Massospondylidae is a family of early massopod dinosaurs that existed in Asia, Africa, South America and Antarctica during the Late Triassic to the Early Jurassic periods. Several dinosaurs have been classified as massospondylids over the years. The largest cladistic analysis of early sauropodomorphs, which was presented by Apaldetti and colleagues in November 2011, found Adeopapposaurus, Coloradisaurus, Glacialisaurus, Massospondylus, Leyesaurus and Lufengosaurus to be massospondylids. This result supports many previous analyses that tested fewer taxa. However, this analysis found the two recently described North American massopods, Sarahsaurus and Seitaad, and the South African Ignavusaurus to nest outside Massospondylidae, as opposed to some provisional proposals. Earlier in 2011, Pradhania, a sauropodomorph from India, was tested for the first time in a large cladistic analysis and was found to be a relatively basal massospondylid. Mussaurus and Xixiposaurus may also be included within Massospondylidae. In 2019, a specimen previously assigned to Massospondylus from South Africa was re-examined and found to belong to a separate genus that was named Ngwevu.
|An example of Massospondylidae, Adeopapposaurus|
Massospondylidae, which was first named by Huene in 1914, is a stem-based taxon. It was defined by Sereno as all animals more closely related to Massospondylus carinatus than to Plateosaurus engelhardti and Saltasaurus loricatus.
Adeopapposaurus (meaning "far eating lizard", in reference to its long neck) is a genus of prosauropod dinosaur from the Early Jurassic Cañón del Colorado Formation of San Juan, Argentina. It was similar to Massospondylus. Four partial skeletons with two partial skulls are known.The type specimen, PVSJ568, includes a skull and most of a skeleton to just past the hips. The form of the bones at the tips of the upper and lower jaws suggests it had keratinous beaks. The fossils now named Adeopapposaurus were first thought to represent South American examples of Massospondylus; while this is no longer the case, Adeopapposaurus is classified as a massospondylid. Adeopapposaurus was described in 2009 by Ricardo N. Martínez. The type species is A. mognai, referring to the Mogna locality where it was found.Avetheropoda
Avetheropoda, or "bird theropods", is a clade that includes carnosaurians and coelurosaurs to the exclusion of other dinosaurs.Coloradisaurus
Coloradisaurus (meaning "Colorados [from Los Colorados Formation] lizard") is a genus of massospondylid sauropodomorph dinosaur. It lived during the Late Triassic period (Norian to Rhaetian stages) in what is now La Rioja Province, Argentina. It is known from the holotype PVL 5904, nearly complete skull. It was discovered and collected from the upper section of the Los Colorados Formation of the Ischigualasto-Villa Unión Basin.Glacialisaurus
Glacialisaurus is a genus of massospondylid sauropodomorph dinosaur. It lived during the Early Jurassic period in what is now central Transantarctic Mountains of Antarctica. It is known from the holotype FMNH PR1823, a partial hind limb (foot) and from the referred material FMNH PR1822, a left femur.Gryponyx
Gryponyx (meaning "hooked-claw") is an extinct genus of massopod sauropodomorph known from southern Free State, central South Africa.Ignavusaurus
Ignavusaurus is a genus of basal sauropodomorph dinosaur that lived during the Early Jurassic in what is now Lesotho. Its fossils were found in the Upper Elliot Formation which is probably Hettangian in age (around 200 million years ago). It was described on the basis of a partial, well preserved articulated skeleton. The type species, I. rachelis, was described in 2010 by Spanish palaeontologist F. Knoll.Leyesaurus
Leyesaurus is an extinct genus of massospondylid sauropodomorph dinosaur known from the San Juan Province, northwestern Argentina.Lufengosaurus
Lufengosaurus (Chinese: 祿豐龍 or 禄丰龙, meaning "Lufeng lizard") is a genus of massospondylid dinosaur which lived during the Early Jurassic period in what is now southwestern China. The dinosaur made international headlines in 2017 when Nature Communications reported scientists' discovery of 195-million-year-old collagen protein in the rib of a Lufengosarus fossil.Massospondylus
Massospondylus ( mas-oh-SPON-di-ləs; from Greek, μάσσων (massōn, "longer") and σπόνδυλος (spondylos, "vertebra")) is a genus of sauropodomorph dinosaur from the Early Jurassic Period (Hettangian to Pliensbachian ages, ca. 200–183 million years ago). It was described by Sir Richard Owen in 1854 from remains discovered in South Africa, and is thus one of the first dinosaurs to have been named. Fossils have since been found at other locations in South Africa, Lesotho, and Zimbabwe. Material from Arizona's Kayenta Formation, India, and Argentina has been assigned to this genus at various times, but the Arizonan and Argentinian material are now assigned to other genera.
