SPECIES

Rose-throated Becard Pachyramphus aglaiae Scientific name definitions

Jon S. Greenlaw
Version: 1.0 — Published March 4, 2020
Text last updated February 14, 2014

Systematics

Systematics History

Editor's Note: This article requires further editing work to merge existing content into the appropriate Subspecies sections. Please bear with us while this update takes place.

Geographic Variation

Measurements of wing chord, bill length (exposed culmen), and bill width at the nostril are compiled in Table 2 (from Webster 1963). Full sample information permitted calculation of 95% confidence limits based on a Student's t-distribution for small sample sizes and comparison of sample means using standard errors representing the eight subspecies now recognized (Snow 1979) across the geographic range of the species. The overall distribution is spread across Middle America from the United States border with Mexico southeastward to Costa Rica or western Panama. No clinal variation in any of the three mensural characters is evident across the full northwest-southeast geographic gradient of the range. Rather, variation forms regional mosaic patterns in which wing chord represents one pattern and the two bill dimensions represent another. For example, culmen length is longer in Atlantic coast populations of northern Mexico than those along the Pacific coast. The becards isolated on Tres Marías Islands off western Mexico apparently are the smallest-billed and shortest-winged (Table 2), but small sample size means the population statistics are unreliable. The geographic pattern of wing chord length conformed between sexes. Longest-winged populations on the mainland were in northeastern Mexico (P. a. gravis), south central Mexico (P. a. aglaiae), and the Pacific lowlands from El Salvador to Costa Rica (P. a. latirostris). These long winged subspecies have significantly longer wing chords than the shortest winged subspecies in the Yucatán Peninsula (P. a. yucatanensis) and the Caribbean coastal region from central Belize to Costa Rica (P. a. hypophaeus). In contrast, becards with the longest and widest bills are on the Yucatán Peninsula and adjoining southern Mexico and western Guatemala (P. a. sumichrasti), and in northeastern Mexico. Mean bill dimensions in these populations are significantly longer than those in populations having the smallest bills in western and south-central Mexico (P. a. albiventris, P. a. aglaiae). No evidence suggests that width of the modified ninth primary in adult males varies geographically within P. aglaiae (Webster 1963), or between P. aglaiae and P. homochrous (One-colored Becard) in southeastern Central America (contra Ridgway 1907).

Variation in color and pattern in both sexes is notable across the range of the species. This summary draws heavily on Webster (1963). Color on throat in males, upperparts and underparts in both sexes, crown in females, and hindneck collar development in females are notably variable among subspecies. Overall, male and female becards at the extremes fall into dark- and pale-bodied groups. The darkest males have little or no red on the throat, while pale birds have a distinctive rose, magenta, or ruby-colored throat patch that often extends to the upper breast. P. a. sumichrasti and P. a. hypophaeus are the darkest (quite blackish in hypophaeus) birds, and P. a. albiventris, possibly P. a. insularis (specimens worn), P. a. yucatanensis, and P. a. latirostris are the palest. P. a. gravis and P. a. aglaiae are intermediate but noticeably darker than P. a. albiventris. Dorsal body color in males varies prominently, from brownish or slaty black to light gray. The palest populations occupy the driest, most arid regions and the darkest the most humid areas, thus providing an example of Gloger's biogeographic 'rule', which relates feather melanin pigmentation to climate (Webster 1963, Burtt and Ichida 2004).

Among females, ground color varies from darker orange tawny to very pale whitish tawny above, and from dark gray with a reddish brown tone to pale rusty. Individual females may be grayer or redder above in some populations. Cap color in females varies from rufescent brown to blackish gray to black both within and among populations (e.g., P. a. gravis; Oberholser 1974). In most females, a tawny hindneck collar folds around onto the sides of the neck, setting off the color of the crown from that of the back. The collar is often quite distinct, as in P. a. albiventris and P. a. aglaiae, but in P. a. sumichrasti, P. a. yucatanensis, and P. a. hypophaeus it may be indistinct to absent. In P. a. gravis and P. a. latirostris, collar distinctness is quite variable. Some females may show a faint suffusion of pink in fresh plumage on the throat, especially in northeastern populations.

Subspecies


SUBSPECIES

Pachyramphus aglaiae aglaiae Scientific name definitions

Distribution

highlands of S Mexico (C and S Guerrero E to S Oaxaca and WC Veracruz).

SUBSPECIES

Pachyramphus aglaiae albiventris Scientific name definitions

Distribution

SW USA (SE Arizona) and W Mexico (Sonora and Pacific slope from S Sinaloa S to N Guerrero, also up river valleys E to Chihuahua, Zacatecas and Morelos).

