458:
1359:
1084:
129:
1490:
appeared on their fifth tail vertebra. Although it was possible that genital size was variable among males to the extent of impacting the skeleton, the more likely explanation was that the differences White had observed were caused by individual skeletal variation, evolutionary divergence, or some other factor unrelated to sexual dimorphism. Likewise, they agreed that skull proportions supported Vaughn (1966)'s proposal that dimorphism was present in
4059:
1108:(joint plates) about three times as wide as the pleurocentrum itself. Some vertebrae have neural spines which are partially subdivided down the middle, while others are oval-shaped in horizontal cross-section. The ribs of the dorsal vertebrae extend horizontally and attach to the vertebrae at two places: the intercentrum and the side of the neural arch. The neck is practically absent, only a few vertebrae long. The first neck vertebra, the
893:
781:
4081:
1377:'s skeleton. He argued that the robust limbs and wide-set body supported the idea that it was a strong, terrestrial animal with a sprawling gait. However, he also noted that Permian trackways generally support the idea that terrestrial tetrapods from this time period were not belly-draggers, but instead were strong enough to keep their bodies off of the ground. As with other paleontologists around the time, Romer assumed that
1048:(holes leading from the nasal cavity to the mouth) were large and close together, as in amniotes. The palate is generally solid bone, with only vestigial interpteryoid vacuities (a pair of holes adjacent to the midline) separated by a long and thin cultriform process (the front blade of the base of the braincase). Apart from the fangs, the palate is also covered with small denticles radiating out from the rear part of the
673:
4071:
1164:(wrist) has ten bones, and the hand has five stout fingers. The carpal bones are fully developed and closely contact each other, another indication of terrestriality. The phalanges (finger bones) decrease in size towards the tip of the fingers, where they each end in a tiny, rounded segment, without a claw. The phalangeal formula (number of phalanges per finger, from thumb to little finger) is 2-3-4-4-3.
1005:(eardrum) which presumably lay within the otic notch. In this way it could transmit sound from the outside world to the brain. The configuration of the stapes is intermediate between non-amniote tetrapods and amniotes. On the one hand, its connection to the otic notch is unusual, since true reptiles and other amniotes have lost an otic notch, forcing the tympanum and stapes to shift downwards towards the
854:
4076:
4087:
1474:(bony spines on the underside of the tail vertebrae) which first appeared on the third tail vertebra, while other specimens had them first appear on the sixth. He postulated that the later appearance of the chevrons in some specimens was indicative that they were males in need of more space to store their internal genitalia. This type of sexual differentiation has been reported in both
1240:
4066:
1144:(forearm bone) was shaped like a boxy and slightly twisted L, with large areas for muscle attachment. This form, which has been described as "tetrahedral", is plesiomorphic for tetrapods and contrasts with the slender hourglass-shaped humerus of amniotes. On the other hand, the lower part of the humerus also has a reptile-like adaptation: a hole known as an
104:
1279:. The combination of features from both species in these specimens may indicate that the two species are part of a continuous lineage, rather than two divergent evolutionary paths. Likewise, some differences relating to the proportions of the rear of the skull may be considered to be an artifact of the fact that most
1064:
re-investigation of one of the Cutler
Formation specimens. Neither of these traits are the standard in amniotes. The braincase had a mosaic of features in common with various tetrapodomorphs. The system of grooves and nerve openings on the side of the braincase were unusually similar to those of the fish
1388:
White (1939) elaborated on biological implications. He noted that the presence of an otic notch reduces jaw strength by lowering the amount of surface area jaw muscles can attach to within the cranium. In addition, the skull would have been more fragile due to the presence of such a large incision.
1405:
had low-slung limbs and a wide, top-heavy body that would have otherwise been vulnerable to torsion when it was walking. This may also explain the presence of this trait in captorhinids, diadectomorphs, and other "cotylosaurs". Perhaps swollen vertebrae were an interim strategy to prevent torsion,
1116:
vertebra (as in amniotes), the low bone development in this area of the neck contrasts with the characteristic atlas-axis complex of amniotes. In addition, later studies found that the atlas intercentrum was divided into a left and right portion, more like that of amphibian-grade tetrapods. Unlike
1103:
between the hip and skull. The vertebrae are gastrocentrous, meaning that each vertebra has a larger, somewhat spool-shaped component known as a pleurocentrum, and a smaller, wedge-shaped (or crescent-shaped from the front) component known as an intercentrum. The neural arches, which lie above the
954:
bones (known as otic flanges). The tabular also has a second downturned flange visible from the rear of the skull; this flange (known as an occipital flange) connected to the braincase and partially obscured the space between the braincase and the side of the skull. The development of the otic and
1489:
However, Berman, Reisz, & Elberth (1987) criticized the methodologies of White (1939) and Vaughn (1966). They argued that White's observations were probably unrelated to the sex of the animals. This was supported by the fact that some of the Cutler
Formation specimens had chevrons which first
1445:
fossils while also completely lacking aquatic animals. They also pointed out the well-developed wrist and ankle bones of the "Tambach lovers" as supportive of terrestrial affinities. Despite the strong musculature of the forelimbs, Romer (1928) and White (1939) found little evidence for burrowing
867:
individuals were robustly-built animals, with a large head, short neck, stocky limbs, and broad feet. Even the largest specimens were fairly small, only about 2 ft (60 cm) long. The skull was boxy and roughly triangular when seen from above, but it was lower and longer than that of most
1167:
Two sacral (hip) vertebrae were present, though only the first one possessed a large, robust rib which contacted the ilium (upper blade of the hip). Some studies have argued that there was only one sacral vertebra, with the supposed second sacral actually being the first caudal due to having a
1063:
The lower jaw retained a few plesiomorphic characteristics. For example, the inner edge of the mandible possessed three coronoid bones. The mandible also retained at least one large hole along its inner edge known as a meckelian fenestra, although this feature was only confirmed during a 2005
1196:. These begin to appear in the vicinity of the third to sixth caudal, depending on the specimen. Ribs are only present within the first five or six caudals; they are long at the base of the tail but diminish soon afterwards and typically disappear around the same area the chevrons appear.
1211:
can be distinguished from each other based on several differences in the shape and connections between the different bones of the skull. For example, the downturned flange of bone above the otic notch (sometimes termed the "tabular horn" or "otic process") is much more well-developed in
1525:'s biology. A femur was found to have an internal structure characterized by a lamellar matrix pierced by numerous plexiform canals. Rest lines of slow growth are indistinct and closely spaced, but there is no evidence that growth ceased at any time during bone development. Like most
1172:
is low and teardrop-shaped when seen from the side, while the underside of the hip as a whole is formed by a single robust puboischiadic plate, which is rectangular when seen from below. Both the hip and shoulder sockets were directed at 45 degrees below the horizontal. The
970:(eye sockets) were about midway down the length of the skull, although they were a bit closer to the snout in juveniles. They were more rhomboidal than the circular orbits of other seymouriamorphs, with an acute front edge. Several authors have noted that a few specimens of
1040:(roof of the mouth) had some similarities with both amniote and non-amniote tetrapods. On the one hand, it retained a few isolated large fangs with maze-like internal enamel folding, as is characteristic for "labyrinthodont" amphibians. On the other hand, the
419:
not a true reptile, but rather an amphibian (in the traditional, paraphyletic sense of the term). At that time, it was still thought to be closely related to reptiles., and many recent studies still support this hypothesis. If this hypothesis is correct,
385:, and that certain adaptations of the limbs, hip, and skull were also similar to that of early reptiles, rather than any species of modern or extinct amphibians known at the time. The strongly-built limbs and backbone also supported the idea that
1112:, had a small intercentrum as well as a reduced pleurocentrum which was only present in mature individuals. Although the atlantal pleurocentrum (when present) was wedged between the intercentrum of the atlas and intercentrum of the succeeding
605:(1925) supported a placement among the Amphibia, but most studies around this time tentatively considered it an extremely "primitive" reptile; these included a comprehensive redescription of material referred to the species, published by
938:, and a similar incision in the same general area is common to most Paleozoic amphibians ("labyrinthodonts", as they are sometimes called), but unknown in amniotes. The lower edge of the otic notch was formed by the
1001:, a rod-like bone which lies between the braincase and the wall of the skull, was tapered. It connected the braincase to the upper edge of the otic notch, and likely served as a conduit of vibrations received by a
1400:
White also drew attention to the unusual swollen vertebrae, which would have facilitated lateral (side-to-side) movement but prohibit any torsion (twisting) of the backbone. This would have been beneficial, since
868:
other seymouriamorphs. The vertebrae had broad, swollen neural arches (the portion above the spinal cord). As a whole the body shape was similar to that of contemporary reptiles and reptile-like tetrapods such as
1189:(ankle) incorporates 11 bones, intermediate between earlier tetrapods (which have 12) and amniotes (which have 8 or fewer). The five-toed feet are quite similar to the hands, with phalangeal formula 2-3-4-5-3.
