Synallaxis omissa, E. J. O. Hartert, 1901

Stopiglia, Renata, Barbosa, Waleska, Ferreira, Mateus, Raposo, Marcos A, Dubois, Alain, Harvey, Michael G, Kirwan, Guy M, Forcato, Giovanna, Bockmann, Flavio A & Ribas, Camila C, 2022, Taxonomic challenges posed by discordant evolutionary scenarios supported by molecular and morphological data in the Amazonian Synallaxis rutilans group (Aves: Furnariidae), Zoological Journal of the Linnean Society 195 (1), pp. 65-87 : 81

SYNALLAXIS OMISSA E.J.O. HARTERT, 1901

Synallaxis omissa E.J.O. Hartert, 1901: 71

(holotype AMNH 523598 , adult female from Pará , Brazil, examined by us; see Remarks 4, 5 and 6 for comments) .

Diagnosis: Synallaxis omissa differs from S. rutilans , S. amazonica , S. caquetensis and S. dissors in having the forehead, supercilium and face Vandyke brown (221) without any trace of rufous.

Description: Throat sepia (119); breast and abdomen hair-brown (119a) with or without cinnamon (39) elements; flanks olive brown (28) varying individually to hair-brown (119a); rectrices sepia (119); back hairbrown (119a) with variable traces of amber (36); crown, forehead, supercilium and face Vandyke brown (221); wing-coverts amber (36); remiges Vandyke brown (121); bill length 12.3–15.1 mm; bill depth 4.0– 5.1 mm; wing length 54.9–64.9 mm; tail length 58.0– 74.5 mm, with ten rectrices (see Tables 7, 8).

Distribution: Synallaxis omissa is entirely allopatric with S. rutilans , S. amazonica , S. caquetensis and S. dissors , being restricted to the area east of the right bank of the Tocantins River, in south-eastern Pará and northern and western Maranhão, Brazil. The geographic range of the species is restricted to the Belém AE [as defined by Haffer (1969)] and all records of S. rutilans in the state Maranhão are attributable to S. omissa . Distribution represented in Figures 1 and 4 by yellow colour of the Belém AE.

Remarks 4: According to E.J.O. Hartert (1901), the holotype of Synallaxis omissa, AMNH 523598, an adult female, was collected by Joseph Beal Steere (1842–1940), on 19 July 1897. LeCroy & Sloss (2000) highlighted that the correct year of collection was 1879 [not 1897, as reported by E.J.O. Hartert (1901)].

Remarks 5: The original description of S. omissa cited the type locality as Pará, Brazil (E.J.O. Hartert, 1901). Subsequently, Paynter & Traylor (1991: 66) considered this to be more precisely defined as ‘Belém’, and designated the coordinates 0127/4829 (USBGN) for the precise location. Restriction of the type locality of S. omissa to Belém, Pará, was corroborated by Papavero et al. (2008: 133) and is consistent with the species distribution east of the right bank of the Tocantins River based on the specimens we studied.

Remarks 6: Peters (1951: 91) stated that ‘The majority of the specimens of this race lack any trace of rufus on the head and underparts; occasional specimens however are coloured exactly like S. r. rutilans ’, and in fact, as previously reported, the underparts of S. rutilans and S. omissa can appear similar in respect of those specimens of the latter with cinnamon (39) colour on the breast and abdomen. However, S. omissa is diagnosed by the plumage of the head and contra Peters (1951), among all of the 317 specimens analysed by us (including those in the Museum of Comparative Zoology, where Peters was curator while preparing his Check-list of birds of the world in 1931–52), we have not located any individual of S. omissa with the coloration of S. rutilans (or S. dissors and S. caquetensis ) on the head. In other words, none of the specimens showed any trace of amber (36) or cinnamon (39) on the head and face, whereas all individuals of S. rutilans , S. dissors and S. caquetensis analysed by us were well marked in this respect. It is important to note that S. omissa , although considered a subspecies of S. rutilans , has been distinguished to some extent as a unique biological entity by use of a unique vernacular name. Whereas the English name of all other taxa within the S. rutilans group is ruddy spinetail, sooty spinetail was used for S. omissa by del Hoyo & Collar (2016).

Figures

Figure 1. Map showing the distribution of sequenced individuals, phylogenetic time tree and plumage analyses for the Synallaxis rutilans group. The areas of endemism recognized by Silva et al. (2005) are highlighted on the map, and distribution points are numbered in accordance with individuals in the tree. The phylogenetic time tree is based on 1539 bp of concatenated ND2 and COI genes. Posterior probability values and the 95% HPD are indicated at each node. Thr, throat; Rec, rectrices; For, forehead; Sup, supercilium; Fac, face; Win, wing-coverts; Rem, remiges; 1st, first colour (main colour); 2nd, second colour (variation ±); 36 (e.g.), colours in Smithe’s catalogue; *, specimen damaged or immature; **, specimen analysed without Smithe’s catalogue; MPEG A, spirit collection specimen; dark grey circles in map and patches in table, specimens with grey plumage pattern; light grey circles and patches, specimens with olive plumage pattern; black circles and patches, specimens with rufous plumage pattern; purple star, type locality of S. r. dissors; red star, type locality of S. r. caquetensis; red star with white spot, type locality of S. r. confinis; blue star, type locality of S. r. amazonica; blue star with a white spot, type locality of S. r. tertia; orange star, type locality of S. r. rutilans; yellow star, type locality of S. r. omissa.

Figure 4. Plumage distribution and geographic variation in the Synallaxis rutilans group. Dark grey circles, specimens with grey-patterned plumage; pale grey circles, specimens with olive-patterned plumage; black circles, specimens with rufous-patterned plumage. Concerning intermediate individuals, any specimen with rufous present on the upperparts was classified in the ‘specimens with rufous-patterned plumage’ group. *Illustrations of birds with the typical plumage of: S. caquetensis (on the left); S. dissors (centre above); S. omissa (right). Area of endemism (AE) and distribution of species of the Synallaxis rutilans group: purple, Guiana EA, S. dissors; red, Napo EA, S. caquetensis; orange, Xingu EA, S. rutilans; yellow, Belém EA, S. omissa; and green, Inambari EA, blue, Rondônia EA and turquoise, Tapajós EA, S. amazonica. *Illustrations from del Hoyo J, Elliott A, Sargatal J, Christie DA, de Juana E, eds. 2017. Handbook of the birds of the world alive. Barcelona: Lynx Edicions (retrieved on 10.11.2017 from http://www.hbw.com).