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Paleogeographic map of the Late Triassic world with Trilophosaurus and Malerisaurus robinsonae localities highlighted.
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The holotype of Malerisaurus langstoni from the Late Triassic (Otischalkian) Trilophosaurus quarry 2 of West Texas is a chimera. The holotype represents at least 6-7 individuals of four reptilian groups: Trilophosauridae, Rhynchosauridae, Parasuchidae and Aetosauria. The majority of the material, including all of the cranial fragments, are re-ident...
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... considerably larger than the dorsal vertebrae ( Fig. 3H-I), especially the anterior dorsals (Fig. 3H), which are approximately half the length of the cervical vertebrae. This difference in size suggests that the axial skeleton of the holotype is derived from more than one individual. The cervical vertebrae, "vertebrae 2-7" of Chatterjee (1986, fig. 5), have a consistent overall size and are probably from a single individual. The two dorsal vertebral series (the anterior series is vertebrae 10-13 and the posterior series is vertebrae 1925 of Chatterjee, 1986, fig. 5) show slight differences in size, which may represent either variation within the dorsal series or indicate that they ...
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... skeleton of the holotype is derived from more than one individual. The cervical vertebrae, "vertebrae 2-7" of Chatterjee (1986, fig. 5), have a consistent overall size and are probably from a single individual. The two dorsal vertebral series (the anterior series is vertebrae 10-13 and the posterior series is vertebrae 1925 of Chatterjee, 1986, fig. 5) show slight differences in size, which may represent either variation within the dorsal series or indicate that they are from two different individuals. The sacral and caudal vertebrae appear consistent in size with the posterior dorsal series and likely all originated from the same individual. The anterior series of dorsal vertebrae ...
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... which may represent either variation within the dorsal series or indicate that they are from two different individuals. The sacral and caudal vertebrae appear consistent in size with the posterior dorsal series and likely all originated from the same individual. The anterior series of dorsal vertebrae (Fig. 3H) is illustrated by Chatterjee (1986, fig. 5) as consisting of four com- plete vertebrae, but when we examined the holotype this series of verte- brae consisted of three nearly complete vertebrae all with portions of their neural spines missing and a partial centrum attached to the poste- rior end of the series. Chatterjee (1986) illustrated the posterior series of dorsal ...
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... when we examined the holotype this series of verte- brae consisted of three nearly complete vertebrae all with portions of their neural spines missing and a partial centrum attached to the poste- rior end of the series. Chatterjee (1986) illustrated the posterior series of dorsal vertebrae as unobstructed in left lateral view (Chatterjee, 1986, fig. 5), however, a number of ribs have been crushed dorsally into the sides of the posterior four vertebrae of this series, totally obscuring them in left lateral view (Fig. ...
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... they both possess extensive transverse processes that have concave dorsal surfaces. The caudal series is assigned to T. buettneri based on: elongate cylindrical centra of the vertebrae with no ventral keel; and in the distal caudals, the prezygapophyses extending directly from the centrum with no discernable neural arch. Also, Chatterjee (1986, fig. 5) illustrated what he considered the 37 th vertebra, with the anterior end facing towards the right side of the page; this is not corrected in Figure 3M in order to show the exact orientation of the specimen as illustrated by Chatterjee ...
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... This feature is quite rare among Permo-Triassic tetrapods and is only possessed by Trilophosaurus and Araeoscelis. If the holotype of M. robinsonae does indeed represent a partial skeleton of Trilophosaurus, then the paleogeo- graphic distribution of Trilophosaurus would change from a fairly en- demic distribution in the American Southwest ( Fig. 5; Heckert et al., 2006) to a nearly Pangean distribution. Also, this would provide the potential for a stronger correlation between the Maleri Formation of India and the Chinle Group of the American Southwest (Fig. 5), espe- cially since it has been determined that isolated Trilophosaurus teeth can be identified to the species level ...
