Morphological convergence in Hippidion and Equus (Amerhippus) South American equids elucidated by ancient DNA analysis

Unusual equids named hippidions inhabited South America for more than 2 MY (million years). Like many other animals they succumbed to the worldwide climatic change that occurred 10 KY (thousand years) ago and completely disappeared during the great late Pleistocene megafaunal extinction. According to fossil records and numerous dental, cranial, and postcranial characters, Hippidion and Equus lineages are known to have diverged prior to 10 MY. Some equid bones from Rio Verde and Ultima Esperanza (Patagonia, Chile) dating back to the late Pleistocene period (8-13 KY) have been identified as Hippidion saldiasi, while a few teeth have been assigned to Equus. Six samples of those remains have been obtained from the Zoological Museum of Amsterdam for ancient DNA analysis to try to place Hippidion in the evolutive tree of Perissodactyla. Two samples of Hippidion and one sample of Equus yielded 241-394 bp of the mtDNA control region and 172-296 bp of the cytochrome b gene. Unexpectedly, all the sequences clustered deep inside the Equus genus, casting doubt on the initial identification of the bones. For paleontologists, one of the striking and classical diagnostic characters of Hippidion is their extremely short and massive metapodials, a probable locomotory adaptation to the Andine steep slopes. However, our DNA analysis reveals that a very Hippidion-like metapod might also have been possessed by another South American equid, i.e., Equus (Amerhippus), an interpretation supported by complementary anatomical observations. This adaptive convergence between members of the two South American equid genera may lead paleontologists to limb bone misidentification.     

Evolution, systematics, and phylogeography of pleistocene horses in the new world: a molecular perspective

The rich fossil record of horses has made them a classic example of evolutionary processes. However, while the overall picture of equid evolution is well known, the details are surprisingly poorly understood, especially for the later Pliocene and Pleistocene, c. 3 million to 0.01 million years (Ma) ago, and nowhere more so than in the Americas. There is no consensus on the number of equid species or even the number of lineages that existed in these continents. Likewise, the origin of the endemic South American genus Hippidion is unresolved, as is the phylogenetic position of the "stilt-legged" horses of North America. Using ancient DNA sequences, we show that, in contrast to current models based on morphology and a recent genetic study, Hippidion was phylogenetically close to the caballine (true) horses, with origins considerably more recent than the currently accepted date of c. 10 Ma. Furthermore, we show that stilt-legged horses, commonly regarded as Old World migrants related to the hemionid asses of Asia, were in fact an endemic North American lineage. Finally, our data suggest that there were fewer horse species in late Pleistocene North America than have been named on morphological grounds. Both caballine and stilt-legged lineages may each have comprised a single, wide-ranging species.     

Ancient DNA Clarifies the Evolutionary History of American Late Pleistocene Equids

Hippidions are past members of the equid lineage which appeared in the South American fossil record around 2.5 Ma but then became extinct during the great late Pleistocene megafaunal extinction. According to fossil records and numerous dental, cranial, and postcranial characters, Hippidion and Equus lineages were expected to cluster in two distinct phylogenetic groups that diverged at least 10 MY, long before the emergence of the first Equus. However, the first DNA sequence information retrieved from Hippidion fossils supported a striking different phylogeny, with hippidions nesting inside a paraphyletic group of Equus. This result indicated either that the currently accepted phylogenetic tree of equids was incorrect regarding the timing of the evolutionary split between Hippidion and Equus or that the taxonomic identification of the hippidion fossils used for DNA analysis needed to be reexamined (and attributed to another extinct South American member of the equid lineage). The most likely candidate for the latter explanation is Equus (Amerhippus) neogeus. Here, we show by retrieving new ancient mtDNA sequences that hippidions and Equus (Amerhippus) neogeus were members of two distinct lineages. Furthermore, using a rigorous phylogenetic approach, we demonstrate that while formerly the largest equid from Southern America, Equus (Amerhippus) was just a member of the species Equus caballus. This new data increases the known phenotypic plasticity of horses and consequently casts doubt on the taxonomic validity of the subgenus Equus (Amerhippus).     

