Vulcanodon (meaning "volcano tooth") is an extinct genus of sauropod dinosaur from the Early Jurassic of southern Africa. The only known species is V. karibaensis. Discovered in 1969 in Rhodesia (now known as Zimbabwe), it was regarded as the earliest known sauropod for decades, and is still one of the most primitive sauropods that has been discovered. As a quadrupedal, ground-dwelling herbivore, Vulcanodon already showed the typical sauropod body plan with column-like legs and a long neck and tail. It was smaller than most other sauropods, measuring approximately eleven metres (35 ft) in length. Vulcanodon is known from a fragmentary skeleton including much of the pelvic girdle, hindlimbs, forearms, and tail, but lacking the trunk and neck vertebrae as well as the skull.
Originally, this genus was believed to be a prosauropod because of the knife-shaped teeth found near its fossils, which fit in with the idea that prosauropods were omnivorous. Scientists now know that the teeth belonged to an unidentified theropod that may have scavenged on the Vulcanodon carcass. Vulcanodon is now known to be a true sauropod. Upon the discovery of the related Tazoudasaurus, both animals were unified in the family Vulcanodontidae, though this has not been universally accepted.
|Plastic model of a herd in the JuraPark in Solec Kujawski, Poland|
Vulcanodon was a small sauropod. In 2010, Gregory S. Paul estimated its length at eleven metres, its weight at 3.5 tonnes. Some books mention lower estimates of approximately 6.5 m (21 ft). The thighbone was 110 centimeters long.
As one of the earliest and basalmost sauropods, it is important for understanding the early evolution of this group. Sauropods descend from basal sauropodomorphs (informally called "prosauropods"), which were primitively bipedal (two-legged). While Vulcanodon already was fully quadrupedal (four-legged), its limb proportions were intermediate between those of its prosauropod ancestors and those of later, more derived sauropods. Its forelimbs were much more similar to later sauropods than basal sauropodomorphs because they are straight, much more gracile, and the proximal end of the ulna is v-shaped. Unfortunately, no skull or neck of Vulcanodon is known, although it is otherwise very well-known.
Vulcanodon's limbs were sturdy and column-like, and its forelimbs were already proportionally long, reaching 76% of hindlimb length. Its lower leg, metatarsus, and toes were shortened in comparison to its bipedal ancestors, but still not as short as in later sauropods. The sacrum was made out of four fused sacral vertebrae; "prosauropods" possessed only three sacrals. The tail vertebra bodies already showed an incipient excavation of their lateral sides, saving weight and giving them a waisted appearance when viewed from below. In later sauropods, this excavations were enlarged to form extensive perforated pockets called pleurocoels. Contrasting the many sauropod-like features of the skeleton, the pelvis was relatively primitive, reminiscent of its "prosauropod" ancestors. One such feature is that the brevis shelf of the ilium has a fossa, which is not found in any more derived sauropods.
The hallux (the first toe of the foot) showed a large claw that was flattened laterally, as seen in "prosauropods". However, the claws of the second and third toe were unusual in being nail-like and broader than deep. This feature was also found in the probably closely related Tazoudasaurus, but is absent in all other sauropods. The feet of Vulcanodon were semiplantigrade as in later sauropods (where both the digits and part of the metatarsals contact the ground), a derived feature not found in more basal sauropods like Isanosaurus. However, they also retained primitive features, like the fact that the phalanges were not reduced.
Many of the features found in sauropods that basal sauropodomorphs lack are related to the change in body size. The greatest regions affected by this are the hind limbs and pelvis. For example, an elongating of the ilium, size reduction of the lesser trochanter shelf, and semiplantigrade posture are some features that indicate the amount and positioning of leg muscles being modified. Vulcanodon possessed these features, the latter of which is seen earliest in it. However, Vulcanodon does not have reduced distal phalanges, which are seen in Shunosaurus and all more derived sauropods. This means that while the muscle positioning of its legs were changing, they had not yet reduced in the distal region of the limb.
