No abstract

The characterization of species limits and diversification patterns across the geographically complex Indo-Pacific region has presented biogeographers and evolutionary biologists with great challenges. In the present study, we investigated the brown cuckoo dove (Macropygia amboinensis s.l.) species complex, whose distribution spans this entire region. We analyzed whether bioacoustic data are congruent with previous plumage-based classifications and whether glacial land bridges have impacted bioacoustic diversification in these doves. Using an unusually large vocal dataset of > 300 recordings from over 30 islands and 24 taxa, we analyzed 29 bioacoustic frequency and temporal parameters and tested for a correlation between geographical and bioacoustic distances. We found a weak correlation between geographical and bioacoustic distances. We identified numerous lineages that are bioacoustically distinct and proposed their elevation to the species level, leading to a doubling of the number of species in this complex and indicating a high proportion of cryptic species-level diversity that has previously gone unrecognized.

Background: The White-browed Shortwing (Brachypteryx montana) is widespread from the central Himalayas to the southeast Chinese mainland and the island of Taiwan, the Philippines and Indonesia. Multiple subspecies are recognised, and several of these have recently been suggested to be treated as separate species based on differences in morphology and songs. Methods: We here analyse plumage, morphometrics, songs, two mitochondrial and two nuclear markers, and geographical distributions of the two mainland Asian taxa B. m. cruralis and B. m. sinensis and the Taiwanese B. m. goodfellowi. Results: We conclude that these differ congruently in morphology, songs and DNA. Male B. m. goodfellowi is the most divergent in plumage (sexually monomorphic, unlike the two others; male similar to female), and B. m. cruralis and B. m. sinensis differ in male plumage maturation. The song of B. m. cruralis is strongly divergent from the others, whereas the songs of B. m. sinensis and B. m. goodfellowi are more similar to each other. Brachypteryx m. sinensis and B. m. goodfellowi are sisters, with an estimated divergence time 4.1 million years ago (mya; 95% highest posterior distribution [HPD] 2.8-5.5 mya), and B. m. cruralis separated from these two 5.8 mya (95% HPD 4.1-7.5 mya). We also report notable range extensions of B. m. sinensis as well as sympatry between this taxon and B. m. cruralis in Sichuan Province, China. Brachypteryx m. montana from Java is found to be more closely related to Lesser Shortwing (B. leucophris) and Rusty-bellied Shortwing (B. hyperythra) than to the mainland Asian and Taiwanese taxa. Conclusion: Our data support a recent proposal to treat the three mainland Asian and Taiwanese taxa as three species, separate from B. montana sensu stricto: B. cruralis (central Himalayas to south central China and south Vietnam), B. sinensis (north central to southeastern part of mainland China) and B. goodfellowi (Taiwan Island).

The common paradise-kingfisher, Tanysiptera galatea, species complex comprises 19 taxa distributed across New Guinea and Wallacea. Owing to its highly conserved morphological features, the lineage has been taxonomically confused, with 15 similar-plumaged taxa currently treated as conspecific. To shed light on species limits, we analysed eight bioacoustic parameters across 107 sound recordings using principal component analysis and the Isler criterion, among other methods. Our results show that multiple geographical entities of Tanysiptera paradise-kingfishers form discrete bioacoustic clusters across several vocal parameters, suggesting that species diversity of the common paradise-kingfisher complex has been greatly underestimated. Based on our results, we propose splitting T. galatea into six species: (1) Obi paradise-kingfisher, Tanysiptera obiensis; (2) Rossel paradise-kingfisher, Tanysiptera rosseliana; (3) Papuan paradise-kingfisher, T. galatea; (4) Halmahera paradise-kingfisher, Tanysiptera margarethae; (5) Morotai paradise-kingfisher, Tanysiptera doris; and (6) Amboyna paradise-kingfisher, Tanysiptera nais. Our work highlights that the non-invasive collection of avian vocal data is a crucial taxonomic tool and adds to increasing evidence that bioacoustic analyses are effective in elucidating cryptic diversity.

Background The Savanna Nightjar (Caprimulgus affinis) is a widespread, polytypic species which was previously treated as two or three species. It is currently treated as a single species based on superficial similarity of their songs but no detailed comparisons of the songs in this complex have been made. Methods A total of 15 acoustic variables were measured for the songs of 86 individuals representing 8 of the 10 subspecies in the complex. Results Three major groups can be distinguished based on univariate and multivariate analyses: a northern group consisting of the subspecies C. a. monticolus, C. a. amoyensis and C. a. stictomus; a southern group consisting of C. a. affinis, C. a. kasuidori, C. a. timorensis and C. a. propinquus; and a third group in the Philippines consisting of C. a. griseatus. Conclusions It is here argued that these groups are best treated as species, and that Franklin’s Nightjar (C. monticolus) and Kayumanggi Nightjar (C. griseatus) are reinstated as separate species.