Massospondylus ( ; from Greek, (massōn, "longer") and (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.
Introduction
Massospondylus
Massospondylus | Introduction
Genus of sauropodomorph dinosaur Is a genus of sauropodomorph dinosaur from the Early Jurassic Period A genus of sauropodomorph dinosaur from the Early Jurassic Period A genus of sauropodomorph dinosaur from the Early Jurassic Period
what is massospondylus?
user
This discovery therefore "sheds some light in the evolutionary pathways through which the peculiar adaptations of giant dinosaurs were attained", stated French paleontologist Eric Buffetaut.
Massospondylus | Reproduction
hislopi". The following cladogram shows the position of "Massospondylus" within Massospondylidae, according to Fernando E. Novas and colleagues, 2011:
Massospondylus | Classification
Massospondylus ( ; from Greek, (massōn, "longer") and (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.
Massospondylus | Introduction
"Massospondylus" was a mid-size sauropodomorph, around in length and weighed approximately 1000 kilograms (2200 lb), although a few sources have estimated its length at up to . It was a typical early sauropodomorph, with a slender body, a long neck and a proportionally very small head. The vertebral column was composed of nine cervical (neck) vertebrae, 13 dorsal (back) vertebrae, three sacral (hip) vertebrae, and at least 40 caudal (tail) vertebrae. The pubis faced forward, as with most saurischians. It had a slighter build than that of "Plateosaurus", an otherwise similar dinosaur. The neck was proportionally longer than in most other plateosaurids, with the foremost cervicals being four times the length of their width.
Massospondylus | Description
It was probably a plant eater (herbivore), although it is speculated that the early sauropodomorphs may have been omnivorous. This animal, which was 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.
Massospondylus | Introduction
However, the difference in length may be a misinterpretation based on crushing in a top–bottom plane, and the possession of a beak is considered unlikely in recent studies.
Massospondylus | Cranial anatomy
Teeth closer to the front of the snout had round cross-sections and tapered to points, unlike the back teeth, which were spatulate and had oval cross-sections. As with other early sauropodomorphs, it has been proposed that "Massospondylus" had cheeks. This theory was proposed because there are a few large holes for blood vessels on the surfaces of the jaw bones, unlike the numerous small holes present on the jaws of cheekless reptiles. The cheeks would have prevented food from spilling out when "Massospondylus" ate. Crompton and Attridge (1986) described skulls of "Massospondylus" as possessing pronounced overbites and suggested the presence of a horny beak on the tip of the lower jaw to make up the difference in length and account for tooth wear on the teeth at the tip of the snout.
Massospondylus | Cranial anatomy
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".
Massospondylidae | Introduction
Under the rules of zoological nomenclature, these names are junior synonyms. They were named after "Massospondylus" was described in a scientific paper; the name "Massospondylus" thus takes priority. "Ignavusaurus", known from a young specimen, was considered by Yates et al. (2011) to be a probable synonym of "Massospondylus". Cladistic analyses by Chapelle & Choiniere (2018) and Chapelle et al. (2019) agreed with Yates et al. (2011) in demonstrating the massospondylid nature of "Ignavusaurus", but nevertheless recovered it as a distinct taxon of massospondylid.
Massospondylus | Dubious names
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.
Massospondylus | Introduction
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". The following simplified cladogram is based on an analysis presented by Chappel and colleagues in 2019. Below is a simplified cladogram after Müller, 2019.
Massospondylidae | Phylogeny
"Massospondylus" had also been reported from Argentina, but this has been reassessed as a closely related but distinct genus. The fossils included several partial skeletons and at least one skull, found in the Lower Jurassic Canon del Colorado Formation of San Juan, Argentina. This material was named "Adeopapposaurus" in 2009. A specimen from South Africa previously assigned to "Massospondylus", BP/1/4779, became the holotype of the new genus and species "Ngwevu intloko" in 2019.
Massospondylus | History of discovery
Several genera have been previously synonymized with "Massospondylus". These include the above-mentioned "Leptospondylus" and "Pachyspondylus", as well as "Aristosaurus", "Dromicosaurus", "Gryponyx taylori" and "Hortalotarsus", which are dubious names of little scientific value. Together with "Massospondylus carinatus", Owen named "Leptospondylus capensis" and "Pachyspondylus orpenii" for vertebrae from the same unit and location. "Aristosaurus erectus" was named by E.C.N. van Hoepen in 1920 based on a nearly complete skeleton, and Hoepen also named "Dromicosaurus gracilis", which consisted of a partial skeleton. "Gryponyx taylori" was named by Sidney H. Haughton in 1924. It consists of hip bones. All of the above fossils come from the Hettangian or Sinemurian faunal stages of South Africa, where "Massospondylus" has been found.
