Elliotomyia, Stiles & Remsen, 2019

Stiles, F. Gary & Remsen, J. V., 2019, The generic nomenclature of the Trochilini: a correction, Zootaxa 4691 (2), pp. 195-196 : 195-196

Elliotomyia , gen. nov.

Included species. This genus includes two currently recognized species: Trochilus chionogaster Tschudi, 1846 and Leucippus viridicauda Berlepsch, 1883 . Both occur at middle elevations on the eastern slope of the Andes, mainly between 1000–3000m. Two subspecies are recognized in E. chionogaster : the nominate in northern and central Peru and hypoleuca Gould, 1846 from extreme southern Peru to northern Argentina. Elliotomyia viridicauda is limited to central Peru, where it is locally sympatric with E. c. chionogaster ( Schuchmann 1999) . Where they occur together (in the Marañón River watershed), viridicauda is found mainly in the canopy and borders of humid forest, whereas chionogaster prefers drier, more open, shrubby vegetation ( Schulenberg et al. 2009), as does the allopatric hypoleuca ( Robbins et al. 2013). All three taxa have uniform bronzy-green upperparts, white underparts speckled or shaded with bronzy-green laterally, and black bills but with the basal half of the mandible reddish; they are similar in size (ca. 4.8–6.2g, bills averaging 20–23mm, wing chords averaging 55–59mm, tails 28–31mm); males tend to have shorter bills but longer wings and tails. The taxa differ most notably in tail color and pattern. The tail of viridicauda is mostly green above and dull, dark grayish-bronze below, but the inner webs of most rectrices of chionogaster are broadly whitish to pale gray basally; the tail of hypoleuca has more extensive white on the outer rectrices, which are rather boldly white-tipped in the females. Robbins et al. (2013) suggested that hypoleuca may merit species rank largely based upon its vocalizations, but until genetic data and a detailed analysis of sonograms become available, we retain it as a subspecies here. We designate chionogaster as the type species of Elliotomyia .

Etymology. The genus name honors Daniel Giraud Elliot for his important early contributions to clarifying the generic taxonomy of the hummingbirds. To this eponym, we add the suffix “myia” (Greek for “fly”), which has been used several times elsewhere to denote the small size of the hummingbirds.

Diagnosis. Elliotomyia may be diagnosed genetically from various other genera formerly presumed to be closely related ( Stiles et al. 2017a). Differences in plumage and morphology of Elliotomyia from these are relatively subtle, but taken together with biogeography also permit diagnosis. Both Elliotomyia species were included in Leucippus in the past, but were transferred to Amazilia due to plumage similarities ( Zimmer 1950; see Stiles et al. 2017a, b). However, this “green-and-white” style of plumage is subject to widespread homoplasy; moreover, the similar species formerly placed in Amazilia, Agyrtria or Agyrtrina are mostly lowland species of northern and eastern South America. All share the bicolored bill with Elliotomyia , but most have brighter white underparts and more emerald-green upperparts; some such as franciae (Bourcier & Mulsant) and brevirostris (Lesson) also are strongly bronze on the rump and tail; Middle American candida (Bourcier & Mulsant) is considerably smaller and entirely bronze-green above and on the tail, with an indistinct dusky terminal band. The only Andean species, franciae , has clean white underparts and bright blue (males) or blue-green (females) crown and nape. Genetic data support placement of all of these species in different genera, including Chrysuronia, Chlorestes or Uranomitra ( Stiles et al. 2017a) .

The species formerly placed in Leucippus are now allocated to several genera based on genetic data, and all differ from Elliotomyia species in their all-black bills. The genus Leucippus as currently circumscribed (cf. Stiles et al. 2017a) includes only L. fallax (Bourcier) , restricted to the arid northern coastal lowlands of Colombia and Venezuela; its uniform buffy underparts and outer rectrices broadly tipped with dull white are distinctive. Compared with Elliotomyia , the two species of Thaumasius are duller, more brownish-olive above; taczanowskii Sclater has mostly grayish-drab underparts and a paler throat specked with dusky or green, whereas baeri (Simon) has uniform, dull buffy-brown underparts and outer rectrices broadly tipped with dull white. Both occur in arid matorral vegetation at lower elevations, taczanowskii in the upper Urubamba valley and baeri in the Pacific Tumbesian region. Taphrospilus hypostictus (Gould) is considerably larger than the species of Elliotomyia , with whitish underparts strongly spotted with green except on the lower abdomen; it inhabits the interior of humid forest on the eastern Andean slopes from Bolivia to southern Colombia, mostly at lower foothill elevations. Talaphorus chlorocercus (Gould) is darker, duller green above and grayish below, sparsely speckled with brighter green on the throat and sides; its lateral rectrices have largely gray bases, a dusky subterminal band and gray tips; it occurs in the upper Amazonian lowlands on the banks and islands of larger rivers ( Schulenberg et al. 2009). In sum, the genetic and plumage differences correlate with ecological and distributional features distinguishing all of these genera.