Patterns of body size changes in fossil and living Equini (Perissodactyla)

The importance of body mass prediction from several cranial, dental and appendicular variables in living Equini are studied. Relationships between the body mass changes and the ecogeographic picture of Equini evolution are also analysed. The metapodial and phalanx variables, particularly antero-posterior diameters, are better correlated with body mass than cranial variables in living Equini. Large sized species are correlated with cold climates, open habitats and/or soft soils; small ones are correlated with warm climates, more closed habitats and/or hard soils. Pleistocene horses from Europe and Africa follow an evolutionary trend opposite to their North American counterparts, from larger sized species to smaller ones. In South America the pattern of body size is different to those of the other continents. Species of Hippidion reaching large body mass, whereas some species of Equus, E. andium , follow a diminishing trend.     

Review of horses in Paleoindian sites of the Americas

Analysis of the morphological characters in North and South American horses present during Paleoindian time indicates that at least eight Equus ecospecies occurred in North America. In South America, Equus had radiated into four ecospecies, Hippidion had one, and Onohippidium had three geographically separate ecospecies. These species are found in archeological deposits ranging from ca. 13,000 to 8,000 yr B.P., in tropical habitats as well as in the high Andean and Patagonian colder ecotopes.     

Effects of Fungal Inocula and Habitat Conditions on Alder and Eucalyptus Leaf Litter Decomposition in Streams of Northern Spain

We investigated how fungal decomposer (aquatic hyphomycetes) communities colonizing alder and eucalyptus leaf litter respond to changes in habitat characteristics (transplantation experiment). We examined the breakdown of leaf materials and the associated fungal communities at two contrasting sites, a headwater stream (H) and a midreach (M). Agroforestry increased from headwater to midreach. One month after the start of experiments at both sites, some leaf samples from the midreach site were transplanted to the headwater site (M–H treatment). Although both sites showed similar dissolved inorganic nutrient concentrations, eucalyptus leaves initially incubated at the midreach site (M, M–H) increased their breakdown rate compared to those incubated along the experiment at the headwater site (H). Alder breakdown rate was not enhanced, suggesting that their consumption was not limited by nutrient availability. Sporulation rates clearly differed between leaf types (alder > eucalyptus) and streams (H > M), but no transplantation effect was detected. When comparing conidial assemblages after transplantation, an inoculum effect (persistence of early colonizing species) was clear in both leaf species. Substrate preference and shifts in the relative importance of some fungal species along the process were also observed. Overall, our results support the determining role of the initial conditioning phase on the whole litter breakdown process, highlighting the importance of intrinsic leaf characteristics and those of the incubation habitat.     

Hemiptelea mikii sp. nov. (Ulmaceae), fossil fruits and woods from the pleistocene of central Japan

A new fossil species,Hemiptelea mikii, is described on the basis of fruits from the Pleistocene of central Japan. It is distinguished fromH. davidii, the only extant species of the genus restricted to Korea and China, in having shorter fruits. Fossil woods discovered from the same horizon differ from the extant one in some anatomical characteristics, and are assigned to the new fossil species. Taken together with earlier records of fossil fruit occurrence in the early and the middle Pleistocene of central Japan, the latest finding of fossil fruits and woods from the last glacial sediments (ca. 50,000 years ago) at Kita-egota site of Tokyo suggests thatH. mikii was widespread in central Japan throughout the Pleistocene and survived until as late as the Last Glacial age.     

NEW SPECIES OF HALIMEDA: A TAXONOMIC REAPPRAISAL12

A study of new Halimeda material available from the International Indian Ocean Expedition, and of type and other specimens not previously available to me, further indicated that Halimeda opuntia is a composite of species rather than a single species. The characteristics of some of its infraspecific taxa differ sufficiently from typical H. opuntia that I have elevated them to species. Extended diagnoses of three, H. hederacea, H. minima, and H. distorta, are given in this paper. Some characteristics new in Halimeda taxonomy are introduced, and distinguishing macroscopic and microscopic characteristics for the new species are discussed. Available ecological data are included.     

