Research ArticlePALEONTOLOGY

Unexpected Early Triassic marine ecosystem and the rise of the Modern evolutionary fauna

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Science Advances  15 Feb 2017:
Vol. 3, no. 2, e1602159
DOI: 10.1126/sciadv.1602159
  • Fig. 1 Chronostratigraphic subdivisions of the Early Triassic [radiometric ages from studies by Galfetti et al. (5), Ovtcharova et al. (47), Ovtcharova et al. (48), and Burgess et al. (49)] with simplified global geochemical trends [δ13Ccarb data from Galfetti et al. (5); anoxic episodes modified following studies by Grasby et al. (6), Galfetti et al. (50), Ware et al. (51), and Hermann et al. (52)] and the relative temperature fluctuations in the Tethyan realm [adapted from studies by Sun et al. (2) and Romano et al. (3)].

    Subdivisions of the Smithian and Spathian follow the ammonoid zonation from studies by Brühwiler et al. (53) and Guex et al. (54). The late Smithian extinction event is highlighted in red. Time correlations for the late Smithian and the Smithian-Spathian boundary are based on high-resolution ammonoid zonations (20, 55, 56). A, Anasibirites beds; X, Xenoceltitidae beds (both late Smithian); T, Tirolites beds (early Spathian); ea., early; mi., middle; l., late; VPBD, Vienna Pee Dee belemnite.

  • Fig. 2 Maps showing the location of the newly discovered Paris Biota.

    (A) Present-day map showing the location of southeastern Idaho in western United States. (B) Map of southeastern Idaho showing the location of the Paris Biota. (C) Early Triassic map with the location of the Paris Biota. (A) to (C) were modified following the study by Romano et al. (57).

  • Fig. 3 Simplified stratigraphic log showing main Early Triassic fossil-bearing levels currently known in the Bear Lake area.

    Fossil occurrence is modified following the study by Romano et al. (57), with additional data from studies by Massare and Callaway (58) (ichthyosaur remains), Tosk and Andersson (59) (foraminifers), and Hofmann et al. (60) and from our own field observations (black stars). Conodonts are also sparsely present throughout the section but are not represented here. Stratigraphy follows the main units defined by Kummel (61, 62). Zonation is based on ammonoids (20, 54, 55, 62, 63). Position of the Paris Biota is highlighted in red. A U-Pb age of 250.55 ± 0.4 My is associated with the Tirolites/Columbites beds from South China (5). LL, Lower Limestone; LS, Lower Shale; ML, Middle Limestone; MS, Middle Shale; UCS, Upper Calcareous Siltstone; Meek, Meekoceras beds; Anasib, Anasibirites beds; Tirol, Tirolites beds; Colum, Columbites beds.

  • Fig. 4 Characteristic earliest Spathian organisms of the Paris Biota.

    (A) Leptomitid protomonaxonid sponge (s) and ammonoids (a) (slab IMNH IP-026/777). (B) Leptomitid protomonaxonid sponge showing a twisted apex and minute epizoan brachiopods (arrows) (slab UBGD 30505). (C) Glyphidean lobster Litogaster ?turnbullensis (UBGD 30548). (D) New thylacocephalan genus (UBGD 30561). (E) Penaeid shrimp (IMNH IP-026/778). (F) Caridean shrimp under ultraviolet (UV) light (365 nm) (UBGD 30558). (G) Gladius-bearing coleoid (UBGD 30545). (H) Holocrinid crinoid stem with cirri (UBGD 30563). (I) Ophiuroid (UBGD 30565). Scale bars, 5 mm (A and C to I) and 10 mm (B). [Photo credits: A. Brayard, Université Bourgogne Franche-Comté (A to G); T. Saucède, Université Bourgogne Franche-Comté (H); and B. Thuy, Natural History Museum Luxembourg (I).]

  • Fig. 5 Specimens and characteristic features of leptomitid protomonaxonid sponges from the Paris Biota.

    (A and B) General and closeup view of the specimen UBGD 30504 showing projected longitudinal spicules (ls) from the apex forming a fringe of marginalia (m) and transverse spicules (ts). (C and D) Closeup views of twisted apex (ta) of two specimens (UBGD 30505 and 30581) under natural and UV light (365 nm). Projecting spicules from the apex forming a fringe of marginalia are also visible. Fine transverse spicules appear mainly as wrinkles, perpendicular to the longitudinal spicules. An epizoan brachiopod (e) is attached to the sponge specimen C. (E and F) Closeup views of specimens UBGD 30506 and 30508, showing longitudinal and transverse spicules. (G and H) Large-sized specimens UBGD 30510 and 30511. Scale bars, 5 mm (A to D and G and H), 2 mm (E), and 1 mm (I). [Photo credits: A. Brayard, Université Bourgogne Franche-Comté.]

  • Fig. 6 Characteristic earliest Spathian organisms of the Paris Biota.

    (A and B) Belemnoid arm hooks (UBGD 30540 and 30544). (C) Penaeid shrimp (UBGD 30559). (D to F) Mass accumulations of caridean shrimps under UV light (365 nm) and natural light (slabs UBGD 30553 and 30554). (G) Rod-shaped, unbranched specimens of putative noncalcified dasycladales (slab UBGD 30576). (H) Isolated arms of a holocrinid crinoid (UBGD 30563). (I) Chondrichthyan tooth referable to Acrodus (slab IMNH 1143/46168). (J) Osteichthyan tooth plate (slab UBGD 30569). (K) Coprolite specimen (UBGD 30573). (L) Closeup view of belemnoid hooks accumulated in a coprolite (slab UBGD 30575). (M) Discinoid inarticulate brachiopod Orbiculoidea sp. (UBGD 30522). Scale bars, 5 mm (A to K and M) and 0.5 mm (L). [Photo credits: A. Brayard, Université Bourgogne Franche-Comté (A to H and J to M); L. J. Krumenacker, Montana State University (I).]

