Pleurodira

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Pleurodira
Temporal range: Late Jurassic to present 163–present  Ma
Eastern long neck tortoise - chelodina longicollis03.jpg
Eastern long-necked turtle
Chelodina longicollis
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Clade: Pan-Pleurodira
Suborder: Pleurodira
Cope, 1865 [1]
Synonyms [2]
  • Pleuroderes - Duméril and Bibron 1834:354 [3]
  • Pleurodera - Lichtenstein 1856:2 [4]
  • Pleurodera- Cope 1864:181 [5]
  • Pleurodira - Cope 1865:186 [1]

The Pleurodira are one of the two living suborders of turtles, the other being the Cryptodira. The division between these two suborders represents a very deep evolutionary divide between two very different types of turtles. The physical differences between them, although anatomical and largely internal, are nonetheless significant, and the zoogeographic implications of them are substantial. The Pleurodira are known more commonly as the side-necked turtles and the name Pleurodira quite literally translates to side neck, whereas the Cryptodira are known as hidden-necked turtles. [6] The Pleurodira turtles are currently restricted to freshwater habitats in the Southern Hemisphere, largely to Australia, South America, and Africa. Within the Pleurodira, three living families are represented: Chelidae, also known as the Austro-South American side-necked turtles, the Pelomedusidae, also known as the African mud terrapins, and the Podocnemididae, also known as the American side-neck river turtles. [6] [7] However, they were cosmopolitan clade during the Cretaceous and most of the Cenozoic, and even occurred in marine environments around the world. [8] [9]

Contents

Definition and description

Pelomedusa subrufa showing typical pleurodiran neck retraction, under the shell and towards the side. Pelomedusa subrufa (cropped).JPG
Pelomedusa subrufa showing typical pleurodiran neck retraction, under the shell and towards the side.

The Pleurodira are identified by the method with which they withdraw their heads into their shells. In these turtles, the neck is bent in the horizontal plane, drawing the head into a space in front of one of the front legs. A larger overhang of the carapace helps to protect the neck, which remains partially exposed after retraction. This differs from the method employed by a cryptodiran, which tucks its head and neck between its forelegs, within the shell.

Differences in neck retraction between cryptodirans and pleurodirans. Turtle neck retraction.svg
Differences in neck retraction between cryptodirans and pleurodirans.

The different methods of bending the neck require completely different anatomies of the cervical vertebrae. All extant turtles studied so far have eight vertebrae in the neck. [10] In the Pleurodira, these vertebrae are narrow in cross-section and spool-shaped with biconvex centra on one or more of the cervicals. [10] These centra act as a double joint, allowing a large degree of sideways movement and providing a means of folding the neck onto itself in the lateral plane. Conversely, in the Cryptodira, the neck bones are wide and flat. The biconvex centra in some of the cryptodiran cervicals allow the neck to fold onto itself in the vertical plane. [10]

Pleurodirans also differ from cryptodirans in the emarginations of their skulls. Skull emargination provides room and anchorage for the jaw muscles. The connection points and the position of the emarginations relate to different bones of the skull.

Another difference is in the arrangement of the bones of the shell and the scutes overlaying them. Pleurodiran turtles have 13 scutes on the plastron of the shell, whereas cryptodiran turtles have only 12. The extra scute is called the intergular and is at the front of the plastron between the gular scutes. Pelomedusid turtles also possess mesoplastra, further differentiating this group.

The jaw closure mechanism has articulation on trochlear surfaces of the pterygoid.

Suction feeding

One of the three extant families in this suborder is the family Chelidae, which have a specially adapted strategy for catching prey. While the majority of the family Chelidae are omnivores, 17 species are carnivorous: [7] Chelus fimbriatus and species of the Chelodina genus. [7] This special strategy is referred to as a gape-suck mechanism. [7] [11] The turtle first opens its mouth little by little. Then, when the turtle is within striking range of the prey, it will open its mouth completely, sucking in water at such a rate that the current into its mouth is too strong for prey to escape and it engulfs the prey within 0.004 seconds. [11] This strategy also circumvents issues to quick capture of underwater prey, such as resistance to rapid movement in water, pressure waves due to a rapid strike, and rapid water intake when feeding. [11]

Taxonomy

[12] [13] [14]

After Ferreria, et al. 2018. [15]

Related Research Articles

<span class="mw-page-title-main">Turtle</span> Order of reptiles characterized by a shell

Turtles are reptiles of the order Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira and Cryptodira, which differ in the way the head retracts. There are 360 living and recently extinct species of turtles, including land-dwelling tortoises and freshwater terrapins. They are found on most continents, some islands and, in the case of sea turtles, much of the ocean. Like other amniotes they breathe air and do not lay eggs underwater, although many species live in or around water.

