Recumbirostra

{{Short description|Extinct clade of tetrapods}}

{{Automatic taxobox

| fossil_range = Late Carboniferous - Early Permian, {{fossilrange|323.2|293.52}}

| image = Rhynchonkos.jpg

| image_caption = Life restoration of the rhynchonkid Rhynchonkos

| image2 = Batropetes.jpg

| image2_caption = Life restoration of Batropetes, a brachystelechid

| taxon = Recumbirostra

| authority = Anderson, 2007

| subdivision_ranks = Subgroups

| subdivision = see text

}}

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.{{Cite journal |last1=Mann |first1=Arjan |last2=Calthorpe |first2=Ami S. |last3=Maddin |first3=Hillary C. |title=Joermungandr bolti, an exceptionally preserved 'microsaur' from the Mazon Creek Lagerstätte reveals patterns of integumentary evolution in Recumbirostra |journal=Royal Society Open Science |year=2021 |volume=8 |issue=7 |pages=210319 |doi=10.1098/rsos.210319 |pmc=8292758 |pmid=34295525|bibcode=2021RSOS....810319M }}{{Cite journal |last1=Mann |first1=Arjan |last2=Maddin |first2=Hillary C |date=2019-09-30 |title=Diabloroter bolti, a short-bodied recumbirostran 'microsaur' from the Francis Creek Shale, Mazon Creek, Illinois |url=https://academic.oup.com/zoolinnean/article/187/2/494/5497448 |journal=Zoological Journal of the Linnean Society |language=en |volume=187 |issue=2 |pages=494–505 |doi=10.1093/zoolinnean/zlz025 |issn=0024-4082|url-access=subscription }} At least one species, the long-bodied molgophid Nagini mazonense, lost its forelimbs entirely.{{Cite journal |last1=Mann |first1=Arjan |last2=Pardo |first2=Jason D. |last3=Maddin |first3=Hillary C. |date=2022-03-28 |title=Snake-like limb loss in a Carboniferous amniote |url=http://dx.doi.org/10.1038/s41559-022-01698-y |journal=Nature Ecology & Evolution |volume=6 |issue=5 |pages=614–621 |doi=10.1038/s41559-022-01698-y |pmid=35347258 |bibcode=2022NatEE...6..614M |s2cid=247778148 |issn=2397-334X|url-access=subscription }} Recumbirostra includes the families Pantylidae, Gymnarthridae, Ostodolepidae, Rhynchonkidae and Brachystelechidae, with additional families such as Microbrachidae and Molgophidae being included by some authors.{{Cite journal | last1 = Glienke | first1 = S. | doi = 10.1007/s12542-012-0130-8 | title = A new "microsaur" (Amphibia; Lepospondyli) from the Rotliegend of the Saar–Palatinate region (Carboniferous/Permian transition; West Germany) | journal = Paläontologische Zeitschrift | volume = 86 | issue = 3 | pages = 297–311 | year = 2012 | bibcode = 2012PalZ...86..297G | s2cid = 140699792 }}{{cite journal |last1=Mann |first1=A. |last2=Pardo |first2=J. D. |last3=Maddin |first3=H. C. |title=Infernovenator steenae, a new serpentine recumbirostran from the 'Mazon Creek' Lagerstätte further clarifies lysorophian origins |journal=Zoological Journal of the Linnean Society |date=2019 |volume=187 |issue=2 |pages=506–517 |doi=10.1093/zoolinnean/zlz026}} Brachystelechidae and Molgophidae have also been grouped together in the suggested clade Chthonosauria.[https://academic.oup.com/zoolinnean/advance-article/doi/10.1093/zoolinnean/zlac043/6646571?login=false Osteology and phylogenetic position of the diminutive 'microsaur' Odonterpeton triangulare from the Pennsylvanian of Linton, Ohio, and major features of recumbirostran phylogeny]

