A tale of two clades: Comparative study of Glyptodon Owen and Glyptotherium Osborn (Xenarthra,Cingulata, Glyptodontidae)

Glyptodon and Glyptotherium represent the most conspicuous taxa of late Neogene and Pleistocene glyptodonts in South America and North America, respectively. The earliest records of Glyptodon in South America are 1.07 Ma (late early Pleistocene, Calabrian), although the possibility that “Paraglyptodon uquiensis” represents a Pliocene specimen of Glyptodon cannot be rejected. Glyptotherium originated from South American ancestry in northern South America or Central America about 3.9 Ma (early late Pliocene, Zanclean) or earlier. The diversity of South American Glyptodon is currently under study, but preliminary evidence would indicate that no more than three species (G. munizi, G. elongatus and G. reticulatus) are valid, plus a possible new Andean species. In turn, according to the updated taxonomy proposed herein, Glyptotherium includes two chronospecies. The earliest species, Gl. texanum, differs only slightly from the latest species, Gl. cylindricum. The relationship of Glyptodon and Glyptotherium has been problematical since the discovery of the North American lineage, at first identified as various species of Glyptodon and later considered a separate genus. Glyptodon is recognized as a natural group and recent taxonomic and phylogenetic revisions place all North American glyptodontines into Glyptotherium. In this paper, we propose a detailed morphological comparison between the southern South American species of Glyptodon and Glyptotherium in order to identify diagnostic differences and potential synapomorphies. Both genera can be distinguished mainly by differences in the skull, mandible, dentition, dorsal carapace, and caudal armor, Glyptodon being somewhat larger than Glyptotherium. Both clades show a highly conservative evolution, which could be interpreted as an anagenesis. The scarce records of glyptodonts in Central America show more morphological affinity with Glyptotherium than with Glyptodon.     

A new species of Panochthus Burmeister (Xenarthra,Cingulata, Glyptodontidae) from the Pleistocene of the Eastern Cordillera,Bolivia

Panochthus and Glyptodon are the Pleistocene Glyptodontidae having the greatest range of latitudinal distribution and elevation in South America. The most recent revisions of Panochthus recognized its high taxonomic diversification mainly distributed in the Chaco-Pampean region of Argentina, Uruguay, southern Bolivia and southern and north-eastern Brazil, while the Andean records are poorly known. This contribution aims: (a) to describe a new species of Panochthus from the Pleistocene of the surroundings of Potosi (Bolivia), which represents one of the highest known elevation records for fossil Xenarthra; (b) to carry out a phylogenetic analysis in order to test its location in Panochthus and relationship to some allied genera; (c) to discuss some palaeobiogeographical and morphological implications. The results show that, in agreement with previous studies, Panochthus is a natural group, being Propanochthus the sister taxa. This conclusion agrees, at least in part, with the original interpretation of Burmeister, who recognized Pr. bullifer as belonging to Panochthus. The genera Nopachtus and Phlyctaenopyga are more closely related to some ‘Plohophorini’ than to the clade Propanochthus + Panochthus. Within Panochthus, this new species occupies a relatively basal position as a sister taxon of the clade composed of P. tuberculatus, P. intermedius, and P. greslebini.http://zoobank.org/lsid:zoobank.org:pub:5A766550-DBCA-4C4A-BDB8-602E500E4954     

Sussemionus, a new subgenus of Equus (Perissodactyla,Mammalia)

The new subgenus of Equus, Sussemionus, is defined by peculiar dental characters so far unknown, or exceptional in late Pleistocene and extant Equus; it was in consequence assumed to be restricted to the early and middle Pleistocene. During that period, it was highly successful, ranging from North America to Ethiopia, and included dry-adapted (E. granatensis-like) and more humid-adapted (E. coliemensis-like) species. Recent molecular and osteological analyses concurred to prove its survival until ca 45 KYBP in Khakassia, southwest Siberia, Russia.     

