Casineria is an extinct genus of tetrapod which lived about 340-334 million years ago in the Mississippian epoch of the Carboniferous period. Its generic name, Casineria, is a latinization of Cheese Bay, the site near Edinburgh, Scotland where the holotype fossil was found.[1] When originally described in 1999, it was identified as a transitional fossil noted for its mix of basal (amphibian-like) and advanced (reptile-like) characteristics, putting it at or very near the origin of the amniotes, the group containing all mammals, birds, modern reptiles, and other descendants of their reptile-like common ancestor. However, the sole known fossil is lacking key elements such as a skull, making exact analysis difficult.[2] As a result, the classification of Casineria has been more controversial in analyses conducted since 1999. Other proposed affinities include a placement among the lepospondyls,[3]seymouriamorphs,[4] "gephyrostegids",[5] or as a synonym of Caerorhachis, another controversial tetrapod which may have been an early temnospondyl.[6]
Casineria was a small animal with a postcrania length estimated to have been 15 centimeters. Its small size would have made it ideal for hunting the invertebrates of the Carboniferous.[1]
Casineria had five fingers, with the bones at the finger tip being tapering and curved. This spurred the initial describers to argue that it was the oldest known animal with claws on each hand, and marks the earliest clawed foot.[1] Claws are extremely rare among amphibians, but ubiquitous among amniotes, so their supposed presence in Casineria has been considered to be evidence towards its amniote identity. Claws are also a feature intimately bound to the formation of keratinous scales in reptiles, so in life, Casineria would have borne scaly, reptilian-type skin, and would have resembled a small lizard (despite being only distantly related to true lizards).[7]
Under the hypothesis that it was among the first amniotes in the biological sense, it would have laid an amniotic egg not dependent on being laid in water to survive, possibly hiding them in damp vegetation or hollowed out tree stumps. This has been inferred from the fact that Casineria was found in rocks showing a rather dry environment.[1] In the early Carboniferous period before the appearance of Casineria, vertebrates were primarily aquatic, only spending part of their time on land. Casineria was believed to be among the first vertebrates to live and reproduce on land.
However, later studies have not consistently placed Casineria as an early amniote.[3][4][6] Even the presence of claws has been considered doubtful, as Marjanovic & Laurin (2019) noted that the finger tips were squared-off, rather than pointed.[5]
Discovery
Location of Cheese Bay in Great Britain
In 1992, an amateur fossil collector spotted the remnants of this four-legged creature on the shore of Cheese Bay, Scotland.[8] For the next five years, the fossil languished at the National Museum of Scotland in Edinburgh while researchers focused on other projects. Consisting of a slab and counterslab (compression fossil) of a single partial skeleton, the fossil was cataloged with the specimen designation NMS G.1993.54.1. Around 1997, work began to expose the remainder of the fossil from the surrounding matrix. The work revealed that the animal probably lived in an environment much drier than previously understood. The findings were first reported in the April 8, 1999 edition of Nature.[1]
Classification
While retaining a general build like those found in the amphibian reptiliomorph groups like Seymouriamorpha and Diadectomorpha, Casineria also shows features that tie it in with early reptiles, notably a generally gracile build with light leg bones, unfused ankles and toes terminating in claws. This would enable the animal to use their feet actively in traction, rather than as holdfasts, an indication of a primarily terrestrial lifestyle.[1] These traits have been argued to show that it was more closely related to amniotes than to other known reptiliomorph amphibians.
With its advanced features, Casineria may have been one of the first true amniotes, and thus the first reptile under traditional classification. In phylogenetic parlance it would have been a stem amniote, close to, but outside the crown group Amniota (the group consisting of the last common ancestor of synapsids and sauropsids and all its descendants). Casineria pushes back the origin of amniote lineages much earlier than was previously assumed.[1] However, like with much of the basal tetrapod stock, the phylogenetic position is uncertain, and it has also been suggested Casineria is a lepospondyl,[3]seymouriamorph,[4] synonymous with Caerorhachis (which is possibly a basal temnospondyl amphibian),[6] or part of a grade of small tetrapods traditionally considered the family Gephyrostegidae.[5]
^ abcdefgPaton, R. L.; Smithson, T. R.; Clack, J. A. (8 April 1999). "An amniote-like skeleton from the Early Carboniferous of Scotland". Nature. 398 (6727): 508–513. Bibcode:1999Natur.398..508P. doi:10.1038/19071. ISSN 0028-0836. S2CID 204992355.
