Species limits in Syma kingfishers using plumage, morphometric and bioacoustic analyses

Abstract

The genus Syma Lesson, 1827 is unanimously considered to comprise two very similar, altitudinally-segregated species in the New Guinea bioregion: Yellow-billed Kingfisher S. torotoro and Mountain Kingfisher S. megarhyncha. One taxon, S. t. ochracea of the D’Entrecasteaux Archipelago off eastern New Guinea, has recently been suggested as an independent species, but the evidence has so far remained unassembled. Here, I combine morphometric and plumage data of 127 museum specimens (including 34 of S. t. ochracea), and bioacoustic data from 52 sound recordings to analyse species limits in this complex. Morphologically, S. t. ochracea differs distinctly from both S. torotoro and S. megarhyncha in underpart colouration and is mensurally—but not geographically—intermediate between them (but with more overlap with S. megarhyncha rather than its current conspecific). Vocally, both the long and short songs of S. t. ochracea are highly divergent from other Syma populations. This body of evidence suggests that S. t. ochracea merits species rank, for which I suggest the English name ‘Ochre-bellied Kingfisher’. The IUCN Red List status of the newly split S. ochracea is determined to be Near Threatened.