Sauropodomorpha
Sauropodomorpha is composed of the
sauropods and their basal relatives, known informally as prosauropods, a broad
group of in general unaccountably poorly-known early quadrupedal long-necked
herbivores. Because I believe a "prosauropod" was the ancestor of the sauropods, I do not consider Prosauropoda to be a
natural, monophyletic (including all descendants) group, and reserve the term as an
informal name for this assortment of MTr-EJ dinosaurs that aren't sauropods but aren't
members of another dinosaur group either. A certain subset may well form a
small Prosauropoda, though.
Again, prosauropods are probably the
least-understood dinosaurs (although this is shifting to the basal ornithopods). Part of this stems from the fact that all known prosauropods
are older than about 180 million years, reducing the completeness of their record, and
part of this stems from the fact that prosauropods are a unique taxonomic quagmire.
While there are certain dinosaurs (Megalosaurus, Iguanodon, Trachodon)
that have become black holes, no other section of dinosaurs as a whole has gone through so
much screwiness. Plateosaurus, for example, has over a dozen
possible synonyms, Massospondylus
carinatus eleven, Euskelosaurus another half-dozen, and Anchisaurus
has
gone through three different generic names. On the flip side, Thecodontosaurus
has hosted at least thirteen species. Some of the better known taxa are known from
over twenty partial specimens, though.
Aside from their general appearance
(long neck, small head, bipedal to somewhat quadrupedal), they are best known for their wicked
thumb claws, probably powerful defensive tools. They were once thought to be carnivores, due mostly to mixing of shed
theropod teeth with prosauropod remains, but this has been show to be false,
although some could have been omnivorous, as suggested by animal remains within the
skeleton of one find.
Our knowledge of basal sauropodomorphs is currently going
through a major revision, particularly as it relates to the taxonomy of animals
from the late Triassic of Europe and South Africa, and to the ancestry of
sauropods and if there is anything that would make a Prosauropoda besides Plateosaurus
and a few of its best friends. At some point, Prosauropod Pinball will
settle down, but until then, don't get too attached to anything here.
(Really, basal dinosaurs as a whole are very unsettled right now, but this is
where all the published fun is at the moment.)
Here is the latest revision of Sauropodomorpha, now with no
meaningful Prosauropoda. Massopoda is all sauropodomorphs closer to Saltasaurus
than Plateosaurus. Sauropoda
covers everyone past Melanorosaurus, so it's just like how it was when it
was, except completely different.
<--Sauropodomorpha
|--Guaibasauridae
| |--Agnosphitys
| |--Guaibasaurus
| |--Panphagia
| `--Saturnalinae
| |--Chromogisaurus
| `-- Saturnalia
`--+--Pantydraco
|--Thecodontosaurus
`--+--Nambalia
`--+--Efraasia
`--+--Plateosauravus
`--+--Ruehleia
`--+--Plateosauridae
| |--Jaklapallisaurus
| |--Plateosaurus
| `--Unaysaurus
`--Massopoda
|--Riojasauridae
| |--Eucnemesaurus
| `--Riojasaurus
`--+--Gryponyx
|--Ignavusaurus
|--Saharsaurus
|--Massospondylidae
| |--+--Massospondylus
| |
`--+--Adeopapposaurus
| | `--Leyesaurus
| `--+--Coloradisaurus
| |--Glacialisaurus
| `--Lufengosaurus
`--+--Jingshanosaurus
`--+--Yunnanosaurus
`--+--Seitaad
`--Anchisauria
|--Anchisaurus
`--+--Aardonyx
`--+--Leonerasaurus
`--+--Melanorosaurus
`-->Sauropoda
Guaibasauridae: These taxa were generally described as basal saurischians of one
stripe or another. Guaibasaurus in particular was all over the map
in and out of Theropoda and Sauropodomorpha. Of course, this area is subject to
change; you may prefer to consider these as a clutch of saurischians at the base
of Theropoda and Sauropodomorpha.
