Anatomy of the Muhlenbergia Montana complex (Poaceae)

Leaf anatomical data from 13 taxa of the Muhlenbergia montana complex were surveyed, and 18 critical characters were found. Results obtained from the phenetic analysis of anatomical data have given independent data to compare with the morphological, phytogeographical, and flavonoid data (previously reported) in determining the relationships of the species. An anatomical dendogram illustrates a close corroboration. Leaf anatomy clearly supports the recognition of a close relationship among the two taxa — M. virescens and M. quadridentata—as has been suggested in previous reports. Therefore, a change of level is suggested in which M. quadridentata (H.B.K.) Kunth is proposed here as M. virescens (H.B.K.) Kunth ssp. quadridentata (H.B.K.) Herrera (comb. nov.).     

Three new species of Muhlenbergia and Uniola (Poaceae) from Northern Peru

Three new grass species, Muhlenbergia coxamarcensis, M. maxima and Uniola peruviana are described from Northern Peru. Their affinities and geographical distribution are briefly discussed.     

Multivariate analysis of morphological and anatomical characters of Calophyllum (Calophyllaceae) in South America

Calophyllum (Calophyllaceae), previously placed in Clusiaceae, is easily recognizable by its opposite entire leaves with close parallel venation alternating with resin canals. However, distinction between species has been difficult, because of infraspecific variation in tepal and stamen number and resemblance among species that share similar habitats. Here, I report the results of multivariate analyses of morphological and anatomical characters for Calophyllum in South America, and provide a taxonomic treatment for the genus in South America, the first since that of Vesque in 1893. Thirteen preliminary morphogroups were identified. Thirty‐two morphological characters of the leaf, flower and fruit from 401 specimens, and 17 anatomical leaf characters from 45 specimens were measured and analysed using principal component analyses (PCAs) and discriminant analyses (DAs). PCAs were used to find groups and DAs were used to validate those PCAs that were potential groups. Two main subgroups were identified in the general analysis. Subgroup M1 has terete stems and smaller leaves and flowers than subgroup M2, which, instead, has quadrangular stems. Only subgroup M2 showed distinctive clusters in regional and local analyses. Distinctive clusters and morphological and anatomical characters helped us to recognize four species in South America, including a new species, Calophyllum pubescens sp. nov. . In addition, a new species, Calophyllum mesoamericanum sp. nov. , is described from Central America. © 2013 The Linnean Society of London,     

Post-natal ontogeny of the mandible and ventral cranium in <Emphasis Type="Italic">Marmota</Emphasis> species (Rodentia,Sciuridae): allometry and phylogeny

Post-natal ontogenetic variation of the marmot mandible and ventral cranium is investigated in two species of the subgenus Petromarmota (M. caligata, M. flaviventris) and four species of the subgenus Marmota (M. caudata, M. himalayana, M. marmota, M. monax). Relationships between size and shape are analysed using geometric morphometric techniques. Sexual dimorphism is negligible, allometry explains the main changes in shape during growth, and males and females manifest similar allometric trajectories. Anatomical regions affected by size-related shape variation are similar in different species, but allometric trajectories are divergent. The largest modifications of the mandible and ventral cranium occur in regions directly involved in the mechanics of mastication. Relative to other anatomical regions, the size of areas of muscle insertion increases, while the size of sense organs, nerves and teeth generally decreases. Epigenetic factors, developmental constraints and size variation were found to be the major contributors in producing the observed allometric patterns. A phylogenetic signal was not evident in the comparison of allometric trajectories, but traits that allow discrimination of the Palaearctic marmots from the Nearctic species of Petromarmota are present early in development and are conserved during post-natal ontogeny.     

