Avian-like attributes of a virtual brain model of the oviraptorid theropod <Emphasis Type="Italic">Conchoraptor gracilis</Emphasis>

An almost complete adult endoneurocranium of Conchoraptor gracilis Barsbold 1986 (Oviraptoridae; ZPAL MgD-I/95), discovered at the Hermiin Tsav locality (the Upper Cretaceous) in Mongolia, is analyzed. A virtual model of the endoneurocranial cavity was derived from CT scans and represents the most complete maniraptoran endocast to date. It displays reduced olfactory bulbs, large cerebral hemispheres in contact with the expanded cerebellum, an epiphysial projection, optic lobes displaced latero-ventrally, presumptive cerebellar folia, enlarged cerebellar auricles, and a deep medulla oblongata with a prominent ventral flexure. Contrary to Archaeopteryx, the shortened olfactory tract and cerebellum overtopping cerebral hemispheres of Conchoraptor resemble conditions in modern birds. Calculating brain mass relative to body mass indicates that Conchoraptor falls within the range of extant birds, whereas Archaeopteryx occupies a marginal position. Most of the endoneurocranial attributes, however, have a less birdlike appearance in Conchoraptor than do corresponding structures in Archaeopteryx and modern birds in which 1) postero-laterally expanded hemispheral domains broadly overlap the optic lobes, 2) the epiphysis projects to the posterior cerebrum, 3) lateral extension of the optic lobes substantially decreases a brain length-to-width ratio, 4) optic lobe and anterior hindbrain are superposed in lateral view, and 5) cerebellar and midbrain compartments are in distinct superposition. The endoneurocranial characteristics of Conchoraptor, taken together, suggest that the animal had a keen sense of vision, balance, and coordination. The data presented in this study do not allow an unambiguous assessment whether the avian-like endoneurocranial characteristics of the flightless Conchoraptor evolved convergently to those of avian theropods, or indicate a derivation of oviraptorosaurs from volant ancestors.     

An epicuticular multilayer reflector generates the iridescent coloration in chrysidid wasps (Hymenoptera, Chrysididae)

Chrysidid wasps in the subfamily Chrysidinae are brood parasitoids or cleptoparasites of other insects and famous for their cuticular iridescence. In this study, we examine the dorsal abdominal cuticle of the chrysidid wasp Hedychrum rutilans to identify the underlying color mechanism. Using scanning electron microscopy, reflectance spectral analysis, and theoretical calculations, we demonstrate the presence of an epicuticular multilayer reflector consisting of six lamellae with a thickness of 185 nm each. The lamellae exhibit a rough surface probably functioning as spacers between the individual layers. The reflector has a measured reflectance maximum at λ = 630 nm, i.e., in the red part of the visible spectrum of light at normal incidence and the reflectance maximum shifts to green as the angle of incidence increases. Complementary theoretical modeling corroborates the view that the epicuticular multilayer generates the iridescent color of the chrysidid cuticle. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Fetal ear measurements in the prenatal detection of trisomy 21

Although prominent fetal nuchal folds, short long bones, echogenic bowel, and renal pelviectasis have been shown to be associated with trisomy 21, none has acceptable diagnostic efficacy. Diminished fetal ear lengths measured by ultrasound have recently been reported as yet another potential morphological marker for the prenatal detection of trisomy 21. To investigate this further, we measured ear lengths and widths of normal (n = 107) and trisomy 21 (n = 25) second-trimester formalin-preserved fetuses. The normal ear growth characteristics are described and compared with those of trisomy 21 fetuses. The normal fetal ear shape, not unlike that of the neonates, manifested a marked variation. When the ear lengths and widths were regressed against gestational age, the slopes of the regression lines for the two groups were found to be different (P < 0·001). However, despite the statistically significant difference between the ear sizes of normal and trisomy 21 fetuses, the wide range of normal variation seen at each gestational age means that the fetal ear measurements are not diagnostically helpful.     