836:
fossilized lying next to each other (though it cannot be determined whether they were a couple killed during courtship). The
Tambach Formation has also produced the developmentally youngest known fossils of
465:
as a primitive egg-laying terrestrial reptile, from a series of paintings by F.L. Jaques illustrating the "progressive" stages of evolution from fish to man for the
American Museum of Natural History in the
600:
was central to the evolutionary transition between the two groups. Regardless, not enough was known about its biology to conclude which group it was truly part of. Broom (1922) and
Russian paleontologist
757:, described a year earlier from a braincase found in Texas, has not been re-referred to any other tetrapod, but it remains poorly known. Langston (1963) reported a femur indistinguishable from that of
1494:
fossils, though they disagreed with how he linked it to sex using a fossil which was considered "female" under White's criteria. The discovery of fossilized larval seymouriamorphs has shown that
1393:
was capable of tackling large, active prey. Nevertheless, the sites for muscle attachment on the palate were more well-developed than those of contemporaneous amphibians. White extrapolated that
832:
s fossils of a similar quality to those of the Cutler
Formation. For example, in 2000 Berman and his colleagues described the "Tambach Lovers", two complete and fully articulated skeletons of
1397:
was a mostly carnivorous generalist and omnivore, feeding on invertebrates, small fish, and perhaps even some plant material. It may have even been cannibalistic according to his reckoning.
1482:
females gave birth to large-yolked eggs on land, as with turtles and crocodilians. Vaughn (1966) later found a correlation between chevron acquisition and certain skull proportions in
1056:
has a few amniote-like characteristics of the palate, such as the presence of a prong-like outer rear branch of the pterygoid (formally known as a transverse flange) as well as an
2616:"Inner ear morphology of diadectomorphs and seymouriamorphs (Tetrapoda) uncovered by high-resolution x-ray microcomputed tomography, and the origin of the amniote crown group"
1333:
has a taller snout, and its teeth are generally much larger, less numerous, and less homogenous in size. The palate is generally similar between the two species, although the
513:
in 1904 based on a pair of incomplete skulls, one of which was associated with a few pectoral and vertebral elements. These fossils were described by German paleontologist
1060:
which is separate from the pterygoid. However, these characteristics have been observed in various non-amniote tetrapods, so they do not signify its status as an amniote.
1013:'s stapes is a specialization over most non-amniote tetrapods, which have a thick stapes better suited for reinforcing the skull rather than hearing. The inner ear of
4205:
457:
4269:
1895:(Seymouriamorpha) from the Lower Permian of Germany based on complete, mature specimens with a discussion of paleoecology of the Bromacker locality assemblage".
1827:(Amphibia, Batrachosauria) from the Lower Permian Cutler Formation of north-central New Mexico and the occurrence of sexual dimorphism in that genus questioned"
1192:
There were only about 20 caudal (tail) vertebrae at most. Past the base of the tail, the caudals start to acquire bony spines along their underside, known as
1220:. In the former species, it acquires a triangular shape (when seen from the side) as it extends downwards more extensively towards the rear of the skull. In
1594:
1410:
are in line with this hypothesis. Nevertheless, these vertebrae were inefficient at defending against torsion at any speed faster than a brisk walk, so
642:'s classification, placing it among the amphibians rather than the reptiles. Perhaps the most damning evidence came in 1952, when Czech paleontologist
1329:, the maxilla was low, with many sharp, closely spaced teeth extending along its length. This condition is similar to other seymouriamorphs. However,
354:
is more abundant and widespread. This smaller species is known from multiple well-preserved fossils, including a block of six skeletons found in the
4192:
2849:
2317:"On the representatives of the Seymouriamorpha, supposed primitive Reptiles, from the Upper Permian of Russia, and on their phylogenetic relations"
4264:
1136:(bony plates which lie above and below the shoulder socket, respectively) are separate bones, rather than one large shoulder blade. Likewise, the
4274:
2439:
2218:
Gregory, William King (1931) "Students in Nature's
Training School" in American Museum of Natural History Hall of Human Evolution guide book
974:
possessed indistinct grooves present in bones surrounding the orbits and in front of the otic notch. These grooves were likely remnants of a
1563:
are inferred to have undergone metamorphosis very early in life, likely due to environmental stresses from fluctuating wet and dry seasons.
1358:
2427:
596:" amphibians. This combination of features from reptiles (i.e. other "cotylosaurs") and amphibians (i.e. embolomeres) was evidence that
490:, referring to both the town and county). The earliest fossils of the species to be collected were a cluster of individuals acquired by
116:
529:", a taxon he had recently named from fragmentary limbs and vertebrae, likely represented juvenile or even embryonic individuals of
2162:"Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix"
1425:
was also a good swimmer, since he (erroneously) estimated that the animal had a deep and powerful tail similar to that of modern
917:
2105:
Marsicano, Claudia A.; Pardo, Jason D.; Smith, Roger M. H.; Mancuso, Adriana C.; Gaetano, Leandro C.; Mocke, Helke (July 2024).
616:
was not biologically reptilian started to emerge by the 1940s. Around this time, several newly described genera were linked to
428:
documenting the acquisition of reptile-like skeletal features prior to the evolution of the amniotic egg, which characterizes
934:
reptiles. In addition, the rear part of the skull had a large incision stretching along its side. This incision is termed an
1121:
completely lacks any bony remnants of scales or scutes, not even the thin, circular belly scales of other seymouriamorphs.
1083:
2571:
Klembara, Jozef; Berman, David S.; Henrici, Amy C.; Cernansky, Andrej; Werneberg, Ralf; Martens, Thomas (30 March 2007).
2259:
2842:
1283:
specimens were not fully grown prior to the discovery of the "Tambach lovers", which were adult members of the species.
880:. Collectively these types of animals have been referred to as "cotylosaurs" in the past, although they do not form a
4080:
1381:
had a reptilian (or amniote) mode of reproduction, with eggs laid on dry land and protected from the elements by an
4058:
2705:"Morphology of the atlas-axis complex of the late Palaeozoic tetrapod suborders Diadectomorpha and Seymouriamorpha"
2219:
491:
128:
2614:
Klembara, Jozef; Hain, Miroslav; Ruta, Marcello; Berman, David S.; Pierce, Stephanie E.; Henrici, Amy C. (2019).
2460:
1908:
576:
known as "cotylosaurs", which also included many other stout-bodied
Permian reptiles or reptile-like tetrapods.
4259:
2947:
1589:
1533:
is open and has a small amount of spongiosa bone. The development of spongiosa bone is slightly higher that of
1406:
which would later be supplanted by strong hip muscles in later reptiles. The rather undeveloped hip muscles of
1232:
by means of an obtuse, wedge-like suture, while the connection between the two bones is completely straight in
522:
2681:
982:. Many specimens do not retain any remnant of their lateral lines, not even juveniles. Near the middle of the
2592:
2835:
2432:: First vertebrate evidence for correlation of Upper Permian continental strata of North America and Russia"
1367:
1072:
978:
system, a web of pressure-sensing organs useful for aquatic animals, including the presumed larval stage of
4070:
1267:(for example, the "Tambach lovers") also had small postparietals. In addition, the "Tambach lovers" have a
4145:
4075:
1429:. However, he also noted that it would have been vulnerable to semiaquatic or aquatic predators, and that
1145:
912:
was very similar to that of far more ancient tetrapods and tetrapod relatives. For example, it retains an
1779:
1030:
634:
itself had occasionally been argued to possess lateral lines, sensory structures only usable underwater.
4231:
1334:
4086:
1091:
specimen. Note that the fourth finger of the hand is too long and too many caudal ribs are illustrated.
808:, as described by Berman, Reisz, & Eberth (1987). In 1993, Berman & Martens reported the first
689:
3941:
2316:
2289:
4065:
3437:
2716:
2542:
2448:
2347:
2118:
2071:
2024:
1960:
1838:
1635:
1022:
908:
The skull was composed of many smaller plate-like bones. The configuration of skull bones present in
762:
697:
479:
389:
was primarily terrestrial, spending very little time in the water. However, in the 1950s, fossilized
3764:
2397:
4023:
3899:
3701:
2485:
1709:
1321:
The tooth-bearing maxilla bone, which forms the side of the snout, is also distinctively unique in
1026:
729:
656:, and thus were amphibians, biologically speaking. Nevertheless, the numerous similarities between
545:
510:
425:
3934:
3927:
3828:
3672:
1075:
perforate the braincase near the rear of the bone complex, a derived feature similar to amniotes.
643:
3987:
3813:
3385:
2685:
2596:
2511:
2371:
2040:
1984:
1976:
1920:
1912:
1751:
1651:
1268:
1002:
947:
913:
573:
260:
123:
3857:
3686:
1891:
Berman, David S.; Henrici, Amy C.; Sumida, Stuart S.; Martens, Thomas (2000). "Redescription of
1433:
fossils were more common in terrestrial deposits as a result of its habitat preferences. Berman
4236:
3378:
2464:
4218:
4210:
3865:
3792:
3590:
3571:
3328:
2783:
2765:
2637:
2363:
2201:
2183:
2142:
2134:
2087:
1471:
1459:
1438:
1193:
1186:
1057:
966:
The sensory apparatus of the skull also deserves mention for an array of unique features. The
821:
708:. Fossils of this species are now understood to be more abundant and widespread than those of
606:
363:
4223:
2805:
A photograph of the "Tambach lovers" specimen, published by Mark MacDougall's twitter account
4103:
3843:
3821:
3550:
3350:
2773:
2755:
2724:
2677:
2627:
2588:
2550:
2533:(Vertebrata: Seymouriamorpha) from Early Permian fissure fills at Richards Spur, Oklahoma".
