Recruitment and Other Communication Behavior in the Ponerine Ant Ectatomma ruidum

The ponerine ant Ectatomma ruidum, though previously reported to possess only rudimentary recruitment ability, was found to lay chemical trails for mass recruitment to rich or difficult food sources. The pheromone originates from the Dufour's gland, a new source of trail pheromones in the primitive ant subfamily Ponerinae. During nest emigrations, E. ruidum practices stereotyped social carrying in the myrmicine mode. The discovery of this form of social carrying and of a recruitment pheromone in the Dufour's gland secretions support the hypothesis that the subfamily Myrmicinae is derived from an ectatommine ancestor. Other communication behaviors exhibited by E. ruidum include exchange of liquid food carried between the mandibles, chemical alarm communication, nest entrance marking, and an additional social carrying posture previously unknown in ants.     

Interspecific variation in the defence secretions of Nasutitermes soldiers

Termite soldiers of the genus Nasutitermes (Isoptera, Termitidae, Nasutitermitinae) eject a viscous, sticky defense secretion composed of non-polar monoterpene hydrocarbons and polyoxygenated diterpenes from the frontal gland. Chemical compositions are described in detail for the East African species, N. kempae and N. infuscatus, and for the Neotropical species N. ephratae. Additional comparisons with the new world species N. costalis, N. rippertii and N. octopilis are presented. The structure of a new monohydroxykempene from N. ephratae is described, and a physicochemical model for the stickiness of the glue is presented. Although the structures of the individual secretion components vary within the genus, the glue-like nature of the secretion remains essentially unchanged. Chemical analysis of soldier defense secretions may be useful in studying the systematic biology of termites.     

The evolution of the lepidosaurian lower temporal bar: new perspectives from the Late Cretaceous of South China

Until recently, it was considered axiomatic that the skull of lizards and snakes arose from that of a diapsid ancestor by loss of the lower temporal bar. The presence of the bar in the living New Zealand Tuatara, Sphenodon, was thus considered primitive, corroborating its status as a ‘living fossil’. A combination of new fossils and rigorous phylogeny has demonstrated unequivocally that the absence of the bar is the primitive lepidosaurian condition, prompting questions as to its function. Here we describe new material of Tianyusaurus, a remarkable lizard from the Late Cretaceous of China that is paradoxical in having a complete lower temporal bar and a fixed quadrate. New material from Jiangxi Province is more complete and less distorted than the original holotype. Tianyusaurus is shown to be a member of the Boreoteiioidea, a successful clade of large herbivorous lizards that were dispersed through eastern Asia, Europe and North America in the Late Cretaceous, but disappeared in the end-Cretaceous extinction. A unique combination of characters suggests that Tianyusaurus took food items requiring a large gape.     

The syndermatan phylogeny and the evolution of acanthocephalan endoparasitism as inferred from 18S rDNA sequences

The phylogeny of the Syndermata (Rotifera: Monogononta, Bdelloidea, Seisonidea; Acanthocephala: Palaeacanthocephala, Eoacanthocephala, Archiacanthocephala) is key to understanding the evolution of acanthocephalan endoparasitism from free-living ancestors. In the present study, maximum likelihood, distance/neighbor-joining, and maximum parsimony analyses have been carried out based on 18S rDNA data of 22 species (four new sequences). The results suggest a monophyletic origin of the Eurotatoria (Monogononta+Bdelloidea). Seison appears as the acanthocephalan sistergroup. Palaeacanthocephala split into an "Echinorhynchus"-and a "Leptorhynchoides"-group, the latter sharing a monophyletic origin with the Eoacanthocephala and Archiacanthocephala. As inferred from the phylogeny obtained acanthocephalan endoparasitism evolved from a common ancestor of Seison and Acanthocephala that lived epizoically on an early mandibulate. Probably, an acanthocephalan stem species invaded the mandibulate host, thus establishing an endoparasitic lifestyle. Subsequently, vertebrates (or gnathostomes) became part of the parasite's life cycle. In the stem line of the Archiacanthocephala, a terrestrial life cycle has evolved, with an ancestor of the Tracheata (Insecta, Myriapoda) acting as intermediate host.     

