Tomas Diagne

African Chelonian Institute · Founder

Many species of terrestrial and freshwater chelonians are at risk of extinction, particularly rainforest species due to massive habitat loss. Therefore, the presence of peripheral and isolated populations can have considerable conservation value. This article confirms the presence of Pelusios gabonensis in an area of mature forest in western Côte d...

It is widely assumed that future climatic conditions, alongside their effect on local environments, will result in either a change in how species use their habitats or in a shift in species distributions. The Sahel region of Sub-Saharan Africa is expected to experience drastic changes in its average aridity and overall climate in the coming decades...

The Sahelian Flapshell Turtle, Cyclanorbis senegalensis (family Trionychidae) is the most widely distributed of the African members of the trionychid subfamily Cyclanorbinae, occurring across the sub-Saharan Sahel region from Senegal to Ethiopia. It is a moderate sized, sexually size-dimorphic freshwater turtle with females (curved carapace length...

Assessment of the species' status for Kinixys homeana. Previously considered as VU, this tortoise species is now reassessed as Critically Endangered (CR)

In April 2020, in the midst of a worldwide pandemic (COVID-19), our team was made aware of active sea turtle poaching near a major fishing port, Joal, in central Senegal. This discovery led to monthly surveys and a greater overall vigilance of the beaches and lagoons (where many of the turtles were being butchered and their carapaces stashed to cle...

The chelonian fauna of West Africa is relatively understudied and experiencing a multitude of threats. Moreover, the IUCN Red List status of several African species is both outdated and, we believe, underestimated. Herein, we cover projections for freshwater turtle and tortoise status trends in West Africa over the next decade. This geographic prio...

The African manatee (Trichechus senegalensis) is found in 21 countries, but very little is known about its movement patterns and habitat use. A unique opportunity to study the species occurred in January 2009, when five manatees were rescued from behind a new dam in a seasonal tributary of the Senegal River in eastern Senegal, and released back int...

Face-to-face interviews with local populations are often used to determine the distribution and population trends of elusive threatened species. Although interviewee responses may suffer from some bias, historical trends in the status of a species can be investigated from age-structured questionnaires. In this paper, we tested this idea by analysin...

Centrochelys sulcata, the African Spurred Tortoise (Family Testudinidae) is one of the largest terrestrial chelonians in the world, the largest extant continental tortoise, and the largest tortoise in Africa. Males are larger than females, and may exceed 100 kg in body mass, with a straight carapace length of up to 86.0 cm in males and 57.8 cm in f...

Turtles and tortoises (chelonians) have been integral components of global ecosystems for about 220 million years and have played important roles in human culture for at least 400,000 years. The chelonian shell is a remarkable evolutionary adaptation, facilitating success in terrestrial, freshwater and marine ecosystems. Today, more than half of th...

The Nubian Flapshell Turtle, Cyclanorbis elegans is one of the rarest turtle species in the world, and was even considered as possibly extinct since no free-ranging individuals has been recorded in the last years. Here, we report the record of two large adults (> 60 cm total carapace length) of this species along the White Nile river course, betwee...

We present a review and analysis of the conservation status and International Union for Conservation of Nature (IUCN) threat categories of all 360 currently recognized species of extant and recently extinct turtles and tortoises (Order Testudines). Our analysis is based on the 2018 IUCN Red List status of 251 listed species, augmented by provisiona...

No field studies have been conducted characterizing the habitat characteristics and eventual spatial resource partitioning between softshell turtles (family Trionychidae) in West and Central Africa. Here, we analyze the macrohabitat, microhabitat (along four variables), and apparent population abundance of Nile Soft-shelled Terrapin (Trionyx triung...

In this paper, the results of the first density investigations (via DISTANCE methodology on line transect surveys) for the threatened African spurred tortoise Centrochelys sulcata from West African Sahel (Niger and Burkina Faso) are reported. Spurred tortoises were encountered in 51.8% of Burkina Faso transects (n = 27) and in 60.7% of Niger transe...

Cycloderma aubryi inhabits a large range with little to moderate habitat degradation, but is exploited throughout its range for local consumption; this exploitation level is intensive enough to have led to documented declines at least locally, and possibly across much of its range. With an estimated generation time of 20 years, past declines and an...

The African Spurred Tortoise (Centrochelys sulcata), the second largest tortoise species in the world, is threatened with extinction because of a variety of threats, including habitat loss. Because details of habitat use for this species have not been published for wild populations of this species, we conducted this study to qualify and quantify ha...

The article presents the AMS (accelerator mass spectrometry) radiocarbon dating results of the baobab of Warang, Senegal. The investigation of the baobab revealed that it consists of 18 partially fused stems, which represents the largest number of stems reported for an African baobab. Three stems build the ring that closes a false cavity, while 15...

Red list assessment for the turtle species Trionyx triunguis

The African spurred tortoise (Centrochelys sulcata) is the second largest terrestrial turtle in the world, with a scattered distribution across the Sahel, in West Africa. This species is seriously threatened and declining consistently throughout the range, but little is kown on the causes of its decline. It has been hypothesized that this tortoise...

The African manatee is one of the least understood marine mammals in the world, and has been shown to be the least studied large mammal in Africa. Prior to this study, fewer than 20 genetic samples had been analyzed for the entire species, all of which came from five of 21 range countries and resulted in five control region and three cytochrome-b m...

The Nubian Flapshell Turtle, Cyclanorbis elegans (Family Trionychidae), is a large softshell turtle (total carapace length up to 700 mm) from north central Africa. It is the largest and least ossified member of the flapshell subfamily Cyclanorbinae. This highly aquatic species occurs in large rivers of the Sahelo-Sudanese belt from the Mole River i...

The Forest Hinge-back Tortoise, Kinixys erosa (Family Testudinidae), is a forest tortoise with considerable range over the continuous Guinea–Congo rainforest region in West and Central Africa. It is a medium-sized to large tortoise, with a carapace length reaching ca. 400 mm, and males larger than females. Tortoises of the genus Kinixys can close t...

Home’s Hinge-back tortoise, Kinixys homeana (Family Testudinidae), is a small to medium-sized forest tortoise (carapace length up to 220 mm), with a range extending over the coastal regions of the Gulf of Guinea, in the continuous Guinea-Congo West Africa rainforest region. The species belongs to a unique genus of tortoises that can close themselve...