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''Europasaurus'' is a basal macronarian
sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their ...
, a form of
quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuo ...
al
herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23  million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
. It lived during the Late
Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
(middle
Kimmeridgian In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 157.3 ± 1.0 Ma and 152.1 ± 0.9 Ma (million years ago). The Kimmeridgian follows the Oxford ...
, about 154 million years ago) of northern
Germany Germany, officially the Federal Republic of Germany (FRG),, is a country in Central Europe. It is the most populous member state of the European Union. Germany lies between the Baltic and North Sea to the north and the Alps to the sou ...
, and has been identified as an example of
insular dwarfism Insular dwarfism, a form of phyletic dwarfism, is the process and condition of large animals evolving or having a reduced body size when their population's range is limited to a small environment, primarily islands. This natural process is dist ...
resulting from the isolation of a sauropod population on an island within the Lower Saxony basin.


Discovery and naming

In 1998, a single sauropod tooth was discovered by private fossil collector Holger Lüdtke in an active quarry at Langenberg Mountain, between the communities of Oker, Harlingerode and Göttingerode in Germany. The
Langenberg chalk quarry Langenberg can refer to: People *Arend Langenberg (1949-2012), Dutch voice actor and radio presenter * Donald N. Langenberg (1932-2019), American physicist *James Van Langenberg, 5th Solicitor General of Ceylon *Silke Langenberg (born 1974) is a G ...
had been active for more than a century; rocks are quarried using blasting and are mostly processed into fertilisers. The quarry exposes a nearly continuous, thick succession of
carbonate rock Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3), and dolomite rock (also known as doloston ...
s belonging to the Süntel Formation, that ranges in age from the early Oxfordian to late
Kimmeridgian In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 157.3 ± 1.0 Ma and 152.1 ± 0.9 Ma (million years ago). The Kimmeridgian follows the Oxford ...
stages and have been deposited in a shallow sea with a water depth of less than . The layers exposed in the quarry are oriented nearly vertically and slightly overturned, which is a result of the ascent of the adjacent
Harz mountains The Harz () is a highland area in northern Germany. It has the highest elevations for that region, and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt, and Thuringia. The name ''Harz'' derives from the Middle High German w ...
during the
Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Gloucestershire, England See also *Nizhny Nizhny (russian: Ни́жний; masculine), Nizhnyaya (; feminine), or Nizhneye (russian: Ни́� ...
. Widely known as a classical exposure among geologists, the quarry had been extensively studied, and visited by students of geology for decades. Although rich in fossils of marine invertebrates, fossils of land-living animals had been rare. The sauropod tooth was the first specimen of a sauropod dinosaur from the Jurassic of northern Germany. After more fossil material was found, including bones, excavation of the bone-bearing layer commenced in April 1999, conducted by a local association of private fossil collectors. Although the quarry operator was cooperative, excavation was complicated by the near-vertical orientation of the layers that limited access, as well as by the ongoing quarrying. The sauropod material could not be excavated directly from the layer but had to be collected from lose blocks that resulting from blasting. The exact origin of the bone material was therefore unclear, but could later be traced to a single bed (bed 83). An excavation conducted between July 20–28 of 2000 rescued ca. of bone-bearing blocks containing vertebrate remains. Fossils were prepared and stored in the Dinosaur Park Münchehagen (DFMMh), a private dinosaur open-air museum located close to
Hanover Hanover (; german: Hannover ; nds, Hannober) is the capital and largest city of the German state of Lower Saxony. Its 535,932 (2021) inhabitants make it the 13th-largest city in Germany as well as the fourth-largest city in Northern Germany ...
. Due to the very good preservation of the bones, consolidating agents had to be applied only occasionally, and preparation could be conducted comparatively quickly as bone would separate easily from the surrounding rock. Bones of simple shape could sometimes be prepared in less than an hour, while the preparation of a
sacrum The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part ...
required a workload of three weeks. By January 2001, 200 single vertebrate bones had already been prepared. At this point, the highest bone density was found in a block measuring 70 x 70 cm, which contained ca. 20 bones. By January 2002, preparation of an even larger block had revealed a partial sauropod skull – the first to be discovered in Europe. Before complete removal of the bones from the block, a silicon cast was made of the block to document the precise three-dimensional position of the individual bones. Part of the ''Europasaurus'' fossil material got damaged or destroyed by arson fire in the night from the 4th to the 5th of October, 2003. The fire destroyed the laboratory and exhibition hall of the Dinosaur Park Münchehagen, resulting in the loss of 106 bones, which account for 15% of the bones prepared at the time. Furthermore, the fire affected most of the still unprepared blocks, with firefighting water hitting the hot stone causing additional crumbling. Destroyed specimens include DFMMh/FV 100, which included the best preserved vertebral series and the only complete pelvis. In 2006, the new sauropod
taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...
was formally described as ''Europasaurus holgeri''. The given
etymology Etymology () The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the form of words ...
for the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...
name is "reptile from Europe", and the specific name honours Holger Lüdtke, the discoverer of the first fossils. Given the comparatively small size of the bones, it was initially assumed that they stem from juvenile individuals. The 2006 publication, however, established that the majority of specimens were adult, and that ''Europasaurus'' was an island dwarf. The number of individual sauropod bones had increased to 650 and include variously articulated individuals; the material was found within an area of squared. From these specimens, the
holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...
was selected, a disarticulated but associated individual (DFMMh/FV 291). The holotype includes multiple cranial bones (
premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...
,
maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The ...
and quadratojugal), a partial braincase, multiple
mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bon ...
bones (
dentary In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
,
surangular The suprangular or surangular is a jaw bone found in most land vertebrates, except mammals. Usually in the back of the jaw, on the upper edge, it is connected to all other jaw bones: dentary, angular, splenial and articular The articular bone ...
and angular), large amounts of teeth,
cervical vertebrae In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In ...
, sacral vertebrae and
ribs The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels. The sternum, together known as the thoracic cage, is a semi ...
from the neck and torso. At least 10 other individuals were referred to the same taxon based on overlap in material. A large-scale excavation campaign commenced in the summer of 2012, with the goal to excavate ''Europasaurus'' bones not only from lose blocks but directly from the rock layer. Access to the bone-bearing layer required the removal of some 600 tons of rock using excavators and wheel loaders, and the constant pumping out of water from the base of the quarry. Excavations continued in spring and summer 2013. The campaign resulted in the discovery of new fish, turtle, and crocodile remains, as well as valuable information of the bone-bearing layer; additional ''Europasaurus'' bones, however, could not be located. By 2014, around 1300 vertebrate bones had been prepared from bed 83, the majority of which stemming from ''Europasaurus''; an estimated 3000 additional bones await preparation. A minimum number of 20 individuals was identified based on jaw bones.


