Vallesaurus

Last updated

Vallesaurus
Temporal range: Late Triassic, Norian
Vallesaurus.jpg
Holotype specimen of Vallesaurus cenenis
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Drepanosauromorpha
Clade: Elyurosauria
Genus: Vallesaurus
Renesto & Binelli, 2006
Species
  • V. cenensisRenesto & Binelli, 2006 (type)
  • V. zorzinensisRenesto et al., 2010

Vallesaurus is an extinct genus of Late Triassic elyurosaur drepanosauromorph. First found in Northern Italy in 1975, it is one of the most primitive drepanosaurs. V. cenenis is the type species, which was first mentioned in 1991 but only formally described in 2006. [1] A second species, V. zorzinensis, was named in 2010. [2]

Contents

Discovery

The first specimen of Vallesaurus cenensis, MCSNB 4751, was found in 1975 by the staff of the Museo Civico di Scienze Naturali of Bergamo, Italy. The genus was named in respect of professor Valle, the former director of the museum. The species, on the other hand, was named after a local municipality called Cene, which was neighboring the site where the fossil was excavated. The specimen was given to palaeontologist Rupert Wild to study at the Staatliches Museum of Stuttgart, Germany. Wild briefly mentioned "Vallesaurus cenensis" in 1991, but without describing it formally or identifying the holotype specimen. Pinna (1993) listed the name when surveying Triassic reptiles in Italy, and identified MCSNB 4751 as its holotype. Renesto and Binelli formally described Vallesaurus cenensis in 2006, and attributed the name to Wild. [1] However, Renesto et al. (2010) later attributed the name to Renesto & Binelli (2006), arguing that Vallesaurus cenensis was a nomen nudum prior to that study. A second species, V. zorzinensis, was found in the same location and identified from the specimen MCSNB 4783. Its specific name referred to the Zorzino Limestone Formation, where the holotype was found. [2]

Description

Skeletal diagram of Vallesaurus. Scale bar = 1 cm Vallesaurus.png
Skeletal diagram of Vallesaurus. Scale bar = 1 cm

Vallesaurus is a small drepanosaurid about 15 centimetres (5.9 in) long. The manus (hand) is pentadactyl, with the 4th digit being the longest and equal in length to the humerus. The tarsus (ankle) has a centrale which articulates with the tibia. In addition, the foot of Vallesaurus also has modified distal tarsals and metatarsals, and a clawless hallux. [1]

Vallesaurus differs in some characteristics from another drepanosaur, Megalancosaurus . Vallesaurus has a proportionally shorter and higher snout, a thicker and larger maxilla and set of maxillary teeth, and a shorter cervical vertebra. It also lacks the fusion between the neural spines of the second and third dorsal vertebrae. Vallesaurus differs from Drepanosaurus , another drepanosaur, in that it lacks the enormous claw found on the second digit of the manus. It can be distinguished from Drepanosaurus, Megalancosaurus and possibly Dolabrosaurus in the lack of a terminal spine at the end of the tail. In addition, Vallesaurus also differs from Hypuronector , a related drepanosaur, in having anteroposteriorly extended neural spines of the anterior dorsal vertebrae and forelimbs much shorter than the hindlimbs. [1]

Related Research Articles

<i>Protoavis</i> Extinct genus of reptiles

Protoavis is a problematic taxon known from fragmentary remains from Late Triassic Norian stage deposits near Post, Texas. The animal's true classification has been the subject of much controversy, and there are many different interpretations of what the taxon actually is. When it was first described, the fossils were described as being from a primitive bird which, if the identification is valid, would push back avian origins some 60-75 million years.

<i>Dinocephalosaurus</i> Extinct genus of reptiles

Dinocephalosaurus is a genus of long necked, aquatic protorosaur that inhabited the Triassic seas of China. The genus contains the type and only known species, D. orientalis, which was named by Li in 2003. Unlike other long-necked protorosaurs, Dinocephalosaurus convergently evolved a long neck not through elongation of individual neck vertebrae, but through the addition of neck vertebrae that each had a moderate length. As indicated by phylogenetic analyses, it belonged in a separate lineage that also included at least its closest relative Pectodens, which was named the Dinocephalosauridae in 2021. Like tanystropheids, however, Dinocephalosaurus probably used its long neck to hunt, utilizing the fang-like teeth of its jaws to ensnare prey; proposals that it employed suction feeding have not been universally accepted. It was probably a marine animal by necessity, as suggested by the poorly-ossified and paddle-like limbs which would have prevented it from going ashore.

