Carrolla Temporal range: | |
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Recontruction of the head. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | † Microsauria |
Family: | † Brachystelechidae |
Genus: | † Carrolla Langston & Olson, 1986 |
Species: | †C. craddocki |
Binomial name | |
†Carrolla craddocki Langston & Olson, 1986 | |
Carrolla is an extinct genus of brachystelechid 'microsaur' that lived in the Lower Permian in North America. It was named in 1986 by American paleontologists Wann Langston and Everett Olson. The type species, Carrolla craddocki, is the only known species.
Carrolla was named for the type species by Langston & Olson (1986) for a single, complete skull collected from the early Permian of Archer County, Texas; the specimen is reposited at the Texas Memorial Museum in Austin. [1] They immediately recognized the similarity to 'Brachystelechus,' the eponymous genus from Europe; this genus was subsequently synonymized with Batropetes, traditionally considered a reptile but which had taxonomic precedent. [2] Numerous features were cited as evidence for an ability to burrow, which was considered rare among 'microsaurs' at the time, and several shared features with modern amphibians were noted, although some of these have been subsequently disproven. Maddin et al. (2011) provided a detailed re-description of the holotype based on CT data; this study was one of the first to explore 'microsaur' anatomy using tomographic methods. [3] These authors provided substantial new information on the internal anatomy, particularly the braincase, and recovered support for close affinities of brachystelechids and caecilians in the longstanding debate over the origin of modern amphibians. Mann et al. (2019) reported the first postcrania of the taxon based on a small block that was catalogued with the holotype skull but never described; the authors indicate that correspondence with K.W. Craddock, who found the holotype, corroborates that the postcrania block was recovered in association with the skull. [4] The authors also validated Glienke's (2015) [5] previous cursory interpretation of at least some of the teeth as tricuspid, a feature found in some other brachystelechids.
The most recent diagnosis was provided by Maddin et al. (2011) [3] and includes features such as a short, wide skull with a well-ossified anterior braincase. Some of the diagnostic features have been shown to be shared with other taxa following similar CT analyses of additional 'microsaurs'; more recent work on other brachystelechids including Glienke (2015) [5] and Pardo et al. (2015) [6] have provided additional features that separate those taxa from Carrolla. For example, both Quasicaecilia and Carrolla share extensively ossified posterior braincases and anterior braincases, but the morphology of some features, such as the element termed the 'presphenoid' by Pardo et al. differs between them. The presence of bicuspid teeth was reported by Langston & Olson, a feature of great interest because it has traditionally been considered to be a feature linking them to modern amphibians, the only living tetrapods with bicuspid teeth, but subsequent workers identified tricuspidity in the holotype. [4]
Below is the strict consensus tree from Mann & Maddin (2019): [7]
Microsauria is an extinct, possibly polyphyletic order of tetrapods from the late Carboniferous and early Permian periods. It is the most diverse and species-rich group of lepospondyls. Recently, Microsauria has been considered paraphyletic, as several other non-microsaur lepospondyl groups such as Lysorophia seem to be nested in it. Microsauria is now commonly used as a collective term for the grade of lepospondyls that were originally classified as members of Microsauria.
Eocaecilia is an extinct genus of gymnophionan amphibian from the early Jurassic Kayenta Formation of Arizona, United States. One species is described, Eocaecilia micropodia.
Wann Langston Jr. was an American paleontologist and professor at the University of Texas at Austin.
Acroplous is an extinct genus of dvinosaurian Temnospondyli within the family Eobrachyopidae.
Batropetes is an extinct genus of brachystelechid recumbirostran "microsaur". Batropetes lived during the Sakmarian stage[a] of the Early Permian. Fossils attributable to the type species B. fritschi have been collected from the town of Freital in Saxony, Germany, near the city of Dresden. Additional material has been found from the Saar-Nahe Basin in southwestern Germany and has been assigned to three additional species: B. niederkirchensis, B. palatinus, and B. appelensis.
Euryodus is an extinct genus of microsaur within the family Gymnarthridae. Euryodus is a Lepospondyl from the clade Microsauria that lived during the Lower Permian. The name comes from Greek, meaning ‘broad-tooth’. It has been found in the southern half of North America, from its original discovery in Texas up to Utah.
