A new large philisid (Mammalia,Chiroptera, Vespertilionoidea) from the late Early Eocene of Chambi,Tunisia

Abstract: Among the new dental remains from the late Early Eocene of Chambi (Kasserine area, Tunisia) is a large‐sized upper molar of a new bat species, Witwatia sigei nov. sp. (Chiroptera, Vespertilionoidea, Philisidae), described herein. The locality of Chambi has revealed evidence for an early appearance of two modern microchiropteran superfamilies in Africa: Dizzya exsultans, a Philisidae, which is considered to be an archaic Vespertilionoidea, and an indeterminate Rhinolophoidea. In addition to D. exsultans, the new species, W. sigei, is the second representative of the Philisidae in this locality. W. sigei extends back to the late Early Eocene the occurrence of the genus Witwatia, which was previously only reported from the early Late Eocene of the Fayum (BQ‐2, Egypt). By analogy with the largest extant microbats, the large size of Witwatia suggests a tendency to the opportunistic diet of this taxon, thereby contrasting with the strict insectivory characterizing primitive bats found in other continents in the same epoch.     

A NEW SPECIES OF MOERITHERIUM (PROBOSCIDEA, MAMMALIA) FROM THE EOCENE OF ALGERIA: NEW PERSPECTIVES ON THE ANCESTRAL MORPHOTYPE OF THE GENUS

Abstract:  A new species of Moeritherium (Proboscidea, Mammalia), M. chehbeurameuri sp. nov., is described from remains discovered in the early late Eocene locality of Bir El Ater, Algeria. Although mainly represented by isolated teeth, it shows distinct synapomorphies which justify its attribution to the genus Moeritherium , together with exclusive features that led to the creation of the new species. The main characteristic of this new taxon is the almost complete lophodonty shown by its molars, while Moeritherium is commonly regarded as a bunolophodont to bunodont taxon. In addition to this lophodonty, this new taxon shows anatomical features as yet unknown for the genus, but often met within lophodont early proboscidean taxa such as Phosphatherium escuilliei and Numidotherium koholense . Although a revision of the whole genus Moeritherium is outside the scope of this paper, the main controversies and discussion about the definition of species within the genus Moeritherium are discussed. The surprising lophodonty of M. chehbeurameuri , together with its small size, its early late Eocene age and the weak molarization of its P₃ support the hypothesis of a lophodont hypothetical ancestor for moeritheres, and therefore strengthen the growing hypothesis of a lophodont dental ancestral morphotype for proboscideans.     

Molecular Phylogeny and Biogeography of the Genus Ilex L. (Aquifoliaceae)

The chloroplast atpB-rbcL spacer was sequenced for 115 speciesof Ilex and forNemopanthus mucronatus (Aquifoliaceae). In addition,rbcL sequences were obtained for 47 selected species. Takentogether with fossil records in the literature, the data indicatethat: (1) the lineage Ilex was already cosmopolitan long beforethe end of the Cretaceous. A relative test of the rate of nucleotidesubstitution indicates that extant species do not representthe entire lineage because of the extinction of its basal branches.The common ancestor of the extant species probably appearedat the upper Tertiary. (2) Several Asian/North American disjunctionsare observed, as well as North American/South American relationships.The directions of these relationships are yet to be determined.The African species Ilex mitis is closely related to Asian species.Ilex anomala (Hawaii and Tahiti) is related to American species.Ilex perado and Ilex canariensis (both in Macaronesia) havetotally different relationships, the former being related toEurasian species, while relationships of the latter remain obscure.(3) Gene trees substantially contradict the systematics of Loesener.Nemopanthus,closely related to Ilex amelanchier, is nested in the genusIlex. The family Aquifoliaceae is organized in four groups,each of them having a geographic or ecological peculiarity.Copyright 2000 Annals of Botany Company Aquifoliaceae, chloroplast DNA, fossil record, historical biogeography, Ilex (holly tree), molecular phylogeny.     

Finding candidate genes under positive selection in Non‐model species: examples of genes involved in host specialization in pathogens

Numerous genes in diverse organisms have been shown to be under positive selection, especially genes involved in reproduction, adaptation to contrasting environments, hybrid inviability, and host‐pathogen interactions. Looking for genes under positive selection in pathogens has been a priority in efforts to investigate coevolution dynamics and to develop vaccines or drugs. To elucidate the functions involved in host specialization, here we aimed at identifying candidate sequences that could have evolved under positive selection among closely related pathogens specialized on different hosts. For this goal, we sequenced c. 17 000–32 000 ESTs from each of four Microbotryum species, which are fungal pathogens responsible for anther smut disease on host plants in the Caryophyllaceae. Forty‐two of the 372 predicted orthologous genes showed significant signal of positive selection, which represents a good number of candidate genes for further investigation. Sequencing 16 of these genes in 9 additional Microbotryum species confirmed that they have indeed been rapidly evolving in the pathogen species specialized on different hosts. The genes showing significant signals of positive selection were putatively involved in nutrient uptake from the host, secondary metabolite synthesis and secretion, respiration under stressful conditions and stress response, hyphal growth and differentiation, and regulation of expression by other genes. Many of these genes had transmembrane domains and may therefore also be involved in pathogen recognition by the host. Our approach thus revealed fruitful and should be feasible for many non‐model organisms for which candidate genes for diversifying selection are needed.     

