A four-legged snake from the Early Cretaceous of Gondwana

@article{Martill2015AFS,
  title={A four-legged snake from the Early Cretaceous of Gondwana},
  author={David M. Martill and Helmut Tischlinger and Nicholas R. Longrich},
  journal={Science},
  year={2015},
  volume={349},
  pages={416 - 419}
}
Snakes' four-legged missing link It may surprise you to learn that snakes, like us, are tetrapods derived from an ancient four-legged ancestor. Martill et al. describe a fossil from the Brazilian Cretaceous period that contains a snakelike species that is elongate and serpentine, with both hind- and forelimbs (see the Perspective by Evans). This species appears to have been a burrower and shows clearly the early transitional stages from a lizardlike body plan to the smooth legless snakes we… 
Four legs too many?
  • S. Evans
  • Environmental Science
    Science
  • 2015
TLDR
A remarkable fossil described on page 416 of this issue by Martill et al. (1) combines a snakelike body with fore- and hindlimbs bearing five well-developed digits and brings fresh perspective to the debate on body elongation.
Flap-Footed Lizards (Gekkota: Pygopodidae) Have Forelimbs, Albeit During Embryonic Development
TLDR
Observations on the development of forelimb buds in Delma molleri support gradual limb reduction, as do observations on other limbless lizards, which provide a wealth of opportunities to address modes of limb reduction and loss in squamate reptiles.
The burrowing origin of modern snakes
TLDR
This study provides an extensive comparative data set to test fossoriality quantitatively in stem snakes, and it shows that burrowing was predominant in the lineages leading to modern crown snakes.
Tetrapodophis amplectus is not a snake: re-assessment of the osteology, phylogeny and functional morphology of an Early Cretaceous dolichosaurid lizard
TLDR
It is found that Tetrapodophis shows aquatic adaptations and there is no evidence to support constricting behaviour or macrostomy, and is unambiguously recovered as a dolichosaur.
The Snake Fossil Record from Brazil
TLDR
The Brazilian snake fossil record is crucial for understanding issues about the early evolution of snakes and provides valuable insights into paleobiogeography, paleoenvironmental, and morphological studies.
The ecological origins of snakes as revealed by skull evolution
TLDR
An integrative geometric morphometric approach is used that suggests evolution from terrestrial to fossorial in the most recent common ancestor of extant snakes, and indicates that snakes later evolved novel craniofacial specializations through global acceleration of skull development.
The homologies and evolutionary reduction of the pelvis and hindlimbs in snakes, with the first report of ossified pelvic vestiges in an anomalepidid (Liotyphlops beui)
TLDR
The first example of ossified pelvic vestiges in an anomalepidid snake, Liotyplophs beui, is reported and the evolution, homology and reduction of the pelvic elements and hindlimbs from the oldest known snakes through to living forms are traced.
...
...

References

SHOWING 1-10 OF 50 REFERENCES
A Cretaceous terrestrial snake with robust hindlimbs and a sacrum
TLDR
The new fossil from the Upper Cretaceous period of Patagonia fills an important gap in the evolutionary progression towards limblessness and retains several features associated with a subterranean or surface dwelling life that are also present in primitive extant snake lineages, supporting the hypothesis of a terrestrial rather than marine origin of snakes.
A snake with legs from the marine Cretaceous of the Middle East
TLDR
It is provided compelling evidence that the Cretaceous squamate Pachyrhachis problematicus, previously interpreted as a varanoid lizard, is actually a primitive snake with a well developed pelvis and hindlimbs.
A transitional snake from the Late Cretaceous period of North America
TLDR
Previously undescribed material from this ancient snake is reported, including the maxilla, dentary and additional vertebrae, suggesting that Coniophis is not an anilioid as previously thought and instead represents the most primitive known snake.
The oldest known snakes from the Middle Jurassic-Lower Cretaceous provide insights on snake evolution.
TLDR
Snake fossils that extend the record backwards in time by an additional ~70 million years (Middle Jurassic-Lower Cretaceous) are reported on, suggesting that snakes had undergone habitat differentiation and geographic radiation by the mid-Jurassic.
The Pleistocene serpent Wonambi and the early evolution of snakes
TLDR
None of these three primitive snake lineages shows features associated with burrowing, nor do any of the nearest lizard relatives of snakes (varanoids), which implies that burrowing snakes acquired their fossorial adaptations after the evolution of the snake body form and jaw apparatus in a large aquatic or (surface-active) terrestrial ancestor.
Skull of the large non-macrostomatan snake Yurlunggur from the Australian Oligo-Miocene
TLDR
Two exceptionally preserved skulls from the late Oligocene and early Miocene of northern Australia provide new evidence linking Yurlunggur with Wonambi and other madtsoiids, falsifying predictions of the macrostomatan hypothesis, and supporting the exclusion of Madt soiidae from the clade including all extant snakes.
Anatomy and relationships of Pachyrhachis problematicus, a primitive snake with hindlimbs
TLDR
Pachyrhachis provides additional support for the hypothesis that snakes are most closely related to Cretaceous marine lizards (mosasauroids), and is shown to be the most primitive snake, and the sister–group to all other snakes.
HOW LIZARDS TURN INTO SNAKES: A PHYLOGENETIC ANALYSIS OF BODY‐FORM EVOLUTION IN ANGUID LIZARDS
TLDR
This paper combines a molecular phylogeny for 27 species, morphometric data, and phylogenetic comparative methods to provide the first statistical phylogenetic tests of several long‐standing hypotheses for the evolution of snakelike body form, and finds no support for the hypothesized sequence going from body elongation to limb reduction to digit loss.
A fossil snake with limbs.
TLDR
Phylogenetic analysis of the relationships of the new taxon, as well as reanalysis of Pachyrhachis, shows both to be related to macrostomatans, a group that includes relatively advanced snakes such as pythons, boas, and colubroids to the exclusion of more primitive snake such as blindsnakes and pipesnakes.
THE ANATOMY AND RELATIONSHIPS OF HAASIOPHIS TERRASANCTUS, A FOSSIL SNAKE WITH WELL-DEVELOPED HIND LIMBS FROM THE MID-CRETACEOUS OF THE MIDDLE EAST
TLDR
The species is remarkable in that it shows the skull of a relatively advanced snake, yet preserves well-developed hind limbs, and creates methodological problems for the cladistic analysis of the phylogenetic relationships of these fossil snakes.
...
...