There are six subspecies currently recognized. Two specimens from Ceará (northeastern Argentina) could possibly be subspecies, yet to be described (Dickerman 1988).
septentrionalis, described as Nannochordeiles pusillus septentrionalis (Hellmayr 1908); type locality Maipures, Rio Orinoco, Venezuela [= Colombia, fide Dickerman 1988]
Occurs from eastern Colombia east to Guyana, and probably south to western Surinam. Possibly western Brazil.
"Similar to nominate pusillus but smaller ... more finely barred ventrally than other subspecies, with undertail coverts white and without barring. Finely vermiculated above, with smaller black areas, especially on the crown, than esmeraldae; much less deeply coloured than saturatus; darker than the Parahyba population (xerophilus), and less reddish than the Marauhao population (novaesi)" (Dickerman 1988).
esmeraldae, described as Chordeiles pusillus esmeraldae Zimmer and Phelps 1947; type locality Esmeralda, Territorio Amazonas, Venezuela
Occurs from southern Venezuela (Amazonas) south to Tocantins, Brazil, and probably occurs in eastern Colombia on the Río Negro (Dickerman 1988).
"Ventrally, entirely and heavily barred with black, including the undertail coverts; saturatus is equally heavily barred ventrally but has unbarred white undertail coverts. Dorsally feather edgings paler than in saturatus ... Larger than septentrionalis, but smaller than pusillus" (Dickerman 1988).
Robbins et al. (2004) commented that the distributions of septentrionalis and esmeraldae, as outlined by Dickerman (1988), "make no sense biogeographically", unless perhaps some populations are migratory. As noted by Robbins et al. (2004), "The type localities [of septentrionalis and esmeraldae] are only c. 250 km apart and a specimen identified by Dickerman as belonging to septentrionalis ... was taken within 100 km of the type [locality] of esmeraldae. Clearly, more material is needed to determine if some populations are migratory".
pusillus, described as Chordeiles pusillus Gould 1861; type locality "supposed to be from Bahia". Dickerman (1988) restricted the type locality to Rio Thesouras, Goiás, Brazil.
Occurs in northeastern Brazil (Bahia and Goiás; possibly also São Paulo) (Dickerman 1988). It is not known whether a record from northeastern Argentina (Krauczuk 2000) refers to pusillus, saturatus, or to an undescribed taxon.
See Detailed Description. Similar to septentrionalis, but slightly smaller, and "the belly is more extensively barred with sooty grey; the bars are somewhat wider" (Dickerman 1988).
xerophilus, described as Chordeiles pusillus xerophilus Dickermann 1988; type locality Santa Luiza, Paraiba, Brazil
Extreme northeastern Brazil, in Paraíba and perhaps Bahia (Dickerman 1988). Two specimens from Ceará (northeastern Brazil) are similar, but not identical to, xerophilus, and possibly represent an undescribed subspecies (Dickerman 1988).
This is the palest subspecies. Also, the dusky bars on the belly are less distinct than in other subspecies; undertail coverts white and unbarred (Dickerman 1988).
novaesi, described as Chordeiles pusillus novaesi Dickermann 1988; type locality Flores, Maranhao [Maranhão], Brazil.
Occurs in Maranhão and Piauí, northeastern Brazil.
"The most richly coloured subspecies dorsally ... (ie. darker coloured than septentrionalis and pusillus, but less dark than saturatus). Barring on undertail coverts weak or absent. Smaller than pusillus" (Dickerman 1988).
saturatus, described as Chordeiles pusillus saturatus Pinto and Camargo 1957; type locality "Sul do Para, al este do Tapajos", Brazil
Occurs in southern Pará and Mato Grosso, Brazil (Dickerman 1988); records from eastern Bolivia presumably are this subspecies (Cleere 1988).
"Dorsally the most sooty coloured of all the subspecies, with dark cinnamon feather edgings; heavily barred ventrally, except for undertail coverts, which are white. Larger than esmeraldae" (Dickerman 1988).