A New Species of Rhodoleia (Hamamelidaceae) from the Upper Pliocene of West Yunnan, China and Comments on Phytogeography and Insect Herbivory
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See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/283872586 A New Species of Rhodoleia (Hamamelidaceae) from the Upper Pliocene of West Yunnan, China and Comments on Phytogeography and Insect Herbivory Article in Acta Geologica Sinica · October 2015 DOI: 10.1111/1755-6724.12556 CITATIONS READS 7 190 7 authors, including: Jingyu Wu (Christopher) Yusheng Liu Lanzhou University University of Missouri - Kansas City 43 PUBLICATIONS 627 CITATIONS 87 PUBLICATIONS 2,100 CITATIONS SEE PROFILE SEE PROFILE Sanping Xie Bainian Sun Lanzhou University Lanzhou University 47 PUBLICATIONS 521 CITATIONS 115 PUBLICATIONS 1,921 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Nature and Time on Earth - Project for a course and a book for virtual visits to past environments in learning programmes for university students (coordinators Edoardo Martinetto, Emanuel Tschopp, Robert A. 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Vol. 89 No. 5 pp.1440–1452 ACTA GEOLOGICA SINICA (English Edition) Oct. 2015 A New Species of Rhodoleia (Hamamelidaceae) from the Upper Pliocene of West Yunnan, China and Comments on Phytogeography and Insect Herbivory WU Jingyu1, 2, *, ZHAO Zhenrui1, LI Qijia1, LIU Yusheng (Christopher)3, XIE Sanping1, DING Suting1, 2 and SUN Bainian1, * 1 Key Laboratory of Mineral Resources in Western China (Gansu Province), School of Earth Sciences, Lanzhou University, Lanzhou 730000, China 2 State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, CAS, Nanjing 210008, China 3 Don Sundquist Center of Excellence in Paleontology, Department of Biological Sciences, East Tennessee State University, Box 70703, Johnson City, Tennessee 37614–1710, USA Abstract: In Europe, fossil fruits and seeds of Rhodoleia (Hamamelidaceae) have been described from the Upper Cretaceous to the Miocene, whereas no fossil record of Rhodoleia has been reported in Asia, where the modern species occur. Herein, 21 fossil leaves identified as Rhodoleia tengchongensis sp. nov. are described from the Upper Pliocene of Tengchong County, Yunnan Province, Southwest China. The fossils exhibit elliptic lamina with entire margins, simple brochidodromous major secondary veins, mixed percurrent intercostal tertiary veins, and looped exterior tertiaries. The leaf cuticle is characterized by pentagonal or hexagonal cells, stellate multicellular trichomes, and paracytic stomata. The combination of leaf architecture and cuticular characteristics suggests that the fossil leaves should be classified into the genus Rhodoleia. The fossil distributions indicate that the genus Rhodoleia might originate from Central Europe, and that migrated to Asia prior to the Late Pliocene. Additionally, insect damage is investigated, and different types of damage, such as hole feeding, margin feeding, surface feeding, and galling, are observed on the thirteen fossil leaves. Based on the damage frequencies for the fossil and extant leaves, the specific feeding behavior of insects on Rhodoleia trees appears to have been established as early as the Late Pliocene. The high occurrence of Rhodoleia insect herbivory may attract the insect-foraging birds, thereby increasing the probability of pollination. Key words: Rhodoleia, leaf cuticle, phytogeography, insect herbivory, Pliocene, Yunnan Province 1 Introduction (Mai, 2001). Within the family Hamamelidaceae, leaf architecture The genus Rhodoleia Champion ex Hooker is one of 31 and anatomical characteristics are helpful for generic genera in the family Hamamelidaceae. The genus classification (Li and Hickey, 1988; Fang, 1990; Pan et al., comprises 7 species (Exell, 1933) or 9 species (Chang, 1990). In this study, based on a detailed comparison of 1973) of evergreen trees or shrubs distributed in South leaf architecture and cuticular features, 21 fossil leaves China, Vietnam, Thailand, Myanmar, Malaysia, Sumatra, from the Upper Pliocene in Yunnan Province are and Indonesia (Zhang et al., 2003). The fossil fruits and identified as Rhodoleia tengchongensis sp. nov. The seeds of several species of Rhodoleia are known in Europe discovery of this new species from Southwest China, as from the Upper Cretaceous to the Miocene (Mai and the only leaf record of Rhodoleia to date, not only Walther, 1985; Knobloch and Mai, 1986; Mai, 1987, provides a valuable opportunity for revealing the leaf 2001). However, no any fossil record of Rhodoleia has architecture and cuticular differences between Pliocene been documented in Asia, and no fossil leaves, wood or fossils and extant species but also improves our pollen have thus far been found elsewhere in the world understanding of the phytogeography of this genus and the * Corresponding author. E-mail: [email protected] (J.Y. Wu); [email protected] (B.N. Sun) © 2015 Geological Society of China Oct. 2015 ACTA GEOLOGICA SINICA (English Edition) Vol. 89 No. 5 1441 