Leiocephalikon is an extinct genus of microsaur in the family Gymnarthridae. The type species is Amblyodon problematicum named by John William Dawson in 1882. Its fossil was found in the Joggins Formation which hailed from Carboniferous period. Although sometimes regarded as primitive gymnarthrids, Leiocephalikon classification is still debated as its fossil is scarce.
Odonterpeton is an extinct genus of "microsaur" from the Late Carboniferous of Ohio, containing the lone species Odonterpeton triangulare. It is known from a single partial skeleton preserving the skull, forelimbs, and the front part of the torso. The specimen was found in the abandoned Diamond Coal Mine of Linton, Ohio, a fossiliferous coal deposit dated to the late Moscovian stage, about 310 million years ago.
Pariotichus is an extinct genus of gymnarthrid microsaurs from the early Permian of Texas.
Tersomius is an extinct genus of dissorophoid temnospondyl within the family Micropholidae. It is known from the early Permian of North America.
Stegotretus is an extinct genus of microsaur referred to the Pantylidae. It is known from the Carboniferous–Permian boundary Cutler Formation exposures of New Mexico.
Brachystelechidae is an extinct family of Early Permian microsaurs. The family was first named by Robert L. Carroll and Pamela Gaskill in 1978, with the only member being Brachystelechus fritschi. Brachystelechus fritschi has since been reassigned to the genus Batropetes. Genera assigned to the family include: Batropetes, from Germany; Carrolla, from Texas; Quasicaecilia, also from Texas; Diabloroter, from the Mazon Creek lagerstätte of Illinois; and Bromerpeton from the Tambach Formation of Germany.
Tuditanomorpha is a suborder of microsaur tetrapods. Tuditanomorphs lived from the Late Carboniferous to the Early Permian and are known from North America and Europe. Tuditanomorphs have a similar pattern of bones in the skull roof. Tuditanomorphs display considerable variability, especially in body size, proportions, dentition, and presacral vertebral count. Currently there are four families of tuditanomorphs, with two being monotypic. Tuditanids first appear in the Lower Pennsylvanian. Goniorhynchidae, Hapsidopareiidae, and Trihecatontidae appear in the Late Pennsylvanian and Early Permian.
Ostodolepidae, also spelled Ostodolepididae, is an extinct family of Early Permian tetrapods. Initially they were considered microsaurs, but later were assigned to the group Recumbirostra. Ostodolepids were relatively large, reaching lengths of up to 2 feet (61 cm), terrestrial, and presumably fossorial. Ostodolepid remains have been found from Early Permian beds in Texas, Oklahoma, and Germany.
Nannaroter is an extinct genus of Recumbirostran tetrapod within the family Ostodolepidae.
Recumbirostra is a clade of tetrapods which lived during the Carboniferous and Permian periods. They are thought to have had a fossorial (burrowing) lifestyle and the group includes both short-bodied and long-bodied snake-like forms. At least one species, the long-bodied molgophid Nagini mazonense, lost its forelimbs entirely. Recumbirostra includes the families Pantylidae, Gymnarthridae, Ostodolepidae, Rhynchonkidae and Brachystelechidae, with additional families such as Microbrachidae and Molgophidae being included by some authors. Brachystelechidae and Molgophidae have also been grouped together in the suggested clade Chthonosauria.
Huskerpeton is an extinct genus of recumbirostran from the Early Permian period. They belong to the order Microsauria, which was established in 1863 by Dawson, and was quickly expanded to include many different small taxa. They lived in what is now Nebraska and Kansas. The holotype of Huskerpeton was uncovered at the Eskridge formation in Nebraska, which is part of how it got its name.
Proxilodon is an extinct genus of recumbirostran microsaur from the Early Permian Speiser Formation of Kansas, United States. It contains a single species, Proxilodon bonneri,.
The Vale Formation is a geological formation in north-central Texas, a component of the Texas red beds preserving sediments and fossils from the Early Permian Leonardian series. It occupies the middle part of the Clear Fork Group, above the Arroyo Formation and below the Choza Formation. Some sources consider the Vale Formation to be merely an informal subunit of the Clear Fork Formation, thus renaming it to the Middle Clear Fork Formation.
Hillary Catherine Maddin is a Canadian paleontologist and developmental biologist known for her work on development in extinct and extant amphibians. She is currently an associate professor in the Department of Earth Sciences at Carleton University.