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Morphometric Characters (morphometric + character)
Selected AbstractsEffects of the timing of initial feeding on growth and survival of spotted mandarin fish Siniperca scherzeri larvaeJOURNAL OF FISH BIOLOGY, Issue 6 2009L. Zhang The effects of delayed first feeding on growth and survival of spotted mandarin fish Siniperca scherzeri larvae were examined under controlled conditions. Morphometric characters [yolk-sac volume, oil globule volume, head depth (HD), body depth (BD), eye diameter (ED), musculature height (MH), mouth diameter (MD) and total length (LT)], body mass (M), specific growth rate (SGR) and survival were evaluated under different first-feeding time (2, 3, 4 and 5 days after hatching). Larvae began to feed exogenously at 2 days after hatching (DAH) and the point of no return (PNR) occurred between 5 and 6 DAH at 23° C, range ±1·0° C. The yolk volume of larvae first-fed at 2 days had a significant difference compared with that of larvae first-fed at 3, 4 and 5 days on 3 and 4 DAH. The larvae first-fed at 2 days achieved comparatively better growth performance than that of 3, 4 and 5 days. On 5 DAH, all morphometric characters had significant differences between 2 and 5 days and 2 and 4 days initial feeding, respectively. Total mortality was recorded on 9 DAH for the larvae first-fed at 5 days. On 12 DAH, significant differences were observed between 2 and 4 days and 3 and 4 days initial feeding for all morphometric characters. From 16 DAH to the end of experiment, all growth variables of the larvae first-fed at 2 days were significantly higher than those in other treatments. The SGR (2,9 DAH) first-fed at 2 and 3 days were significantly higher than 4 and 5 day treatments, and the SGR (9,16 DAH) first-fed at 2 days was significantly higher than 3 and 4 day treatments. There was no significant difference, however, of SGR (16,28 DAH) among treatments. Survival rate was significantly higher at 2 days initial feeding (27·42%) when compared with 3 (15·96%) and 4 days (7·92%) initial feeding at the end of experiment. The present study suggests that the first feeding of S. scherzeri larvae should be initiated at 2 days after hatching for achieving good growth and survival. [source] Morphometric and genetic variation of small dwarf honeybees Apis andreniformis Smith, 1858 in ThailandINSECT SCIENCE, Issue 6 2007ATSALEK RATTANAWANNEE Abstract The small dwarf honey bee, Apis andreniformis, is a rare and patchily distributed Apis spp. and is one of the native Thai honey bees, yet little is known about its biodiversity. Thirty (27 Thai and 3 Malaysian) and 37 (32 Thai and 5 Malaysian) colonies of A. andreniformis were sampled for morphometric and genetic analysis, respectively. For morphometric analysis, 20 informative characters were used to determine the variation. After plotting the factor scores, A. andreniformis from across Thailand were found to belong to one group, a notion further supported by a cluster analysis generated dendrogram. However, clinal patterns in groups of bee morphometric characters were revealed by linear regression analysis. The body size of bees increases from South to North but decreases from West to East, although this may reflect altitude rather than longitude. Genetic variation was determined by sequence analysis of a 520 bp fragment of the mitochondrial cytochrome oxidase subunit b (cytb). DNA polymorphism among bees from the mainland of Thailand is lower than that from Phuket Island and Chiang Mai. Although two main different groups of bees were obtained from phylogenetic trees constructed by neighbor-joining and unweighted pair-group method using arithmetic averages programs, no clear geographic signal was present. Thus, while the minor group (B) contained all of the samples from the only island sampled (Phuket in the south), but not the southern mainland colonies, it also contained samples from the far northern inland region of Chiang Mai, other samples of which were firmly rooted in the major group (A). [source] Updating Geographic Distribution of Artemia urmiana Günther, 1890 (Branchiopoda: Anostraca) in Europe: An Integrated and Interdisciplinary ApproachINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 5 2009Theodore J. Abatzopoulos Abstract Artemia urmiana (a species previously considered endemic of Lake Urmia, NW Iran) has been found in Lake Koyashskoe, a hypersaline lake on the Black Sea coast of the Crimean peninsula (Ukraine). Therefore, this is the first record of A. urmiana in Europe which updates its distribution. The species identification was based on an integrated and interdisciplinary approach using discriminant analysis of the