Eudimorphodon

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Eudimorphodon
Temporal range: Late Triassic, 219–215  Ma
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Eudimorphodon.jpg
MCSNB 2888 in Bergamo
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Order: Pterosauria
Family: Eudimorphodontidae
Subfamily: Eudimorphodontinae
Genus: Eudimorphodon
Zambelli, 1973
Species:
E. ranzii
Binomial name
Eudimorphodon ranzii
Zambelli, 1973

Eudimorphodon was a pterosaur that was discovered in 1973 by Mario Pandolfi in the town of Cene, Italy and described the same year by Rocco Zambelli. The nearly complete skeleton was retrieved from shale deposited during the Late Triassic (mid to late Norian stage, [1] 219-215 million years ago), [2] making Eudimorphodon one of the oldest pterosaurs known. [3] It had a wingspan of about 100 centimeters (3.3 ft). [4] Eudimorphodon is known from several skeletons, including juvenile specimens.

Contents

Discovery and species

Fossil at Museo di Scienze Naturali, Bergamo, specimens MCSNB 8959 a,b Eudimorphodon ranzii Berbenno.JPG
Fossil at Museo di Scienze Naturali, Bergamo, specimens MCSNB 8959 a,b

Eudimorphodon currently includes one species, the type species Eudimorphodon ranzii, which was first described by Zambelli in 1973. It is based on holotype MCSNB 2888. The specific name honors Professor Silvio Ranzi. A second species, Eudimorphodon rosenfeldi, was named by Dalla Vecchia in 1995 for two specimens found in Italy. However, further study by Dalla Vecchia found that these actually represented a distinct genus, which he named Carniadactylus in 2009. [5] A third species is Eudimorphodon cromptonellus, described by Jenkins and colleagues in 2001. [6] It is based on a juvenile specimen with a wingspan of just 24 centimeters, MGUH VP 3393, found in the early nineties in Jameson Land, Greenland. Its specific name honors Professor Alfred Walter Crompton; the name is a diminutive because the exemplar is so small. In 2015 it was named as a separate genus Arcticodactylus by Alexander Kellner. [7] Specimen BSP 1994 I 51, in 2003 referred to a cf E. ranzii, [8] was in 2015 by Kellner made the genus Austriadraco . [7]

In 1986 fossil jaw fragments containing multicusped teeth were found in Dockum Group rocks in western Texas. One fragment, apparently from a lower jaw, contained two teeth, each with five cusps. Another fragment, from an upper jaw, also contained several multi-cusped teeth. These finds are very similar to Eudimorphodon and may be attributable to this genus, although without better fossil remains it is impossible to be sure. [1]

Many fossils have been found that once were referred to Eudimorphodon, making Eudimorphodon represent one of the most abundant pterosaurs from Italy. [9] Today, these have largely been made separate genera. [10]

Description

Restoration Eudimorphodon NT small.jpg
Restoration

Eudimorphodon was a small pterosaur, being 1 meter (3.3 ft) in length, and weighing no more than 10 kilograms (22 lb). Its fourth finger had a very large size, and attached to the membrane making up the wing. [9]

Eudimorphodon showed a strong differentiation of the teeth, hence its name, which is derived from ancient Greek for "true dimorphic tooth". It also possessed a large number of these teeth, a total of 110 of them densely packed into a jaw only 6 centimeters (2.4 in) long. The front of the jaw was filled with fangs, per side four in the upper jaw, two in the lower jaw, that rather abruptly gave way to a line of smaller multipointed teeth, 25 in the upper jaw, 26 in the lower jaw, most of which had five cusps [3]

The morphology of the teeth are suggestive of a piscivorous diet, which has been confirmed by preserved stomach contents containing the remains of fish of the genus Parapholidophorus . Young Eudimorphodon had slightly differing dentition with fewer teeth and may have had a more insectivorous diet. [3] The top and bottom teeth of Eudimorphodon came into direct contact with each other when the jaws were closed, especially at the back of the jaw. This degree of dental occlusion is the strongest known among pterosaurs. The teeth were multi-cusped, and tooth wear shows that Eudimorphodon was able to crush or chew its food to some degree. Wear along the sides of these teeth suggests that Eudimorphodon also fed on hard-shelled invertebrates. [11] The teeth distinguish Eudimorphodon, because almost all other pterosaurs either had simple teeth, or lacked them altogether. Benson et al. (2012) noticed that the teeth would have been perfect for grabbing and crushing fish. [9]

Phylogeny and classification

Despite its great age, Eudimorphodon has few primitive characteristics [3] making the taxon of little use in attempting to ascertain where pterosaurs fit in the reptile family tree. Basal traits though, are the retention of pterygoid teeth and the flexibility of the tail, which lacks the very long stiffening vertebral extensions other long-tailed pterosaurs possess. The paucity of early pterosaur remains has ensured that their evolutionary origin continues to be a mystery, with different experts suggesting affinities to dinosaurs, archosauriformes, or prolacertiformes.

