The evolution of aquatic feeding in seals: insights from Enaliarctos (Carnivora: Pinnipedimorpha), the oldest known seal

The development of pierce‐feeding and loss of oral processing represented major adaptations for underwater feeding in marine mammals. We examined the evolution of pierce‐feeding and its association with changes in tooth spacing and tooth size to determine whether pierce‐feeding was practiced by the earliest known pinnipeds. Data on crown size and spacing in postcanine dentition were collected and 1) analysed by principal components analysis (PCA) to determine the tooth morphospace of arctoid carnivores, 2) analysed by least squares (LS) regression and phylogenetic independent contrasts (PIC) to determine what morphological variables were associated with increases in tooth spacing, and 3) used to reconstruct the evolution of feeding related traits within a phylogenetic context. The PCA analysis revealed that within arctoid carnivores, the greatest differences in morphospace were associated with pierce‐feeding, and the early‐diverging seal Enaliarctos was placed within the pinniped morphospace. Increased tooth spacing within Pinnipedia is a result of decreased postcanine crown size. When the evolution of dental characters is reconstructed, ‘enaliarctines’ were found to represent an intermediate stage in evolution between ‘fissiped’ and pinniped carnivores. They retained the limited tooth spacing of terrestrial carnivores, possessed postcanine crown lengths intermediate in size between pinnipeds and fissipeds, and possessed reduced heterodonty characteristic of crown pinnipeds. Our study indicated that pierce‐feeding evolved early within pinnipeds. This suggested either that pierce‐feeding evolved prior to the loss of mastication, or that pierce‐feeding evolved at the same time as loss of mastication, and well before simplification of the dentition was completed.     

Phylogenetic relationships among calyptraeid gastropods and their implications for the biogeography of marine speciation

Although calyptraeid gastropods are not well understood taxonomically, in part because their simple plastic shells are the primary taxonomic character, they provide an ideal system to examine questions about evolution in the marine environment. I conducted a phylogenetic analysis of calyptraeid gastropods using DNA sequence data from mitochondrial cytochrome oxidase I (COI) and 16S genes and the nuclear 28S gene. The resultant phylogeny was used to examine the biogeographic patterns of speciation in the Calyptraeidae. Parsimony and Bayesian analyses of the combined data sets for 94 calyptraeid operational taxonomic units and 24 outgroups produced well-resolved phylogenies. Both approaches resulted in identical sister-species relationships, and the few differences in deeper topology did not affect biogeographic inferences. The geographic distribution of the species included here demonstrate numerous dispersal events both between the Pacific and Atlantic oceans and across the equator. When parsimony is used to reconstruct the movement from the Pacific to the Atlantic oceans on the phylogeny, there are 12 transitions between oceans, primarily from the Pacific to the Atlantic. When the latitude is coded as north versus south of the equator, the most-parsimonious reconstruction gives the origin of calyptraeids in the north followed by 15 dispersal events to regions south of the equator and no returns to the north. Many clades of the most closely related species are either sympatric or occur along a single coastline. Closely related species can, however, occur in such divergent regions as Southern California and South Africa. There is little evidence for sister-species pairs or larger clades having been split by the Isthmus of Panama or the Benguela upwelling, but the East Pacific Barrier appears to separate the most basal taxa from the rest of the family.     

Infrageneric relationships within Pogostemon Desf. (Labiatae)

Cladistic and phenetic analyses of the morphology of 79 species of Pogostemon Desf. sens lato have been undertaken. The cladistic analysis included 135 character state differences encoded as 41 binary or multistate characters. The phenetic analysis included 52 metric variables and 54 binary variables. There is a very good correspondence between the results of cladistic and phenetic analyses based on different data sets. The existence of several clearly marked clades/clusters has been demonstrated. Some groups/clades are similar to those previously taxonomically recognized but the relationships and membership of infra-generic groups have been clarified by these analyses, validating a revised infra-generic classification which has been proposed.     

