''Dasyomyliobatis'' is an extinct genus of prehistoric

stingray Stingrays are a group of sea Batoidea, rays, a type of cartilaginous fish. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (deepwate ...

in the

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 ...

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Dasyomyliobatidae, of the order

Myliobatiformes Myliobatiformes (), commonly known as stingrays, are one of the four orders of batoids, cartilaginous fishes related to sharks. They are members of the subclass elasmobranchs. They were formerly included in the order Rajiformes, but more recent ...

. It contains a single species, ''D. thomyorkei'', known from fossil remains from the

Early Eocene In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

-aged

Monte Bolca Monte Bolca is an Ypresian, Early Eocene-aged geologic site located near Verona, Italy, Verona, Italy. A ''Konservat-Lagerstätte'', it contains an extremely well-preserved and diverse marine biota, including the most diverse fish fauna of any Ce ...

Lagerstätte A Fossil-Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that preserves an exceptionally high amount of palaeontological information. ''Konzentrat-Lagerstätten'' preserv ...

of Italy. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

references the English musician and

Radiohead Radiohead are an English rock band formed in Abingdon-on-Thames, Abingdon, Oxfordshire, in 1985. The band members are Thom Yorke (vocals, guitar, piano, keyboards); brothers Jonny Greenwood (guitar, keyboards, other instruments) and Colin Gre ...

vocalist

Thom Yorke Thomas Edward Yorke (born 7 October 1968) is an English musician who is the vocalist and main songwriter of the rock band Radiohead. He plays guitar, bass, keyboards and other instruments, and is noted for his falsetto. ''Rolling Stone'' desc ...

. The genus is characterized by a unique hybrid

dentition Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...

and

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

morphology that allowed the shift from undulatory (undulating the ends of the fins in repeated waves) to

oscillatory Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...

(flapping the fins up and down) swimming. This change in locomotion and dentition likely led to a shift from a

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

lifestyle, and to exploit a variety of prey from soft-bodied to hard-shelled organisms. As suggested by the genus name, it displays intermediate traits between the whiptail stingrays ( Dasyatidae) and the eagle rays ( Myliobatidae), and can thus be considered a

transitional form A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross ...

in the origin of pelagic rays. Dasyomyliobatidae is thought to represent a

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to the Myliobatidae, and the two groups likely diverged during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

The Monte Bolca formation is thought to represent a shallow sea of the

Tethys Ocean The Tethys Ocean ( ; ), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean during much of the Mesozoic Era and early-mid Cenozoic Era. It was the predecessor to the modern Indian Ocean, the Mediterranean Sea, and the Eurasia ...

with scattered

coral reefs A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. ...

and seagrass beds. With its combination of traits, ''Dasyomyliobatis'' may have been able to forage in both these shallow-water ecosystems as well as the open ocean.

References

Myliobatiformes Eocene cartilaginous fish Monotypic prehistoric cartilaginous fish genera Fossil taxa described in 2023 Ypresian genera {{paleo-batoid-stub Radiohead Eocene fish of Europe Fossils of Italy