From Bird Guides
A nearly two-century-old taxonomic mystery has finally been resolved, with Southern Spectacled Owl - long considered a subspecies of Spectacled Owl - now recognised as a distinct species, according to a newly published review.
Spectacled Owl is a large, nocturnal forest raptor found from southern Mexico through much of tropical South America. For decades, ornithologists have debated the status of the pulsatrix subspecies, which differs in plumage and vocalsiations from other populations of the widespread species. Although originally described almost 200 years ago, conflicting interpretations of morphology and limited comparative data left its taxonomic position unresolved.
A recent study revisited this question, combining genetic analyses, detailed comparisons of plumage and measurements and an evaluation of vocalisations across the group’s range.
The results showed that pulsatrix differs significantly and consistently from other Spectacled Owl populations - enough to merit full species status under modern taxonomic criteria.
Under the revised treatment, Pulsatrix pulsatrix should now be considered a separate species. The taxon is native to south-eastern Brazil, from about Bahia south to Rio Grande do Sul in the area of Aparados da Serra National Park, and also bordering over into north-eastern Argentina.
The elevation of pulsatrix to full species status has implications for conservation and research. Species classification can influence how populations are monitored and prioritised, particularly in regions where habitat loss and fragmentation threaten forest-dependent birds. Clarifying species limits helps refine assessments of distribution, population size and trends - essential information for effective conservation planning. A recent study revisited this question, combining genetic analyses, detailed comparisons of plumage and measurements and an evaluation of vocalisations across the group’s range.
More info in comments. It’s all written in technical language, so I don’t want it to get overwhelming.
Abstract
The identification of valid species is central to biology, and genetic data have been essential in uncovering new taxonomic units across groups. For polytypic taxa, genetics helps distinguish valid units from natural variation. Pulsatrix perspicillata (Spectacled Owl) is a widespread polytypic species with six recognized subspecies. We used genetic data and museomics techniques to: (i) test the validity of Strix pulsatrix Wied, 1820 (=Pulsatrix perspicillata pulsatrix) as a species distinct from Pulsatrix perspicillata; and (ii) estimate the phylogenetic relationships and divergence times within the genus Pulsatrix Kaup, 1848. We conducted population structure and phylogenetic analyses using SNPs matrices and alignments of Ultraconserved Elements (UCEs) from 16 individuals of Pulsatrix spp., including four historical samples of P. p. pulsatrix.
Additionally, we sequenced the mtDNA-ND2 gene from 38 samples representing all known Pulsatrix species to further elucidate phylogenetic relationships and estimate divergence times. Our results indicate that Pulsatrix perspicillata pulsatrix represents an independent lineage from P. perspicillata, as supported by its reciprocal monophyly and distinct population structure. UCE analyses also grouped P. koeniswaldiana (Tawny-browed Owl) and P. melanota (Band-bellied Owl) into a distinct cluster. Phylogenetic analyses based on both UCEs and mtDNA-ND2 sequences support the monophyly of the genus Pulsatrix. Pulsatrix koeniswaldiana and P. melanota form a monophyletic group that is sister to P. perspicillata. Pulsatrix diverged in the Late Miocene and diversified in the Pliocene-Quaternary. The evolutionary history of Pulsatrix appears to have been influenced by (a) the final phase of the Andean uplift and (b) climatic oscillations during the Pleistocene. Pulsatrix p. pulsatrix shows genetic divergence consistent with a species-level split from P. perspicillata, and we henceforth recognize it as Pulsatrix pulsatrix (Wied, 1820). We recommend future studies to assess its current distribution and inform the development of conservation strategies.
Graphical Abstract
Introduction
The recognition, description, and delimitation of species are essential for better quantifying biodiversity and understanding the events and processes that have shaped it (Agapow et al., 2004, Peterson, 2006, Winker and Rasmussen, 2021). As a first step in quantifying biodiversity, systematic revisions allow researchers to identify and describe differences among organisms within a comparative framework. In recent years, significant advances in this topic for Neotropical groups have led to the description or validation of a wide range of species and genera (Cerqueira et al., 2024, Maas et al., 2023, Sangster et al., 2023). In addition, the use of genetic data to delimit independent evolutionary lineages has enhanced the scope and resolution of analyses for testing taxonomic hypotheses (Coates et al., 2018, Leaché et al., 2014, Pons et al., 2006). However, many questions remain regarding several poorly studied groups.
