Leighton's Linsangs (Poiana leightoni): Ringtails of Ivory Coast, Liberia, and Sierra Leone

The world’s known animals typically answer to two kinds of names. The common name belongs within the experience of non-scientists and scientists. The scientific name -- which also is called the binomial (“two-name”), Latin or taxonomic name -- bespeaks the influence of scientific communities. In the case of Leighton’s linsang, for example, the common designation can be one of the following:

• Leighton’s linsang;
• Leighton’s oyan;
• West African linsang;
• West African oyan.

The less accurate designation linsang comes from the Javanese name for carnivorous, tree-dwelling mammals in Southeast Asia. But it continues to be used alongside the more accurate term oyan. Oyan is the localism encountered by Catholic missionary/Father G.L. Bates along Equatorial Guinea's Benito River in 1898.

The scientific community accepts as the current classificatory name for Leighton’s linsang Poiana leightoni. The origins of the genus name are shrouded most unscientifically in mystery. But a convincing explanation can be offered for the choice of name in 1864 by John Edward Gray (February 12, 1800 – March 7, 1875), as:

• Walsall-born British zoologist London-trained in medicine;
• Zoology keeper at London’s British Museum, 1840 – 1874;
• Zoology-related cataloguer and collector of insects, mammals, molluscs, and reptiles;
• Zoology-related publisher of 1,000+ papers, from 1821 onward.

Some specialists in the history of science connect the genus name with the location of a specimen’s first known-to-Europe discovery, on Fernando Pó (Bioko) Island off the south Atlantic coast of modern Equatorial Guinea.

The origins of the species name are not in doubt. Current identification continues the choice in 1908 by Reginald Innes Pocock (March 4, 1863 – August 9, 1947), as:

• Clifton-born British zoologist specializing in comparative anatomy, biology, and geology;
• Invertebrate specialist in charge of arachnid (“spider”), myriapod (“10,000 legs”), and ornithological (“bird”) collections at London’s Natural History Museum, 1886 – 1904;
• Superintendent of the London Zoo, 1904 – 1923.

It honors the British Museum-destined collection of Liberian Rubber Company businessman Leonard Leighton whose wife was the first white woman -- in 1908 -- to cross Liberia. Its description memorializes a forefeet-less, headless, skull-less specimen from 14.91 – 19.88 miles (24 – 32 kilometers) west of the:

• Cavalla and Duobe rivers;
• Putu Mountains.  

Sightings and specimens of Leighton’s linsang are rare. They cluster around:

• Guinea-Onakry, perhaps at the Kounounkan Massif;
• Ivory Coast at Gagnoa, Mont Sângbé National Park, and Nzi-Alakro;
• Liberia at Biple, Bongle, Deaple, Duotown, Igua, Siamonrovia, and Tappita as well as between Bao Town and Mali, between Bia and Zwedru, and perhaps within Sapo National Park;
• Sierra Leone, perhaps at the Gola Rainforest National Park.

The known location of specimens confirms the existence of Leighton’s linsang as part of the wildlife native to dense, even canopies in Upper Guinea’s moist-broadleaf, old-growth, and primary tropical rainforests. This Upper Guinean bio-geography of amazing faunal and floral diversity draws such natural enemies to Leighton’s linsang as predatory mammals, raptors, and reptiles.

Scientists attribute the paucity of sightings and specimens to the West African linsang’s:

• Sacredness, since coats are used in medicine bags of “exceptional properties and worth” (Rosevear, p. 224);
• Savviness, since collection is non-existent by museums and zoos;
• Scarcity, since territorial range is super-isolated from Richardson’s linsang (Poiana richardsonii) and super-restricted.

But predator-avoidance benefits from the habits and look of Leighton’s linsang. For example, Leighton’s linsang commit to:

• Building quickly and inhabiting briefly a series of leafy nests accommodating several bodies 6.56+ feet (2+ meters) above-ground;
• Consuming insects, kola-nuts, plant parts, and young birds;
• Delivering 2 newborns per yearly litter;
• Employing quick, quiet digitigrade (“on digits”) locomotion balanced by a tail which also serves as a blanket.

African linsangs appear similar. But Richardson’s linsang (Poiana richardsonii) claims:

• Black, small spots;
• Dull red-brown upper-sides;
• Off-white under-sides;
• 12 – 14 darkly “parallel-margined” Rosevear p. 228) tail rings.

Leighton’s linsang contrasts pristine-white under-parts with:

• Angularly-outlined, super-black, small spots;
• Brightly-buffed upper-parts;
• Darkly unbroken spinal line;
• 10 – 12 dark, “chevron-shaped” (Rosevear, p. 225) tail rings.

Bristle and super-soft hairs respectively grow to:

• 0.47 (12) and 0.39 inches (10 millimeters) and 0.52 – 0.59 (13 – 15) and 0.39 – 0.43 inches (10 – 11 millimeters) on the respective bodies and heads of Leighton’s and Richardson’s linsangs;
• 0.39 - 0.43 (10 – 11) and 0.28 – 0.35 inches (7 – 9 millimeters) on both linsangs’ tails.

Cylindrically-tapered guard-hairs grow 0.35 inches (15 millimeters) long on both linsangs’ tails.

Leighton’s linsang claims as defensive adaptations:

• Anal scent glands;
• 5 retractile-clawed digits per paw;
• The lower jaw’s 6 incisors, 1 canine, 8 premolars, and 4 molars;
• The upper jaw’s 6 incisors, 2 canines, 8 premolars, and 2 molars.

But fast fore-limbs and longer hind-limbs carry maximally-estimated:

• Head-and-body lengths: 11.81 – 14.96 inches (300 – 380 millimeters);
• Tail lengths: 13.78 – 15.75 inches (350 – 400 millimeters);
• Weights: 17.64 – 24.69 ounces (500 - 700 grams).

Self-defense may or may not suffice in sustaining Leighton’s linsangs in the interfaces between:

• Banana-, cocoa-, coffee-, livestock-, oil palm-, rice-, and sugarcane-oriented agro-industrialists;
• Bushmeat- and pelt-seeking villagers;
• Globally-warming climate change.

But protected areas, scientific research, and visitor support always weight sustainability in favor of endangered species.

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

opened green seed pods of Cola nitida; Serdang (now Seri Kembangan), Selangor, Malaysia: Michael Hermann/www.CropsfortheFuture.org, CC BY SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Fruits_of_Cola_nitida.JPG

John Edward Gray: 1855 albumen print portrait of John Edward Gray; photograph attributed to Maull & Polyblank: Public Domain Mark, via Wellcome Collection @ https://wellcomecollection.org/works/un2gxnr8

Distribution data from IUCN Red List: Chermundy/IUCN Red List of Threatened Species, species assessors and the authors of the spatial data, CC BY SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Leighton's_Linsang_area.png

William Peters, "Note on the Galago demidoffii of Fischer."
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taxidermied African Linsang (Poiana richardsonii) at the Natural History Museum in London: Emőke Dénes, CC BY SA 4.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:African_linsang_1.jpg

R.I. Pocock, Report upon a Small Collection of Mammalia brought from Liberia by Mr. Leonard Leighton."
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