''Diunatans'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

rorqual Rorquals () are the largest group of baleen whales, which comprise the family Balaenopteridae, containing ten extant species in three genera. They include the largest animal that has ever lived, the blue whale, which can reach , and the fin wha ...

. It lived in the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

during the

Early Pliocene Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early ...

. Two specimens have been found from the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

. They were collected from the

Kattendijk Formation The Kattendijk Formation (also known as the Kattendijk Sands) is a five million years old marine geological formation north of Antwerp, Belgium. including the north-western parts of the Campine region. The area was named by De Heuter and Laga in 1 ...

in the province of

Zeeland , nl, Ik worstel en kom boven("I struggle and emerge") , anthem = "Zeeuws volkslied"("Zeelandic Anthem") , image_map = Zeeland in the Netherlands.svg , map_alt = , m ...

, which is

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 ± 0.005 Ma (million years ago) and 3.6 ± 0.005 Ma. It is preceded by the Messinian Age of the Miocene Epoch, and fol ...

in age. ''Diunatans'' is considered to be a

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

balaenopterid because it falls outside the ''

Balaenoptera ''Balaenoptera'' () is a genus of rorquals containing eight extant species. ''Balaenoptera'' comprises all but two of the extant species in its family (the humpback whale and gray whale); the genus is currently polyphyletic, with the two aforem ...

''+''

Megaptera The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hu ...

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

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

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

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

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

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 The minke whale (), or lesser rorqual, is a species complex of baleen whale. The two species of minke whale are the common (or northern) minke whale and the Antarctic (or southern) minke whale. The minke whale was first described by the Danish n ...

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

occipital condyle The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra. The condyles are oval or reniform (kidney-shaped) in shape, and their anteri ...

and very small

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 by their junction, form the bridge of the upper one third of the nose. Eac ...

s compared to other rorquals. The

tympanic bulla The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal. It originates as a separate bone (tympanic ...

, which encapsulates the

middle ear The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear). The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the ...

, is also large. ''Diunatans'' is the only known fossil rorqual from the North Sea. Many other fossil rorquals have been described, but all are now considered

nomina dubia In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

. English

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Owen is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Owe ...

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 FRS FRSE FGS FZS (19 December 1809 – 8 January 1894) was a Belgian zoologist and paleontologist. Life Born in Mechelen, Belgium, he studied medicine at the State University of Leuven, and studied zoology in Paris unde ...

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

References

Baleen whales Prehistoric cetacean genera Fossil taxa described in 2010 Pliocene cetaceans Fossils of the Netherlands {{paleo-whale-stub