Vulcanodon is known only from a single locality on an island in Lake Kariba, the largest artificial lake in the world, in northern Zimbabwe (formerly Rhodesia). The island, located west of Bumi Hills, is called "Island 126/127", after early, unpublished lake charts, but has no formal name. The first bone was found by B. A. Gibson of the town of Kariba in July 1969, and an excavation team collected the specimen in October 1969, March 1970 and May 1970. In the later half of 1970, the new find was presented at a scientific symposium in Cape Town and a brief note was published. The find was formally named and described in July 1972 by palaeontologist Michael Raath. The name Vulcanodon (lat. Vulcanus – Roman god of fire; gr. odon – "tooth") points to the fact that the skeleton was found in sandstone, that was at the time misinterpreted to be part of the Batoka Formation but is actually part of the Forest Sandstone lays a few metres below the lava flows of the Batoka Formation, and emphasizes the peculiar knife-shaped teeth that are now known to belong to a theropod. The specific name, karibaensis, refers to the place of discovery on a small island in Lake Kariba. It was one of the first dinosaurs found in Zimbabwe.
The skeleton (catalogue number QG24) has been found weathering out of a hill slope and was partially eroded by surface exponation and plant roots. It includes the pelvis and sacrum, most of the left hind limb and foot, a right thigh bone, and twelve anterior tail vertebrae. These remains pertain to a single individual as they were all found articulated (still connected together). Additionally, several disarticulated bones were found, including the right forearm and some metacarpalia and phalanges from both the right and left forefeet, probably also pertaining to this individual. Later, the site was revisited by the scientists Geoffrey Bond and Michael Cooper, who were able to collect additional remains including a scapula (specimen QG152, a shoulder blade) and a fragment of a neck vertebra. These remains show that more than one individual was present, and it is possible that they do not pertain to Vulcanodon at all. Today, the Vulcanodon remains are stored in the Natural History Museum of Zimbabwe in Bulawayo.
Raath (1972) noted the discovery of nine fragmentary carnivorous teeth near the pelvic region of the skeleton. He argued that the Vulcanodon carcass might have been embedded with the head and neck bended backwards above the pelvis, a posture called death pose that is frequently seen in dinosaur skeletons. The teeth would have been the only preserved elements of the skull. However, as shown by Cooper (1984), these teeth do not pertain to Vulcanodon but to a theropod dinosaur that may have scavenged on the Vulcanodon carcass.
Originally, Michael Raath (1972) described Vulcanodon not as a sauropod but as an advanced, specialized prosauropod, possibly of the family Melanorosauridae. According to Raath, the sauropod-like limb proportions in Vulcanodon evolved independently from those of true sauropods (through convergent evolution). He argued that primitive features of the pelvis as well as the knife-shaped teeth preclude a classification within the Sauropoda. The teeth, however, are now known to belong to a theropod. Arthur Cruickshank (1975) was the first to show that Vulcanodon was indeed a sauropod, arguing that the fifth metatarsal bone was equally long as the remaining metatarsals, a condition seen in other sauropods but not in prosauropods. Today, Vulcanodon is universally accepted to be one of the most basal (primitive) members of Sauropoda.
Michael Cooper (1984) erected a new family, the Vulcanodontidae, which he regarded as the "rootstock" for later sauropod families. Originally, the Vulcanodontidae included Vulcanodon and the Indian Barapasaurus, but subsequent studies attributed a number of other, much more fragmentary early sauropod genera to this family, including Ohmdenosaurus and Zizhongosaurus. Paul Upchurch (1995) showed that Barapasaurus was more closely related to later, more advanced sauropods than to Vulcanodon, rendering the Vulcanodontidae polyphyletic and therefore invalid.
The exact relationships with other basal sauropod genera remain unclear. Ronan Allain and colleagues (2004, 2008) found that Vulcanodon is most closely related to Tazoudasaurus, a newly discovered sauropod genus from Morocco. These researchers suggested reintroducing the name Vulcanodontidae to name the clade containing Vulcanodon and Tazoudasaurus. However, this sibling relationship between Tazoudasaurus and Vulcanodon could not be confirmed by other analyses.
Adam Yates (2004) described a single sauropod tail vertebra from the Upper Elliot Formation of South Africa that may belong to a genus closely related to Vulcanodon. The Upper Elliot Formation is famous for its abundant fossils of the prosauropod Massospondylus.
During the later part of the Lower Jurassic, southern Africa was the scene of massive volcanism, resulting in extensive lava flows (so called flood basalts) that covered much of southern Africa and Antarctica. These basalt formations are known as the Karoo-Ferrar large igneous province. Vulcanodon comes from the "Vulcanodon beds", a fossil-bearing sediment unit within the Batoka Formation, which is composed primarily of flood basalts. The skeleton was found near the top of a 30 m (98.5 ft) thick bedded layer of sand- and siltstone that is over- and underlain by flood basalts.
