Rutiodon

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Rutiodon
Temporal range: 237–208.5  Ma
Rutiodon carolinensis.JPG
Skeleton of Rutiodon carolinensis (AMNH 1) in the American Museum of Natural History
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order:† Phytosauria
Family:† Parasuchidae
Subfamily:† Mystriosuchinae
Genus:† Rutiodon
Emmons, 1856
Species
  • †R. carolinensis(Emmons, 1856) (type)
  • †R. manhattanensis(Huene, 1913)
Synonyms
  • Palaeonornis
    Emmons, 1857

Rutiodon ("Wrinkle tooth") is an extinct genus of mystriosuchine phytosaurs from the Late Triassic of the eastern United States. [1] The type species of Rutiodon, Rutiodon carolinensis, encompasses a large number of skulls and assorted postcranial fossils discovered in the Cumnock Formation of North Carolina. Fossils referable to the species are also known from Pennsylvania, New Jersey, and Virginia. Rutiodon carolinensis is the most well-described species of phytosaur in eastern North America, though its validity as a natural taxon has been questioned. Some paleontologists also recognize a larger and more robust species, Rutiodon manhattanensis, which is known from teeth and postcranial fossils from New Jersey and Pennsylvania.

Contents

Description

Skeletal diagram of Rutiodon manhattanensis, with preserved portions of the skeleton in grey Rutiodon.jpg
Skeletal diagram of Rutiodon manhattanensis, with preserved portions of the skeleton in grey

Like other phytosaurs, Rutiodon strongly resembled a crocodile, but its nostrils were positioned far back on the head, close to the eyes, instead of at the tip of the snout. It had enlarged front teeth, and a relatively narrow jaw, somewhat resembling that of a modern gharial. This suggests that this carnivore probably caught fish and it may also have snatched land animals from the waterside. [2] Also, like modern crocodiles, its back, flanks, and tail were covered with bony armored plates. [3]

Rutiodon was among the largest carnivorous animals of its environment, measuring up to 8 metres (26 ft) long and weighing about 1 metric ton (1.1 short tons). [2] [4]

Species

R. carolinensis

Rutiodon fossil.jpg
Rutiodon BW.jpg
AMNH fossil (top) and life restoration (bottom) of Rutiodon carolinensis

The type species of Rutiodon is R. carolinensis. It was originally named by Ebenezer Emmons in 1856, based on fossils from the Deep River coal field (Cumnock Formation) [5] of North Carolina. The original fossils include five striated teeth and associated vertebrae, ribs, and interclavicle fragments. [5]

Later, Emmons (1860) mentioned that he had discovered a nearly complete skull of R. carolinensis from North Carolina, at the time the most complete phytosaur skull known from the United States. It is also the largest skull referred to Rutiodon, at a length of 77.3 cm (30.4 inches). [6] This skull was described in more detail by Edwin H. Colbert in 1947. [7] Emmons' phytosaur skull was originally stored in the Williams College geological museum, [5] [6] and was later transferred to the National Museum of Natural History (USNM). [8] Many skulls and partial skeletons of R. carolinensis have been discovered near Egypt, North Carolina, and are now housed and displayed at the American Museum of Natural History (AMNH). [5]

Skeletal mount of R. carolinensis (AMNH 1) viewed from the front Rutiodon carolinensis AMNH 1 anterior.jpg
Skeletal mount of R. carolinensis (AMNH 1) viewed from the front

In 1963, a small partial phytosaur skull (AMNH 5500) was discovered at the Granton Quarry of North Bergen, New Jersey. This skull, recovered from grey argillite of the Lockatong Formation, was described by Colbert in 1965. He identified the skull as a probable juvenile specimen of R. carolinensis. [6] Doyle and Sues (1995) described a well-preserved phytosaur skull (SMP VP-45) from the New Oxford Formation in York County, Pennsylvania. This skull was very similar to skulls previously referred to R. carolinesis. They considered R. carolinensis to be an undiagnostic species, as it was originally diagnosed based on teeth. According to these authors, "Rutiodon" is a metataxon of eastern phytosaurs for which monophyly cannot be established. [8]

