Researchers from the Universidade Federal do Pará have conducted a thorough study on a bird species. Remarkably, what scientists previously believed to be a single bird species known as the silvery-cheeked antshrike (Sakesphoroides cristatus) is actually two distinct birds.
One of these newly identified species is called the northern silvery-cheeked antshrike (Sakesphoroides niedeguidonae). It is found exclusively in the Caatinga, a natural area located in northeastern Brazil’s interior region.
“The Caatinga is the largest patch of seasonal dry tropical forest in the Neotropics, located in northeastern Brazil and characterized mainly by deciduous vegetation and extreme rainfall seasonality,” explained Dr. Pablo Cerqueira from the Museu Paraense Emílio Goeldi at the Universidade Federal do Pará.
Historically, people saw the Caatinga as biologically poor, explained Dr. Cerqueira. However, recent studies have revealed new patterns of species diversification and discovered new species of frogs, mammals, insects, and fish.
The region’s geomorphology significantly shapes its biogeographic history, he continued. Altitudes range from sea level in the north to an average of 400 to 700 meters in Bahia and Minas Gerais and over 1,000 meters on the slopes of the Espinhaço range.
New species placed in genus Sakesphorus
Researchers noted that until recently, Sakesphoroides cristatus was classified under the genus Sakesphorus. However, new genetic and morphological data revealed it did not form a single evolutionary group (non-monophyletic), leading to its reclassification into the separate genus Sakesphoroides.
In their study, the team examined a total of 1,079 specimens of Sakesphoroides cristatus, including 818 males and 261 females. They also analyzed 115 different sound recordings to study variations in their songs.
Silvery-cheeked antshrike split into two species, including the newly named northern silvery-cheeked antshrike (Sakesphoroides niedeguidonae) pictured below: https://t.co/aIJWangA3s #birds #dinosaurs #PraiseToPasserines (📷Eduardo Brettas) pic.twitter.com/qxyqKvrzw5
— Alberta Claw (@albertonykus) June 18, 2024
Additionally, the researchers sequenced 58 tissue samples from various locations within the range of Sakesphoroides cristatus. Of these, 39 samples were from the left bank and 19 from the right bank of the São Francisco River.
Out of the 1,079 individuals (skins and photographs) examined, researchers found no distinct plumage differences among males. However, they identified two main plumage patterns among females, primarily across different sides of the river.
Females differ by distinct crown, back, and tail colors
Males of Sakesphoroides niedeguidonae have similar plumage to those of Sakesphoroides cristatus, the scientists explained. However, females of the two species differ in their crown, back, and tail colors.
Sakesphoroides niedeguidonae females are lighter in color with an amber color, while Sakesphoroides cristatus females have a chestnut color.
Additionally, the back of the Sakesphoroides niedeguidonae is olive brown compared to the cinnamon-brown back of Sakesphoroides cristatus.
The tail color of Sakesphoroides niedeguidonae is generally darker than that of Sakesphoroides cristatus, the researchers noted.
The most noticeable distinction is the presence of black and white barring in Sakesphoroides niedeguidonae, whereas Sakesphoroides cristatus displays more subdued brown and rufous bars, completely lacking white barring.