A molecular perspective on the phylogeny of the Hyla pulchella species group (Anura, Hylidae)

A molecular phylogenetic analysis of the Hyla pulchella species group was performed to test its monophyly, explore the interrelationships of its species, and evaluate the validity of the taxa that were considered subspecies of H. pulchella. Approximately 2.8 kb from the mitochondrial genes 12s, tRNA valine, 16s, and Cytochrome b were sequenced. The analysis included 50 terminals representing 10 of the 14-15 species currently recognized in the H. pulchella group, including samples from several localities for some taxa, several outgroups, as well as two species previously suspected to be related with the group (Hyla guentheri and Hyla bischoffi). The results show that the H. pulchella and Hyla circumdata groups are distantly related, and, therefore, should be recognized as separate groups. As currently defined, the H. pulchella group is paraphyletic with respect to the Hyla polytaenia group; therefore, we recognize the Hyla polytaenia clade in the H. pulchella group. Two subspecies of H. pulchella recognized by some authors are considered full species including Hyla pulchella riojana because it is only distantly related to H. pulchella, and Hyla pulchella cordobae because molecular and non-molecular evidence suggests that it is specifically distinct. With the inclusion of the H. polytaenia clade, H. guentheri, and H. bischoffi, and the recognition of the two former subspecies of H. pulchella as distinct species, the H. pulchella group now comprises 25 described species. All representatives of the H. pulchella group with an Andean distribution are monophyletic and nested within a clade from the Atlantic forest from south-southeastern Brazil/northeastern Argentina, and Cerrado gallery forest from central Brazil.     

类诺卡氏属放线菌的研究进展

Prauser H.最初于1976年从土壤中分离到17株诺卡氏形态放线菌,综合形态、生理生化特性和部分化学分类特征的研究结果,提议建立了一个新属——类诺卡氏属(Nocardioides),并以新种白色类诺卡氏菌(N.albus)为典型种。之后,随着分离、纯培养和分类方法的发展,越来越多的新成员从各种不同环境中分离得到。尽管这些菌来源广泛,形态和生理生化等特征各异,但他们拥有共同的属的特征。过去的50年中,随着放线菌研究的发展,该属中部分成员历经了分类地位的变迁和修订。到目前为止,该属共收纳了56个有效描述种。类诺卡氏属(Nocardioides)放线菌在农业、工业、化工业等方面也曾有应用研究报道。本文就类诺卡氏属放线菌的建立依据,属的特征,属内种的分布和变更以及它们在工农业上的应用研究前景及进展进行了综述。     

Stream continuum and metabolic rate in the larvae of five species of Hydropsyche (Trichoptera)

The effects of temperature on the metabolic rate of five species of Hydropsyche larvae belonging either to the rhithron (Hydropsyche dinarica, H pellucidula and H siltalat) or to the potamon (H contubernalis and H modesta) have been studied The total amplitude of the metabolic rate between 5 and 25°C is higher in the larvae inhabiting the potamon than those of rhithron (particularly in H siltalat and H dinarica) The shapes of the metabolism temperature curves (M/T curves) of H contubernalis and H modesta differ from each other, although they live in the same habitat and are closely related A comparison with some species of Gammarus suggests a relationship between metabolic rate and the variability of environmental conditions     

Larval identification of species and subspecies of the genus Hyalomma (Acari: Ixodidae) from Russia and neighbouring territories

The following species and subspecies of Hyalomma Koch, 1844 are recorded from Russia and neighbouring territories, including those involved in natural foci of tick-borne diseases: H. (Hyalomma) aegyptium (Linnaeus, 1758), H. (Euhyalomma) dromedarii Koch, 1844, H. (Euh.) asiaticum asiaticum Schulze et Schlottke, 1930, H. (Euh.) asiaticum caucasicum Pomerantzev, 1940, H. (Euh.) asiaticum kozlovi Olenev, 1931, H. (Euh.) anatolicum Koch, 1844, H. (Euh.) excavatum Koch, 1844, H. scupense Schulze, 1918, H. (Euh.) marginatum marginatum Koch, 1844, H. (Euh.) marginatum turanicum Pomerantzev, 1946, and H. (Euh.) marginatum rufipes Koch, 1844. The geographic distribution and host-parasite relationships of each taxon are discussed. Species characters of the larval stage, that can be distinguished using light microscopy, are found to be very few. These characters include shape of scutum, shape and rate of hypostome denticulation, shape and rate of the development of spurs on coxae I to III. Measurements of some morphological structure and their rations show statistically significant differences between some closely related species, even if qualitative discriminating characters are unknown. Only measurements and their ratios can be used for the discrimination of larval H. anatolicum from larval H. excavatum, because qualitative discriminating features have not been found for these species. The complex structure of the subspecific morhological differentiation of all parasitic stages in the polymorphic species H. asiaticum and H. marginatum is revealed. This structure probably reflects some peculiarities of the microevolutionary processes. Identification key for the larval stage of seven Hyalomma species is provided.     