Living in a “stethoscope”: burrow-acoustics promote auditory specializations in subterranean rodents

Subterranean mammals rely to a great extent on audition for communication and to be alerted to danger. The only hitherto published report on burrow acoustics revealed that in tunnels of blind mole-rats (Spalax ehrenbergi), airborne sounds of 440 Hz propagated best whereas lower and higher frequencies were effectively attenuated. Morpho-functional analyses classify the ear of subterranean mammals as a low-sensitivity and low-frequency device. Concordantly, hearing is characterized by low sensitivity and a restricted frequency range tuned to low frequencies (0.5–4 kHz). Some authors considered the restricted hearing in subterranean mammals vestigial and degenerate due to under-stimulation. In contrast to this view stand a rich (mostly low-frequency) vocal repertoire and progressive structural specializations of the middle and inner ear. Thus, other authors considered these hearing characteristics adaptive. To test the hypothesis that acoustical environment in burrows of different species of subterranean mammals is similar, we measured sound attenuation in burrows of Fukomys mole-rats (formerly known as Cryptomys, cf. Kock et al. 2006) of two differently sized species at different locations in Zambia. We show that in these burrows, low-frequency sounds (200–800 Hz) are not only least attenuated but also their amplitude may be amplified like in a stethoscope (up to two times over 1 m). We suggest that hearing sensitivity has decreased during evolution of subterranean mammals to avoid over-stimulation of the ear in their natural environment. We dedicate this work to Mathias Kawalika, who died in March 2006.     

Atlantic sturgeons (<Emphasis Type="Italic">Acipenser sturio</Emphasis>, <Emphasis Type="Italic">Acipenser oxyrinchus</Emphasis>): American females successful in Europe

Recent molecular data on the maternally inherited mitochondrial (mt) DNA have challenged the traditional view that the now extinct Baltic sturgeon population belonged to the European sturgeon Acipenser sturio. Instead, there is evidence that American sea sturgeon Acipenser oxyrinchus historically immigrated into the Baltic Sea. In this study, we test the hypothesis that A. oxyrinchus introgressed into, rather than replaced, the A. sturio population in the Baltic. We established four single nucleotide polymorphisms (SNPs) in the nuclear MHC II antigen gene with a species-specific SNP pattern. Using an ancient DNA approach and two independent lines of molecular evidence (sequencing of allele-specific clones, SNaPshot), we detected both A. sturio and A. oxyrinchus alleles in the available museum material of the now extinct Baltic sturgeon population. The hybrid nature of the Baltic population was further confirmed by very high levels of heterozygosity. It had been previously postulated that the immigration of the cold-adapted A. oxyrinchus into the Baltic occurred during the Medieval Little Ice Age, when temperature likely dropped below the degree inducing spawning in A. sturio. Under this scenario, our new findings suggest that the genetic mosaic pattern in the Baltic sturgeon population (oxyrinchus mtDNA, sturio and oxyrinchus MHC alleles) is possibly caused by sex-biased introgression where spawning was largely restricted to immigrating American females, while fertilization was predominantly achieved by abundant local European males. The hybrid nature of the former Baltic sturgeon population should be taken into account in the current reintroduction measures. Electronic supplementary material  Supplementary material is available in the online version of this article at and is accessible for authorized users.     

New material of the enigmatic reptile Khurendukhosaurus (Diapsida: Choristodera) from Mongolia

New material of the enigmatic diapsid Khurendukhosaurus is described from the Mongolian type locality, Khuren Dukh, providing additional data on the vertebral column, pelvis, and hind limb. It confirms the choristoderan status of the genus and permits a more detailed phylogenetic analysis that supports a relationship between Khurendukhosaurus and the long-necked Asian Hyphalosauridae. The existence of tall caudal neural spines implies that Khurendukhosaurus was a deep-tailed swimmer. This and the open sacral costocentral sutures suggest a primarily aquatic lifestyle. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Institutional abbreviations  MNHN BL, Museum National d’Histoire Naturelle, Paris, France; MPC, Mongolian Paleontological Center; PIN, Paleontologicheski Institut, Akademii Nauk, Moscow; HMNS, Hayashibara Museum of Natural Sciences, Okayama, Japan.     

<Emphasis Type="BoldItalic">Osedax</Emphasis> borings in fossil marine bird bones

The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We provide the first evidence that Osedax was, and most likely still is, able to consume non-mammalian bones, namely bird bones. Borings resembling those produced by living Osedax were found in bones of early Oligocene marine flightless diving birds (family Plotopteridae). The species that produced these boreholes had a branching filiform root that grew to a length of at least 3 mm, and lived in densities of up to 40 individuals per square centimeter. The inclusion of bird bones into the diet of Osedax has interesting implications for the recent suggestion of a Cretaceous origin of this worm because marine birds have existed continuously since the Cretaceous. Bird bones could have enabled this worm to survive times in the Earth’s history when large marine vertebrates other than fish were rare, specifically after the disappearance of large marine reptiles at the end-Cretaceous mass extinction event and before the rise of whales in the Eocene.     