Recumbirostra was erected as a clade in 2007 to include many of the taxa traditionally grouped in "Microsauria", which has since been shown to be a paraphyletic or polyphyletic grouping.{{Cite journal|author1=Jason D. Pardo |author2=Matt Szostakiwskyj |author3=Per E. Ahlberg |author4=Jason S. Anderson |year=2017 |title=Hidden morphological diversity among early tetrapods |journal=Nature |volume=546 |issue=7660 |pages=642–645 |doi=10.1038/nature22966 |pmid=28636600 |bibcode=2017Natur.546..642P |hdl=1880/113382 |s2cid=2478132 |hdl-access=free }}{{cite book |last=Anderson |first=J.S. |year=2007 |chapter=Incorporating ontogeny into the matrix: A phylogenetic evaluation of developmental evidence for the origin of modern Amphibians |title=Major Transitions in Vertebrate Evolution |editor1=Anderson, J.S. |editor2=Sues, H.-D. |publisher=Indiana University Press |location=Bloomington and Indianapolis |pages=182–227}}Huttenlocker, A. K.; Pardo, J. D.; Small, B. J.; Anderson, J. S. (2013). "Cranial morphology of recumbirostrans (Lepospondyli) from the Permian of Kansas and Nebraska, and early morphological evolution inferred by micro-computed tomography". Journal of Vertebrate Paleontology 33 (3): 540. Like other "microsaurs", the recumbirostrans have traditionally been considered to be members of the subclass Lepospondyli; however, many phylogenetic analyses conducted since the 2010s have recovered recumbirostrans as basal sauropsid (reptilian) amniotes instead.{{cite journal |author=Jason D. Pardo, Matt Szostakiwskyj and Jason S. Anderson |year=2015 |title=Phylogenetic relationships of recumbirostran 'lepospondyls' inferred from neurocranial morphology |journal=Society of Vertebrate Paleontology 75th Annual Meeting Program & Abstracts |pages=191 }}{{Cite journal|last1=Mann |first1=A. |last2=Pardo |first2=J. D. |last3=Sues |first3=H.-D. |year=2022 |title=Osteology and phylogenetic position of the diminutive 'microsaur' Odonterpeton triangulare from the Pennsylvanian of Linton, Ohio, and major features of recumbirostran phylogeny |journal=Zoological Journal of the Linnean Society |volume=197 |issue=3 |pages=641–655 |doi=10.1093/zoolinnean/zlac043 |doi-access=free }} However, the placement of recumbirostrans as reptiles has been challenged by other authors, who have recovered them as stem-amniotes instead, and contended that the shared characters between recumbirostrans and reptiles are convergent,{{Cite journal |last1=Reisz |first1=Robert R. |last2=Maho |first2=Tea |last3=Modesto |first3=Sean P. |date=2024-12-31 |title=Recumbirostran 'microsaurs' are not amniotes |url=https://www.tandfonline.com/doi/full/10.1080/14772019.2023.2296078 |journal=Journal of Systematic Palaeontology |language=en |volume=22 |issue=1 |doi=10.1080/14772019.2023.2296078 |bibcode=2024JSPal..2296078R |issn=1477-2019|url-access=subscription }} or the result of incorrect character encoding.{{Cite journal |last=Modesto |first=Sean P. |date=2024-04-02 |title=Problems of the interrelationships of crown and stem amniotes |journal=Frontiers in Earth Science |volume=12 |doi=10.3389/feart.2024.1155806 |doi-access=free |bibcode=2024FrEaS..1255806M |issn=2296-6463}} Not all phylogenetic analyses recognize Recumbirostra as a valid grouping. An alternative clade called Tuditanomorpha is occasionally supported and includes many of the same taxa.{{cite journal |last=Henrici |first=A.C. |author2=Martens, T. |author3=Berman, D.S. |author4= Sumida, S.S. |year=2011 |title=An ostodolepid 'microsaur' (Lepospondyli) from the Lower Permian Tambach Formation of central Germany |journal=Journal of Vertebrate Paleontology |volume=31 |issue=5 |pages=997–1004 |doi=10.1080/02724634.2011.596601 |bibcode=2011JVPal..31..997H |s2cid=129710688 |url=http://www.bioone.org/doi/10.1080/02724634.2011.596601 |url-access=subscription }} Furthermore, the taxa that are often considered to be recumbirostrans have been found among amphibians (and not as a distinct clade) in some analyses.{{cite journal |last1=Marjanović |first1=David |last2=Laurin |first2=Michel |title=Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix |journal=PeerJ |date=4 January 2019 |volume=6 |pages=e5565 |doi=10.7717/peerj.5565 |doi-access=free |pmid=30631641 |pmc=6322490 |language=en |issn=2167-8359}}