Massospondylus | Dubious names
As with all dinosaurs, much of the biology of "Massospondylus", including its behavior, coloration, and physiology, remains unknown. However, recent studies have allowed for informed speculation on subjects such as growth patterns, diet, posture, reproduction, and respiration. A 2007 study suggested that "Massospondylus" may have used its short arms for defense against predators ("defensive swats"), in intraspecies combat, or in feeding, although its arms were too short to reach its mouth. Scientists speculate that "Massospondylus" could have used its large pollex (thumb) claw in combat, to strip plant material from trees, digging, or for grooming.
Massospondylus | Paleobiology
The forelimbs were only half the length of the hindlimbs but quite powerful, as indicated by the broad upper end of the humerus that provided attachment areas for a large arm musculature. Like "Plateosaurus", it had five digits on each hand and foot. The hand was short and wide, with a large sickle shaped thumb claw used for feeding or defense against predators. The thumb was the longest finger in the hand, while the fourth and fifth digits were tiny, giving the forepaws a lopsided look.
Massospondylus | Description
Massaliasuchus is an extinct genus of allodaposuchid crocodylian that is known from fossils found in Santonian–Campanian-age Upper Cretaceous rocks of southeastern France.
Massaliasuchus | Introduction
Massospondylidae is a family of early massopod dinosaurs that existed in Asia, Africa, North America, 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.
Massospondylidae | Introduction
The neck was short, contrasting to the very long neck in the adults. Girdle bones and caudals were relatively tiny. The forelimbs were of equal length to the hindlimbs, indicating that newly hatched "Massospondylus" were quadrupedal, unlike the bipedal adults. The discovery of hatching footprints with manus impressions confirmed their quadrupedality. These impressions show that the hand was not pronated, with palm faces facing each other and the thumb facing forwards. The unpronated manus and the big head indicate that an effective locomotion was not possible for newly hatched "Massospondylus". Notably, the near-hatchings had no teeth, suggesting they had no way of feeding themselves.
Massospondylus | Reproduction
All these bones were found disarticulated, making it difficult to determine if all material belongs to a single species or not. However, Owen was able to distinguish three different types of caudal vertebrae, which he attributed to three different genera: "Pachyspondylus", "Leptospondylus" and "Massospondylus". "Massospondylus" was separated from the other two genera on the basis of its much longer caudal vertebrae, which also led to the scientific name that has been derived from the Greek terms "masson"/μάσσων 'longer' and "spondylos"/σπόνδυλος 'vertebra', explained by Owen as "because the vertebrae are proportionally longer than those of the extinct Crocodile called "Macrospondylus"". However, later it was shown that the putative caudal vertebrae of "Massospondylus" were actually cervical vertebrae and that all the material probably belongs only to a single species.
Massospondylus | History of discovery
Sedimentary structures indicate that the nesting area was in the vicinity of a lake. The eggshells were very thin (about 0.1 mm), allowing gas exchange even in a low oxygen and carbon dioxide rich environment, which indicates that the eggs were at least partly buried in the substrate. There are no hints that "Massospondylus" constructed nests; however, the arrangement of the eggs in tight rows indicates that the eggs were pushed in this position by the adults. The embryos probably represented near-hatchlings. While the skeletal features were similar to those of the adults, the body proportions were very dissimilar. The head was big with a short snout and very large orbits, whose diameter amounts 39% of the entire skull length.
Massospondylus | Reproduction
The small head of "Massospondylus" was approximately half the length of the femur. Numerous openings, or fenestrae, in the skull reduced its weight and provided space for muscle attachment and sensory organs. These fenestrae were present in pairs, one on each side of the skull. At the front of the skull were two large, elliptical nares, which were roughly half the size of the orbits. The orbits were proportionally larger in "Massospondylus" than in related genera, such as "Plateosaurus". The antorbital fenestrae, smaller than those seen in "Plateosaurus", were situated between the eyes and the nose. At the rear of the skull were two more pairs of temporal fenestrae: the lateral temporal fenestrae immediately behind the eye sockets, which were shaped like an inverted "T" in "Massospondylus", and the supratemporal fenestrae on top of the skull.
Massospondylus | Cranial anatomy
The first fossils of "Massospondylus" were described by paleontologist Sir Richard Owen in 1854. Originally, Owen did not recognize these finds as those of a dinosaur; instead he attributed them to "large, extinct, carnivorous reptiles" that were related to today's lizards, chameleons and iguanas. This material, a collection of 56 bones, was found in 1853 by the government surveyor Joseph Millard Orpen in the Upper Elliot Formation at Harrismith, South Africa and was donated to the Hunterian Museum at the Royal College of Surgeons in London. Among the remains were vertebrae from the neck, back, and tail; a shoulder blade; a humerus; a partial pelvis; a femur; a tibia; and bones of the hands and feet.
