The Platyrhinidae are a

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 ...

of rays, commonly known as thornbacks due to their dorsal rows of large thorns. They resemble

guitarfish The guitarfish, also referred to as shovelnose rays, are a family, Rhinobatidae, of rays. The guitarfish are known for an elongated body with a flattened head and trunk and small, ray-like wings. The combined range of the various species is tro ...

es in shape. Though traditionally classified with

stingrays Stingrays are a group of sea 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 (deepwater stin ...

, molecular evidence suggests they are more closely related to electric rays in the order Torpediniformes. The earliest fossil member of this family is '' Tingitanius'' from 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 ...

(

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

) of the

Akrabou Formation The Akrabou Formation is a Late Cretaceous (latest Cenomanian to early/mid Turonian)-aged geological formation and Konservat-Lagerstätte in Morocco. It overlies the slightly older freshwater deposits of the Kem Kem Group, which it was once thought ...

in Morocco, known from a three-dimensionally preserved juvenile specimen. ''Tingitanius'' is thought to be the sister genus to '' Platyrhinoidis''.

Stem Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

-members of this family also known from fossil remains are '' Britobatos'' from the

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...

of Sahel Alma,

Lebanon Lebanon, officially the Republic of Lebanon, is a country in the Levant region of West Asia. Situated at the crossroads of the Mediterranean Basin and the Arabian Peninsula, it is bordered by Syria to the north and east, Israel to the south ...

, '' Tethybatis'' from the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

of Nardo, Italy, and '' Eoplatyrhina'' from the

Ypresian 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 ...

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 ...

, Italy.

Genera and species

* Genus '' Platyrhina'' J. P. Müller & Henle, 1838 ** '' Platyrhina hyugaensis'' Iwatsuki, Miyamoto & Nakaya, 2011 (Hyuga fanray) ** '' Platyrhina sinensis''

Bloch Bloch is a surname of German origin. Notable people with this surname include: A *Adele Bloch-Bauer (1881–1925), Austrian entrepreneur *Albert Bloch (1882–1961), American painter *Alexandre Bloch (1857–1919), French painter *Alfred Bloch ( ...

& J. G. Schneider, 1801 (fanray) ** '' Platyrhina tangi'' Iwatsuki, J. Zhang & Nakaya, 2011 (yellow-spotted fanray) * Genus '' Platyrhinoidis'' Garman 1881 ** '' Platyrhinoidis triseriata'' D. S. Jordan & Gilbert, 1880 (thornback guitarfish) The following fossil species are known:'''' *Genus †'' Britobatos'' Claeson, Underwood & Ward, 2013 **†''B. primarmatus'' ( Woodward, 1889) (=''

Raja Raja (; from , IAST ') is a noble or royal Sanskrit title historically used by some Indian subcontinent, Indian rulers and monarchs and highest-ranking nobles. The title was historically used in the Indian subcontinent and Southeast Asia. T ...

primarmata'' Woodward, 1889) *Genus †'' Eoplatyrhina'' Marramà, Carnevale, Claeson, Naylor & Kriwet, 2020 **†''E. bolcensis'' ( Heckel, 1851) (=''Platyrhina bolcensis'' Heckel, 1851) *Genus †'' Tingitanius'' Claeson, Underwood & Ward, 2013 **†''T. tenuimandibulus'' Claeson, Underwood & Ward, 2013 *Genus †'' Tethybatis'' de Carvalho, 2004 **†''T. selachoides'' de Carvalho, 2004

References

* Myliobatiformes Ray families Taxa named by David Starr Jordan {{rajiformes-stub Extant Turonian first appearances