Cladistical analysis of primitive G-band sequences for the karyotype of the ancestor of the Cricetidae complex of rodents

Homologous segments identified by G-banding sequences of chromosomes of Peromyscus boylii, Neotoma micropus, Oryzomys capito, (Family Cricetidae) Rattus norvegicus, Melomys burtoni, and Apodemus sylvaticus (Family Muridae) were used to hypothesize a chromosomal condition for the cricetid ancestor. A critical assumption in proposing the primitive G-banding sequences for a given chromosome is that if the outgroup and ingroup taxa have a specific sequence, then the ancestor of the ingroup taxa also had that same sequence. Using this methodology, (chromosome numbers refer to proposed homology to the standardized karyotype for Peromyscus), we propose that: (1) the primitive banding pattern of chromosome 1 was identical to that of Neotoma; (2) the primitive patterns of chromosomes 2, 3, 4, 6, 7, 8, 9, 10, 11, and 12 were primitive banding patterns of 5 and 13 were undetermined; (4) a major portion of the banding patterns of 14 and X were present in the ancestral karyotype. Only the largest 14 autosomes and X were examined because the smaller elements had insufficient G-band definition to ensure reasonable accuracy. The karyotype ancestral to that of Peromyscus, Neotoma, and Oryzomys may be as above and the banding patterns of 5, 13, and 14 were acrocentric and identical to those shown for Peromyscus, Neotoma, and Oryzomys (Fig. 1). In the primitive karyotype, heterochromatin (C-band material) was probably limited to the centromeric regions. If the primitive karyotype is as described above, then it is possible to determine the direction, type, and magnitude of chromosomal evolution evident in the various cricetid lineages. Based on the available data, radiation from the ancestral cytotype is characterized by a nonrandom distribution of types of chromosomal changes. Within many genera, more rearrangements occur in the 14 largest autosomal chromosomes of some congeneric species than distinguish the proposed primitive conditions for the genera Peromyscus, Neotoma, and Oryzomys. It would appear that the extensive morphological radiation from the primitive cricetid ancestor as indicated by the presence of over 100 surviving genera within the family, was not accompanied by extensive karyotypic changes. The magnitude of chromosomal variation that accompanies speciation in these genera appears to range from no detectable chromosomal evolution to a radical reorganization of the genome.     

Facilitated by nature and agriculture: performance of a specialist herbivore improves with host-plant life history evolution, domestication, and breeding

Plant defenses against herbivores are predicted to change as plant lineages diversify, and with domestication and subsequent selection and breeding in the case of crop plants. We addressed whether defense against a specialist herbivore declined coincidently with life history evolution, domestication, and breeding within the grass genus Zea (Poaceae). For this, we assessed performance of corn leafhopper (Dalbulus maidis) following colonization of one of four Zea species containing three successive transitions: the evolutionary transition from perennial to annual life cycle, the agricultural transition from wild annual grass to primitive crop cultivar, and the agronomic transition from primitive to modern crop cultivar. Performance of corn leafhopper was measured through seven variables relevant to development speed, survivorship, fecundity, and body size. The plants included in our study were perennial teosinte (Zea diploperennis), Balsas teosinte (Zea mays parviglumis), a landrace maize (Zea mays mays), and a hybrid maize. Perennial teosinte is a perennial, iteroparous species, and is basal in Zea; Balsas teosinte is an annual species, and the progenitor of maize; the landrace maize is a primitive, genetically diverse cultivar, and is ancestral to the hybrid maize; and, the hybrid maize is a highly inbred, modern cultivar. Performance of corn leafhopper was poorest on perennial teosinte, intermediate on Balsas teosinte and landrace maize, and best on hybrid maize, consistent with our expectation of declining defense from perennial teosinte to hybrid maize. Overall, our results indicated that corn leafhopper performance increased most with the agronomic transition, followed by the life history transition, and least with the domestication transition.     