Massospondylus | History of discovery
Bonnan and Yates (2007) considered "Camelotia", "Blikanasaurus" and "Melanorosaurus" possible sauropods. Yates (2007) placed "Antetonitrus", "Melanorosaurus", and "Blikanasaurus" as basal sauropods and declined to use the term Prosauropoda, as he considered it synonymous with Plateosauridae. However, he did not rule out the possibility that a small group of prosauropods consisting of "Plateosaurus", "Riojasaurus", "Massospondylus" and their closest kin were monophyletic. "Massospondylus" is the type genus of the proposed family Massospondylidae, to which it gives its name. The Massospondylidae may also include "Yunnanosaurus", although Lu "et al." (2007) placed "Yunnanosaurus" in its own family. Yates (2007) considered "Massospondylus", "Coloradisaurus", and "Lufengosaurus" massospondylids, with "Yunnanosaurus" in Anchisauria.
Massospondylus | Classification
The most recent suggestion is that it is a stem chondrichthyan.
Palaeospondylus | Introduction
Eustreptospondylus ( ; meaning "true "Streptospondylus"") is a genus of megalosaurid theropod dinosaur, from the Oxfordian stage of the Late Jurassic period (some time between 163 and 154 million years ago) in southern England, at a time when Europe was a series of scattered islands (due to tectonic movement at the time which raised the sea-bed and flooded the lowland).
Eustreptospondylus | Introduction
Marmarospondylus ("marble [reference to the Forest Marble Formation] vertebra") is a dubious genus of sauropod dinosaur from Middle Jurassic deposits in the English Midlands. The type species, "Marmarospondylus robustus", was described by Richard Owen as a species of the Late Jurassic genus "Bothriospondylus" in 1875. The holotype, NHMUK R.22428, a dorsal, was found in the Bathonian-age Forest Marble Formation at Bradford-on-Avon, Wiltshire. Owen himself in an addendum to the same publication coined "Marmarospondylus" for "B. robustus", presumably due to its being older than "B. suffosus". Recent publications have treated "Marmarospondylus" as a dubious member of Macronaria.
Marmarospondylus | Introduction
This synonymy is no longer accepted. "M. kaalae" was described in 2009 on the basis of a partial skull from the Upper Elliot Formation in Eastern Cape of South Africa. This species is known from the same time and region as some specimens of "M. carinatus". It differs from the type species in the morphology of the braincase, as well as in several other characters of the skull such as the proportions of the premaxilla.
Massospondylus | Species
A 2005 study indicated that "Massospondylus"' sister taxon, "Plateosaurus", exhibited growth patterns affected by environmental factors. The study indicated that, when food was plentiful or when the climate was favorable, "Plateosaurus" exhibited accelerated growth. This pattern of growth is called "developmental plasticity". It is unseen in other dinosaurs, including "Massospondylus", despite the close relationship between the two. The study indicated that "Massospondylus" grew along a specific growth trajectory, with little variation in the growth rate and ultimate size of an individual. Another study of age determination indicated that "Massospondylus" grew at a maximum rate of 34.6 kg (76.3 lb) per year and was still growing at around 15 years of age.
Massospondylus | Growth
"M. harriesi" is known from a well-preserved forelimb and parts of a hindlimb. "M. schwarzi" is known from an incomplete hind limb and sacrum. "M. hislopi" and "M. rawesi" were named from fossils found in India. "M. hislopi" is based on vertebrae from the Upper Triassic Maleri Formation of Andhra Pradesh, whereas "M. rawesi" is based on a tooth from the Upper Cretaceous Takli Formation of Maharashtra. "M. hislopi" was tentatively retained as an indeterminate sauropodomorph in the latest review, but "M. rawesi" may be a theropod or nondinosaur. "M. huenei" is a combination derived by Cooper for "Lufengosaurus huenei", as he considered "Lufengosaurus" and "Massospondylus" to be synonyms.
Massospondylus | Species
Although its mass suggests a quadrupedal nature, "Massospondylus" would have been restricted to its hind legs for locomotion. Since the discovery of rudimentary and nonfunctional clavicles in ceratopsians, it was assumed that these shoulder bones were reduced in all dinosaurs that did not have true furculae. Robert Bakker (1987) suggested that this would have allowed the shoulder blades to swing with the forelimbs in quadrupedal dinosaurs, increasing their functional forelimb length. This would have reduced the discrepancy of length between fore- and hindlimbs in a quadrupedal "Massospondylus". However, a recent discovery shows that "Massospondylus" possessed well-developed clavicles that were joined in a furcula-like arrangement, acting like a clasp between the right and left shoulder blades and prohibiting any rotation of these bones.
Massospondylus | Gait and range of motion
Yates assigned the Massopoda to Plateosauria. Within the clade, he assigned the families Massospondylidae (which includes the relatively well-known dinosaur "Massospondylus") and Riojasauridae (which includes "Riojasaurus") as well as the Sauropoda. The following is a simplified cladogram from an analysis presented by Blair McPhee and colleagues in 2014:
Massopoda | Classification
Smith and Pol (2007) also found a Massospondylidae in their phylogenetic analysis, including "Massospondylus", "Coloradisaurus", and "Lufengosaurus", as well as their new genus, "Glacialisaurus". "Adeopapposaurus", based on the fossils once thought to belong to a South American form of "Massospondylus", was also classified as a massospondylid, as was "Leyesaurus", another South American genus that was named in 2011. "Pradhania" was originally regarded as a more basal sauropodomorph but new cladistic analysis performed by Novas "et al.", 2011 suggests that "Pradhania" is a massospondylid. "Pradhania" presents two shared traits of the Massospondylidae recovered in their phylogenetic analysis, and the fossils of "Pradhania" were discovered from the same region and basin in India as "M.