Late Miocene Microstonyx remains (Suidae, Mammalia) from Northern China

Several large suid cranial remains attributed to Microstonyx major are part of a new Hipparion Fauna collection from the Hezheng area, Northern China. The new material confirms the presence of Microstonyx in the late Miocene of the area. The Chinese form belongs to a small-sized eastern population with reduced premolar row and clear sexual bimodality. Statistical comparison shows that Microstonyx major was a polymorphic species and reinforces recognition of Hippopotamodon as a separate genus, defined by relatively stout premolars resulting from a different underlying pattern of allometric growth. The presence of Microstonyx in North China and the distinct suid assemblage that lived there suggest biogeographic connections between Northern China and Western Eurasia in contrast to isolation from Southern China and the Indian subcontinent. The suid fauna of the late Miocene of Northern China seems to have been restricted to the later, more humid phase represented by the Red Clay faunas.     

An exceptional Pleistocene specimen of Panochthus Burmeister (Xenarthra, Glyptodontoidea) from Bolivia: Its contribution to the understanding of the Early-Middle Pleistocene Panochthini

Knowledge of the Early-Middle Pleistocene (Ensenadan Age/Stage ; ca. 1.8-0.4 Ma) South American Glyptodontidae (Cingulata) is still poor compared with the Late Pleistocene-Early Holocene taxa (Lujanian Age/Stage). This is especially true for the Glyptodontidae Panochthini, in which it is possible to recognize two Ensenadan species from the Pampean region of Argentina, Panochthus intermedius and P. subintermedius, known only by their type material. Prior to this contribution, the knowledge of P. intermedius, a taxon with biostratigraphic importance for being considered as a guide taxon of the Ensenadan Age/Stage of South America, was limited to a dorsal carapace. The finding of an exceptional almost complete specimen from the Early-Middle Pleistocene of Bolivia has allowed us to greatly improve the morphological characterization of this species, and discuss some taxonomic aspects related to the other Ensenadan Panochthini. This specimen represents the most completely known Panochthini and one of the most complete Glyptodontidae from the Early-Middle Pleistocene of South America.     

Early Pleistocene Dicerorhinus sumatrensis remains from the Liucheng Gigantopithecus Cave, Guangxi, China

The Liucheng Gigantopithecus Cave is very famous for its rich mammalian fauna and Gigantopithecus fossils. The Gigantopithecus Cave Fauna has been regarded as the typical Early Pleistocene fauna in South China. The majority of the fossils unearthed has been studied and published during the past decades. The only group remaining unpublished is the rhinoceros, which is studied in this paper. The rhino materials available today are only mandibles and lower cheek teeth. The dimensions of the tooth rows and the isolated teeth fall well within the range of the recent Dicerorhinus sumatrensis. Therefore, the rhino fossils from the Liucheng Gigantopithecus Cave can be referred to this living species. The reduced lower incisors and the U-shaped lingual contour of the mandible also support this taxonomic determination. The rhino materials from the Liucheng Gigantopithecus Cave represent the earliest known record of this species and the smallest Pleistocene rhinocerotid in China.     

Phylogenetic reassessment of Hyaloscyphaceae sensu lato (Helotiales, Leotiomycetes) based on multigene analyses

Hyaloscyphaceae is the largest family in Helotiales, Leotiomycetes. It is mainly characterized by minute apothecia with well-differentiated hairs, but its taxonomic delimitation and infrafamilial classification remain ambiguous. This study performed molecular phylogenetic analyses using multiple genes including the ITS-5.8S rDNA, the D1–D2 region of large subunit of rDNA, RNA polymerase II subunit 2, and the mitochondrial small subunit. The primary objective was to evaluate the phylogenetic utility of morphological characters traditionally used in the taxonomy of Hyaloscyphaceae through reassessment of the monophyly of this family and its genera. The phylogenetic analyses inferred Hyaloscyphaceae as being a heterogeneous assemblage of a diverse group of fungi and not supported as monophyletic. Among the three tribes of Hyaloscyphaceae only Lachneae formed a monophyletic lineage. The presence of hairs is rejected as a synapomorphy, since morphologically diversified hairs have originated independently during the evolution of Helotiales. The true- and false-subiculum in Arachnopezizeae are hypothesized to have evolved through different evolutionary processes; the true-subiculum is likely the product of a single evolutionary origin, while the false-subiculum is hypothesized to have originated multiple times. Since Hyaloscyphaceae sensu lato was not resolved as monophyletic, Hyaloscyphaceae sensu stricto is redefined and only applied to the genus Hyaloscypha.     