^Monastersky, R. (1999): Out of the Swamps, How early vertebrates established a foothold—with all 10 toes—on land, Science News vol. 155, No. 21, p. 328
^ abcClack, Jennifer A.; Witzmann, Florian; Müller, Johannes; Snyder, Daniel (2012-10-18). "A Colosteid-Like Early Tetrapod from the St. Louis Limestone (Early Carboniferous, Meramecian), St. Louis, Missouri, USA". Fieldiana Life and Earth Sciences. 5: 17–39. doi:10.3158/2158-5520-5.1.17. ISSN 2158-5520. S2CID 129964161.
^ abcClack, Jennifer A.; Bennett, Carys E.; Carpenter, David K.; Davies, Sarah J.; Fraser, Nicholas C.; Kearsey, Timothy I.; Marshall, John E. A.; Millward, David; Otoo, Benjamin K. A. (2016-12-05). "Phylogenetic and environmental context of a Tournaisian tetrapod fauna". Nature Ecology & Evolution. 1 (1): 0002. doi:10.1038/s41559-016-0002. ISSN 2397-334X. PMID 28812555. S2CID 22421017.
^ abcMarjanović, David; Laurin, Michel (2019-01-04). "Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix". PeerJ. 6: e5565. doi:10.7717/peerj.5565. ISSN 2167-8359. PMC6322490. PMID 30631641.
^ abcChapter 6: "Walking with early tetrapods: evolution of the postcranial skeleton and the phylogenetic affinities of the Temnospondyli (Vertebrata: Tetrapoda)." In: Kat Pawley (2006). "The postcranial skeleton of temnospondyls (Tetrapoda: temnospondyli)." PhD Thesis. La Trobe University, Melbourne.
^Alibardi, L. (2008): Microscopic analysis of lizard claw morphogenesis and hypothesis on its evolution. Acta Zoologica: Morphology and Evolution, vol 89 (2): pp 169–178. abstract
^(PDF). Archived from the original (PDF) on 2008-07-28. Retrieved 2008-03-22.{{cite web}}: CS1 maint: archived copy as title (link)
Further reading
Richard Monastersky, "Out of the Swamps: How early vertebrates established a foothold—with all 10 toes—on land", The Weekly Newsmagazine of Science, Volume 155, Number 21 (May 22, 1999)
The Encyclopedia of Dinosaurs & Prehistoric Creatures/Dougal Dixon
August 04, 2023
casineria, extinct, genus, tetrapod, which, lived, about, million, years, mississippian, epoch, carboniferous, period, generic, name, latinization, cheese, site, near, edinburgh, scotland, where, holotype, fossil, found, when, originally, described, 1999, iden. Casineria is an extinct genus of tetrapod which lived about 340 334 million years ago in the Mississippian epoch of the Carboniferous period Its generic name Casineria is a latinization of Cheese Bay the site near Edinburgh Scotland where the holotype fossil was found 1 When originally described in 1999 it was identified as a transitional fossil noted for its mix of basal amphibian like and advanced reptile like characteristics putting it at or very near the origin of the amniotes the group containing all mammals birds modern reptiles and other descendants of their reptile like common ancestor However the sole known fossil is lacking key elements such as a skull making exact analysis difficult 2 As a result the classification of Casineria has been more controversial in analyses conducted since 1999 Other proposed affinities include a placement among the lepospondyls 3 seymouriamorphs 4 gephyrostegids 5 or as a synonym of Caerorhachis another controversial tetrapod which may have been an early temnospondyl 6 CasineriaTemporal range Early Carboniferous 340 334 Ma PreꞒ Ꞓ O S D C P T J K Pg NThe counterslab of the holotype fossilScientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataSuperclass TetrapodaClade ReptiliomorphaClade Amniota Genus CasineriaPaton Smithson amp Clack 1999Type species Casineria kiddiPaton Smithson amp Clack 1999 Contents 1 Description 2 Discovery 3 Classification 4 See also 5 References 6 Further readingDescription Edit RestorationCasineria was a small animal with a postcrania length estimated to have been 15 centimeters Its small size would have made it ideal for hunting the invertebrates of the Carboniferous 1 Casineria had five fingers with the bones at the finger tip being tapering and curved This spurred the initial describers to argue that it was the oldest known animal with claws on each hand and marks the earliest clawed foot 1 Claws are extremely rare among amphibians but ubiquitous among amniotes so their supposed presence in Casineria has been considered to be evidence towards its amniote identity Claws are also a feature intimately bound to the formation of keratinous scales in reptiles so in life Casineria would have borne scaly reptilian type skin and would have resembled a small lizard despite being only distantly related to true lizards 7 Under the hypothesis that it was among the first amniotes in the biological sense it would have laid an amniotic egg not dependent on being laid in water to survive possibly hiding them in damp vegetation or hollowed out tree stumps This has been inferred from the fact that Casineria was found in rocks showing a rather dry environment 