Ostéologie de Clupavus maroccanus(Crétacé supérieur du Maroc) et considérations sur la position systématique et les relations des Clupavidae au sein de l'ordre des Clupéiformes sensu stricto (Pisces,Teleostei)

Osteology proves definitively that Clupavusmaroccanus is a typical Cluepoid (lateroparietal skull, ethmoidean and fronto-occipital fontanels, recessus lateralis, latero-sagittal fronto-parietal crest, clupeid ural complex, etc…). Clupavus represents a particular non-serrated family, the Clupavidae, different from the Dussumieriidae and the Congothrissidae, the two other primitive non-serrated Clupeoid families. Nor is Clupavus the ancestor of these two families. The systematic position and the relationships of the Clupavidae within the order Clupeiformes sensu stricto are discussed.     

Morphology and Histochemistry of the Aesthetasc-Associated Epidermal Glands in Terrestrial Hermit Crabs of the Genus Coenobita (Decapoda: Paguroidea)

Crustaceans have successfully adapted to a variety of environments including fresh- and saltwater as well as land. Transition from an aquatic to a terrestrial lifestyle required adaptations of the sensory equipment of an animal, particularly in olfaction, where the stimulus itself changes from hydrophilic to mainly hydrophobic, air-borne molecules. Hermit crabs Coenobita spp. (Anomura, Coenobitidae) have adapted to a fully terrestrial lifestyle as adults and have been shown to rely on olfaction in order to detect distant food items. We observed that the specialized olfactory sensilla in Coenobita, named aesthetascs, are immersed in a layer of mucous-like substance. We hypothesized that the mucous is produced by antennal glands and affects functioning of the aesthetascs.Using various microscopic and histochemical techniques we proved that the mucous is produced by aesthetasc-associated epidermal glands, which we consider to be modified rosette-type aesthetasc tegumental glands known from aquatic decapods. These epidermal glands in Coenobita are multicellular exocrine organs of the recto-canal type with tubulo-acinar arrangement of the secretory cells. Two distinct populations of secretory cells were clearly distinguishable with light and electron microscopy. At least part of the secretory cells contains specific enzymes, CUB-serine proteases, which are likely to be secreted on the surface of the aesthetasc pad and take part in antimicrobial defense. Proteomic analysis of the glandular tissue corroborates the idea that the secretions of the aesthetasc-associated epidermal glands are involved in immune responses.We propose that the mucous covering the aesthetascs in Coenobita takes part in antimicrobial defense and at the same time provides the moisture essential for odor perception in terrestrial hermit crabs. We conclude that the morphological modifications of the aesthetasc-associated epidermal glands as well as the functional characteristics of their secretions are important adaptations to a terrestrial lifestyle.     

A morphometric mapping analysis of lower fourth deciduous premolar in hominoids: Implications for phylogenetic relationship between Nakalipithecus and Ouranopithecus

Clarifying morphological variation among African and Eurasian hominoids during the Miocene is of particular importance for inferring the evolutionary history of humans and great apes. Among Miocene hominoids, Nakalipithecus and Ouranopithecus play an important role because of their similar dates on different continents. Here, we quantify the lower fourth deciduous premolar (dp4) inner morphology of extant and extinct hominoids using a method of morphometric mapping and examine the phylogenetic relationships between these two fossil taxa. Our data indicate that early Late Miocene apes represent a primitive state in general, whereas modern great apes and humans represent derived states. While Nakalipithecus and Ouranopithecus show similarity in dp4 morphology to a certain degree, the dp4 of Nakalipithecus retains primitive features and that of Ouranopithecus exhibits derived features. Phenotypic continuity among African ape fossils from Miocene to Plio-Pleistocene would support the African origin of African apes and humans (AAH). The results also suggest that Nakalipithecus could have belonged to a lineage from which the lineage of Ouranopithecus and the common ancestor of AAH subsequently derived.     