Geographic variation in diapause response of adult Rhipicephalus appendiculatus ticks

Diapause in adults of the African brown ear tick Rhipicephalus appendiculatus is dependent on latitude and stock origin. Lower latitude populations, that is, those nearer the equator, show no diapause response to long or short day exposure. Diapause response to short day lengths is found in higher latitude populations, further south, and increases with increasing latitude. Nearly all individuals in the southernmost population, used in this study, enter diapause under short and long day exposure which implies that the onset of diapause in this population is obligatory. Diapause termination in higher latitude populations is induced by increasing photo period, further north, but still south of the equator, diapause is terminated by ageing. The differences in diapausing behaviour of the different populations are discussed in relation to their climatic conditions. This revised version was published online in July 2006 with corrections to the Cover Date.     

Stock structure of Icelandic cod Gadus morhua L. based on otolith chemistry

Otolith chemistry was used to study the stock structure of Icelandic cod Gadus morhua . Otoliths were collected from spawning cod at 12 and 17 different spawning locations around Iceland during the spawning season in 2002 and 2003, respectively. The otolith elemental composition of cod spawning north and south of Iceland differed substantially from each other, as did spawning cod below and above 125 m depth at the main spawning ground in the south of Iceland. Otolith chemistry differed more between locations than among years within a location, indicating temporal stability between the 2 years. The Icelandic cod stock is managed as a single stock. These results suggest, however, that optimal fisheries management may require different management units than are currently present.     

Stock discrimination of the Japanese Spanish mackerel (Scomberomorus niphonius) based on the otolith shape analysis in the Yellow Sea and Bohai Sea

Geographic variability in sagittal otoliths shape of the Japanese Spanish mackerel (Scomberomorus niphonius) was studied to test whether stock discrimination might be possible using this method. It was hypothesized that S. niphonius would show little difference in otolith shape, likely as a result of mixing between seas. A total of 164 sagittal otoliths were collected from commercial fishing vessels between April and June 2010 in three spawning grounds, that of Qingdao in the middle Yellow Sea, Lvsi in the southern Yellow Sea, Huanghua in the the Bohai Sea. To minimize the potential effect of the fish size among the three fishing grounds, a narrow size range (400–550 mm fork length) was selected. The discriminant function analysis conducted with standardized otolith shape indices and Fourier harmonics produced classification success rates ranging from 57.0 to 88.2% and worked well in the separation between the Bohai Sea group and the Yellow Sea group. No significant differences were detected among the three groups for the Lvsi spawning grounds. The otolith variables showed a distinct gradual variation tendency with the movement of fish schools from south to north. The results suggest that stock from the Bohai Sea could be managed as a separate entity from those found in the Yellow Sea.     

QUANTITATIVE CHARACTERS IN PHYLOGENETIC ANALYSIS

Abstract— When analysing phylogcnetic relationships at low laxonomic levels it is often the ease that many of the features that can be used to separate taxa show continuous variation. The theoretical and practical problems for the use of such quantitative characters in phylogenetic analysis arc examined. Three methods of coding continuous data into discrete characters are assessed in detail: simple gap-coding, generalised gap-coding and segment-coding, a form of range-coding. The methods are applied to a data set gathered for Eucatyptus L'Hérit. informal subgenus Symphyomyrtus section Maidenana (Myrtaceae). Each method is capable of distorting relative differences between taxa, but segment-coding produces the least amount of distortion, provided the range of variation of the character is divided into a sufficient number of character states.
Continuous quantitative characters provide data for phylogenetic analysis that arc more noisy than those provided by discrete qualitative characters and should, therefore, only be used when the number of qualitative characters is insufficient for resolution of relationships. The results of such analyses should be recognised as provisional pending the discovery of more readily informative characters.     