Mycobiota associated with the ambrosia beetle Scolytodes unipunctatus (Coleoptera: Curculionidae, Scolytinae)

Ambrosia beetles (Coleoptera: Scolytinae) are associated with strictly entomochoric and mutualistic fungi. We studied the mycobiota associated with Scolytodes unipunctatus, ambrosia beetles that infest Cecropia trees in Central America. Isolates were characterized using morphology and rDNA sequences (ITS region, LSU, and SSU rDNA). Four species are described here: Raffaelea scolytodis sp. nov. (Ophiostomatales), Gondwanamyces scolytodis sp. nov., Custingophora cecropiae sp. nov., and Graphium sp. (Microascales). The genus Custingophora is emended to include Knoxdaviesia anamorphs of Gondwanamyces based on uniformity of DNA sequences and phenotype.     

Systematics and evolution of the genus Torrubiella (Hypocreales, Ascomycota)

Torrubiella is a genus of arthropod-pathogenic fungi that primarily attacks spiders and scale insects. Based on the morphology of the perithecia, asci, and ascospores, it is classified in Clavicipitaceae s. lat. (Hypocreales), and is considered a close relative of Cordyceps s. 1., which was recently reclassified into three families (Clavicipitaceae s. str., Cordycipitaceae, Ophiocordycipitaceae) and four genera (Cordyceps s. str, Elaphocordyceps, Metacordyceps, and Ophiocordyceps). Torrubiella is distinguished morphologically from Cordyceps s. lat. mainly by the production of superficial perithecia and the absence of a well-developed stipitate stroma. To test and refine evolutionary hypotheses regarding the placement of Torrubiella and its relationship to Cordyceps s. lat., a multi-gene phylogeny was constructed by conducting ML and Bayesian analyses. The monophyly of Torrubiella was rejected by these analyses with species of the genus present in Clavicipitaceae, Cordycipitaceae, and Ophiocordycipitaceae, and often intermixed among species of Cordyceps s. lat. The morphological characters traditionally used to define the genus are, therefore, not phylogenetically informative, with the stipitate stromata being gained and/or lost several times among clavicipitaceous fungi. Two new genera (Conoideocrella, Orbiocrella) are proposed to accommodate two separate lineages of torrubielloid fungi in the Clavicipitaceae s. str. In addition, one species is reclassified in Cordyceps s. str. and three are reclassified in Ophiocordyceps. The phylogenetic importance of anamorphic genera, host affiliation, and stipitate stromata is discussed.     

Aeretesmelanopterus (Pteromyinae, Rodentia) from Tianyuan Cave near Zhoukoudian (Choukoutien) in China

The materials of Aeretesmelanopterus from the Tianyuan Cave, a Late Pleistocene site with human fossils recovered recently near Zhoukoudian, are the richest of this species ever reported in North China. Aeretesmelanopterus is an endemic species of China, its relationship with Petaurista and Trogopterus is still controversal. Studies based on the dental characters show that Aeretesmelanopterus resembles Petaurista more closely than Trogopterus. The earliest fossil record of Aeretesmelanopterus was found in South China in Middle Pleistocene deposits. The earliest records in the Beijing area are from Upper Cave and Tianyuan Cave at Zhoukoudian are of late-Late Pleistocene age, around 30 kyrs BP. The geographical distributions of this species are very limited. In evolution, Aeretesmelanopterus experienced both the increase and the decrease in tooth size; but its crown height of cheek teeth was continuously increasing.     

