Gwawinapterus

Last updated

Gwawinapterus
Temporal range: Late Cretaceous, 75  Ma
O
S
D
C
P
T
J
K
Pg
N
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Ichthyodectiformes
Family: Saurodontidae
Genus: Gwawinapterus
Arbour & Currie, 2011
Species:
G. beardi
Binomial name
Gwawinapterus beardi
Arbour & Currie, 2011

Gwawinapterus beardi is a species of saurodontid ichthyodectiform fish from the Late Cretaceous period of British Columbia, Canada. While initially described as a very late-surviving member of the pterosaur family Istiodactylidae, further examination has cast doubt on the identification of the specimen as a pterosaur, and research published in 2012 identified the remains as having come from a saurodontid fish.

Contents

Description

Gwawinapterus beardi is known from a single fossil specimen, consisting only of the front half of a skull (upper and lower jaws). The tip of the snout is rounded and deep with a height of about 9.5 centimetres (3.7 in). The tip is about 6.5 centimetres (2.6 in) from the front edge of the largest skull opening, or fenestra. Below this opening the upper jaw is about 21 millimetres (0.83 in) tall. The jaw was originally suggested to be a sutureless fusion of the premaxilla and maxilla of a reptile. Each upper jaw holds at least 26 teeth, eleven or twelve of them below the fenestra; the front of the tooth row has not been preserved and the fossil is broken at its end. The teeth are closely packed. The tooth crowns are small, 4 millimetres (0.16 in) tall and 2.75 millimetres (0.108 in) wide, flattened, and triangular with slightly curved edges. The edges are not serrated, but rounded. The teeth are very straight, showing no curvature to either the back or the middle. The more narrow single tooth roots are relatively long, about 10 to 12 millimetres (0.39 to 0.47 in), for a total tooth length of about 14 millimetres (0.55 in). [1]

The describers have identified two unique derived features (autapomorphies): a number of more than 25 teeth in the upper jaw and a tooth root more than twice as long as the crown. [1]

Discovery and identification

In May 2005, amateur paleontologist Sharon Hubbard found a rock with bones and teeth visible on the surface on a beach near Collishaw Point at Hornby Island, British Columbia, Canada. Accompanying her was Graham Beard, the President of the Vancouver Island Paleontology Museum Society at Qualicum Beach, who added the fossil to its collection. Beard brought the find to the attention of paleontologist Philip J. Currie. He in turn obtained the help of colleague Victoria M. Arbour who identified the specimen as a pterosaur new to science.

In 2011, Arbour and Philip J. Currie described the specimen as the type species of Gwawinapterus beardi. The generic name is derived from Gwa’wina, meaning "raven" in Kwak'wala, the language of the Kwakwaka'wakw, in reference to the similarity of the skull with the stylised raven heads of the hamatsa masks of that tribe, and a Latinised Greek pteron, "wing". The specific name honours Beard. [1]

The rock was sawn in two for better study and its halves, with inventory numbers VIPM 1513a and VIPM 1513b, represent the holotype. It probably originated in marine layers of the Northumberland Formation dating to the late Campanian stage, from about seventy million years ago. [1]

The rock, a calcite nodule, has a length of about 20 centimetres (7.9 in). It holds the snout of the specimen, initially identified as the first pterosaur skull material found in Canada. Some of the surface of the bone is visible; partly it has been preserved as a cross-section or as an imprint. Erupted tooth crowns have disappeared but tooth sockets are still present and due to breakage tooth roots and replacement teeth are visible. [1]

Gwawinapterus was assigned to the Istiodactylidae, using the method of comparative anatomy. By comparison with the skull of the istiodactylid Istiodactylus sinensis , the wingspan of Gwawinapterus has been estimated at three metres. [1] The authors noted that as a pterosaur, it would be the youngest known istiodactylid specimen by forty million years and the only known toothed pterosaur from the Late Cretaceous. This would imply that pterosaur variation had declined less than previously presumed during the Cretaceous period. [1]

However, subsequent research cast doubt on the identification of the specimen as a pterosaur. In a 2012 study of istiodactylid skulls, Mark Witton noted that the Gwawinapterus skull showed a highly unusual pattern of tooth replacement, with new replacement teeth growing directly over older teeth. This aspect of its biology is otherwise unknown in any pterosaur. Witton stated that this "fundamental distinction questions the pterosaurian nature of Gwawinapterus, and may indicate that istiodactylids remain a group exclusively known from the Lower Cretaceous." [2] A more thorough re-examination of the specimen, published in 2012, suggested that the specimen was in fact not a pterosaur but came from a species of saurodontid fish. [3]