Since its original description, R. carolinensis has been conflated with various other phytosaur species from the eastern United States. Isaac Lea named several phytosaur species from Pennsylvania shortly before Emmons' description: Clepsysaurus pennsylvanicus (in 1851) and Centemodon sulcatus (in 1856). Both species were compared favorably with R. carolinensis by Emmons, and some authors have noted that either could be considered a senior synonym of Rutiodon. Nevertheless, fossils of R. carolinensis are much more complete, so the validity of the genus is rarely questioned. Clepsysaurus and Centemodon are most commonly considered dubious and undiagnostic, and their fossils have variably been referred to Rutiodon, Phytosaurus , or Phytosauria incertae sedis by different authors. [5] [9] [6]

Othniel Charles Marsh (1893) named Belodon validus , based on a scapula from the New Haven Arkose near Simsbury, Connecticut. [10] In 1896, Marsh mentioned a phytosaur skull from Chatham County, North Carolina. This was the second phytosaur skull found in the area, after that of Emmons (1860). Marsh named his phytosaur skull Rhytidodon rostratus. Belodon validus is considered dubious and undiagnostic, [6] while "Rhytidodon rostratus" (specimen USNM 5373) has been referred to R. carolinensis. [5]

Phytosaur fossils tentatively referred to R. carolinensis were unearthed in 1959 in Fairfax County, Virginia, near Dulles International Airport which was still under construction. These fossils, including vertebrae, ribs, and scutes, were recovered from red calcareous mudstones of the Ball's Bluff Siltstone. This extends the range of Rutiodon (and phytosaurs as a whole) into the Culpeper Basin. [11]

R. manhattanensis

The holotype of R. manhattanensis on display in the American Museum of Natural History Rutiodon manhattanensis holotype.jpg
The holotype of R. manhattanensis on display in the American Museum of Natural History

Fossils of a second species, R. manhattanensis, were discovered in 1910 from "red sandy marl" (Stockton Formation) [6] [8] below the Palisades near Fort Lee, New Jersey. In 1913, it was described by Friedrich von Huene, who provided a new species name in reference to its close proximity to Manhattan. The fossil is a partially articulated posterior torso, including the hip, hind limbs (missing the feet), and portions of the tail and scutes. It was differentiated from R. carolinensis based on a proportionally larger tibia and more robust hip. R. manhattanensis is also noticeably larger in size: Huene remarked that the holotype has the largest femur he had ever observed in phytosaurs, at a length of 43-44 cm (17 inches). [12]

Some authors have referred R. manhattanensis to "Clepsysaurus" [5] or Phytosaurus, [9] but its referral to Rutiodon was upheld by Colbert (1965). [6] Very large phytosaur teeth, osteoderms, and hindlimb fossils (specimen YPM-PU 11544) from York, Pennsylvania have also been referred to R. manhattanensis. [6] [8] A few authors have doubted the validity of R. manhattanensis, arguing that the differences between the two species may be due to sexual dimorphism. [8]

Classification

The exact relationship between Rutiodon and other phytosaurs has gone through much revision. [9] [13]

Several papers in the late 20th century extended the scope of the genus Rutiodon, allowing it to encompass phytosaur species from both the eastern and western United States. Western species lumped into Rutiodon include nearly all species previously placed into the genera Leptosuchus , Machaeroprosopus , and Pseudopalatus . [5] [9] [14] A 1995 paper, and most subsequent studies on phytosaurs, disagreed with the idea that Rutiodon encompassed western phytosaur species. [15] The authors re-instated the validity of Machaeroprosopus (with Pseudopalatus as a junior synonym) and Leptosuchus. They also created the new genus Smilosuchus for "Machaeroprosopus" gregorii. [15]