<span class="mw-page-title-main">Chelidae</span> Family of turtles

Chelidae is one of three living families of the turtle suborder Pleurodira, and are commonly called Austro-South American side-neck turtles. The family is distributed in Australia, New Guinea, parts of Indonesia, and throughout most of South America. It is a large family of turtles with a significant fossil history dating back to the Cretaceous. The family is entirely Gondwanan in origin, with no members found outside Gondwana, either in the present day or as a fossil.

<span class="mw-page-title-main">Pelomedusidae</span> Family of turtles

Pelomedusidae is a family of freshwater turtles endemic to sub-Saharan Africa, including Madagascar, São Tomé, and the Seychelles. They range in size from 12 to 45 cm in carapace length, and are generally roundish in shape. They are unable to fully withdraw their heads into their shells, instead drawing them to the side and folding them beneath the upper edge of their shells, hence are called African side-necked turtles.

<span class="mw-page-title-main">Podocnemididae</span> Family of turtles

Podocnemididae is a family of pleurodire (side-necked) turtles, once widely distributed. Most of its 41 genera and 57 species are now extinct. Seven of its eight surviving species are native to South America: the genus Peltocephalus, with two species, only one of which is extant ; and the genus Podocnemis, with six living species of South American side-necked river turtles and four extinct. There is also one genus native to Madagascar: Erymnochelys, the Madagascan big-headed turtle, whose single species E. madagascariensis.

<span class="mw-page-title-main">Cryptodira</span> Suborder of reptiles

The Cryptodira are a suborder of Testudines that includes most living tortoises and turtles. Cryptodira is commonly called the "Hidden-Neck Turtles" or the "Inside-Neck Turtles". Cryptodira differ from Pleurodira in that they lower their necks and pull the heads straight back into the shells, instead of folding their necks sideways along the body under the shells' marginals. They include among their species freshwater turtles, snapping turtles, tortoises, softshell turtles, and sea turtles.

<span class="mw-page-title-main">Protostegidae</span> Extinct family of turtles

Protostegidae is a family of extinct marine turtles that lived during the Cretaceous period. The family includes some of the largest sea turtles that ever existed. The largest, Archelon, had a head one metre (39 in) long. Like most sea turtles, they had flattened bodies and flippers for front appendages; protostegids had minimal shells like leatherback turtles of modern times.

<span class="mw-page-title-main">Bothremydidae</span> Extinct family of turtles

Bothremydidae is an extinct family of side-necked turtles (Pleurodira) known from the Cretaceous and Cenozoic. They are closely related to Podocnemididae, and are amongst the most widely distributed pleurodire groups, with their fossils having been found in Africa, India, the Middle East, Europe, North America and South America. Bothremydids were aquatic turtles with a high morphological diversity, indicative of generalist, molluscivorous, piscivorous and possibly herbivorous grazing diets, with some probably capable of suction feeding. Unlike modern pleurodires, which are exclusively freshwater, bothremydids inhabited freshwater, marine and coastal environments. Their marine habits allowed bothremydids to disperse across oceanic barriers into Europe and North America during the early Late Cretaceous (Cenomanian). The youngest records of the group are indeterminate remains from Saudi Arabia and Oman, dating to the Miocene.

<i>Cearachelys</i> Extinct genus of turtles

Cearachelys is an extinct genus of pleurodiran turtle which existed some 110 million years ago. The genus is monotypic, with only type species Cearachelys placidoi known.

<span class="mw-page-title-main">Elrhaz Formation</span>

The Elrhaz Formation is a geological formation in Niger, West Africa.

