A Cretaceous terrestrial snake with robust hindlimbs and a sacrum

@article{Apestegua2006ACT,
  title={A Cretaceous terrestrial snake with robust hindlimbs and a sacrum},
  author={Sebasti{\'a}n Apestegu{\'i}a and Hussam Zaher},
  journal={Nature},
  year={2006},
  volume={440},
  pages={1037-1040}
}
It has commonly been thought that snakes underwent progressive loss of their limbs by gradual diminution of their use. However, recent developmental and palaeontological discoveries suggest a more complex scenario of limb reduction, still poorly documented in the fossil record. Here we report a fossil snake with a sacrum supporting a pelvic girdle and robust, functional legs outside the ribcage. The new fossil, from the Upper Cretaceous period of Patagonia, fills an important gap in the… 
View on Nature
ncbi.nlm.nih.gov
152 Citations
Highly Influential Citations
16
Background Citations
61
Methods Citations
7
Results Citations
7

152 Citations

A four-legged snake from the Early Cretaceous of Gondwana
TLDR
A fossil from the Brazilian Cretaceous period that contains a snakelike species that is elongate and serpentine, with both hind- and forelimbs, suggests that crown Serpentes originated in Gondwana.
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.
A mid-Cretaceous embryonic-to-neonate snake in amber from Myanmar
TLDR
The first known fossil baby snake (Late Cretaceous amber, Myanmar) shows that some ancient snakes lived in marginal marine forests, and the new species is the first Mesozoic snake to be found in a forested environment, indicating greater ecological diversity among early snakes than previously thought.
New skulls and skeletons of the Cretaceous legged snake Najash, and the evolution of the modern snake body plan
TLDR
Light is shed on the acquisition of the snake body plan using micro–computed tomography scans of the first three-dimensionally preserved skulls of the legged snake Najash and a new phylogenetic hypothesis to elucidate the initial sequence of bone loss that gave origin to the modern snake skull.
Reevaluation of the Anatomy of the Cenomanian (Upper Cretaceous) Hind-Limbed Marine Fossil Snakes Pachyrhachis, Haasiophis, and Eupodophis
ABSTRACT New anatomical observations and reinterpretations of previously identified structures have resulted in new taxonomic diagnoses for the fossil hind-limbed marine snakes Pachyrhachis…
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 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.
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 evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash
TLDR
The anatomy of these fossil taxa unambiguously shows that free cervical and caudal intercentra attached to distinct downgrowths of the centra, are present in basal fossil snakes, and agrees with the proposed loss of post atlas-axisintercentra in later evolving snakes.
...
...

References

SHOWING 1-10 OF 22 REFERENCES
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 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 phylogenetic relationships of Pachyrhachis problematicus, and the evolution of limblessness in snakes (Lepidosauria, Squamata)
EXCEPTIONALLY PRESERVED SKELETONS OF THE CRETACEOUS SNAKE DINILYSIA PATAGONICA WOODWARD, 1901
For over one hundred years the Upper Cretaceous snake Dinilysia patagonica has been known from only the holotype skull and associated vertebrae (Smith-Woodward, 1901; Estes et al., 1970; Frazetta,…
The origin of snake feeding
TLDR
Evidence is presented that mosasaurs — large, extinct marine lizards related to snakes — represent a crucial intermediate stage in snake skull evolution, and intermediate morphologies inSnake skull evolution should perhaps be sought not in small burrowing lizards, as commonly assumed, but in large marine forms.
Snake phylogeny based on osteology, soft anatomy and ecology
Relationships between the major lineages of snakes are assessed based on a phylogenetic analysis of the most extensive phenotypic data set to date (212 osteological, 48 soft anatomical, and three…
Cranial morphology of the Plio-Pleistocene giant madtsoiid snake Wonambi naracoortensis
TLDR
New material and additional morphological details of a rare and phylogenetically significant large fossil snake, Wonambi naracoortensis Smith, 1976, are described from Pleistocene and Pliocene cave deposits in southern South Australia and show that differences between snakes and other squamates have sometimes been overstated.
A MORPHOLOGICAL MODEL AND CT ASSESSMENT OF THE SKULL OF PACHYRHACHIS PROBLEMATICUS (SQUAMATA, SERPENTES), A 98 MILLION YEAR OLD SNAKE WITH LEGS FROM THE MIDDLE EAST
Pachyrhachis problematicus is a snake with well-developed hind limbs known from two specimens from the Cenomanian of the Middle East. One specimen has a complete and articulated, albeit crushed…
ON THE PHYLOGENETIC RELATIONSHIPS OF THE CRETACEOUS SNAKES WITH LEGS, WITH SPECIAL REFERENCE TO PACHYRHACHIS PROBLEMATICUS (SQUAMATA, SERPENTES)
TLDR
Several aspects of character delimitations as proposed by Caldwell are reviewed, and corroborate the macrostomatan affinities of Pachyrhachis.
The earliest dromaeosaurid theropod from South America
TLDR
A near-complete, small dromaeosaurid is described that is both the most complete and the earliest member of the Maniraptora from South America and which provides new evidence for a unique Gondwanan lineage of DromaeOSauridae with an origin predating the separation between northern and southern landmasses.
...
...