The type species is M. carinatus; seven other species have been named during the past 150 years, but only M. kaalae among these is still considered valid. Early sauropodomorphs systematics have undergone numerous revisions during the last several years, and many scientists disagree where exactly Massospondylus lies on the dinosaur evolutionary tree. The family name Massospondylidae was once coined for the genus, but because knowledge of early sauropodomorph relationships is in a state of flux, it is unclear which other dinosaurs—if any—belong in a natural grouping of massospondylids; several 2007 papers support the family's validity.
Although Massospondylus was long depicted as quadrupedal, a 2007 study found it to be bipedal. It was probably a plant eater (herbivore), although it is speculated that the early sauropodomorphs may have been omnivorous. This animal, which was 4–6 metres (13–20 ft) long, had a long neck and tail, with a small head and slender body. On each of its forefeet, it bore a sharp thumb claw that was used in defense or feeding. Recent studies indicate that Massospondylus grew steadily throughout its lifespan, possessed air sacs similar to those of birds, and may have cared for its young.Mussaurus
Mussaurus (meaning "mouse lizard") is a genus of herbivorous sauropodomorph dinosaur that lived in southern Argentina during the Late Triassic, about 215 million years ago. It receives its name from the small size of the skeletons of juvenile and infant individuals, which were once the only known specimens of the genus. However, since Mussaurus is now known from adult specimens, the name is something of a misnomer; adults possibly reached 6 metres (20 ft) in length and weighed more than 1,000 kilograms (2,200 lb). Mussaurus possesses anatomical features suggesting a close, possibly transitional evolutionary relationship with true sauropods.Ngwevu
Ngwevu intloko (pronounced 'Ng-g'where-voo; directly from Xhosa 'ngwevu' and 'intloko' meaning "grey skull") is a genus of massospondylid sauropodomorph dinosaur from the Lower Jurassic Elliot Formation of South Africa. The type and only known specimen, BP/1/4779, was discovered in 1978 by James William Kitching. It had in 1990 and 2004 been regarded as an unusual specimen of the related Massospondylus, with a horizontally and vertically compressed skull, but in 2019 the specimen was after restudy concluded to belong to a new distinct genus. The genus is primarily distinguished by its skull being more robust than that of Massospondylus.Plateosauria
Plateosauria is a clade of sauropodomorph dinosaurs which lived during the Late Triassic to the Late Cretaceous. The name Plateosauria was first coined by Gustav Tornier in 1913. The name afterwards fell out of use until the 1980s.
Plateosauria is a node-based taxon. In 1998, Paul Sereno defined Plateosauria as the last common ancestor of Plateosaurus engelhardti and Massospondylus carinatus, and its descendants. Peter Galton and Paul Upchurch in 2004 used a different definition: the last common ancestor of Plateosaurus engelhardti and Jingshanosaurus xinwaensis, and its descendants. In their cladistic analysis the Plateosauria belonged to the Prosauropoda, and included the Plateosauridae subgroup. In Galton's and Upchurch's study also Coloradisaurus, Euskelosaurus, Jingshanosaurus, Massospondylus, Mussaurus, Sellosaurus, and Yunnanosaurus proved to be plateosaurians.However, recent cladistic analyses suggest that the Prosauropoda as traditionally defined is paraphyletic to sauropods. Prosauropoda, as currently defined, is a synonym of Plateosauridae as both contain the same taxa by definition.
The following cladogram simplified after an analysis presented by Apaldetti and colleagues in 2011.