Within the standard hypothesis that the Dinosauromorpha are the pterosaurs' close relatives within an overarching Ornithodira, Eudimorphodon is also unhelpful in establishing relationships within Pterosauria between early and later forms because then its multicusped teeth should be considered highly derived, compared to the simpler single-cusped teeth of Jurassic pterosaurs, and a strong indicator that Eudimorphodon is not closely related to the ancestor of later pterosaurs. Instead it is believed to be a member of a specialized off branch from the main "line" of pterosaur evolution, the Campylognathoididae. [3] The following phylogenetic analysis follows the topology of Upchurch et al. (2015). [12]

Eopterosauria

In 2020 however, a study upheld by Matthew G. Baron about early pterosaur interrelationships found Eudimorphodon to group with the clade Novialoidea, both within the clade called Lonchognatha. [13]

See also

Related Research Articles

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<i>Preondactylus</i> Genus of preondactylian pterosaur from the Late Triassic

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Anhanguera is a genus of pterodactyloid pterosaur known from the Early Cretaceous Romualdo Formation of Brazil and the Late Cretaceous Kem Kem Group of Morocco. This pterosaur is closely related to Ornithocheirus, but belongs in the family Anhangueridae. The generic name comes from the Tupi words añanga, meaning "spirit protector of the animals" + wera "bygone".

<i>Peteinosaurus</i> Genus of pterosaur from the Late Triassic

Peteinosaurus was a prehistoric genus of pterosaur. It lived in the late Triassic period in the late Norian age, and at a wingspan of around 60 cm (24 in), was one of the smallest and earliest pterosaurs, although other estimates suggest a wingspan of up to 1 m (3.3 ft).

<i>Campylognathoides</i> Genus of campylognathoidid pterosaur from the Early Jurassic

Campylognathoides is an extinct genus of pterosaur discovered in the Württemberg Lias deposits of Germany; this first specimen however, consisted only of wing fragments. Further better preserved specimens were found in the Holzmaden shale; based on these specimens, Felix Plieninger erected a new genus.

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<i>Raeticodactylus</i> Genus of raeticodactylid pterosaur from the Late Triassic

Raeticodactylus is a genus of non-pterodactyloid pterosaur from the late Norian-early Rhaetian-age Upper Triassic lower Kössen Formation of the central Austroalpine of Grisons, Switzerland. It is known from holotype BNM 14524, a single disarticulated partial skeleton including an almost complete skull, found in August 2005. This genus was named and described in 2008 by its discoverer Rico Stecher; the type species is Raeticodactylus filisurensis. The specific name refers to Filisur.

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<i>Carniadactylus</i> Genus of pterosaur from the Late Triassic

Carniadactylus is a genus of pterosaur which existed in Europe during the Late Triassic period. The genus contains a single species, Carniadactylus rosenfeldi.

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<span class="mw-page-title-main">Eopterosauria</span> Clade of basal pterosaurs

Eopterosauria is a proposed clade of basal pterosaurs from the Triassic. The term was first used in Andres et al. (2014) to include Preondactylus, Austriadactylus, Peteinosaurus and Eudimorphodontidae. Inside the group were two other new clades, Preondactylia, which included Preondactylus and Austriadactylus, and Eudimorphodontoidea, to include Eudimorphodontidae and Raeticodactylidae. Eopterosauria was defined as "the least inclusive clade containing Preondactylus buffarinii and Eudimorphodon ranzii". The specimen BSP 1994, previously assigned to Eudimorphodon, was named the separate taxon Austriadraco in 2015, and assigned to the new family Austriadraconidae, but further classification was not described. The following phylogenetic analysis follows the topology of Andres et al. (2014).

<span class="mw-page-title-main">Eudimorphodontidae</span> Family of eopterosaurs from the Late Triassic

Eudimorphodontidae is an extinct family of early pterosaurs from the Late Triassic of Europe. It was named by Peter Wellnhofer in 1978 to include Eudimorphodon ranzii. Some phylogenetic analyses suggested that Eudimorphodontidae is a junior synonym of Campylognathoididae, however more comprehensive analyses found Eudimorphodontidae to be basal to Macronychoptera that includes Campylognathoididae and more derived pterosaurs (Breviquartossa). Wang et al. (2009) found Eudimorphodontidae to include six species, but they didn't defined the clade. Brian Andres define Eudimorphodontidae and found Peteinosaurus to be most closely related to it. Furthermore, he found monophyletic Eudimorphodon clade, and defined two subfamilies within Eudimorphodontidae. The Eudimorphodontinae includes all taxa more closely related to Eudimorphodon ranzii than to Raeticodactylus filisurensis while the Raeticodactylinae includes all taxa more closely related to Raeticodactylus filisurensis than to Eudimorphodon ranzii. More recently, Raeticodactylus and Caviramus were moved into their own family, Raeticodactylidae. The below cladogram follows that analysis.