It was long assumed that Vulcanodon lived during the lowermost (earliest) part of the Jurassic (the Hettangian stage) or at the Triassic-Jurassic boundary, approximately 200 million years ago. Therefore, it was regarded as the earliest sauropod known, until the discovery of the even older Late Triassic Isanosaurus was announced in 2000. Adam Yates (2004) has recently shown that Vulcanodon is actually much younger than previously thought, dating to the uppermost (latest) part of the Lower Jurassic during the Toarcian stage, approximately 175–183 million years ago. – thus, it is contemporary to the closely related Tazoudasaurus. Although the locality of Vulcanodon itself cannot be dated radiometrically because of weathering of the lavas, it would roughly be a contemporary to Karoo lavas from other localities, as the entire sequence of volcanic eruptions was finished within one million years.
Vulcanodon is the only named dinosaur from the Vulcanodon beds. Cooper (1984) noted that the habitat was desert-like, as indicated by aeolian (wind-blown) sands of the Forest Sandstone Formation, which underlies the "Vulcanodon beds". The sediments in which Vulcanodon was found may represent distal alluvial fan deposits which levelled off into a desert landscape, which may have contained lakes during the wet season. The individual may have roamed the shores of wadis that cut into the alluvial fan deposits, unless the carcass was transported to the locality it was found by flooding.
Initially, sauropods were thought to be mainly aquatic, inhabiting lush peat swamps and being captive to the buoyancy of water to support their giant body weights. In 1984, Cooper pointed out that Vulcanodon, the most primitive sauropod known at that time, lived in a desert like environment and therefore must have been terrestrial. This indicated that the large body size of sauropods, as already seen in Vulcanodon, had not evolved as an adaptation to an aquatic life style.
Aardonyx (Afrikaans aard, "earth" + Greek onux, "nail, claw") is a genus of basal sauropodomorph dinosaur. It is known from the type species Aardonyx celestae found from the Lower Jurassic Elliot Formation of South Africa. A. celestae was named after Celeste Yates, who prepared much of the first known fossil material of the species. It has arm features that are intermediate between prosauropods and sauropods.Based on the structure of the hind limbs and pelvic girdle of Aardonyx, the dinosaur normally moved bipedally but could drop to quadrupedal movement similar to Iguanodon. It shares some attributes with giant quadrupedal sauropods like Apatosaurus. Australian paleontologist Adam Yates and his team's discovery of the genus was published online before print in Proceedings of the Royal Society B in November 2009, and was scheduled to appear in the March 2010 issue. British paleontologist Paul Barrett of the Natural History Museum, London, who was not involved in the research, commented that the discovery of Aardonyx "helps to fill a marked gap in our knowledge of sauropod evolution, showing how a primarily two-legged animal could start to acquire the specific features necessary for a life spent on all-fours".According to Dr. Matthew Bonnan, a co-author on the study, "We already knew that the earliest sauropods and near-sauropods would be bipeds. What Aardonyx shows us, however, is that walking quadrupedally and bearing weight on the inside of the foot is a trend that started very early in these dinosaurs, much earlier than previously hypothesized." Bonnan adds, "On a scientific level, it's really fulfilling to have a hypothesis on how you think dinosaurs got large, then to test that in the field and get back these kind of data — a new dinosaur — that really does start to fill in some of those anatomical gaps."Barapasaurus
Barapasaurus ( bə-RAH-pə-SAWR-əs) is a genus of basal sauropod dinosaur from Early Jurassic rocks of India. The only species is B. tagorei. Barapasaurus comes from the lower part of the Kota Formation, that dates back to the Sinemurian and Pliensbachian stages of the early Jurassic. It is therefore one of the earliest known sauropods. Barapasaurus is known from approximately 300 bones from at least six individuals, so that the skeleton is almost completely known except for the anterior cervical vertebrae and the skull. This makes Barapasaurus one of the most completely known sauropods from the early Jurassic.Batoka Formation
The Batoka Formation is a geological formation in the Zambezi valley in Botswana, Zambia and Zimbabwe. It is predominantly a volcanic unit comprising mainly basalts. It was formerly thought to contain sand stones containing the dinosaur Vulcanodon, however this was shown to be in error resulting from interpreting folding of the rocks as separate layers, with the sandstone layers actually being from the underlying Forest Sandstone.Cetiosauridae
Cetiosauridae is a family of sauropod dinosaurs. While traditionally a wastebasket taxon containing various unrelated species, some recent studies have found that it may represent a natural clade. Additionally, at least one study has suggested that the mamenchisaurids may represent a sub-group of the cetiosaurids, which would be termed Mamenchisaurinae.Chinshakiangosaurus