http://www.geojournals.cn/dzxben/ch/index.aspx http://mc.manuscriptcentral.com/ags Pliocene climate of Southwest China. (Shi et al., 2012) and deposition rate (Li and Xue, 1999; Plant-insect interactions have dominated terrestrial Sun et al., 2012), the fossil-bearing deposits studied are ecosystems for over 420 million years (Labandeira, 2006; undoubtedly of the Late Pliocene (3.3–2.8 Ma). Wilf, 2008; Na et al., 2014). The remains of insect feedings on fossil plants have been widely investigated 3 Material and Methods throughout the Phanerozoic (e.g., Chaloner et al., 1991; Banerji, 2004; Wilf et al., 2005; Prevec et al., 2009), and it The extant leaves for comparison were collected from is generally accepted that insect damage on fossil leaves Kunming and Pingbian of Yunnan Province, Guangzhou can provide abundant information regarding terrestrial of Guangdong Province, and Haikou of Hainan Province. food webs (Wilf and Labandeira, 1999; Labandeira, 2006; To study the leaf architecture, the extant leaves were Carvalho et al., 2014; Donovan et al., 2014). In the present cleared with a 10% solution of NaOH. The experimental paper, the insect damage type and frequency are compared treatments used for the fossil and extant cuticles are well between Rhodoleia fossil and extant leaves, and the described in previous studies (Dao et al., 2013; He et al., specialist herbivores for this genus are discussed. 2014). The fossil cuticles were embedded in paraffin and cut using a Leica RM2255 microtome. The terminology 2 Geological Setting for leaf architecture follows Manual of Leaf Architecture (Ellis et al., 2009), and the foliar cuticle terminology is The fossil leaves were collected from an open-cast that of Dilcher (1974) and Wilkinson (1979). The insect diatomite mine ca. 1 km west of Tuantian Town (24° 41′ damage types are according to Labandeira et al. (2007). N, 98° 38′ E; Fig. 1a), Tengchong County, Yunnan The estimation of the leaf dry mass per area (MA) for Province, Southwest China. The fossil-bearing diatomites the fossil leaves is according to the formula of Royer et al. 2 belong to the Upper Pliocene Mangbang Formation (Fig. (2007): lg[MA] =3.070+0.382×lg[PW /A], where MA is the 1b) which is subdivided into three lithologic units (Ge and leaf dry mass per area (g m–2), PW is the petiole width Li, 1999; Shang, 2003; Li et al., 2004; Sun et al., 2004). (mm), and A is the leaf area (mm2). Based on SHRIMP zircon U-Pb dating of volcanic rocks All fossil specimens, cuticle slides and SEM stubs are Fig. 1. Distribution map of Rhodoleia and stratigraphic section of the fossil location. a, The geographic map of fossil site and extant distributions. b, The stratigraphic section through the Mangbang Formation in Tengchong County, Yunnan Province, China (after Ge and Li, 1999; Shang, 2003; Li et al., 2004; Sun et al., 2004). 1442 Vol. 89 No. 5 ACTA GEOLOGICA SINICA (English Edition) Oct. 2015 http://www.geojournals.cn/dzxben/ch/index.aspx http://mc.manuscriptcentral.com/ags stored at the Institute of Palaeontology and Stratigraphy, and decurrent attachment to midvein. Interior and minor Lanzhou University, Gansu Province, China. secondaries absent. Intersecondaries span more than 50% of the length of the subjacent secondary, occuring at less 4 Systematics and Comparison than one per intercostal area; proximal course is parallel to major secondaries, and distal course perpendicular to a 4.1 Systematics subjacent major secondary (Fig. 2a–i). Intercostal tertiary Order Hamamelidales Griseb. veins mixed percurrent with obtuse angle to midvein and Family Hamamelidaceae R. Brown inconsistent vein angle variability (Fig. 2j, k). Exterior Genus Rhodoleia Champion ex Hooker tertiaries looped (Fig. 2j). Quaternary vein fabric irregular Rhodoleia tengchongensis J.Y. Wu et B.N. Sun sp. reticulate. Areolation shows moderate development. nov. Freely ending veinlets mostly with two or more branches Holotype: FTP–553A (Fig. 2e; Fig. 4c) (Fig. 2j, k). Marginal ultimate venation looped (Fig. 2j). Paratypes: FTP–010A (Fig. 2a, j, k; Fig. 4e, g), FTP– Leaves hypostomatic: Adaxial epidermis ca. 9 μm 010B (Fig. 2b), FTP–315–6 (Fig. 2c), FTP–309–6 (Fig. 2i; thick; cells isodiametric, pentagonal or hexagonal, and 11– Fig. 3c, d; Fig. 4f, h, k, l), FTP–281 (Fig. 2f; Fig. 3b), FTP 25 μm long and 9–18 μm wide; anticlinal cell walls –323–1 (Fig. 2d; Fig. a; Fig. 4a, b, i), FTP–14009 (Fig. straight and developing into a honeycomb, periclinal walls 2g), FTP–14065 (Fig. 2h). smooth (Fig. 3a, c; Fig. 4a). Abaxial epidermis ca. 8 μm Other specimens: FTP–553B, FTP–14016, FTP– thick; cells isodiametric, pentagonal or hexagonal, 12–27 14034, FTP–091, FTP–317–23, FTP–232, FTP–310, FTP μm long and 8–20 μm wide, and each cell covered by a –307–5, FTP–543, FTP–225–21, FTP–504, FTP–135, papilla on the outer wall (Fig. 4b-d); anticlinal walls FTP–304–27, FTP–226–16. straight and honeycombed (Fig. 4a). Stomatal apparatus Type locality: Tuantian Town (N 24° 41′, E 98° 38′), paracytic, randomly orientated and slightly sunk (Fig.