| Taxon or Taxa: | Time/Place: | Comments: |
| Agnosphitys cromhallensis Fraser, Padian, Walkden, and Davis, 2002 | ?Norian-Rhaetian (LTr) of England | A possible basal dinosaur, described as more derived than Eoraptor and Herrerasaurus (but interestingly, in the description all are considered basal to true dinosaurs), it is based on an ilium (with partially-perforated acetabulum and two sacrals), with maxilla, astragalus, humerus, and teeth referred to it. It has been misspelled as Agnostiphys and Agnosphytis in the past. The remains could be chimeric, with the maxilla being theropodan. |
| Chromogisaurus novasi Ezcurra, 2010 | late Carnian (LTr) of Argentina | Chromogisaurus is known mostly from a pelvis and partial hindlimbs. |
| Guaibasaurus candelariai Bonaparte, Ferigolo, and Ribeiro, 1999 | earliest Norian (LTr) of Brazil | This dinosaur has jumped around the basal stems of the great dinosaurian lineages. Currently a sauropodomorph, it has also been considered to be somewhere around Staurikosaurus and the rest of Herrerasauridae and/or basal to the Theropoda/Sauropodomorpha split. Remains of several individuals are known, including one partial articulated skeleton representing most of the body posterior to the neck; unfortunately, the skull remains unknown. The acetabulum shows little opening, but the fifth toe is reduced, with no phalanges. |
| Panphagia protos Martínez and Alcober 2009 | late Carnian (LTr) of Argentina | Panphagia pushes back the sauropodomorph family tree a little farther, to a time when they looked a bit like Dino of Flintstones fame with an Eoraptor's head. The teeth at the front of the jaws were quite long and pointed, becoming less offensive farther down the line. Most of the skeleton is known, with the exception of the arms and most of the legs. The name Panphagia, as those of you who can at least fake your way through the translation know (or who have the article, of course), is a reference to its proposed omnivorous habits. |
| Saturnalia tupiniquim Langer, Abdula, Richter, and Benton, 1999 | ?earliest Norian (LTr) of Brazil | This animal was classified as the most basal sauropodomorph known when first described. It is based on three partial skeletons representing most of the body, and is roughly a contemporary of the Ischigualasto (i.e. Herrerasaurus) fauna. At about a meter and a half long, it was a small prosauropod. Material from Zimbabwe may be referable. |
Guaibasaurid-grade sauropodomorph-things, i.s.:
| Taxon or Taxa: | Time/Place: | Comments: |
| Pampadromaeus barberenai Cabreira, Schultz, Bittencourt, Soares, Fortier, Silva, and Langer, 2011 | late Carnian (LTr) of Brazil | Pampadromaeus is a basal saurischian leaning to the sauropodomorph side of things. It is known from a partial disarticulated skeleton that includes most of the torso and limbs, part of the tail, and a partial skull and lower jaw. It is big-headed, as these basal sauropodomorph-ish animals go, and the tip of the snout is expanded ventrally, giving it hanging (and bitey-looking) premaxillae. |
Sauropodomorpha after Guaibasauridae: With the demolition of Prosauropoda as a separate group, the following animals cover a wide range of sizes, times, places, and probably habits. The basalmost animals here are generally grouped as "thecodontosaurs". They were the smallest and most basal of the sauropodomorphs.
| Taxon or Taxa: | Time/Place: | Comments: |
| Pantydraco caducus Galton, Yates, and Kermack, 2007 (originally Thecodontosaurus caducus Yates, 2003) | Norian-Rhaetian (LTr) of Wales | Its remains known since 1952, and occasionally illustrated (especially the skull), Pantydraco is based on a good portion of the front end of one juvenile individual, plus miscellaneous other remains. Its remains provided the modern image of Thecodontosaurus. The skull is rather like Eoraptor in gross characteristics. The name comes from Pant-y-ffynnon, referring to the quarry where the bones were discovered. |
| Thecodontosaurus antiquus (genus after Riley and Stutchbury, 1836, species after Morris, 1843) | Norian-Rhaetian (LTr) of England | Thecodontosaurus had long been the most primitive
sauropodomorph for which we have good remains, comprising at least 13
individuals. It was also a long-time wastebasket,
but most of the cobwebs have been cleared away. It was once thought
that the majority of the remains were
destroyed in WWII, but it was recently discovered that some had been saved in other
institutions, and restudy is underway. It may have been dimorphic. Agrosaurus macgillivrayi Seeley, 1891 was once thought to be the only known Australian LTr dinosaur. However, it turned out that the material it was based on was mislabeled, actually from England, and belonged to Thecodontosaurus. |
| Nambalia roychowdhurii Novas, Ezcurra, Chatterjee, and Kutty, 2011 | late Norian-earliest Rhaetian (LTr) of India | This basal sauropodomorph is based on a right ilium and most of a left leg (minus the foot). Partial postcrania from two other individuals have been referred to it as well, adding hand, foot, caudal, and additional pelvic bones to the picture. |
| Efraasia minor (Huene, 1907-08 [originally Teratosaurus]) | mid Norian (LTr) of Germany | Efraasia has been resurrected after being considered a juvenile Sellosaurus during the 1980s and '90s. It is somewhat more basal than Plateosaurus (to which Sellosaurus has been referred), and is moderately sized (up to 6 m long; it used to be considered a small dinosaur because the best remains were juvenile). |
| Plateosauravus cullingworthi Huene, 1932 (species after Haughton, 1924 [originally Plateosaurus]) | early Norian (LTr) of South Africa | This is what should be used for the majority of the "Euskelosaurus" material. It was a large but gracile basal sauropodomorph, and is known from partial skeletons. It was once thought to be the same as Melanorosaurus, but this was disproved based on the femora of the two: Plateosauravus (Euskelosaurus) has a femur which is bent in rear view, while that of Melanorosaurus is straight. Its braincase may have been unusually primitive. Juvenile material is apparently known as well. |
| Ruehleia bedheimensis Galton, 2001 | late Norian (LTr) of Germany | Ruehleia is a new basal sauropodomorph, originally referred to Plateosaurus plieningeri, based on much of a skeleton (excepting most importantly the skull and hind feet). Another specimen is referred. The type was originally wall-mounted in the same castle as Liliensternus. It was a good-sized prosauropod, in the 8 meter long range. |
Sauropodomorpha i.s., the "somewhat better known taxa" division: There are literally dozens of taxa based on cruddy remains (we're not just talking single bones, here, necessarily; we could be talking parts of single bones) that have been in the past synonymized with Euskelosaurus, Plateosaurus, and Massospondylus, but which are not currently regarded as such, mostly because they're too cruddy to be sure. They are to be found in the table following this one, which holds the sauropodomorphs of uncertain position that are well-defined. Membership of both tables is subject to change.