1 In the early Carboniferous period before the appearance of Casineria vertebrates were primarily aquatic only spending part of their time on land Casineria was believed to be among the first vertebrates to live and reproduce on land However later studies have not consistently placed Casineria as an early amniote 3 4 6 Even the presence of claws has been considered doubtful as Marjanovic amp Laurin 2019 noted that the finger tips were squared off rather than pointed 5 Discovery Edit Location of Cheese Bay in Great BritainIn 1992 an amateur fossil collector spotted the remnants of this four legged creature on the shore of Cheese Bay Scotland 8 For the next five years the fossil languished at the National Museum of Scotland in Edinburgh while researchers focused on other projects Consisting of a slab and counterslab compression fossil of a single partial skeleton the fossil was cataloged with the specimen designation NMS G 1993 54 1 Around 1997 work began to expose the remainder of the fossil from the surrounding matrix The work revealed that the animal probably lived in an environment much drier than previously understood The findings were first reported in the April 8 1999 edition of Nature 1 Classification EditWhile retaining a general build like those found in the amphibian reptiliomorph groups like Seymouriamorpha and Diadectomorpha Casineria also shows features that tie it in with early reptiles notably a generally gracile build with light leg bones unfused ankles and toes terminating in claws This would enable the animal to use their feet actively in traction rather than as holdfasts an indication of a primarily terrestrial lifestyle 1 These traits have been argued to show that it was more closely related to amniotes than to other known reptiliomorph amphibians With its advanced features Casineria may have been one of the first true amniotes and thus the first reptile under traditional classification In phylogenetic parlance it would have been a stem amniote close to but outside the crown group Amniota the group consisting of the last common ancestor of synapsids and sauropsids and all its descendants Casineria pushes back the origin of amniote lineages much earlier than was previously assumed 1 However like with much of the basal tetrapod stock the phylogenetic position is uncertain and it has also been suggested Casineria is a lepospondyl 3 seymouriamorph 4 synonymous with Caerorhachis which is possibly a basal temnospondyl amphibian 6 or part of a grade of small tetrapods traditionally considered the family Gephyrostegidae 5 See also Edit Paleontology portalSolenodonsaurus WestlothianaReferences Edit a b c d e f g Paton R L Smithson T R Clack J A 8 April 1999 An amniote like skeleton from the Early Carboniferous of Scotland Nature 398 6727 508 513 Bibcode 1999Natur 398 508P doi 10 1038 19071 ISSN 0028 0836 S2CID 204992355 Monastersky R 1999 Out of the Swamps How early vertebrates established a foothold with all 10 toes on land Science News vol 155 No 21 p 328 a b c Clack Jennifer A Witzmann Florian Muller Johannes Snyder Daniel 2012 10 18 A Colosteid Like Early Tetrapod from the St Louis Limestone Early Carboniferous Meramecian St Louis Missouri USA Fieldiana Life and Earth Sciences 5 17 39 doi 10 3158 2158 5520 5 1 17 ISSN 2158 5520 S2CID 129964161 a b c Clack Jennifer A Bennett Carys E Carpenter David K Davies Sarah J Fraser Nicholas C Kearsey Timothy I Marshall John E A Millward David Otoo Benjamin K A 2016 12 05 Phylogenetic and environmental context of a Tournaisian tetrapod fauna Nature Ecology amp Evolution 1 1 0002 doi 10 1038 s41559 016 0002 ISSN 2397 334X PMID 28812555 S2CID 22421017 a b c Marjanovic David Laurin Michel 2019 01 04 Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix PeerJ 6 e5565 doi 10 7717 peerj 5565 ISSN 2167 8359 PMC 6322490 PMID 30631641 a b c Chapter 6 Walking with early tetrapods evolution of the postcranial skeleton and the phylogenetic affinities of the Temnospondyli Vertebrata Tetrapoda In Kat Pawley 2006 The postcranial skeleton of temnospondyls Tetrapoda temnospondyli PhD Thesis La Trobe University Melbourne Alibardi L 2008 Microscopic analysis of lizard claw morphogenesis and hypothesis on its evolution Acta Zoologica Morphology and Evolution vol 89 2 pp 169 178 abstract Archived copy PDF Archived from the original PDF on 2008 07 28 Retrieved 2008 03 22 a href Template Cite web html title Template Cite web cite web a CS1 maint archived copy as title link Further reading EditRichard Monastersky Out of the Swamps How early vertebrates established a foothold with all 10 toes on land The Weekly Newsmagazine of Science Volume 155 Number 21 May 22 1999 The Encyclopedia of Dinosaurs amp Prehistoric Creatures Dougal Dixon Retrieved from https en wikipedia org w index php title Casineria amp oldid 1161502236, wikipedia, wiki, book, books, library,
