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Skeleton of Joermungandr bolti, showing preserved remains of scales -
Skeleton of the brachystelechid Batropetes -
Skull of the molgophid Brachydectes -
Skull of the ostodolepid Nannaroter
| Recumbirostra Temporal range: Late Carboniferous - Early Permian,
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| Life restoration of the rhynchonkid Rhynchonkos | |
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| Life restoration of Batropetes, a brachystelechid | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | †Microsauria |
| Clade: | †Recumbirostra Anderson, 2007 |
| Subgroups | |
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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.[1][2] At least one species, the long-bodied molgophid Nagini mazonense, lost its forelimbs entirely.[3] Recumbirostra includes the families Pantylidae, Gymnarthridae, Ostodolepidae, Rhynchonkidae and Brachystelechidae, with additional families such as Microbrachidae and Molgophidae being included by some authors.[4][5] Brachystelechidae and Molgophidae have also been grouped together in the suggested clade Chthonosauria.[6]
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.[7][8][9] 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.[10][7][5][3][11] 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,[12] or the result of incorrect character encoding.[13] 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.[14]