A new scincomorph lizard from the Palaeocene of Belgium and the origin of Scincoidea in Europe

Well-preserved jaw fragments and skull bones of a new scincomorphan lizard are described from the continental Hainin Formation (Middle Palaeocene) of the Mons Basin in southwestern Belgium. This taxon, Scincoideus haininensis gen. et sp. nov., is characterised by vermiculate dermal rugosities and represents the earliest formally recognised scincoid in Europe. It differs from cordylids (girdled lizards) by lacking the parietal downgrowth and differs from scincids (skinks) by having robustly built bones and a well-developed lingual cusp on tooth crowns. By its mosaic characters, S. haininensis is considered here as being a basal scincoid lizard close to the origin of cordylids and scincids. Palaeobiogeographic analysis suggests that scincoids were present in Europe from the Palaeocene or maybe even before the Cretaceous/Palaeogene boundary and that they were replaced by modern scincoids such as true scincids and cordylids during the Eocene. The origin of the latter two families in Europe was very likely related with the immigration of the first modern mammals.Electronic supplementary material  Supplementary material is available for this article at and accessible for authorised users.     

Bone histology of the titanosaur <Emphasis Type="Italic">Lirainosaurus astibiae</Emphasis> (Dinosauria: Sauropoda) from the Latest Cretaceous of Spain

The titanosaur Lirainosaurus astibiae is the only sauropod species known from the Late Cretaceous of the Iberian Peninsula. Lirainosaurus did not reach a gigantic body size and is one of the smallest sauropods discovered to date. Histological analysis of Lirainosaurus bones, focused on diaphyseal transverse sections of appendicular elements, reveals that Lirainosaurus did not exhibit the osseous microstructure typical for large sauropods, but is comparable with that of the coeval titanosaurs Alamosaurus sanjuanensis, Ampelosaurus atacis, and Magyarosaurus dacus, and also shares histological traits with other small to medium-sized sauropodomorph dinosaurs. Lirainosaurus limb bones exhibit a laminar fibrolamellar bone microstructure interrupted by growth marks, fully obliterated in adulthood by intense secondary remodeling processes which tend to replace completely the primary cortex. Lirainosaurus attained smaller sizes than typical sauropods reducing the rate of primary periosteal osteogenesis and developing an extensive secondary remodeling well before the adult size was reached. Histological organization of Lirainosaurus long bones is more mature than observed in basal neosauropods at similar ontogenetic stage, documenting a case of peramorphosis by pre-displacement. This heterochronic growth would be a reversal of the accelerated pattern of bone deposition typical for the sauropod lineage.     

Decision rules for egg recognition are related to functional roles and chemical cues in the queenless ant Dinoponera quadriceps

The capacity to distinguish colony members from strangers is a key component in social life. In social insects, this extends to the brood and involves discrimination of queen eggs. Chemical substances communicate colony affiliation for both adults and brood; thus, in theory, all colony members should be able to recognize fellow nestmates. In this study, we investigate the ability of Dinoponera quadriceps workers to discriminate nestmate and non-nestmate eggs based on cuticular hydrocarbon composition. We analyzed whether cuticular hydrocarbons present on the eggs provide cues of discrimination. The results show that egg recognition in D. quadriceps is related to both age and the functional role of workers. Brood care workers were able to distinguish nestmate from non-nestmate eggs, while callow and forager workers were unable to do so. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Bacteria on housefly eggs, Musca domestica, suppress fungal growth in chicken manure through nutrient depletion or antifungal metabolites