The following cladogram simplified after an analysis presented by Blair McPhee and colleagues in 2014.Pradhania
Pradhania is a genus of massospondylid sauropodomorph dinosaur from the Sinemurian-age (Early Jurassic) Upper Dharmaram Formation of India. It was first named by T. S. Kutty, Sankar Chatterjee, Peter M. Galton and Paul Upchurch in 2007 and the type species is Pradhania gracilis. It was a sauropodomorph of modest size, only about four meters (13 ft) long, and is known from fragmentary remains. It was originally regarded as a basal sauropodomorph but new cladistic analysis performed by Novas et al., 2011 suggests that Pradhania is a massospondylid. Pradhania presents two synapomorphies of Massospondylidae recovered in their phylogenetic analysis.Pulanesaura
Pulanesaura is an extinct genus of basal sauropod known from the Early Jurassic (late Hettangian to Sinemurian) Upper Elliot Formation of the Free State, South Africa. It contains a single species, Pulanesaura eocollum, known from partial remains of at least two subadult to adult individuals.Riojasauridae
Riojasauridae is a family of sauropod-like dinosaurs from the Upper Triassic. It is known primarily from the genera Riojasaurus and Eucnemesaurus. Sites containing Riojasauridae include the Lower Elliot Formation of Orange Free State, South Africa (where fossils of Eucnemesaurus have been found), and Ischigualasto, in La Rioja Province, Argentina ( where fossils of Riojasaurus have been recovered).Sauropodomorpha
Sauropodomorpha ( SOR-ə-POD-ə-MOR-fə; from Greek, meaning "lizard-footed forms") is an extinct clade of long-necked, herbivorous, saurischian dinosaurs that includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had long necks and tails, were quadrupedal, and became the largest animals to ever walk the Earth. The "prosauropods", which preceded the sauropods, were smaller and were often able to walk on two legs. The sauropodomorphs were the dominant terrestrial herbivores throughout much of the Mesozoic Era, from their origins in the mid-Triassic (approximately 230 Ma) until their decline and extinction at the end of the Cretaceous (approximately 66 Ma).Seitaad
Seitaad is a genus of sauropodomorph dinosaur which lived during the lower Jurassic period in what is now southern Utah, United States.
Seitaad is known from an articulated partial postcranial holotype skeleton referred to as UMNH VP 18040. The skeleton is missing its head, neck and tail. It was collected from the Early Jurassic Navajo Sandstone, the uppermost unit of the Glen Canyon Group, dating to the Pliensbachian stage, near Comb Ridge, San Juan County. A phylogenetic study of Seitaad found it to be a plateosaur sauropodomorph, placing it in Massospondylidae or alternatively (a less probable position) in Plateosauridae, but its placement within the Plateosauria is not well understood. In a cladistic analysis, presented by Apaldetti and colleagues in November 2011, Seitaad was found to be within Massopoda, just outside Anchisauria.Seitaad was first described by Joseph J. W. Sertich and Mark A. Loewen in 2010 and the type species is Seitaad ruessi. The generic name is derived from Séít‘áád (Navajo language), a mythological sand monster from the Diné folklore who buried its victims in dunes. Seitaad appears to have been entombed by the collapse of a sand dune. The specific name honours Everett Ruess, a young artist, poet and naturalist, who mysteriously disappeared in 1934 while exploring southern Utah. Seitaad is the second basal sauropodomorph dinosaur to have been identified in North America.Xingxiulong
Xingxiulong (meaning "Xingxiu Bridge dragon") is a genus of bipedal sauropodiform from the Early Jurassic of China. It contains a single species, X. chengi, described by Wang et al. in 2017 from three specimens, two adults and an immature individual, that collectively constitute a mostly complete skeleton. Adults of the genus measured 4–5 metres (13–16 ft) long and 1–1.5 metres (3 ft 3 in–4 ft 11 in) tall. Phylogenetic analysis suggests that Xingxiulong is most closely related to its contemporary Jingshanosaurus, although an alternative position outside of both the Sauropodiformes and Massospondylidae is also plausible.
Despite their close relationship, Xingxiulong prominently differs from Jingshanosaurus - and from most basal sauropodomorphs - in having a number of sauropod-like traits. These include a sacrum containing four vertebrae; a pubis with an exceptionally long top portion; and the femur, the first and fifth metatarsals on the foot, and the scapula being wide and robust. These probably represent adaptations to supporting high body weight, in particular a large gut. Unlike sauropods, however, Xingxiulong would still have been bipedal.