2501:
2456:
2355:
2297:
2191:
2173:
2126:
2079:
2032:
1968:
1904:
1846:
1742:
from the Lower
Permian of Southeastern Utah, and Possible Sexual Dimorphism in That Genus".
1687:
1643:
1530:
1466:, but others are unconvinced by this hypothesis. White (1939) argued that some specimens of
1303:
1225:
1096:
801:
677:
593:
514:
355:
2744:"Postcranial anatomy and histology of Seymouria, and the terrestriality of seymouriamorphs"
1286:
Nevertheless, several traits are still clearly differentiated between the two species. The
3799:
3708:
3600:
3311:
3235:
3122:
3078:
2932:
2660:
Klembara, Jozef; Berman, David S.; Henrici, Amy C.; Cernansky, Andrej (30 December 2005).
2423:
1421:
to be quite competent on land, he also discussed a few other lifestyles. He supposed that
1125:
1109:
967:
892:
780:
741:
635:
621:
537:
404:
303:
173:
4183:
2814:
2809:
2804:
2720:
2546:
2452:
2351:
2122:
2075:
2028:
2009:"The external gills and ornamentation of skull roof bones of the Lower Permian tetrapod
1964:
1842:
1639:
4118:
4113:
3913:
3883:
3785:
3694:
3649:
3473:
3335:
3321:
3272:
3203:
3166:
3007:
2985:
2959:
2858:
2815:
A photograph of the Cutler
Formation block, published by "mskvarla36"'s twitter account
2778:
2743:
2301:
2196:
2161:
1691:
1547:
1113:
1049:
939:
873:
648:
475:
395:
1539:(a terrestrial amphibian), but is much less extensive than aquatic amphibians such as
1314:
closely corresponds to the condition in other seymouriamorphs, while the condition in
4253:
3892:
3850:
3737:
3715:
3663:
3642:
3614:
3564:
3399:
3279:
3251:
3244:
3210:
3141:
3089:
3067:
2907:
2704:
2661:
2572:
2419:
2375:
1988:
1924:
1822:
1655:
1514:
1287:
1252:
1229:
1149:
1137:
1006:
983:
931:
869:
813:
774:
737:
713:
382:
334:
was first thought to be a primitive reptile. It is primarily known from two species,
311:
61:
2742:
Bazzana, Kayla D.; Gee, Bryan M.; Bevitt, Joseph J.; Reisz, Robert R. (2020-03-10).
2689:
2600:
2515:
2044:
1160:, as is common in terrestrial tetrapods but rare in amphibious or aquatic ones. The
4123:
4108:
3920:
3836:
3806:
3757:
3543:
3515:
3443:
3224:
3189:
3100:
3024:
2898:
1526:
1373:
Romer (1928) was among the first authors to discuss the biological implications of
1169:
1161:
1105:
1066:
987:
975:
951:
930:. The skull bones were heavily textured, as was typical for ancient amphibians and
877:
745:
672:
660:
and reptiles supported the idea that seymouriamorphs were close to the ancestry of
602:
561:
553:
378:
227:
2060:"Dates, nodes and character conflict: Addressing the Lissamphibian origin problem"
986:
was a small hole known as a pineal foramen, which held a sensory organ known as a
853:
568:
was too popular within the scientific community to be replaced. During this time,
1298:
have a branch of the lacrimal which extends a small distance under the orbit. In
494:
in 1882. However, these fossils would not be properly prepared and identified as
4177:
3906:
3872:
3778:
3771:
3723:
3679:
3635:
3621:
3506:
3487:
3425:
3293:
3258:
3196:
3182:
2220:
https://archive.org/details/scienceguide7692amer/page/n394/mode/1up?view=theater
1541:
36:
2827:
2130:
1033:. These features are more primitive than those of true reptiles and synapsids.
4128:
4005:
3529:
3413:
3364:
3217:
3111:
3057:
2819:
2490:(Amphibia: Batrachosauria) in the Lower Permian Rotliegend of central Germany"
2359:
2083:
1426:
1239:
935:
927:
922:
805:
749:
589:
359:
81:
46:
4168:
2769:
2641:
2367:
2187:
2138:
2106:
2091:
346:, is more robust and specialized, though its fossils have only been found in
3969:
3750:
3628:
3536:
3371:
3357:
3342:
3286:
3265:
3175:
3155:
3046:
3035:
2107:"Giant stem tetrapod was apex predator in Gondwanan late Palaeozoic ice age"
2059:
1510:
1157:
626:
319:
140:
86:
2787:
2728:
2205:
2146:
1071:
and the cartilaginous base is another plesiomorphic feature. However, the
381:
noted how the general body shape resembled that of early reptiles such as
4162:
3607:
3557:
3495:
3406:
2916:
2889:
1535:
1518:
1133:
1100:
733:
725:
160:
76:
71:
56:
51:
41:
1980:
1559:, and have a low amount of cartilage despite a high amount of porosity.
4197:
4029:
3956:
3522:
3460:
2810:
Another photograph of the "Tambach lovers", published by "Geology Page"
2760:
2662:"New structures and reconstructions of the skull of the Seymouriamorph
2632:
2615:
2178:
2036:
1916:
1755:
1185:
are robust, hourglass-shaped bones similar to the radius and ulna. The
1141:
1129:
1018:
825:
661:
444:
is a stem-tetrapod, it has little relevance to the origin of amniotes.
429:
390:
367:
327:
307:
296:
103:
91:
66:
30:
2709:
Philosophical Transactions of the Royal Society B: Biological Sciences
1498:
likely had an aquatic larval stage, debunking earlier hypotheses that
1009:
of the jaw joint. On the other hand, the thin, sensitive structure of
777:
Quarry in Oklahoma, as first described by Sullivan & Reisz (1999).
377:
was considered one of the oldest and most "primitive" known reptiles.
3993:
2883:
2506:
2290:"On the Persistence of the Mesopterygoid in certain Reptilian Skulls"
1475:
1382:
1302:, much of the rear edge of the orbit is formed by the chevron-shaped
1290:, in front of the eyes, only occupies the front edge of the orbit in
1182:
1045:
1044:
bones at the front of the mouth were fairly narrow, and the adjacent
1037:
998:
943:
766:
518:
433:
315:
150:
4139:
2554:
1947:
Romer, Alfred S. (1928). "A Skeletal Model of the Primitive Reptile
1850:
1584:
525:
later described a nearly complete skeleton in 1911, and noted that "
2008:
1972:
1647:
646:
reported gills preserved in juvenile fossils of the seymouriamorph
588:'s allegiance with the reptiles, noting many similarities with the
2703:
Sumida, Stuart S.; Lombard, Eric; Berman, David S. (29 May 1992).
2577:(Seymouriamorpha: Seymouriidae) at an early juvenile growth stage"
1357:
1178:
1174:
1082:
1041:
881:
852:
716:, although their validity has been more questionable than that of
671:
653:
501:
Various paleontologists from around the world recovered their own
483:
456:
412:
347:
299:
1486:, and proposed that they too were examples of sexual dimorphism.
1478:
and crocodilians. Based on this, he also supported the idea that
4033:
2402:
Bulletin of the Museum of Comparative Zoology at Harvard College
1153:
1104:
pleurocentra, are swollen into broad structures with table-like
701:
652:. This unequivocally proved that seymouriamorphs had an aquatic
437:
4143:
2876:
2831:
1140:
was flat and mushroom-shaped, with a long and thin "stem". The
2338:
Watson, D. M. S. (1942). "On Permian and Triassic Tetrapods".
1784:, the best known Seymouriamorph (Vertebrata: Seymouriamorpha)"
1821:
Berman, David S.; Reisz, Robert R.; Eberth, David A. (1987).
1156:
is similar, but longer due to the possession of a pronounced
1117:
almost all other Paleozoic tetrapods (amniote or otherwise),
1029:
was likely encompassed by a cartilaginous (rather than bony)
2529:
Sullivan, Corwin; Reisz, Robert R. (1999). "First record of
2461:
10.1130/0016-7606(2001)113<1229:trmfve>2.0.co;2
1909:
10.1671/0272-4634(2000)020[0253:ROSSSF]2.0.CO;2
2321:
Occasional Papers of the Boston Society of Natural History
684:
skeletons, described by Berman, Reisz, & Eberth (1987)
2682:
10.2992/0097-4463(2005)74[217:NSAROT]2.0.CO;2
505:
fossils in the late 19th century and early 20th century.
2820:
Translated DW documentary on Tambach fossils, including
2593:
10.2992/0097-4463(2007)76[53:FDOSOL]2.0.CO;2
572:
was generally seen as a very early reptile, part of an
2484:
Berman, David S.; Martens, Thomas (25 February 1993).
638:(1942) and Romer (1947) each reversed their stance on
556:(1922) argued that the genus should be referred to as
1168:
shorter, more curved rib than the first sacral. Each
3734:
3660:
3586:
3470:
3308:
3138:
3118:
3107:
3096:
3085:
3074:
3063:
3053:
3042:
3031:
3020:
2160:
Marjanović, David; Laurin, Michel (4 January 2019).
1128:
has several reptile-like features. For example, the
245:
234:
219:
4152:
4004:
3968:
3955:
3882:
3733:
3659:
3585:
3505:
3469:
3458:
3423:
3307:
3234:
3165:
3137:
3005:
2958:
2931:
2058:Ruta, Marcello; Coates, Michael I. (January 2007).