morphometric characters, scanning electron microscopy, and molecular profile analysis. The data derived from the above mentioned approaches converge to significant similarity of the population under investigation with A. urmiana. The updated geographic distribution of the species, deriving from the present report, asks for additional contribution of other disciplines (e.g., avian dispersal of cysts, history of salt trade) to be finally clarified. At present we suggest that the punctuated geographic distribution of A. urmiana is probably linked to its low dispersal capability, and we suppose that its presence in two distant sites could be explained by historical human salt trade between Lake Urmia and the ancient port of Kimmerik, whose remains have been found in the present Lake Koyashskoe. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Morphological and Molecular Data Reveal the Presence of the Invasive Artemia franciscana in Margherita di Savoia Salterns (Italy)INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 6 2006Graziella Mura Abstract Introduced populations of the American invasive Artemiafranciscana have been reported in Mediterranean countries except for Italy. A recent sampling at Margherita di Savoia revealed the presence of mating pairs in a saltwork known to host only parthenogens. An integrated approach, based on scanning electron microscopy of four morphological traits, discriminant analysis of 13 morphometric characters and 16S rRNA PCR-RFLP profiles of eight endonucleases was implemented for the identification of the invader. Patterns of variability in all assayed markers provided congruent and solid evidence that the allochthonous species is A. franciscana. Native parthenogens are still predominant (,98.4%) in this Italian site but they can be rapidly outcompeted by A. franciscana, as it occurred in similar cases throughout Europe and elsewhere. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] External morphology of a Slovenian population of pumpkinseed Lepomis gibbosus (L.) from a habitat with extreme thermal conditionsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2005umer Summary The external morphology and growth variability of morphometric characters of pumpkinseed (n = 141) from an oxbow (River Sava, Slovenia) that receives thermal effluent were examined using triple regression analysis. Differences in external morphology between pumpkinseed from the oxbow and both native North American (River Otonabee, Looncall Lake, Canada) and non-native Central European populations (side arms of the River Danube, Slovakia) were evaluated. Two possible morphotypes among adults were observed, whereas the morphology of juveniles appears rather uniform across geographical location (i.e. Otonabee, Looncall, Danube). This suggests that environmental conditions, i.e. epigenetical information, seem to be responsible for most of variability in pumpkinseed morphology, which represents a function of epigenetical mechanisms. However, further investigation into epigenetical interactions, especially early development, fecundity, number of spawning acts per season, parental care, egg size and age at maturation are necessary to test this hypothesis. [source] Variability of tilapias (Oreochromis spp.) introduced in Mexico: morphometric, meristic and genetic charactersJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2004I. D. L. A. Barriga-Sosa Summary In Mexico, the tilapia Oreochromis provides one of the most important sources of animal protein and income in a wide variety of communities throughout the country, however, their culture and production face severe problems because of lack of management information. Evaluated in the present study is the degree of morphological, meristic and allozyme variation of two tilapia strains, two species and one hybrid from two important reservoirs in Mexico, two tilapia fry production farms (TFPF) and an experimental production system (EPS), to diagnose the actual status and degree of variation among them. Twenty-two presumptive loci were utilized to determine the genetic variation, structuring and distances among samples. Multivariate analyses of 11 meristic and 33 morphometric characters were also evaluated, including the distance from the end of the mouth opening to the most anterior dorsal fin (0.9894), distance from the anal fin base to the anterior part of the caudal fin (0.9845) and the base length of the dorsal fin (0.9839) which contributed to the separation of groups. The canonical discriminant functions for the morphometric and meristic variables show that the correct classification of the organisms in percentages and in the sites of origin was on average 72%. The tilapia