On the anatomy and relationships ofEfraasia diagnostica (Huene) n. gen., a prosauropod dinosaur (Reptilia: Saurischia) from the Upper Triassic of Germany

Palaeosaurus (?) diagnosticus Huene from the Stubensandstone (Upper Triassic, Norian) of Nordwürttemberg, Germany is made the type species of a new genus of prosauropod dinosaurEfraasia, which is referred to the family Anchisauridae. The anatomy ofEfraasia diagnostica is conservative and it was an ideal ancestor for the later and more specializedAnchisaurus polyzelus of North America. The slenderness of the manus and pes ofEfraasia andAnchisaurus is matched amongst prosauropods only by the feet ofGyposaurus capensis andThecodontosaurus antiquus. Staurikosaurus pricei Colbert from the Upper Triassic of Brazil is probably a very primitive theropod dinosaur.     

Odoriferous Defensive Stink Gland Transcriptome to Identify Novel Genes Necessary for Quinone Synthesis in the Red Flour Beetle,Tribolium castaneum

Chemical defense is one of the most important traits, which endow insects the ability to conquer a most diverse set of ecological environments. Chemical secretions are used for defense against anything from vertebrate or invertebrate predators to prokaryotic or eukaryotic parasites or food competitors. Tenebrionid beetles are especially prolific in this category, producing several varieties of substituted benzoquinone compounds. In order to get a better understanding of the genetic and molecular basis of defensive secretions, we performed RNA sequencing in a newly emerging insect model, the red flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae). To detect genes that are highly and specifically expressed in the odoriferous gland tissues that secret defensive chemical compounds, we compared them to a control tissue, the anterior abdomen. 511 genes were identified in different subtraction groups. Of these, 77 genes were functionally analyzed by RNA interference (RNAi) to recognize induced gland alterations morphologically or changes in gland volatiles by gas chromatography-mass spectrometry. 29 genes (38%) presented strong visible phenotypes, while 67 genes (87%) showed alterations of at least one gland content. Three of these genes showing quinone-less (ql) phenotypes – Tcas-ql VTGl; Tcas-ql ARSB; Tcas-ql MRP – were isolated, molecularly characterized, their expression identified in both types of the secretory glandular cells, and their function determined by quantification of all main components after RNAi. In addition, microbe inhibition assays revealed that a quinone-free status is unable to impede bacterial or fungal growth. Phylogenetic analyses of these three genes indicate that they have evolved independently and specifically for chemical defense in beetles.     

Grasshopper oral secretions increase salicylic acid and abscisic acid levels in wounded leaves of Arabidopsis thaliana

Recent investigations showed that the model plant Arabidopsis thaliana specifically responds to herbivory-associated molecular patterns by activating a sophisticated signaling network. The lipase activity of insect oral secretions was shown to elevate oxylipin levels when applied to puncture wounds in leaves. The results also demonstrated that the oral secretions of the generalist Schistocerca gregaria contained other, probably non-proteinous, elicitors of plant defense responses which induced mitogen-activated protein kinases, calcium signaling and ethylene levels.¹ This addendum presents data on the levels of additional phytohormones that are elevated after application of S. gregaria oral secretion to wounded leaves. Abscisic acid and salicylic acid levels are significantly elevated after elicitation with S. gregaria oral secretions, adding another layer of complexity to the herbivory-induced response of A. thaliana.Key words: abscisic acid, Arabidopsis, herbivory, salicylic acid, Schistocerca gregaria     

The evolution of hemolytic saponin content in wild and cultivated Alfalfa (Medicago sativa,Fabaceae)

Hemolytic saponin content was determined of the leaves of 1213 plants of different variants ofMedicago sativa s.l. (including wild and cultivated alfalfa), and a close ally,M. papillosa. The latter species had a much higher content than any of the groups ofM. sativa. Medicago sativa ssp. caerulea, the most important ancestor of alfalfa, had a very low content of hemolytic saponins. The most primitive forms of cultivated alfalfa examined, from Turkey, and wildM. sativa ssp. sativa of Turkey, also both had very low contents of hemolytic saponins. This is consistent with, and likely explained by, a direct origin of the two Turkish groups from sympatricM. sativa ssp.caerulea. The second most important ancestor of alfalfa,M. sativa ssp.falcata, had the highest content of any of the examined groups ofM. sativa. Modern “Western” (European, NorthAmerican) cultivars and Western ruderal populations had intermediate levels of hemolytic saponins. This is consistent with, and likely explained by, their origin by hybridization and introgression between the low saponin groups noted above andM. sativa ssp.falcata.     

