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Maurel M.-C.,CNRS Systematics, Biodiversity and Evolution Institute | Leclerc F.,University Paris - Sud
Elements | Year: 2016

Systems consisting of mineral surfaces, water, salts and organic molecules are considered to be plausible models of early Earth's prebiotic environments. The probable involvement of clays, highly soluble minerals, sulfides and other minerals at the beginning of life have spurred a number of experimental studies to investigate organic molecule adsorption, polymerization and catalytic reactions of relevance to prebiotic chemistry. This article reviews current ideas in how life originated, summarises experimental results and presents some of the existing challenges that still beset the field of the origins of life.


Klingenberg C.P.,University of Manchester | Gidaszewski N.A.,University of Manchester | Gidaszewski N.A.,CNRS Systematics, Biodiversity and Evolution Institute
Systematic Biology | Year: 2010

The relationship between morphometrics and phylogenetic analysis has long been controversial. Here we propose an approach that is based on mapping morphometric traits onto phylogenies derived from other data and thus avoids the pitfalls encountered by previous studies. This method treats shape as a single, multidimensional character. We propose a test for the presence of a phylogenetic signal in morphometric data, which simulates the null hypothesis of the complete absence of phylogenetic structure by permutation of the shape data among the terminal taxa. We also propose 2 measures of the fit of morphometric data to the phylogeny that are direct extensions of the consistency index and retention index used in traditional cladistics. We apply these methods to a small study of the evolution of wing shape in the Drosophila melanogaster subgroup, for which a very strongly supported phylogeny is available. This case study reveals a significant phylogenetic signal and a relatively low degree of homoplasy. Despite the low homoplasy, the shortest tree computed from landmark data on wing shape is inconsistent with the well-supported phylogenetic tree from molecular data, underscoring that morphometric data may not provide reliable information for inferring phylogeny.


Moreno-Mateos D.,University of California at Berkeley | Moreno-Mateos D.,Stanford University | Power M.E.,University of California at Berkeley | Comin F.A.,CSIC - Pyrenean Institute of Ecology | Yockteng R.,CNRS Systematics, Biodiversity and Evolution Institute
PLoS Biology | Year: 2012

Wetlands are among the most productive and economically valuable ecosystems in the world. However, because of human activities, over half of the wetland ecosystems existing in North America, Europe, Australia, and China in the early 20th century have been lost. Ecological restoration to recover critical ecosystem services has been widely attempted, but the degree of actual recovery of ecosystem functioning and structure from these efforts remains uncertain. Our results from a meta-analysis of 621 wetland sites from throughout the world show that even a century after restoration efforts, biological structure (driven mostly by plant assemblages), and biogeochemical functioning (driven primarily by the storage of carbon in wetland soils), remained on average 26% and 23% lower, respectively, than in reference sites. Either recovery has been very slow, or postdisturbance systems have moved towards alternative states that differ from reference conditions. We also found significant effects of environmental settings on the rate and degree of recovery. Large wetland areas (>100 ha) and wetlands restored in warm (temperate and tropical) climates recovered more rapidly than smaller wetlands and wetlands restored in cold climates. Also, wetlands experiencing more (riverine and tidal) hydrologic exchange recovered more rapidly than depressional wetlands. Restoration performance is limited: current restoration practice fails to recover original levels of wetland ecosystem functions, even after many decades. If restoration as currently practiced is used to justify further degradation, global loss of wetland ecosystem function and structure will spread. © 2012 Moreno Mateos et al.


Buyck B.,CNRS Systematics, Biodiversity and Evolution Institute
Cryptogamie, Mycologie | Year: 2014

This paper explores the interesting diversity within the group of "smooth chanterelles" and introduces several new taxa from the tropics: C. sublaevis Buyck & Eyssart. and C. cibarioides (Heinem.) Buyck comb. nov. from Africa, C. eccentricus Buyck & V. Hofstetter and C. neocaledonicus Buyck, V. Hofstetter, Eyssart. & Ducousso from New Caledonia and C. incrassatus Buyck & V. Hofstetter from Malaysia. © 2014 Adac. Tous droits réservés.


Nattier R.,CNRS Systematics, Biodiversity and Evolution Institute
PloS one | Year: 2012

Islands are bounded areas where high endemism is explained either by allopatric speciation through the fragmentation of the limited amount of space available, or by sympatric speciation and accumulation of daughter species. Most empirical evidence point out the dominant action of allopatric speciation. We evaluate this general view by looking at a case study where sympatric speciation is suspected. We analyse the mode, tempo and geography of speciation in Agnotecous, a cricket genus endemic to New Caledonia showing a generalized pattern of sympatry between species making sympatric speciation plausible. We obtained five mitochondrial and five nuclear markers (6.8 kb) from 37 taxa corresponding to 17 of the 21 known extant species of Agnotecous, and including several localities per species, and we conducted phylogenetic and dating analyses. Our results suggest that the diversification of Agnotecous occurred mostly through allopatric speciation in the last 10 Myr. Highly microendemic species are the most recent ones (<2 Myr) and current sympatry is due to secondary range expansion after allopatric speciation. Species distribution should then be viewed as a highly dynamic process and extreme microendemism only as a temporary situation. We discuss these results considering the influence of climatic changes combined with intricate soil diversity and mountain topography. A complex interplay between these factors could have permitted repeated speciation events and range expansion.


