Lorsque le bois vient au secours de l'identification : exemple sur deux Menispermaceae

During a phytochimic study on Menispermaceae, the wood samples of Coscinum fenestratum (Gaertn.) Colebr. and Arcangelisia flava (L.) Merr. were mixed. I undertook a wood anatomy study in order to identify them. Arcangelisa flava shows successive cambium. The size of the sample (more than 3.5 cm in diameter) allows us to certifiy that the lack of successive cambia is not due to a sufficiently large sample. The idea, proposed by some authors, that all Menispermaceae have successive cambia is therefore rejected. Thanks to this knowledge of wood anatomy, the sample could be correctly identifed and analysed.Au cours d'une étude phytochimique sur les Menispermaceae, les échantillons de bois de Coscinium fenestratum (Gaertn.) Colebr. et Arcangelisia flava (L.) Merr. ont été mélangés. J'ai entrepris une étude anatomique pour pouvoir les identifier. Arcangelisia flava présente des cambiums successifs, ce qui est le type classique décrit pour les Menispermaceae. Coscinium fenestratum n'a pas de cambiums successifs. La taille de l'échantillon (plus de 3,5 cm de diamètre) permet de certifier que cette absence de cambiums successifs n'est pas due à une taille trop petite de l'échantillon. L'idée, proposée par certains auteurs, que toutes les Menispermaceae auraient des cambiums successifs est donc rejetée. Grâce à la connaissance de l'anatomie du bois, les échantillons ont pu être correctement identifiés et analysés.Jacques Frédéric M.B. Lorsque le bois vient au secours de l'identification : exemple sur deux Menispermaceae. In: Bulletin mensuel de la Société linnéenne de Lyon, 75ᵉ année, n°8, octobre 2006. pp. 297-299

Histoire évolutive des Menispermaceae

La famille des Menispermaceae (Ranunculales) comporte environ 510 espèces décrites. Ce travail propose une description détaillée de nombreux endocarpes de la famille, montrant la diversité des formes existantes. Une étude anatomique classe le bois de cette famille en deux grands types : avec ou sans cambiums successifs. Une analyse morphologique cladistique distingue deux grands groupes de Menispermaceae, les Tinosporioideae et les Menispermoideae, auxquels s'ajoutent les Peniantheae et Burasaia. Ce sont les organes reproducteurs qui apportent l'information phylogénétique la plus fiable. Aucune phylogénie moléculaire fiable n'a été obtenue avec les gènes rbcL et atpB. Il semble saturé en mutations chez les Menispermaceae. Dix nouvelles espèces et un nouveau genre fossiles sont décrits. La liste complète des espèces fossiles de la famille est fournie avec une interprétation paléogéographique. Une analyse phylogéographique propose des centres de diversification pour chacun des clades.The Menispermaceae family (Ranunculales) includes about 510 described species. The present work gives a precise description of numeours endocarps of the family, showing the existing shapes diveristy. An anatomical study classifies the wood of the family in two major types: with or without successive cambia. A cladistic morphological analysis discriminates two important groups of Menispermaceae, the Tinosporoideae and the Menispermoideae, to which the Peniantheae and Burasaia are added. The reproductive organs give the most reliable phylogenetic information. No reliable molecular phylogeny was obtained with rbcL gene. This gene seems saturated in mutations by the Menispermaceae. Ten new fossil species and one new fossil genus are described. The complete list of Menispermaceae fossil species and its paleogeographic interpretation are given. A phylogeographic analysis assigns diversification centers for each clade.PARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF

Histoire évolutive des Menispermaceae

La famille des Menispermaceae (Ranunculales) comporte environ 510 espèces décrites. Ce travail propose une description détaillée de nombreux endocarpes de la famille, montrant la diversité des formes existantes. Une étude anatomique classe le bois de cette famille en deux grands types : avec ou sans cambiums successifs. Une analyse morphologique cladistique distingue deux grands groupes de Menispermaceae, les Tinosporioideae et les Menispermoideae, auxquels s'ajoutent les Peniantheae et Burasaia. Ce sont les organes reproducteurs qui apportent l'information phylogénétique la plus fiable. Aucune phylogénie moléculaire fiable n'a été obtenue avec les gènes rbcL et atpB. Il semble saturé en mutations chez les Menispermaceae. Dix nouvelles espèces et un nouveau genre fossiles sont décrits. La liste complète des espèces fossiles de la famille est fournie avec une interprétation paléogéographique. Une analyse phylogéographique propose des centres de diversification pour chacun des clades.The Menispermaceae family (Ranunculales) includes about 510 described species. The present work gives a precise description of numeours endocarps of the family, showing the existing shapes diveristy. An anatomical study classifies the wood of the family in two major types: with or without successive cambia. A cladistic morphological analysis discriminates two important groups of Menispermaceae, the Tinosporoideae and the Menispermoideae, to which the Peniantheae and Burasaia are added. The reproductive organs give the most reliable phylogenetic information. No reliable molecular phylogeny was obtained with rbcL gene. This gene seems saturated in mutations by the Menispermaceae. Ten new fossil species and one new fossil genus are described. The complete list of Menispermaceae fossil species and its paleogeographic interpretation are given. A phylogeographic analysis assigns diversification centers for each clade.PARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF

