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, | |
|---|---|
 | |
| Life restoration of the rhynchonkid Rhynchonkos | |
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| Life restoration of Batropetes , a brachystelechid | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Reptiliomorpha |
| Clade: | † Recumbirostra Anderson, 2007 |
| Subgroups | |
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]
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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] Furthermore, the taxa that are often considered to be recumbirostrans have been found among amphibians (and not as a distinct clade) in some analyses. [15]
