According to a recent report released in the international journal of avian science Ibis, two previously "undescribed" warblers of the Cisticola genus known to have inhabited central Tanzania since the 1980s have been formally named by a dedicated group of researchers who went so far as to consult museum artifacts from 1961 to make their discovery.
"These putative new species have been illustrated in field guides on African birds, although with no formal name," the journal entry notes. "We use these [museum] specimens to provide formal descriptions of each form and, using DNA sequence data extracted from these specimens, we place them in a broad phylogenetic framework for the genus Cisticola."
A report from the outlet Sci-News explained the Cisticola genus is known for "small insect-eating birds" that have existed since the Old World. German naturalist Jakob Kaup originally recognized the "Cisticolidae" bird family in 1829, and since his ornithology work over 50 species of warblers have been recognized worldwide.
"Cisticola warblers primarily inhabit wetlands, savannah, broadleaved woodlands and upland habitats, almost exclusively in Africa," University of Copenhagen researcher Lars Dinesen and his international colleagues who assisted on the Ibis journal entry told Sci-News in a statement.
"Their identification and classification have been problematic for both professional and amateur ornithologists because of their cryptic coloration, seasonal variation in plumage and the patchy geographical distributions of many of the currently recognized species."
Indeed, Sci-News noted only two members of the Cisticola genus are found in populations outside of Africa: the Madagascan cisticola and the golden-headed warbler, which is found in Australia and several countries within Asia.
These particular species of warbler, called the Kilombero cisticola and the white-tailed cisticola, inhabit the floodplains in southwestern and central Tanzania, respectively.
"The presence of two undescribed Cisticola warblers in the marshes of the Kilombero floodplain in central Tanzania has been known since the 1980s and these putative new species have been illustrated in field guides on African birds, although with no formal name," Dinesen and his team told Sci-News. "Based on the combined evidence from genetics, morphology and bioacoustics, we conclude that these two cisticolas represent independent species."
Researchers concluded both bird families diverged somewhere between 2.5 and 3.5 million years ago, according to the Ibis report.
"We use our own and public recordings to characterize the vocal repertoire of each of these new species and compare song characteristics with other members of their respective clades," the report said. "Dating of nodes in the molecular phylogeny suggests that both cisticolas endemic to the Kilombero became isolated and diverged from their sister-species between 2.5 and 3.5 million years ago, long after the formation of the Eastern Arc Mountains and the Malawi Rift."
Dinesen and research team also used the scientific paper to implore to the larger animal conservation community to move both species to a critically endangered status, given environmental issues with the floodplain.
"The Kilombero floodplain was once connected with the vast wetland habitats of the ancient Zambian Luangwa drainage system," the team told Sci-News. "However, this connection was broken in the Late Miocene, with the formation of the Malawi Rift."
"We propose that both species should be classified as globally endangered, owing to immense anthropogenic pressures on the floodplain, as documented in several publications and by a recent Ramsar Advisory Mission," the paper noted.
This is not the only scientific bird news in recent weeks. A recently discovered extinct dwarf emu egg was found almost in its entirety, and has offered the global scientific community valuable information into the deceased species.