1555:'s vertebrae are more robust in shape compared to
440:). However, under the alternative hypothesis that
370:, which were fossilized lying next to each other.
1710:"Permische Stegocephalen und Reptilien aus Texas"
942:, while the upper edge was formed by downturned
920:("primitive") condition present in animals like
2294:Proceedings of the Zoological Society of London
1951:, and the Phylogenetic Position of that type".
1680:Proceedings of the Zoological Society of London
1310:. The shape of the lacrimal and postorbital of
773:-like skeletal remains are also known from the
362:, and a pair of fully grown skeletons from the
1087:A skeletal illustration of Williston (1911)'s
2843:
2573:"First description of skull of Lower Permian
2268:Bulletin of the Museum of Comparative Zoology
407:. This shows that seymouriamorphs (including
326:were well-adapted to life on land, with many
8:
724:(Olson, 1980), known from a nearly complete
1780:"A Redescription of the Cranial Anatomy of
1437:. (2000) supported this hypothesis, as the
845:, which is known primarily from juveniles.
712:. Several more species were later named by
704:. These remains represented a new species,
630:, had evidence of aquatic habits, and even
415:which lived in the water, therefore making
4140:
3965:
3742:
3479:
3466:
3147:
3134:
3013:
3002:
2937:
2928:
2873:
2850:
2836:
2828:
1247:individuals, based on the "Tambach lovers"
584:Many paleontologists were uncertain about
102:
20:
2777:
2759:
2631:
2505:
2195:
2177:
2013:(Kuhn 1933) with remarks to its ontogeny"
2007:Bratislava, Jozef Klembara (1995-03-01).
1177:is equally stout as the humerus, and the
560:since that name was published first, but
548:back in 1896, was likely synonymous with
1622:Williston, S.W. (1911). "Restoration of
1414:was probably not a quick-moving animal.
1238:
891:
857:Life restoration and size comparison of
779:
373:For the first half of the 20th century,
1572:
1521:has provided additional information on
1021:located behind (rather than below) the
884:(a natural, relations-based grouping).
2655:
2653:
2651:
2566:
2564:
2440:Geological Society of America Bulletin
2315:Sushkin, Peter P. (18 December 1925).
2253:
2251:
2249:
2247:
1389:As a whole, he found it unlikely that
564:(1928) objected, noting that the name
4270:Cisuralian tetrapods of North America
2479:
2477:
2391:
2389:
2387:
2385:
2283:
2281:
2245:
2243:
2241:
2239:
2237:
2235:
2233:
2231:
2229:
2227:
2002:
2000:
1998:
1942:
1940:
1938:
1936:
1934:
1886:
1884:
1882:
1880:
1703:
1701:
1678:, the most primitive known reptile".
1669:
1667:
1665:
1578:
1576:
1458:Some authors have argued in favor of
828:. The Tambach Formation has produced
486:(hence the name of the type species,
7:
1878:
1876:
1874:
1872:
1870:
1868:
1866:
1864:
1862:
1860:
1816:
1814:
1812:
1810:
1808:
1806:
1804:
1773:
1771:
1769:
1767:
1765:
1733:
1731:
1729:
1727:
1617:
1615:
1613:
1611:
1595:Muséum National d'Histoire Naturelle
1099:is fairly short, with a total of 24
963:) than in any other seymouriamorph.
2064:Journal of Systematic Palaeontology
990:. The pineal foramen is smaller in
796:A block of sediment containing six
788:specimen first described by Berman
453:Early history as a putative reptile
2535:Canadian Journal of Earth Sciences
2302:10.1111/j.1096-3642.1922.tb02151.x
1897:Journal of Vertebrate Paleontology
1831:Canadian Journal of Earth Sciences
1692:10.1111/j.1096-3642.1918.tb02098.x
1583:Laurin, Michel (January 1, 1996).
1251:Some authors have argued that the
474:were first found near the town of
117:National Museum of Natural History
14:
1626:Broili, an American Cotylosaur".
1513:evidence from specimens found in
1271:which is more similar to that of
1152:was narrowest at mid-length. The
536:Likewise, English paleontologist
4085:
4079:
4074:
4069:
4064:
4057:
2398:"Review of the Labyrinthodontia"
1738:Vaughn, Peter Paul (May 1966). "
955:occipital flanges is greater in
624:. Some seymouriamorphs, such as
612:However, indirect evidence that
399:, which was a close relative of
330:features—so many, in fact, that
127:
16:Extinct genus of tetrapodomorphs
2396:Romer, Alfred Sherwood (1947).
1778:Laurin, Michel (13 July 1996).
1306:, which is more rectangular in
994:than in other seymouriamorphs.
784:A cast of the "Tambach lovers"
4265:Cisuralian tetrapods of Europe
668:Additional species and fossils
1:
4275:Fossil taxa described in 1904
2494:Annals of the Carnegie Museum
2296:. 1922:pt.1-2 (2): 455–460.
592:, which were unquestionably "
580:Proposed amphibian affinities
2986:Reptiliomorpha / Pan-Amniota
2017:Paläontologische Zeitschrift
1318:is more unique and derived.
544:, a dubious genera named by
511:formally named and described
1674:Watson, D.M.S. (1918). "On
1294:. Conversely, specimens of
1259:were smaller than those of
1200:Differences between species
1027:anterior semicircular canal
841:, assisting comparisons to
800:skeletons was found in the
692:described an assortment of
4291:
2131:10.1038/s41586-024-07572-0
1708:Broili, Ferdinand (1904).
1417:Although White considered
1126:pectoral (shoulder) girdle
521:. American paleontologist
4098:
4054:
3745:
3482:
3150:
3133:
3016:
3001:
2982:
2940:
2927:
2872:
2670:Annals of Carnegie Museum
2581:Annals of Carnegie Museum
2360:10.1017/S0016756800073593
2084:10.1017/S1477201906002008
1506:Histology and development
1073:internal carotid arteries
322:(in a biological sense),
266:
259:
216:
211:
124:Scientific classification
122:
110:
101:
23:
1590:Tree of Life Web Project
1263:, but some specimens of
1243:Life restoration of two
896:Diagrams of skulls from
765:on the Eastern coast of
761:in Permian sediments at
517:, and are now stored in
1744:Journal of Paleontology
1368:Milwaukee Public Museum
1337:are more triangular in
527:Desmospondylus anomalus
278:Desmospondylus anomalus
2729:10.1098/rstb.1992.0060
2664:Seymouria sanjuanensis
2575:Seymouria sanjuanensis
1953:The Journal of Geology
1893:Seymouria sanjuanensis
1825:Seymouria sanjuanensis
1628:The Journal of Geology
1484:Seymouria sanjuanensis
1370:
1248:
1245:Seymouria sanjuanensis
1209:Seymouria sanjuanensis
1146:entepicondylar foramen
1092:
905:
861:
816:, when they described
793:
786:Seymouria sanjuanensis
706:Seymouria sanjuanensis
685:
682:Seymouria sanjuanensis
467:
461:Outdated depiction of
424:is still an important
352:Seymouria sanjuanensis
340:Seymouria sanjuanensis
29:Temporal range: Early
4232:Paleobiology Database
2486:"First occurrence of
2262:Seymouria baylorensis
1782:Seymouria baylorensis
1624:Seymouria baylorensis
1468:Seymouria baylorensis
1361:
1242:
1205:Seymouria baylorensis
1089:Seymouria baylorensis
1086:
1015:Seymouria baylorensis
895:
859:Seymouria baylorensis
856:
783:
710:Seymouria baylorensis
680:block containing six
675:
620:as part of the group
503:Seymouria baylorensis
488:Seymouria baylorensis
460:
350:. On the other hand,
336:Seymouria baylorensis
318:. Although they were
113:Seymouria baylorensis
2518:– via Biostor.
2258:White, T.E. (1939).
1079:Postcranial skeleton
763:Prince Edward Island
736:, was reassigned by
342:. The type species,
2721:1992RSPTB.336..259S
2547:1999CaJES..36.1257S
2453:2001GSAB..113.1229R
2352:1942GeoM...79...81W
2340:Geological Magazine
2123:2024Natur.631..577M
2076:2007JSPal...5...69R
2029:1995PalZ...69..265B
1965:1928JG.....36..248R
1843:1987CaJES..24.1769B
1640:1911JG.....19..232W
1502:laid eggs on land.
1341:and rectangular in
812:remains outside of
730:Chickasha Formation
546:Edward Drinker Cope
540:noted in 1918 that
426:transitional fossil
393:were discovered in
3814:Opisthodontosaurus
3442:possibly includes
2761:10.7717/peerj.8698
2633:10.1111/pala.12448
2470:on March 11, 2012.
2426:(September 2001).
2288:Broom, R. (1922).
2179:10.7717/peerj.5565
2037:10.1007/BF02985990
1371:
1269:quadratojugal bone
1249:
1093:
914:intertemporal bone
906:
862:
794:
686:
574:evolutionary grade
468:
270:Conodectes favosus
4247:
4246:
4219:Open Tree of Life
4146:Taxon identifiers
4137:
4136:
4094:
4093:
4052:
4051:
4048:
4047:
4044:
4043:
3951:
3950:
3591:Protorothyrididae
3581:
3580:
3572:Stephanospondylus
3454:
3453:
3303:
3302:
2997:
2996:
2993:
2992:
2978:
2977:
2715:(1227): 259–273.