Massospondylus | Classification
However, newer finds revealed a diverse contemporary sauropodomorph fauna with six additional species, including "Ignavusaurus", "Arcusaurus" and two unnamed taxa as well as two unnamed sauropods. It is not clear which carnivores may have preyed on "Massospondylus". Most of the theropods that have been discovered in rocks of Early Jurassic age in southern Africa, such as "Coelophysis", were smaller than mid-sized sauropodomorphs like "Massospondylus". These smaller predators have been postulated as using fast slashing attacks to wear down sauropodomorphs, which could have defended themselves with their large hand and foot claws. The 6-metre-(20 ft-) long carnivorous theropod "Dracovenator" lived during the same period (Hettangian to Sinemurian stages) as "Massospondylus" and has also been found in the Elliot Formation of South Africa.
Massospondylus | Paleoecology
The present individuals probably represented juveniles as indicated by small size and open bone sutures. From detailed features the describers concluded these were not juveniles of either "Aardonyx" or "Massospondylus".
Arcusaurus | Discovery
Bathyspondylus is an extinct genus of plesiosaur. It was first described in 1982 from a specimen originally found in 1774, now housed at the Devizes Museum. Because it is known only from its fossil vertebrae (and so few of those have been recovered), paleontologists are not entirely sure of the taxonomy of "Bathyspondylus"; the family it belongs to is not currently known. The type, and only known, species is B. swindoniensis, which was described from the same material as its genus.
Bathyspondylus | Introduction
On May 10, 1941, the Hunterian Museum was demolished by a German bomb, destroying all the fossils; only casts remain. Because the plaster casts of the lost type specimen fossils were not adequate to accurately diagnose a genus and species under modern taxonomic practices and for research purposes, Yates and Barrett (2010) designated BP/1/4934, a skull and a largely complete postcranial skeleton in the Bernard Price Institute for Palaeontological Research, as the neotype specimen. "Massospondylus" remains have been found in the Upper Elliot Formation, the Clarens Formation, and the Bushveld Sandstone of South Africa and Lesotho, as well as the Forest Sandstone of Zimbabwe.
Massospondylus | History of discovery
estimated the body mass of two specimens to be .
Phlaocyon achoros | Body mass
In the most recent review, it was considered to be a dubious ceratosaurian. ""Massospondylus"" "rawesi", another tooth taxon, but from probable Upper Triassic rocks, is sometimes given as a second species of this genus, but it may not be dinosaurian, and could be substantially older.
Orthogoniosaurus | Introduction
It consist of an elongated natural internal cast or endocast of the neural canal of the sacrum, about sixty centimetres long. It shows the divisions of at least five and probably seven sacral vertebrae. On three of them the cancellous bone is still present to which the generic name is referring. It is the only known fossil that can be definitely assigned to this genus.
Thecospondylus | Introduction
Many species have been named, although most are no longer considered valid. "M. carinatus", named by Richard Owen, is the type species. Other named species include: "M. browni" Seeley, 1895, "M. harriesi" Broom 1911, "M. hislopi" Lydekker, 1890, "M. huenei" Cooper, 1981, "M. kaalae" Barrett 2009, "M. rawesi" Lydekker, 1890, and "M. schwarzi" Haughton, 1924. "M. browni", "M. harriesi", and "M. schwarzi" were all found in the Upper Elliot Formation of Cape Province, South Africa. All three are based on fragmentary material, and were regarded as indeterminate in the most recent review. "M. browni" is based on two cervical, two back, and three caudal vertebrae and miscellaneous hind limb elements.
Massospondylus | Species
The main specimen of "Eustreptospondylus" was not fully grown, and according to an estimate by Paul in 1988 was about long and weighed about . Various estimates suggest that "Eustreptospondylus" was an "average-sized" theropod, with a hypothetical adult length of around , and a mass of . The skull of "Eustreptospondylus" has a rather pointed snout in side view, with a large horizontally oriented nostril. There is no lacrimal horn. The skull roof is relatively thick. Oblique grooves in the jaw joints caused the gape of the mouth to be widened when the lower jaws were opened. These jaws at the front are rather tall and wide.
Eustreptospondylus | Description
Based on the lack of teeth and the ineffective locomotion, scientists speculate that postnatal care might have been necessary. This is further supported by evidence that the hatchings remained at the nest sites until they had doubled in size. Newly hatched juveniles are known from a second sauropodomorph, "Mussaurus"; these remains resemble those of the embryonic "Massospondylus", suggesting that quadrupedality was present in newly hatched "Mussaurus" and presumably other basal sauropodomorphs as well. The quadrupedality of the hatchings suggests that the quadrupedal posture of later sauropods may have evolved from retention of juvenile characteristics in adult animals, an evolutionary phenomenon known as pedomorphosis.
