Askeptosauridae is a family of thalattosaurs within the superfamily Askeptosauroidea. Fossils have been found from Italy, Switzerland, and China. Askeptosaurids are distinguished from other thalattosaurs by their long necks and narrow skulls.[1]
| Askeptosauridae | |
|---|---|
| |
| Skeleton of Askeptosaurus italicus | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | †Thalattosauria |
| Superfamily: | †Askeptosauroidea |
| Family: | †Askeptosauridae Kuhn-Schnyder, 1952 |
| Subgroups | |
Classification edit
Askeptosauridae was named in 1952 to include the genus Askeptosaurus.[2] In 2000, the genus Anshunsaurus, which includes two species, was added to the family.[3] In a 2005 phylogenetic analysis, Endennasaurus was included within Askeptosauridae.[4] Later that year a new study placed Endennasaurus outside Askeptosauridae as a basal member of Askeptosauroidea.[1] More recent studies have placed the genus Miodentosaurus from China in the family as well. Below is a cladogram modified from Wu et al. (2009) showing the phylogenetic relationships of askeptosaurids:[5]
| Time Interval | Ma | Country or State | Original ID and collection number | Purpose of Collection |
|---|---|---|---|---|
| Anisian - Ladinian | 247.2 - 237.0 | Switzerland | Askeptosaurus italicus (174993) [4] | Taxonomic Analysis |
| Illyrian - Fassanian | 247.2 - 235.0 | Switzerland | Askeptosaurus italicus (122057) [7] | Taxonomic Analysis |
| Longobardian | 242.0 - 235.0 | China (Yunnan) | Askeptosaurus sp. (196166) [8] | Taxonomic Analysis |
| Longobardian | 242.0 - 235.0 | China (Guizhou) | Anshunsaurus wushaensis, Anshunsaurus huangnihensis (98907) [9] | General Faunal/Floral Analysis |
| Carnian | 237.0 - 228.0 | China (Guizhou) | Anshunsaurus huangguoshuensis, Miodentosaurus brevis (97906) [3] | General Faunal/Floral Analysis |
| Tuvalian | 232.0 - 221.5 | China (Guizhou) | Anshunsaurus huangguoshuensis (85166) [10] | General Faunal/Floral Analysis |
It was assigned to Thalattosauria by Kuhn (1966)[11] and Carroll (1988);[12] and to Askeptosauroidea by Wu et al. (2009).[5]
The Askeptosauridae is known to be from the Alpine Triassic and Southern China. The Endennasaurus is from the Norian age and is a sister taxon of Askeptosaurids. The Askeptoaurus which is the oldest known member of the Askeptosaurids derived from the Northern Tethyan Area.This information proposes that Edennasaurus and future askeptosaurids originated from that Northern Tethyan area.[4]
When the two major thalattosaur assemblages split, the Edennasaurus and Askeptosaurids still kept some similar appendages to each other, such as a relatively well-ossified carpus and tarsus. These bone structures show that these animals still made trips onto the land around them. The development of the elongated neck was for these creatures to better catch their prey. As a longer and more mobile neck gives them more advantage to be able to catch their movable prey.[4]
References edit
- ^ a b Liu, J.; Rieppel, O. (2005). "Restudy of Anshunsaurus huangguoshuensis (Reptilia: Thalattosauria) from the Middle Triassic of Guizhou, China" (PDF). American Museum Novitates (3488): 1–34. doi:10.1206/0003-0082(2005)488[0001:roahrt]2.0.co;2. ISSN 0003-0082. S2CID 55642315.
- ^ Kuhn-Schnyder, E. (1952). "Die Triasfauna der Tessiner Kalkalpen. XVII. Askeptosaurus italicus Nopcsa". Schweizerische Paläontologische Abhandlungen. 69: 1–52.
- ^ a b Rieppel, O.; Liu, J.; Bucher, H. (2000). "The first record of a thalattosaur reptile from the Late Triassic of southern China (Guizhou Province, PR China)". Journal of Vertebrate Paleontology. 20 (3): 507–514. doi:10.1671/0272-4634(2000)020[0507:TFROAT]2.0.CO;2. S2CID 140706921.
- ^ a b c d Müller, J. (2005). "The anatomy of Askeptosaurus italicus from the Middle Triassic of Monte San Giorgio, and the interrelationships of thalattosaurs (Reptilia, Diapsida)". Canadian Journal of Earth Sciences. 42 (7): 1347–1367. Bibcode:2005CaJES..42.1347M. doi:10.1139/e05-030.
- ^ a b Wu, X.-C.; Cheng, Y.-N.; Sato, T.; Shan, H.-Y. (2009). "Miodentosaurus brevis Cheng et al., 2007 (Diapsida: Thalattosauria): its postcranial skeleton and phylogenetic relationships" (PDF). Vertebrata PalAsiatica. 47 (1): 1–20. Archived from the original (PDF) on 2011-11-22. Retrieved 2011-04-23.
- ^ "PBDB". paleobiodb.org. Retrieved 2023-11-07.
- ^ Rieber, H (1970). "Phragmoteuthis ? ticinensis n. sp., ein Coleoidea-Rest aus der Grenzbitumenzone (Mittlere Trias) des Monte San Giorgio (Kt. Tessin, Schweiz)". Paläontologische Zeitschrift. 44 (1–2): 32–40. Bibcode:1970PalZ...44...32R. doi:10.1007/BF02989793. S2CID 129041989.
- ^ Sun, Z; Maisch, M. W.; Hao, W.-C.; Jiang, D (2005). "A Middle Triassic thalattosaur (Reptilia: Diapsida) from Yunnan (China)". Neues Jahrbuch fur Geologie und Palaontologie Monatshefte. 2005 (4): 193–206. doi:10.1127/njgpm/2005/2005/193.
- ^ Rieppel, O; Liu, J; Li, C (2006). "A new species of the thalattosaur genus Anshunsaurus (Reptilia: Thalattosauria) from the Middle Triassic of Guizhou Province, southwestern China". Vertebrata PalAsiatica. 44 (4): 285–296.
- ^ Li, C; Rieppel, O (2002). "A new cyamodontid placodont from Triassic of Guizhou, China". Chinese Science Bulletin. 47 (5): 403–407. Bibcode:2002ChSBu..47..403L. doi:10.1360/02tb9094. S2CID 129796015.
- ^ Kuhn, O. W. M. (1966). Die Reptillien. System und Stammesgeschichte. pp. 1–154.
- ^ R. L. Carroll. 1988. Vertebrate Paleontology and Evolution 1-698 [A. Behrensmeyer/A. Behrensmeyer/M. Uhen]
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