Investigation of the mechanism of the methylmalonyl-CoA mutase reaction with the substrate analogue: ethylmalonyl-CoA.

1. Ethylmalonyl-CoA was found to be a substrate for methylmalonyl-CoA mutase from Propionibacterium shermanii, the product being mainly (2R)-methylsuccinyl-CoA along with some (2S)-diastereoisomer. 2. The relevant 1H-nuclear magnetic resonance signals of methylsuccinic acid and of its dimethyl ester were assigned to the diastereotopic methylene hydrogens using sterospecifically dideuterated specimens of known configuration. 3. [2(-2)H1]Ethylmalonyl-CoA was converted by methylmalonyl-CoA mutase in 2H2O mainly to (2R, 3S)-[3(-2)H1]methylsuccinyl-CoA. No dideuterated product was observed. 4. Starting from (1R)-[1(-2)H1]-ethathanol, (1S)-[1(-2)H1]ethanol and [2H6] ethanol the following deuterated specimens of ethylmalonic acid were synthesised and characterised: (3S)-[3(-2)H1], (3R)-[3(-2)H1] and [3(-2)H2, 4(-2)H3], respectively. 5. Conversion of (3S)-[3(-2)H1]-ethylmalonyl-CoA (70% 2H1 and 2% 2H2 species) on the mutase in water afforded mainly (2R)-[2(-2)H1]methylsuccinyl-CoA along with some (2S)-diastereoisomer. No deuterium loss was observed. 6. Methylmalonyl-CoA mutase converted (3R)-[3(-2)H1]ethylmalonyl-CoA (81% 2H1 and 2% 2H2 species) to the following methylsuccinyl-CoA species: 33% [3(-2)H1], the deuterium being in the threo position with respect to the methyl group; 21% [2(-2)H1]; 46% unlabelled. The ratio of the species with (2R) and (2S) configuration was about 60:40. 7. Reaction of [3(-2)H2, 4(-2)H3]ethylmalonyl-CoA (94.5% [2H5] species) with the mutase gave the following labelled methylsuccinyl-CoA species:53.4% [methyl-2H3, 2(-2)H1, 3(-2)H1], the 3-deuterium being in the threo position with respect to the methyl group; 37.6% [methyl-2H3, 2(-2)H1]; 5% [methyl(-2)H3, 2(-2)H1, 2(-2)H1, 3(-2)H1] the 3-deuterium being in erythro position with respect to the methyl group; 4% [methyl(-2)H3, 3(-2)H1]. The ratio of the species with (2R) and (2S) configuration was about 70:30. 8. Implications of these findings for the mechanism of the rearrangements catalysed by coenzyme B12 are discussed.     

Two new species of Nippostrongylinae (Nematoda,Trichostrongylina) parasites of Cricetomys gambianus and Arvicanthis niloticus (Muridae) from Senegal

Two new Nippostrongylinae (Heligmosomoidea, Heligmonellidae) originating from Senegal are described. Heligmonina bioccai n. sp., a parasite of Cricetomys gambianus (Cricetomyinae) found in the surroundings of Dakar and Neoheligmonella bai n. sp., a parasite of Arvicanthis niloticus (Murinae) from the Province of Richard Toll. H. bioccai n. sp. is related to H. hybomysi (Durette-Desset, 1966) a parasite of Hybomys univittatus from the Central African Republic by some characteristics of the caudal bursa and of the synlophe. They are the only two species with the same pattern of caudal bursa: type 1-3-1 for the right lobe, 2-3 for the left lobe, and with the same number and disposition of the cuticular ridges at mid-body in the female. The two species are differentiated by the size (three times smaller in H. hybomysi), the ratio of spicule length on body length (7.6% versus 17% in H. hybomysi) and by a different synlophe in male and posterior part of female. N. bai n. sp. is differentiated from the closely related species N. dielmensis Diouf, Ba and Durette-Desset, 1997, also a parasite of Arvicanthis niloticus from Senegal by rays 8 arising asymmetrically on the dorsal ray and by the deirids situated at the same level as the excretory pore.     

