Author's note: these pages were written some years ago. I am not planning to update them. For a more current coverage, see the Palaeos website (to which many links on these pages point to anyway. More info here

Scutosaurus portrait from Russian Dinosaur Exposition

The Pareiasaurs were large late Permian herbivores.  They were heavy ungainly animals, frequently the size of an ox, with capacious bodies, strong limbs, broad feet, and thick solid skulls ornamented with bizarre knobs and ridges.  They were armoured with bony scutes or osteoderms set in the skin,   The largest types were 3 metres long and about 1 1/2 meters tall, with an advanced upright limb posture to support the weight of the body.

The leaf-shaped multi-cusped teeth (left) resembled those of iguanas, caesids, and other reptilian herbivores.  This dentition, together with the deep capacious body (which obviously housed an extensive digestive tract) are proof that these fearsome-looking animals were in reality inoffensive herbivores.

Pareiasaurs appear very suddenly in the fossil record.  It is clear that these animals evolved from Rhipaeosaurs to fill the large herbivore niche (or guild) that had been occupied early in the Permian period by the Caesid pelycosaurs and before then the Diadectid amphibians and Edaphosaur reptiles.  In fact it may well have been the extinction of the Caesids created an ecological vacuum that enabled the Pareiasaurs to appear and suddenly diversify as rapidly as they did (within the span of only two million years).   Although the last Pareiasaurs were no larger than the first types (indeed, many of the last ones became smaller), there was a definite tendency towards increase of armour as the group developed.

It has been often suggested that these animals were semi-aquatic.  Skeletons have been found in a standing position, indicating that the animals became mired in the mud and swamps while feeding on vegetation.  Their remains are also consistently found in channel stream deposits (riverbeds).  Of course, this does no mean that they were semi-aquatic; and actually the fact that the animals became stuck argues against aquatic adaptations (a aquatic animal would not likely become stuck, whereas a terrestrial animal would; e.g. the remains of sauropod dinosaurs, which were as terrestrial as elephants, are sometimes found in this position).  A more plausible explanation is that these were fully terrestrial animals that frequented watercourses in order to get at the succulent aquatic vegetation.

It has recently been argued that Pareiasaurs may have evolved into turtles.  They had turtle-like skull features, and several genera had bony plates in the skin, possibly the first signs of a turtle shell.  However, the case for turtle ancestry is not proven.

Recent reports of a slender stapes (a sound-conducting middle ear ossicle) indicate that pareiasaurs had an efficient ear drum (tympanum) and were able to hear high frequency airborne sounds.

Dinocephalian

Gorgonopsid

The skull is short, broad (laterally expanded), massive, and strongly sculptured and knobby.  The sutures are not clearly distinguishable.  The quadratojugals (cheekbones) project laterally downwards (almost like the hanging "jowls" on a cartoon "Looney Tunes" butler).  The orbits (eye sockets) are relatively small, and laterally (side of the head) placed.  There is an opening for the pineal body ("third eye", use to regulate metabolism in the case of seasonal extremes).  the brain-case is long and low, the ear-cavity separated by bone from the brain cavity.  The tabular and post-parietal bones of the skull are on the dorsal (upper) surface only.  The jaw articulation is well forward of the occipital condyle (the connection between the skull and vertebra), increasing the mechanical efficiency of the jaw musculature while decreasing the gape.

The palate (left) strongly integrated with the base of the braincase and the skull margins.  The bones of the palate are fused, and bear several series of small teeth.   The teeth are conical with leaf-shaped crowns.  Those on the margins of the jaws area arranged in a close regular series.

There are about eighteen presacral (neck and trunk) vertebrae, each with deep articulation for the ribs, and generally four sacral vertebrae.  The sacral vertebrae are unfused (an inefficient arrangement).  There are thirty caudal (tail) vertebrae with the anterior ones bearing short ribs.  Generally the tail is quite short.

The pelvic bones are massive and ossified.  The scapula is much longer than in other primitive tetrapods, and the pelvis has an almost mammalian configuration.  This may have helped accommodate muscles that moved the rear limb in a manner similar to the fore and aft gait of mammals.