我国23个群体体质的聚类分析与主成分分析

作者选取13项指标（头长、头宽、额最小宽、面宽、形态面高、鼻宽、鼻高、口裂宽、两眼内宽、身高、坐高、肩宽、骨盆宽）对我国23个群体体质特征进行了聚类分析与主成分分析。研究结果显示：23个群体可分为南方组、北方组（含两个小组）和中间类群组。南方组与北方组的体质区别主要为体部的长度、宽度的差异。北方组各群体之间头面部指标值差异较大,南方组各群体之间头面部指标值则较为接近。     

SHORT-TERM EVOLUTION IN THE SIZE AND SHAPE OF PEA APHIDS

Phenotypic evolution in contemporary populations can generally be witnessed only when novel selective forces produce rapid evolution. Examples of conditions that have led to rapid evolution include drastic environmental change, invasion of a new predator, or a host-range expansion. In cyclical parthenogens, however, yearly cycles of phenotypic evolution may occur due to the loss of adaptation during recombination in the sexual phase (genetic slippage), permitting an opportunity to observe adaptive evolutionary change in contemporary populations that are not necessarily subject to new patterns of natural selection. In insect herbivores, comparative studies suggest that morphological features that aid individuals in remaining on the plant or exploiting it as a food source are likely targets for selection. Here, we estimated the genetic variability of morphological traits in a cyclical parthenogen, the pea aphid (Acyrthosiphon pisum), to determine the potential for their evolution and we tested the hypothesis that size and/or shape evolves by clonal selection during one season of parthenogenetic reproduction. Genetic variation in a set of morphological traits was estimated using laboratory-reared descendents of clones collected from a single alfalfa field in May 1988 and April 1989 (henceforth, the “early” collections). In both years, there was significant clonal heritability early in the season both for overall morphology and for several individual aspects of size and shape. Because the course of short-term evolutionary change in the multivariate phenotype is a function of patterns of genetic covariance among characters, genetic correlations between size and 12 shape variables were also estimated for these early collections. A comparison between the mean phenotype of each early collection and that of a corresponding “late” collection made from the same field seven to eight clonal generations later in the same years revealed qualitatively similar changes in the average multivariate morphological phenotypes between the time periods in both years, although the difference was only significant for the 1989 samples. The pattern of genetic correlations that we estimated early in the 1989 season between overall size and various shape variables suggests that the observed short-term evolutionary changes in shape could have been due to natural selection acting only to increase overall size. We tested this hypothesis by estimating selection on size using a separate data set in which both demographic and morphological variables were measured on individuals reared under field conditions. Highly significant regressions of individual relative fitness on size were found for two major fitness components. Thus, it is likely that the evolutionary change in morphology that we observed is attributable to natural selection, possibly acting primarily through body size. A shift back to smaller size between the late 1988 and early 1989 collections from the same field suggests that either a cost of recombination or opposing selective forces during overwintering may produce persistent yearly cycles of morphological evolution in this cyclically parthenogenetic species.     

Stock structure analysis of ‘Bombay duck’ (Harpadon nehereus Hamilton, 1822) along the Indian coast using truss network morphometrics

Harpadon nehereus, commonly known as ‘Bombay duck’, is a fish with a discontinuous distribution along the Indian peninsula. The fisheries are dominant on the north‐east and north‐west coast but are absent in commercial landings below 15° north latitude. Heretofore stock assessment studies had not considered the various spawning stock components that replenish this fishery, therefore the present study. Fish samples were collected from four locations: two each from the northeast and the northwest coasts. Twenty‐four morphometric variables were measured using a box‐truss network method. Factor analysis of these variables differentiated the east and the west coast fish populations. Multiple comparisons on the factor scores indicated two independent stocks on the east coast, whereas the fishery on the west coast is replenished by a single stock. The important morphometric traits that accounted for most of the stock variations were related to swimming adaptations of the fish. Future stock assessments can consider the population on the west coast as a single stock when formulating management plans. To harvest the resource in a sustainable manner, the maritime states on the west coast should adopt collaborative efforts towards managing this fishery.     

