Hirundo leucopyga Pallas, 1811

Mlíkovský, Jiŕí & Frahnert, Sylke, 2009, Nomenclatural notes on Neotropical swallows of the genus Tachycineta Cabanis (Aves: Hirundinidae), Zootaxa 2209 (1), pp. 65-68 : 65-66

“ Hirundo leucopyga Pallas, 1811 ”

Brooke (1974: 131) suggested that Pallas (1811: 539) described an Asian swift species as Hirundo leucopyga . However, Pallas never created such a name. In his Latin text, Pallas (1811: 538-541) mentioned a white-rumped variety of the Common Swift Hirundo (= Apus ) apus Linné, 1758 , which he called (p. 538) “β Hirundo (Cypselus) fusco-nigricans, uropygio albo” (his italics). He further referred to this variety five-times on pp. 539–541. First (p. 539), he noted that the Common Swift was seen in Dauria “cum varietate β leucopyga mixta” (his italics), i.e. “in mixed [flocks] with the whiterumped β -variety ”. Second (p. 539), he remarked “Haesitavi diu, an leucopygam β varietatem pro distincta specie haberem” (his italics), i.e. “I hesitate to recognize the white-rumped β- variety as a distinct species” (and added reasons why he decided so). Third, on p. 540 he gave a detailed description of this variety, referring to it solely as to the “ Varietati β” (his italics), not using the word ‘leucopygus’. In further text, Pallas (1811) simply referred to this bird as to “β” (p. 540 and 541). It is evident from these passages that Pallas (1811) used the word ‘leucopygus’ neither in the sense of a species-group name, nor as an infrasubspecific name, and that he had no intention of describing the variety as a taxon, which he explicitly stated.

The first author to believe that Pallas (1811) used ‘leucopygus’ as a name for a variety seems to have been Eversmann (1851: 573; reprinted in Eversmann 1853: 290), who wrote ”Ausser diesem Cypselus [= Apus apus (Linné) ] kommt im Ural keine andere Spezies vor, auch nicht die Var. β leucopyga Pall. ” (his italics), i.e. “No other species occurs in the Urals in addition to this Cypselus [= Apus apus (Linné) ], not even the var. β leucopyga Pall. ”. Somewhat later, Jerdon (1877: 180) remarked in a similar vein: “and one of the two is probably Pallas’ var. B, (leucopyg,) [sic!] of Hir. apus .” Herewith, Eversmann (1851: 573) became the author of the name, published as [ Cypselus Apus ] var. leucopyga (cf. ICZN 1999, Art. 45.6.4.), defining it via reference to “Pall.” [= Pallas 1811] (cf. ICZN 1999, Art. 12.2.). Some subsequent authors attributed the name to Pallas (1811) without explanation, listing it in the synonymy of Apus pacificus (Latham, 1801) (e.g. Taczanowski 1876: 133, Hartert 1892: 448, 1897: 86, 1912: 841, Buturlin 1936: 175, Bent 1940: 305, Ptušenko 1954: 636, Stepanân 2003: 328). If northern populations of Apus pacificus (Latham) , including those living in Dauria (which is the type locality of Cypselus apus leucopygus Eversmann ), are recognized as a distinct subspecies, as tentatively suggested by Hartert & Steinbacher (1935: 355) and accepted by Ivanov (1953: 331), then they should bear the name Apus pacificus leucopygus (Eversmann) .

Hirundo leucopyga Pallas, 1811 , thus does not exist, and Cypselus apus leucopygus Eversmann, 1851 , does not preoccupy Hirundo leucopyga Meyen, 1834 . The names of white-rumped swifts of Asia thus have no bearing on the nomenclature of Tachycineta swallows (contra Brooke 1974).