Maps showing the fossil locality at Jiahua village, Tiantai County, Zhejiang, East China.

<p>The maps are created by CorelDRAW X8 (<a href="http://www.coreldraw.com/en/product/graphic-design-software/" target="_blank">http://www.coreldraw.com/en/product/graphic-design-software/</a>).</p

Bract epidermis of fossil and living <i>Pseudolarix amabilis</i>.

<p>(A–C) Fossil cuticle. (A) Adaxial cuticle showing the arrangement of epidermal cells and stomata. (B) Inner surface of the stomatal apparatus showing the monocyclic subsidiary cells. (C) Abaxial cuticle showing the rectangular epidermal cells. (D–F) Cuticle of extant species for comparison. (D) Adaxial epidermal cells and stomata. (E) Stomatal apparatus. (F) Abaxial epidermal cells. Scale bars: (A, C, D, F), 40 μm; (B, E), 20 μm.</p

Late Miocene <i>Pseudolarix amabilis</i> bract-scale complex from Zhejiang, East China

<div><p>Previously, the identification of fossil <i>Pseudolarix</i> at the species level has been based on the morphology of the bract-scale complex of the seed cone. The morphological consistence of fossils through most of the Cenozoic with extant <i>P</i>. <i>amabilis</i> has led them to be considered conspecific, suggesting that <i>P</i>. <i>amabilis</i> is an extraordinary example of morphological stasis. However, the lack of cuticular evidence, especially for the leaf-homologous bract, reduces the accuracy of fossil identification based on morphology, thus weakening the evidence for morphological stasis in <i>P</i>. <i>amabilis</i>. For the first time, we provide cuticular evidence of the bract-scale of fossil <i>P</i>. <i>amabilis</i> based on the bract-scale complex from the late Miocene Shengxian Formation, Zhejiang, East China, which improves the identification accuracy and reinforces the concept of morphological stasis in this species. Second, we preliminarily reveal the niche stability of <i>P</i>. <i>amabilis</i>, which corresponds to its morphological stasis. Finally, we infer that the late Miocene forest containing <i>P</i>. <i>amabilis</i> in Zhejiang was an evergreen sclerophyllous broad-leaved or mixed mesophytic forest, which combined with the evergreen broad-leaved forest suggested by previous megafossil studies, indicates the occurrence of vertical vegetation zonation.</p></div

Ovuliferous scale epidermis of fossil and living <i>Pseudolarix amabilis</i>.

<p>(A–C, H) Abaxial fossil cuticle. (A) Cuticle of the upper half of the ovuliferous scale showing the arrangement of epidermal cells and stomata. (B) Outer surface of the cuticle showing the sunken stomatal apparatus. (C) Inner surface of the cuticle showing the cuticular projection resulting from the sunken stomatal apparatus. (D-G, I) Abaxial epidermis of extant species for comparison. (D) Epidermis of the upper half of the ovuliferous scale. (E) Outer surface of the sunken stomatal apparatus. (F) Cuticular projection on the inner surface of the cuticle. (G) Cuticle with epidermal cells attached with arrowhead 1 pointing to the stoma, arrowhead 2 pointing to the epidermal cell, and arrowhead 3 pointing to the cuticle. (H) Cuticle of the auriculate parts of the fossil ovuliferous scale with the approximate isodiametric polygon epidermis cells indicated by an arrowhead. (I) Cuticle at the base of the auriculate parts of the extant ovuliferous scale. Scale bars: (A, D, G, I), 40 μm; (B, C, E, F), 10 μm; (H), 100 μm.</p

MAT requirements for the survival of <i>Pseudolarix amabilis</i> compared with global climate over the Cenozoic.

<p>(A) Global benthic δ¹⁸O record (modified from Zachos et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180979#pone.0180979.ref007" target="_blank">7</a>]). (B) MAT requirements of <i>P</i>. <i>amabilis</i> at different time slices during the Cenozoic (for details, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180979#pone.0180979.t001" target="_blank">Table 1</a>). The dashed line shows the linear trend in the median required MAT values.</p

The MAT requirements of <i>Pseudolarix amabilis</i> through geological time^a.

<p>The MAT requirements of <i>Pseudolarix amabilis</i> through geological time<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180979#t001fn001" target="_blank">^a</a>.</p

The worldwide distribution of fossil and living <i>Pseudolarix</i>.

<p>Fossil records are updated based on LePage and Basinger [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180979#pone.0180979.ref005" target="_blank">5</a>]; for updated fossil records, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180979#pone.0180979.s001" target="_blank">S1 Table</a>. Living distribution data are accessed through Chinese Virtual Herbarium (CVH) Data Portal (<a href="http://www.cvh.ac.cn/" target="_blank">http://www.cvh.ac.cn/</a>) (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180979#pone.0180979.s002" target="_blank">S2 Table</a>). The map is generated by ArcGis v. 9.3 (<a href="http://www.arcgis.com/home/index.html" target="_blank">http://www.arcgis.com/home/index.html</a>).</p

Reconstruction of fossil <i>Pseudolarix amabilis</i>.

<p>(A) Abaxial surface of the bract-scale complex. (B) Adaxial surface of the ovuliferous scale. Panels (A, B) were drawn by Aili Li. Scale bars: (A, B), 1 cm.</p