GEOGRAPHIC PATTERNS OF VARIATION IN OFFSHORE SPOTTED DOLPHINS (STENELLA ATTENUATA) OF THE EASTERN TROPICAL PACIFIC OCEAN

The spotted dolphin (Stenella attenuata), a species commonly associated with the tuna fishery, is widely distributed in the eastern tropical Pacific Ocean (ETP). Geographic patterns in morphological characteristics of this dolphin were evaluated for 36 skull measurements of 574 museum specimens allocated to 5° latitude-longitude blocks. A strong subdivision between northern and southern offshore populations was demonstrated using principal components, canonical variates and cluster (UPGMA and function-point) analyses of block means derived from standardized, sex-adjusted measurements. Classification functions derived from a stepwise multiple discriminant analysis correctly identified more than 87 percent of the specimens as being from either a northern or southern locality. These results support recognition of southern spotted dolphins as a separate management stock. Dolphins from a sample representing a far-western locality show similarities with those from the south. Patterns of geographic variation in morphology were evaluated using Mantel tests and matrix correlations; 17 of the 36 characters showed regional patterning and 18 exhibited local patterning. Morphological trends were also assessed with respect to 14 oceanographic measures that characterize environmental variability in the ETP. In general, clinal variation in morphology mirrors a north-south trend found in several environmental variables. Overall, the most striking associations between morphological and environmental variables involved Solar Insolation (Jan.). Sea surface temperatures also exhibited a strong association with morphological variables; the highest correspondence was found between width of the temporal fossa and sea surface temperature in July. In addition, the thickness of the oxygen minimum layer exhibited a pattern of variation that was statistically associated with 58 percent of the skull characters. The geographic patterns found for cranial morphology and environmental measures are strongly clinal and in general congruent, suggesting that oceanographic conditions in part determine trends in morphological characteristics of spotted dolphins.     

Differences between the floras of the North and South Moluccas (Indonesia)

The north and south Moluccas (Indonesia) have very different geotectonic origins and, due to that, a difference in flora is to be expected. The north Moluccas moved westwards along the north coast of New Guinea to their present position, the south Moluccas moved north from Australia. On the other hand, a comparable climate in both areas and (partial) submergence during tectonic movement may have equalized both floras. Collection data from Naturalis Biodiversity Center on 1559 species in 121 families treated in Flora Malesiana were collected for the Moluccas, Sulawesi, and Western New Guinea (latitudes 9.2°S and 5.6°N and longitudes 118.8°E and 141°E) and georeferenced. Species Distribution Models (SDMs) were made, based on least correlated climate and edaphic variables, using only those species that were present in 5 or more grid cells of 5-arc minutes and models were tested for deviation from random. Both areas differ significantly and share only 50%-65% of their species. The 348 significant SDMs differ much less, though still significantly, sharing 91% of the species. Despite strong climatic and edaphic similarities between the North and South Moluccas, they differ greatly in species composition, which is in support of geotectonic reconstructions. The differences between the North and South Moluccas suggest that the continuous dispersal barriers and tectonic backgrounds have influenced their current flora.     

Allometric comparison of skulls from two closely related weasels, Mustela itatsi and M. sibirica

We conducted an interspecific comparison of skulls from two closely related but differently sized mustelid species, Mustela itatsi and M. sibirica (Mammalia, Carnivora, Mustelidae); a sexual comparison within the latter species showed remarkable size dimorphism. We clarified several differences in skull proportion related to size using allometric analyses and qualitative comparisons. Allometric analysis revealed that the skulls of male M. itatsi (the smaller species) have a relatively long palate; a slender viscerocranium and postorbital constriction; a broad, short, and low neurocranium; small carnassials; and a short mandible with a thin body and small ramus compared to the skulls of male M. sibirica (the larger species). Similar results were obtained when male M. itatsi were compared to female M. sibirica, although the male M. itatsi had a broader viscerocranium than female M. sibirica. A sexual comparison in M. sibirica revealed a larger skull size among the males with a relatively wide viscerocranium; wide postorbital constriction; a slender, long, and high neurocranium; short and wide auditory bullae; short carnassials; and a long and high mandible compared to females. Qualitative comparisons revealed changes in a few characters depending on skull size or with respect to some cranial components in each species. The interspecific differences observed were clearly larger than the intraspecific differences for three qualitative characters. The allometric and qualitative differences detected between these species suggest that each species is not simply the dwarf and/or giant morph of the other, and complicated differences were clarified.     