2117:(8021): 577–582.
1714:Palaeontographica
1460:sexual dimorphism
1454:Sexual dimorphism
1439:Tambach Formation
1158:olecranon process
1058:epipterygoid bone
822:Tambach Formation
820:fossils from the
755:Seymouria grandis
690:Peter Paul Vaughn
676:A replica of the
607:Theodore E. White
364:Tambach Formation
288:
287:
282:
274:
253:
242:
231:
207:
115:displayed at the
4282:
4240:
4239:
4227:
4226:
4214:
4213:
4201:
4200:
4188:
4187:
4186:
4173:
4172:
4171:
4141:
4104:Labyrinthodontia
4089:
4083:
4078:
4073:
4068:
4062:
4061:
4013:
4009:
3977:
3973:
3966:
3962:
3942:Tramuntanasaurus
3844:Rhiodenticulatus
3822:Protocaptorhinus
3743:
3736:
3662:
3588:
3551:Kuwavaatakdectes
3480:
3472:
3467:
3351:Karpinskiosaurus
3310:
3148:
3140:
3135:
3120:
3109:
3098:
3087:
3076:
3065:
3055:
3044:
3033:
3022:
3014:
3003:
2938:
2929:
2922:
2921:
2874:
2866:
2862:
2852:
2845:
2838:
2829:
2792:
2791:
2781:
2763:
2739:
2733:
2732:
2700:
2694:
2693:
2657:
2646:
2645:
2635:
2611:
2605:
2604:
2568:
2559:
2558:
2541:(8): 1257–1266.
2526:
2520:
2519:
2509:
2507:10.5962/p.226648
2481:
2472:
2471:
2469:
2463:. Archived from
2447:(9): 1229–1233.
2436:
2424:Reisz, Robert R.
2416:
2410:
2409:
2393:
2380:
2379:
2335:
2329:
2328:
2312:
2306:
2305:
2285:
2276:
2275:
2255:
2222:
2216:
2210:
2209:
2199:
2181:
2157:
2151:
2150:
2102:
2096:
2095:
2055:
2049:
2048:
2004:
1993:
1992:
1944:
1929:
1928:
1888:
1855:
1854:
1837:(9): 1769–1784.
1818:
1799:
1798:
1788:
1775:
1760:
1759:
1735:
1722:
1721:
1705:
1696:
1695:
1686:(3–4): 267–301.
1671:
1660:
1659:
1619:
1606:
1605:
1603:
1601:
1580:
1531:medullary cavity
1304:postorbital bone
1226:postfrontal bone
1097:vertebral column
802:Cutler Formation
722:Seymouria agilis
698:Organ Rock Shale
696:skulls from the
678:Cutler Formation
515:Ferdinand Broili
356:Cutler Formation
280:
272:
251:
247:
240:
236:
225:
221:
205:
198:
185:
172:
132:
131:
106:
96:
21:
4290:
4289:
4285:
4284:
4283:
4281:
4280:
4279:
4260:Seymouriamorphs
4250:
4249:
4248:
4243:
4235:
4230:
4222:
4217:
4209:
4204:
4196:
4191:
4182:
4181:
4176:
4167:
4166:
4161:
4148:
4138:
4133:
4090:
4056:
4040:
4011:
4007:
4000:
3975:
3971:
3960:
3959:
3947:
3878:
3800:Labidosauriscus
3729:
3709:Petrolacosaurus
3655:
3601:Anthracodromeus
3577:
3501:
3463:
3450:
3419:
3312:Seymouriamorpha
3299:
3236:Chroniosuchidae
3230:
3161:
3129:
3123:Gephyrostegidae
3079:Solenodonsaurus
3010:
2989:
2974:
2954:
2948:Tetrapodomorpha
2933:Tetrapodomorpha
2923:
2879:
2878:
2868:
2864:
2860:
2859:Reptiliomorpha
2856:
2801:
2796:
2795:
2741:
2740:
2736:
2702:
2701:
2697:
2659:
2658:
2649:
2613:
2612:
2608:
2570:
2569:
2562:
2555:10.1139/e99-035
2528:
2527:
2523:
2483:
2482:
2475:
2467:
2434:
2418:
2417:
2413:
2395:
2394:
2383:
2337:
2336:
2332:
2314:
2313:
2309:
2287:
2286:
2279:
2257:
2256:
2225:
2217:
2213:
2159:
2158:
2154:
2104:
2103:
2099:
2057:
2056:
2052:
2006:
2005:
1996:
1946:
1945:
1932:
1890:
1889:
1858:
1851:10.1139/e87-169
1820:
1819:
1802:
1786:
1777:
1776:
1763:
1737:
1736:
1725:
1707:
1706:
1699:
1673:
1672:
1663:
1621:
1620:
1609:
1599:
1597:
1582:
1581:
1574:
1569:
1508:
1456:
1446:adaptations in
1356:
1351:
1343:S. sanjuanensis
1327:S. sanjuanensis
1312:S. sanjuanensis
1300:S. sanjuanensis
1296:S. sanjuanensis
1281:S. sanjuanensis
1277:S. sanjuanensis
1265:S. sanjuanensis
1261:S. sanjuanensis
1222:S. sanjuanensis
1218:S. sanjuanensis
1202:
1081:
1050:pterygoid bones
1019:cochlear recess
916:, which is the
902:S. sanjuanensis
890:
851:
834:S. sanjuanensis
818:S. sanjuanensis
798:S. sanjuanensis
742:Robert R. Reisz
720:. For example,
718:S. sanjuanensis
670:
622:Seymouriamorpha
582:
455:
450:
405:Seymouriamorpha
379:Paleontologists
306:from the Early
281:Williston, 1910
238:S. sanjuanensis
204:
196:
183:
174:Seymouriamorpha
170:
126:
97:
95:
94:
89:
84:
79:
74:
69:
64:
59:
54:
49:
44:
39:
33:
27:
17:
12:
11:
5:
4288:
4286:
4278:
4277:
4272:
4267:
4262:
4252:
4251:
4245:
4244:
4242:
4241:
4228:
4215:
4202:
4189:
4174:
4158:
4156:
4150:
4149:
4144:
4135:
4134:
4132:
4131:
4126:
4121:
4119:Batrachosauria
4116:
4114:Anthracosauria
4111:
4106:
4099:
4096:
4095:
4092:
4091:
4055:
4053:
4050:
4049:
4046:
4045:
4042:
4041:
4039:
4038:
4037:
4036:
4026:
4017:
4015:
4002:
4001:
3999:
3998:
3997:
3996:
3990:
3981:
3979:
3963:
3953:
3952:
3949:
3948:
3946:
3945:
3938:
3931:
3924:
3917:
3914:Labidosaurikos
3910:
3903:
3896:
3888:
3886:
3884:Moradisaurinae
3880:
3879:
3877:
3876:
3869:
3862:
3854:
3847:
3840:
3833:
3825:
3818:
3810:
3803:
3796:
3789:
3786:Gecatogomphius
3782:
3775:
3768:
3765:Captorhinoides
3761:
3754:
3746:
3740:
3731:
3730:
3728:
3727:
3720:
3712:
3705:
3698:
3695:Halgaitosaurus
3691:
3683:
3676:
3668:
3666:
3657:
3656:
3654:
3653:
3650:Thuringothyris
3646:
3639:
3632:
3625:
3618:
3611:
3604:
3596:
3594:
3583:
3582:
3579:
3578:
3576:
3575:
3568:
3561:
3554:
3547:
3540:
3533:
3526:
3519:
3511:
3509:
3503:
3502:
3500:
3499:
3492:
3483:
3477:
3474:Diadectomorpha
3464:
3459:
3456:
3455:
3452:
3451:
3449:
3448:
3447:
3446:
3440:
3431:
3429:
3421:
3420:
3418:
3417:
3410:
3403:
3396:
3389:
3382:
3375:
3368:
3361:
3354:
3347:
3339:
3336:Discosauriscus
3332:
3325:
3322:Ariekanerpeton
3317:
3315:
3305:
3304:
3301:
3300:
3298:
3297:
3290:
3283:
3276:
3273:Madygenerpeton
3269:
3262:
3255:
3248:
3240:
3238:
3232:
3231:
3229:
3228:
3221:
3214:
3207:
3204:Hassiacoscutum
3200:
3193:
3186:
3179:
3171:
3169:
3167:Bystrowianidae
3163:
3162:
3160:
3159:
3151:
3145:
3131:
3130:
3128:
3127:
3116:
3105:
3094:
3083:
3072:
3061:
3051:
3040:
3029:
3017:
3011:
3008:Reptiliomorpha
3006:
2999:
2998:
2995:
2994:
2991:
2990:
2983:
2980:
2979:
2976:
2975:
2973:
2972:
2971:
2970:
2964:
2962:
2960:Reptiliomorpha
2956:
2955:
2953:
2952:
2951:
2950:
2941:
2935:
2925:
2924:
2920:
2919:
2910:
2901:
2892:
2886:
2877:
2870:
2869:
2857:
2855:
2854:
2847:
2840:
2832:
2826:
2825:
2817:
2812:
2807:
2800:
2799:External links
2797:
2794:
2793:
2734:
2695:
2676:(4): 217–225.