Allozyme diversity within and divergence among species ofTolpis(Asteraceae-Lactuceae) in the Canary Islands: systematic, evolutionary, and biogeographical implications

Plants endemic to oceanic islands represent some of the most unusual and rare taxa in the world. Enzyme electrophoresis was used to assess genetic diversity within and divergence among all endemic species of a small genus of plants on the Canary Islands. Our results show that the genus Tolpis is similar to many other island groups in having generally low allozyme divergence among species, with the highest divergence found among four groups of endemics. The two rare and highly localized species T. glabrescens and T. crassiuscula are each divergent from all other species in the Canaries. Tolpis coronopifolia is also divergent at allozyme loci; this is the only endemic species that is a self-compatible annual (or weak biennial). A large, morphologically variable species complex consisting of T. laciniata and T. lagopoda together with several named and unnamed morphological variants shows low allozyme divergence among its elements. The evolution of polyploidy from diploid ancestors in situ in oceanic archipelagos is uncommon, but the tetraploid T. glabrescens is an exception. Allozyme data do not implicate any extant diploid Tolpis species as parents of the polyploid. It is possible that T. glabrescens originated early in the evolution of Tolpis in the Canary Islands and that its parents are now extinct. The nonendemic T. barbata shows no greater divergence from the Canary Island endemics than some endemics exhibit among themselves. Both changes in allele frequencies and unique alleles are responsible for genetic divergence among species of Tolpis.     

The division between fast- and slow-growing species corresponds to natural relationships among the mycobacteria.

Comparative 16S rRNA sequencing was used to infer the phylogenetic relationships among selected species of mycobacteria and related organisms. The phylogeny inferred reflects the traditional classification, with major branches of the phylogenetic tree in general correspondence to the four Runyon groups and with numerical classification analyses. All the mycobacterial species compared, with the exception of M. chitae, are closely related (average similarity values greater than 95%). The slow growers form a coherent line of descent, distinct from the rapid growers, within which the overt pathogens are clustered. The distant relationship between M. chitae and the remaining mycobacteria suggests that this organism is incorrectly classified with the mycobacteria. M. paratuberculosis 18 was indistinguishable from M. avium-M. intracellulare-M. scrofulaceum serovar 1 by this analysis.     

Anatomical Features of Modellnaia siamensis (Mollusca, Bivalvia, Unionidae)

Although conchologically an etheriid mussel, M. siamensis from northeastern Thailand is, according to anatomical and larval features, an unionid. Its unique character states among the Unionidae are: relatively distant spacing of septa in all four demibranchs in both, males and females, absence of a foot in adults, and generation of subelliptical glochidial larvae. This species is seemingly a phylogenetic relic.     

Molecular phylogenies in the genus Mus: Comparative analysis of electrophoretic, scnDNA hybridization, and mtDNA RFLP data

In this paper, we present data on murid rodents obtained by three major techniques used in biochemical systematics today: protein electrophoresis, scnDNA hybridization and mtDNA RFLP. The data have been analysed by both phenetic and cladistic methods and results of the three techniques were compared with one another. Four clear major levels of divergence (or nodes) can be recognized by all methods. Node 1 groups four subspecies of M. musculus ( domesticus, bactrianus, castaneus and musculus ). Node 2 groups four species: M. musculus, M. spretus, M. spicilegus and M. spretoides . Node 3 groups the stem of node 2 and three strictly Oriental species ( M. caroli, M. cervicolor and M. cookii ) Node 4 groups the previous lineages with Oriental Pyromys and Coelomys and the Ethiopian Nannomys . However, the relationships within each level cannot be resolved without ambiguity. We argue that this is not due to the resolutive power of our methods, but to a biological reality, that is successive adaptive radiations marked by quasi-simultaneous speciation events linked with geographical colonization. Our estimation of divergence time between different taxa showed that the genus Mus is very young. The youngest 'bona fide' species are 1.1 Myr old, or even less than 0.3 Myr if one takes into consideration the two sibling species M. spicilegus and M. spretoides . It appears that mtDNA evolves three to six times faster than scnDNA. The zoogeographical history of the genus can be reconstructed as a séries of adaptative radiations leading to the present day distribution of the Palaearctic, Oriental, and Ethiopian groups of taxa.     