Identification of stock components using morphological markers

This study investigated the development of a quantitative method for distinguishing stock components of Icelandic cod Gadus morhua based on visual examination of morphology. The stock is known to be structured into genetically distinct geographic components (north and south of Iceland) and behavioural types that spawn sympatrically. Differences in morphology were tested between locations, genotypes (a proxy for behaviour) and sexes. Results show morphological markers on the head, fins and body of G. morhua that are correlated with the sex, genotype of the fish at the pantophysin (pan‐I) locus and the location at which the fish were caught. Females were found to have relatively deep bodies, and the pan‐I^BB genotype (associated with deep‐water feeding behaviour) have greater gaps between their fins. Overall, morphology is more useful for distinguishing sympatric genotypes but less powerful at identifying genetically distinct geographic sub‐populations, perhaps because counter‐gradient evolution reduces phenotypic differences even with an underlying genetic cause.     

Genetic structure,phylogeography, and demography of Anadara tuberculosa (Bivalvia) from East Pacific as revealed by mtDNA: Implications to conservation

Wild populations of the pustulose ark, Anadara tuberculosa (Bivalvia), an emblematic species of the East Pacific mangrove ecosystem declined in South American countries (Colombia, Ecuador, and Peru) mainly due to overharvesting and habitat loss or degradation. Understanding the genetic aspects of geographic variations and population structure of A. tuberculosa, currently unknown, appears as a priority to fishery authorities in order to elaborate integrated and collaborative conservation policies for fishery management, aquaculture, and stock enhancement programs. We used mtDNA sequence data to investigate haplotype diversity, genetic structure, and demography of A. tuberculosa. Results indicate genetic homogeneity of populations distributed north and south of the equator, respectively. However, statistically significant differentiation emerged between northern and southern populations with pairwise ф_ST values ranging between 0.036 and 0.092. The oceanic current system acting in the area (Panama Current and Humboldt Current) might play a role in limiting the larval dispersal of the species, still poorly understood. Demography reconstruction supported recent population expansion, possibly started after last glacial maximum. Our results would suggest separate and independent management of populations north and south of the equator.     

中国水生态足迹广度、深度评价及空间格局

运用生态足迹方法对水资源进行流量资本和存量资本区分,测算分析了中国31个省市1997—2014年的水生态足迹广度与深度。结果显示:(1)中国的水生态足迹广度受年际水资源量丰枯影响,总体呈波动趋势;各省市的水生态足迹广度存在着明显差异,南方地区水生态足迹广度普遍大于北方地区;(2)研究期内,中国的水生态足迹深度只有1998年为1,其余年份的水资源流量资本已不能满足人类生产生活的需求,需要消耗水资源存量资本;各省市之间水生态足迹深度相差较大,整体上北方高南方低,其中14个省份18年的平均水生态足迹深度为1,平均水生态足迹深度最高的地区是宁夏的308.12;(3)运用空间自相关方法对31个省市的水生态足迹广度和深度进行分析得出,中国省际水生态足迹广度与深度均存在明显的空间集聚现象。水生态足迹广度H-H集聚地区主要集中在中国南方地区,水生态足迹深度H-H集聚地区主要集中在中国北方地区。通过对全国水生态足迹广度与深度的测度分析为水生态足迹分析提供新的研究方法,同时也为区域水资源可持续利用提供理论依据。     

Maintenance of sorghum (sorghum bicolor, poaceae) landrace diversity by farmers’ selection in Ethiopia

We quantitatively examined the relationships between Sorghum landrace diversity at the field level and environmental factors and farmers’ selection practices in north Shewa and south Welo regions of Ethiopia. Surveys were conducted on 260 randomly selected farmers’ fields. The altitude and size of each field were recorded. Sorghum plants at 5 m intervals along transect lines spaced 10 m apart over each field were identified by the farmers and the owner of each field was asked why she/he decided to grow each plant. Soil samples were collected from all of the fields and analyzed for pH, organic content, and sand, silt and clay content. Simple and polynomial regressions and multiple regression analyses showed that Sorghum landrace diversity at the field level had significant relationships with the number of selection criteria used by the farmers, field altitude, field size, pH and clay content. As the number of selection criteria increased, landrace diversity in the fields increased. This relationship was not a result of the correlation between selection criteria and the environmental factors, because it was significant after statistically correcting for the effects of the environmental variables. This study quantitatively confirms the role of traditional farmers in the maintenance of sorghum landrace diversity in north Shewa and south Welo regions of Ethiopia.     