Arcticodactylus is a genus of basal pterosaur living during the Late Triassic in the area of present-day Greenland. Its only species was previously attributed to Eudimorphodon, and its closest relatives may have been Eudimorphodon or Austriadraco.

Austriadraco is a genus of pterosaur living during the Late Triassic in the area of present Austria. Its only species—Austriadraco dallavecchiai—was previously attributed to Eudimorphodon, and its closest relatives may have been Eudimorphodon or Arcticodactylus.

<i>Bergamodactylus</i> Genus of campylognathoidid pterosaur from the Late Triassic

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<span class="mw-page-title-main">Ornithocheiromorpha</span> Clade of pteranodontoid pterosaurs

Ornithocheiromorpha is a group of pterosaurs within the suborder Pterodactyloidea. Fossil remains of this group date back from the Early to Late Cretaceous periods, around 140 to 92.5 million years ago. Ornithocheiromorphs were discovered worldwide except Antarctica, though most genera were recovered in Europe, Asia and South America. They were the most diverse and successful pterosaurs during the Early Cretaceous, but throughout the Late Cretaceous they were replaced by pteranodontians and azhdarchoids. The Ornithocheiromorpha was defined in 2014 by Andres and colleagues, and they made Ornithocheiromorpha the most inclusive clade containing Ornithocheirus, but not Pteranodon.

<i>Seazzadactylus</i> Genus of austriadraconid pterosaur from the Late Triassic

Seazzadactylus is a basal pterosaur genus that lived during the late Triassic in the area of present-day Italy.

References

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  3. 1 2 3 4 5 Cranfield, I. The Illustrated Directory of Dinosaurs and Other Prehistoric Creatures. London: Salamander Books, Ltd. Pp. 280–281.
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  6. Jenkins, F.A. Jr.; et al. (2001). "A diminutive pterosaur (Pterosauria: Eudimorphodontidae) from the Greenlandic Triassic". Bulletin of the Museum of Comparative Zoology, Harvard University. 155: 487–506.
  7. 1 2 Kellner, Alexander W.A. (2015). "Comments on Triassic pterosaurs with discussion about ontogeny and description of new taxa". Anais da Academia Brasileira de Ciências. 87 (2): 669–689. doi: 10.1590/0001-3765201520150307 . PMID   26131631.
  8. Wellnhofer P., 2003, "A Late Triassic pterosaur from the Northern Calcareous Alps (Tyrol, Austria)". In: Buffetaut E. and Mazin J-M. (Eds), Evolution and Palaeobiology of Pterosaurs, Geological Society of London, Special Publications 217, pp 5–22
  9. 1 2 3 Benson, R.B.J. & Brussatte, S. (2012). Prehistoric Life. London: Dorling Kindersley. pp. 216–217. ISBN   978-0-7566-9910-9.
  10. Vecchia, Dalla; Marco, Fabio (2019). "Seazzadactylus venieri gen. et sp. nov., a new pterosaur (Diapsida: Pterosauria) from the Upper Triassic (Norian) of northeastern Italy". PeerJ. 7: e7363. doi: 10.7717/peerj.7363 . PMC   6661147 . PMID   31380153.
  11. Osi, A. (2010). "Feeding-related characters in basal pterosaurs: implications for jaw mechanism, dental function and diet." Lethaia, doi : 10.1111/j.1502-3931.2010.00230.x
  12. Upchurch, P.; Andres, B.B.; Butler, R.J.; Barrett, P.M. (2015). "An analysis of pterosaurian biogeography: implications for the evolutionary history and fossil record quality of the first flying vertebrates". Historical Biology. 27 (6): 697–717. Bibcode:2015HBio...27..697U. doi:10.1080/08912963.2014.939077. PMC   4536946 . PMID   26339122.
  13. Matthew G. Baron (2020). "Testing pterosaur ingroup relationships through broader sampling of avemetatarsalian taxa and characters and a range of phylogenetic analysis techniques". PeerJ. 8: e9604. doi:10.7717/peerj.9604. PMC 7512134. PMID   33005485.