Female houseflies, Musca domestica (Diptera: Muscidae), lay their eggs in ephemeral resources such as animal manure. Hatching larvae compete for essential nutrients with fungi that also colonize such resources. Both the well-known antagonistic relationship between bacteria and fungi and the consistent presence of the bacterium Klebsiella oxytoca on housefly eggs led us to hypothesize (1) that K. oxytoca, and possibly other bacteria on housefly eggs, help curtail the growth of fungal resource competitors and (2) that such fungi indeed adversely affect the development of housefly larvae. Bacteria washed from housefly eggs significantly reduced the growth of fungi in chicken manure. Nineteen bacterial strains and ten fungal strains were isolated from housefly eggs or chicken manure, respectively. Co-culturing each of all the possible bacterium–fungus pairs revealed that the bacteria as a group, but no single bacterium, significantly suppressed the growth of all fungal strains tested. The bacteria's adverse effect on fungi is due to resource nutrient depletion and/or the release of antifungal chemicals. Well-established fungi in resources significantly reduced the number of larval offspring that completed development to adult flies. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Virtual cranial endocast of the oldest giant panda (<Emphasis Type="Italic">Ailuropoda microta</Emphasis>) reveals great similarity to that of its extant relative

Recent development of computed tomography and three-dimensional visualization techniques has enabled the non-destructive inspection of the endocast morphology of fossil neurocranium, the basic material for paleoneurological study. A virtual cranial endocast was reconstructed based on the first skull of the oldest giant panda, Ailuropoda microta, discovered recently and dated at more than 2 Myr (million years) ago. It was compared with that of the extant giant panda (A. melanoleuca) and that of the polar bear (Ursus maritimus), as well as CT slices of the late Pleistocene A. baconi. The overall endocast morphology of A. microta is more similar to that of A. baconi and A. melanoleuca than to that of U. maritimus. The absolute endocast size is the smallest in A. microta, largest in A. baconi, and intermediate in A. melanoleuca. However, the proportion of cerebral volume to total endocast size is very close to each other between the oldest and extant giant panda, as well as the sulcal length per unit area of cerebral endocast surface. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

浑河底泥反硝化厌氧甲烷氧化菌群落多样性的时空分布特征及其与环境因子关系分析

为了解浑河底泥中反硝化厌氧甲烷氧化菌——Candidatus Methylomirabilis oxyfera(M.oxyfera)群落多样性的时空分布特征,通过克隆文库技术考察M.oxyfera的16S rRNA和pmo A功能基因的多样性时空分布特征,并结合多元直接梯度分析来研究环境因子(水样和底泥的理化性质)与其之间的关系.9月浑河上、中、下游底泥样品中M.oxyfera的16S rRNA基因的OTU数在2~5之间,Shannon-Wiener多样性指数变化范围为0.21~1.4,呈现出中游上游下游的分布特征.pmo A功能基因上游的OTU数和Shannon-Wiener多样性指数明显高于中游和下游,上游的Shannon-Wiener多样性指数分别是中游和下游的3.5倍和2.3倍,因此M.oxyfera的群落多样性呈现出明显的地域性分布特征.3号采样点处3月采集样品中M.oxyfera的16S rRNA和pmo A的OTU数目分别是6和5,明显高于9月对应的OTU数目,Shannon-Wiener指数也明显比9月高(1.40.68;1.570.00),因此M.oxyfera的群落多样性呈现出明显的季节分布特征.多元直接梯度分析结果表明底泥中DOC浓度、底泥电导率、水体中TOC含量和水体中亚硝酸氮浓度是影响M.oxyfera群落多样性的主要环境因子.     

Early and severe tricuspid valve dysplasia in a fetus with cardiospondylocarpofacial syndrome due to a variant c.616T>G p.(Tyr206Asp) in MAP3K7

Cardiospondylocarpofacial syndrome (CSCF; MIM#157800) is a rare condition caused by monoallelic variants in the MAP3K7 gene. The characteristic features of CSCF include growth retardation, facial dysmorphism, carpal-tarsal fusion, dorsal spine synostosis, deafness, inner ear malformation, cardiac septal defect and valve dysplasia. We present here a 20-week-old fetus with cardiospondylocarpofacial syndrome arising from a de novo variant c.616T>G p.(Tyr206Asp) in the MAP3K7 (NM_145331.3) gene with early and severe tricuspid valve dysplasia as a prenatal manifestation. Fetal echocardiography revealed tricuspid regurgitation with valve prolapse. Fetus had facial dysmorphism and dilated right atrium and right ventricle with tricuspid valve dysplasia on perinatal evaluation. To the best of our knowledge, this is the first report mentioning the prenatal manifestation of cardiospondylocarpofacial syndrome.     

