For over 150 years, scientists believed that a massive, primeval crane species lived in Europe until the end of the last ice age. However, a new study led by Dr. John Stewart at Bournemouth University has overturned this long-held belief, revealing that the bones attributed to the extinct 'Grus primigenia' actually belong to the modern common crane (Grus grus).
From Morphology to Genetics
In the 19th century, French biologist Alphonse Milne-Edwards identified a 'giant' crane species based on bone fragments found in caves in southern France. Because these bones were dated to the end of the last ice age and were significantly larger than contemporary birds, they were classified as a distinct extinct species named Grus primigenia.
Previous research relied almost exclusively on the size and shape of these bones to categorize the birds. The new study, conducted in partnership with the Centre for Palaeogenetics in Stockholm, Sweden, moved beyond physical measurements by extracting and analyzing ancient DNA from 18 bones discovered in England, Wales, France, Germany, and the Balearic Islands.
“The use of DNA analysis has given us a more accurate picture of what they represent.”
— Study has solved a 150-year-old mystery into the identity of the extinct giant crane
The Role of Sexual Dimorphism
The genetic evidence revealed that these large bones were not from a separate species but were instead larger versions of the modern European common crane. Dr. Stewart noted that the confusion likely arose because cranes have large males and smaller females.
The study confirms that the bones previously thought to be a separate species actually belong to the modern common crane.
This sexual dimorphism may have led earlier researchers to believe they were looking at two different species—the living common crane and a larger, extinct relative—when they were actually looking at different sexes of the same bird.
Implications for Paleontology
This discovery highlights a significant risk in identifying extinct birds based solely on size differences. The researchers suggest that other bird species currently classified as extinct based on fossil size may also be misidentified, potentially leading to an overestimation of past extinction rates.
The team is now investigating why these cranes decreased in size over the last 20,000 years. While they suspect wetland drainage and human-driven land use changes are the primary causes, they emphasize that more work is required to confirm these specific environmental drivers.