Massospondylus | Reproduction
"Koolasuchus" was an aquatic temnospondyl estimated to have been around in length. Its mass has been estimated to be up to . Although represented by incomplete material, the skull was likely long. Like other chigutisaurids, it had a wide, rounded head and tabular horns projecting from the backside of the skull.
Koolasuchus | Description
Massicus pascoei is a species of round-necked longhorn beetles of the subfamily Cerambycinae.
Massicus pascoei | Introduction
Streptospondylus (meaning "reversed vertebra") is a genus of tetanuran theropod dinosaur known from the Late Jurassic period of France, 161 million years ago. It was a medium-sized predator with an estimated length of 6 meters (19.5 ft) and a weight of 500 kg (1,100lbs).
Streptospondylus | Introduction
In the early twenty-first century a new display changed this to a horizontal position of the body.
Eustreptospondylus | Discovery and naming
Megosmidus tuberculatus is a species of beetle in the family Cerambycidae, the only species in the genus Megosmidus.
Megosmidus | Introduction
The faunas and floras of the Early Jurassic were similar worldwide, with conifers adapted for hot weather becoming the common plants; basal sauropodomorphs and theropods were the main constituents of a worldwide dinosaur fauna. The environment of early Jurassic southern Africa has been described as a desert. African "Massospondylus" was a contemporary of temnospondyli; turtles; a sphenodontia; rauisuchids; early crocodylomorphs; tritylodontid and trithelodontid therapsids; morganucodontid mammals; and dinosaurs including the small theropod "Coelophysis rhodesiensis" and several genera of early ornithischians, such as "Lesothosaurus" and the heterodontosaurids "Abrictosaurus", "Heterodontosaurus", "Lycorhinus" and "Pegomastax". Until recently, "Massospondylus" was regarded as the only known sauropodomorph from the Upper Elliot Formation.
Massospondylus | Paleoecology
It has an estimated span of and a mass of .
57 Mnemosyne | Introduction
This discovery indicates that the clavicle reduction is limited to the evolutionary line leading to the ceratopsians. It also indicates that the furcula of birds is derived from clavicles. Michael Cooper (1981) noted that the zygapophyses of the neck vertebrae were inclined, prohibiting significant horizontal movement of the neck, so that "consequently any significant movement in this direction must have been accomplished by a change in the position of the entire body". This was contradicted in a recent study, noting that only the basalmost cervicals show inclined zygapophyses, allowing sufficient horizontal movement of the neck as a whole.
Massospondylus | Gait and range of motion
Basal sauropodomorph systematics continue to undergo revision, and many genera once considered classic "prosauropods" have recently been removed from the group in phylogenetic nomenclature, on the grounds that their inclusion would not constitute a clade (a natural grouping containing all descendants of a single common ancestor). Yates and Kitching (2003) published a clade consisting of "Riojasaurus", "Plateosaurus", "Coloradisaurus", "Massospondylus", and "Lufengosaurus". Galton and Upchurch (2004) included "Ammosaurus", "Anchisaurus", "Azendohsaurus", "Camelotia", "Coloradisaurus", "Euskelosaurus", "Jingshanosaurus", "Lessemsaurus", "Lufengosaurus", "Massospondylus", "Melanorosaurus", "Mussaurus", "Plateosaurus", "Riojasaurus", "Ruehleia", "Saturnalia", "Sellosaurus", "Thecodontosaurus", "Yimenosaurus" and "Yunnanosaurus" in a monophyletic Prosauropoda. Wilson (2005) considered "Massospondylus", "Jingshanosaurus", "Plateosaurus", and "Lufengosaurus" a natural group, with "Blikanasaurus" and "Antetonitrus" possible sauropods.
Massospondylus | Classification
There are 26 teeth in each side of the lower jaw in the largest known skull. The height of the teeth crowns decreases from front to back in the upper jaw, but was more or less constant in the lower jaw. The lack of pronounced tooth wear and the variable height of the crowns suggests that the teeth were replaced by succeeding new ones in relatively short time intervals. Notably, there was variation in the tooth morphology based on the position of the teeth in the jaw. The heterodonty present in "Massospondylus" is greater than that present in "Plateosaurus", although not as pronounced as the specialization of teeth in "Heterodontosaurus".
Massospondylus | Cranial anatomy
One study in 2007 concluded that basal sauropodomorphs like "Massospondylus" likely had abdominal and cervical air sacs, based on the evidence for them in sister taxa (theropods and sauropods). The study concluded that it was impossible to determine whether basal sauropodomorphs had a bird-like flow-through lung, but that the air sacs were almost certainly present.