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... the paleogeo- graphic distribution of Trilophosaurus would change from a fairly en- demic distribution in the American Southwest ( Fig. 5; Heckert et al., 2006) to a nearly Pangean distribution. Also, this would provide the potential for a stronger correlation between the Maleri Formation of India and the Chinle Group of the American Southwest (Fig. 5), espe- cially since it has been determined that isolated Trilophosaurus teeth can be identified to the species level (Heckert et al., ...
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Citations
... The last eight decades have seen a very productive period for the history of dinosaur research in India, and numerous dinosaur clades of Triassic and Jurassic ages have been identified in the Maleri, Dharmaram and Kota formations of the Pranhita-Godavari valley (e.g. Huene 1940;Colbert 1958;Jain et al. 1964Jain et al. , 1975Jain et al. , 1979Roy-Chowdhury 1965;Kutty 1969;Chatterjee 1967Chatterjee , 1974Chatterjee , 1978Chatterjee , 1980Chatterjee , 1982Chatterjee , 1987Chatterjee and Roy-Chowdhury 1974;Yadagiri 1982;Jain and Roy-Chowdhury 1987;Yadagiri and Rao 1987;Yadagiri et al. 1979;Yadagiri 1988Yadagiri , 2001Kutty et al. 1987Kutty et al. , 2007Kutty and Sengupta 1989;Chatterjee and Creisler 1994;Bandyopadhyay and Roy-Chowdhury 1996;Loyal et al. 1996;Bandyopadhyay 1999;Nath et al. 2002;Bandyopadhyay and Sengupta 2006;Spielmann et al. 2006;Bandyopadhyay et al. 2002Bandyopadhyay et al. , 2010Novas et al. 2010Novas et al. , 2011Kammerer et al. 2016;Chatterjee et al. 2017; Galton 2019; Chatterjee 2020; Bandyopadhyay and Ray 2020; Prasad and Parmar 2020; Khosla and Bajpai 2021). Middle Jurassic dinosaurs have also been discovered in western peninsular India (Figure 1). ...
... Lucas 2020), the rhynchosaur Paradepedon, the phytosaur Parasuchus, the archosaur 'Malerisaurus,' an aetosaur, the theropod dinosaur Alwalkeria, a prosauropod, a large dicynodont, and the cynodont Exaeretodon (e.g. Huene 1940;Jain et al. 1964;Roy-Chowdhury 1965;Chatterjee 1967Chatterjee , 1974Chatterjee , 1978Chatterjee , 1980Chatterjee , 1982Chatterjee , 1987Chatterjee and Roy-Chowdhury 1974;Jain and Roy-Chowdhury 1987;Chatterjee and Creisler 1994;Bandyopadhyay and Sengupta 2006;Spielmann et al. 2006;Kammerer et al. 2016). This is the only well-described Upper Triassic tetrapod assemblage from the Pranhita-Godavari Valley. ...
We review the record of Late Triassic and Jurassic dinosaurs from India to determine their geological ages
and palaeobiogeographic significance. The oldest Indian dinosaur, the basal saurischian Alwalkeria maleriensis,
is from the early Late Triassic (Otischalkian/Carnian) lower Maleri Formation. The archosaur-dominated
Upper Maleri Formation (Adamanian/late Carnian?) contains two sauropodomorph clades. The Indian
Jurassic record of dinosaurs from the Pranhita-Godavari Valley is more extensive but has poor age constraints,
whereas fragmentary, and better dated dinosaur remains are known from the Early Middle Jurassic
of Kachchh, Gujarat and Rajasthan. The Indian Late Triassic dinosaurs fit into a picture of some degree of
dinosaur cosmopolitanism across Late Triassic Pangaea, with primitive saurischians and/or theropods and
primitive sauropodomorphs found in eastern Gondwana (India), western Gondwana (South America) and
Euramerica. The well-known non-neosauropods Kotasaurus and Barapasaurus from the Middle Jurassic Kota
Formation provide substantial evidence that India was a major centre of the early evolution of neosauropods.