Recent papers agree that Rutiodon occupies a tier of the phytosaur family tree more derived than Paleorhinus and less derived than Leptosuchus . [1] [16] [17] [13] In other words, Rutiodon lies within the large clade Phytosauridae [1] (alternatively known as Mystriosuchinae) [17] and outside the less inclusive clade Leptosuchomorpha. [1] A 2001 conference abstract argued that Rutiodon carolinensis was a synonym of Angistorhinus , [18] mirroring older suggestions that Angistorhinus was directly ancestral to Rutiodon. [9] This interpretation of synonymy has not been formally published. A 2018 analysis of phytosaur relationships did support a placement for Rutiodon carolinensis as the sister taxon of Angistorhinus in a clade at the base of Mystriosuchinae. [13] Later papers describing Volcanosuchus and Colossosuchus , two basal mystriosuchines from the Tiki Formation of India, did not support a sister group relationship between Angistorhinus and Rutiodon. Instead, Angistorhinus was consistently placed as sister to Brachysuchus . Rutiodon was usually recovered as closer to (but still outside) Leptosuchomorpha. [19] [20] Over half of the most parsimonious trees in the 2023 description of Colossosuchus positioned Rutiodon as the sister taxon to Volcanosuchus . [20]

Below is a cladogram from Stocker (2012): [16]

Phytosauria  

Related Research Articles

Phytosaurs are an extinct group of large, mostly semiaquatic Late Triassic archosauriform reptiles. Phytosaurs belong to the order Phytosauria. and are sometimes referred to as parasuchians. Phytosauria, Parasuchia, Parasuchidae, and Phytosauridae have often been considered equivalent groupings containing the same species. Some recent studies have offered a more nuanced approach, defining Parasuchidae and Phytosauridae as nested clades within Phytosauria as a whole. Phytosaurs were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodilians in size, appearance, and lifestyle, as an example of convergence or parallel evolution

<i>Hyperodapedon</i> Extinct genus of reptiles

Hyperodapedon is an extinct genus of rhynchosaur reptiles which lived during Late Triassic period. Like other rhynchosaurs, it was an heavily built archosauromorph, distantly related to archosaurs such as crocodilians and dinosaurs. Hyperodapedon in particular was part of the subfamily Hyperodapedontinae, a specialized rhynchosaurian subgroup with broad skulls, beaked snouts, and crushing tooth plates on the roof of the mouth.

<span class="mw-page-title-main">Pseudosuchia</span> Clade of reptiles

Pseudosuchia is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs". Despite Pseudosuchia meaning "false crocodiles", the name is a misnomer as true crocodilians are now defined as a subset of the group.

<i>Paleorhinus</i> Extinct genus of reptiles

Paleorhinus is an extinct genus of widespread basal phytosaur known from the Late Triassic. The genus was named in 1904 based on the type species Paleorhinus bransoni, which is known from Wyoming and Texas in the United States. Another valid species, Paleorhinus angustifrons from Bavaria, Germany, is also commonly referred to the genus. Paleorhinus had a length of about 2.5 meters.

<i>Parasuchus</i> Extinct genus of reptiles

Parasuchus is an extinct genus of basal phytosaur known from the Late Triassic of Andhra Pradesh and Madhya Pradesh, India. At its most restricted definition, Parasuchus contains a single species, Parasuchus hislopi. Parasuchus hislopi is one of several species belonging to a basal grade of phytosaurs, typified by the genus Paleorhinus. Historically, Paleorhinus has been known from better-described fossils, and many species have been lumped into that genus. Parasuchus hislopi, despite being described earlier than Paleorhinus, was considered an undiagnostic chimera until new neotype fossils were described in the late 1970s. Parasuchus hislopi and the two unambiguously valid species of Paleorhinus are all closely related; some authors have historically described them all under the species Paleorhinus, while others place the two Paleorhinus species into Parasuchus according to the principle of priority.

<i>Nicrosaurus</i> Extinct genus of reptiles

Nicrosaurus (/nɪkroʊˈsɔrəs/) is an extinct genus of phytosaur reptile existing during the Late Triassic period. Although it looked like a crocodile, it was not closely related to these creatures, instead being an example of parallel evolution. The main difference between Nicrosaurus and modern crocodiles is the position of the nostrils – Nicrosaurus's nostrils, or external nares, were placed directly in front of the forehead, whereas in crocodiles, the nostrils are positioned on the end of the snout. A 2013 study has also found that ilium of Nicrosaurus is quite distinctive from all other phytosaurs.