| Taxon or Taxa: | Time/Place: | Comments: |
| Arcusaurus pereirabdalorum Yates, Bonnan, and Neveling, 2011 | ?Pliensbachian (EJ) of South Africa | Arcusaurus is known from a partial juvenile skull, with some assorted cranial and postcranial remains from the same site referred to it. It appears to have been similar to Thecodontosaurus and its ilk, and may be a late-surviving representative of the very basal stripe of sauropodomorphs, with the caveat that it is known only from juvenile remains. |
| Asylosaurus yalensis Galton, 2007 | Rhaetian (LTr) of England | Asylosaurus was named for the Thecodontosaurus material that was protected from WWII bombing by being at Yale, having been brought there by O.C. Marsh several decades before. It has a distinctive upper arm. |
| Chuxiongosaurus lufengensis Lü J., Kobayashi, Li T., and Zhong S., 2010 | EJ of China | Chuxiongosaurus is based on a nearly complete skull, and is described as a sauropod more basal than Anchisaurus. Given the ongoing difficulties of sauropodomorph classification, it is not feasible to do much more with this genus without the paper in hand (and probably not much more feasible with it!). |
| Euskelosaurus browni (N.D.) Huxley, 1866 | early Norian (LTr) of Lesotho, South Africa, and ?Zimbabwe | This sauropodomorph is relatively famous as a token prosauropod in detailed kids' books, but is based on dubious material. The good material has been referred to a variety of other things, including Plateosauravus cullingworthi, Eucnemesaurus fortis, and the remains now known as the type of Antetonitrus ingenipes. |
| "Gyposaurus" sinensis Yang, 1941 (?Lufengosaurus) | Hettangian-Sinemurian (EJ) of China | Usually tossed off as a juvenile of Lufengosaurus (or as another species of Anchisaurus; there was a period of time in the '80s when Gyposaurus species found their way into the clutches of the sneaky beast, but then ended up being referred elsewhere), "Gyposaurus" sinensis has been cropping up in cladograms lately, suggesting that something is afoot. It is based on partial remains from several individuals. |
| Lamplughsaura dharmaramensis Kutty, Chatterjee, Galton, and Upchurch, 2007 | Hettangian (EJ) of India | Lamplughsaura was a large basal sauropodomorph or basal sauropod (~10 m long), with a robust quadrupedal build. It is known from a nearly complete skeleton and the partial skeletons of four other individuals. One point of interest is that the thumb claw is not particularly curved, although still large. The skeletal restoration provided suggests an animal along the lines of Plateosaurus but with longish limbs, short caudal neural spines, and very long chevrons. |
| Mussaurus patagonicus Bonaparte and Vince, 1979 | Norian (LTr) of Argentina | Based on remains pertaining to very young animals, Mussaurus ("mouse reptile," in reference to the size of the specimens) was first thought to be a prosauropod of some sort, but new study indicates that it may not be (it has a non-prosauropod skull with forward-pointing teeth). The juveniles are supposedly linked through larger specimens to adult sauropodomorphs which are distinct from contemporary Coloradisaurus, but as yet have not been described. |
| Pradhania gracilis Kutty, Chatterjee, Galton, and Upchurch, 2007 | Sinemurian (EJ) of India | A smallish (~4 m long) basal sauropodomorph, Pradhania is known from a partial skull and hand and a few verts. It may be a massospondylid. |
| Xixiposaurus suni Sekiya, 2010 | Hettangian-Sinemurian (EJ) of China | Xixiposaurus is known from much of a skeleton including most of the skull, 20 presacral and 5 caudal vertebrae, portions of the pectoral girdle, most of the arms (minus the hands), and the right pelvis and leg. It was described as a very derived Chinese prosauropod. |
| Yimenosaurus youngi Bai vide Bai, Yang, and Wang, 1990 | EJ of China | Known from the remains of several individuals, Yimenosaurus has an unusually deep skull, like a basal sauropod's. Most of the skeleton except the arms and lower legs are known. |
Sauropodomorpha i.s., the "cruddy past synonyms of Euskelosaurus, Massospondylus, Plateosaurus, and Thecodontosaurus division," mostly: In general, you can guess what was the proposed synonym by the place and time. Euskelosaurus covers the late Triassic of South Africa, Massospondylus the early Jurassic of the same area, and Plateosaurus the late Triassic of Europe. If you wait a few years, a lot of them probably will be referred back to a better-known genus, but the dust still needs to settle. It'll get figured out eventually.