<i>Tanystropheus</i> Extinct genus of reptiles

Tanystropheus is an extinct genus of archosauromorph reptile which lived during the Triassic Period in Europe, Asia, and North America. It is recognisable by its extremely elongated neck, longer than the torso and tail combined. The neck was composed of 13 vertebrae strengthened by extensive cervical ribs. Tanystropheus is one of the most well-described non-archosauriform archosauromorphs, known from numerous fossils, including nearly complete skeletons. Some species within the genus may have reached a total length of 6 meters (20 ft), making Tanystropheus the longest non-archosauriform archosauromorph as well. Tanystropheus is the namesake of the family Tanystropheidae, a clade collecting many long-necked Triassic archosauromorphs previously described as "protorosaurs" or "prolacertiforms".

<span class="mw-page-title-main">Avicephala</span> Extinct clade of neodiapsid reptiles

Avicephala is a potentially polyphyletic grouping of extinct diapsid reptiles that lived during the Late Permian and Triassic periods characterised by superficially bird-like skulls and arboreal lifestyles. As a clade, Avicephala is defined as including the gliding weigeltisaurids and the arboreal drepanosaurs to the exclusion of other major diapsid groups. This relationship is not recovered in the majority of phylogenetic analyses of early diapsids and so Avicephala is typically regarded as an unnatural grouping. However, the clade was recovered again in 2021 in a redescription of Weigeltisaurus, raising the possibility that the clade may be valid after all.

<i>Askeptosaurus</i> Extinct genus of reptiles

Askeptosaurus is an extinct genus of askeptosauroid, a marine reptile from the extinct order Thalattosauria. Askeptosaurus is known from several well-preserved fossils found in Middle Triassic marine strata in what is now Italy and Switzerland.

<i>Megalancosaurus</i> Extinct genus of reptiles

Megalancosaurus is a genus of extinct reptile from the Late Triassic Dolomia di Forni Formation and Zorzino Limestone of northern Italy, and one of the best known drepanosaurids. The type species is M. preonensis; a translation of the animal's scientific name would be "long armed reptile from the Preone Valley."

<i>Hypuronector</i> Extinct genus of reptiles

Hypuronector is a genus of extinct drepanosaur reptile from the Late Triassic Lockatong Formation of New Jersey. The etymology of the name translates as "deep-tailed swimmer from the lake," in reference to its assumed aquatic habits hypothesized by its discoverers. Hypuronector was related to the arboreal Megalancosaurus. It was a small animal, estimated to be only 12 cm (4.7 in) long in life. So far dozens of specimens of Hypuronector are known, though scientists have not found any complete skeletons. This makes attempts to reconstruct Hypuronector's body or lifestyle highly speculative and controversial.

<i>Drepanosaurus</i> Extinct genus of reptiles

Drepanosaurus is a genus of arboreal (tree-dwelling) reptile that lived during the Triassic Period. It is a member of the Drepanosauridae, a group of diapsid reptiles known for their prehensile tails. Drepanosaurus was probably an insectivore, and lived in a coastal environment in what is now modern day Italy, as well as in a streamside environment in the midwestern United States.

<span class="mw-page-title-main">Drepanosaur</span> Extinct clade of reptiles

Drepanosaurs are a group of extinct reptiles that lived between the Carnian and Rhaetian stages of the late Triassic Period, approximately between 230 and 210 million years ago. The various species of drepanosaurid were characterized by specialized grasping limbs and often prehensile tails, adaptions for arboreal (tree-dwelling) and fossorial (digging) lifestyles, with some having also been suggested to be aquatic. Fossils of drepanosaurs have been found in Arizona, New Mexico, New Jersey, Utah, England, and northern Italy. The name is taken from the family's namesake genus Drepanosaurus, which means "sickle lizard," a reference to their strongly curved claws.

<i>Ctenosauriscus</i> Extinct genus of reptiles

Ctenosauriscus is an extinct genus of sail-backed poposauroid archosaur from Early Triassic deposits of Lower Saxony in northern Germany. It gives its name to the family Ctenosauriscidae, which includes other sail-backed poposauroids such as Arizonasaurus. Fossils have been found in latest Olenekian deposits around 247.5-247.2 million years old, making it one of the first known archosaurs.

<i>Macrocnemus</i> Extinct genus of reptiles

Macrocnemus is an extinct genus of archosauromorph reptile known from the Middle Triassic of Europe and China. Macrocnemus is a member of the Tanystropheidae family and includes three species. Macrocnemus bassanii, the first species to be named and described, is known from the Besano Formation and adjacent paleontological sites in the Italian and Swiss Alps. Macrocnemus fuyuanensis, on the other hand, is known from the Zhuganpo Formation in southern China. A third species, Macrocnemus obristi, is known from the Prosanto Formation of Switzerland and is characterized by gracile limbs. The name Macrocnemus is Greek for "long tibia".