<i>Phytosaurus</i> Extinct genus of reptiles

Phytosaurus is a dubious genus of extinct parasuchid phytosaur found in an outcrop of the Keuper in Germany. Phytosaurus was the first phytosaur to be described, being done so by Georg Friedrich von Jaeger in 1828. The type species is P. cylindricodon and a second species, P. cubicodon, is also known.

Redondasaurus is an extinct genus or subgenus of phytosaur from the Late Triassic of the southwestern United States. It was named by Hunt & Lucas in 1993, and contains two species, R. gregorii and R. bermani. It is the youngest and most evolutionarily-advanced of the phytosaurs.

<i>Angistorhinus</i> Extinct genus of reptiles

Angistorhinus is an extinct genus of phytosaur known from the Late Triassic period of Texas and Wyoming, United States. It was first named by Mehl in 1913 and the type species is Angistorhinus grandis. Other species from Texas and Wyoming, A. alticephalus, A. gracilis and A. maximus, are cospecific with the type species. Angistorhinus is known from the holotype UC 631, partial skull and lower jaws recovered from the Popo Agie Formation, Chugwater Group, Wyoming and from the associated paratype UM 531, a partial skull, TMM 31098-1, skull and lower jaws and ROM 7977, partial skull and lower jaws, recovered from the 'Pre-Tecovas Horizon' in the Dockum Group, Texas. A possible second species, A. talainti is known from the Triassic of Morocco. In 1995, Long and Murry created the new combination, Angistorhinus megalodon by synonymy for Brachysuchus. Hungerbühler and Sues (2001) hypothesised that Angistorhinus is a junior synonym of Rutiodon. However, in 2010 Michelle R. Stocker retained the validity of Brachysuchus and of A. grandis.

Mystriosuchus is an extinct genus of phytosaur that lived in the Late Triassic in Europe and Greenland. It was first named by Eberhard Fraas in 1896, and includes four species: M. planirostris, M. westphali, M. steinbergeri, and M. alleroq.

<i>Smilosuchus</i> Extinct genus of reptiles

Smilosuchus is an extinct genus of leptosuchomorph parasuchid from the Late Triassic of North America.

<span class="mw-page-title-main">Mystriosuchini</span> Extinct tribe of reptiles

Mystriosuchini, historically known as Pseudopalatinae, is an extinct tribe of derived phytosaurs in the clade Leptosuchomorpha. As with all other phytosaurs, mystriosuchins lived during Late Triassic. The name is derived from the genus Mystriosuchus.

<i>Leptosuchus</i> Extinct genus of reptiles

Leptosuchus is an extinct genus of leptosuchomorph phytosaur with a complex taxonomical history. Fossils have been found from the Dockum Group and lower Chinle Formation outcropping in Texas, New Mexico, and Arizona, USA, and date back to the Carnian stage of the Late Triassic.

<i>Machaeroprosopus</i> Extinct genus of reptiles

Machaeroprosopus is an extinct genus of mystriosuchin leptosuchomorph phytosaur from the Late Triassic of the southwestern United States. M. validus, once thought to be the type species of Machaeroprosopus, was named in 1916 on the basis of three complete skulls from Chinle Formation, Arizona. The skulls have been lost since the 1950s, and a line drawing in the original 1916 description is the only visual record of the specimen. Another species, M. andersoni, was named in 1922 from New Mexico, and the species M. adamanensis, M. gregorii, M. lithodendrorum, M. tenuis, and M. zunii were named in 1930. Most species have been reassigned to the genera Smilosuchus, Rutiodon, or Phytosaurus. Until recently, M. validus was considered to be the only species that has not been reassigned. Thus, Machaeroprosopus was considered to be a nomen dubium or "doubtful name" because of the lack of diagnostic specimens that can support its distinction from other phytosaur genera. However, a taxonomic revision of Machaeroprosopus, conducted by Parker et al. in 2013, revealed that UW 3807, the holotype of M. validus, is not the holotype of Machaeroprosopus, while the species Machaeroprosopus buceros, Machaeroprosopus being a replacement name, with a fixed type species, for Metarhinus, is the combinatio nova of the type species of the genu: Belodon buceros. Therefore, the name Pseudopalatus must be considered a junior synonym of Machaeroprosopus, and all species of the former must be reassigned to the latter. This revised taxonomy was already accepted in several studies, including Stocker and Butler (2013). Stocker and Butler (2013) also treated M. andersoni as a valid species, and not a junior synonym of Machaeroprosopus buceros as was previously suggested by Long and Murry (1995).

