Systematics

Phaethornis longuemareus is monotypic. The proposed subspecies imatacae (Phelps and Phelps 1952), known from only a few specimens, is regarded as based on hybrids between Phaethornis longuemareus and Streak-throated Hermit (Phaethornis rupurumii) (Hinkelmann 1996).

Described as Trochilus Longuemareus Lesson 1832; type locality Cayenne

Formerly Phaethornis longuemareus was classified as a polytpic species with a distribution extending from Mexico south to southeastern Brazil (e.g. Peters 1945, Zimmer 1950). Hinkelmann and Schuchmann (1997), based on a phylogenetic analysis of morphology (primarily plumage pattern), recognized most of these taxa as separate species (Phaethornis striigularis Stripe-throated Hermit, Phaethornis aethopygus Tapajos Hermit, Phaethornis atrimentalis Black-throated Hermit, and Phaethornis idaliae Minute Hermit), and considered longuemareus to be a monotypic species confined to northeastern South America. Almost all subsequent authors have followed the taxonomy of Hinkelmann and Schuchmann (1997). Recognition of multiple species in this complex also is supported by phylogenetic analysis of DNA sequence data, from both mitochondrial and nuclear genes (McGuire et al. 2007, 2009, 2014). With the caveat that these studies did not sample all relevant taxa (taxa missing include Phaethornis aethopygus and Phaethornis idaliae), longuemareus belongs to a clade that also includes Phaethornis squalidus (Dusky-throated Hermit), Phaethornis rupurumii (Streak-throated Hermit), and Phaethornis nattereri (Cinnamon-throated Hermit), whereas Phaethornis atrimentalis is sister to Phaethornis ruber (Reddish Hermit), and Phaethornis striigularis is sister to Phaethornis griseogularis (Gray-chinned Hermit) (McGuire et al. 2014).

Phaethornis longuemareus reportedly has hybridized with Phaethornis rupurumii (see Geographic Variation).

Phylogenetic analysis of DNA sequence data, from both mitochondrial and nuclear genes, reveals that hummingbirds (Trochilidae) constitute nine major clades, comprising the hermits, mangos, Patagona, topazes, coquettes, brilliants, mountain-gems, bees, and emeralds (McGuire et al. 2007, 2009, 2014). Phaethornis is a member of the hermit clade (McGuire et al. 2007, 2009, 2014). Other genera that belong to the hermit clade are Eutoxeres, Ramphodon, Glaucis, and Threnetes; Glaucis and Threnetes are sister to one another, and Phaethornis is sister to Glaucis + Threnetes (McGuire et al. 2007, 2009, 2014).