| Taxon or Taxa: | Time/Place: | Comments: | |
| Aetonyx palustris (N.D.) Broom, 1911 (?Massospondylus) | Hettangian (EJ) of South Africa | Aetonyx is based on most of an arm and two hands, some verts, part of a tibia, and most of a foot. | |
| Aristosaurus erectus Hoepen, 1920 (?Massospondylus) | Sinemurian (EJ) of South Africa | Aristosaurus is based on most of a skeleton of a juvenile missing the majority of the head and some portions of the forelimbs and scapulae. | |
| Dimodosaurus poligniensis (?N.D.) Pidancet and Chopard, 1862 | late Norian (LTr) of France | This is based on the hip region and hindlimb of a plateosaur-like animal. | |
| Dromicosaurus gracilis (?N.D.) Hoepen, 1920 (?Massospondylus) | Hettangian (EJ) of South Africa | Dromicosaurus is represented by a cervical, caudals, fragments of the humerus and radius, pubes, partial ischia, a femur, and part of a foot, from an animal in the large Massospondylus range. | |
| "Euskelosaurus" africanus (N.D.) Haughton, 1924 | early Norian (LTr) of South Africa | This is based on verts and a partial hip and hindlimb. | |
| Fulengia youngi (N.D.) Carroll and Galton, 1977 (?Lufengosaurus) | Sinemurian (EJ) of China | Originally described as a lizard, this is instead an indeterminate juvenile basal sauropodomorph, possibly the same as Lufengosaurus. | |
| Gigantoscelus molengraafi (N.D.) Hoepen, 1916 | Hettangian-Sinemurian (EJ) of South Africa | This is a dubious basal sauropodomorph based on a partial femur. | |
| Gresslyosaurus ingens (N.D.) Rütimeyer, 1856 | Rhaetian (LTr) of Switzerland | This longtime possible synonym of Plateosaurus is known from a partial sacrum, caudals, a metacarpal, and a partial hindlimb. | |
| "Gresslyosaurus" plieningeri (N.D.) Huene, 1907-08 | late Norian (LTr) of Germany | "G." plieningeri is based on a partial skeleton including a skull. | |
| "Gryponyx": | "G." taylori (N.D.) Haughton, 1924 | Hettangian (EJ) of South Africa | This is based on a pelvic girdle and sacrals. |
| "G." transvaalensis (N.D.) Broom, 1912 | Hettangian-Sinemurian (EJ) of South Africa | This is an indeterminate basal sauropodomorph based on a phalanx and partial metatarsal. | |
| Gyposaurus capensis (?N.D.) Broom, 1911 | Sinemurian (EJ) of South Africa | Gyposaurus (no, not Gryposaurus) is based on a partial skeleton from the shoulders to the beginning of the tail. It had been referred briefly to Anchisaurus during the early 1980s, at the tail end of the period just after the acceptance of plate tectonics when it was common to make intercontinental dinosaur connections (see Dryosaurus, Camptosaurus, and Iguanodon), although usually it has been stuck in Massospondylus. | |
| Hortalotarsus skirtopodus (N.D.) Seeley, 1894 | Hettangian-Sinemurian (EJ) of South Africa | Hortalotarsus has been mixed up with Gyposaurus, Anchisaurus, and Thecodontosaurus at various times in the past, when it seems to have garnered more attention than a partial tibia and foot should have had. For the most part recently, it has been put into Massospondylus. | |
| Leptospondylus capensis (N.D.) Owen, 1895 | Hettangian (EJ) of South Africa | You get two caudal centra. I'd say use them wisely, but they were blown up in WWII. | |
| "Lufengosaurus" magnus Yang, 1947 | Hettangian-Sinemurian (EJ) of China | "L." magnus is usually assumed to be a synonym of L. huenei, as based on large individuals. | |
| "Massospondylus": | "M." browni Seeley, 1895 | Hettangian-Sinemurian (EJ) of South Africa | This species, sometimes mixed up with Thecodontosaurus (unless T. browni had a different type, and I'm getting contradictory reports there), is based on limb material, verts, and pectoral\pelvic girdles, or two cervicals, two dorsals, three caudals, two femora, and a partial foot. |
| "M." harriesi (N.D.) Broom, 1911 | Hettangian (EJ) of South Africa | This is based on partial fore and hindlimbs (including a good hand and a foot). | |
| "M." hislopi (N.D.) Lydekker, 1890 | early Norian (LTr) of India | Unusual for its locality, this is an indeterminate basal sauropodomorph based on verts. | |
| "M." schwarzi (N.D.) Haughton, 1924 | Hettangian (EJ) of South Africa | This indeterminate basal sauropodomorph is based on a partial hindlimb and sacrum. | |
| "Melanorosaurus" thabanensis Gauffrey, 1993 | Hettangian (EJ) of Lesotho | Known from a femur, this species began as the youngest "melanorosaurid" known from good remains (some material assigned to the Chinese EJ Sinosaurus may also be "melanorosaurid"). However, doubt has been cast on its identity, and it may be a sauropod instead. | |
