Research ArticlePALEONTOLOGY

A mid-Cretaceous embryonic-to-neonate snake in amber from Myanmar

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Science Advances  18 Jul 2018:
Vol. 4, no. 7, eaat5042
DOI: 10.1126/sciadv.aat5042
  • Fig. 1 Overview of amber clast with synchrotron x-ray μCT image of articulated snake skeleton (DIP-S-0907).

    (A) Amber clast with included skeletal material. (B) Dorsal view of skeleton, synchrotron x-ray micro–computed tomography (μCT) image. (C) Ventral view of skeleton, synchrotron x-ray μCT image. Scale bar, 10 mm.

  • Fig. 2 Details of skeletal elements of Xiaophis myanmarensis (DIP-S-0907) and vertebral element of neonate of extant Cylindrophis ruffus (colorized light yellow for contrast with fossil material in gray).

    (A to K) X. myanmarensis. (L to Q) C. ruffus. (A) CT image of dorsal view of mid-precloacal vertebrae, anterior to left. (A) Light photograph of the dorsal view of mid-precloacal vertebrae, anterior to left. (C) CT image of left lateral view of mid-precloacal vertebrae, anterior to left. (D) CT image of the ventral view of mid-precloacal vertebrae, anterior to left. (E) CT image of the left lateral view showing the articulating haemal spine. (F) CT image of the right lateral view of caudal vertebrae showing the articulating haemal spine. (G to K) CT renderings of isolated precloacal vertebrae of X. myanmarensis (DIP-S-0907) in dorsal view (G), left lateral view (H), ventral view (I), anterior view (J), and posterior view (K). (L to Q) CT renderings of isolated precloacal vertebrae of neonate C. ruffus. (L) Dorsal view. (M) Left lateral view. (N) Ventral view. (O) Anterior view. (P) Right dorsolateral view. (Q) Posterodorsal view. ac, accessory process; cn, condyle; ct, cotyle; hk, haemal keel; h-sp, haemal spine; na-g, neural arch groove; ns-ep, neural spine epiphyseal pit; sf, subcentral formina; zyg?, incipient zygantrum; zys?, incipient zygosphene.

  • Fig. 3 High-definition CT images of neonate vertebral column of C. ruffus (colorized light yellow for contrast with fossil material in gray) compared to X. myanmarensis.

    Cross-sectional views through precloacal vertebrae of (A) C. ruffus, anterolateral view (note the incipient formation of zygosphenial joint as small nubs on neural arch lamina facing into small facets of posterior arch portion of more anterior vertebra in partial section) and (B) X. myanmarensis at level of zygosphene tectum, anterolateral view. Sagittal sections through precloacal vertebral series of (C) C. ruffus, anterior to right [note the presence of soft but distinct zygantral facets on posterior and internal surface of neural arch, and open notochordal canals (no-ca) and distinct ossification of cotyle-condyle (ct-cn) portions of bony centra at joints] and (D) X. myanmarensis, anterior to right [note that neural canal (nc) and notochordal canals are infilled with permineralized material of similar density, although spaces are obvious in both canals; density and histology of bone at cotyle-condyle joints differs from permineralized infilling material; cotyle-condyle bone–forming joints are similar to that observed in neonate of C. ruffus (C)].

  • Fig. 4 Light photographs of probable snake shed skin (DIP-V-15104).

    (A) Overall view of the complete specimen. Scale bar, 5 mm. (B) Close-up of the left portion of the specimen showing converging scale rows (center top). Scale bar, 1 mm. (C) Close-up of the right mid-region of the specimen. Scale bar, 1 mm.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/7/eaat5042/DC1

    Supplementary Text

    Fig. S1. High-definition x-ray μCT image of holotype skeleton (DIP-S-0907).

    Fig. S2. High-definition x-ray μCT images of holotype skeleton (DIP-S-0907).

    Fig. S3. Probable sacral ribs, right dorsolateral view, x-ray μCT image of holotype.

    Fig. S4. Precloacal vertebrae of X. myanmarensis and other snakes.

    Fig. S5. Scales of and second-scale specimen.

    Fig. S6. Mid-sagittal sections through posterior precloacal vertebrae of two juvenile snakes.

    Fig. S7. Distribution of Late Jurassic (Barremian)–Late Cretaceous (Maastrichtian) snakes represented on a map of Cenomanian arrangement of land masses.

    Fig. S8. Strict consensus of 2040 equally parsimonious trees.

    Data file S1. Data matrix for phylogenetic analysis: Nexus file format.

    References (3393)

  • Supplementary Materials

    The PDF file includes:

    • Supplementary Text
    • Fig. S1. High-definition x-ray μCT image of holotype skeleton (DIP-S-0907).
    • Fig. S2. High-definition x-ray μCT images of holotype skeleton (DIP-S-0907).
    • Fig. S3. Probable sacral ribs, right dorsolateral view, x-ray μCT image of holotype.
    • Fig. S4. Precloacal vertebrae of X. myanmarensis and other snakes.
    • Fig. S5. Scales of and second-scale specimen.
    • Fig. S6. Mid-sagittal sections through posterior precloacal vertebrae of two juvenile snakes.
    • Fig. S7. Distribution of Late Jurassic (Barremian)–Late Cretaceous (Maastrichtian) snakes represented on a map of Cenomanian arrangement of land masses.
    • Fig. S8. Strict consensus of 2040 equally parsimonious trees.
    • References (3393)

    Download PDF

    Other Supplementary Material for this manuscript includes the following:

    • Data file S1. Data matrix for phylogenetic analysis: Nexus file format.

    Files in this Data Supplement:

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