Nonconvergence in the evolution of primate life history and socio-ecology

The goal of this study was to investigate the extent of convergence in four basic life history and socio-ecological traits among the primates of Africa, Asia, South America and Madagascar. The convergence hypothesis predicts that similar abiotic conditions should result in similar adaptations in independent taxa. Because primates offer a unique opportunity among mammals to examine adaptations of independent groups to tropical environments, we collected information on body mass, activity pattern, diet and group size from all genera for quantitative tests of this hypothesis. We revealed a number of qualitative and quantitative differences among the four primate groups, indicating a lack of convergence in these basic aspects of life history and socio-ecology. Our analyses demonstrated that New World primates are on average significantly smaller than primates in other regions and characterized by a lack of species larger than about 10 kg. Madagascar harbours significantly more nocturnal species than the other regions and is home to all but one of the primates with irregular bursts of activity. Asia is the only region with strictly faunivorous primates, but lacks primarily gummivorous ones. The Neotropics are characterized by the absence of primarily folivorous primates. Solitary species are not represented in the New World, whereas solitary and pair-living species make up the majority of Malagasy primates. Lemurs live in significantly smaller groups than other primates, even after controlling for differences in body size. The lack of convergence among the major primate groups is neither primarily due to phylogenetic constraints as a result of founder effects, nor can it be sufficiently explained as a passive consequence of body size differences. However, because the role of adaptive forces, such as interspecific competition, predation or phenology in shaping the observed differences is largely unexplored, we conclude that it is premature to discard the convergence hypothesis without further tests.     

Spermatozoan morphology as a character for tardigrade systematics: comparison with sclerified parts of animals and eggs in eutardigrades

The male gamete, a cell widely used for evaluating phylogeny in different animal groups, remains relatively unknown in tardigrades. In this paper the spermatozoa of thirteen species of eutardigrades among four genera and three families is evaluated in order to determine whether sperm morphology can be used as a taxonomic character. Spermatozoa of Amphibolus volubilis and A. weglarskae are very similar and this resemblance is congruent with the remarkable similarity of sclerified parts of the species. In addition, the spermatozoa of eight species of the genus Macrobiotus were examined yielding two groups showing strong intragroup similarities. The first group includes M. pseudohufelandi, M. sandrae, M. macrocalix, M. terminals and M.joannae , and the second M. richtersi, M. areolatus and M. harmsworthi. Again, these groupings were congruent with those determined by analysis of sclerified structures. In contrast, a marked similarity was found between the spermatozoa ot Diphascon (Adropion) scoticum and Platicrista angustata , whereas Diphascon (Diphascon) humicus was appreciably different from both species. Resemblances found in this study between spermatozoa and sclerified body parts suggests that the spermatozoa are suitable characters for use in systematic studies.     

Allelic variation in the amphitropical disjunct Muhlenbergia torreyi (Poaceae: Muhlenbergiinae)

Muhlenbergia torreyi occurs in the southwestern United States, northern Mexico, and northwestern Argentina. Allozyme data were used to evaluate genetic diversity within and among populations of this amphitropical disjunct species. Electrophoretic examination of 22 putative enzyme loci in 15 populations revealed high levels of genetic variation (P ranging from 64.7 to 82.4;H from 0.527 to 0.757) and high levels of genetic diversity (F ranging from −0.584 to −0.939). All populations possess high levels of heterogeneity (F _1S approaching −1, mean of −0.837) and exhibit lower levels of genetic fixation among populations (F _ST mean of 0.127). A comparison of genetic identity values among populations from North and South America indicates that the genetic variation is slightly greater (I=0.93) in North America than in South America (I=0.96). A total of 51 alleles were shared among all populations, and four unique alleles were detected: two from North American populations and two from South America. It seems likely thatMuhlenbergia torreyi has dispersed to South America recently, because the populations there are less variable. Chromosome numbers, not determined by the authors, of 2n=20, 21 forM. torreyi and 2n=80, 82 forM. arenicola are reported.Muhlenbegia arenicola is first reported from South America.

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Resumen   Muhlenbergia torreyi habita en el suroeste de Estados Unidos, norte de México, y noreste de Argentina. Mediante el análisis de alozimas se evaluó la diversidad genética dentro y entre poblaciones de esta especie, que es disjunctiva anfitropical. El exámen electroforético de 22 loci putativos enzimáticos en 15 poblaciones, reveló altos niveles de variación genética (P varía de 64.7 a 82.4;H varía de 0.527 a 0.757) y altos niveles de diversidad genética (F varía de −0.584 a −0.939). Todas las poblaciones poseen altos niveles de heterogeneidad dentro de las mismas poblaciones (F _IS cerca −1, media de −0.837) y exhiben bajos niveles de fijación genética entre poblaciones (F _ST media de 0.127). Una comparación de valores de identidad genética entre poblaciones de Norte y Sudamérica indican que la variación genética es un poco mayor (I=0.93) en Norte América que en Sudamérica (I=0.96). Las poblaciones poseían un total de 51 alelos en común y se detectaron cuatro alelos únicos; dos en las poblaciones norteamericanas y dos en las poblaciones sudamericanas. Probablemente,Muhlenbergia torreyi ha sido dispersada recientemente hacia Sudamérica porque esta poblacion es menos variable. El número de cromosomas, no determinado por los autores, de 2n=20, 21 paraM. torreyi and 2n=80, 82 paraM. arenicola son reportados.Muhlenbergia arenicola es reportada por primera vez en Sudamérica.