| Orosaurus capensis (N.D.) Huxley, 1867 (species name added by Lydekker, 1889 [originally Orinosaurus]) | early Norian (LTr) of South Africa | Another dubious basal sauropodomorph, based on a partial tibia, this is one of the many once tossed into Euskelosaurus. About the name: Huxley apparently left off a species name, which Lydekker supplied when he renamed it Orinosaurus on the mistaken belief that Orosaurus was preoccupied by Oreosaurus, a fossil animal associated with cream-centered chocolate wafer cookies (actually a lizard of some kind). | |
| "Pachysaurus": Huene, 1907-08/Fitzinger, 1843 (Pachysauriscus; ?Plateosaurus) | "P." ajax (N.D.) (type) Huene, 1907-08 | late Norian (LTr) of Germany | The species of "Pachysaurus" (also known as Pachysauriscus) are mute reminders of the impulse that seized researchers to name German sauropodomorphs at every opportunity. Three of them are based on partial postcranial skeletons that are probably just individuals of Plateosaurus, while "P." giganteus is represented by partial fibulae misidentified as metatarsals. |
| "P." giganteus (N.D.) Huene, 1932 | |||
| "P." magnus (N.D.) Huene, 1907-08 | |||
| "P." wetzelianus (N.D.) Huene, 1932 | |||
| Pachyspondylus orpenii (N.D.) Owen, 1854 | Hettangian (EJ) of South Africa | See Leptospondylus (except in this case we don't know what kind of verts they were before they were blown up). | |
| Pachysuchus imperfectus (N.D.) Yang, 1951 | Hettangian-Sinemurian (EJ) of China | Pachysuchus is known only from a fragment of the upper jaw. It was originally described as a phytosaur, a type of long-snouted reptile later shamelessly plagiarized by gharials and some other crocodilians. This assignment made it a curiosity, as there is otherwise very little evidence for phytosaurs persisting into the Early Jurassic. However, restudy indicates that the holotype actually came from a sauropodomorph. | |
| "Plateosaurus": (?Plateosaurus) | "P." erlenbergiensis (?N.D.) Huene, 1907-08 | late Norian (LTr) of Germany | Another possible species of Plateosaurus, this one is based on a partial skull, girdles, and limbs. |
| "P." reiningeri (N.D.) Huene, 1907-08 | late Norian (LTr) of Germany | This basal sauropodomorph may be the same as Plateosaurus, but is too poorly known to be certain. It is based on most of a skeleton. | |
| "P." stormbergensis (N.D.) Broom, 1915 | early Norian (LTr) of South Africa | Based on a femur, metacarpal, pubis, and verts, this animal was once referred to Euskelosaurus. | |
| Tawasaurus minor (N.D.) Yang, 1982 (?Lufengosaurus) | Sinemurian (EJ) of China | This indeterminate basal sauropodomorph may be a juvenile Lufengosaurus. | |
| "Teratosaurus" trossingensis (N.D.) Huene 1907-08 | mid Norian (LTr) of Germany | This is a dubious basal sauropodomorph once referred to Sellosaurus based on a tail and hindlimbs. | |
| "Thecodontosaurus": | "T." dubius (?N.D.) Haughton, 1924 | Sinemurian (EJ) of South Africa | "T." dubius is based on most of a skeleton, so it may in fact not be dubious. |
| "T." minor (N.D.) Haughton, 1918 | early Norian (LTr) of S. Africa | This small indeterminate basal sauropodomorph, based on a tibia, cervical, and ischium, may be a late "thecodontosaur." | |
| "T." hermannianus (N.D.) Huene, 1907-08 | mid Norian (LTr) of Germany | Based on a partial maxilla, this animal is clearly a basal sauropodomorph of some type, but the material is too poor to define it any farther. | |
| "Thotobolosaurus mabeatae" (N.N.) Ellenberger, 1970 | ?early Norian (LTr) of Lesotho | This undescribed basal sauropodomorph may be a melanorosaurid. | |
| "Yunnanosaurus": | "Y." robustus Yang, 1951 | Hettangian-Sinemurian (EJ) of China | Known from a large partial skeleton and skull, "Y." robustus is here under the typical quarantine used for species with a genus needing restudy. |
| "Y." youngi Lü J., Li T., Zhong S., Azuma, Fujita, Dong Z., and Ji Q., 2007 | MJ of China | "Y." youngi is based on a vertebral column and pelvis, and has the honor of being the latest-known "prosauropod," as well as among the largest. | |
| "Zanclodon": | "Z." bavaricus (N.D.) Fraas, 1894 | late Norian (LTr) of Germany | This is a basal sauropodomorph based on 2 verts and the distal end of a tibia. It could be the same as Plateosaurus. |
| "Z. quenstadti" (N.N.) Huene, 1905 | late Norian (LTr) of Germany | This basal sauropodomorph is based on cervicals, dorsals, a sacrum, pelvic material, and most of the limbs. Like a lot of the animals here, it could be the same as Plateosaurus. | |
| Taxon or Taxa: | Time/Place: | Comments: | |