Tharosaurus indicus, from the Middle Jurassic strata of the Jaisalmer Basin, is a relic of a lineage that
likely originated in India and swiftly expanded throughout the rest of Pangaea. This lineage further stresses
the significance of Gondwanan India in elucidating the origin and early evolutionary history of neosauropod
dinosaurs.
... Another specimen from the Tecovas Member, lower Dockum Formation of western Texas, US, (Carnian to early Norian, early Late Triassic) was recognized as representing a taxon that was very closely related to Malerisaurus robinsonae and assigned to the new species Malerisaurus langstoni (Chatterjee, 1986). However, this holotype and only known specimen is actually composed of elements belonging to several diapsid taxa, most notably Trilophosaurus buettneri (Spielmann et al., 2006). Therefore, "Malerisaurus langstoni" is no longer considered a valid taxon. ...
... Therefore, "Malerisaurus langstoni" is no longer considered a valid taxon. Furthermore, the validity of the Indian Malerisaurus robinsonae was questioned, as this taxon also showed distinct similarities to Trilophosaurus buettneri (Spielmann et al., 2006). Following the original interpretation by Chatterjee (1980; of Malerisaurus robinsonae as a "protorosaur" closely related to Protorosaurus speneri, it has been incorporated in several phylogenetic analyses (Benton, 1985;Benton & Allen, 1997;Evans, 1988;Jalil, 1997;Rieppel, Fraser & Nosotti, 2003). ...
The historical clade “Protorosauria” represents an important group of archosauromorph reptiles that had a wide geographic distribution between the Late Permian and Late Triassic. “Protorosaurs” are characterized by their long necks, which are epitomized in the genus Tanystropheus and in Dinocephalosaurus orientalis . Recent phylogenetic analyses have indicated that “Protorosauria” is a polyphyletic clade, but the exact relationships of the various “protorosaur” taxa within the archosauromorph lineage is currently uncertain. Several taxa, although represented by relatively complete material, have previously not been assessed phylogenetically. We present a new phylogenetic hypothesis that comprises a wide range of archosauromorphs, including the most exhaustive sample of “protorosaurs” to date and several “protorosaur” taxa from the eastern Tethys margin that have not been included in any previous analysis. The polyphyly of “Protorosauria” is confirmed and therefore we suggest the usage of this term should be abandoned. Tanystropheidae is recovered as a monophyletic group and the Chinese taxa Dinocephalosaurus orientalis and Pectodens zhenyuensis form a new archosauromorph clade, Dinocephalosauridae, which is closely related to Tanystropheidae. The well-known crocopod and former “protorosaur” Prolacerta broomi is considerably less closely related to Archosauriformes than was previously considered.
... A striking example of this issue is the discovery that some members of Avemetatarsalia such as Asilisaurus Nesbitt et al., 2010 andTeleocrater Charig, 1956 possessed a crocodylian-like tarsus, a character that was tradition- ally used to separate avemetatarsalians and pseudosu- chians ( Nesbitt et al. 2010Nesbitt et al. , 2017a. Other key recent studies regarding the anatomy of Late Triassic reptiles include expanded understanding of the phylogenetic relationships and stratigraphic occurrences of the ar- chosauriform Vancleavea campi Long and Murry, 1995(Parker and Barton 2008, Nesbitt et al. 2009a), the first definitive records of tanystropheids from western North America ( Pritchard et al. 2015), the discovery of three- dimensionally preserved drepanosaurids ( Pritchard et al. 2016), and the recognition of a diversity of allokotosaurid archosauromorphs other than Trilophosaurus Case, 1928(Spielmann et al. 2006, Spielmann et al. 2009, Flynn et al. 2010, Nesbitt et al. 2015, 2017b, Marsh et al. 2017). ...
