Sveltonectes
Encyclopedia
Sveltonectes is an extinct genus
of ophthalmosaurid ichthyosaur
known from Ul’yanovsk region, western Russia
.
IRSNB
R269, an almost complete three-dimensionally preserved skeleton
which preserved partial skull
. It was collected in unnamed locality, in Ul’yanovsk, dating to the late Barremian
stage of the Early Cretaceous
, about 126 million years ago. Another thunnosaur described from the same locality, by Bogolubow (1909), is "Ichthyosaurus
" steleodon. It is a nomen dubium
that is twice the size and more robust than Sveltonectes.
Like some other ophthalmosaurids, Sveltonectes has a projection on the nasal bone
of the skull into the naris, a prefrontal forming part of the margin of the naris and a frontal forming part of the margin of the supratemporal fenestra. Sveltonectes is unique in that it has small, sharp teeth and numerous other peculiar features such as a very primitive prootic. The distinctive shape of these teeth suggest that it had a different feeding habit than other cretaceous ophthalmosaurids. Within Ophthalmosauridae, Sveltonectes is most closely related to Aegirosaurus
.
and the type species
is Sveltonectes insolitus. The generic name is derived from sveltos, Greek
for "agile", and nektes, Greek for "swimmer", and refers to its small size, streamlined skull and powerful girdle musculature. The specific name is derived from insolitus, Latin
for "unusual", in reference to the numerous unusual features of this ichthyosaur, as well as its unusual tooth morphology.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of ophthalmosaurid ichthyosaur
Ichthyosaur
Ichthyosaurs were giant marine reptiles that resembled fish and dolphins...
known from Ul’yanovsk region, western Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
.
Description
Sveltonectes is known from the holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
IRSNB
Royal Belgian Institute of Natural Sciences
The Royal Belgian Institute of Natural Sciences is a museum in the Belgian capital of Brussels dedicated to natural history. Its most important pieces are 30 fossilized Iguanodon skeletons, which were discovered in 1878 in Bernissart. The dinosaur hall of the museum is the world's largest museum...
R269, an almost complete three-dimensionally preserved skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
which preserved partial skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
. It was collected in unnamed locality, in Ul’yanovsk, dating to the late Barremian
Barremian
The Barremian is an age in the geologic timescale between 130.0 ± 1.5 Ma and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch...
stage of the Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
, about 126 million years ago. Another thunnosaur described from the same locality, by Bogolubow (1909), is "Ichthyosaurus
Ichthyosaurus
Ichthyosaurus is an extinct genus of ichthyosaur from the Early Jurassic of Europe . It is among the best known ichthyosaur genera, with the Order Ichthyosauria being named after it...
" steleodon. It is a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
that is twice the size and more robust than Sveltonectes.
Like some other ophthalmosaurids, Sveltonectes has a projection on the nasal bone
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 form, by their junction, "the bridge" of the nose.Each has two surfaces and four borders....
of the skull into the naris, a prefrontal forming part of the margin of the naris and a frontal forming part of the margin of the supratemporal fenestra. Sveltonectes is unique in that it has small, sharp teeth and numerous other peculiar features such as a very primitive prootic. The distinctive shape of these teeth suggest that it had a different feeding habit than other cretaceous ophthalmosaurids. Within Ophthalmosauridae, Sveltonectes is most closely related to Aegirosaurus
Aegirosaurus
Aegirosaurus is an extinct genus of ophthalmosaurid ichthyosaur known from the Late Jurassic and Early Cretaceous of Europe.-Discovery and species:...
.
Etymology
Sveltonectes was named by Valentin Fischer, Edwige Masure, Maxim S. Arkhangelsky and Pascal Godefroit in 20112011 in paleontology
-Lobopods:-Arachnids:-Insects:-Newly named jawless vertebrates:-Newly named acanthodian:-Newly named cartilaginous fishes:-Newly named bony fishes:-Newly named lepospondyls:-Newly named temnospondyls:-Newly named lissamphibians:...
and the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Sveltonectes insolitus. The generic name is derived from sveltos, Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
for "agile", and nektes, Greek for "swimmer", and refers to its small size, streamlined skull and powerful girdle musculature. The specific name is derived from insolitus, Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "unusual", in reference to the numerous unusual features of this ichthyosaur, as well as its unusual tooth morphology.