Bee-hawking by the wasp, <Emphasis Type="BoldItalic">Vespa velutina</Emphasis>, on the honeybees <Emphasis Type="BoldItalic">Apis cerana</Emphasis> and <Emphasis Type="BoldItalic">A</Emphasis>. <Emphasis Type="BoldItalic">mellifera</Emphasis>

The vespine wasps, Vespa velutina, specialise in hawking honeybee foragers returning to their nests. We studied their behaviour in China using native Apis cerana and introduced A. mellifera colonies. When the wasps are hawking, A. cerana recruits threefold more guard bees to stave off predation than A. mellifera. The former also utilises wing shimmering as a visual pattern disruption mechanism, which is not shown by A. mellifera. A. cerana foragers halve the time of normal flight needed to dart into the nest entrance, while A. mellifera actually slows down in sashaying flight manoeuvres. V. velutina preferentially hawks A. mellifera foragers when both A. mellifera and A. cerana occur in the same apiary. The pace of wasp-hawking was highest in mid-summer but the frequency of hawking wasps was three times higher at A. mellifera colonies than at the A. cerana colonies. The wasps were taking A. mellifera foragers at a frequency eightfold greater than A. cerana foragers. The final hawking success rates of the wasps were about three times higher for A. mellifera foragers than for A. cerana. The relative success of native A. cerana over European A. mellifera in thwarting predation by the wasp V. velutina is interpreted as the result of co-evolution between the Asian wasp and honeybee, respectively.     

镉铅复合胁迫下根表铁锰氧化胶膜厚度对美洲商陆富集镉的影响

为了探讨根表铁锰氧化胶膜厚度及共存离子铅(Pb)对美洲商陆富集镉(Cd)影响,采用水培的方法,诱导培育了胶膜厚度具有极显著差异的美洲商陆(低膜美洲商陆、中膜美洲商陆和高膜美洲商陆),分别进行低Cd低Pb、低Cd高Pb、高Cd低Pb、高Cd高Pb等4种不同金属组合的胁迫处理,观察美洲商陆生长状况、测定植株对Cd的富集量、抗胁迫生理活性物质的表达量.结果表明:中膜和高膜美洲商陆侧根发达,新生根较多,高Cd胁迫对根系发育有较强的抑制作用.高Cd条件下,植株对Cd的富集量为高膜美洲商陆中膜美洲商陆低膜美洲商陆,高膜美洲商陆Cd总富集量可达89765.69 mg·kg-1(以干重计).低Cd条件下,植株对Cd的富集量为低膜美洲商陆高膜美洲商陆中膜美洲商陆.高Pb处理,可提高低膜和高膜美洲商陆Cd富集量,但显著降低中膜美洲商陆Cd富集量.根系分泌的可溶性还原糖含量、叶及根部合成的可溶性蛋白含量与根表铁锰氧化胶膜的厚度成正相关.中膜和高膜美洲商陆叶片及根部可溶性蛋白含量还受到不同金属组合胁迫的影响.镉铅复合胁迫使美洲商陆叶片及根部可溶性蛋白含量极显著高于对照组.     

Metabolism and water loss are not related to environmental heterogeneity in two mygalomorph spiders

Laboratory water flumes are artificial troughs of moving water widely used in hydraulic studies of fluvial systems to investigate real-world problems at smaller, more manageable scales. Water flumes have also been used to understand bone transportation sorting and bone orientation found in the fossil record using actual bones. To date, these studies have not involved scaled bones. A 1/12 scale model of a 21.8-m long skeleton of Apatosaurus, a long-necked sauropod dinosaur from the Late Jurassic, was used to explore three problems at Dinosaur National Monument (USA) that cannot be explained by tradition bone flume studies: (1) why there is an abrupt bend in articulated vertebrae, (2) why articulated dorsals are inverted relative to the pelvis, and (3) how bone jams form. The flume experiments established that (1) bed friction with the wing-like transverse processes of vertebrae resists the force of the water flow, whereas those vertebrae lacking the processes are free to pivot in the flow; (2) elevation of the dorsal vertebrae by the transverse processes subjects the vertebrae to the energy of the flow stream, which causes the vertebrae to flip. Computation fluid dynamics (CFD) software shows this flip was due to differential pressure on the upstream and downstream sides. (3) The formation and growth of bone clusters or jams (analogous to log jams in rivers) occur as transported bones pile against an initial obstruction and jammed bones themselves become obstacles. These preliminary studies show that scale models can provide valuable insights into certain taphonomic problems that cannot be obtained by traditional bone flume studies.