An example of this is the Spectacled Owl Pulsatrix perspicillata (Latham, 1790), a large nocturnal bird of prey found from southern Mexico to northern Argentina and southern Brazil. This owl primarily inhabits tropical and subtropical forests with mature trees, as well as savanna and gallery woodlands (König and Weick 2008). Six subspecies are currently recognized across its wide distribution: perspicillata, saturata, chapmani, trinitatis, boliviana, and pulsatrix (Holt et al., 2020c, Clements et al., 2024). The most controversial of these subspecies is P. perspicillata pulsatrix (Wied, 1820), originally described as Strix pulsatrix from a single male collected in 1816 along the lower Jequitinhonha River, southern Bahia, in Brazil. This taxon has a long and contentious history of taxonomic uncertainty, largely due to its rarity and distinctive morphological features. Since its description, it has been alternately treated as a valid species (e.g., Cory, 1918, Dubois, 1904, Kelso, 1934a, Kelso, 1934b, König and Weick, 2008, Schlegel, 1862, von Berlepsch, 1901), or as a subspecies of P. perspicillata (e.g., Peters, 1940, Pinto, 1938, Pinto, 1978, Clements et al., 2024, Dickinson, 2013, Gill and Donsker, 2025). Considerable divergence and uncertainty also exist regarding the geographic distribution of pulsatrix. Ihering (1904), Lillo (1909), Pinto, 1935, Pinto, 1938, and some later authors included Paraguay, northeastern Argentina, and some inland Brazilian states within this subspecies’ range, often without a critical examination of specimens (including the type; see Corrêa 2016 for a discussion). As a result, the distributional limits of P. p. pulsatrix have occasionally been questioned and reassessed over time (e.g., Wioneczak et al., 2022, Pinto and Camargo, 1961).
Compared to the nominate P. p. perspicillata, pulsatrix is larger and has a lighter brown coloration on the upperparts and chest band, with no noticeable difference in shade between the head and back. It also has shorter, creamy-buff eyebrows (rather than white) that do not extend conspicuously beyond the eyes, and the lower part of the facial disc is bordered by a narrow creamy-buff area extending from the throat to the lores. In addition, its tail and wing feathers are less distinctly banded and appear more uniformly colored (König and Weick 2008).
Primarily based on morphometric and plumage characters, Corrêa (2016) recently conducted a taxonomic revision of the genus Pulsatrix Kaup 1848, confirming the species-level status of P. perspicillata, P. melanota, and P. koeniswaldiana. Regarding P. perspicillata, she documented and described an extensive morphological variation across the six currently recognized subspecies throughout the species’ wide distribution. Given the significant geographic dispersion of the analyzed character states, which hindered a precise delimitation of these taxa, she proposed alternative hypotheses to explain this variation, such as polymorphism (see Fowlie and Krüger 2003). Nevertheless, several character states identified by Corrêa (2016) align with the description of P. perspicillata pulsatrix (Wied, 1820) and were exclusive to birds ranging from southern Bahia to Rio Grande do Sul in Brazil, except for a puzzling single specimen labeled as originating from ‘Peru’ (ANSP 2730). This specimen led the author to refrain from recognizing pulsatrix as a distinct taxon. However, until now, no genetic data have been available to support the hypothesis that P. p. pulsatrix is a distinct lineage from other taxa within P. perspicillata. Recently one specimen was collected from Ubatuba, São Paulo (Gonzaga and Peixoto 2024), but apart from that, all available material of this subspecies consists of a few old museum skins, collected up to 1974, and therefore lacking fresh tissue for DNA extraction (Corrêa, 2016). To address this issue, we applied a museomics protocol to retrieve and analyze genetic data from museum specimens of P. p. pulsatrix (Irestedt et al., 2022, Raxworthy and Smith, 2021). In museomics, historical DNA (hDNA) is extracted from specimens to sample geographic regions or taxa lacking fresh tissue, yielding short DNA fragments. This hDNA is often more fragmented, present in lower concentrations, and contains a smaller proportion of endogenous DNA. Nonetheless, hDNA has become widely used in taxonomic, conservation, biogeographical, and evolutionary studies across various taxonomic groups (Call et al., 2021, Ernst et al., 2022, Fabbri et al., 2025).