     

New evidence for parallel evolution of colour patterns in Malagasy poison frogs (Mantella)

Malagasy poison frogs of the genus Mantella are diurnal and toxic amphibians of highly variable and largely aposematic coloration. Previous studies provided evidence for several instances of homoplastic colour evolution in this genus but were unable to sufficiently resolve relationships among major species groups or to clarify the phylogenetic position of several crucial taxa. Here, we provide cytochrome b data for 143 individuals of three species in the Mantella madagascariensis group, including four newly discovered populations. Three of these new populations are characterized by highly variable coloration and patterns but showed no conspicuous increase of haplotype diversity which would be expected under a scenario of secondary hybridization or admixture of chromatically uniform populations. Several populations of these variable forms and of M. crocea were geographically interspersed between the distribution areas of Mantella aurantiaca and Mantella milotympanum. This provides further support for the hypothesis that the largely similar uniformly orange colour of the last two species evolved in parallel. Phylogenies based on over 2000 bp of two nuclear genes (Rag-1 and Rag-2) identified reliably a clade of the Mantella betsileo and Mantella laevigata groups as sister lineage to the M. madagascariensis group, but did not support species within the latter group as monophyletic. The evolutionary history of these frogs might have been characterized by fast and recurrent evolution of colour patterns, possibly triggered by strong selection pressures and mimicry effects, being too complex to be represented by simple bifurcating models of phylogenetic reconstruction.     

Physico‐chemical variables determining the invasion risk of freshwater habitats by alien mollusks and crustaceans

The aim of this study was to assess the invasion risk of freshwater habitats and determine the environmental variables that are most favorable for the establishment of alien amphipods, isopods, gastropods, and bivalves. A total of 981 sites located in streams and rivers in Germany. Therefore we analyzed presence–absence data of alien and indigenous amphipods, isopods, gastropods, and bivalves from 981 sites located in small to large rivers in Germany with regard to eight environmental variables: chloride, ammonium, nitrate, oxygen, orthophosphate, distance to the next navigable waterway, and maximum and minimum temperature. Degraded sites close to navigable waters were exposed to an increased invasion risk by all major groups of alien species. Moreover, invaded sites by all four groups of alien species were similar, whereas the sites where indigenous members of the four groups occurred were more variable. Increased temperature and chloride concentration as well as decreased oxygen concentration were identified as major factors for the invasibility of a site. Species‐specific analyses showed that chloride was among the three most predictive environmental variables determining species assemblage in all four taxonomic groups. Also distance to the next navigable waterways was similarly important. Additionally, the minimum temperature was among the most important variables for amphipods, isopods, and bivalves. The bias in the occurrence patterns of alien species toward similarly degraded habitats suggests that the members of all four major groups of freshwater alien species are a non‐random, more tolerant set of species. Their common tolerance to salinity, high temperature, and oxygen depletion may reflect that most alien species were spread in ballast water tanks, where strong selective pressures, particularly temperature fluctuations, oxygen depletion, and increased salinity may create a bottleneck for successful invasion. Knowledge on the major factors that influence the invasion risk of a habitat is needed to develop strategies to limit the spread of invasive species.     

Getting a grip on tetrapod grasping: form,function, and evolution

Human beings have been credited with unparalleled capabilities for digital prehension grasping. However, grasping behaviour is widespread among tetrapods. The propensity to grasp, and the anatomical characteristics that underlie it, appear in all of the major groups of tetrapods with the possible exception of terrestrial turtles. Although some features are synapomorphic to the tetrapod clade, such as well‐defined digits and digital musculature, other features, such as opposable digits and tendon configurations, appear to have evolved independently in many lineages. Here we examine the incidence, functional morphology, and evolution of grasping across four major tetrapod clades. Our review suggests that the ability to grasp with the manus and pes is considerably more widespread, and ecologically and evolutionarily important, than previously thought. The morphological bases and ecological factors that govern grasping abilities may differ among tetrapods, yet the selective forces shaping them are likely similar. We suggest that further investigation into grasping form and function within and among these clades may expose a greater role for grasping ability in the evolutionary success of many tetrapod lineages.     