Structure and development of the style base in Abildgaardia, Bulbostylis, and Fimbristylis (Cyperaceae,Cyperoideae, Abildgaardieae)

The Abildgaardieae tribe within the family Cyperaceae comprises six or seven genera, among which Abildgaardia, Bulbostylis and Fimbristylis pose a challenge regarding their morphological delimitation. Molecular phylogenetic analyses including species of Abildgaardieae are rare, but in most of those studies, Abildgaardia and Fimbristylis appear as more closely related to each other than to the Bulbostylis genus. Duration of the style base has been one of the most widely used characters for delimiting these three genera. The style base is a persistent structure in most species of Bulbostylis and deciduous in Abildgaardia and Fimbristylis. The reasons why the style base may persist or fall off have been scarcely discussed. The assumption that abscission layers are present in the style base of all three genera and the fact that tracheids have been observed in the style base of Bulbostylis suggest that this structure might have histological complexity. In view of this, a complete ontogenetic and anatomical study of the gynoecium has been carried out for all these three genera. It turned out that the style base is histologically simple in Abildgaardia, Bulbostylis and Fimbristylis and shows similar structure and development in all three genera. The fact that the style base has a shorter duration in Abildgaardia and Fimbristylis than in Bulbostylis might be related to the lower number of sclerotised cells that make up such structures in the mature fruit of the former two genera. Abscission of the style and style base may be the result of much simpler reasons than the differentiation of an abscission layer, resulting merely from mechanical shear force effects. Differences among genera have been observed in the shape of the style base and the development of the style. The histological simplicity of the style base is consistent with the homoplastic appearance of this structure in genera that are not closely related (e.g. Rhynchospora). Because of this, while the presence of the thickened style base seems to be a synapomorphy in species of Abildgaardieae, its persistence on or detachment from the fruit might have emerged repeatedly during this clade evolution and might not be a suitable character for genera delimitation.     

Comparative pollen morphology of Brachylena, Tarchananthus and two species of Tubulifloridites (Asteraceae) from the Eocene, Knysna Lignite of South Africa

Two fossil taxa Tubulifloridites antipodica and T. viteauensis recovered from the Eocene Knysna Lignite of South Africa were examined with scanning (SEM) and transmission electron microscopy (TEM). The details of their sculpturing and wall structure are similar to the same species of fossil dispersed pollen taxa recovered from southwestern Africa and South America. Fifteen species of the woody South African taxa, Brachylaena (9 species) and Tarchonanthus (6 species) were investigated with SEM and TEM. All of the taxa are tricolporate, spherical to slightly prolate, microechinate to echinate and have a bilayered columellate infrastructure, except B.ilicifolia, which has a single columellate infrastructural level with the “granularization” of the outer portion of the infrastructural layer or the inner layer of the tectum. There is a similar distribution of plesiomorphic and derived pollen characters in a number of aster subfamilies and tribes suggesting a similar evolutionary progression of pollen, and pollen wall character evolution was occurring synchronously in a variety of aster subfamilies during the middle Tertiary and that these unique pollen features may be important to the evolution and diversification of the Asteraceae.     

Prevalence and seasonality of Ascogregarina culicis (Apicomplexa: Lecudinidae) in natural populations of Aedes aegypti (Diptera: Culicidae) from temperate Argentina

Ascogregarina infections from South America were recently documented in Brazil and Argentina. The aim of this study was to report our recent findings on the prevalence and seasonality of Ascogregarina culicis in Aedes aegypti adults from temperate Argentina. Between December 2003 and May 2005, 391 females of Ae. aegypti were captured in two areas of Greater Buenos Aires. Overall prevalence of A. culicis was 21.2% (83/391), and a significant difference was observed between both areas (28.4% vs. 8%). Infected Ae. aegypti were found from November to May, with highest values in March (24-37%). Parasite prevalence and host abundance showed similar seasonal patterns. Our observations suggest a widespread infestation of A. culicis among Ae. aegypti populations from temperate Argentina.     