| Jaklapallisaurus asymmetrica Novas, Ezcurra, Chatterjee, and Kutty, 2011 | Jaklapallisaurus is a small plateosaurid known from a couple of vertebrae and most of the right leg. | ||
| Plateosaurus: Meyer, 1837 (including Sellosaurus Huene, 1907-08) | P. engelhardti (type) Meyer, 1837 | mid Norian-?Rhaetian (LTr) of Germany, Greenland, France, Sweden, and Switzerland | One of the most common and best known dinosaurs, Plateosaurus wasn't always so well-known. For many years its remains were scattered among a long list of prosauropods long forgotten, the most prominent being Gresslyosaurus Rütimeyer (1856). However, studies in the last thirty years have brought this taxon back. It is now generally known as a prototypical prosauropod, with over 100 partial to complete skeletons and ten skulls known for it. However, new research points to the necessity of reorganizing the known material. Galton has presented the argument that P. longiceps represents the famous Trossingen plateosaur, although researchers in Germany dispute this. |
| P. gracilis (Huene, 1907-08 [originally Sellosaurus]) | mid Norian (LTr) of Germany | "Sellosaurus" apparently actually consists of two distinct taxa, one a more basal sauropodomorph which should be called Efraasia minor, the other a medium-sized (4-6 m long) species of Plateosaurus. | |
| Unaysaurus tolentinoi Leal, Azevedo, Kellner, and Da Rosa, 2004 | Norian (LTr) of Brazil | Unaysaurus is based on a partial skeleton recovered in 1998 from a road construction site. The skeleton is partially articulated and includes a skull, lower jaw, and partial postcranium. It is described as bipedal, around 2.5 meters long, and possibly close to Plateosaurus. | |
Massopoda:
| Taxon or Taxa: | Time/Place: | Comments: |
| Gryponyx africanus Broom, 1911 (?Massospondylus) | Hettangian (EJ) of South Africa | Gryponyx is based on verts, both hands, a pelvis, and hindlimbs. |
| Ignavusaurus rachelis Knoll, 2010 (?Massospondylus) | ?Hettangian (EJ) of Lesotho | Ignavusaurus is known from a partial articulated skeleton from an individual perhaps less than a year old, with the torso, anterior tail, and hindlimb well-represented, the shoulders largely absent, and the skull present but very fragmented. It may represent a specimen of one of the two Massospondylus species. |
| Sarahsaurus aurifontanalis Rowe, Sues, and Reisz, 2010 | Sinemurian-mid Pliensbachian (EJ) of Arizona | You may remember Sarahsaurus as the Arizona Massospondylus (when all else fails with prosauropods, always compare to Massospondylus). There's quite a bit more known for this animal than the skull that occasionally surfaced in the years before description: the type is most of the skeleton, and there are significant chunks of two other individuals. Interestingly, it shows up as a quite basal sauropodomorph, a basal sauropod, or in between, depending on the phylogenetic matrix used. Given the quality of material, this probably speaks more to our incomplete knowledge of our prosauropod friends. The results also show the three named diagnostic North American basal sauropodomorphs (Anchisaurus, Sarahsaurus, and Seitaad) in distinct, well-separated positions, indicating that this wasn't a local radiation of closely related forms. |
| Jingshanosaurus xinwaensis Zhang and Yang, 1995 | Hettangian-Pliensbachian (EJ) of China | Jingshanosaurus may be a sauropodomorph or a basal sauropod. For an early dinosaur, it was good-sized, upwards of thirty feet long. Its describers suggested it might have been an omnivore, consuming mollusks and fish as well as plants. |
| Yunnanosaurus huangi Yang, 1942 | Hettangian-Sinemurian (EJ) of China | Yunnanosaurus is a prosauropod based on good remains (over twenty partial skeletons and two skulls have been referred to it), yet is unaccountably obscure. Some researchers have suggested that its referred sauropod-like teeth, that closely resemble those of the macronarian sauropods Brachiosaurus and Pleurocoelus instead of the normal, leaflike teeth of most prosauropods, actually belong to an early sauropod. There may be another "yunnanosaurid" in the Norian (LTr) of France. |
| Seitaad ruessi Sertich and Loewen, 2010 | ?Pliensbachian (EJ) of Utah | As of 2010, there have been three published sauropodomorphs from the Navajo Sandstone: the two from Arizona that were long thought to be Ammosaurus, and the type of Seitaad. This specimen is comparable to that of Segisaurus, the other named dinosaur body fossil from the formation: both are mostly torso and limbs. The name is a reference to a sand monster in Navajo mythology: the monster would bury its victims in sand dunes, while the dinosaur was probably buried in the collapse of a sand dune (probably already dead). One of the Arizona specimens is similar to Seitaad, but the other is distinct, indicating the presence of at least two taxa of sauropodomorphs. |