... The lowest known occurrence of a leptosuchomorph phytosaur (sensu Stocker 2010) is a skull (TTU-P09234) referred to Leptosuchus Case, 1922 Figure 1. Relative stratigraphic (A) and geographic (B) locations of fossil localities (adapted from Heckert et al. 2006, Martz 2008, Mueller et al. 2016, Sarig?l, 2016, 2017a, 2017b, and Kent et al. 2017. Asterisks indicate localities with described specimens. ...
... The distal condyles in the specimens are otherwise equal in size (Fig. 5N, P, R, T), a character state not present in Petrolacosaurus kansensis, but shared by in distal view because there is a groove on the posterior surface of the femur separating the fibular condyle and the crista tibiofibularis (less noticeable in TTU-P11286 and TTU-P11409E because of lack of preservation) (Fig. 5P, R). This posterior groove, for articulation for the tibia, is present in Malerisaurus spp., Trilophosaurus buettneri, and Azendohsaurus madagaskarensis and overall, the character distributions of these specimens are consistent with allokotosaurids (Chatterjee 1980, Chatterjee 1986b, Spielmann et al. 2006, 2007, 2008, 2009, Nesbitt et al. 2015). Based on the morphology and expansion of the distal articular surface, we assign these specimens to the clade that includes Allokotosauria, Prolacerta broomi, and Archosauriformes. ...
... Unlike previous analyses 26 , we did not include data from Cosesaurus, Kadimakara and Trachelosaurus because the material is poorly preserved and yields few characters useful for phylogenetic analysis. We also excluded Malerisaurus because its species may be chimaeras 41 . Vallesaurus was added to the new data matrix since it provides some information about the cranial morphology of drepanosaurs, which is lacking in the previous analysis 26 . ...
Live birth has evolved many times independently in vertebrates, such as mammals and diverse groups of lizards and snakes. However, live birth is unknown in the major clade Archosauromorpha, a group that first evolved some 260 million years ago and is represented today by birds and crocodilians. Here we report the discovery of a pregnant long-necked marine reptile (Dinocephalosaurus) from the Middle Triassic (∼245 million years ago) of southwest China showing live birth in archosauromorphs. Our discovery pushes back evidence of reproductive biology in the clade by roughly 50 million years, and shows that there is no fundamental reason that archosauromorphs could not achieve live birth. Our phylogenetic models indicate that Dinocephalosaurus determined the sex of their offspring by sex chromosomes rather than by environmental temperature like crocodilians. Our results provide crucial evidence for genotypic sex determination facilitating land-water transitions in amniotes.
... Recently, Spielmann et al. (2006) claimed that the holotype of Malerisaurus langstoni (TMM 31099-11; Chatterjee 1986b) is a chimera composed of trilophosaur, aetosaur, phytosaur, and rhynchosaur material. However, Spielmann et al. (2006) based their referral of particular elements on non-diagnostic plesiomorphies found in a variety of archosauromorphs, and their reinterpretation of these elements has other puzzling aspects (e.g. the element they identified as a Trilophosaurus prefrontal is a pterygoid with clear alveoli, SJN and NF pers. ...
... Recently, Spielmann et al. (2006) claimed that the holotype of Malerisaurus langstoni (TMM 31099-11; Chatterjee 1986b) is a chimera composed of trilophosaur, aetosaur, phytosaur, and rhynchosaur material. However, Spielmann et al. (2006) based their referral of particular elements on non-diagnostic plesiomorphies found in a variety of archosauromorphs, and their reinterpretation of these elements has other puzzling aspects (e.g. the element they identified as a Trilophosaurus prefrontal is a pterygoid with clear alveoli, SJN and NF pers. obs.). ...
... Recently, Spielmann et al. (2006) claimed that the holotype of Malerisaurus langstoni (TMM 31099-11; Chatterjee 1986b) is a chimera composed of trilophosaur, aetosaur, phytosaur, and rhynchosaur material. However, Spielmann et al. (2006) based their referral of particular elements on non-diagnostic plesiomorphies found in a variety of archosauromorphs, and their reinterpretation of these elements has other puzzling aspects (e.g. the element they identified as a Trilophosaurus prefrontal is a pterygoid with clear alveoli, SJN and NF pers. ...
