Diunatans is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of rorqual

Rorqual

Rorquals are the largest group of baleen whales, with nine species in two genera. They include the largest animal that has ever lived, the Blue Whale, which can reach , and another that easily reaches ; even the smallest of the group, the Northern Minke Whale, reaches .-Characteristics:Rorquals...

 whale

Whale

Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

. It lived in the North Sea

North Sea

In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

 during the Early Pliocene. Two specimens have been found from the Netherlands

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

. They were collected from the Kattendijk Formation in the province of Zeeland

Zeeland

Zeeland , also called Zealand in English, is the westernmost province of the Netherlands. The province, located in the south-west of the country, consists of a number of islands and a strip bordering Belgium. Its capital is Middelburg. With a population of about 380,000, its area is about...

, which is Zanclean

Zanclean

The Zanclean is the lowest stage or earliest age on the geologic time scale of the Pliocene. It spans the time between 5.332 and 3.6 Ma ± 0.005 Ma . It is preceded by the Messinian age of the Miocene epoch, and followed by the Piacenzian age....

 in age. Diunatans is considered to be a stem balaenopterid because it falls outside the Balaenoptera

Balaenoptera

Balaenoptera is a genus of Balaenopteridae, the Rorqual whales, and contains eight species. The species Balaenoptera omurai was published in 2003...

+Megaptera clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

, which includes all living rorqual whales. Its name means "long-distance swimmer", from the Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 diu meaning "long time" or "long distance", and natans, meaning "swimming." The type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 is D. luctoretemergo, named after the motto of Zeeland, "Luctor et Emergo" (Latin for "I struggle and I emerge").

Diunatans was around the size of the living minke whale

Common Minke Whale

The common minke whale or northern minke whale, , is a species of minke whale within the suborder of baleen whales.-Taxonomy:...

. Several distinguishing characteristics can be seen in the skull of Diunatans, including a large occipital condyle

Occipital condyle

The occipital condyles are undersurface facets of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra....

 and very small nasal bone

Nasal bone

The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, "the bridge" of the nose.Each has two surfaces and four borders....

s compared to other rorquals. The tympanic bulla, which encapsulates the middle ear

Middle ear

The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear has...

, is also large.

Diunatans is presently the only known fossil rorqual from the North Sea. Many other fossil rorquals have been described, but all are now considered nomena dubia. English paleontologist Richard Owen

Richard Owen

Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...

 named Balaenoptera definata, B. emarginata, and B. gibbosa in 1844. In the late 19th century, Belgian paleontologist Pierre-Joseph van Beneden

Pierre-Joseph van Beneden

Pierre-Joseph van Beneden was a Belgian zoologist and paleontologist.Born in Mechelen, Belgium, he studied medicine at the University of Louvain, and studied zoology in Paris under Georges Cuvier...

 named B. borealina, B. musculoides, B. rostratella, B. sibbaldina, Plesiocetus goropii, Megapteropsis robusta, and Megaptera affinus.