SUBSPECIES

Pachyramphus aglaiae gravis Scientific name definitions

Distribution

coastal region of NE Mexico (Nuevo León and Tamaulipas S to San Luis Potosí); casual in extreme S USA (S Texas).

SUBSPECIES

Pachyramphus aglaiae hypophaeus Scientific name definitions

Distribution

Caribbean slope from C Belize and C Guatemala S to Costa Rica.

SUBSPECIES

Pachyramphus aglaiae insularis Scientific name definitions

Distribution

Tres Marías Is, off W Mexico (Nayarit).

SUBSPECIES

Pachyramphus aglaiae latirostris Scientific name definitions

Distribution

Pacific slope from N El Salvador S to NW Costa Rica and (rare) Panama.

SUBSPECIES

Pachyramphus aglaiae sumichrasti Scientific name definitions

Distribution

SE Mexico (C Veracruz S to N and SE Oaxaca, E to Campeche) and W Guatemala.

SUBSPECIES

Pachyramphus aglaiae yucatanensis Scientific name definitions

Distribution

Yucatán Peninsula (Yucatán, N Campeche, N Quintana Roo).

Related Species

The systematic position of becards and tityras has been notably tentative and unsettled until recently (Fitzpatrick 2004, Barber and Rice 2007, Chesser et al. 2011). Historically, the group has been regarded as unusual cotingas (Cotingidae) or as odd tyrant flycatchers (Tyrannidae). Early workers placed P. aglaiae and several similar species in the genus "Platypsaris"(e.g., Ridgway 1907, Webster 1963), but they were moved to Pachyramphus to join the other becards by Snow (1979). Phylogenetic analyses of nuclear and mitochondrial DNA find the becards, tityras, and their allies form a monophyletic group that is best represented in the separate family Tityridae (e.g., Chesser 2004, Tello et al. 2009, Chesser et al. 2011).

The Rose-throated Becard is polytypic with eight currently recognized subspecies (Snow 1979). Species limits have been controversial and have both excluded (Ridgway 1907, Hellmayr 1929) and included (Webster 1963) similar P. homochrous (One-colored Becard) that is widespread in the Neotropics from Panama southward. No geographic contact occurs between the two taxa, which are regarded now as separate species. The subspecies, with brief diagnoses based on adults and modified from Webster (1963) Monroe (1968), and Mobley (2004) in relation to nominate P. aglaiae and selected similar subspecies, are listed next from north to south (Figure 5). Terminology is as follows: "above" and "dorsum" are upperparts of the body; "below" and "ventrally" are underparts of the body; nominate or typical form is P. a. aglaiae. I examined original descriptions in each case.

P. a. gravis (van Rossem, 1938) (Platypsaris aglaiae gravis, type locality Alta Mira [= Altamira], Tamaulipas, Mexico). Northeastern Mexico, with irregular occurrences near border in Texas, to northern Veracruz. Males, intermediate between dark- and pale-bodied subspecies: similar to nominate aglaiae; females more brownish red on back and with less distinct hindneck collar, buffy neck, throat, and underparts without reddish overtone. Overall, longest-winged of all subspecies.

P. a. albiventris (Lawrence, 1867) (Hadrostomus albiventris, type locality Western Mexico, Plains of Colima). P. a. richmondi (van Rossem 1930) is a synonym. Northwestern Mexico, irregular occurrence in Arizona borderland, south through the interior of eastern Sonora and along the Pacific lowlands to northern Guerrero, and inland along major river valleys. Males: paler and grayer than all other subspecies, throat of male closer to ruby or magenta (Webster 1963). Females: also palest and grayest of all subspecies.

P. a. insularis (Ridgway, 1887) (Platypsaris insularis, type locality Tres Marias Islands, western Mexico [Nayarit]). Occurs only on Isla María Madre (Nelson 1899, Webster 1963). Known from a handful of worn specimens. Apparently short winged and small billed, another pale bodied subspecies, perhaps slightly grayer above and below in males and a little browner ventrally and darker dorsally in females than in nominate birds (Webster 1963). Most similar to P. a. yucatanensis, but bill smaller.

P. a. aglaiae Lafresnaye, 1839 (Pachyrhynchus Aglaiae, type locality "Mexico," restricted to vicinity of Jalapa [= Xalapa], Veracruz, Mexico by Nelson [1897, 1899]). Southern Mexico from interior highlands to Pacific coast. Males, intermediate between dark- and pale-bodied subspecies: glossy black crown contrasting with gray to slaty gray back, paler gray below, and well-developed rosy pink patch on lower throat and upper breast; females: slaty gray to brownish black crown, variably distinct buffy hindneck collar separating darker crown from grayish rust to reddish brown back, more buffy with faint reddish tone below. See Detailed Description.