<i>Chelodina canni</i> Species of turtle

Chelodina canni, also known commonly as Cann's snake-necked turtle, is a species of turtle in the family Chelidae. The species is endemic to Australia, where it is found in the northern and northeastern parts of the continent. It has a narrow zone of hybridization with its related species the eastern snake-necked turtle, C. longicollis. For many years C. canni was assumed to be the same species as C. novaeguineae from New Guinea. However, in 2002 it was shown that these two species differ both morphologically and genetically, and therefore C. canni was separated and described as a unique species.

Prochelidella is an extinct genus of Early to Late Cretaceous chelid turtles from the Bajo Barreal, Candeleros, Cerro Barcino and Portezuelo Formations of the Cañadón Asfalto, Golfo San Jorge and Neuquén Basins in Patagonia, Argentina. It includes the following species:

<span class="mw-page-title-main">West African mud turtle</span> Species of turtle

The West African mud turtle, also known as the West African side-necked turtle or swamp terrapin, is a species of turtle in the family Pelomedusidae. Pelusios castaneus is a freshwater species and is endemic to West and Central Africa.

<span class="mw-page-title-main">Araripemydidae</span> Extinct family of turtles

Araripemydidae is a family of freshwater aquatic turtles belonging to the order Pleurodira, known from the Early Cretaceous of South America and Africa. The family contains two recognised monotypic genera, Araripemys and Taquetochelys, from the Santana Group of Brazil and the Elrhaz Formation of Niger, respectively, which date to the Aptian-Albian stages of the Early Cretaceous. They are consider to be the most basal lineage within the Pelomedusoides. They are thought to have been specialised suction feeders. Laganemys was named in 2013 but was later determined to be synonymous with Taquetochelys.

<i>Galianemys</i> Extinct genus of turtle

Galianemys is an extinct genus of turtle in the family Bothremydidae, discovered in the Kem Kem Beds.

Araiochelys is an extinct genus of bothremydid pleurodiran turtle that was discovered in the Ouled Abdoun Basin, Morocco. The genus consists solely of type species A. hirayamai.

Eotaphrosphys is an extinct genus of bothremydid pleurodiran turtle that was discovered in the Mont Aime Formation, France. Originally assigned to the genus "Tretosternum", it consists exclusively of type species E. ambiguum.

Carteremys is an extinct genus of pelomedusid pleurodiran turtle from the Maastrichtian -Eocene, of India based on the type species C. leithi, which was named in 1953 by E. Williams and was originally placed in the genera Hydraspis by H. J. Carter in 1852 and Testudo, also by H. J. Carter, in 1871. A second species, C. pisdurensis, was named in 1977 by Sohan Lal Jain, but it was transferred to the separate genus Jainemys in 2020 by Joyce and Bandyopadhyay.

<i>Amabilis uchoensis</i> Extinct species of turtles

Amabilis uchoensis is a species of prehistoric pleurodiran turtle from the Late Cretaceous of South America. It is the only species in the genus Amabilis.

