''Togocetus'' ("Togo whale") is a genus of extinct

cetacea Cetacea (; , ) is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively c ...

n from the

Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it ...

(lower

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

) of

Togo Togo, officially the Togolese Republic, is a country in West Africa. It is bordered by Ghana to Ghana–Togo border, the west, Benin to Benin–Togo border, the east and Burkina Faso to Burkina Faso–Togo border, the north. It is one of the le ...

, known from a fossilized skeleton discovered a few kilometers north-east of

Lomé Lomé ( , ) is the Capital (political), capital and List of cities in Togo, largest city of Togo. It has an urban population of 837,437

Discovery and description

The skeleton was found in a

phosphate Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...

mining area, Kpogamé-Hahotoé, which is located just north of

Lake Togo Lake Togo ''(French language, French: Lac Togo)'' is the largest part of a lagoon in Togo, separated from the Atlantic Ocean by a narrow coastal strip. It is shallow and a popular location for water sports. Towns on the lake's shore include Agbod ...

. It was embedded in a phospharenite

bone bed A bone bed is any Geology, geological stratum or deposition (geology), deposit that contains bones of whatever kind. Inevitably, such deposits are Sedimentary rock, sedimentary in nature. Not a formal term, it tends to be used more to describe esp ...

dating back to 46 – 44 million years ago, and overlying an older rock unit, the

Tabligbo Tabligbo is a city and canton in Togo with 22,304 inhabitants (2010). It is the seat of Yoto prefecture in Maritime Region Maritime Region () is the southernmost of Togo Togo, officially the Togolese Republic, is a country in West Afric ...

Group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic iden ...

. The remains were described in 2014 by Philip D. Gingerich and

Henri Cappetta Henri Cappetta (August 29, 1946 – January 6, 2024) was a French ichthyologist specializing in the paleontology of sharks and rays. He was a managing director at the Institut des Sciences de l'Evolution in the University of Montpellier The Un ...

, who established for it the new

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus ''Togocetus'' and the new species ''T. traversei'', dedicated to Michel Traverse. According to the two authors, ''Togocetus'' was a semiaquatic animal which must have weighed around . It was a protocetid with rather primitive traits such as a still quite long neck, a

digitigrade In terrestrial vertebrates, digitigrade ( ) locomotion is walking or running on the toes (from the Latin ''digitus'', 'finger', and ''gradior'', 'walk'). A digitigrade animal is one that stands or walks with its toes (phalanges) on the ground, and ...

manus and a swim-specialized pes. It shared many similarities with the protocetid genera ''

Protocetus ''Protocetus atavus'' ("first whale") is an extinct species of primitive cetacean from Egypt. It lived during the middle Eocene period 45 million years ago. The first discovered protocetid, ''Protocetus atavus'' was described by based on a cran ...

'' and '' Pappocetus'', the main differences being a smaller

mandibular canal In human anatomy, the mandibular canal is a canal within the mandible that contains the inferior alveolar nerve, inferior alveolar artery, and inferior alveolar vein. It runs obliquely downward and forward in the ramus, and then horizontally ...

, the loss of the ''

fovea capitis femoris The femoral head (femur head or head of the femur) is the highest part of the thigh bone (femur). It is supported by the femoral neck. Structure The head is globular and forms rather more than a hemisphere, is directed upward, medialward, and a ...

'' (hence of the

ligament of head of femur The ligament of the head of the femur (round ligament of the femur, foveal ligament, or Fillmore's ligament) is a weak ligament located in the hip joint. It is triangular in shape and somewhat flattened. The ligament is implanted by its apex into ...

) and some traits related to the molar

trigonid The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth ...

s. Later analysis of ear structure evidence originally attributed to ''Togocetus'' raised some question regarding established understanding of protocetid evolution. The original analysis revealed a contradiction in assumed relationship between ear ossicle structure and mandibular canal size; later research and additional evidence revealed multiple places where more modern, specialized traits were blended unexpectedly with archaic ones, causing some controversy. Despite the fragmentary nature of the fossil record and the subtleties differentiating protocetids, ''T. traversei'' has consistently been shown to have unique features defining it, including a completely novel entoglenoid shape and several fossae otherwise not seen in contemporary cetaceans.

References

Bibliography

M Protocetidae Eocene mammals of Africa Monotypic prehistoric cetacean genera Fossil taxa described in 2014 Paleontology in Togo {{paleo-whale-stub