P. a. sumichrasti (Nelson, 1897) (Platypsaris aglaiae sumichrasti, type locality Otatitlan, Vera Cruz [= Otatitlán, Tlacotalpán, southern Veracruz, Mexico; Snow 1979]). Southern Veracruz and south half of Yucatán Peninsula to the Pacific coast across the Isthmus of Tehuantepec, Oaxaca, and southeast to western Guatemala, where it intergrades into northern El Salvador with P. a. latirostris (Dickey and van Rossem 1938, Monroe 1968). Most similar to P. a. hypophaeus, which is paler on average and has little or no red on throat. Males: among darkest of the subspecies, much darker above and below than nominate populations, and unlike typical form (but see below), but like hypophaeus, no contrast between top of head and upperparts of body. Nelson (1897) characterized the color of top and sides of head, neck, and back as "uniform glossy black," dark ashy on rump. Webster (1963) described the dorsum as brownish black (some individuals having a grayer tone), and paler "smoky dark gray" below. Only in the Guatemalan central highlands does P. a. sumichrasti approach typical aglaiae in having a contrast between a paler back and black crown (Griscom 1932). Red patch on throat tends more to a violet hue, as in P. a. hypophaeus. Females: Rusty tones on dorsum darker, with stronger brown shade, than in P. a. aglaiae, while underparts darker orange tawny. See Webster (1963) for comparisons with other subspecies.

P. a. yucatanensis (Ridgway, 1906) (Platypsaris aglaiae yucatanensis, type locality Yucatán). Northern half of mainland Yucatán Peninsula; one early record from Isla Cozumel perhaps accidental, but a breeding attempt was reported in 2000 (Carmody 2012) following discovery of another pair in 1996 (Howell 2004), and putative record from Isla Holbox possibly mis-localized (Paynter 1955). An intermediate pale bodied subspecies most similar to P. a. aglaiae, P. a. gravis, and P. a. latirostris. Relative to nominate form and P. a. gravis, has paler underparts; throat patch more ruby-toned than pink or magenta as in P. a. aglaiae; shorter-winged than gravis; browner below than latirostris and always has red throat patch that is often missing in latirostris. Females: more or less similar to P. a. aglaiae, but averaging paler below, some approaching pale whitish tawny of P. a. albiventris (Webster 1963).

P. a. hypophaeus (Ridgway, 1891) (Platypsaris aglaiae hypophaeus, type locality San Pedro Sula, Honduras). Caribbean coast and adjoining highland slopes from Belize and northeastern Guatemala to west-central Costa Rica. A dark-bodied subspecies well-separated from the paler nominate subspecies in southern Mexico. Geographic variation in populations of P. aglaiae where three subspecies meet (Figure 5) in northern Central America remain poorly understood (Monroe 1968). P. a. hypophaeus is geographically close to paler P. a. latirostris, with which it should be compared, but former perhaps is as dark as P. a. sumichrasti (Monroe 1968). Males: notably more blackish above with little or no contrast between the crown and back, and also blackish below except paler on abdomen, while overall pale gray below in latirostris; throat if colored at all is restricted and deep purplish red rather than pale pink as in latirostris. Females: darker, more tawny ventrally than latirostris, and darker, stronger brownish rufous dorsally.

P. a. latirostris Bonaparte, 1854 (Pachyramphus latirostris, type locality "Nicaragua," restricted by J. T. Zimmer [in Snow 1979] to Chinandega, western Nicaragua). Pacific slope of Central America from northern El Salvador to southwestern Costa Rica and perhaps western Panama (see below). A pale-bodied form that may be effectively isolated by high elevations of the Central American interior cordilleras from P. a. hypophaeus on the Caribbean coast; no known intermediates (in Nicaragua) between the two subspecies (T.R. Howell in Martínez-Sánchez and Will 2010). Males: black crown contrasts with slaty gray dorsum, which is paler than in both P. a. aglaiae (in which contrast also occurs) and P. a. hypophaeus (no contrast). Variation occurs within latirostris, with more northern males averaging darker than more southern males; white-throated males are absent in El Salvador while such males are increasingly common southward in Nicaragua and Costa Rica (Webster 1963). If the red throat is present at all in latirostris (more prevalent in northern males), it is pale rose rather than purplish red as in hypophaeus. Females: above tawny rufous, but paler rufous tones than in either P. a. aglaiae or P. a. hypophaeus; below buff to pale tawny or cinnamon, similar to nominate aglaiae, but paler than in hypophaeus. Hindneck collar is less distinct in latirostris than in nominate aglaiae and similar to that of hypophaeus.

Fossil History

No fossils known.

Recommended Citation

Greenlaw, J. S. (2020). Rose-throated Becard (Pachyramphus aglaiae), version 1.0. In Birds of the World (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.rotbec.01