The humerus is short, massive, and expanded at the ends; the ulna very stout.  The hind limbs are slightly shorter than the fore-limbs.  The stocky limbs are held close to the body to support the weight.  Both fore and hind feet have five digits, which are equipped with broad claws.

Remains of Pareiasaurs are quite common in the Lower Beaufort Series of South Africa, and a great many generic and specific names were originally proposed.  It would be very unlikely that such a large number of similar species would co-exist in the same time and space, and it is now recognised that many of these different types are actually the result of individual variation, growth stages, geological deformation of fossils, etc.  Now no more than five genera are recognised from South Africa, four from Russia, two from Europe and one from China.  Of course the original diversity of these animals would of been a lot greater, but it should be remembered that only a tiny fraction of all the species that ever lived have ever been fossilised, and only a fraction of them have been discovered as yet.  The following (still under construction) is a review of the dozen or so known genera of Pareiasauridae.

Family Pareiasauridae Lydekker 1889

Subfamily Bradysaurinae Huene 1948

Includes only the early genus Bradysaurus

Illustration from Fenton and Mildred Adams Fenton, 1958, The Fossil Book, Doubleday & Co., Garden City, New York,  p.306

Bradysaurus Watson 1914

comments: Despite its large size, Bradysaurus is actually the most primitive known genus of Pareiasaur.  The Bradysaurs can be considered the ancestral type from which the others developed, even if it lived at the same time as one or two other genera.  It can be assumed that Bradysaurus evolved somewhat earlier in time, during the Wordian epoch (Eodicynodon zone).  Fossils are rare in the Eodicynodon zone, which may explain its absence.

The skull is large, broad, flattened, and rounded at the front.  The skull-bones are coarsely sculptured and knobby, the sutures between them not clearly visible.  The marginal teeth are high-crowned with only a few cusps, this being a primitive characteristic.  The cusps consist of a terminal group of three cusps, the anterior with one to three and the posterior two to three cusps.

The phalangeal count is 2,3,3,3,2 on the fore-foot and 2,3,3,4,3 on the hind.  The whole body is covered in thin dermal scutes, which are quite smooth over the back.  The armour is not as heavily developed as in later forms.

The top of the ilium is vaulted.  There are 5 cervical, 15 dorsal, 4 sacral, and about 39 tail vertebrae.

Kuhn lists no less than nine species for this genus, but this is certainly an excessive number.  Boonstra distinguishes only four species on the basis of tooth structure, two of which Kuhn places in the genus Embrithosaurus.  I have decided to take the more cautious position and only have two species in this genus.

Bradysaurus baini (Seeley 1892) Lower to Upper Tapinocephalus zone, Lower Beaufort Beds, Karoo basin, South Africa This is the type species for the genus.  The quadrajugal region (cheek-bones) are only moderately developed.  The snout is broad and rounded.  There are 15 or 16 pairs of overlapping teeth in each jaw.  The genera Brachypareia, Bradysuchus, Koalemasaurus, Platyoropha would also seem to belong here.  Platyoropha and Brachypareia are indistinguishable from Bradysaurus.  The left-hand skull was originally described as Brachypareia watsoni,  Bradysuchus, is based on a pathological feature.  The skulls illustrated are 48 and 42 cm long

Bradysaurus seeleyi Haughton and Boonstra 1929 Tapinocephalus zone, Lower Beaufort Beds, South Africa Boonstra considered this a valid species of Bradysaurus.  The cheekbones are greatly enlarged and heavy.  There are 19 or 20 pairs of strongly overlapping teeth on each jaw.  This species clearly was not as common as B. baini.  Length of specimen at left 44 cm

Subfamily Pareiasaurinae Nopcsa 1923

 from Illustrated Encyclopaedia of Dinosaurs and Prehistoric Animals, illustration by Steve Kirk
graphic reproduced at  DinoSaurios

This subfamily includes the "typical" Pareiasaurs.  The heads decorated by knobs and ridges.  The teeth each have nine cusps.  The upper margin of the ilium is flat, never vaulted.  The surface of the back is armoured to varying degrees with bony scutes.  Some forms like the ancestral genus Embrithosaurus had only weak armour; while later forms like Pareiasaurus, Scutosaurus, and Anthodon were well protected.  The limb posture is advanced and upright to support the weight of the body (graviportal).