Revised Taxonomy of Selected Fossil Endocarp Species in the Menispermaceae Using a Morphometric Approach

Several Cenozoic endocarp remains from the northern hemisphere have been described with strong affinities to either Menispermum L. or Sinomenium Diels, a monophyletic group of menispermous vines. It has been proposed that all of these fossil species are synonymous and should be included within Sinomenium. In order to evaluate this suggestion, we have studied the morphological variation ranges in the menispermous endocarps with geometric morphometrics, and then the ranges of the selected fossil endocarps is compared to the ranges of modern endocarps. The shape of each endocarp is described using eight landmarks and 17 semilandmarks, accounting for the outline and the positions of lateral ridge and foramen on the endocarps. Endocarp ornamentation is studied by statistical comparisons of the number of transverse ridges. It is concluded that the ranges of variation within the fossil genera, all morphologically related to horseshoe-shaped endocarps in Menispermaceae, are found not to be greater than that in the only extant species of Sinomenium, S. acutum (Thunb.) Rehder & Wilson. Sinomenium macrocarpum Liu & Jacques, 2010 differs from the other fossil species of Sinomenium by its higher number of transverse ridges. All other fossil species of Sinomenium, except S. macrocarpum, and Wardensheppeya Eyde, 1970 are synonymous. Menispermum? taylori Chandler, 1964 is transferred to Sinomenium. The fossil genus Palaeosinomenium Chandler, 1961 is confirmed through the obliquity of its endocarp, but all species are found to be synonymous. Menispermicarpum rariforme Chandler, 1961 is also included in Palaeosinomenium

First Discovery of Cucubalus (Caryophyllaceae) Fossil, and Its Biogeographical and Ecological Implications

A new species of Cucubalus is described based on two fossil seeds recovered from the upper Pliocene Sanying Formation in northwestern Yunnan Province, southwestern China. The seeds are characterized by a reniform to circular outline in shape, and sinuous and discontinuous rugulae made of rod-like elements radiating from the hilum region to the dorsal margin. The combination of these characteristics shows their close resemblance to the extant genus Cucubalus in the Caryophyllaceae. A morphological principal coordinates (PCO) analysis further supports the assignment to this genus. Cucubalus is a monotypic genus today, but the late Pliocene fossil seeds have been described as a new species, Cucubalus prebaccifer Huang, Liu et Zhou, sp. nov. This newly documented Cucubalus fossil, representing the first fossil record of this genus, implies that the genus has existed in northwestern Yunnan, southwestern China, at least since the late Pliocene. It provides important information on the past biodiversity and biogeography of both the genus Cucubalus and the fossil-scant family Caryophyllaceae

Quantitative Climate Reconstructions of the Late Miocene Xiaolongtan Megaflora from Yunnan, Southwest China

The late Miocene Xiaolongtan megaflora from Kaiyuan in southeast Yunnan (23°48′45″N, 103°11′52″E, 1050 m a.s.l.) was chosen for palaeoclimatic reconstruction using three quantitative techniques, i.e. the Coexistence Approach (CA), Leaf Margin Analysis (LMA), and the Climate-Leaf Analysis Multivariate Program (CLAMP). The reconstructed climatic parameters are also compared with those of the two adjacent Miocene floras currently available in Yunnan, i.e. the early to middle Miocene carpological Mangdan flora (24°24′N, 97°49′E, 1620 m a.s.l.) and the late Miocene Lühe palynoflora (25°10′N, 101°22′E, 1930 m a.s.l.). Quantitative analyses of the Xiaolongtan flora supports the previous qualitative results of a southern, humid subtropical climate, being more humid and having a slightly higher mean annual temperature (MAT) than today. The MATs calculated by CA, LMA, and CLAMP overlap (16.7-19.2 °C, 22.3 ± 2.05 °C, 18.1 ± 1.2 °C, respectively) and are close to the present day value (19.7 °C). The overlapping of temperatures derived using the three techniques is unusual and probably related to the low latitude of the Xiaolongtan area and the southern subtropical nature of its vegetation. Both the mean temperatures of the warmest month (WMT) and of the coldest month (CMT) reconstructed by CA (WMT = 25.4-26.0 °C, CMT = 7.7-8.7 °C) and CLAMP (WMT = 25.9 ± 1.6 °C, CMT = 10.8 ± 1.9 °C) are similar to those of today (WMT = 24.3 °C, CMT = 12.8 °C), but great changes appear in the mean annual precipitation (MAP). The CLAMP results suggest a higher precipitation (1964 ± 335.9 mm) than CA (1215-1639 mm), but they are much higher than the present MAP (820.5 mm). This is consistent with results from the Lühe palynoflora, which also developed under a warmer subtropical climate with higher precipitation (803.6-1254.7 mm) than that of today (815.9 mm). In contrast, the Mangdan flora, situated in a more complicated topographic region to the west of Xiaolongtan and near the Sino-Myanmar border, implies a slightly lower precipitation (1170-1300 mm) than that of today (1300-1400 mm). Overall, the wetter climate during the late Miocene around the Xiaolongtan area suggests that the Himalayas had not yet uplifted to its present altitudes at that time

