''Rhamphocephalus'' ("beak head") 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 ...
of fossil reptile from the
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...
(
Bathonian
In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age.
Strat ...
stage)
Great Oolite Group
The Great Oolite Group is a Middle Jurassic stratigraphic unit that outcrops in southern England. It consists of a complex set of marine deposits primarily mudstone and bioclastic ooidal and fine grained limestone, deposited in nearshore to shel ...
of
Gloucestershire
Gloucestershire ( abbreviated Glos) is a county in South West England. The county comprises part of the Cotswold Hills, part of the flat fertile valley of the River Severn and the entire Forest of Dean.
The county town is the city of Gl ...
, England. The name was erected as a genus of
pterosaur
Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 to ...
and became a '
wastebasket taxon
Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined ...
' for British Jurassic pterosaur remains until a recent revision.
''Rhamphocephalus'' comprises several named species, two of which are pterosaurian, but the type species - ''R. prestwichi'' - is based on remains now identified as a
thalattosuchia
Thalattosuchia is a clade of marine crocodylomorphs from the Early Jurassic to the Early Cretaceous that had a cosmopolitan distribution. They are colloquially referred to as marine crocodiles or sea crocodiles, though they are not members of Cro ...
n. Because it is poorly preserved and lacks features that distinguish it from other thalattosuchians, ''R. prestwichi'' is considered an invalid species and the genus ''Rhamphocephalus'' is a
nomen dubium
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 ...
.
Reassessments of other ''Rhamphocephalus'' species suggest they are also undiagnostic to species level, although they have properties allowing referral to some Jurassic pterosaur groups.
Taxonomy
The type species, ''R. prestwichi'', is known from the skull roof fragment OUM J.28266, found the Kineton Thorns Quarry, Stow-On-Wold, Gloucestershire. Seeley (1880) noted that the cranial bones of ''Rhamphocephalus'' are arranged more like that of a crocodyliform rather than a pterosaur.
[Seeley H.G. 1880. On ''Rhamphocephalus prestwichi'' Seeley, an Ornithosaurian from the Stonesfield Slate of Kineton. Quart. J. Geol. Soc. 36: 27-30] Although assigned to Pterosauria by previous authors, in their review of pterosaur remains from the Great Oolite group, O'Sullivan and Martill (2018) demonstrated that ''Rhamphocephalus'' belongs to Thalattosuchia rather than Pterosauria due to differences with pterosaurs in the cranial bone arrangement. They also argued that the specimen lacked good autapomorphoes and the genus was a nomen dubium.
[Michael O’Sullivan; David M. Martill (2018). "Pterosauria of the Great Oolite Group (Bathonian, Middle Jurassic) of Oxfordshire and Gloucestershire, England". Acta Palaeontologica Polonica. Online edition. doi:10.4202/app.00490.2018.]
Misassigned species
''Pterodactylus bucklandii'' von Meyer, 1832 and ''Rhamphorhynchus depressirostris'' Huxley, 1859, both based on jaw material, were previously assigned to ''Rhamphocephalus'', along with the nominal species ''Pterodactylus aclandi'', ''P. duncani'', and ''P. kiddi'', which are based on phalangeal remains. However, the thalattosuchian reclassification of ''Rhamphocephalus'' rendered this referral untenable, although ''bucklandii'' and ''depressirostris'' were clearly pterosaurian, and ''P. bucklandii'' was assigned to Rhamphorhychinae indeterminate, while ''Rhamphorhynchus depressirostris'' was assigned to ?Scaphognathinae indeterminate.
[ Andres (2021) resurrects the genus name '']Dolicorhamphus
''Dolicorhamphus'' is an extinct genus of pterosaurs from the Middle Jurassic Taynton Limestone Formation and Fuller's Earth Formations of England. The genus contains two species, ''D. bucklandii'' and ''D. depressirostris''.
Both species of ''D ...
'' Seeley 1875 for ''depressirostris'' and ''bucklandii'', finding both to belong to a monophyletic genus of pterosaurs closely related to ''Klobiodon
''Klobiodon'' is a genus of rhamphorhynchid pterosaur from the Middle Jurassic Taynton Limestone Formation of Oxfordshire, England.
Etymology
The type species of ''Klobiodon'' is ''Klobiodon rochei''. The generic name ''Klobiodon'' means "small ...
''.
See also
References
''Rhamphocephalus''
in the Paleobiology Database.
Middle Jurassic reptiles of Europe
Taxa named by Harry Seeley
Fossil taxa described in 1880
Bathonian life
Prehistoric pseudosuchian genera
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