Research ArticleEVOLUTIONARY BIOLOGY

A Triassic-Jurassic window into the evolution of Lepidoptera

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Science Advances  10 Jan 2018:
Vol. 4, no. 1, e1701568
DOI: 10.1126/sciadv.1701568
  • Fig. 1 Lepidopteran scales in palynological preparations, as seen in transmitted light.

    (A) Serrated scale from the Hettangian [316.70 m below surface (mbs)]. (B) Scale with a rounded apical margin from the Rhaetian (337.50 mbs). Scale bars, 20 μm.

  • Fig. 2 Quantitative record of selected form species of gymnosperm pollen in the Schandelah-1 core and stratigraphic position of insect (wing) scales.

    Lepidopteran and unidentified scales are present at the top of the Arnstadt Formation (Rhaetian) between 337.50 and 336.80 mbs and in the basal layers of the Lias Alpha-1 Formation (Hettangian) between 317.90 and 316.40 mbs (see Materials and Methods).

  • Fig. 3 SEM images of scales from the basal Hettangian.

    (A) Lepidopteran type I scale with solid structure and herringbone pattern. (B to E) Lepidopteran type II scales with hollow structure, cross-ridges, perforations, and in some cases (C to E) serrations of the apical margin. (F) Fringed scale of indeterminate origin. (G) Histological section of type I scale. (H and I) Histological sections of type II scales.

  • Fig. 4 Detailed SEM images of selected scales shown in Fig. 3.

    Labeling same as in Fig. 3. (A) Detail of a type I scale showing herringbone pattern. (B) Detail of a type II scale showing oblique crests at the apical margin. (C to E) Type II scales showing hollow structure, perforations, cross-ridges, and microribs (arrows in Fig. 3, C and D). (F) Detail of a fringed scale of indeterminate origin showing distinct apical margin.

  • Table 1 Comparative overview of principal morphological and structural scale characteristics.

    (A) Scales of scale-bearing hexapod lineages examined in this study (for details, see the Supplementary Materials). (B) Distinctive Rhaetian-Hettangian lepidopteran scale types. “-”, absence of a trait; “?”, uncertainty regarding presence/absence or interpretation of a trait.

    GroupApical marginCross ridgesMicroribsStructurePerforationsHerringbone pattern
    A
    CollembolaRounded--Solid--
    ArchaeognathaRoundedFar apart, rectangular cells-HollowYes-
    ZygentomaRoundedIndistinct, irregular-Solid--
    PsocopteraRounded--Solid--
    ColeopteraRounded--Hollow--
    TrichopteraRounded--HollowSome-
    CulicidaeRoundedModerately dense-Solid--
    BerothidaeRounded?????
    KalligrammatidaeRounded?????
    MicropterigidaeRoundedDenseYes?Solid-Dense
    EriocranidaeRoundedDenseYesSolid--
    CoelolepidaSerrated/roundedDenseYesHollowYes-
    B
    HerringboneRounded?-Solid-Dense–moderately dense
    HollowSerrated/roundedDensePresentHollowSmall, between cross ridges-

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/1/e1701568/DC1

    Supplementary Text: Comparative scale morphology

    fig. S1. SEM images of scales of Collembola and Archaeognatha.

    fig. S2. SEM images of scales of Zygentoma and Psocoptera.

    fig. S3. SEM images of scales of non-coelolepidan Lepidoptera.

    fig. S4. SEM images of scales of coelolepidan Lepidoptera.

    fig. S5. SEM images of scales of Culicidae.

    References (4958)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Text: Comparative scale morphology
    • fig. S1. SEM images of scales of Collembola and Archaeognatha.
    • fig. S2. SEM images of scales of Zygentoma and Psocoptera.
    • fig. S3. SEM images of scales of non-coelolepidan Lepidoptera.
    • fig. S4. SEM images of scales of coelolepidan Lepidoptera.
    • fig. S5. SEM images of scales of Culicidae.
    • References (49–58)

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