Massospondylus | Respiratory system
"Massaliasuchus" was first described in 1869 by Philippe Matheron as "Crocodilus affuvelensis", based on remains including skull bones. The new genus name was given to it in 2008 by Jeremy Martin and Eric Buffetaut. "Massaliasuchus" was considered to be related to early alligatoroids. Its name means "Marseille crocodile". Recent cladistic analysis places "Massaliasuchus" as a member of Allodaposuchidae, a clade of basal eusuchians from the Late Cretaceous of southern Europe. The genus can be distinguished from "Musturzabalsuchus" in having 15 alveoli in the dentary.
Massaliasuchus | Systematics
"Ignavusaurus" is a basal sauropodomorph, a member of the long-necked, herbivorous, saurischian dinosaurs. Although originally recovered as more primitive than Plateosauria by Knoll (2010), Yates et al. (2011) noted that some characters used to place "Ignavusaurus" outside Massopoda are reflective of juvenile status and instead are more similar to juvenile "Massospondylus", considering "Ignavusaurus" probably synonymous with "Massospondylus". Meanwhile, a cladistic analysis presented by Apaldetti et al. (2011) found "Ignavusaurus" to be a valid genus which is most closely related to "Sarahsaurus" within Massopoda, somewhat agreeing with Yates et al. that "Ignavusaurus" is not as primitive as originally thought. A cladistic analysis conducted by Chapelle and Choiniere (2018) in their paper updating knowledge of the skull of "Massospondylus" recovered "Ignavusaurus" along with "Sarahsaurus" in Massospondylidae, as did the cladistic analysis of Chapelle et al.
Ignavusaurus | Classification
The Massopoda is a clade of sauropodomorph dinosaurs which lived during the Late Triassic to the Late Cretaceous periods. It was named by paleontologist Adam M. Yates of the University of the Witwatersrand in 2007. Massopoda is a stem-based taxon, defined as all animals more closely related to "Saltasaurus loricatus" than to "Plateosaurus engelhardti". The name Massopoda, ; , is also contraction of Massospondylidae and Sauropoda, two disparate taxa in the clade.
Massopoda | Introduction
estimated the body mass of two specimens to be .
Phlaocyon latidens | Body mass
Massetognathus ( ; Greek for "chewing muscle jaw") is an extinct genus of plant-eating traversodontid cynodonts. They lived during the Triassic Period about 235 million years ago, and are known from the Chañares Formation in Argentina and the Santa Maria Formation in Brazil.
Massetognathus | Introduction
Palaeos.com
Megasecoptera | Sources
"Borealosuchus" was a mid-sized crocodylian; "B. acutidentatus" reached up to in length with a skull.
Borealosuchus | Introduction
Omoglymmius massa is a species of beetle in the subfamily Rhysodidae. It was described by R.T. & J.R. Bell in 1982.
Omoglymmius massa | Introduction
"Koolasuchus" was one of the largest of the brachyopoids, with an estimated weight of .
Temnospondyli | Mesozoic
grandis" to a new genus, "Hypselohaptodus".
Hypselohaptodus | Introduction
"Massicus pascoei" can reach a body length of about and a body width of about . The basic color of the body is pale brown or greyish, with dense luteous pubescence. Prothorax is narrow and rugose and shows broad longitudinal hairy stripes. Elytra are elongated and gradually narrow posteriorly. Antennae are black, longer than the body.
Massicus pascoei | Description
Chonespondylus is an extinct genus of Ichthyosaur. It was formally described by Leidy in 1868.
Chonespondylus | Introduction
Euseius coccosocius is a species of mite in the family Phytoseiidae.
Euseius coccosocius | Introduction
The holotype specimen may represent a juvenile form of another diadectid. Because so little is known of the genus, the relationship of "Stephanospondylus" to other diadectids is poorly known.
Stephanospondylus | Description
The genus name "Bathyspondylus" is a compound of two Greek roots: βαθυς ("bathys") 'deep' and σπονδυλος ("spondylos") 'vertebra'. It can thus be translated as "deep-vertebrae". The species name "B. swindoniensis" refers to the town of Swindon in Wiltshire, near which the holotype specimen was discovered.
Bathyspondylus | Etymology
Haplosclerida is an order of demosponges. It contains the following families:
Haplosclerida | Introduction
Koumpiodontosuchus is an extinct genus of neosuchian crocodyliform that lived in the Early Cretaceous. The only species is K. aprosdokiti, named in 2015.
Koumpiodontosuchus | Introduction
Massicus is a genus of round-necked longhorn beetles of the subfamily Cerambycinae.
Massicus (genus) | Introduction
This was compounded by German palaeontologist Friedrich von Huene, who sometime referred to the specimen as "Streptospondylus cuvieri" and at other times considered it a species of "Megalosaurus": "Megalosaurus cuvieri". In 1964, Alick Donald Walker clarified matters by erecting a separate genus and species for the Oxford specimen: "Eustreptospondylus oxoniensis". The genus name "Eustreptospondylus", was intended to mean "true "Streptospondylus"". "Streptospondylus" means "turned vertebra", and is derived from the Greek words "streptos" (στρεπτος) meaning "reversed" and "spondylus" (σπονδυλος), a reference to the fact that its dorsal vertebrae were opisthocoelous, in contrast to the typical procoelous vertebrae of crocodiles. The specific name "oxoniensis", refers to its provenance from Oxford.