Dr Kuhn (Cotylosauria, p.75) includes the following genera: Pareiasaurus, Pareiasuchus (Dr Carroll includes this genus under Pareiasaurus), Embrithosaurus, Anthodon, Scutosaurus, Shihtienfenia, and Nanoparia.  Von Huene however places Scutosaurus, Shihtienfenia, and Nanoparia each in their own subfamilies.

Embrithosaurus Watson 1914

Embrithosaurus is another huge early Pareiasaur, a contemporary of Bradysaurus.  The skull is relatively deep and narrow
The body is lightly armoured with thin, smooth dermal scutes.   This genus would seem to be ancestral to Pareiasaurus.

Embrithosaurus strubeni (Broom, 1924) Lower to Upper Tapinocephalus zone, Lower Beaufort Beds, South Africa The skull is large and deep, pointed at the front, and elevated in the jugal region.  This species was originally made the type species of Nochelosaurus by Haughton and Boonstra.  Boonstra later (1969) moved it into the genus Bradysaurus, on the basis of the primitive tooth structure.  Kuhn however considers it belongs under Embrithosaurus The specimen 48 cm (left specimen), 35 cm (right)

Embrithosaurus angustus (Haughton and Boonstra 1929) Lower to Upper Tapinocephalus zone, Lower Beaufort Beds, South Africa As the name indicates, the skull is long and narrow.  This would seem to indicate a different lifestyle or diet to other parieasaurs.  This species was made the type for " Dolichopareia" Length about 55 cm

Embrithosaurus schwarzi Watson 1914 Lower to Upper Tapinocephalus zone The type species.  This is the most advanced species of this genus, as indicated by the teeth, which have nine cusps (in three groups of three).  The bony dermal plates are thin and smooth.  The ulna is without an olecranon process.

Pareiasaurus Watson 1914

comments: This genus includes a number of large Pareiasaurs.  The skull is broad and the snout short.  There are 4 sacral vertebrae.  The phalangeal count of the fore-foot is 2,3,3,3,2.  The armour is well developed, with several rows of heavy scutes.  There are 14 pairs of low, broad-crowned teeth, each with 9 to 13 or more cusps (depending on the species).

Pareiasaurus nasicornis  (Haughton and Boonstra 1929) Endothiodon  Zone, Karoo basin, South Africa early Amarassian Age This early form is one of the first representatives of the genus.  It was originally included under the genus Pareiasuchus.  The snout is heavily armoured, and bears a horn-like boss. The teeth are equipped with 11 (or possibly 13 or 15) cusps.  This is a large animal; the skull is about 50 cm in length.  This species might be ancestral to Pareiasaurus peringueyi.

Pareiasaurus peringueyi (Haughton and Boonstra 1929) Cistecephalus Zone, Karoo basin, South Africa Amarassian Age This species was the type species for Pareiasuchus.  It is represented by a nearly complete skeleton from the Zak River, South Africa.  It is a medium-sized animal, the skull being 36 cm long.  It  is distinguished especially by the large quadrato-jugal region inclined far outwards and forwards so that its lower border makes an angle of about 120o with the maxillary border; this cheek bears large bony bosses.  There are at least 13 pairs of teeth in the upper jaw, each with 13 or possibly 15 cusps

Pareiasaurus serridens Owen 1876 Daptocephalus Zone, Karoo basin, South Africa Dzulfian Age This late species is the type species for Pareiasaurus, and represents the culmination of this lineage.  The armour is well developed.  There are 14 pairs of teeth, each with 9 to 11 cusps.  The short deep skull is about 40 cm in length.  Note the extended quadrato-jugal region.

Anthodon Owen 1876

stratigraphic range and localities: Cistecephalus to Daptocephalus zones, Lower Beaufort Beds, Karoo basin, South Africa; Ruhuhuh valley, Tanzania; and Tatarian stage, northern Russia (Amarassian to Dzulfian age)
length: about 1.2 to 1.5 meters in length
weight: about 80 to 100 kg

comments: this small form combines the primitive feature of interpterygoid fenestra with an advanced feature of turtle-like armour.  The skull is small and quite lightly built.  The cheekbones extend downwards to a great degree, but with a smooth unornamented surface.  There are 11 to 14 pairs of overlapping teeth, each with 8 to 15 cusps.