In this work, we used museomics techniques to determine whether Pulsatrix perspicillata pulsatrix is a genetically recognizable taxon. The answer to this question has important conservation implications, as P. p. pulsatrix is currently listed as Critically Endangered (CR) in the official list of Brazilian species threatened with extinction (MMA, 2022). We conducted this study under the framework of the Phylogenetic Species Concept (PSC), emphasizing the importance of diagnosability for delimiting independent taxa (following the PSC sensu Nixon and Wheeler, 1990), while also recognizing the necessity of monophyly among these diagnosable taxa (see Cracraft, 1985, Queiroz and Donoghue, 1988). We sequenced NGS markers (Ultraconserved Elements; Bejerano et al., 2004, Faircloth et al., 2012) to generate multiple alignments and SNP matrices for estimating the demographic structure and phylogenetic relationships of the Spectacled Owl Pulsatrix perspicillata (Latham, 1790). At the same time, we sequenced the mitochondrial gene ND2 to estimate the phylogenetic relationships and divergence times of P. koeniswaldiana, P. melanota, and P. perspicillata. Finally, we attempted to contextualize these mtDNA divergence times within biogeographical hypotheses proposed to explain the diversification of Neotropical avifauna, including geological events such as the uplift of the Andes and the formation of forest refugia during the Quaternary (Haffer, 2008, Cracraft et al., 2020). For instance, if diversification within the genus occurred during the Quaternary, we expected that the climatic oscillations of this period would have influenced the evolutionary trajectories of these lineages.
Section snippets
Sampling and DNA extraction
We obtained tissue samples from a total of 42 specimens, including 23 of Pulsatrix perspicillata, 5 of P. melanota, and 14 of P. koeniswaldiana (Fig. 1 and Table 1). The P. perspicillata samples include tissues extracted from the toepads of four museum specimens identified as P. p. pulsatrix (hereafter pulsatrix). One P. perspicillata blood sample was collected from an individual born in nature and later destined for captivity. The UCE (Ultraconserved Elements) sequence of P. melanota (KUNHM…
UCE sequences
We recovered an average of 3,496,693 reads per sample after trimming (N = 16; min = 25,542, max = 7,108,359). The assembly produced an average of 15,074 contigs per sample (total = 241,190, min = 910, max = 31,199), with an average length of 367.13 bp, for a total of 87,008,141 bp (Table S2). Due to the very low number of contigs recovered, we excluded two toepad samples (MZUSP 13966 and MCN 663) from the SNP datasets and one sample from the alignments (MZUSP 13966) (see Table S1)…
Discussion
In this study, we shed light on the validity of P. p. pulsatrix (Wied, 1820) as a distinct taxon separate from other populations of P. perspicillata (Latham, 1790) using genomic data, structure analyses, and phylogenetic methods. In addition, we presented the first phylogeny of the genus Pulsatrix (Strigiformes: Strigidae) using mitochondrial data. To date, no studies have been published on the genus with this level of sampling effort and amount of genetic data, incorporating both NGS and…
Taxonomic recommendations and future research
Based on our analyses, we propose the recognition of Pulsatrix pulsatrix (Wied, 1820) (type locality: Ilha da Chave, lower Belmonte River, now Jequitinhonha River, southern Bahia, Brazil; type specimen in the American Museum of Natural History – AMNH 6535) as a valid species separate from Pulsatrix perspicillata (Latham, 1790), as initially suggested by Berlepsch (1901), Dubois (1904), and later by Kelso, 1934a, Kelso, 1934b, Kelso, 1946 and König and Weick (2008). Fig. 5 illustrates the…
Conservation
Pulsatrix pulsatrix is an extremely rare species today, and given the scarcity of historical records, it is likely that it has always been scarce throughout its range. Of the 475 specimens of the genus Pulsatrix examined by Corrêa (2016), only a small number exhibited the morphological characteristics associated with this taxon. Prior to 2020, the species had been found in the wild only once since W. Belton collected the last known specimens in 1974 (Belton, 1984). In September and November…