... Recently, Spielmann et al. (2006) claimed that the holotype of Malerisaurus langstoni (TMM 31099-11; Chatterjee 1986b) is a chimera composed of trilophosaur, aetosaur, phytosaur, and rhynchosaur material. However, Spielmann et al. (2006) based their referral of particular elements on non-diagnostic plesiomorphies found in a variety of archosauromorphs, and their reinterpretation of these elements has other puzzling aspects (e.g. the element they identified as a Trilophosaurus prefrontal is a pterygoid with clear alveoli, SJN and NF pers. obs.). ...
The Post Quarry, within the lower part of the type section of the Upper Triassic Cooper Canyon Formation in southern Garza County, western Texas, contains a remarkably diverse vertebrate assemblage. The Post Quarry has produced: the small temnospondyl Rileymillerus cosgriffi; the metoposaurid Apachesaurus gregorii; possible dicynodonts and eucynodonts; a clevosaurid sphenodontian; non-archosauriform archosauromorphs (Trilophosaurus dornorum, simiosaurians, and possibly Malerisaurus); the phytosaur Leptosuchus; several aetosaurs (Calyptosuchus wellesi, Typothorax coccinarum, Paratypothorax, and Desmatosuchus smalli); the poposauroid Shuvosaurus inexpectatus (“Chatterjeea elegans”); the rauisuchid Postosuchus kirkpatricki; an early crocodylomorph; several dinosauromorphs (the lagerpetid Dromomeron gregorii, the silesaurid Technosaurus smalli, a herrerasaurid, and an early neotheropod); and several enigmatic small diapsids. Revised lithostratigraphic correlations of the lower Cooper Canyon Formation with the Tecovas Formation, the occurrence of Leptosuchus, and the overall composition of the assemblage indicate that the Post Quarry falls within the Adamanian biozone, and not the Revueltian biozone. Stratigraphic subdivision of the Adamanian biozone may be possible, and the Post Quarry may be correlative with the upper part of the Adamanian biozone in Arizona. The age of the Post Quarry assemblage is possibly late Lacian or earliest Alaunian (late early Norian or earliest middle Norian), between 220 and 215 Ma.
... reviewed the fauna, which is from the Colorado City Formation of the Chinle Group. The following taxa are present: the amphibians Latiscopus, Buettneria and Apachesaurus, a procolophonid, the rhynchosaur Otischalkia, the archosaurs Doswellia, Trilophosaurus (¼ Malerisaurus) and Poposaurus, the aetosaurs Longosuchus (¼ Lucasuchus) and Coahomasuchus, and the phytosaurs Parasuchus and Angistorhinus Long & Murry 1995;Spielmann et al. 2006c). ...
... Massospondylus' of Kutty & Sengupta 1989), a large dicynodont, and the cynodont Exeraetodon (e.g. Huene 1940;Jain et al. 1964;Roychowdhury 1965;Chatterjee 1967Chatterjee , 1974Chatterjee , 1978Chatterjee , 1980aChatterjee , 1982Chatterjee , 1987Chatterjee & Roychowdhury 1974;Jain & Roychowdhury 1987;Bandyopadhyay & Sengupta 2006;Spielmann et al. 2006c). This is the only welldescribed Upper Triassic tetrapod assemblage from the Pranhita-Godavari Valley. ...