Description

''Europasaurus'' is a very small sauropod, measuring only as an adult. This length was estimated based on a partial femur, scaled to the size of a nearly complete ''
Camarasaurus ''Camarasaurus'' ( ) was a genus of quadrupedal, herbivorous dinosaurs and is the most common North American sauropod fossil. Its fossil remains have been found in the Morrison Formation, dating to the Late Jurassic epoch (Kimmeridgian to Titho ...
'' specimen. Younger individuals are known, from sizes of to the youngest juvenile at . Gregory S. Paul estimated that a long individual would have weighed .


Distinguishing characteristics

Aside from being a very small neosauropod, ''Europasaurus'' was thought to have multiple unique morphological features to distinguish it from close relatives by its original describers, Sander ''et al.'' (2006). The nasal process of the premaxilla was thought to curve anteriorly while projecting upwards (now known to be preservational), there is a notch on the upper surface of the centra of cervical vertebrae, the
scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eithe ...
has a prominent process on the posterior surface of its body, and the
astragalus ''Astragalus'' is a large genus of over 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae and the subfamily Faboideae. It is the largest genus of plants in terms of described species. The genus is native to te ...
(an ankle bone) is twice as wide as tall. When compared to ''Camarasaurus'', ''Europasaurus'' has a different morphology of the
postorbital The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some v ...
where the posterior flange is not as short, a short contact between the
nasal Nasal is an adjective referring to the nose, part of human or animal anatomy. It may also be shorthand for the following uses in combination: * With reference to the human nose: ** Nasal administration, a method of pharmaceutical drug delivery ** ...
and
frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, pa ...
s of the skull, the shape of its parietal (rectangular in ''Europasaurus''), and the
neural spine The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...
s of its vertebrae in front of the pelvis are unsplit. Comparisons with ''
Brachiosaurus ''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about 154to 150million years ago. It was first described by American paleontologist Elmer S. Riggs in 1903 from fossils found in the ...
'' (now named ''
Giraffatitan ''Giraffatitan'' (name meaning "titanic giraffe") is a genus of sauropod dinosaur that lived during the late Jurassic Period (Kimmeridgian–Tithonian stages) in what is now Lindi Region, Tanzania. It was originally named as an African species ...
'') were also mentioned, and it was identified that ''Europasaurus'' has a shorter snout, a contact between the quadratojugal and
squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestral co ...
, and a
humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...
(upper forelimb bone) that has flattened and aligned
proximal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position ...
and
distal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
surfaces. There were finally quick comparisons to the potential brachiosaurid ''
Lusotitan ''Lusotitan'' is a genus of herbivorous brachiosaurid sauropod dinosaur from the Late Jurassic Period of Portugal. Discovery and naming In 1947 Manuel de Matos, a member of the Geological Survey of Portugal, discovered large sauropod fossils ...
'', which has a different
ilium Ilium or Ileum may refer to: Places and jurisdictions * Ilion (Asia Minor), former name of Troy * Ilium (Epirus), an ancient city in Epirus, Greece * Ilium, ancient name of Cestria (Epirus), an ancient city in Epirus, Greece * Ilium Building, a ...
and astragalus shape, and ''
Cetiosaurus humerocristatus ''Duriatitan'' is a genus of titanosauriform sauropod dinosaur that lived in the Late Jurassic in what is now England. The holotype specimen of ''Duriatitan'', BMNH 44635, is a partial left upper arm bone which was found by R.I. Smith nea ...
'' (named ''
Duriatitan ''Duriatitan'' is a genus of titanosauriform sauropod dinosaur that lived in the Late Jurassic in what is now England. The holotype specimen of ''Duriatitan'', BMNH 44635, is a partial left upper arm bone which was found by R.I. Smith near ...
''), which has a deltopectoral crest that is less prominent and extends across less of the humerus.


