Ericiolacerta
Ericiolacerta | |
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Ericiolacerta parva | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Synapsida |
Clade: | Therapsida
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Clade: | †Therocephalia |
Family: | †Ericiolacertidae |
Genus: | †Ericiolacerta Watson, 1931 |
Species: | †E. parva
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Binomial name | |
†Ericiolacerta parva Watson, 1931
|
Ericiolacerta is an extinct genus of small
Discovery
The Ericiolacerta holotype specimen Ericiolacerta parva was discovered in 1931 in the Katberg Formation of the Beaufort Group near Harrismith, Free State in South Africa and described by Professor David Meredith Seares Watson in an article for the Zoological Society of London.[1][3] It was discovered by A. W. Putterill within a cornerstone block of limestone from the shales of the Lystrosaurus Assemblage Zone, placing it between ~251-249 Ma during the early Triassic.[1] The specimen consisted of a nearly complete skeleton with a slightly crushed skull. Watson described it as being closely related to the Therocephalian Scaloposaurus based on their skull morphology but as a new member of the family Scaloposauridae founded by Broom in 1914 based on differences in its dentition and jaw structure.[1] This classification was later changed as this family was invalidated and many of its members were moved into the superfamily Baurioidea.[4]
Another specimen was discovered in 1971 in the Lower Triassic Fremouw Formation of the
Description
Ericiolacerta parva was described as a small, fossilized reptile preserved extremely well, despite the skull being partially crushed before it was buried, resulting in distortion of the occipital, otic, and mandibular bones, as well as the loss of part of the premaxillae and zygoma. The specimen is also missing twelve vertebrae from its midsection, but besides these the skeleton is completely preserved.[1] The curled position of the skeleton is similar to that assumed by many small mammals when they die, and the displacement of the bones was determined to be as a result of the movement and rotting of still-attached skin. The cause of the fractured skull was attributed to a larger animal likely stepping on the body.[1] The specimen's total length from snout to the hind end of the pelvis was measured to be 17 centimetres (6.7 in).[1] It was notable for the small size and irregularity of its teeth, the reduction/lack of canine teeth, the large size of its head and pectoral girdle compared to its relatively small pelvic girdle, and its long, slender limbs.[1] By comparison, the Antarctic mandible from 1981 was described as being from a larger Ericiolacerta parva specimen, but maintained the small tooth size, irregularity, and reduced canines seen in the dentition of the African specimen.[2] Both specimens demonstrate a slender dentary with a smooth, rounded ventral margin, which was determined by Huttenlocker & Sidor (2012) to be a compelling apomorphy in diagnosing the species.[2][5] The presence of a tuber calcis on the posterior side of the calcaneum in the specimen was revised as a poor character in assigning Ericiolacerta parva and was used to reevaluate the hindlimbs of the Antarctic specimen as belonging to an indeterminate Eutherocephalian.[5]
Paleobiology
As a member of the
Paleoenvironment
Ericiolacerta parva appears in the Lystrosaurus Biozone in South Africa, as well as the lower Fremouw in Antarctica during the Triassic.[7] The Antarctic environment during the Triassic in the Fremouw Formation has been reconstructed containing dense forested areas located along riverbanks and floodplains. These forests contained a dense layer of Dicroidium leaflitter and existed as far south as ~70-75°.[13] Analysis of fossilized trees and plant matter by Cúneo et al. (2003) determined that Antarctica experienced very favorable seasons of plant growth and described evidence of a cooling climate during the Late Triassic which the Antarctic ecosystem would be the first to respond to due to its high latitude. These conditions created an environment that was ripe for speciation, resulting in an explosion of diversity in the region.[13] Studies of species such as Ericiolacerta which have been found in both the Karoo Basin of South Africa and the Fremouw Formation in Antarctica have determined that several species first appeared in Antarctica before later appearing in South Africa, providing evidence towards Antarctica being a hotspot for speciation.[8][7] In the early Triassic, African flora was rich. The vegetation was used as shelter and food for numerous insects Ericiolacerta fed on.[14]
Classification
Ericiolacerta belongs to the order Therocephalia within the clade Eutherocephalia, and placed in the superfamily Baurioidea in the Ericiolacertidae family.[15][4] It was initially classified within the now-obsolete group Scaloposauria which is now considered to likely represent juvenile forms of various therocephalians, at which point Ericiolacerta was reclassified within Baurioidea.[4] Below is a cladogram of Baurioidea adapted from Huttenlocker (2009) and Huttenlocker & Sidor (2012).[16][5]
See also
References
- ^ .
- ^ a b c d e f g Colbert, Edwin H.; Kitching, James W. (1981). "Scaloposaurian reptiles from the Triassic of Antarctica". American Museum Novitates (2709): 1–22.
- ^ a b c "Ericiolacerta". Paleofile. Retrieved 5 April 2022.
- ^ ISSN 0272-4634.
- ^ S2CID 55745212.
- S2CID 10995542.
- ^ S2CID 131582010.
- ^ ISSN 0031-0239.
- ^ a b c Watson, D.M.S.; Romer, A.S. (1956). "A classification of therapsid reptiles". Bulletin of the Museum of Comparative Zoology. 114 (2): 37–89.
- PMID 12965004.
- S2CID 29300018.
- ^ PMID 35931742.
- ^ ISSN 0031-0182.
- ^ The Complete Guide to Dinosaurs and Prehistoric Reptiles, Chris McNab and prof. Michael Benton, Marshall Editions, London 2006.
- ISSN 0370-2774.
- ISSN 0024-4082.