Pravusuchus is an extinct genus of leptosuchomorph parasuchid phytosaur known from the Late Triassic of Arizona, United States. It contains a single species, Pravusuchus hortus, which is known from three specimens. These specimens were previously referred to Smilosuchus or to Leptosuchus, but Pravusuchus's autapomorphy, its phylogenetic position as well as a trait shared with mystriosuchins, justified the erection of a new taxon for the material.

<i>Brachysuchus</i> Extinct genus of reptiles

Brachysuchus is an extinct genus of phytosaur known from the late Triassic period of Dockum Group in Texas, United States. It is known from the holotype UMMP 10336 is composed of a skull, lower jaws and partial postcranium and from the associated paratype UMMP 14366, nearly complete skull, recovered from the 'Pre-Tecovas Horizon' in the Dockum Group. It was first named by Case in 1929 and the type species is Brachysuchus megalodon. Its closest relative was Angistorhinus. However, its rostral crest was much smaller than that of Angistorhinus, and the rostrum as a whole is shorter and thicker.

The Colorado City Formation is a Late Triassic geologic formation in the Dockum Group of Texas, United States. It has previously been known as the Iatan Member, Colorado City Member or 'Pre-Tecovas Horizon'.

<i>Colossosuchus</i> Genus of reptile

Colossosuchus is an extinct genus of large mystriosuchine phytosaur from the Upper Triassic Tiki Formation of India. It was among the largest known phytosaurs, reaching a length of over 8 m (26 ft). Among its characteristic features are the dome-shaped head and downturned tip of the upper jaw. Colossosuchus was part of an endemic radiation of phytosaurs from India, closely related to two additional forms not yet named. The genus is monotypic, only including the species Colossosuchus techniensis.

<i>Jupijkam</i> Genus of reptile

Jupijkam is an extinct genus of phytosaur from the Late Triassic of Nova Scotia, Canada. The genus is monotypic, including only the species Jupijkam paleofluvialis. It is based on a partial skull and a few other fragments from the White Water Member of the Blomidon Formation. Along with unnamed fossils from the Fleming Fjord Formation of Greenland, these remains represent the northernmost record of phytosaurs. Jupijkam is named after Jipijka'm, the great horned serpent of Mi'kmaq mythology.