The Triassic timescale based on nonmarine tetrapod biostratigraphy and biochronology divides Triassic time into eight land-vertebrate faunachrons (LVFs) with boundaries defined by the first appearance datums (FADs) of tetrapod genera or, in two cases, the FADs of a tetrapod species. Definition and characterization of these LVFs is updated here as follows: the beginning of the Lootsbergian LVF = FAD of Lystrosaurus; the beginning of the Nonesian = FAD Cynognathus; the beginning of the Perovkan LVF = FAD Eocyclotosaurus; the beginning of the Berdyankian LVF = FAD Mastodonsaurus giganteus; the beginning of the Otischalkian LVF = FAD Parasuchus; the beginning of the Adamanian LVF = FAD Rutiodon; the beginning of the Revueltian LVF = FAD Typothorax coccinarum; and the beginning of the Apachean LVF = FAD Redondasaurus. The end of the Apachean (= beginning of the Wasonian LVF, near the beginning of the Jurassic) is the FAD of the crocodylomorph Protosuchus. The Early Triassic tetrapod LVFs, Lootsbergian and Nonesian, have characteristic tetrapod assemblages in the Karoo basin of South Africa, the Lystrosaurus assemblage zone and the lower two-thirds of the Cynognathus assemblage zone, respectively. The Middle Triassic LVFs, Perovkan and Berdyankian, have characteristic assemblages from the Russian Ural foreland basin, the tetrapod assemblages of the Donguz and the Bukobay svitas, respectively. The Late Triassic LVFs, Otischalkian, Adamanian, Revueltian and Apachean, have characteristic assemblages in the Chinle basin of the western USA, the tetrapod assemblages of the Colorado City Formation of Texas, Blue Mesa Member of the Petrified Forest Formation in Arizona, and Bull Canyon and Redonda formations in New Mexico. Since the Triassic LVFs were introduced, several subdivisions have been proposed: Lootsbergian can be divided into three sub-LVFs, Nonesian into two, Adamanian into two and Revueltian into three. However, successful inter-regional correlation of most of these sub-LVFs remains to be demonstrated. Occasional records of nonmarine Triassic tetrapods in marine strata, palynostratigraphy, conchostracan biostratigraphy, magnetostratigraphy and radioisotopic ages provide some basis for correlation of the LVFs to the standard global chronostratigraphic scale. These data indicate that Lootsbergian = uppermost Changshingian, Induan and possibly earliest Olenekian; Nonesian = much of the Olenekian; Perovkan = most of the Anisian; Berdyankian = latest Anisian? and Ladinian; Otischalkian = early to late Carnian; Adamanian = most of the late Carnian; Revueltian = early-middle Norian; and Apachean = late Norian-Rhaetian. The Triassic timescale based on tetrapod biostratigraphy and biochronology remains a robust tool for the correlation of nonmarine Triassic tetrapod assemblages independent of the marine timescale.
... WILD (1973), CHATTERJEE (1980), SANZ & LOPEZ-MARTINEZ (1984), RENESTO (1994), JALIL (1997), andSEN (2003) gave only lateral views, or incomplete information, on the ilia in Tanystropheus, Malerisaurus, Cosesaurus, Magalancosaurus, Jesairosaurus, and Pamelaria respectively. The validity of Malerisaurus langstoni (CHATTERJEE 1986) has recently been questioned (SPIELMANN et al. 2006). The pelvis is absent from the specimen of Boreopricea, an Early Triassic "prolacertiform' from Arctic Russia (TATARINOV 1978, BENTON & ALLEN 1997), but FRASER & RIEPPEL (2006 recently published a new tanystropheid, Amotosaurus rotfeldensis, including a rough picture of a pelvis quite similar to that of Macrocnemus. ...