强壮水螅的特征及其与寡水螅的种间差别问题

一种广泛分布于黑龙江省的大型具柄水螅被暂定为强壮水螅Hydra robusta(IT(?) 1947)。这一中国品系与IT(?)(1947)在日本报告的新种主要特征相同,包括具有精巢乳头。只是精巢乳头不稳定。在实验室条件下第一次有性生殖时每个雄体都发生精巢乳头,但第二次有性生殖时,同一群的后代可全部失去精巢乳头。这是介于强壮水螅与寡水螅Hydra oligactis Pallas(1766)之间的中间性状。从而导致作者做出结论,认为过去其他学者所主张的,以精巢乳头的有无做为鉴别特征来区分强壮水螅和寡水螅是不可靠的。因此,本文又检验了此种水螅的体细胞染色体,证明2n=30,其中第二对染色体上有明显近中位置的次缢痕,最小染色体的长度为最大染色体长度的二分之一以上。这些可做为此种水蝗的鉴别特征。对Niiyama(1944)和Datta(1970)在寡水螅上所做的染色体研究也做了比较及讨论。     

A review of Asian Hediste species complex (Nereididae, Polychaeta) with descriptions of two new species and a redescription of Hediste japonica (Izuka, 1908)

Three Asian species of the genus Hediste (Nereididae, Polychaeta, Annelida), including two new species, are reviewed. Hediste japonica (Izuka, 1908) was redescribed based on recently discovered type material and on additional specimens newly collected from the Ariake Sea in Japan and the west coast of Korea. Two new species, H .  diadroma and H. atoka , were described based on specimens collected from Japan. These three species are morphologically similar, but distinguishable by some differences in parapodial and chaetal morphology, at least at the sexually mature stage. The presence of homogomph falcigers and the absence of heterogomph spinigers are unique characteristics of H. japonica among this genus. Inconspicuous epitokous metamorphosis occurred as a slight enlargement of the eyes and parapodial ligules in mature adults of H. diadroma sp. nov. and H. japonica in combination with their reproductive swarming and pelagic larval development. The epitoke-specific sesquigomph spinigers were added in mature adults of H. diadroma sp. nov., while the number of ordinary homogomph spinigers increased in some adults of H. japonica. Epitokous metamorphosis in the Hediste species was compared with that in other nereidid genera. No epitokous metamorphosis was observed in H. atoka sp. nov., corresponding to its reproduction without swarming and to its development without a planktonic larval stage. Significant differences in paragnath numbers in the maxillary ring of the proboscis were found among the three species, suggesting different feeding habits. In Japan, the present distribution of H. japonica is restricted to muddy tidal flats in the inner part of the Ariake Sea, probably due to recent human impact, while the other two species are widespread.  © 2003 The Linnean Society of London. Zoological Journal of the Linnean Society, 2003, 137, 403−445     

New species of avian Hepatozoon (Apicomplexa: Haemogregarinidae) and a re-description of Hepatozoon neophrontis (Todd & Wohlbach, 1912) Wenyon, 1926

Seven new species of avian Hepatozoon, H. lanis, H. malacotinus, H. numidis, H. pittae, H. estrildus, H. sylvae and H. zosteropis, respectively, are described from the Laniinae, Malaconotinae, Numidinae, Pittidae, Poephilinae, Sylviinae and Zosteropidae. Hepatozoon adiei Hoare, 1924 is synonymised with Hepatozoon neophrontis (Todd &; Wolbach, 1912) Wenyon, 1926 from the Accipitridae and H. neophrontis re-described. Four species of Hepatozoon described by de Beaurepaire Aragão from Brazil are reviewed and Hepatozoon tanagrae (de Beaurepaire Aragão, 1911) Hoare, 1924 is synonymised with H. rhamphocoeli (de Beaurepaire Aragão, 1911) Hoare 1924 and H. brachyspizae (de Beaurepaire Aragão) Hoare, 1924 with H. paroariae (de Beaurepaire Aragão, 1911) Hoare, 1924. Illustrations and measurements for Hepatozoon albatrossi Peirce &; Prince, 1980, H. atticorae (de Beaurepaire Aragão, 1911) Hoare, 1924 and H. parus Bennett &; Peirce, 1989 are also presented to complete the review of the known avian species. The value of some potential morphological characteristics for distinguishing species of Hepatozoon is discussed.     