Essential oil composition of Achyrocline flaccida (Weinm.) DC. (Asteraceae) from different locations of Argentina

The qualitative and quantitative composition of the essential oils obtained from the inflorescences of Achyrocline flaccida (Asteraceae) has been investigated for the first time. Plant material was collected from eleven locations in Argentina. The essential oils were obtained by hydrodistillation (0.1–0.8% v/w, dried material) and analyzed by GC–FID–MS. Eighty-three compounds were identified representing more than the 90% of the oils. The major components were α-pinene and β-caryophyllene. Statistical analysis was performed in order to evaluate the variability of the essential oils analyzed. Two groups were formed reflecting only quantitative differences in the content of major compounds. The chemical pattern of essential oils observed for A. flaccida is similar to other Achyrocline species studied, except Achyrocline hyperchlora.     

Temporal expression and steroidal regulation of piRNA pathway genes (mael, piwi, vasa) during Silurana (Xenopus) tropicalis embryogenesis and early larval development

It has been extensively documented that exposure of amphibians and teleost fish to exogenous steroid hormones like estrogen, androgen, xenoestrogen or steroid biosynthesis inhibitors can impair their gonadal development or induce sex reversal against genotypic sex. However, the molecular pathways underlying sexual development and the effects of sex steroids or other exogenous hormones in these aquatic vertebrates remain elusive. Recently, a germ plasm-associated piRNA (piwi-interacting RNA) pathway has been shown to be a determinant in the development of animal gonadal germline cells. In the current study, we examined whether this piRNA pathway is involved in the regulation of sex steroid hormones in gonadal development. We firstly established developmental expression patterns of three key piRNA pathway genes (mael, piwi and vasa), during Silurana (Xenopus) tropicalis embryogenesis and early larval development. All three genes exhibit high expression at early developmental stages and have significantly decreased expression thereafter, indicating a very active involvement of piRNA pathway at the beginning of embryogenesis. We further examined gene expression changes of those genes in frog larvae exposed to two sex steroid biosynthesis inhibitors, fadrozole and finasteride, both of which are known to result in male-biased or female-biased phenotypes, respectively. We found that fadrozole and finasteride exposures increased the expression of piRNA pathway genes such as mael and vasa at the larval stage when the expression of piRNA pathway genes is programmed to be very low. Therefore, our results indicate that the piRNA pathway is likely a common pathway by which different sex steroid hormones regulate gonadal sex differentiation.     

North American Glyptodontines (Xenarthra, Mammalia) in the Upper Pleistocene of northern South America

The Glyptodontidae is one of the most conspicuous groups in the Pleistocene megafauna of the Americas. The Glyptodontinae were involved in the Great American Biotic Interchange (GABI) and their earliest records in North America are about 3.9 Ma, suggesting an earlier formation of the Panamanian landbridge. Taxonomically it is possible to recognize two Pleistocene genera of Glyptodontinae:Glyptodon (ca. 1.8 – 0.008 Ma), restricted to South America, andGlyptotherium (ca. 2.6 – 0.009 Ma), including records in both North and Central America. Here we present the first report of the genusGlyptotherium in South America, from the Late Pleistocene of several fossil localities in Falcón State, northwestern Venezuela. A comparative analysis of the material, represented by cranial and postcranial parts, including the dorsal carapace and caudal rings, suggests a close affinity withGlyptotherium cylindricum (Late Pleistocene of Central Mexico). This occurrence in the latest Pleistocene of the northernmost region of South America Supports the bidirectional faunal migration during the GABI and the repeated re-immigration from North America of South American clades, as has been reported in other members of the Cingulata (e.g., Pampatheriidae).