Chinshakiangosaurus (JIN-shah-jiahng-uh-SOR-us, meaning "Chinshakiang lizard") is a genus of dinosaur and probably one of the most basal sauropods known. The only species, Chinshakiangosaurus chunghoensis, is known from a fragmentary skeleton found in Lower Jurassic rocks in China. Chinshakiangosaurus is one of the few basal sauropods with preserved skull bones and therefore important for the understanding of the early evolution of this group. It shows that early sauropods may have possessed fleshy cheeks.Eusauropoda
Eusauropoda (meaning "true sauropods") is a derived clade of sauropod dinosaurs. Eusauropods represent the node-based group that includes all descendant sauropods starting with the basal eusauropods of Shunosaurus, and possibly Barapasaurus, and Amygdalodon, but excluding Vulcanodon and Rhoetosaurus. The Eusauropoda was coined in 1995 by Paul Upchurch to create a monophyletic new taxonomic group that would include all sauropods, except for the vulcanodontids.Eusauropoda are herbivorous, quadrupedal, and have long necks. They have been found in South America, Europe, North America, Asia, Australia, and Africa. The temporal range of Eusauropoda ranges from the early Jurassic to the Latest Cretaceous periods. The most basal forms of eusauropods are not well known and because the cranial material for the Vulcanodon is not available, and the distribution of some of these shared derived traits that distinguish Eusauropoda is still completely clear.Forest Sandstone
The Forest Sandstone is a geological formation in southern Africa, dating to roughly between 200 and 190 million years ago and covering the Hettangian to Sinemurian stages of the Jurassic Period in the Mesozoic Era. As its name suggests, it consists mainly of sandstone.
Fossils of the prosauropod dinosaur Massospondylus and the primitive sauropod Vulcanodon have been recovered from the Forest Sandstone.Gongxianosaurus
Gongxianosaurus is a genus of basal sauropod dinosaur from the early Jurassic Period (Toarcian stage). The only species is Gongxianosaurus shibeiensis. Based on four fragmentary to complete specimens found in China (Sichuan Province), it is one of the most completely known early sauropods. The skeleton is known in large part, missing both the hand and the majority of the skull. Gongxianosaurus was firstly named and described in a short note published in 1998; however, a comprehensive description has yet to be published. Gongxianosaurus shibeiensis was named for the place it was found, near the village Shibei in Gong County (珙县; Pinyin: Gǒng Xiàn).Gravisauria
Gravisauria is a clade of sauropod dinosaurs consisting of some genera, Vulcanodontidae and Eusauropoda.Kotasaurus
Kotasaurus ( KOH-tə-SAWR-əs; meaning "Kota Formation lizard") is a genus of sauropod dinosaur from the Early Jurassic period (Sinemurian–Pliensbachian). The only known species is Kotasaurus yamanpalliensis. It was discovered in the Kota Formation of Telangana, India and shared its habitat with the related Barapasaurus. So far the remains of at least 12 individuals are known. The greater part of the skeleton is known, but the skull is missing, with the exception of two teeth. Like all sauropods, it was a large, quadrupedal herbivore with long neck and tail.Ledumahadi
Ledumahadi (meaning "a giant thunderclap" in Sesotho language) is a genus of lessemsaurid sauropodomorph dinosaur from the Early Jurassic Elliot Formation in Free State Province, South Africa. The type and only species is L. mafube, known from a singular incomplete postcranial specimen. A quadruped, it was one of the first giant sauropodomorphs, reaching a weight of around 12 tonnes (26,000 lb), despite not having evolved columnar limbs like its later huge relatives.Neosauropoda
Neosauropoda is a clade within Dinosauria, coined in 1986 by Argentine paleontologist José Bonaparte and currently described as Saltasaurus loricatus, Diplodocus longus, and all animals directly descended from their most recent common ancestor. The group is composed of two subgroups: Diplodocoidea and Macronaria. Arising in the early Jurassic and persisting until the Cretaceous-Paleogene extinction event, Neosauropoda contains the majority of sauropod genera, including genera such as Apatosaurus, Brachiosaurus, and Diplodocus. It also includes giants such as Argentinosaurus, Patagotitan and Sauroposeidon, and its members remain the largest land animals ever to have lived.When Bonaparte first coined the term Neosauropoda in 1986, he described the clade as comprising “end-Jurassic” sauropods. While Neosauropoda does appear to have originated at the end of the Jurassic period, it also includes members through the end of the Cretaceous. Neosauropoda is currently delineated by specific shared, derived characteristics rather than the time period in which its members lived. The group was further refined by Upchurch, Sereno, and Wilson, who have identified thirteen synapomorphies shared among neosauropods. As Neosauropoda is a subgroup of Sauropoda, all members also display basic sauropod traits such as large size, long necks, and columnar legs.Omeisaurus
Omeisaurus (meaning "Omei lizard") is a genus of sauropod dinosaur from the Middle Jurassic Period (Bathonian-Callovian stage) of what is now China. Its name comes from Mount Emei, where it was discovered in the lower Shaximiao Formation of Sichuan Province.