Analysis of phylogenetic relationship among five mulberry (Morus) species using molecular markers.

Species identification in mulberry (Morus) continues to be a point of great debate among scientists despite the number of criteria such as floral characters, wood, and leaf anatomical and biochemical characters used to identify the species within this genus. However, no consensus system of classification has emerged. Hence, an investigation was undertaken with inter-simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) markers to find out the possibility of using these DNA markers to confirm the identity of genotypes in a particular species. Fifteen ISSR and 15 RAPD primers generated 86% and 78% polymorphism, respectively, among 19 mulberry genotypes. The polymorphism among the species varied from 50% to 57% in ISSR markers and 31% to 53% in RAPD markers. Similarity coefficients were higher among the genotypes of M. latifolia, M. bombycis and M. alba. Cluster analyses separated genotypes of M. laevigata and M. indica from those of the other species. Population structure analysis of these species further showed high genetic differentiation coefficients (GST), high heterozygosity between two species (DST), and total heterozygosity among populations (Ht) coupled with considerably low gene flow (Nm) when M. laevigata was paired with other species. Based on these parameters and the result of cluster analysis it is concluded that M. laevigata can be considered as a separate species of mulberry, whereas the other four species may be grouped together and treated as subspecies.     

Assessing the utility of direct and indirect methods for estimating tropical tree age in the Western Ghats, India

The knowledge of tree age is important for understanding tree growth and forest dynamics. It may be estimated by ‘direct’ methods involving growth ring counts, or by ‘indirect’ methods involving field measurements of growth rates. Direct methods are considered more accurate, but it is not clear if they are appropriate for all species, notably from the humid tropics. In this paper we assess the occurrence of annual growth rings and their utility for age estimation in three tropical tree species, Acrocarpus fraxinifolius, Dalbergia latifolia (Fabaceae) and Syzygium cumini (Myrtaceae), growing in traditional shade coffee plantations of the southern Western Ghats, India. These species previously were described as having “indistinct or absent” growth rings. We used anatomical studies, field measurements and computational methods to characterise growth rings and assess similarities between directly and indirectly estimated tree ages. Our study revealed that annual growth rings were characterised by different sets of anatomical features per species and were most distinct in the fast-growing deciduous A. fraxinifolius. Growth rates measured in the field showed annual periodicity in all three species, and reflected annual rainfall-drought cycles in D. latifolia and S. cumini. Direct age estimates were most similar to indirect estimates in D. latifolia, and least so in S. cumini. The results of direct age estimation by counting rings are consistent with them being annual in nature in tropical species with distinct and reliable annual growth ring formation. However, for species with poorly defined growth rings, indirect age estimation methods might be more useful.     

Effect of nitrogen, water and neighbor density on the growth of Hesperis matronalis and two native perennials

Disturbance is a well-recognized catalyst of exotic species invasion, depriving or releasing resources into communities and favoring the spread of some invaders. Hesperis matronalis (dame’s rocket) is widespread in North America and has potential to become a major problem in natural communities due to anthropogenic influences. We used a target-neighbor design in a greenhouse to grow H. matronalis and native seedlings (Campanula rotundifolia and Muhlenbergia montana) at various levels of neighbor density, nitrogen and water. H. matronalis clearly reduced C. rotundifolia and M. montana aboveground growth and maintained its competitive advantage across all treatments. We expected H. matronalis to maximize its growth and have the greatest negative effect on native species under high resource conditions because ruderal species are able to take advantage of excess resources. H. matronalis demonstrated a clearly negative effect on native species, but a particular ability to outcompete native species at high resource levels depended on resource and native species identity. We also expected that the native species would not exploit excess resources as well as H. matronalis, instead growing better under ambient or low resource conditions because of local adaptation. Rather, M. montana benefited from high water inputs, inconsistent with plant strategies characteristic of stress tolerators. Information on the effects of H. matronalis on native plants in a controlled setting may aid land managers to understand its potential effects in natural communities.