Photosynthetic Bradyrhizobia Are Natural Endophytes of the African Wild Rice Oryza breviligulata

We investigated the presence of endophytic rhizobia within the roots of the wetland wild rice Oryza breviligulata, which is the ancestor of the African cultivated rice Oryza glaberrima. This primitive rice species grows in the same wetland sites as Aeschynomene sensitiva, an aquatic stem-nodulated legume associated with photosynthetic strains of Bradyrhizobium. Twenty endophytic and aquatic isolates were obtained at three different sites in West Africa (Senegal and Guinea) from nodal roots of O. breviligulata and surrounding water by using A. sensitiva as a trap legume. Most endophytic and aquatic isolates were photosynthetic and belonged to the same phylogenetic Bradyrhizobium/Blastobacter subgroup as the typical photosynthetic Bradyrhizobium strains previously isolated from Aeschynomene stem nodules. Nitrogen-fixing activity, measured by acetylene reduction, was detected in rice plants inoculated with endophytic isolates. A 20% increase in the shoot growth and grain yield of O. breviligulata grown in a greenhouse was also observed upon inoculation with one endophytic strain and one Aeschynomene photosynthetic strain. The photosynthetic Bradyrhizobium sp. strain ORS278 extensively colonized the root surface, followed by intercellular, and rarely intracellular, bacterial invasion of the rice roots, which was determined with a lacZ-tagged mutant of ORS278. The discovery that photosynthetic Bradyrhizobium strains, which are usually known to induce nitrogen-fixing nodules on stems of the legume Aeschynomene, are also natural true endophytes of the primitive rice O. breviligulata could significantly enhance cultivated rice production.     

The prolacertid LepidosaurianCosesaurus avicepsEllenberger & Villalta, a claimed «Protoavian from the Middle Triassic of Spain

Cosesaurus aviceps, a small, probable diapsid reptile from the Ladinian (Middle Triassic) of Montral-Alcover (prov. Tarragona, Spain), has been reported as an ancestor of the Neornites. The only known specimen of this taxon is likely an inmature individual. The allometric growth models have been introduced in the character analysis, to infer the features of the adult Cosesaurus. For the present analysis, only the features that can be ascertained without doubt have been retained. The characters have been classified as primitive and derived. Cosesaurus shares all the ten derived characters we have found with Prolacertiformes, especially with Macrocnemus. The sister-group Macrocnemus + Cosesaurus is characterized by the relatively elongated neck in respect both to the skull and trunk length, 7–8 cervical vertebrae with the centra relatively elongated, and a relatively narrow distal femur region.     

Two new species of canaliculate rudists (Dictyoptychidae) from southeastern turkey

Two new species of canaliculate rudist genus Dictyoptychus Douvillé: Dictyoptychus quadrizonalis n. sp. and Dictyoptychus vanensis n. sp., are described from the Maastrichtian limestone block of the ophiolitic unit of the Geva?-Van area, southeastern Turkey. The new species are mainly characterized by the complex structure of the canal layer of the lower valve, and also they seem to be most primitive species of Dictyoptychus and transitional between Dictyoptychus Douvillé and its presumed ancestor, Eodictyoptychus Skelton and El-Asa'ad. Many specimens of the Dictyoptychus paronai (Kühn), allows us to first determination of the upper valve shape and to study also of the lower valve canal layer.     