Like other sauropods, Omeisaurus was herbivorous and large. It measured 20.2 metres (66 ft) long, and weighed 9.8 tonnes.Shunosaurus
Shunosaurus, meaning "shu lizard", is a genus of sauropod dinosaur from Early Jurassic (Oxfordian) beds in Sichuan Province in China, approximately 159±2 million years ago. The name derives from "Shu", an ancient name for the Sichuan province.Tambatitanis
Tambatitanis is an extinct genus of titanosauriform dinosaur from the Early Cretaceous (probably early Albian) of Japan. It is known from a single type species, Tambatitanis amicitiae. It was probably around 14 meters long and its mass was estimated at some 4 tonnes. It was a basal titanosauriform and possibly belonged to the Euhelopodidae.Tastavinsaurus
Tastavinsaurus is a genus of sauropod dinosaur belonging to the Titanosauriformes. It is based on a partial skeleton from the Early Cretaceous of Spain. The type species is Tastavinsaurus sanzi, named in honor of the Rio Tastavins in Spain and Spanish paleontologist José Luis Sanz.Tazoudasaurus
Tazoudasaurus is a genus of vulcanodontid sauropod dinosaurs hailing from the Early Jurassic Toundoute Group located in the High Atlas Mountains of Morocco in North Africa. The remains, consisting of a partial adult skeleton and associated partial juvenile skeleton found in continental detrital sediments of the Toarcian aged Toundoute Continental Series, were described by Ronan Allain et al. in early 2004. The generic name derives from one of the localities, Tazouda, while the specific descriptor is a latinization of the Arabic term for "slender" due to the animal's small size for a sauropod. Its fossil was found alongside that of Berberosaurus.
Tazoudasaurus, a small sauropod at 9 meters (30 feet) long, is characterized by rather primitive features such as the prosauropod-like mandible with spatulate and denticle-bearing teeth, lack of a U-shaped mandibular symphysis as other more derived sauropods. Teeth wear in V-shaped marks indicates tooth occlusion, suggesting that vulcanodontids processed food orally when feeding. The neck is flexible with elongate vertebrae that lack true pleurocoels while dorsal and caudal vertebrae series tend to be more rigid. T. naimi bears the most complete fossil skeleton for Early Jurassic sauropod remains found to date due to the scarcity of exposed strata of that age. This sauropod is most closely related to Vulcanodon, differing only in caudal vertebrae features while it also possesses characters that place it outside Eusauropoda.Tengrisaurus
Tengrisaurus (meaning "Tengri lizard") is a genus of lithostrotian sauropod, from the Early Cretaceous (Barremian-Aptian), of the Murtoi Formation, Russia. It was described in 2017 by Averianov & Skutschas. The type species is T. starkovi.Vulcanodontidae
The Early Jurassic sauropod dinosaurs Zizhongosaurus, Barapasaurus, Tazoudasaurus, and Vulcanodon may form a natural group of basal sauropods called the Vulcanodontidae. Basal vulcanodonts include some of the earliest known examples of sauropods. The family-level name Vulcanodontidae was erected by M.R. Cooper in 1984. In 1995 Hunt et al. published the opinion that the family is synonymous with the Barapasauridae. One of the key morphological features specific to the family is an unusually narrow sacrum.