Anthodon serrarius Owen 1876 Cistecephalus zone, Karoo basin, South Africa The type species, is known from an incomplete skull and several anterior vertebrae.  The teeth are regularly spaced and have at least 9 cusps each. Skull length 30 cm

Anthodon gregoryi Broom 1930 Middle? Cistecephalus zone, Karoo basin, South Africa A large species for this genus, known from an incomplete skull almost 30 cm wide.  The teeth only have have 8 cusps each.

"Anthodon" rossicus Hartmann-Weinberg 1933 = "Anthodon" chlynoviensis Efremov
Lower Zone IV - Tatarian stage, Russia (Dzulfian age)
This probably belongs to a distinct, perhaps unrelated, genus.

 from Illustrated Encyclopaedia of Dinosaurs and Prehistoric Animals, illustration by Steve Kirk
graphic reproduced at DinoSaurios

Scutosaurus Hartmann-Weinberg 1930

Illustration credits:  top: Oskar Kuhn, 1969, Cotylosauria, part 6 of Handbuch der Palaoherpetologie, Gustav Fischer Verlag, Stuttgart & Portland, p.79 left: R. L. Carroll, 1988, Vertebrate Paleontology and Evolution, W.H. Freeman & Co. New York, p.205 more  drawings of the skull of Scutosaurus here

The skull (left) is very broad, flat, and strongly sculptured, and bears bony protuberances in the jugal (cheek) and rear regions.  As with some species of Pareiasaurus, with which it is clearly related, the quadrato-jugal or cheekbones extend outwards and forwards, makings an angle of about 120o with the maxillary border.  The skull shown on the left is about 50 cm wide.

		The post-cranial skeleton (left) is well known.  There are 6 cervical, 13 dorsal, 5 (or 4?) sacral vertebrae, and only a few tail vertebrae
Illustration: R. L. Carroll, 1988, Vertebrate Paleontology and Evolution, W.H. Freeman & Co. New York, p.205	Illustration: Oskar Kuhn, 1969, Cotylosauria, Gustav Fischer Verlag, Stuttgart & Portland, p.69

Shihtienfenia Young and Yeh 1963
stratigraphic range: Shihtienfeng series (Dzulfian age)
locality:  Shansi province, China

The skull of this pareiasaur is unknown.  It is known from a number of isolated vertebrae, jaws, and limb-bones and an incomplete skeleton, all from a single locality.  Shihtienfenia is unusual because of the presence of 6, rather than the usual 4, sacral vertebrae, and may belong in a separate subfamily, although Oskar Kuhn includes it under the Pareiasaurines in his monograph.  As with the Pareiasaurines the upper margin of the ilium is flat.  No dicynodonts are found in association, so these animals obviously lived in a separate environment.

Subfamily Elgininiinae Cope 1895

 from Illustrated Encyclopaedia of Dinosaurs and Prehistoric Animals, illustration by Steve Kirk
graphic reproduced at DinoSaurios

This is a small specialised late lineage, characterised by large spikes or backwardly curved "horns".  They are known from the late Dzulfian age of Northern Pangea (Scotland and Russia).  In the Moscow Basin (middle part of the Vyatskian horizon), Elgiinine pareiasaurs are associated with therapsids like Nanocynodon and Dicynodon, Proterosuchid Archosaurs, and Bystrowianid amphibians.  They would represent a slightly later (say a million years or so) time period than that of the giant Scutosaurs.

Unfortunately I do not have any more information at the moment on the Russian Elginiine parieasaurs.  Here is the reference for the original paper (which I do not have access to:  Ivachnenko, M.,F., 1992, "Late Permian faunistic complexes of tetrapods of East Europe and it's Gondwanan analogues", In: Paleontology and Stratigraphy of the Continental Permian and Triassic Deposits of Northern Eurasia, Abstracts, Moscow, pp.14-15

Elginia Newton 1892
stratigraphic range: Elgin Formation (Dzulfian age)
locality: Scotland
length: 60 cm long
weight: about 8 or 10 kg
more on Elginia

comments: These small parieasaurs represent the specialised end of the line for these great herbivores.  The increasing aridity of the later Permian was drying up the swamps and pools where they liked to feed.