See also

Related Research Articles

<i>Irritator</i> Spinosaurid theropod dinosaur genus from the Early Cretaceous Period

Irritator is a genus of spinosaurid dinosaur that lived in what is now Brazil during the Albian stage of the Early Cretaceous Period, about 113 to 110 million years ago. It is known from a nearly complete skull found in the Romualdo Formation of the Araripe Basin. Fossil dealers had acquired this skull and sold it to the State Museum of Natural History Stuttgart. In 1996, the specimen became the holotype of the type species Irritator challengeri. The genus name comes from the word "irritation", reflecting the feelings of paleontologists who found the skull had been heavily damaged and altered by the collectors. The species name is a homage to the fictional character Professor Challenger from Arthur Conan Doyle's novels.

<i>Euoplocephalus</i> Genus of ankylosaurid dinosaur from the Late Cretaceous period

Euoplocephalus is a genus of very large, herbivorous ankylosaurid dinosaurs, living during the Late Cretaceous of Canada. It has only one named species, Euoplocephalus tutus.

<i>Caulkicephalus</i> Genus of anhanguerid pterosaur from the Early Cretaceous

Caulkicephalus is a genus of anhanguerid pterosaur from the Isle of Wight off the coast of England. It lived during the Early Cretaceous period, about 130 million years ago.

<i>Liaoningosaurus</i> Extinct genus of dinosaurs

Liaoningosaurus is an unusual genus of basal ankylosaurid dinosaur from the Liaoning Province, China that lived during the Early Cretaceous in what is now the Yixian and Jiufotang Formation. The type and only species, Liaoningosaurus paradoxus, is known from more than 20 specimens, with some representing juveniles. It was named in 2001 by Xu, Wang and You.

<i>Istiodactylus</i> Genus of istiodactylid pterosaur from the Early Cretaceous

Istiodactylus is a genus of pterosaur that lived during the Early Cretaceous period, about 120 million years ago. The first fossil was discovered on the English Isle of Wight in 1887, and in 1901 became the holotype specimen of a new species, O. latidens, in the genus Ornithodesmus. This species was moved to its own genus, Istiodactylus, in 2001; this name is Greek for "sail finger". More specimens were described in 1913, and Istiodactylus was the only pterosaur known from three-dimensionally preserved fossils for much of the 20th century. In 2006, a species from China, I. sinensis, was assigned to Istiodactylus, but it has also been suggested to belong to a different genus.

<i>Haopterus</i> Genus of pteranodontoid pterosaur from the Early Cretaceous

Haopterus is a genus of pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Yixian Formation of Liaoning, China. Its fossil remains dated back 124.6 million years ago.

Liaoxipterus is a genus of pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The type species is Liaoxipterus brachyognathus. The genus name is derived from the discovery locality Liaoxi and a Latinised Greek pteron, "wing". The specific name is derived from Greek brachys, "short" and gnathos, "jaw".

<i>Nurhachius</i> Genus of istiodactylid pterosaur from the Early Cretaceous

Nurhachius is a genus of istiodactylid pterodactyloid pterosaur from the Barremian to Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. Its fossil remains date back about 120 million years ago.

Longchengpterus, sometimes misspelled as "Lonchengopterus", is a genus of istiodactylid pterodactyloid pterosaur from the Barremian-Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. Its fossil remains dated back about 120 million years ago.

Hongshanopterus is a genus of pterodactyloid pterosaur from the Lower Cretaceous Jiufotang Formation of Liaoning, China.

<span class="mw-page-title-main">Istiodactylidae</span> Family of istiodactyliform pterosaurs

Istiodactylidae is a small family of pterosaurs. This family was named in 2001 after the type genus Istiodactylus was discovered not to be a member of the genus Ornithodesmus.

<i>Ningchengopterus</i> Genus of pterodactyloid pterosaur from the Early Cretaceous

Ningchengopterus is a genus of pterodactyloid pterosaur from the Early Cretaceous period. Its fossil remains were found in the Yixian Formation of what is now China.

Unwindia is a genus of pterodactyloid pterosaur from the Early Cretaceous period of what is now modern-day Brazil.

<i>Guidraco</i> Genus of anhanguerid pterosaur from the Early Cretaceous period

Guidraco is an extinct genus of toothed pterodactyloid pterosaur known from the Early Cretaceous of Liaoning Province, northeast China. According to many recent studies, Guidraco is a member of the group Anhanguerinae, a subfamily belonging to the larger group Anhangueridae.