Skull

Nearly all external skull bones have been preserved among ''Europasaurus'' specimens, except the prefrontals. Some additional bones are only represented by very fragmented and uninformative fossils, such as the
lacrimals The lacrimal bone is a small and fragile bone of the facial skeleton; it is roughly the size of the little fingernail. It is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders. Several bony landmarks of ...
. Eight premaxillae are known, with a generally rectangular snout shape as found in ''Camarasaurus''. The anterior projection of the premaxilla identified in Sander ''et al.'' (2006) was re-identified as a preservational artifact in Marpmann ''et al.'' (2014), similar to the anatomy found in ''Camarasaurus'' and '' Euhelopus'' to a lesser degree. The
dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...
projection of the premaxilla, the one which contacts the nasal bone, begins as a postero-dorsal projection, before becoming straight vertical at the point of the subnarial
foramen In anatomy and osteology, a foramen (;Entry "foramen"
in
, until it reaches the nasal. This weak "step" is seen in ''Camarasaurus'' and ''Euhelopus'', and is present more strongly in ''
Abydosaurus ''Abydosaurus'' (meaning " Abydos lizard") is a genus of brachiosaurid sauropod dinosaur known from skull and postcranial material found in upper Lower Cretaceous rocks of northeastern Utah, United States. Discovery ''Abydosaurus'' is one of th ...
'', ''Giraffatitan'' and a possible skull of ''Brachiosaurus''. These latter taxa also have a longer snout, with more distance from the first tooth until the nasal process of the premaxilla. As well, ''Europasaurus'' shares with the basal camarasauromorphs (brachiosaurids, ''Camarasaurus'', ''Euhelopus'' and ''
Malawisaurus ''Malawisaurus'' (meaning "Malawi lizard") is an extinct genus of titanosaurian sauropod dinosaur. It is known from the Dinosaur Beds of northern Malawi, which probably date to the Aptian stage of the Early Cretaceous. The type species is ''M. ...
'') a similarly sized
orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such a ...
and
nasal fenestra The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...
, whereas the nasal opening is significantly reduced in derived titanosaurs ('' Rapetosaurus'', ''
Tapuiasaurus ''Tapuiasaurus'' (meaning " Tapuia lizard") is a genus of titanosaur which lived during the Lower Cretaceous period (Aptian age) in what is now Minas Gerais, Brazil. Its fossils, including a partial skeleton with a nearly complete skull, h ...
'' and ''
Nemegtosaurus ''Nemegtosaurus'' (meaning 'Reptile from the Nemegt') was a sauropod dinosaur from the Late Cretaceous Period of what is now Mongolia. It was named after the Nemegt Basin in the Gobi Desert, where the remains — a single skull — were found. T ...
''). A single maxilla is present in the well-preserved material of ''Europasaurus'', DFMMh/FV 291.17. This maxilla has a long body, with two elongate processes, a nasal and a posterior process. There is only a weak lacrimal process, like in most sauropods except ''Rapetosaurus''. The nasal process is elongate and covers the anterior and ventral rim of the
antorbital fenestra An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with archosauriforms, first appearing during the Triassic Period. Among extant archosaurs, birds ...
. This process extends about 120º from the horizontal
tooth row Sharks continually shed their teeth; some Carcharhiniformes shed approximately 35,000 teeth in a lifetime, replacing those that fall out. There are four basic types of shark teeth: dense flattened, needle-like, pointed lower with triangular ...
. The base of the nasal process also forms the body of the lacrimal process, and at their divergence is the antorbital fenestra, similar in shape to those of ''Camarasaurus'', ''Euhelopus'', ''Abydosaurus'' and ''Giraffatitan'', but about 1/2 taller proportionally. The pre-antorbital fenestra, a small opening in front of or beneath the antorbital opening, is well developed in taxa like ''
Diplodocus ''Diplodocus'' (, , or ) was a genus of diplodocid sauropod dinosaurs, whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a neo-Latin term derived from Greek διπ� ...
'' and ''Tapuiasaurus'', is nearly absent, like in ''Camarasaurus'' and ''Euhelopus''. There were about 12–13 total teeth in the maxilla of ''Europasaurus'', fewer than in more basal taxa (16 teeth in ''
