Recumbirostra

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title: "Recumbirostra" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["microsauria", "pennsylvanian-first-appearances", "cisuralian-extinctions"] description: "Extinct clade of tetrapods" topic_path: "general/microsauria" source: "https://en.wikipedia.org/wiki/Recumbirostra" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct clade of tetrapods ::

| fossil_range = Late Carboniferous - Early Permian, | 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. 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.

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. 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. 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, or the result of incorrect character encoding. 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. Furthermore, the taxa that are often considered to be recumbirostrans have been found among amphibians (and not as a distinct clade) in some analyses.

Classification

Taxonomy

• Altenglanerpeton
• Sparodus
• Steenerpeton?
• Trihecaton?
• Hapsidopareiidae
• Microbrachidae?
• Pantylidae
• Odonterpetidae
  • Odonterpeton
  • Joermungandr
• Chthonosauria
  • Brachystelechidae
  • Lysorophia?
• Nastrondormes
  • Gymnarthridae
  • Rhynchonkidae / Goniorhynchidae
    • Aletrimyti
    • Dvellecanus
    • Rhynchonkos
  • Ostodolepidae

Phylogeny

Below is a cladogram showing the phylogenetic relationships of recumbirostrans from Glienke (2012):

|label1=Recumbirostra |1={{clade |label1=Microbrachidae |1={{clade |1=Microbrachis}} |2={{clade |1={{clade |label1=Pantylidae |1={{clade |1=Pantylus}} |2={{clade |1=Stegotretus |2=Sparodus}} }} |2={{clade |1={{clade |label1=Gymnarthridae |1={{clade |1={{clade |1=Cardiocephalus sternbergi |2=Cardiocephalus peabodyi}} |2={{clade |1=Euryodus primus |2=Euryodus dalyae}} }} |label2=Ostodolepidae |2={{clade |1=Pelodosotis |2=Micraroter}} }} |2={{clade |1={{clade |label1=Goniorhynchidae |1={{clade |1=Rhynchonkos}} |2=Eocaecilia}} |2={{clade |1={{clade |1=Tambaroter |2=Altenglanerpeton}} |label2=Brachystelechidae |2={{clade |1=Batropetes |2=Carrolla |3=Quasicaecilia

Gallery

References

References

1. (2021). "Joermungandr bolti, an exceptionally preserved 'microsaur' from the Mazon Creek Lagerstätte reveals patterns of integumentary evolution in Recumbirostra". Royal Society Open Science.
2. (2019-09-30). "Diabloroter bolti, a short-bodied recumbirostran 'microsaur' from the Francis Creek Shale, Mazon Creek, Illinois". Zoological Journal of the Linnean Society.
3. (2022-03-28). "Snake-like limb loss in a Carboniferous amniote". Nature Ecology & Evolution.
4. (2012). "A new "microsaur" (Amphibia; Lepospondyli) from the Rotliegend of the Saar–Palatinate region (Carboniferous/Permian transition; West Germany)". Paläontologische Zeitschrift.
5. (2019). "''Infernovenator steenae'', a new serpentine recumbirostran from the 'Mazon Creek' Lagerstätte further clarifies lysorophian origins". Zoological Journal of the Linnean Society.
6. [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]
7. (2017). "Hidden morphological diversity among early tetrapods". Nature.
8. Anderson, J.S.. (2007). "Major Transitions in Vertebrate Evolution". Indiana University Press.
9. 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.
10. Jason D. Pardo, Matt Szostakiwskyj and Jason S. Anderson. (2015). "Phylogenetic relationships of recumbirostran 'lepospondyls' inferred from neurocranial morphology". Society of Vertebrate Paleontology 75th Annual Meeting Program & Abstracts.
11. (2022). "Osteology and phylogenetic position of the diminutive 'microsaur' ''Odonterpeton triangulare'' from the Pennsylvanian of Linton, Ohio, and major features of recumbirostran phylogeny". Zoological Journal of the Linnean Society.
12. (2024-12-31). "Recumbirostran 'microsaurs' are not amniotes". Journal of Systematic Palaeontology.
13. Modesto, Sean P.. (2024-04-02). "Problems of the interrelationships of crown and stem amniotes". Frontiers in Earth Science.
14. Henrici, A.C.. (2011). "An ostodolepid 'microsaur' (Lepospondyli) from the Lower Permian Tambach Formation of central Germany". Journal of Vertebrate Paleontology.
15. (4 January 2019). "Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix". PeerJ.
16. (2025-01-07). "The recumbirostran ''Hapsidopareion lepton'' from the early Permian (Cisuralian: Artinskian) of Oklahoma reassessed using HRμCT, and the placement of Recumbirostra on the amniote stem". [[Papers in Palaeontology]].

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