References

  1. 1 2 3 4 Michelle R. Stocker (2010). "A new taxon of phytosaur (Archosauria: Pseudosuchia) from the Late Triassic (Norian) Sonsela Member (Chinle Formation) in Arizona, and a critical reevaluation of Leptosuchus Case, 1922". Palaeontology. 53 (5): 997–1022. doi: 10.1111/j.1475-4983.2010.00983.x .
  2. 1 2 Gaines, Richard M. (2001). Coelophysis. ABDO Publishing Company. p. 21. ISBN   1-57765-488-9.
  3. ↑ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 95. ISBN   1-84028-152-9.
  4. ↑ Hartman, Scott A.; Lovelace, David M.; Linzmeier, Benjamin J.; Mathewson, Paul D.; Porter, Warren P. (November 2022). "Mechanistic Thermal Modeling of Late Triassic Terrestrial Amniotes Predicts Biogeographic Distribution". Diversity. 14 (11): 973. doi: 10.3390/d14110973 . ISSN   1424-2818.
  5. 1 2 3 4 5 6 7 8 Gregory, Joseph T. (27 June 1962). "The Relationships of the American Phytosaur Rutiodon" (PDF). American Museum Novitates (2095): 1–22.
  6. 1 2 3 4 5 6 7 8 Colbert, Edwin H. (10 September 1965). "A Phytosaur from North Bergen, New Jersey" (PDF). American Museum Novitates (2230): 1–25.
  7. ↑ Colbert, Edwin Harris (1947). "Studies of the phytosaurs Machaeroprosopus and Rutiodon". Bulletin of the American Museum of Natural History. 88 (2). hdl:2246/395.
  8. 1 2 3 4 5 Doyle, Kevin D.; Sues, Hans-Dieter (1995-09-14). "Phytosaurs (Reptilia: Archosauria) from the Upper Triassic New Oxford Formation of York County, Pennsylvania". Journal of Vertebrate Paleontology. 15 (3): 545–553. doi:10.1080/02724634.1995.10011247. ISSN   0272-4634.
  9. 1 2 3 4 5 Gregory, J. T. (1962-11-01). "The genera of phytosaurs". American Journal of Science. 260 (9): 652–690. doi: 10.2475/ajs.260.9.652 . ISSN   0002-9599.
  10. ↑ Marsh, O.C. (1893). "Restoration of Anchisaurus". The American Journal of Science. Series 3 45: 169-170.
  11. ↑ Weems, Robert E. (16 November 1979). "A large parasuchian (phytosaur) from the Upper Triassic portion of the Culpeper Basin of Virginia (USA)". Proceedings of the Biological Society of Washington. 92 (4): 682–688.
  12. ↑ Huene, Friedrich R. (1913). "A new phytosaur from the Palisades near New York". Bulletin of the American Museum of Natural History. 32 (15). hdl:2246/1411.
  13. 1 2 3 Jones, Andrew S.; Butler, Richard J. (2018-12-10). "A new phylogenetic analysis of Phytosauria (Archosauria: Pseudosuchia) with the application of continuous and geometric morphometric character coding". PeerJ. 6: e5901. doi: 10.7717/peerj.5901 . ISSN   2167-8359. PMC   6292387 . PMID   30581656.
  14. ↑ Ballew, K. L. (1989). "A phylogenetic analysis of Phytosauria from the Late Triassic of the western United States". In: Lucas, S. G. and Hunt, A. P., eds., Dawn of the age of dinosaurs in the American Southwest, pp. 309-339. New Mexico Museum of Natural History. Albuquerque.
  15. 1 2 Long, R. A., and Murry, P. A. (1995). Late Triassic (Carnian and Norian) tetrapods from the southwestern United States. New Mexico Museum of Natural History and Science Bulletin4:1-254.
  16. 1 2 Stocker, M. R. (2012). "A new phytosaur (Archosauriformes, Phytosauria) from the Lot's Wife beds (Sonsela Member) within the Chinle Formation (Upper Triassic) of Petrified Forest National Park, Arizona". Journal of Vertebrate Paleontology. 32 (3): 573–586. doi:10.1080/02724634.2012.649815. S2CID   129527672.
  17. 1 2 Christian F. Kammerer; Richard J. Butler; Saswati Bandyopadhyay; Michelle R. Stocker (2016). "Relationships of the Indian phytosaur Parasuchus hislopi Lydekker, 1885" (PDF). Papers in Palaeontology. 2 (1): 1–23. doi:10.1002/spp2.1022. S2CID   83780331.
  18. ↑ Hungerbühler, A. and Sues, H.-D. (2001). Status and phylogenetic relationships of the Late Triassic phytosaur Rutiodon carolinensis. Journal of Vertebrate Paleontology21(3 suppl.):64A.
  19. ↑ Datta, Debajit; Ray, Sanghamitra; Bandyopadhyay, Saswati (2021). Smith, Andrew (ed.). "Cranial morphology of a new phytosaur (Diapsida, Archosauria) from the Upper Triassic of India: implications for phytosaur phylogeny and biostratigraphy". Papers in Palaeontology. 7 (2): 675–708. doi:10.1002/spp2.1292. ISSN   2056-2799. S2CID   213698017.
  20. 1 2 Datta, Debajit; Ray, Sanghamitra (2023). Field, Daniel (ed.). "A giant phytosaur (Diapsida, Archosauria) from the Upper Triassic of India with new insights on phytosaur migration, endemism and extinction". Papers in Palaeontology. 9 (1). doi:10.1002/spp2.1476. ISSN   2056-2799. S2CID   257103850.
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