And then there were two…

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Scientists have confirmed there are two species of slender-snouted crocodile in Africa. Although crocodiles have been around for millions of years, this is the first new species to be discovered in over 80 years. Georgina Lockwood tells us more…

The formation of the Cameroon Volcanic Line began over 80 million years ago, although the final uplift of the major peaks that would disrupt gene flow occurred in the mid to late Miocene, around 10–15 million years ago. The appearance of this mountain chain on the landscape had a profound impact on the slender-snouted crocodile population. The volcanic mountain chain created a physical divide, splitting the population into two isolated groups.

Until recently, scientists believed there was only one species of slender-snouted crocodile. The restricted gene flow resulted in two species – the West African slender-snouted crocodile (Mecistops cataphractus) and the newly confirmed Central African slender-snouted crocodile (Mecistops leptorhynchus). However, this is not good news for the West African species.

Based on amended population figures, the West African slender-snouted crocodile is now one of the rarest crocodile species in the world. In addition, the West African slender-snouted crocodile is drastically understudied. It is threatened by habitat loss, with large stretches of habitat being replaced by rubber, cocoa, and palm oil plantations.

A slender-snouted crocodile from Gabon. Photo: Donna Honey/See Wild Travels

Slender-snouted crocodiles are medium-sized (about three metres), with a characteristic elongated snout. The slender-snouted crocodile is one of seven different species of crocodile.

How to tell the slender-snouted crocodiles apart

The Central African slender-snouted crocodile can be found across the rainforests of Central Africa, with up to 70% of its population residing in Gabon. It has uncharacteristically smooth skin. Its head and skull tends to be narrower, with few facial markings that typically fade with age. Several populations of the Central African slender-snouted crocodile are known to contain a high proportion of very lightly coloured ‘blonde’ individuals. Its tongue is cream-coloured with no patterning.

The West African slender-snouted crocodile tends to be darker with a high degree of melanism (black individuals) in certain populations. It has a pronounced pattern along the jawline and dark splodges on its yellow tongue. Mecistops cataphractus has a more robust snout. Colouration and markings
vary highly in both species.

Both slender-snouted crocodile species are vocal and contribute significantly to the audioscape of the rainforest. The call of Mecistops cataphractus sounds like the engine of a lawnmower, while the call of the Central African species resembles a growling lion.

Although no in-depth studies have been done on the West African slender-snouted crocodiles, both species are believed to be predominantly piscivores. However, studies in Gabon reveal Mecistops leptorhynchus to be a generalist feeder, with crustaceans, insects, snakes, and even aquatic chevrotain forming part of its diet.

Both species of slender-snouted crocodile are mound-nesting. Mecistops leptorhynchus females are particularly shy nesters, building at the base of large trees hidden behind vegetative screens.

A slender-snouted crocodile from Gabon. Photo: Donna Honey/See Wild Travels

They both occupy a similar habitat and reside in rivers, lakes, swamps, flood forests, streams, and coastal lagoons. Certain populations have been found in slightly saline waters near San Pedro in Côte d’Ivoire, and in the N’gowe Lagoon and the Nyanga River in Gabon. Both species are able climbers and can be found basking on fallen trees above waterbodies.

A collaboration project between the government of Côte d’Ivoire, Matt Shirley, conservation scientist at the Tropical Conservation Institute of Florida International University, and various NGOs in the region, involves a captive breeding programme to restock wild populations of the West African species.

There are currently 34 breeding animals at Abidjan National Zoo in Côte d’Ivoire.

Information provided by Matt Shirley, conservation scientist at the Tropical Conservation Institute of Florida International University.

The facts

West African slender-snouted crocodile

Population: Estimated at no more than 500–1 000 individuals.
Status: Critically endangered.
Distribution: Senegal, Gambia, Guinea, Sierra Leone, Liberia, Côte d’Ivoire, Ghana, Nigeria. Its presence in Togo and Benin is unknown.
Threats: Habitat loss, bushmeat hunting, and bycatch in local, freshwater fisheries.
Latin name: Due to its thicker, rougher scales its Latin name, Mecistops cataphractus, translates to ‘suit of armour’.

Central African slender-snouted crocodile

Population: Estimated in the tens of thousands.
Status: Endangered.
Distribution: Cameroon, Equatorial Guinea, Gabon, Central African Republic, Republic of Congo, Democratic Republic of Congo, Tanzania, Zambia.
Threats: Bushmeat trade, deforestation, the illicit skin trade, and bycatch in local, freshwater fisheries.
Latin name: Mecistops leptorhynchus, meaning
‘long-beaked’.

Written by Georgina Lockwood 

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