| Taxon or Taxa: | Time/Place: | Comments: |
| Eucnemesaurus fortis Hoepen, 1920 | early Norian (LTr) of South Africa | Eucnemesaurus is another lost name from the depths of prosauropod taxonomy limbo, recently brought back after much obscurity. It is based on a fragmentary partial skeleton, and is the same as erstwhile giant herrerasaurid Aliwalia rex Galton, 1985 (which was based on a partial femur, not anything distinctly meat-eaterish, although to be fair a toothy maxilla was thought to go to it as well, so there may well have been a really big archosaurian carnivore in the area). |
| Riojasaurus incertus Bonaparte, 1969 | late Norian (LTr) of Argentina | Traditionally considered to be the best-known "melanorosaurid", Riojasaurus has over twenty partial skeletons and one skull, the only one known for a "melanorosaurid", referred to it. However, new research indicates that it is a more basal animal, unlike Melanorosaurus. |
Massospondylidae: Unnamed possible massospondyls are known from Arizona (at least some of the old Ammosaurus cf. major stuff) and Nova Scotia (coincidentally enough, also once assigned to Ammosaurus).
| Taxon or Taxa: | Time/Place: | Comments: | |
| Massospondylus: Owen, 1854 |
M. carinatus (type) Owen, 1854 | Hettangian-Sinemurian (EJ) of Lesotho, South Africa, and Zimbabwe | One of the best-known prosauropods, Massospondylus
is known from a wealth of African material. Some North and South American bones
have been referred to it as well, including a
well-preserved skull from the Sinemurian-mid Pliensbachian (EJ) Kayenta Formation of
Arizona (now Sarahsaurus),
and material from Argentina (now Adeopapposaurus),
while some Navajo Sandstone [late Sinemurian-Pliensbachian {EJ}] material once assigned to Ammosaurus
[=Anchisaurus] also appears to have "massospondyl"
affinities. However, recent study of the South African skulls
indicates that the Kayenta skull belongs to something else. The
African skulls are characterized by relatively large eyes and a shortening
and deepening of the region in front of them, proportions that are quite
distinctive. The skull is frankly kind of short, squat, and blunt. M. kaalae is based on a skull, and raises the question of what else may be lurking in the dozens of specimens assigned to Massospondylus. Nearly hatched embryos assigned to Massospondylus show typically juvenile big head and eyes, but also have a clearly quadrupedal stance and lack teeth. The lack of teeth suggests they would have been fed by their parents for a period of time after hatching. Also, as the authors note, the stance suggests that quadrupedality in sauropods came from retention of juvenile characteristics (most basal sauropodomorphs could probably go bipedal for at least a short time if the mood struck them), as has also been suggested with some of the skull anatomy. |
| M. kaalae Barrett, 2009 | Hettangian-Sinemurian (EJ) of South Africa | ||
| Adeopapposaurus mognai Martínez, 2009 | EJ of Argentina | Adeopapposaurus represents what had been reported as Massospondylus fossils from Argentina in the early 2000s. It's known from enough material to get a very good picture of the skeleton; the type has a skull and most of the skeleton up to the proximal tail, and three other partial skeletons take care of most of the rest. The tips of the upper and lower jaw may have had keratinous beaks. | |
| Leyesaurus marayensis Apaldetti, Martinez, Alcober, and Pol, 2011 | LTr and/or EJ of Argentina | Leyesaurus is a massospondyl-type sauropodomorph represented by a skull, most of the neck, and some odds and ends (a couple of caudals, partial pectoral girdle and humerus, chunks of the lower pelvic girdle bones, and a partial foot). | |
| Coloradisaurus brevis Lambert, 1983 (originally Coloradia brevis Bonaparte, 1978) | late Norian (LTr) of Argentina | Based on a skull and ?postcranial remains, Coloradisaurus has sometimes been considered the adult form of Mussaurus, but this is unlikely. | |
| Glacialisaurus hammeri N. Smith and Pol, 2007 | EJ of Antarctica | The third named Antarctic dinosaur, Glacialisaurus is a massospondyl-type sauropodomorph, close to Coloradisaurus and particularly Lufengosaurus. It is based on an ankle and partial foot, with a referred femur. | |