Variation in morphology of the pistillate flowers of Astrocaryum urostachys (Palmae) in Amazonian Ecuador

The variability of pistillate flower qualitative morphology and size in the palm species Astrocaryum urostachys in the Ecuadorean Amazon is analysed. In total 4393 flowers were sampled from 145 inflorescences born on 135 individual palms. Sampling was performed in 4 regions, north, western centre, southwestern centre and south. The results show that (i) qualitative morphology and relative proportions of flower parts are weakly variable, (ii) size of pistillate flowers is very variable within the total sample, within a region, within an individual palm and even within one inflorescence, (iii) no significant difference exists in flower size between the northern, western central and southwestern central regions, and (iv) there is a significant tendency to produce smaller pistillate flowers in the southern region. The low variation in qualitative morphology and in the relative proportions of pistillate flower parts within Astrocaryum urostachys provides new arguments in favour of the relevance of these characters in the taxonomy of Astrocaryum section Ayri.     

新疆胡颓子属三种植物的花粉形态及其分类学意义

该文采用主成分分析和聚类分析方法,运用扫描电镜对新疆胡颓子属(Elaeagnus Linn.)落叶组大果沙(E. moorcroftii)、尖果沙枣(E. oxycarpa)和沙枣(E. angustifolia)共计18个样品的花粉形态进行了观察和研究;全面描述了新疆胡颓子属3个种花粉的极轴长、赤道轴长、极面观、赤道面观、孔沟形态和外壁纹饰等形态特点,并对其进行数据分析,通过对聚类结果的比较,讨论不同孢粉学特征对分类结果的影响。结果表明：(1)3个种的花粉均为中等大小;萌发孔类型均为三孔沟型。(2)花粉极面观形状从三角形、钝三角形到圆三角形;赤道面观形状从菱角形、半圆形到扁圆形;外壁纹饰从皱波状到穴状。(3)以筛选出的5个反映花粉形态的主成分指标进行聚类,结果显示所选指标不能区分种;以代表花粉形态的极面观形态和赤道面观形态为指标进行聚类同样也无法区分3个种;以花粉粒大小为指标进行聚类发现,大果沙枣的花粉大小可以区别于其他2个种。研究表明除了大果沙枣花粉的大小,尖果沙枣和沙枣的花粉形态不宜直接应用于种的划分。该研究结果为新疆胡颓子属落叶组植物花粉的种间鉴定和品种划分以及进化关系的研究提供了孢粉学依据。     

Lower molar shape and size in prosimian and platyrrhine primates

The goal of this research is to evaluate the relative strength of the influences of diet, size, and phylogenetic signal on dental geometric shape. Accurate comprehension of these factors and their interaction is important for reconstructing diet and deriving characters for a cladistic analysis in fossil primates. Geometric morphometric analysis is used to identify axes of shape variation in the lower second molars of (a) prosimian primates and (b) platyrrhines. Landmarks were placed on µCT‐generated surface renderings. Landmark configurations were aligned using generalized Procrustes analysis. Principal components analysis and phylogenetic principal components analysis (pPCA) were performed on species average landmark co‐ordinates. pPCs were examined with phylogenetic generalized least squares analysis for association with size and with diet. PCs from both phylogenetic and non‐phylogenetic analyses were sufficient to separate species by broad dietary categories, including insectivores and folivores. In neither analysis was pPC1 correlated with tooth size, but some other pPCs were significantly correlated with size. The pattern of association between pPCs and size altered when centroid size and dietary variables were combined in the model; effects of diet factors typically exceeded effects of size. These results indicate a dominant phylogenetic and dietary signal in molar shape but also show some shape change correlated with size in the absence of obvious dietary associations. Geometric morphometric analysis appears to be useful for tracking functional traits in molars, particularly in tracking differences between folivorous and insectivorous species.