     

A new neosuchian with Asian affinities from the Jurassic of northeastern Brazil

Phylogenetic relationships near the origin of extant crocodylians are weakly supported, and this lack of resolution makes for poor estimates of taxonomic and morphological diversity. Previously known taxa are found throughout the Cretaceous in Laurasia and at a few sites from Brazil, Australia, and northern Africa. Here, we report Batrachomimus pastosbonensis gen. et sp. nov. from the Late Jurassic of northeastern Brazil, which is deeply nested within Neosuchia and associated to the Cretaceous Asian paralligatorids. The new taxon predates all other members of Paralligatoridae and its immediate sister group (including Eusuchia) by 30 million years. A nearly complete skull, osteoderms, and limb bones were recovered, and autapomorphies of B. pastosbonensis include a scalloped lateral margin of the rostrum in dorsal view, unsculpted alveolar margin at the caudalmost portion of the maxilla, blunt lateral prongs on the jugal at the base of the postorbital bar, hourglass shaped choanae, and pterygoid choanal septum extended between the palatal shelves of the palatines. The crocodyloid-like skull proportions and the slender, conical teeth suggest an amphibious and piscivorous life history to this 1 m long animal.

     

Anatomical and physiological divergences and compensatory effects in two Leymus chinensis (Poaceae) ecotypes in Northeast China

The purpose of this study was to investigate the anatomical and physiological differences between two Leymus chinensis ecotypes coexisted in semi-humid meadow and semi-arid steppe. The study addressed the hypothesis that, at same habitat, the two ecotypes exhibit remarkable divergences in adaptive strategies under drought and salinity, and the function of these strategies is compensatory. Leaf samples were collected from each type at the two sites in field. Sections of 2 cm × 2 cm were cut from the middle of fully expanded leaves and fixed in FAA. Leaf anatomical traits (e.g. stomatal density, leaf thickness and vessel diameters) were examined, and leaf mass per area (LMA), relative water content (RWC), proline, K⁺ and Na⁺ were measured. Compared with the gray green type (GG), the yellow green type (YG) with relative greater LMA and leaf thickness, lower stomatal density and index exhibited more obvious xerophil-liked anatomical traits, while higher RWC, proline, K⁺ and K⁺/Na⁺ for the GG type suggested that the ability of osmotic adjustment and salt tolerance of the GG type were stronger than the YG type. Stronger xerophytic anatomical traits were the supplementary strategies of the YG type for its low ability of osmotic adjustment and salt tolerance to drought and salinity.Concluding, there exist significant differences in anatomical and physiological strategies between the two ecotypes and the compensatory effects of these strategies enable the two ecotypes coexist at similar habitat.     

Taxonomy of oxalotrophic <Emphasis Type="Italic">Methylobacterium</Emphasis> strains

Most of the oxalotrophic bacteria are facultative methylotrophs and play important ecological roles in soil fertility and cycling of elements. This study gives a detailed picture of the taxonomy and diversity of these bacteria and provides new information about the taxonomical variability within the genus Methylobacterium. Twelve mesophilic, pink-pigmented, and facultatively methylotrophic oxalate-oxidizing strains were included in this work that had been previously isolated from the soil and some plant tissues by the potassium oxalate enrichment method. The isolates were characterized using biochemical tests, cellular lipid profiles, spectral characteristics of carotenoid pigments, G+C content of the DNA, and 16S rDNA sequencing. The taxonomic similarities among the strains were analyzed using the simple matching (S _SM) and Jaccard (S _J) coefficients, and the UPGMA clustering algorithm. The phylogenetic position of the strains was inferred by the neighbor-joining method on the basis of the 16S rDNA sequences. All isolates were Gram-negative, facultatively methylotrophic, oxidase and catalase positive, and required no growth factors. Based on the results of numerical taxonomy, the strains formed four closely related clusters sharing ≥85% similarity. Analysis of the 16S rDNA sequences demonstrated that oxalotrophic, pink-pigmented, and facultatively methylotrophic strains could be identified as members of the genus Methylobacterium. Except for M. variabile and M. aquaticum, all of the Methylobacterium type strains tested had the ability of oxalate utilization. Our results indicate that the capability of oxalate utilization seems to be an uncommon trait and could be used as a valuable taxonomic criterion for differentiation of Methylobacterium species.