2647:
2606:
2560:
2521:
2473:
2420:Laurin, Michel
2411:
2381:
2330:
2307:
2277:
2260:"Osteology of
2223:
2211:
2152:
2097:
2050:
2023:(1): 265–281.
2011:Discosauriscus
1994:
1973:10.1086/623510
1959:(3): 248–260.
1930:
1903:(2): 253–268.
1856:
1800:
1761:
1750:(3): 603–612.
1723:
1697:
1661:
1648:10.1086/621840
1634:(3): 232–237.
1607:
1571:
1570:
1568:
1565:
1557:Discosauriscus
1548:Trimerorhachis
1527:lissamphibians
1515:Richards Spurs
1507:
1504:
1455:
1452:
1355:
1352:
1350:
1347:
1339:S. baylorensis
1335:ectopterygoids
1331:S. baylorensis
1323:S. baylorensis
1316:S. baylorensis
1308:S. baylorensis
1292:S. baylorensis
1273:S. baylorensis
1257:S. baylorensis
1234:S. baylorensis
1214:S. baylorensis
1201:
1198:
1080:
1077:
1031:supraoccipital
984:parietal bones
961:S. baylorensis
959:(particularly
940:squamosal bone
898:S. baylorensis
889:
886:
874:diadectomorphs
850:
847:
843:Discosauriscus
830:S. sanjuanensi
759:S. baylorensis
669:
666:
649:Discosauriscus
594:labyrinthodont
581:
578:
523:S.W. Williston
492:C.H. Sternberg
454:
451:
449:
446:
396:Discosauriscus
344:S. baylorensis
304:seymouriamorph
286:
285:
284:
283:
275:
264:
263:
257:
256:
255:
254:
243:
232:
226:Broili, 1904 (
223:S. baylorensis
214:
213:
209:
208:
194:
190:
189:
181:
177:
176:
168:
164:
163:
158:
154:
153:
148:
144:
143:
138:
134:
133:
120:
119:
108:
107:
99:
98:
90:
85:
80:
75:
70:
65:
60:
55:
50:
45:
40:
35:
34:
28:
15:
13:
10:
9:
6:
4:
3:
2:
4287:
4276:
4273:
4271:
4268:
4266:
4263:
4261:
4258:
4257:
4255:
4238:
4233:
4229:
4225:
4220:
4216:
4212:
4207:
4203:
4199:
4194:
4190:
4185:
4179:
4175:
4170:
4164:
4160:
4159:
4157:
4155:
4151:
4147:
4142:
4130:
4127:
4125:
4122:
4120:
4117:
4115:
4112:
4110:
4107:
4105:
4101:
4100:
4097:
4088:
4084:
4082:
4077:
4072:
4067:
4060:
4035:
4031:
4027:
4025:
4021:
4020:
4019:
4018:
4016:
4014:
4003:
3995:
3991:
3989:
3985:
3984:
3983:
3982:
3980:
3978:
3967:
3964:
3961:(crown group)
3958:
3954:
3944:
3943:
3939:
3937:
3936:
3932:
3930:
3929:
3925:
3923:
3922:
3918:
3916:
3915:
3911:
3909:
3908:
3904:
3902:
3901:
3900:Captorhinikos
3897:
3895:
3894:
3893:Balearosaurus
3890:
3889:
3887:
3885:
3881:
3875:
3874:
3870:
3868:
3867:
3863:
3860:
3859:
3855:
3853:
3852:
3851:Rhodotheratus
3848:
3846:
3845:
3841:
3839:
3838:
3834:
3831:
3830:
3826:
3824:
3823:
3819:
3816:
3815:
3811:
3809:
3808:
3804:
3802:
3801:
3797:
3795:
3794:
3790:
3788:
3787:
3783:
3781:
3780:
3776:
3774:
3773:
3769:
3767:
3766:
3762:
3760:
3759:
3755:
3753:
3752:
3748:
3747:
3744:
3741:
3739:
3738:Captorhinidae
3732:
3726:
3725:
3721:
3718:
3717:
3716:Spinoaequalis
3713:
3711:
3710:
3706:
3704:
3703:
3702:Kadaliosaurus
3699:
3697:
3696:
3692:
3689:
3688:
3684:
3682:
3681:
3677:
3675:
3674:
3670:
3669:
3667:
3665:
3664:Araeoscelidia
3658:
3652:
3651:
3647:
3645:
3644:
3643:Protorothyris
3640:
3638:
3637:
3633:
3631:
3630:
3626:
3624:
3623:
3619:
3617:
3616:
3615:Cephalerpeton
3612:
3610:
3609:
3605:
3603:
3602:
3598:
3597:
3595:
3592:
3584:
3574:
3573:
3569:
3567:
3566:
3565:Phanerosaurus
3562:
3560:
3559:
3555:
3553:
3552:
3548:
3546:
3545:
3541:
3539:
3538:
3534:
3532:
3531:
3527:
3525:
3524:
3520:
3518:
3517:
3513:
3512:
3510:
3508:
3504:
3498:
3497:
3493:
3490:
3489:
3485:
3484:
3481:
3478:
3475:
3468:
3465:
3462:
3457:
3445:
3441:
3439:
3435:
3434:
3433:
3432:
3430:
3427:
3422:
3416:
3415:
3411:
3409:
3408:
3404:
3402:
3401:
3400:Spinarerpeton
3397:
3395:
3394:
3390:
3388:
3387:
3383:
3381:
3380:
3376:
3374:
3373:
3369:
3367:
3366:
3362:
3360:
3359:
3355:
3353:
3352:
3348:
3345:
3344:
3340:
3338:
3337:
3333:
3331:
3330:
3326:
3324:
3323:
3319:
3318:
3316:
3313:
3306:
3296:
3295:
3291:
3289:
3288:
3284:
3282:
3281:
3280:Phratochronis
3277:
3275:
3274:
3270:
3268:
3267:
3263:
3261:
3260:
3256:
3254:
3253:
3252:Chroniosuchus
3249:
3247:
3246:
3245:Chroniosaurus
3242:
3241:
3239:
3237:
3233:
3227:
3226:
3222:
3220:
3219:
3215:
3213:
3212:
3211:Jiyuanitectum
3208:
3206:
3205:
3201:
3199:
3198:
3194:
3192:
3191:
3187:
3185:
3184:
3180:
3178:
3177:
3173:
3172:
3170:
3168:
3164:
3158:
3157:
3153:
3152:
3149:
3146:
3143:
3142:Chroniosuchia
3136:
3132:
3125:
3124:
3117:
3114:
3113:
3106:
3103:
3102:
3095:
3092:
3091:
3090:Termonerpeton
3084:
3081:
3080:
3073:
3070:
3069:
3068:Silvanerpeton
3062:
3060:
3059:
3052:
3049:
3048:
3041:
3038:
3037:
3030:
3027:
3026:
3019:
3018:
3015:
3012:
3009:
3004:
3000:
2988:
2987:
2981:
2968:
2967:
2966:
2965:
2963:
2961:
2957:
2949:
2945:
2944:
2943:
2942:
2939:
2936:
2934:
2930:
2926:
2918:
2914:
2911:
2909:
2908:Sarcopterygii
2905:
2902:
2900:
2896:
2893:
2891:
2887:
2885:
2881:
2880:
2875:
2871:
2867:
2853:
2848:
2846:
2841:
2839:
2834:
2833:
2830:
2824:
2823:
2818:
2816:
2813:
2811:
2808:
2806:
2803:
2802:
2798:
2789:
2785:
2780:
2775:
2771:
2767:
2762:
2757:
2753:
2749:
2745:
2738:
2735:
2730:
2726:
2722:
2718:
2714:
2710:
2706:
2699:
2696:
2691:
2687:
2683:
2679:
2675:
2671:
2667:
2665:
2656:
2654:
2652:
2648:
2643:
2639:
2634:
2629:
2625:
2621:
2620:Palaeontology
2617:
2610:
2607:
2602:
2598:
2594:
2590:
2586:
2582:
2578:
2576:
2567:
2565:
2561:
2556:
2552:
2548:
2544:
2540:
2536:
2532:
2525:
2522:
2517:
2513:
2508:
2503:
2499:
2495:
2491:
2489:
2480:
2478:
2474:
2466:
2462:
2458:
2454:
2450:
2446:
2442:
2441:
2433:
2431:
2428:"The reptile
2425:
2421:
2415:
2412:
2407:
2403:
2399:
2392:
2390:
2388:
2386:
2382:
2377:
2373:
2369:
2365:
2361:
2357:
2353:
2349:
2346:(2): 81–116.
2345:
2341:
2334:
2331:
2326:
2322:
2318:
2311:
2308:
2303:
2299:
2295:
2291:
2284:
2282:
2278:
2274:(5): 323–409.
2273:
2269:
2265:
2263:
2254:
2252:
2250:
2248:
2246:
2244:
2242:
2240:
2238:
2236:
2234:
2232:
2230:
2228:
2224:
2221:
2215:
2212:
2207:
2203:
2198:
2193:
2189:
2185:
2180:
2175:
2171:
2167:
2163:
2156:
2153:
2148:
2144:
2140:
2136:
2132:
2128:
2124:
2120:
2116:
2112:
2108:
2101:
2098:
2093:
2089:
2085:
2081:
2077:
2073:
2070:(1): 69–122.