A Comparative Analysis of the Morphology of Holosticha corlissi N. Sp. (Ciliophora,Hypotrichida) and Related Species1

ABSTRACT The morphology of the hypotrichous ciliate, Holosticha corlissi n. sp., found in the moss Calliergonella cuspidata taken from the beech wood of Montejo de la Sierra (Madrid, Spain) is described. Some characteristics (organization of the mid-ventral, frontal and fronto-terminal cirri, presence of a buccal cirrus and the number of transverse cirri) are sufficiently different from the closely related species H. intermedia, H. sigmoidea and H. xanthichroma to suggest that it is a separate species, although its body shape, nucleus and buccal apparatus are very similar.     

The Hyparrhenia involucrata—H. subplumosa (Gramineae) complex in Nigeria: morphological and cytological characterization

Hyparrhenia involucrata Stapf is an annual with diploid, aneuploíd, tetraploid and hexaploid chromosome races on a base of x = 10, whilst M. subplumosa Stapf is known to be tetraploid and perennial. The two species overlap considerably in their vegetative and floral attributes. Whilst the floral characteristics (such as number of awns and sex of imperfect flowers) are fairly constant within H. involucrata , they are quite variable in H. subplumosa : the evolutionary significance of some of these variations is discussed. Some of the observations on size, variability and fertility of pollen grains are interpreted using data from chromosome numbers and meiotic behaviour. Preliminary observations on the hybrids between a diploid race of H. involucrata and H. subplumosa indicate that the genomes of the two species are highly homologous and that perennial habit is a dominant trait controlled by a single gene.     

Untangling Nucleotide Diversity and Evolution of the H Genome in Polyploid Hordeum and Elymus Species Based on the Single Copy of Nuclear Gene DMC1

Numerous hybrid and polypoid species are found within the Triticeae. It has been suggested that the H subgenome of allopolyploid Elymus (wheatgrass) species originated from diploid Hordeum (barley) species, but the role of hybridization between polyploid Elymus and Hordeum has not been studied. It is not clear whether gene flow across polyploid Hordeum and Elymus species has occurred following polyploid speciation. Answering these questions will provide new insights into the formation of these polyploid species, and the potential role of gene flow among polyploid species during polyploid evolution. In order to address these questions, disrupted meiotic cDNA1 (DMC1) data from the allopolyploid StH Elymus are analyzed together with diploid and polyploid Hordeum species. Phylogenetic analysis revealed that the H copies of DMC1 sequence in some Elymus are very close to the H copies of DMC1 sequence in some polyploid Hordeum species, indicating either that the H genome in theses Elymus and polyploid Hordeum species originated from same diploid donor or that gene flow has occurred among them. Our analysis also suggested that the H genomes in Elymus species originated from limited gene pool, while H genomes in Hordeum polyploids have originated from broad gene pools. Nucleotide diversity (π) of the DMC1 sequences on H genome from polyploid species (π = 0.02083 in Elymus, π = 0.01680 in polyploid Hordeum) is higher than that in diploid Hordeum (π = 0.01488). The estimates of Tajima''s D were significantly departure from the equilibrium neutral model at this locus in diploid Hordeum species (P<0.05), suggesting an excess of rare variants in diploid species which may not contribute to the origination of polyploids. Nucleotide diversity (π) of the DMC1 sequences in Elymus polyploid species (π = 0.02083) is higher than that in polyploid Hordeum (π = 0.01680), suggesting that the degree of relationships between two parents of a polyploid might be a factor affecting nucleotide diversity in allopolyploids.