<i>Cimoliopterus</i> Genus of pterosaur from the Cretaceous period

Cimoliopterus is a genus of pterosaur that lived during the Late Cretaceous in what is now England and the United States. The first known specimen, consisting of the front part of a snout including part of a crest, was discovered in the Grey Chalk Subgroup of Kent, England, and described as the new species Pterodactylus cuvieri in 1851. The specific name cuvieri honours the palaeontologist George Cuvier, whereas the genus Pterodactylus was then used for many pterosaur species that are not thought to be closely related today. It was among the first pterosaurs to be depicted as sculptures, in Crystal Palace Park in the 1850s. The species was subsequently assigned to various other genera, including Ornithocheirus and Anhanguera. In 2013, the species was moved to a new genus, as Cimoliopterus cuvieri; the generic name Cimoliopterus is derived from the Greek words for "chalk" and "wing". Other specimens and species have also been assigned to or synonymised with the species with various levels of certainty. In 2015, a snout discovered in the Britton Formation of Texas, US, was named as a new species in the genus, C. dunni; the specific name honours its collector, Brent Dunn.

The Northumberland Formation is a Late Cretaceous (?Campanian-?Maastrichtian)-aged geologic formation in Canada. It belongs to the larger Nanaimo Group. Indeterminate bird and pterosaur fossils have been recovered from the formation, as well as a potential gladius of Eromangateuthis. An extensive diversity of shark teeth is known from the formation; many appear to be closely allied with modern deep-water shark taxa, suggesting a deep-water environment for the formation. The most well-known exposures of the formation are on Hornby Island.

<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.

Pangupterus is a genus of pterodactyloid pterosaur from the Early Cretaceous Jiufotang Formation of China. It was first described and named by Lü Junchang et al.

<i>Forfexopterus</i> Genus of ctenochasmatid pterosaur from the Early Cretaceous

Forfexopterus is a genus of ctenochasmatid pterosaur from the Early Cretaceous Jiufotang Formation in China. It contains a single species, F. jeholensis, named from a mostly complete skeleton by Shunxing Jiang and colleagues in 2016. A second specimen, consisting of a wing, was described in 2020. While the first specimen is larger, it shows signs of being less mature than the second specimen, indicating that the developmental trajectories of Forfexopterus were variable. Like other ctenochasmatids, Forfexopterus had a long, low skull filled with many slender teeth; unlike other members of the group, however, it did not have a spatula-shaped snout tip or crests, and its teeth were more curved. A single characteristic distinguishes Forfexopterus from all other members of the wider group Archaeopterodactyloidea: of the four phalanx bones in its wing finger, the first was shorter than the second but longer than the third.

<i>Mimodactylus</i> Genus of Late Cretaceous pterosaur

Mimodactylus is a genus of istiodactyliform pterosaur that lived in what is now Lebanon during the Late Cretaceous, 95 million years ago. The only known specimen was discovered in a limestone quarry near the town of Hjoula, belonging to the Sannine Formation. The owner of the quarry allowed the specimen to be prepared and scientifically described by an international team of researchers, and when it was eventually sold, the buyer donated it to the MIM Museum in Beirut. In 2019, the researchers named the new genus and species Mimodactylus libanensis; the generic name refers to the MIM Museum, combined with the Greek word daktylos for "digit", and the specific name refers to Lebanon. The well-preserved holotype specimen is the first complete pterosaur from the Afro-Arabian continent, and the third pterosaur fossil known from Lebanon.

References

  1. 1 2 3 4 5 6 7 Arbour, Victoria M. & Philip J. Currie (2011). "An istiodactylid pterosaur from the Upper Cretaceous Nanaimo Group, Hornby Island, British Columbia, Canada". Canadian Journal of Earth Sciences. 48 (1): 63–69. Bibcode:2011CaJES..48...63S. doi:10.1139/E10-083.
  2. Witton, Mark P. (2012). "New insights into the skull of Istiodactylus latidens (Ornithocheiroidea, Pterodactyloidea)". PLoS ONE. 7 (3): e33170. doi: 10.1371/journal.pone.0033170 .
  3. Vullo, Romain; Buffetaut, Eric & Everhart, Michael J. (2012). "Reappraisal of Gwawinapterus beardi from the Late Cretaceous of Canada: a saurodontid fish, not a pterosaur". Journal of Vertebrate Paleontology. 32 (5): 1198–1201. doi:10.1080/02724634.2012.681078.