New Fossil Endocarps of Sambucus (Adoxaceae) From the Upper Pliocene in SW China

A new species of fossil endocarp is described from the Sanying Formation of the upper Pliocene at Fudong Village, Lanping County of northwestern Yunnan Province, Southwest China. The endocarps are elliptic, ovate or oblong elliptic, 2.1-2.5. mm long and 1.2-1.7. mm wide. The dorsal face is convex and the ventral is concave or more flattened. The endocarp surface is loosely, transversely or sinuously furrowed and ridged, forming a reticulate and alveolate pattern on the ridges, and the inner wall of the surface cells on the ridges is flaky and scaly. They are morphologically compared with selected extant genera of Adoxaceae and Caprifoliaceae. The interspecific comparisons show diagnostic differences of the fossil endocarps from the selected modern species and other fossil taxa, supporting their recognition as a new species: Sambucus alveolatisemina Huang, Liu et Zhou, sp. nov. Previous records of the reliable Sambucus fossils were from mid-high latitude regions in Europe, northeastern Asia and northern North America. Therefore, it is interesting to note that S. alveolatisemina represents a fossil record from a low latitude region. Sambucus apparently has existed at low latitudes in China at least since the upper Pliocene. A review of other Sambucus fossil occurrences indicates that plants of this genus have been living at higher latitudes in the geological past than they are at present

A New Drynaria (Polypodiaceae) From the Upper Pliocene of Southwest China

A polypodiaceous fern, Drynaria callispora sp. nov., is described from the upper Pliocene Sanying Formation in western Yunnan Province, southwestern China. This species with well-preserved pinnae and in situ spores is the first convincing Drynaria fossil record. Detailed morphological investigation reveals that D. callispora is characterized by 1) pinnatifid fronds with entire-margined pinnae having straight or zigzag secondary veins; 2) finer venation showing void quadrangular areoles, but occasionally with one unbranched veinlet; 3) one row of circular sori on each side of the strong primary vein; and 4) in situ spores with verrucate exospores elliptical in polar view and bean-shaped in equatorial view. A morphological comparison shows that D. callispora is significantly different from all the fossil species previously identified as drynarioids. A phylogenetic analysis of D. callispora supports that the fossil is closely related to D. sinica Diels and D. mollis Bedd., two extant species distributing in the Himalayas. The discovery of the new fern indicates that the genus Drynaria became diversified in its modern distribution region no later than the late Pliocene and had retained a similar ecology to that of many modern drynarioid ferns ever since

The Intensification of the East Asian Winter Monsoon Contributed to the Disappearance of Cedrus (Pinaceae) in Southwestern China

Climate change during the Quaternary played an important role in the distribution of extant plants. Herein, cone scales of Cedrus (Pinaceae) were uncovered from the Upper Pliocene Sanying Formation, Longmen Village, Yongping County of Yunnan Province in southwestern China. Detailed comparisons show that these fossils all belong to the genus Cedrus (Pinaceae), and a new species is proposed, Cedrus angusta sp. nov. This find expands the known distribution of Cedrus during the Late Pliocene to Yunnan, where the genus no longer exists in natural forests. Based on the analysis of reconstructed Neogene climate data, we suggest that the intensification of the East Asian winter monsoon during the Quaternary may have dramatically increased seasonality and given rise to a much drier winter in Yunnan. Combined with information on Cedrus fossil records and its seed physiology, we conclude that the intensification of a drier climate after the Late Pliocene may have prevented the survival of Cedrus seedlings, leading to the eventual disappearance of Cedrus in western Yunnan. This study indicates that the topography in southwestern China acted as a vital refuge for many plants during the Quaternary, but that other species gradually disappeared due to the intensification of the monsoonal climate