Illustration credits:  top: illustration from Oskar Kuhn, 1969, Cotylosauria, Gustav Fischer Verlag, Stuttgart & Portland, p.74 left: illustration from Karl A. Von Zittel, Text-Book on Paleontology, Macmillan & Co., London,  vol.2 , pp.242

The type and only species - Elginia mirabilis Newton, is known only by the skull, which is about 15 cm long, triangular, coarsely sculptured, and armed with a number of paired bosses or spines.  The upper jaw bears 12 pairs of teeth, each with 9 or 10 cusps.  The teeth are slightly constricted at the base and serrated at the crown.

Subfamily Pareiasaurinae or Elgininiinae

Nanoparia Broom 1936 stratigraphic range: Daptocephalus Zone, Lower Beaufort Beds (Dzulfian age) locality:  Karoo basin, South Africa length: 60 cm weight: about 8 or 10 kg This is an unusual small, spiny specialised form.  The skull is very similar to that of Pareiasaurus and Romer considered it a synonym of the latter.  Orlov however (in Osnovy Paleontology, the monumental multivolume Russian textbook of Paleontology) placed it in the Elginiinae.  Kuhn however argues that while resembling Elginia in the ossifications at the rear of the skull, it differs completely in proportions and would not seem to be related at all. Type species: Nanoparia luckhoffi Broom 1936 (Nanoparia pricei Broom and Robinson 1948 illustrated left would almost certainly be synonymous).  Length of skull 12 cm. Illustration: Oskar Kuhn, 1969, Cotylosauria, part 6 of Handbuch der Palaoherpetologie, Gustav Fischer Verlag, Stuttgart & Portland, p.79

Deltavjatia vjatkensis "A recently discovered pareiasaur with numerous turtle-like skull features (e.g., a very high palate), limbs, and girdles, and lateral projections flaring out some of the vertebrae in a very shell-like way." from  Transitional Vertebrate Fossils FAQ by Kathleen Hunt	Anthodon  showing pattern of armour plates on the back reminiscent of a  turtle shell.  (Scale bar 30 cm)  from UCMP's  Introduction to Pareiasauria

References- Pareiasauria - Links -

L. D. Boonstra, 1969, "The Fauna of the Tapinoephalus Zone (Beaufort Beds of the Karoo)," Ann. S. Afr. Mus. 56 (1) 1-73, pp. 29-32

Robert L. Carroll, 1988, Vertebrate Paleontology and Evolution, W.H. Freeman & Co. New York, p.205

Edwin H. Colbert, 1965, The Age of Reptiles,  The World Naturalist, Weidenfeld and Nicolson, London,  pp.52-3

Barry Cox, R.J.G.Savage, Brian Gardiner, Dougal Dixon, 1988 Illustrated Encyclopaedia of Dinosaurs and Prehistoric Animals

Carol Lane Fenton and Mildred Adams Fenton, 1958, The Fossil Book, Doubleday & Co., Garden City, New York,  p.306

Prof. Oskar Kuhn, 1969, Cotylosauria, part 6 of Handbuch der Palaoherpetologie (Encyclopedia of Palaeoherpetology), Gustav Fischer Verlag, Stuttgart & Portland,

Michel Laurin, 1996, " Introduction to Pareiasauria - An Upper Permian group of Anapsids" - http://www.ucmp.berkeley.edu/anapsids/pareiasauria.html

Vladlen R. Lozovsky, 1998, "The Permian-Triassic boundary in the continental series of Eurasia", Palaeogeography, Palaeoclimatology, Palaeoecology, 143 (1998) pp.273-283

The Russian Dinosaur Exposition -  "Scutosaurus karpinski" - http://www.mathematical.com/dinoscutosaurus.html

Toby White - "Pareiasaurs" - Palaeos - Halucinocrania: Pareiasaurs

Karl A. Von Zittel, Text-Book on Paleontology, Macmillan & Co., London,  vol.2 , pp.241-243

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