New stem elephant‐shrews (Mammalia,Macroscelidea) from the Eocene of Dur At‐Talah,Libya

Abstract: Two new primitive macroscelideans, Eotmantsoius perseverans gen. et sp. nov. and Nementchatherium rathbuni sp. nov. from the late Middle or Late Eocene locality of Dur At‐Talah, Libya, are described. Eotmantsoius is known from a single tooth and is characterized by low crown height, isolated conules, and lack of a preprotocrista and prehypocrista. Based on these characters, it appears to be more plesiomorphic than Chambius (late Early Eocene, Chambi, Tunisia), which was, to date, universally accepted as the oldest and most basal macroscelidean. Eotmantsoius appears, however, somewhat derived in having an entostyle, a pericone, a shorter mesial cingulum and larger intercusp valleys. The phylogenetic position of Eotmantsoius is unclear. The second new species, N. rathbuni, allows a reassessment of Nementchatherium. We suggest that it is the most derived of the herodotiines in having long preprotocrista and prehypocrista, reduced M2/m2, a robust entostyle twinned with the hypocone on M1 and the posterior aspect of the root of the maxillary jugal process placed along the length of M2. Nementchatherium rathbuni appears more derived than N. senarhense, from the Eocene locality of Bir El Ater, Algeria, in having smaller m2‐3 with no paraconid, a smaller hypoconulid on m2 and a more reduced talonid on m3 (with smaller hypoconid and entoconid). Nementchatherium rathbuni also has, distal to the m3, a coronoid canal. This character has commonly been proposed as a synapomorphy for paenungulates (e.g. proboscideans, sirenians and hyracoids); we investigate the possibility that it unites macroscelideans and paenungulates, as the superordinal clade Afrotheria suggests. Comparisons reveal that a coronoid canal also occurs in several nonafrotherian orders (lagomorphs, xenarthrans, artiodactyls and perissodactyls), suggesting that is not an exclusive synapomorphy for paenungulates plus macroscelideans. Moreover, the homology of the character within paenungulates is doubtful.     

Evolution of the tooth enamel microstructure in the earliest proboscideans (Mammalia)

Microstructural features of the mammalian tooth enamel are rarely used to construct phylogenies, although macromorphological characters of the dentition figure prominently in phylogenetic analysis. In order to test the phylogenetic significance of the enamel microstructures, we investigate here the earliest proboscideans recently found in the Early Palaeogene of Africa (e.g. Phosphatherium , Daouitherium , Khamsaconus , and Numidotherium ). The results are discussed in the light of the recent advances concerning the intra- and interordinal relationships of the Proboscidea. We also consider other basal paenungulates such as 'anthracobunids', embrithopods, and hyraxes. The analysed microstructures suggest that the enamel ancestral morphotype of paenungulates was primitive for eutherian mammals, consisting in radial enamel. Some basal proboscideans developed decussations of prisms in Hunter-Schreger bands (HSB), as did most of the medium to large-sized mammals. More evolved proboscideans developed very complex enamel, the 3-D enamel, which represents an apomorphy for the group. The three-layered Schmelzmuster, typical of the elephantoids (3-D enamel, HSB, and radial enamel), is acquired during the late Eocene with the enigmatic ' Numidotherium ' savagei . This species is here considered as an advanced proboscidean along with Moeritherium -Deinotheriidae-Elephantiformes. The peculiar enamel of elephantoids arose step by step. Although homoplasy and mosaic evolution occur, the enamel microstructures represent an important source of new dental characters for phylogenetic reconstructions. As macromorphological characters testified, the diversity of the enamel microstructures observed in the various basal proboscideans illustrates an unexpected early diversity of the order in Africa.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 149 , 611–628.     

Phylogenetic relationships of wild silkmoths (Lepidoptera: Saturniidae) inferred from four protein-coding nuclear genes

Abstract.  The Saturniidae, or wild silkmoths, number approximately 1861 species in 162 genera and nine subfamilies including Cercophaninae and Oxyteninae. They include some of the largest and most spectacular of all Lepidoptera, such as the moon or luna moths, atlas moths, emperor moths, and many others. Saturniids have been important as sources of wild silk and/or human food in a number of cultures, and as models for comparative studies of genetics, development, physiology, and ecology. Seeking to improve the phylogenetic framework for such studies, we estimated relationships across Saturniidae, sampling all nine subfamilies plus all five tribes of Saturniinae. Seventy-five exemplars (45 Saturniidae plus 30 bombycoid outgroups) were sequenced for four protein-coding nuclear gene regions (5625 bp total), namely CAD (the fusion protein carbamoylphosphate synthetase/aspartate transcarbamylase/dihydroorotase), DDC (dopa decarboxylase), period, and wingless. The data, analyzed by parsimony and likelihood, gave a strongly resolved phylogeny at all levels. Relationships among subfamilies largely mirrored the pre-cladistic hypothesis of Michener, albeit with significant exceptions, and there was definitive support for the morphology-based proposal that Ludiinae form a tribe (Micragonini) within Saturniinae. In the latter subfamily, the African tribe Urotini was shown to be paraphyletic with respect to Bunaeini and Micragonini, also in accord with recent morphological findings. Relationships within the New World subfamilies Arsenurinae, Ceratocampinae and Hemileucinae nearly always accord with previous morphology-based phylogenies when both are clearly resolved. Within Hemileucinae, Hemileucini are paraphyletic with respect to the monotypic Polythysanini. A preliminary biogeographical analysis supports ancestral restriction to the New World, followed by dispersal and/or vicariance splitting most of the family into a largely New World versus a largely Old World clade.