Eustreptospondylus | Discovery and naming
In 1997 it was suggested that due to this apparent similarity, along with the vagueness of descriptions in the 1869 paper and the loss of the syntype, that "C. affuvelensis" could be reassigned to "Musturzabalsuchus", although it was also acknowledged that the lack of posterior cranial material in the genus made detailed comparisons difficult. A recent 2008 study on Matheron's specimens concluded that they belonged to a new genus distinct from "Crocodylus" and different from "Musturzabalsuchus", named "Massaliasuchus". A recent phylogenetic analysis recovered "Musturzabalsuchus" as a member of Allodaposuchidae, outside Alligatoroidea.
Musturzabalsuchus | Phylogenetics
harriesi" is considered to be a "nomen dubium"). However, Vasconcelos and Yates (2004) found "Gryponyx" to be distinctive enough from other basal sauropodomorphs to be placed in its own genus. They found that it differs from other taxa by the following characteristics: total length of metacarpal I exceeds maximum proximal width and a long, narrow pubic apron with straight lateral margins. Although this publication wasn't formal, they conducted a cladistic analysis using Yates (2004) sauropodomorph matrix and found "Gryponyx" to be the most basal massospondylid. The same result was found by Lü Junchang "et al." (2010). Yates "et al." (2010) recovered "Gryponyx" in a trichotomy with Massospondylidae and Anchisauria.
Gryponyx | Description
Only photographs remain.
Stomatosuchus | Introduction
Collidosuchus is an extinct genus of archegosauroidean temnospondyl within the family Archegosauridae.
Collidosuchus | Introduction
This genus has simple sclerites with a single (small but prominent) node in the middle, so can be separated from "Palaeoscolex"(unless this simplicity is taphonomic). Its introvert has a six-fold symmetry, whereas its proboscis has quincuncially arranged teeth that resemble those of other Cambrian ecdysozoan worms.
Palaeoscolecid | Mafangscolex
In 1976, a clutch of seven 190-million-year-old "Massospondylus" eggs was found in Golden Gate Highlands National Park in South Africa by James Kitching, who identified them as most likely belonging to "Massospondylus". It was nearly 30 years before extraction was started on the fossils of the 15-centimetre- (6 in-) long embryos. They remain the oldest dinosaur embryos ever found. By early 2012, at least 10 egg clutches from at least four fossiliferous horizons had been found, with up to 34 eggs per clutch. This indicates that this nesting site may have been used repeatedly (site fidelity), by groups of animals (colonial nesting); in both cases, these represent the oldest evidence of this behaviour.
Massospondylus | Reproduction
Like all Agnostida, "Marocconus" is diminutive and the headshield (or cephalon) and tailshield (or pygidium) are of approximately the same size (or isopygous) and outline. Like all Weymouthiidae, it lacks eyes and rupture lines (or sutures). The cephalon is subcircular except for the straight posterior. The external surface of the cephalon is smooth, convex, and is hanging over an extremely narrow border. The central raised area of the cephalon (or glabella) is evident on the internal mold by a clear defining furrow, long triangular in outline (about 1⅓× as long as the maximum width), with rounded tips and only one transverse furrow (SO).
Marocconus | Description
Early sauropodomorphs such as "Massospondylus" may have been herbivorous or omnivorous. As recently as the 1980s, paleontologists debated the possibility of carnivory in the "prosauropods". However, the hypothesis of carnivorous "prosauropods" has been discredited, and all recent studies favor a herbivorous or omnivorous lifestyle for these animals. Galton and Upchurch (2004) found that cranial characteristics (such as jaw articulation) of most basal sauropodomorphs are closer to those of herbivorous reptiles than those of carnivorous ones, and the shape of the tooth crown is similar to those of modern herbivorous or omnivorous iguanas. The maximum width of the crown was greater than that of the root, resulting in a cutting edge similar to those of extant herbivorous or omnivorous reptiles.
Massospondylus | Diet
Megalosauripus is an ichnogenus that has been attributed to dinosaurs.
Megalosauripus | Introduction
The Phyllospondyli is a now abandoned term for a series of small, poorly ossified fossils of labyrinthodont amphibians from the Paleozoic. The groups was proposed as an order on the basis if their vertebrae, which was either consisting of neural arches over an otherwise unossified notocord or consisting of thin-walled, ring-shaped intercentra topped by the neural arch. The name "pyllospondily" is from Greek, "leaf vertebrae". While the group originally was based on the shape of the vertebrae, common in older classification of labyrinthodonts, several families was at times assigned to it based on skull characters. All members were more or less salamander-like in body outline, with weak, poorly ossified limbs, four fingers to the hand and a more or less round skull when seen from above.
