500 specimens [CZDP (F 2) 0049]. Idem, 18. xi. 2014, 1 male, 4 females (LSZ 027). Distribution. In Brazil, this species has been recorded in the states of Acre, Amapá, Amazonas, Pará, Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, Bahia, Mato Grosso, Espírito Santo, Rio de Janeiro, Minas Gerais, São Paulo, Paraná, Santa Catarina) (Melo, 2003; Pileggi et al., 2013; present work). Remarks. This is the first record of M. jelskii in the Parnaíba River basin. M. jelskii is commonly found in sympatry with M. amazonicum. Here we found both species in Prata Lagoon, though M. jelskii was more abundant than M. amazonicum (cf. material examined). Also, see remarks section regarding M. amazonicum for characters to differentiate between these species.	en	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: 1-8, DOI: 10.1590/2358-2936e2018017, URL: https://doi.org/10.1590/2358-2936e2018017
D05BFC048A64FFC8FF6AFD43A563FC6F.taxon	description	(Fig. 6 A – D) Material examined. Brazil, Piauí: Portinho Lagoon, 25. iv. 2013, 46 specimens [CZDP (F 2) 0050]. Idem, 19. vii. 2013, 38 specimens [CZDP (F 2) 0051]. Idem, 20. ii. 2014, 10 specimens [CZDP (F 2) 0052]. Idem, 04. viii. 2013, 46 specimens [CZDP (F 2) 0053]. Idem, 19. vii. 2013, 2 females (LSZ 075). Distribution. In Brazil, this species has been recorded in the states of Amapá, Piauí, Ceará, Rio Grande do Norte, Alagoas, Sergipe, Bahia, Minas Gerais, Espírito Santo, São Paulo and Santa Catarina (Barros and Braun, 1997; Müller et al., 1999; Melo, 2003; Pimentel and Magalhães, 2014; present work). Remarks. This is the first record of M. olfersii in the lower Parnaíba River basin, although Ferreira et al. (2010) mentioned the occurrence of this species in Piauí when discussing an indeterminate specimen from the Piauí River without a precise locality [material deposited at the Museu Nacional (MNRJ 2574)]. Macrobrachium olfersii can be easily differentiated through its almost straight and relatively short rostrum, and the strong second pair of pereopods with chelae of unequal sizes and gaping fingers and a dense pubescence on the palm and cutting edges.	en	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: 1-8, DOI: 10.1590/2358-2936e2018017, URL: https://doi.org/10.1590/2358-2936e2018017