References

  1. 1 2 Cope, E. D. (1865). "Third Contribution to the Herpetology of Tropical America". Proceedings of the Academy of Natural Sciences of Philadelphia. 17 (4): 185–198. JSTOR   4624040.
  2. ↑ Van Dijk, Peter Paul; Iverson, John; Shaffer, H. Bradley; Bour, Roger; Rhodin, Anders (2012). "Turtles of the World, 2012 Update: Annotated Checklist of Taxonomy, Synonymy, Distribution, and Conservation Status". Conservation Biology of Freshwater Turtles and Tortoises. doi:10.3854/crm.5.000.checklist.v5.2012. ISBN   978-0965354097.
  3. ↑ Duméril, C.; Baird, Spencer Fullerton; Bibron, Gabriel; Duméril, Auguste Henri André (1834). "Erpétologie générale, ou, Histoire naturelle complète des reptiles / Par A.M.C. Duméril et par G. Bibron". doi: 10.5962/bhl.title.45973 .{{cite journal}}: Cite journal requires |journal= (help)
  4. ↑ Lichtenstein, Heinrich. (1856). "Nomenclator reptilium et amphibiorum musei zoologici Berolinensis : Namenverzeichnis der in der zoologischen Sammlung der Koeniglichen Universität zu Berlin aufgestellten Arten von Reptilien und Amphibien nach ihren Ordnungen, Familien und Gattungen / (Mit Vorrede von H. Lichtenstein)". doi: 10.5962/bhl.title.45245 .{{cite journal}}: Cite journal requires |journal= (help)
  5. ↑ Cope, E. D. (1864). "On the Limits and Relations of the Raniformes". Proceedings of the Academy of Natural Sciences of Philadelphia. 16 (4): 181–183. JSTOR   4623931.
  6. 1 2 Pritchard, Peter Charles Howard; Trebbau, Pedro (1984). The Turtles of Venezuela. Society for the Study of Amphibians and Reptiles. p. 403. ISBN   9780916984113.
  7. 1 2 3 4 Vitt, L. and Caldwell, J. (2014). Herpetology: An Introductory Biology of Amphibians and Reptiles. Academic Press. pp. 523–543.{{cite book}}: CS1 maint: multiple names: authors list (link)
  8. ↑ Gaffney, Eugene S.; Tong, Haiyan; Meylan, Peter A. (2006). "Evolution of the Side-Necked Turtles: The Families Bothremydidae, Euraxemydidae, and Araripemydidae" (PDF). Bulletin of the American Museum of Natural History. 300: 1–698. doi:10.1206/0003-0090(2006)300[1:EOTSTT]2.0.CO;2. ISSN   0003-0090. S2CID   85790134.
  9. ↑ Pérez-García, Adán (2016). "A new turtle confirms the presence of Bothremydidae (Pleurodira) in the Cenozoic of Europe and expands the biostratigraphic range of Foxemydina". The Science of Nature. 103 (7–8): 50. Bibcode:2016SciNa.103...50P. doi:10.1007/s00114-016-1375-y. PMID   27262289. S2CID   15652309.
  10. 1 2 3 Romer, Alfred (1956). Osteology of the Reptiles. Chicago: University of Chicago Press. p. 772.
  11. 1 2 3 Lemell, P., Lemell, C., Snelderwaard, P., Gumpenberger, M., Wocheslander, R., and Weisgram, J. (2002). "Feeding patterns of Chelus fimbriatus (Pleurodira: Childae)". The Journal of Experimental Biology. 205 (Pt 10): 1495–1506. doi:10.1242/jeb.205.10.1495. PMID   11976360.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. ↑ "The Paleobiology Database". Paleodb.org. Retrieved 2012-09-24.
  13. ↑ Joyce, Walter G.; Anquetin, Jérémy; Cadena, Edwin-Alberto; Claude, Julien; Danilov, Igor G.; Evers, Serjoscha W.; Ferreira, Gabriel S.; Gentry, Andrew D.; Georgalis, Georgios L.; Lyson, Tyler R.; Pérez-García, Adán (2021-02-09). "A nomenclature for fossil and living turtles using phylogenetically defined clade names". Swiss Journal of Palaeontology . 140 (1): 5. Bibcode:2021SwJP..140....5J. doi: 10.1186/s13358-020-00211-x . hdl: 11336/155192 . ISSN   1664-2384.
  14. ↑ Joyce, Walter G.; Rollot, Yann; Evers, Serjoscha W.; Lyson, Tyler R.; Rahantarisoa, Lydia J.; Krause, David W. (2021). "A new pelomedusoid turtle, Sahonachelys mailakavava, from the Late Cretaceous of Madagascar provides evidence for convergent evolution of specialized suction feeding among pleurodires". Royal Society Open Science. 8 (5): 210098. Bibcode:2021RSOS....810098J. doi: 10.1098/rsos.210098 . PMC   8097199 . PMID   34035950.
  15. ↑ Ferreira, Gabriel S.; Bronzati, Mario; Langer, Max C.; Sterli, Juliana (2018). "Phylogeny, biogeography and diversification patterns of side-necked turtles (Testudines: Pleurodira)". Royal Society Open Science. 5 (3): 171773. Bibcode:2018RSOS....571773F. doi:10.1098/rsos.171773. PMC   5882704 . PMID   29657780.
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