Judson M.L.I.,CNRS Systematics, Biodiversity and Evolution Institute
Palaeontology | Year: 2012

The middle Devonian (Givetian-Eifelian) pseudoscorpion Dracochela deprehendor Schawaller, Shear and Bonamo is redescribed from the type material and an additional palpal fragment. Dracochela differs from extant pseudoscorpions in having numerous spinules on the leg tarsi, the femur at least as long as the patella on the posterior legs, the stem of the arolia thick, most blades of the serrulae only weakly fused and in lacking a spinneret on the chelicera. The blades of the cheliceral rallum are shown to have been arranged in two rows, as in most Heterosphyronida. The cheliceral serrulae are compared with analogous structures in other arachnids (Notostigmata, Opiliones, Palpigradi, Schizomida and Scorpiones), and it is concluded that the panctenal state (all lamellae attached to finger) is plesiomorphic relative to the hemictenal state (apical lamellae raised), which has evolved independently in Heterosphyronida and Neobisioidea. The trichobothriotaxy of the chela of Dracochela is shown to be similar to that of the extant family Pseudotyrannochthoniidae. The growth of the chelal fingers followed the same pattern as that seen in modern pseudoscorpions, with most of the increase in length occurring at the base of the fingers. The family Dracochelidae Schawaller, Shear and Bonamo is treated as a plesion and assigned to the stem-group of Pseudoscorpiones. The ordinal name Chelonethi Thorell is restricted to crown-group pseudoscorpions, and the superordinal name Pseudoscorpiones Latreille is adopted for the total-group (i.e. stem-group plus Chelonethi). © The Palaeontological Association.


Buyck B.,CNRS Systematics, Biodiversity and Evolution Institute
Cryptogamie, Mycologie | Year: 2012

Cantharellus addaiensis is redescribed, illustrated and neotypified. Epitypes are introduced for C. platyphyllus, C. symoensii, C. splendens and C. heinemanniamis. © 2012 Adac.


Grandcolas P.,CNRS Systematics, Biodiversity and Evolution Institute | Nattier R.,CNRS Systematics, Biodiversity and Evolution Institute | Trewick S.,Massey University
Trends in Ecology and Evolution | Year: 2014

Relict species have always beguiled evolutionary biologists and biogeographers, who often view them as fascinating 'living fossils' or remnants of old times. Consequently, they are believed to provide interesting and important information on a vanished past and are used to understand the evolution of clades and biotas. The information that relicts provide can, however, be misleading and overemphasised when it is not remembered that they belong to groups or biotas that are mostly extinct. For example, relict species imply regional extinctions and, for this reason, they cannot simultaneously provide evidence of local biota permanence. Here we consider carefully misconceptions about relict species and highlight more clearly their evolutionary and biogeographical significance. © 2014 Elsevier Ltd.


Selosse M.-A.,CNRS Systematics, Biodiversity and Evolution Institute | Bessis A.,French Institute of Health and Medical Research | Pozo M.J.,CSIC - Experimental Station of El Zaidín
Trends in Microbiology | Year: 2014

The functional similarity between root and gut microbiota, both contributing to the nutrition and protection of the host, is often overlooked. A central mechanism for efficient protection against pathogens is defense priming, the preconditioning of immunity induced by microbial colonization after germination or birth. Microbiota have been recruited several times in evolution as developmental signals for immunity maturation. Because there is no evidence that microbial signals are more relevant than endogenous ones, we propose a neutral scenario for the evolution of this dependency: any hypothetic endogenous signal can be lost because microbial colonization, reliably occurring at germination or birth, can substitute for it, and without either positive selection or the acquisition of new functions. Dependency of development on symbiotic signals can thus evolve by contingent irreversibility. © 2014 Elsevier Ltd.


Bardat J.,CNRS Systematics, Biodiversity and Evolution Institute
Cryptogamie, Bryologie | Year: 2013

Seven mosses, Erpodium biseriatum, Floribundaria pseudofloribunda, Leptodictyum riparium, Macromitrium serpens, Rhodobryum aubertii, Sematophyllum phoeniceum, Trichostomum brachydontium, and one liverwort Lepidozia flexuosa, are new for the New Caledonian flora following identification of some gatherings made in 2008 and herbarium specimens at PC and REN. In addition, new localities have been found for three species of mosses recently discovered in the Territory, Anomodon pseudotristis, Calymperes motlei, Euptychium piliferum and two new synonyms are given for Paris nomina nuda, the moss Vesicularia compienei (= V. subfuscescens) and the liverwort Lepidozia etesseana (= Telaranea kogiana). Moreover two doubtful names of the recent checklist of liverworts are rejected after examination of specimens cited from New Caledonia, Lepidozia supradecomposita and Telaranea lawesii and the data of Zoopsis liukiuensis in New Caledonia earlier than its first publication is reported. In spite of the relatively numerous data dealing with it, the knowledge of bryophyte flora in New Caledonia will increase and be clarified by sampling many widely overlooked areas (for example dry forests) and biotopes and re-examination of herbarium collections. © 2013 Adac. Tous droits réservés.

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