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/2/e1602159/DC1

    Supplementary Text

    fig. S1. Field view of the upper part of the Lower Shale unit containing the Paris Biota.

    fig. S2. Log section of the main Paris Biota exposure.

    fig. S3. Taxa of the Paris Biota showing unexpected or extended temporal distributions, new Early Triassic spatiotemporal occurrences, new oldest records of derived characters for the clade, and new ecologic or trophic interactions.

    fig. S4. Artistic reconstruction of the Paris Biota.

    fig. S5. Closeup view of an apex of a leptomitid protomonaxonid sponge.

    fig. S6. Closeup views of twisted apex of two leptomitid protomonaxonid sponges.

    fig. S7. Closeup views of longitudinal and transverse spicules of four leptomitid protomonaxonid sponges.

    figs. S8 to S10. Leptomitid protomonaxonid sponges from the Paris Biota.

    fig. S11. Leptomitid protomonaxonid sponge from the Paris Biota showing attachment to a shell fragment.

    fig. S12. Linguloid and discinoid inarticulate brachiopods.

    fig. S13. Sponge specimen showing minute epizoan brachiopods and closeup views of epizoan brachiopods.

    fig. S14. Bivalve specimens.

    fig. S15. Ammonoid and nautiloid specimens.

    fig. S16. Belemnoid arm hooks.

    fig. S17. Gladius-bearing coleoid.

    fig. S18. Different types of preservation for crustaceans from the Paris Biota.

    fig. S19. Penaeidean and caridean shrimps and accumulations.

    fig. S20. Penaeid shrimps, caridean shrimp, and litogastrid lobsters.

    fig. S21. Thylacocephalan specimens.

    fig. S22. Holocrinid specimens.

    fig. S23. Closeup view of a crinoid stem with cirri and closeup view of an isolated pinnulate arm.

    fig. S24. Ophiuroid specimens.

    fig. S25. Closeup view of the spine articulations of an ophiuroid specimen.

    fig. S26. Vertebrate remains from the Paris Biota.

    fig. S27. Coprolites from the Paris Biota.

    fig. S28. Algal morphotypes from the Paris Biota.

    fig. S29 and S30. SEM photographs and EDS analyses for leptomitid protomonaxonid sponge specimens.

    fig. S31. SEM photograph and EDS analysis for a crustacean specimen.

    fig. S32. SEM photograph and EDS analysis for a belemnoid hook specimen.

    fig. S33. SEM photograph and EDS analyses for a leptomitid protomonaxonid sponge specimen.

    table S1. Sampled taxa from the Paris Biota.

    References (64134)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Text
    • fig. S1. Field view of the upper part of the Lower Shale unit containing the Paris Biota.
    • fig. S2. Log section of the main Paris Biota exposure.
    • fig. S3. Taxa of the Paris Biota showing unexpected or extended temporal distributions, new Early Triassic spatiotemporal occurrences, new oldest records of derived characters for the clade, and new ecologic or trophic interactions.
    • fig. S4. Artistic reconstruction of the Paris Biota.
    • fig. S5. Closeup view of an apex of a leptomitid protomonaxonid sponge.
    • fig. S6. Closeup views of twisted apex of two leptomitid protomonaxonid sponges.
    • fig. S7. Closeup views of longitudinal and transverse spicules of four leptomitid protomonaxonid sponges.
    • figs. S8 to S10. Leptomitid protomonaxonid sponges from the Paris Biota.
    • fig. S11. Leptomitid protomonaxonid sponge from the Paris Biota showing attachment to a shell fragment.
    • fig. S12. Linguloid and discinoid inarticulate brachiopods.
    • fig. S13. Sponge specimen showing minute epizoan brachiopods and closeup views of epizoan brachiopods.
    • fig. S14. Bivalve specimens.
    • fig. S15. Ammonoid and nautiloid specimens.
    • fig. S16. Belemnoid arm hooks.
    • fig. S17. Gladius-bearing coleoid.
    • fig. S18. Different types of preservation for crustaceans from the Paris Biota.
    • fig. S19. Penaeidean and caridean shrimps and accumulations.
    • fig. S20. Penaeid shrimps, caridean shrimp, and litogastrid lobsters.
    • fig. S21. Thylacocephalan specimens.
    • fig. S22. Holocrinid specimens.
    • fig. S23. Closeup view of a crinoid stem with cirri and closeup view of an isolated pinnulate arm.
    • fig. S24. Ophiuroid specimens.
    • fig. S25. Closeup view of the spine articulations of an ophiuroid specimen.
    • fig. S26. Vertebrate remains from the Paris Biota.
    • fig. S27. Coprolites from the Paris Biota.
    • fig. S28. Algal morphotypes from the Paris Biota.
    • figs. S29 and S30. SEM photographs and EDS analyses for leptomitid protomonaxonid sponge specimens.
    • fig. S31. SEM photograph and EDS analysis for a crustacean specimen.
    • fig. S32. SEM photograph and EDS analysis for a belemnoid hook specimen.
    • fig. S33. SEM photograph and EDS analyses for a leptomitid protomonaxonid sponge specimen.
    • table S1. Sampled taxa from the Paris Biota.
    • References (64–134)

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