Sphenopsis
Creators: name: Halley, Matthew R.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Aves
Passeriformes
Thraupidae
Sphenopsis

description: The four Sphenopsis species,
including S. ochracea, and two taxa currently classified as subspecies (S. m. castaneicollis, S. f. hanieli), have unique and diagnosable plumage phenotypes, with negligible individual variation within each taxon (Table 2, Figs. 3–7). The only plumage trait with no discernible differences among Sphenopsis taxa was the colour of the uppertail, which was slightly darker than Olive-Brown (Color 28).
Some distantly related Sphenopsis taxa share ventral colour characters to the exclusion of more closely related taxa. For example, S. piurae and S. m. castaneicollis have the same colour throat (Jet Black, Color 89), breast, and vent (Raw Sienna, Color 136), although they are not sister taxa (see Price-Waldman 2019). Similarly, the colour of the vent is identical in S. ochracea, S. m. melanotis and S. f. hanieli (Cinnamon, Color 123A), and also in females of the distantly related Flame-crested Tanager Loriotus cristatus (Linnaeus, 1766), which was formerly placed in Tachyphonus (Burns et al. 2014). The colour of the vent is also similar in females of Fulvous-crested Tanager Tachyphonus surinamus (Linnaeus, 1766). This may explain Sibley’s initial suspicion that the DMNH skins were an undescribed species of Tachyphonus.
Published illustrations of S. ochracea varied greatly in ventral coloration, from slightly darker than Spectrum Yellow (Color 55) in Hilty (2011), to slightly darker than Flesh Ocher (Color 132D) in Isler & Isler (1987). In contrast, specimens of S. ochracea were invariably Tawny Olive (Color 223D) on the throat and belly, and slightly darker than Clay Color (Color 123B) on the breast. Published illustrations have also typically shown some black on the cheeks, and a faint gray supercilium (see Fig. 2), but the three S. ochracea skins from Chiriboga, Ecuador (one female, two males) possess no trace of these characters; and they are faint in ANSP 149722 (Fig. 7) and SMF 58282 (Fig. 1). In photos, the plumage of SMF 58282 appears slightly foxed after nearly 140 years, but its warm brown plumage and greyish crown (like modern specimens of S. ochracea, Fig. 7) lack the greenish tinge of S. frontalis (Fig. 5) and ZMUC 104925, the formerly misidentified S. frontalis skin from Imbabura discussed above (P. Hosner in litt. 2022).
There were subtle differences in size among taxa, all of which exhibited a general pattern of male-biased sexual size dimorphism in the length of the wings and tail, which was not evident in other morphometric traits (Table 3). However, although these data are generally informative about size variation in the genus, sample sizes were too small for a more robust statistical analysis.
Discussion
The scarcity of specimens of S. ochracea in major collections, and problems stemming from the analyses of García-Moreno et al. (2001), have caused much confusion. Most illustrated works portray the external phenotype of S. ochracea inaccurately (e.g., Isler & Isler 1987, Ridgley & Greenfield 2001a, Hilty 2011). The data presented here, including digital photographs of males and females taken under natural light (Figs. 3–7), serve to clarify the distinctiveness of the external morphology of S. ochracea and its closest relatives. Hopefully, this will be sufficient to prevent future researchers from erroneously concluding that overlooked specimens of S. ochracea in collections are undescribed. For clarity of reference, the synonyms and nomenclatural combinations of S. melanotis, S. frontalis, S. piurae and S. ochracea, with lists of specimens examined and brief commentaries under each taxon, are provided in the Appendix.
description: Published as part of Halley, Matthew R., 2022, Taxonomic status of the Western Hemispingus Sphenopsis ochracea (Thraupidae) and a review of species limits in the genus Sphenopsis P. L. Sclater, 1861, pp. 209-223 in Bulletin of the British Ornithologists' Club 142 (2) on pages 216-217, DOI: 10.25226/bboc.v142i2.2022.a5, http://zenodo.org/record/12535806