Root Secretion of Defense-related Proteins Is Development-dependent and Correlated with Flowering Time

Proteins found in the root exudates are thought to play a role in the interactions between plants and soil organisms. To gain a better understanding of protein secretion by roots, we conducted a systematic proteomic analysis of the root exudates of Arabidopsis thaliana at different plant developmental stages. In total, we identified 111 proteins secreted by roots, the majority of which were exuded constitutively during all stages of development. However, defense-related proteins such as chitinases, glucanases, myrosinases, and others showed enhanced secretion during flowering. Defense-impaired mutants npr1-1 and NahG showed lower levels of secretion of defense proteins at flowering compared with the wild type. The flowering-defective mutants fca-1, stm-4, and co-1 showed almost undetectable levels of defense proteins in their root exudates at similar time points. In contrast, root secretions of defense-enhanced cpr5-2 mutants showed higher levels of defense proteins. The proteomics data were positively correlated with enzymatic activity assays for defense proteins and with in silico gene expression analysis of genes specifically expressed in roots of Arabidopsis. In conclusion, our results show a clear correlation between defense-related proteins secreted by roots and flowering time.     

Hybridization between the African clawed frogs Xenopus laevis and Xenopus muelleri (Pipidae) increases the multiplicity of antimicrobial peptides in skin secretions of female offspring

Peptidomic analysis was used to compare the distribution of host-defense peptides in norepinephrine-stimulated skin secretions from laboratory-generated female F1 hybrids of the common clawed frog Xenopus laevis (Daudin, 1802) and Mueller's clawed frog Xenopus muelleri (Peters, 1844) with the corresponding distribution in skin secretions from the parent species. A total of 18 peptides were identified in secretions from the hybrid frogs. Eleven peptides (magainin-1, magainin-2, CPF-1, CPF-3, CPF-4, CPF-5, CPF-6, CPF-7, XPF-1, XPF-2, and PGLa) were identified in secretions of both the hybrids and X. laevis. Four peptides (magainin-M1, XPF-M1, CPF-M1, and tigerinin-M1) were previously found in skin secretions of X. muelleri but magainin-M2 and CPF-M2 from X. muelleri were not detected. Three previously undescribed peptides (magainin-LM1, PGLa-LM1, and CPF-LM1) were purified from the secretions of the hybrid frogs that were not detected in secretions from either X. laevis or X. muelleri. Magainin-LM1 differs from magainin-2 from X. laevis by a single amino acid substitution (Gly¹³ → Ala) but PGLa-LM1 and CPF-LM1 differ appreciably in structure from orthologs in the parent species. CPF-LM1 shows potent, broad-spectrum antimicrobial activity and is hemolytic. The data indicate that hybridization increases the multiplicity of skin host-defense peptides in skin secretions. As the female F1 hybrids are fertile, hybridization may represent an adaptive strategy among Xenopus species to increase protection against pathogenic microorganisms in the environment.     

The development and evolution of insect mouthparts as revealed by the expression patterns of gnathocephalic genes

To understand better both the development and evolution of insect mouthparts, we have compared the expression pattern of several developmentally important genes in insects with either mandibulate or stylate-haustellate mouthparts. Specifically, we examined the expression of the proboscipedia (pb) and Distal-less (Dll) gene products as well as three regulators of pb, Sex combs reduced (Scr), Deformed (Dfd), and cap 'n' collar (cnc). These genes are known to control the identity of cells in the gnathal segments of Drosophila melanogaster and would appear to have similar conserved functions in other insects. Together we have made an atlas of gene expression in the heads of three insects: Thermobia domestica and Acheta domestica, which likely exemplify the mandibulate mouthparts present in the common insect ancestor, and Oncopeltus fasciatus, which has piercing-sucking mouth parts that are typical of the Hemiptera. At the earliest stages of embryogenesis, only the expression of pb was found to differ dramatically between Oncopeltus and the other insects examined, although significant differences were observed later in development. This difference in pb expression reflects an apparent divergence in the specification of gnathal identity between mandibulate and stylate-haustellate mouthparts, which may result from a "phylogenetic homeosis" that occurred during the evolution of the Hemiptera.