Langobardisaurus is an extinct genus of tanystropheid archosauromorph reptile, with one known species, L. pandolfii. Its fossils have been found in Italy and Austria, and it lived during the Late Triassic period, roughly 228 to 201 million years ago. The Langobardisaurus was first discovered by Italian paleontologist Silvio Renesto in 1994 from the Calcare di Zorzino Formation in Northern Italy.

<i>Besanosaurus</i> Extinct genus of reptiles

Besanosaurus is a genus of large ichthyosaur that lived during the middle Triassic period, approximately 235 million years ago. This marine reptile came from its own family Besanosauridae and was named by Dal Sasso and Pinna in 1996. The type of species is Besanosaurus leptorhynchus meaning "long-beaked reptile from Besano."

The Forni Dolostone, also known as the Dolomia di Forni, is a Late Triassic dolomite geological formation in northeastern Italy. The formation was deposited in a lagoonal to shallow marine environment.

Hupehsuchia is an order of diapsid reptiles closely related to ichthyosaurs. The group was short-lasting, with a temporal range restricted to the late Olenekian age, spanning only a few million years of the Early Triassic. The order gets its name from Hubei Province, China, from which many specimens have been found. They are probable members of the clade Ichthyosauromorpha.

<i>Toretocnemus</i> Extinct genus of reptiles

Toretocnemus is an extinct genus of ichthyosaur. Its remains have been found in California, United States, in Triassic layers of the Carnian Hosselkus Limestone.

<i>Vancleavea</i> Extinct genus of reptiles

Vancleavea is a genus of extinct, armoured, non-archosaurian archosauriforms from the Late Triassic of western North America. The type and only known species is V. campi, named by Robert Long & Phillip A Murry in 1995. At that time, the genus was only known from fragmentary bones including osteoderms and vertebrae. However, since then many more fossils have been found, including a pair of nearly complete skeletons discovered in 2002. These finds have shown that members of the genus were bizarre semiaquatic reptiles. Vancleavea individuals had short snouts with large, fang-like teeth, and long bodies with small limbs. They were completely covered with bony plates known as osteoderms, which came in several different varieties distributed around the body. Phylogenetic analyses by professional paleontologists have shown that Vancleavea was an archosauriform, part of the lineage of reptiles that would lead to archosaurs such as dinosaurs and crocodilians. Vancleavea lacks certain traits which are present in most other archosauriforms, most notably the antorbital, mandibular and supratemporal fenestrae, which are weight-saving holes in the skulls of other taxa. However, other features clearly support its archosauriform identity, including a lack of intercentra, the presence of osteoderms, an ossified laterosphenoid, and several adaptations of the femur and ankle bones. In 2016, a new genus of archosauriform, Litorosuchus, was described. This genus resembled both Vancleavea and more typical archosauriforms in different respects, allowing Litorosuchus to act as a transitional fossil linking Vancleavea to less aberrant archosauriforms.

<span class="mw-page-title-main">Protorosauria</span> Extinct order of reptiles

Protorosauria is an extinct polyphyletic group of archosauromorph reptiles from the latest Middle Permian to the end of the Late Triassic of Asia, Europe and North America. It was named by the English anatomist and paleontologist Thomas Henry Huxley in 1871 as an order, originally to solely contain Protorosaurus. Other names which were once considered equivalent to Protorosauria include Prolacertiformes and Prolacertilia.

<i>Avicranium</i> Extinct genus of reptiles

Avicranium is a genus of extinct drepanosaur reptile known from the Chinle Formation of the late Triassic. The type species of Avicranium is Avicranium renestoi. "Avicranium" is Latin for "bird cranium", in reference to its unusual bird-like skull, while "renestoi" references Silvio Renesto, a paleontologist known for studies of Italian drepanosaurs.

<i>Vectiraptor</i> Dromaeosaurid dinosaur genus from Early Cretaceous England

Vectiraptor is a genus of dromaeosaurid dinosaur from the Barremian aged Wessex Formation of the United Kingdom. The type and only species is Vectiraptor greeni, known from associated dorsal vertebrae and a partial sacrum.

References

  1. 1 2 3 4 Renesto, Silvio; Binelli, Giorgio (31 March 2006). "Vallesaurus cenensis Wild, 1991, a drepanosaurid (Reptilia, Diapsida) from the Late Triassic of northern Italy". Rivista Italiana di Paleontologia e Stratigrafia. 112 (1): 77–94. doi:10.13130/2039-4942/5851.
  2. 1 2 Silvio Renesto; Justin A. Spielmann; Spencer G. Lucas & Giorgio Tarditi Spagnoli (2010). "The taxonomy and paleobiology of the Late Triassic (Carnian-Norian: Adamanian-Apachean) drepanosaurs (Diapsida: Archosauromorpha: Drepanosauromorpha)". New Mexico Museum of Natural History and Science Bulletin. 46: 1–81.