Jobaria ''Jobaria'' is a genus of sauropod dinosaur that lived in what is now Niger during the middle Jurassic Period, between 164 and 161 million years ago. ''Jobaria'' is currently the only known valid sauropod from the Tiouraren, where it was discove ...
'' and 14–25 in '' Atlasaurus''), but falling within the range of variation in Brachiosauridae (15 in ''Brachiosaurus'' to 10 in ''Abydosaurus''). All of the unworn teeth preserved display up to four small denticles on their mesial edges. A small amount of the posterior tooth crowns are slightly twisted (~15º), but much less than in brachiosaurids (30–45º). Among the nasal bones of ''Europasaurus'', several are known, but few are complete or undistorted. The nasals are overlapped posteriorly by the frontal bones, and towards the side, they articulate bluntly with the prefrontals. Unlike the nasals of ''Giraffatitan'', those in ''Europasaurus'' project horizontally forwards, forming a small portion of the skull roof over the antorbital fenestrae. Four frontals are known from ''Europasaurus'', three being from the left and one being from the right. Because of their disarticulation, it is likely that the frontals never fused during growth, unlike in ''Camarasaurus''. The frontals form a portion of the skull roof, articulating with other bones such as the nasals, parietals, prefrontals and postorbitals, and they are longer antero-posteriorly than they are wide, a unique character among a
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 ...
n. Like in diplodocoids ('' Amargasaurus'', '' Dicraeosaurus'' and ''Diplodocus''), as well as ''Camarasaurus'', the frontals are excluded from the frontoparietal fenestra (or parietal fenestra when frontals are excluded). The frontals are also excluded from the supratemporal fenestra margin (a widespread character in sauropods more derived than '' Shunosaurus''), and they only have a small, unornamented participation in the
orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such a ...
. Several parietal bones are known in ''Europasaurus'', which show a rectangular shape much wider than long. the parietals are also wide when viewed from the back of the skull, being slightly taller than the
foramen magnum The foramen magnum ( la, great hole) is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblonga ...
(spinal cord opening). The parietals contribute to about half the post-temporal fenestra (opening above the very back of the skull) border, with the other region enclosed by the squamosal bones and some braincase bones. Parietals also form part of the edge of the supratemporal fenestra, which is wider than long in ''Europasaurus'', like in ''Giraffatitan'', ''Camarasaurus'' and '' Spinophorosaurus''. Besides the before mentioned fenestra, the parietals also have a "postparietal fenestra", something rarely seen outside of Dicraeosauridae. A triradiate postorbital bone is present in ''Europasaurus'', which evolved as the fusion of the postfrontal and postosbital bone of more basal taxa. Between the anterior and ventrally projecting processes the postorbital forms the margin of the orbit, and between the posterior and ventral processes it borders the infratemporal fenestra. Multiple jugals are known from ''Europasaurus'', which are more similar in morphology to basal sauropodomorphs than other macronarians. It forms part of the border of the orbit, infratemporal fenestra and the bottom edge of the skull, but does not reach the antorbital fenestra. The posterior process of the jugal are very fragile and narrow, showing a bone scar from the articulation with the quadratojugal. There are two prominences projecting from the back of the jugal body, which diverge at 75º and form the bottom and front edges of the infratemporal fenestra. Like in ''
Riojasaurus ''Riojasaurus'' (meaning "Rioja lizard") was a herbivorous sauropodomorph dinosaur named after La Rioja Province in Argentina where it was found in the Los Colorados Formation in the Ischigualasto-Villa Unión Basin by José Bonaparte. It lived ...
'' and '' Massospondylus'', two non-sauropod sauropodomorphs, the jugal forms a large part of the orbit edge, from the back to the front bottom corner. This feature has been seen in
embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that