The biomechanical advantages of the pelvic structure are inspected in terms of the relative position of the iliosacral joint with respect to the acetabulum. Disarticulated bone material from Lower Triassic karst deposits from Southern Poland provides a unique opportunity to study both sides of the ilium in several early diapsids. Extant squamate material provides a good reference source for this study, and permits the reconstruction of a scenario for iliac evolution in the two neodiapsid clades: Lepidosauromorpha and Archosauromorpha. Ancestrally, the iliosacral joint was probably dorsal and posterior to the acetabulum level. Facultative bipedality may evolve when the iliosacral joint is situated relatively close to the acetabulum, as is common in the Iguania. The more postero-dorsal position of the joint in many non-iguanians correlates with a tendency to limb reduction that develops in parallel in several subgroups. This divergence in locomotor adaptation may have been important in the divergence of the squamate clades. The ventral extension of the iliosacral joint, to overlap the medial side of the acetabulum, is considered a possible synapomorphy of the Archosauriformes, and a possible prerequisite for the obligatory bipedality that eventually evolved in crown group archosaurs. The inclusion of the last dorsal vertebra into the sacrum probably preceded this trend in archosauromorph phylogeny.
... The importance of these specimens is that both the Bull Canyon Formation and the Sonsela Member of the Petrified Forest Formation are Revueltian in age, so these records represent the only known records of T. jacobsi in the Revueltian and are thus the youngest substantiated occurrences of the taxon. Spielmann et al. (2006b) reinterpreted the holotype of Malerisaurus langstoni (from Trilophosaurus quarry 2), originally de scribed by Chatterjee (1986) as a protorosaur, as a chimera consisting principally of Trilophosaurus buettneri material. They restricted the holotype of M. langstoni to the skull fragments, which they synony mized with T. buettneri. ...
... They restricted the holotype of M. langstoni to the skull fragments, which they synony mized with T. buettneri. Interestingly, Spielmann et al. (2006b) noted that the other species of Malerisaurus, M. robinsonae, from the Maleri Formation of India, appears to have a femur with a large and extensive internal trochanter, a feature that is known elsewhere in the Late Triassic solely in Trilophosaurus. Thus, they concluded that the holotype of M. robinsonae, also named and described by Chatterjee (1980), may also include Trilophosaurus material. ...
... Most of the Trilophosaurus material from quarry 2 is postcrania with little or no association. The only exception to this is portions of the holotype of "Malerisaurus langstoni" (Spielmann et al., 2006b). ...
... The importance of these specimens is that both the Bull Canyon Formation and the Sonsela Member of the Petrified Forest Formation are Revueltian in age, so these records represent the only known records of T. jacobsi in the Revueltian and are thus the youngest occurrences of the taxon. Spielmann et al. (2006b) reinterpreted the holotype of Malerisaurus langstoni (from Trilophosaurus quarry 2), originally described by Chatterjee (1986) as a protorosaur, as a chimera consisting principally of Trilophosaurus buettneri material. They restricted the holotype of M. langstoni to the skull fragments, which they synonymized with T. buettneri. ...
... They restricted the holotype of M. langstoni to the skull fragments, which they synonymized with T. buettneri. Interestingly, Spielmann et al. (2006b) noted that the other species of Malerisaurus, M. robinsonae, from the Maleri Formation of India, appears to have a femur with a large and extensive internal trochanter, a feature that is known elsewhere in the Late Triassic solely in Trilophosaurus. Thus, they concluded that the holotype of M. robinsonae, also named and described by Chatterjee (1980), may also include Trilophosaurus material. ...
... Most of the Trilophosaurus material from quarry 2 is postcrania with little or no association. The only exception to this is portions of the holotype of "Malerisaurus langstoni" (Spielmann et al., 2006b). ...
Trilophosaurus is an aberrant archosauromorph from the Upper Triassic Chinle Group of the south-western United States. We review the history of study of Trilophosaurus, revise the diagnosis of the genus and both species of Trilophosaurus, T. buettneri Case and T. jacobsi Murry, and summarize its biostratigraphic record. Reevaluation of T. dornorum Mueller and Parker reveals no diagnostic differences between it and T. jacobsi, rendering T. dornorum a junior subjective synonym of T. jacobsi. The two species of Trilophosaurus have well established temporal ranges, with T. buettneri extending from the middle Otischalkian to late Adamanian and T. jacobsi extending from early Adamanian into the Revueltian.
