''Rhamphoichthys'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

billfish The billfish are a group (Xiphioidea) of saltwater fish, saltwater predatory fish characterised by prominent pointed beak, bills (rostrum (anatomy), rostra), and by their large size; some are longer than . Extant billfish include sailfish and m ...

-like plethodid

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

from

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 ...

(

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

). It contains one valid species, ''R. taxidiotis'' from the

Hesseltal Formation The Hesseltal Formation or Blackcoloured Formation is a Late Cretaceous (late Cenomanian to early Turonian) geological formation from northern Germany. It consists of lithified marls and limestone, with a unique series of black shales deposited ...

of Germany and the

Sannine Formation The Sannine Formation, also called the Sannine Limestone, is a Cretaceous geologic formation in Lebanon. It is a Konservat-Lagerstätte that contains a high diversity of well-preserved fish, reptiles, and invertebrates from the Tethys Ocean wit ...

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 ...

, in addition to two dubious species (''R. minor'' from England and ''R. stebbingi'' from England & Italy) that are considered ''nomina nuda'' due to their fragmentary nature. ''Rhamphoichthys'' was a large, streamlined tselfatiiform fish with an elongated

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

, akin to those of modern billfish and the co-occurring

pachycormid Pachycormiformes is an extinct order of marine Actinopterygii, ray-finned fish known from the Early Jurassic to the end of the Cretaceous. It only includes a single family, Pachycormidae. They were characterized by having serrated pectoral fins ( ...

fish ''

Protosphyraena ''Protosphyraena'' is a fossil genus of swordfish-like marine fish, that thrived worldwide during the Cretaceous period (Albian-Maastrichtian). Fossil remains of this taxon are mainly discovered in North America and Europe, and potential specime ...

''; the English and Italian species are only known from rostral fragments that were previously assigned to ''Protosphyraena''. It is one of the few longirostrine tselfatiiforms known, alongside the more fragmentary '' Martinichthys'' from

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. ''Rhamphoichthys'' rostra can be differentiated from those of ''Protosphyraena'' by being composed of paired bones as opposed to the single "rostrodermethmoid" bone that comprises pachycormid rostra. Much like billfishes, ''Protosphyraena'' had an upper jaw longer than the lower jaw and a high, long dorsal fin. However, unlike billfishes, it had a high pectoral fin and large scales on its body. ''Rhamphoichthys'' appears to have been a widespread and common

apex predator An apex predator, also known as a top predator or superpredator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the hig ...

in the Tethys and

Boreal Boreal, northern, of the north. Derived from the name of the god of the north wind from Ancient Greek civilisation, Boreas (god), Boreas. It may also refer to: Climatology and geography *Boreal (age), the first climatic phase of the Blytt-Sernand ...

seas. It likely had a very similar ecological role and feeding habits to modern billfishes.

References

{{Taxonbar, from=Q124299645 Tselfatiiformes Late Cretaceous fish of Asia Cretaceous fish of Europe Late Cretaceous bony fish Fossils of Lebanon Fossils of Germany Fossils of England Fossils of Italy Fossil taxa described in 2023 Prehistoric ray-finned fish genera