Red Knot - Taxonomy, Systematics and Evolution

Taxonomy, Systematics and Evolution

This Red Knot was first described by Linnaeus in the landmark 1758 tenth edition of his Systema Naturae as Tringa canutus. One theory is that it gets its name and species epithet from King Canute, Knot being another form of Canute; the name would refer to the knot's foraging along the tide line and the story of Canute and the tide. Another etymology is that the name is onomatopoeic, based on the bird's grunting call note.

The Red Knot and the Great Knot were originally the only two species placed in the genus Calidris but many other species of sandpiper were subsequently added. A 2004 study found that the genus was polyphyletic, and that the closest relative of the two knot species is the Surfbird (currently Aphriza virgata).

There are six subspecies, in order of size;

• C. c. roselaari Tomkovich, 1990 (largest)
• C. c. rufa (Wilson, 1813)
• C. c. canutus (Linnaeus, 1758)
• C. c. islandica (Linnaeus, 1767)
• C. c. rogersi (Mathews, 1913)
• C. c. piersmai Tomkovich, 2001 (smallest)

Studies based on mitochondrial sequence divergence and models of paleoclimatic changes during the glacial cycles suggest that canutus is the most basal population, separating about 20,000 years ago (95% confidence interval: 60,000–4,000 years ago) with two distinct lineages of the American and Siberian breeders emerging about 12,000 years ago (with a 95% confidence interval: 45,000–3,500 years ago).