| Lufengosaurus huenei Yang, 1941 | Hettangian-Sinemurian (EJ) of China | Possibly closely related to Plateosaurus, this prosauropod is known from over thirty partial skeletons and several skulls, but rarely gets much attention. It is also quite similar to Yunnanosaurus. Remains named "Gyposaurus" sinensis assigned here may be their own taxon. Lufengosaurus has sometimes been considered to be the same as Massospondylus or Yunnanosaurus, but these are both unlikely. | |
| Taxon or Taxa: | Time/Place: | Comments: |
| Anchisaurus polyzelus Marsh, 1885 (originally Megadactylus polyzelus Hitchcock, 1865) (including Ammosaurus major Marsh, 1891) | Hettangian-Sinemurian (EJ) of Connecticut and Massachusetts (yes, substantially older than usually depicted) | One of the rare New England classic dinosaurs, Anchisaurus
has been named both Megadactylus and Amphisaurus, generic names that
both turned out to be occupied by other things. It is based on a partial skeleton
and skull, one of the first known for a classic dinosaur. A dinosaur named Yaleosaurus coelurus (Huene, 1932, based on A. coelurus Marsh, 1891), now considered a junior synonym of Anchisaurus polyzelus, was at one time a common sight in dinosaur books. However, some material assigned to Yaleosaurus may belong to a distinct New England taxon that is a "prosauropod", not as derived as A. polyzelus. Species from the early Jurassic of Africa (A. capensis) and China (A. sinensis) were once referred here, but now appear to be the young of other sauropodomorphs, or their own taxa (the "gyposaurs"). Longtime Connecticut neighbor Ammosaurus major appears to be an individual variant of A. polyzelus. At one time, it was considered a "coelurosaurian," back when all small theropods were "coelurosaurs," but it has since been recognized as a sauropodomorph. Remains from Arizona which were once assigned to it appear to belong to at least one distinct taxon, probably a "massospondyl". Ammosaurus may make a comeback, though: Anchisaurus polyzelus is based on material that is not optimal, and the argument has been made to abandon it for Ammosaurus, the next name in line (see Marasuchus versus Lagosuchus. Made by the same researcher [Paul Sereno], too). Anchisaurus has long been considered a prosauropod, and a fairly basal one at that, but recent analysis puts near the base of Sauropoda, or a sauropod (depending on how you use the terminology). |
| Aardonyx celestae Yates, Bonnan, Neveling, Chinsamy, and Blackbeard, 2009 | ?Pliensbachian (EJ) of South Africa | Aardonyx is a derived basal sauropodmorph, on the cusp of going quadrupedal full-time. Its arms were heavily built and could support weight (very stocky forearms), and the hands could do some rotation, although it couldn't walk with them pointed fully forward. The skull lacked cheeks, like sauropods, but still had the narrow pointed form of basal sauropodomorphs. Aardonyx is known from two individuals from a bonebed. Interestingly, a femur from a truly quadrupedal sauropodmorph was also found in the quarry. |
| Leonerasaurus taquetrensis Pol, Garrido, and Cerda, 2011 | EJ (probably) of Argentina | Leonerasaurus is known from a partially articulated partial skeleton including a sampling of bones throughout the body (dentary and teeth, series of cervicals and dorsals, partial girdles, humerus, part of a femur, and bits and pieces). It was found in the Las Leoneras Formation (hence the name), which is usually thought to be middleish to late EJ in age, but may be closer to the Tr-J boundary, perhaps even from the LTr. Leonerasaurus was small; although the type individual, estimated at 2.5 m long, was not fully grown, it was not far from it. It had a sauropod-like sacrum. |
| Melanorosaurus readi Haughton, 1924 | early Norian (LTr) of South Africa | Long confused with Euskelosaurus, this was one of the largest land animals the world had ever seen before the Jurassic. Its hips were joined by four sacral verts, one more than in the prosauropods. In the past, it has been assigned to the family Melanorosauridae, in the Prosauropoda, but new research advocates breaking up that arrangement. |
Anchisauria i.s.:
| Taxon or Taxa: | Time/Place: | Comments: |
| Camelotia borealis Galton, 1985 | Rhaetian (LTr) of England | Based on remains once assigned to Avalonia sanfordi Seeley, 1898, this "melanorosaur" is still rather poorly known. It may be close to Melanorosaurus. |
Sauropoda: This group is probably one of the most familiar of classic dinosaurs to the public, although they may not know the proper terms. They are often called "brontosaurs," (thunder reptiles), an apt if incorrect name.
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