Repeated evolution of limblessness and digging heads in worm lizards revealed by DNA from old bones

Kearney, Maureen; Stuart, Bryan L.

doi:10.1098/rspb.2004.2771

Cited by 125 publications

(138 citation statements)

References 29 publications

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“…Analysis of morphological data using molecular constraints recovers the Rhineuridae as the oldest split within Amphisbaenia, as found previously [7,10,12,13,30]. Within Rhineuridae, the Palaeocene Archaerhineura and Plesiorhineura lie at the base of a Palaeogene radiation, which ultimately dwindles to the single extant species, Rhineura floridana.…”

Section: Resultsmentioning

confidence: 79%

“…The remaining families, Cadeidae, Trogonophidae and Amphisbaenidae, form a clade, with trogonophids and amphisbaenids forming a clade originating in Africa, Afrobaenia, as in previous molecular [12,13,30] and morphological [7] analyses; Todrasaurus gheerbrandti, from the Palaeocene of Africa, may represent a stem member of this lineage. Listromycter leakyi and Lophocranion rusingensis, from the African Miocene [31] are found to represent crown members of the Amphisbaenidae.…”

Section: Resultsmentioning

confidence: 92%

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Biogeography of worm lizards (Amphisbaenia) driven by end-Cretaceous mass extinction

et al. 2015

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Worm lizards (Amphisbaenia) are burrowing squamates that live as subterranean predators. Their underground existence should limit dispersal, yet they are widespread throughout the Americas, Europe and Africa. This pattern was traditionally explained by continental drift, but molecular clocks suggest a Cenozoic diversification, long after the break-up of Pangaea, implying dispersal. Here, we describe primitive amphisbaenians from the North American Palaeocene, including the oldest known amphisbaenian, and provide new and older molecular divergence estimates for the clade, showing that worm lizards originated in North America, then radiated and dispersed in the Palaeogene following the Cretaceous-Palaeogene (K-Pg) extinction. This scenario implies at least three trans-oceanic dispersals: from North America to Europe, from North America to Africa and from Africa to South America. Amphisbaenians provide a striking case study in biogeography, suggesting that the role of continental drift in biogeography may be overstated. Instead, these patterns support Darwin and Wallace's hypothesis that the geographical ranges of modern clades result from dispersal, including oceanic rafting. Mass extinctions may facilitate dispersal events by eliminating competitors and predators that would otherwise hinder establishment of dispersing populations, removing biotic barriers to dispersal.

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Section: Resultsmentioning

confidence: 79%

Section: Resultsmentioning

confidence: 92%

Biogeography of worm lizards (Amphisbaenia) driven by end-Cretaceous mass extinction

et al. 2015

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“…Blanus is apparently unique in retaining an additional calcified (although not ossified) pelvic element. Furthermore, Blanus and Bipes both retain internal rudiments of the hindlimb skeleton, whereas these are lacking in other amphisbaenians (41,43). The presence of similar variability in the apparently vestigial lateral digits of alvarezsaurid dinosaurs is thus not surprising.…”

Section: Description and Comparisonsmentioning

confidence: 84%

A monodactyl nonavian dinosaur and the complex evolution of the alvarezsauroid hand

Sullivan

Pittman

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Digital reduction is a striking evolutionary phenomenon that is clearly exemplified in theropod dinosaurs by the functionally didactyl manus of tyrannosaurids, the flight-adapted manus of birds (Aves), and the tridactyl but digit II-dominated manus of alvarezsauroids. The enlargement of manual digit II in alvarezsauroids and the concurrent reduction of the lateral digits have been interpreted as adaptations for digging, although no detailed biomechanical analysis of hand function has so far been carried out for this group. In the derived alvarezsauroid clade Parvicursorinae, the lateral digits are so small as to be presumably vestigial. Here we report a new alvarezsauroid, Linhenykus monodactylus gen. et sp. nov., based on a specimen from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China. Cladistic analysis identifies Linhenykus as the most basal parvicursorine, and digit II of the manus retains a slender morphology and other primitive features. However, Linhenykus is also highly apomorphic in exhibiting the most extreme reduction of the lateral manual digits seen in any alvarezsauroid. Phalanges are retained only on the most medial digit (digit II), making Linhenykus the only known functionally monodactyl nonavian dinosaur. Other parvicursorines are more primitive in retaining a tridactyl manus but more derived in that digit II is highly robust and shows other apomorphic features in both of its phalanges. The unexpected combination of features seen in the hand of Linhenykus points to a complex mosaic pattern of manual evolution in alvarezsauroids, with loss of the presumably vestigial outer digits being decoupled from change in the form of digit II.

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“…Species of Leposternon Wagler, 1824, Aulura Barbour, 1914 and Amphisbaena, the most frequent items in the diet of A. scytale, are highly specialized for a fossorial life (ZUG 1993, KEARNEY & STUART 2004) and forage on the soil surface during the night, according to KEARNEY (2003). This fact, added to the records of Caecilia cf.…”

Section: Discussionmentioning

confidence: 99%

Food habits of Anilius scytale (Serpentes: Aniliidae) in the Brazilian Amazonia

Maschio

Prudente

Rodrigues

et al. 2010

Zoologia (Curitiba, Impr.)

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Information on the diet of Anilius scytale is provided based on the analysis of 162 specimens from the Brazilian Amazonia. Amphisbaenians (Aulura anomala Barbour, 1914; Leposternon polystegumn [Duméril, 1951] and Amphisbaena sp.), which are highly specialized for a fossorial life, accounted for 81.25% of the recorded items, followed by snakes - Anilius scytale (Linnaeus, 1758), and Tantilla melanocephala (Linnaeus, 1758): 12.5% - and caecilians - Caecilia cf. gracilis Shaw, 1802: 6.25%. We found a positive, although not significant, relationship between the snout-vent length of A. scytale and the total length of the prey and a tendency for smaller specimens to ingest proportionately larger prey. Anilius scytale forages mainly on the ground, at night, as well as in aquatic environments. The non-selective capture of either proportionately large or small prey by A. scytale may reflect the opportunistic nature of the encounters. A tendency of the juveniles of this species to ingest proportionately larger prey may be associated with either a low availability of prey with a size compatible to that of the juveniles, or with their inexperience in selecting prey. Ingestion of prey headfirst may be an attempt to minimize the risk of injury the prey could cause through their rigid, pointed and sharp structures or powerful bites

show abstract

Repeated evolution of limblessness and digging heads in worm lizards revealed by DNA from old bones

Cited by 125 publications

References 29 publications

Biogeography of worm lizards (Amphisbaenia) driven by end-Cretaceous mass extinction

Biogeography of worm lizards (Amphisbaenia) driven by end-Cretaceous mass extinction

A monodactyl nonavian dinosaur and the complex evolution of the alvarezsauroid hand

Food habits of Anilius scytale (Serpentes: Aniliidae) in the Brazilian Amazonia

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