Little Nightjar

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Though clearly deriving his texts on Paraguayan nightjars strongly from the work of Azara, Bertoni (1900) employed the names Caprimulgus sphenurus Vieillot, 1817 for a bird he called the “ Yvyyahú anónimo ” and Caprimulgus epicurus Vieillot, 1817 for a bird he called the “ Yvyyahú de cola extraña ”, thereby linking both directly with Azara’s original work. This is a crucial step because it represented a post- 1899 employment of these otherwise forgotten names and thereby validates them for usage (ICZN 1999: Art. 23.9.1.1). Caprimulgus sphenurus Vieillot, 1817 (p. 243) has priority over both Caprimulgus parvulus Gould, 1837 and Caprimulgus epicurus Vieillot, 1817 (p. 243), and is thus an available name for the Little Nightjar. A decade after Vieillot (1817), two other names were also been proposed for Azara’s two nightjars by Merrem (1826), Caprimulgus azarae for No. 316 and C. cordicilla for No. 315, and these also enter into the synonymy of Little Nightjar. Note that the usage of the name “ Yvyyahú de Azara ” Caprimulgus Azarae Bertoni, 1900 for a “ new species ” of nightjar from eastern Paraguay is not in the sense of Merrem, 1826 and represents a junior homonym. Caprimulgus Azarae Bertoni, 1900 was not adequately described, the author stating simply that it “ has the form of the previous species ” in reference to Chordeiles minor (Forster, 1771), and that it “ shows differences in color which I do not consider it necessary to detail here ”. With no other keys to its identity, Caprimulgus Azarae Bertoni, 1900 must be considered a nomen dubium. The ICZN states on its preamble that “ priority of publication is a basic principle of zoological nomenclature; however, under conditions prescribed in the Code its application may be modified to conserve a long-accepted name in its accustomed meaning. When stability of nomenclature is threatened in an individual case, the strict application of the Code may under specified conditions be suspended by the International Commission on Zoological Nomenclature. ” Therefore, given the long history of usage of the current name Setopagis parvula (Gould, 1837) and the stated aim of the ICZN Code to maintain stability, it is recommended that the following synonyms of this name be suppressed as nomina oblita and current usage be maintained (ICZN 1999: Recommendation 23 A).