2069:
2065:
2061:
2054:
2051:
2046:
2042:
2038:
2034:
2030:
2026:
2022:
2018:
2014:
2012:
2003:
2001:
1999:
1995:
1990:
1986:
1982:
1978:
1974:
1970:
1966:
1962:
1958:
1954:
1950:
1943:
1941:
1939:
1937:
1935:
1931:
1926:
1922:
1918:
1914:
1910:
1906:
1902:
1898:
1894:
1887:
1885:
1883:
1881:
1879:
1877:
1875:
1873:
1871:
1869:
1867:
1865:
1863:
1861:
1857:
1852:
1848:
1844:
1840:
1836:
1832:
1828:
1826:
1817:
1815:
1813:
1811:
1809:
1807:
1805:
1801:
1796:
1792:
1785:
1783:
1774:
1772:
1770:
1768:
1766:
1762:
1757:
1753:
1749:
1745:
1741:
1734:
1732:
1730:
1728:
1724:
1719:
1715:
1711:
1704:
1702:
1698:
1693:
1689:
1685:
1681:
1677:
1670:
1668:
1666:
1662:
1657:
1653:
1649:
1645:
1641:
1637:
1633:
1629:
1625:
1618:
1616:
1614:
1612:
1608:
1596:
1592:
1591:
1586:
1579:
1577:
1573:
1566:
1564:
1562:
1558:
1554:
1550:
1549:
1544:
1543:
1538:
1537:
1532:
1528:
1524:
1520:
1516:
1512:
1505:
1503:
1501:
1497:
1493:
1487:
1485:
1481:
1477:
1473:
1469:
1465:
1461:
1453:
1451:
1449:
1444:
1440:
1436:
1432:
1428:
1424:
1420:
1415:
1413:
1409:
1404:
1398:
1396:
1392:
1386:
1384:
1380:
1376:
1369:
1366:model at the
1365:
1360:
1353:
1348:
1346:
1344:
1340:
1336:
1332:
1328:
1324:
1319:
1317:
1313:
1309:
1305:
1301:
1297:
1293:
1289:
1288:lacrimal bone
1284:
1282:
1278:
1274:
1270:
1266:
1262:
1258:
1254:
1253:postparietals
1246:
1241:
1237:
1235:
1231:
1230:parietal bone
1228:contacts the
1227:
1223:
1219:
1215:
1210:
1206:
1199:
1197:
1195:
1190:
1188:
1184:
1180:
1176:
1171:
1165:
1163:
1159:
1155:
1151:
1147:
1143:
1139:
1138:interclavicle
1135:
1131:
1127:
1122:
1120:
1115:
1111:
1107:
1102:
1098:
1090:
1085:
1078:
1076:
1074:
1070:
1068:
1061:
1059:
1055:
1051:
1047:
1043:
1039:
1034:
1032:
1028:
1024:
1020:
1016:
1012:
1008:
1007:quadrate bone
1004:
1000:
995:
993:
989:
985:
981:
977:
973:
969:
964:
962:
958:
953:
949:
948:supratemporal
945:
941:
937:
933:
929:
925:
924:
919:
918:plesiomorphic
915:
911:
903:
899:
894:
887:
885:
883:
879:
875:
871:
866:
860:
855:
848:
846:
844:
840:
835:
831:
827:
823:
819:
815:
814:North America
811:
807:
803:
799:
791:
787:
782:
778:
776:
775:Richards Spur
772:
768:
764:
760:
756:
752:
751:
747:
743:
739:
738:Michel Laurin
735:
731:
727:
723:
719:
715:
714:Paul E. Olson
711:
707:
703:
699:
695:
691:
683:
679:
674:
667:
665:
663:
659:
655:
651:
650:
645:
644:Zdeněk Špinar
641:
637:
633:
629:
628:
623:
619:
615:
610:
608:
604:
603:Peter Sushkin
599:
595:
591:
587:
579:
577:
575:
571:
567:
563:
559:
555:
551:
547:
543:
539:
538:D.M.S. Watson
534:
532:
528:
524:
520:
516:
512:
508:
504:
499:
497:
493:
489:
485:
481:
480:Baylor County
477:
473:
464:
459:
452:
447:
445:
443:
439:
435:
431:
427:
423:
418:
414:
410:
406:
403:in the group
402:
398:
397:
392:
388:
384:
380:
376:
371:
369:
365:
361:
357:
353:
349:
345:
341:
337:
333:
329:
325:
321:
317:
313:
312:North America
309:
305:
301:
298:
294:
293:
279:
276:
271:
268:
267:
265:
262:
258:
250:
244:
239:
233:
229:
224:
218:
217:
215:
210:
203:
202:
195:
192:
191:
188:
182:
179:
178:
175:
169:
166:
165:
162:
159:
156:
155:
152:
149:
146:
145:
142:
139:
136:
135:
130:
125:
121:
118:
114:
109:
105:
100:
93:
88:
83:
78:
73:
68:
63:
58:
53:
48:
43:
38:
32:
26:
22:
19:
4153:
4124:Cotylosauria
4109:Lepospondyli
4063:
4010:Pan‑Reptilia
3974:Pan‑Mammalia
3940:
3935:Sumidadectes
3933:
3928:Rothianiscus
3926:
3921:Moradisaurus
3919:
3912:
3905:
3898:
3891:
3871:
3864:
3856:
3849:
3842:
3837:Reiszorhinus
3835:
3829:Puercosaurus
3827:
3820:
3812:
3807:Labidosaurus
3805:
3798:
3791:
3784:
3777:
3770:
3763:
3758:Baeotherates
3756:
3749:
3722:
3714:
3707:
3700:
3693:
3685:
3678:
3673:Aphelosaurus
3671:
3648:
3641:
3634:
3627:
3620:
3613:
3606:
3599:
3570:
3563:
3556:
3549:
3544:Diasparactus
3542:
3535:
3528:
3521:
3516:Alveusdectes
3514:
3494:
3486:
3444:Lissamphibia
3412:
3405:
3398:
3392:
3391:
3384:
3377:
3370:
3363:
3356:
3349:
3341:
3334:
3327:
3320:
3292:
3285:
3278:
3271:
3264:
3257:
3250:
3243:
3225:Yumenerpeton
3223:
3216:
3209:
3202:
3195:
3190:Bystrowiella
3188:
3181:
3174:
3154:
3121:
3110:
3101:Westlothiana
3099:
3088:
3077:
3066:
3056:
3045:
3034:
3025:Caerorhachis
3023:
2984:
2912:
2903:
2899:Osteichthyes
2894:
2821:
2751:
2747:
2737:
2712:
2708:
2698:
2673:
2669:
2663:
2623:
2619:
2609:
2587:(1): 53–72.
2584:
2580:
2574:
2538:
2534:
2530:
2524:
2500:(1): 63–79.
2497:
2493:
2487:
2465:the original
2444:
2438:
2429:
2414:
2405:
2401:
2343:
2339:
2333:
2324:
2320:
2310:
2293:
2271:
2267:
2261:
2214:
2169:
2165:
2155:
2114:
2110:
2100:
2067:
2063:
2053:
2020:
2016:
2010:
1956:
1952:
1948:
1900:
1896:
1892:
1834:
1830:
1824:
1794:
1790:
1781:
1747:
1743:
1739:
1717:
1713:
1683:
1679:
1675:
1631:
1627:
1623:
1600:February 24,
1598:. Retrieved
1588:
1560:
1556:
1552:
1546:
1540:
1534:
1522:
1511:Histological
1509:
1499:
1495:
1491:
1488:
1483:
1479:
1467:
1463:
1462:existing in
1457:
1447:
1442:
1434:
1430:
1427:crocodilians
1422:
1418:
1416:
1411:
1407:
1402:
1399:
1394:
1390:
1387:
1378:
1374:
1372:
1363:
1349:Paleobiology
1342:
1338:
1330:
1326:
1322:
1320:
1315:
1311:
1307:
1299:
1295:
1291:
1285:
1280:
1276:
1275:rather than
1272:
1264:
1260:
1256:
1250:
1244:
1233:
1221:
1217:
1213:
1208:
1204:
1203:
1191:
1166:
1123:
1118:
1106:zygapophyses
1094:
1088:
1067:Megalichthys
1065:
1062:
1053:
1035:
1014:
1010:
996:
991:
988:parietal eye
979:
976:lateral line
971:
965:
960:
956:
921:
909:
907:
901:
897:
878:parareptiles
870:captorhinids
864:
863:
858:
842:
838:
833:
829:
817:
809:
797:
795:
789:
785:
770:
758:
754:
748:
721:
717:
709:
705:
693:
687:
681:
657:
654:larval stage
647:
639:
631:
625:
617:
613:
611:
597:
585:
583:
569:
565:
562:Alfred Romer
557:
554:Robert Broom
549:
541:
535:
530:
526:
506:
502:
500:
498:until 1930.
495:
487:
471:
469:
462:
441:
421:
416:
413:larval stage
408:
400:
394:
386:
383:captorhinids
374:
372:
351:
343:
339:
335:
331:
323:
291:
290:
289:
277:
269:
248:
241:Vaughn, 1966
237:
222:
206:Broili, 1904
200:
199:
187:Seymouriidae
186:
112:
111:A fossil of
24:
18:
4178:Wikispecies
4006:Sauropsida
3907:Gansurhinus
3873:Saurorictus
3779:Euconcordia
3772:Captorhinus
3724:Zarcasaurus
3680:Araeoscelis
3636:Paleothyris
3622:Coelostegus
3507:Diadectidae
3488:Limnoscelis
3438:Microsauria
3426:Microsauria
3386:Nyctiboetus
3294:Uralerpeton
3259:Ingentidens
3197:Dromotectum
3183:Bystrowiana
2863:Pan‑Amniota
2626:: 131–154.
