Multi-character taxonomic review, systematics, and biogeography of the Black-capped/Tawny-bellied Screech Owl (emMegascops/em ematricapilla/em-emM. watsonii/em) complex (Aves: Strigidae).

Megascops is the most species-rich owl genus in the New World, with 21 species currently recognized. Phylogenetic relationships within this genus are notoriously difficult to establish due to the considerable plumage similarity among species and polymorphism within species. Previous studies have suggested that the widespread lowland Amazonian M. watsonii might include more than one species, and that the Atlantic Forest endemic M. atricapilla is closely related to the M. watsonii complex, but these relationships are as yet poorly understood. A recently published phylogeny of Megascops demonstrated that M. watsonii is paraphyletic with respect to M. atricapilla and that genetic divergences among some populations of M. watsonii are equal to or surpass the degree of differentiation between some M. watsonii and M. atricapilla. To shed light on the taxonomic status of these species and populations within them, we conducted a multi-character study based on molecular, morphological, and vocal characters. We sequenced three mitochondrial (cytb, CO1 and ND2) and three nuclear genes (BF5, CHD and MUSK) for 49 specimens, covering most of the geographic ranges of M. watsonii and M. atricapilla, and used these sequences to estimate phylogenies under alternative Bayesian, Maximum Likelihood, and multilocus coalescent species tree approaches. We studied 252 specimens and vocal parameters from 83 recordings belonging to 65 individuals, distributed throughout the ranges of M. watsonii and M. atricapilla. We used Discriminant Function Analysis (DFA) to analyze both morphometric and vocal data, and a pairwise diagnostic test to evaluate the significance of vocal differences between distinct genetic lineages. Phylogenetic analyses consistently recovered six statistically well-supported clades whose relationships are not entirely in agreement with currently recognized species limits in M. watsonii and M. atricapilla. Morphometric analyses did not detect significant differences among clades. High plumage variation among individuals within clades was usually associated with the presence of two or more color morphs. By contrast, vocal analyses detected significant differentiation among some clades but considerable overlap among others, with some lineages (particularly the most widespread one) exhibiting significant regional variation. The combined results allow for a redefinition of species limits in both M. watsonii and M. atricapilla, with the recognition of four additional species, two of which we describe here as new. We estimated most cladogenesis in the Megascops atricapilla-M. watsonii complex as having taken place during the Plio-Pleistocene, with the development of the modern Amazonian and São Francisco drainages and the expansion and retraction of forest biomes during interglacial and glacial periods as likely events accounting for this relatively recent burst of diversification.

A new species of snook, Centropomus (Teleostei: Centropomidae), from northern South America, with notes on the geographic distribution of other species of the genus.

Centropomus irae sp. nov. (Centropomidae) is described from two localities in the state of Amapá, northern Brazil. The new species differs from all its congeners by the typically brown-colored lateral line, the relatively smaller mean interorbital width (4.1% of SL vs. 5.2-6.9%), mean snout length (8.9% of SL vs. 9.8-11.1%), mean diameter of the orbit (4.5% of SL vs. 5.4-7.3%), and mean mandible length (15.7% of SL vs.19.9-21.6%). The new species can also be distinguished from the similar Centropomus undecimalis by the number of scales around the caudal peduncle (18-23, usually 19-21, vs. 22-28, usually 24-27). With Centropomus irae sp. nov., seven species of the genus are now known to occur in the western Atlantic. The distribution of Centropomus in Brazilian waters is updated and a key to the species of this genus is presented. [Zoobank URL: urn:lsid:zoobank.org:act:3D497B38-48A5-4A6E-B377-6D57E82D4DE4[.

A dynamic continental moisture gradient drove Amazonian bird diversification.

The Amazon is the primary source of Neotropical diversity and a nexus for discussions on processes that drive biotic diversification. Biogeographers have focused on the roles of rivers and Pleistocene climate change in explaining high rates of speciation. We combine phylogeographic and niche-based paleodistributional projections for 23 upland terra firme forest bird lineages from across the Amazon to derive a new model of regional biological diversification. We found that climate-driven refugial dynamics interact with dynamic riverine barriers to produce a dominant pattern: Older lineages in the wetter western and northern parts of the Amazon gave rise to lineages in the drier southern and eastern parts. This climate/drainage basin evolution interaction links landscape dynamics with biotic diversification and explains the east-west diversity gradients across the Amazon.

Molecular data indicate the presence of a novel species of Centropomus (Centropomidae - Perciformes) in the Western Atlantic.

Centropomus undecimalis is distributed in the coastal waters of the western Atlantic between North Carolina and São Paulo, although very little is known of the genetic structure of its populations. Here, 148 C. undecimalis samples were obtained from six sites in the southwestern Atlantic, representing the Brazilian distribution of this species. Segments of three mitochondrial (Cytb, COI and 16S) and one nuclear (IGF1) gene were sequenced. The results of all analyses indicated the presence of a previously undetected lineage of Centropomus in the northern extreme of Brazil (Amapá) in the region of the Oiapoque estuary. This taxon is genetically distinct from all 12 recognized species of Centropomus. The populations from the Brazilian states of Pará, Maranhão, Ceará, Rio Grande do Norte, Rio de Janeiro and São Paulo were genetically similar to C. undecimalis from coastal areas of the Caribbean and USA. Nucleotide divergence between C. undecimalis and the new Oiapoque taxon are greater than or similar to those found between a number of valid Centropomus species. The estimated time of divergence between C. undecimalis and the new taxon is approximately 2 millionyears. The findings of the present study emphasize the need for a thorough taxonomic revision of this genus.