Until 1995, the woodcreeper taxon Xiphorhynchus striatigularis (Richmond, 1900) regularly appeared in global and regional checklists of birds. The holotype, a female, was collected in 1894 by F. B. Armstrong at Altamira, in extreme southern Tamaulipas (east-central Mexico), and was sent to the US National Museum, Washington, DC, in a batch of material that also included more than 20 specimens of Ivory-billed Woodcreeper Xiphorhynchus flavigaster Swainson, 1827, from the same place. In his original description, C. W. Richmond noted of his purported new species (originally named Dendrornis striatigularis) ‘...in general similar to D. [= X.] flavigaster, but differs in having the throat and malar patch streaked instead of uniform buff...’ (Richmond 1900: 316).

Winker (1995) noted that the relevant region of Mexico has now been rather well explored ornithologically, but this taxon is still known exclusively from the holotype. He posited that it was probably one of the following: a very rare species, probably now extinct; a hybrid; or an aberrant individual of some other known species. To clarify the identity of this mysterious form, he carried out a detailed morphometric study, and concluded that the striatigularis holotype was most likely an aberrant individual of X. flavigaster, although the possibility of a hybrid origin could not be completely discarded. Another individual collected by Armstrong on the following day in the same area had subsequently been described as X. flavigaster saltuarius Wetmore, 1942, and Winker (1995) proposed that striatigularis be considered ‘a synonym of saltuarius’.

If striatigularis Richmond, 1900, and saltuarius Wetmore, 1942, are considered synonyms, as they are by all of the current major global checklists (Dickinson & Christidis 2014, del Hoyo & Collar 2016, Clements et al. 2023, Gill et al. 2023), it is obvious that the former has priority. However, Winker's wording can be taken to imply the opposite, and that is certainly the version that has entered the literature. Nevertheless, there are good reasons to uphold this reversal of precedence. Of significant practical importance is the fact that, if the two are indeed synonymous, the holotype of striatigularis is an extremely unusual individual, notably different from (apparently) all of the 46 female specimens of X. flavigaster from a range of US museums compared by Winker (1995), and Hellmayr too (in Cory & Hellmayr 1925) emphasised its singularity¹, so it would be a most unsuitable candidate for its primary purpose as a ‘type’ for the taxon currently listed as saltuarius, given that the ‘...type of a nominal taxon provides the objective standard of reference for the application of the name it bears’ (ICZN 1999: Art. 61.1). At the same time, the taxon under discussion has consistently been known as saltuarius since 1942, and the name striatigularis has never been applied to these ‘normal’ birds; a (gratuitous) change of name now would certainly not serve stability of nomenclature. And a third major objection arises from Winker’s conclusions: the possibility of a hybrid origin cannot be fully discounted. Although hybridisation was believed to be extremely rare in suboscine passerines in general (Graves 1992) and was previously unknown between species of Dendrocolaptinae (Marantz et al. 2003, Kirwan & Collar in prep.), more recent molecular studies focused on Amazonian headwater regions have detected intrageneric hybridisation zones among Hypocnemis, Willisornis and Rhegmatorhina antbirds (Thamnophilidae), Dendrocincla, Xiphorhynchus and Glyphorynchus woodcreepers (Furnariidae) and Pipra and Lepidothrix manakins (Pipridae) (Weir et al. 2015, Sampaio et al. 2020, Del-Rio et al. 2021). Several hybrid combinations have been recognised in the last-named family based on both historical specimens and recent genetic research (Hellmayr 1929, Gyldenstolpe 1951, Parkes 1961, Stotz 1993, Haffer 1997, Kirwan & Green 2011, Sampaio et al. 2020), although it should be noted that Pipridae belongs to a cohort (Tyrannida) long separated from antbirds, woodcreepers, etc. (Furnariida), with a quite different breeding system (Fjeldså et al. 2020: 72–73). That most of this research post-dates Winker’s paper does potentially suggest that the hybrid ‘spectre’ is not so easily shaken off. If the holotype of striatigularis were subsequently shown to be of hybrid origin, that name could not be used, under Art. 23.8 (ICZN 1999), so the correct name would of necessity revert to saltuarius.

In view of the above, we consider that the imposition of strict priority in this case would be detrimental, and propose that reversal of precedence be maintained. As the conditions of Art. 23.9.1 are clearly not met, we are preparing an application to the ICZN, under Art. 23.9.3, requesting that reversal of precedence be formally imposed². The purpose of the application will simply be to maintain current usage while incorporating the formal backing required by the Code. While the case is being adjudicated by the ICZN Commission, current usage must be maintained (Art. 23.9.3).