2408:(1): 7–368.
1585:"Seymouria"
1542:Rhinesuchus
932:captorhinid
928:embolomeres
849:Description
746:parareptile
590:embolomeres
470:Fossils of
432:(reptiles,
252:Olson, 1979
4254:Categories
4129:Eureptilia
4102:See also:
4024:Sauropsida
3970:Synapsida
3858:Riabininus
3687:Dictybolos
3530:Desmatodon
3414:Waggoneria
3365:Leptoropha
3218:Synesuchus
3112:Embolomeri
3058:Romeriscus
2969:see below↓
2430:Macroleter
2327:: 179–181.
1797:(1): 1–16.
1567:References
1441:preserved
1385:membrane.
1025:, and its
1017:retains a
936:otic notch
923:Ventastega
806:New Mexico
750:Macroleter
558:Conodectes
542:Conodectes
360:New Mexico
320:amphibians
273:Cope, 1896
249:S. grandis
4184:Seymouria
4154:Seymouria
4028:includes
3992:includes
3988:Synapsida
3751:Acrodenta
3629:Hylonomus
3537:Diadectes
3393:Seymouria
3379:Microphon
3372:Makowskia
3358:Kotlassia
3343:Enosuchus
3287:Suchonica
3266:Jarilinus
3176:Axitectum
3156:Laosuchus
3047:Eldeceeon
3036:Casineria
2917:Tetrapoda
2882:Kingdom:
2822:Seymouria
2770:2167-8359
2754:: e8698.
2642:1475-4983
2531:Seymouria
2488:Seymouria
2376:131417438
2368:1469-5081
2188:2167-8359
2172:: e5565.
2139:1476-4687
2092:1477-2019
1989:129513686
1949:Seymouria
1925:130445307
1791:PaleoBios
1740:Seymouria
1676:Seymouria
1656:140644621
1593:. Paris:
1561:Seymouria
1553:Seymouria
1523:Seymouria
1500:Seymouria
1496:Seymouria
1492:Seymouria
1480:Seymouria
1464:Seymouria
1448:Seymouria
1443:Seymouria
1431:Seymouria
1423:Seymouria
1412:Seymouria
1408:Seymouria
1403:Seymouria
1395:Seymouria
1391:Seymouria
1379:Seymouria
1375:Seymouria
1364:Seymouria
1354:Lifestyle
1119:Seymouria
1101:vertebrae
1054:Seymouria
1023:vestibule
1011:Seymouria
992:Seymouria
980:Seymouria
972:Seymouria
957:Seymouria
910:Seymouria
865:Seymouria
839:Seymouria
810:Seymouria
771:Seymouria
753:in 2001.
728:from the
694:Seymouria
688:In 1966,
658:Seymouria
640:Seymouria
632:Seymouria
627:Kotlassia
618:Seymouria
614:Seymouria
609:in 1939.
598:Seymouria
586:Seymouria
570:Seymouria
566:Seymouria
550:Seymouria
531:Seymouria
507:Seymouria
496:Seymouria
472:Seymouria
463:Seymouria
442:Seymouria
422:Seymouria
417:Seymouria
409:Seymouria
401:Seymouria
387:Seymouria
375:Seymouria
332:Seymouria
328:reptilian
324:Seymouria
292:Seymouria
201:Seymouria
147:Kingdom:
141:Eukaryota
25:Seymouria
4163:Wikidata
4030:reptiles
3793:Kahneria
3608:Brouffia
3558:Orobates
3496:Tseajaia
3407:Utegenia
3329:Biarmica
2890:Chordata
2888:Phylum:
2884:Animalia
2788:32195050
2690:85794721
2601:86217084
2516:91262105
2206:30631641
2147:38961286
2045:87658588
1981:30060526
1536:Acheloma
1519:Oklahoma
1472:chevrons
1419:Seymoria
1216:than in
1194:chevrons
1134:coracoid
1003:tympanum
734:Oklahoma
726:skeleton
662:amniotes
430:amniotes
411:) had a
391:tadpoles
261:Synonyms
212:Species
180:Family:
161:Chordata
157:Phylum:
151:Animalia
137:Domain:
4224:4948517
4211:1308618
4198:3241196
4169:Q131455
3994:mammals
3957:Amniota
3866:Romeria
3523:Ambedus
3461:Amniota
2779:7069408
2717:Bibcode
2666:Vaughn"
2543:Bibcode
2449:Bibcode
2348:Bibcode
2264:Broili"
2197:6322490
2119:Bibcode
2072:Bibcode
2025:Bibcode
1961:Bibcode
1917:4524091
1839:Bibcode
1756:1301745
1720:: 1–48.
1636:Bibcode
1476:turtles
1142:humerus
1130:scapula
1046:choanae
952:tabular
946:of the
944:flanges
826:Germany
744:to the
476:Seymour
448:History
434:mammals
368:Germany
308:Permian
297:extinct
193:Genus:
167:Order:
31:Permian
2786:
2776:
2768:
2688:
2640:
2599:
2514:
2374:
2366:
2204:
2194:
2186:
2145:
2137:
2111:Nature
2090:
2043:
1987:
1979:
1923:
1915:
1754:
1654:
1529:, the
1383:amnion
1224:, the
1187:tarsus
1183:fibula
1162:carpus
1150:radius
1148:. The
1038:palate
999:stapes
968:orbits
876:, and
792:(2000)
790:et al.
767:Canada
636:Watson
519:Munich
436:, and
316:Europe
295:is an
4237:37223
4206:IRMNG
4034:birds
2913:Clade
2904:Clade
2895:Clade
2748:PeerJ
2686:S2CID
2597:S2CID
2512:S2CID
2468:(PDF)
2435:(PDF)
2372:S2CID
2166:PeerJ
2041:S2CID
1985:S2CID
1977:JSTOR
1921:S2CID
1913:JSTOR
1787:(PDF)
1752:JSTOR
1652:S2CID
1435:et al
1325:. In
1179:tibia
1175:femur
1170:ilium
1110:atlas
1042:vomer
888:Skull
882:clade
484:Texas
478:, in
466:1930s
438:birds
348:Texas
300:genus
4193:GBIF
4032:and
4022:see
3986:see
3436:see
2946:see
2784:PMID
2766:ISSN
2638:ISSN
2364:ISSN
2202:PMID
2184:ISSN
2143:PMID
2135:ISSN
2088:ISSN
1602:2018
1545:and
1470:had
1207:and
1181:and
1154:ulna
1132:and
1124:The
1114:axis
1095:The
1036:The
997:The
950:and
926:and
900:and
740:and
702:Utah
509:was
338:and
314:and
228:type
37:PreꞒ
2774:PMC
2756:doi
2725:doi
2713:336
2678:doi
2628:doi
2589:doi
2551:doi
2502:doi
2457:doi
2445:113
2356:doi
2298:doi
2192:PMC
2174:doi
2127:doi
2115:631
2080:doi
2033:doi
1969:doi
1905:doi
1847:doi
1688:doi
1644:doi
1255:of
824:of
804:of
732:of
700:of
366:of
358:of
310:of
302:of
4256::
4234::
4221::
4208::
4195::
4180::
4165::
3428:"?
2915::
2906::
2897::
2782:.
2772:.
2764:.
2750:.
2746:.
2723:.
2711:.
2707:.
2684:.
2674:74
2672:.
2668:.
2650:^
2636:.
2624:63
2622:.
2618:.
2595:.
2585:76
2583:.
2579:.
2563:^
2549:.
2539:36
2537:.
2510:.
2498:62
2496:.
2492:.
2476:^
2455:.
2443:.
2437:.
2422:;
2406:99
2404:.
2400:.
2384:^
2370:.
2362:.
2354:.
2344:79
2342:.
2323:.
2319:.
2292:.
2280:^
2272:85
2270:.
2266:.
2226:^
2200:.
2190:.
2182:.
2168:.
2164:.
2141:.
2133:.
2125:.
2113:.
2109:.
2086:.
2078:.
2066:.
2062:.
2039:.
2031:.
2021:69
2019:.
2015:.
1997:^
1983:.
1975:.
1967:.
1957:36
1955:.
1933:^
1919:.
1911:.
1901:20
1899:.
1859:^
1845:.
1835:24
1833:.
1829:.
1803:^
1795:17
1793:.
1789:.
1764:^
1748:40
1746:.
1726:^
1718:51
1716:.
1712:.
1700:^
1684:88
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1650:.
1642:.
1632:19
1630:.
1610:^
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1551:.
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1450:.
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552:.
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482:,
87:Pg
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2758::
2752:8
2731:.
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2304:.
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2176::
2170:6
2149:.
2129::
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2074::
2068:5
2047:.
2035::
2027::
1991:.
1971::
1963::
1927:.
1907::
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1758:.
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1690::
1658:.
1646::
1638::
1604:.
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246:†
235:†
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220:†
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92:N
82:K
77:J
72:T
67:P
62:C
57:D
52:S
47:O
42:Ꞓ
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