Phyllospondyli | Introduction
The most recent revision of the metoposaurids by Adrian Hunt stated that the holotype was too fragmentary to be diagnostic and designated "D. elegans" as a "nomen dubium" within Temnospondyli
Dictyocephalus | Introduction
It is hollow and conical.
Tatankacephalus | Introduction
Plagiosuchus is an extinct genus of plagiosaurid temnospondyl. It is known from several collections from the Middle Triassic of Germany.
Plagiosuchus | Introduction
Conus globoponderosus is a fossil species of sea snail, a marine gastropod mollusk in the family Conidae, the cone snails, cone shells or cones.
Conus globoponderosus | Introduction
Stephanospondylus is an extinct genus of diadectid reptiliomorph from the Early Permian of Germany. Fossils have been found in deposits of the Lower Rotliegend near Dresden. The type species "S. pugnax" was originally referred to the genus "Phanerosaurus" in 1882 but was placed in its own genus in 1905.
Stephanospondylus | Introduction
Crocodylus is a genus in the family Crocodylidae. The scientific name was proposed by Josephus Nicolaus Laurenti in 1768.
Crocodylus | Introduction
Pelosuchus is a genus of Dinocephalian.
Pelosuchus | Introduction
Amblyseius crassicaudalis is a species of mite in the family Phytoseiidae.
Amblyseius crassicaudalis | Introduction
The generic name is a contraction of "Thecospondylus" and "Coelurus". The holotype, NHMUK PV R181, was found in debris from a layer of the Wessex Formation, dating from the Barremian. It consists of the anterior end, about a third, of a cervical vertebra estimated by Seeley to have been nine centimetres long.
Thecocoelurus | Discovery and naming
These remains consist of at least 80 partial skeletons and four skulls, representing both juveniles and adults. The report of "Massospondylus" from Arizona's Kayenta Formation is based on a skull described in 1985. The skull of the Kayenta specimen from Arizona is 25% larger than the largest skull from any African specimen. The Kayenta specimen possesses four teeth in the premaxilla and sixteen in the maxilla. Uniquely among dinosaurs, it also had tiny, one-millimetre-(0.04 in-) long palatal teeth. A 2004 restudy of African "Massospondylus" skulls, however, indicated that the Kayenta specimen did not pertain to "Massospondylus". This Kayenta skull and associated postcranial elements, identified collectively as MCZ 8893, was referred to the new genus "Sarahsaurus" in 2010.
Massospondylus | History of discovery
Prothoosuchus is an extinct genus of trematosaurian temnospondyl within the family Thoosuchidae.
Prothoosuchus | Introduction
Amblyseius megaporos is a species of mite in the family Phytoseiidae.
Amblyseius megaporos | Introduction
megacephalus", in order to describe "C. rugosus".
Craugastor rugosus | Description
Procoelambus macrocephalus is a species of beetle in the family Dytiscidae, the only species in the genus Procoelambus.
Procoelambus | Introduction
Hypselohaptodus is a genus of sphenacodont synapsid from the Cisuralian of England. It contains a single species, Hypselohaptodus grandis, and is known only from a single specimen, a partial left maxilla, which is hosted at the Warwick County Museum. It was collected at Kenilworth, Warwickshire, England, from the Kenilworth Sandstone Formation (Warwickshire Group), dating to the earliest Asselian stage of the Cisuralian series, about 299 million years ago. "H. grandis" was originally assigned to "Haptodus" by Paton in 1974. In 2015 it was determined that "H. grandis" and "Haptodus garnettensis" were not congeneric with "Haptodus baylei" and in 2019 reassigned "H.
Hypselohaptodus | Introduction
Palaeospondylus gunni (Gunn's ancient vertebrae) is a mysterious, fish-like fossil vertebrate. Its fossils are described from Achanarras slate quarry in Caithness, Scotland. The fossil as preserved is carbonized, and indicates an eel-shaped animal up to in length. The skull, which must have consisted of hardened cartilage, exhibits pairs of nasal and auditory capsules, with a gill apparatus below its hinder part, and ambiguous indications of ordinary jaws. The phylogeny of this bizarre fossil has puzzled scientists since its discovery in 1890, and many taxonomies have been suggested. In 2004, researchers proposed that "Palaeospondylus" was a larval lungfish. Previously, it had been classified as a larval tetrapod, unarmored placoderm, an agnathan, an early stem hagfish, and a chimera.
Palaeospondylus | Introduction
catacopsis".
Machairodus | Classification
The average mass of an adult "Prionosuchus" is estimated at over . With an elongated and tapered snout, numerous sharp teeth, long body, short legs, and a tail adapted for swimming, its general appearance was very similar to a modern gharial or gar, and it probably had a similar lifestyle as an ambush aquatic predator feeding on fish and other aquatic animals. A study on the closely related "Archegosaurus" shows that it had a heat balance, gas exchange, osmoregulation, and digestion more similar to that of fish than modern aquatic amphibians; the same probably applied to "Prionosuchus" as well.
Prionosuchus | Description