from the reservoirs and the experimental production system had higher genetic variations than tilapia from the fry production farms (average He 0.310, 0.062, 0.151 for Metztitlan, Infiernillo and EPS, respectively, vs 0.024 and 0.000 for Los Amates and Zacatepec, respectively). The genetic data indicate that fishes of the TFPF should be monitored closely, as they are the main source of dispersion to the reservoirs. Present results show that these data could be a fast and reliable aid to the fisheries and management of tilapia in Mexico. [source] Effects of the timing of initial feeding on growth and survival of spotted mandarin fish Siniperca scherzeri larvaeJOURNAL OF FISH BIOLOGY, Issue 6 2009L. Zhang The effects of delayed first feeding on growth and survival of spotted mandarin fish Siniperca scherzeri larvae were examined under controlled conditions. Morphometric characters [yolk-sac volume, oil globule volume, head depth (HD), body depth (BD), eye diameter (ED), musculature height (MH), mouth diameter (MD) and total length (LT)], body mass (M), specific growth rate (SGR) and survival were evaluated under different first-feeding time (2, 3, 4 and 5 days after hatching). Larvae began to feed exogenously at 2 days after hatching (DAH) and the point of no return (PNR) occurred between 5 and 6 DAH at 23° C, range ±1·0° C. The yolk volume of larvae first-fed at 2 days had a significant difference compared with that of larvae first-fed at 3, 4 and 5 days on 3 and 4 DAH. The larvae first-fed at 2 days achieved comparatively better growth performance than that of 3, 4 and 5 days. On 5 DAH, all morphometric characters had significant differences between 2 and 5 days and 2 and 4 days initial feeding, respectively. Total mortality was recorded on 9 DAH for the larvae first-fed at 5 days. On 12 DAH, significant differences were observed between 2 and 4 days and 3 and 4 days initial feeding for all morphometric characters. From 16 DAH to the end of experiment, all growth variables of the larvae first-fed at 2 days were significantly higher than those in other treatments. The SGR (2,9 DAH) first-fed at 2 and 3 days were significantly higher than 4 and 5 day treatments, and the SGR (9,16 DAH) first-fed at 2 days was significantly higher than 3 and 4 day treatments. There was no significant difference, however, of SGR (16,28 DAH) among treatments. Survival rate was significantly higher at 2 days initial feeding (27·42%) when compared with 3 (15·96%) and 4 days (7·92%) initial feeding at the end of experiment. The present study suggests that the first feeding of S. scherzeri larvae should be initiated at 2 days after hatching for achieving good growth and survival. [source] Description and ontogeny of young Stolephorus baganensis and Thryssa kammalensis, two Engraulididae from Peninsular MalaysiaJOURNAL OF FISH BIOLOGY, Issue 6 2000V. Sarpéadonti The morphology of the digestive system was useful to distinguish the larvae of Stolephorus baganensis and Thryssa kammalensis before the full development of their dorsal and anal fins. The relative positions of these fins, the length of the anal fin, and body depth, were good criteria for identifying individuals >10·0 mm LS. For both species, the relative growth of the ten morphometric characters studied was best explained by linear piecewise regressions indicating inflection in allometry at specific standard lengths. Most of these sudden changes in growth rate occurred between 6·9 and 10·0 mm LS for S. baganensis and between 5·8 and 8·9 mm LS for T. kammalensis. Double-centred principal component analysis (PCA) confirmed important changes in the external morphology of both species during this transition period. Prior to this period, the main parameters characterizing the global morphological changes of both species were the length and position of dorsal and anal fins whereas they were body depth and eye diameter (only in S. baganensis) for larger specimens. Complete development of scales did not appear as a suitable criterion to define the end of the larval period, which, instead, was set at the size at which larvae presented an adult-like pigmentation (respectively 35·0 mm LS and 55·0 mm LS in S. baganensis and T. kammalensis). [source] PRELIMINARY ANALYSIS OF QUANTITATIVE GENETICS AND PHENOTYPIC PLASTICITY IN AULACOSEIRA SUBARCTICA (BACILLAR-IOPHYTA)JOURNAL OF PHYCOLOGY, Issue 2000S. M. Edgar Several clones of Aulacoseira subarctica were isolated from Yellowstone, Lewis, and East Rosebud Lakes (Montana, Wyoming). Two to four clones from each lake were grown in batch cultures under three light intensities, 2, 11.4 and 115 ,E m,2 s,1. Clones were conditioned to their light environment for a three-week period. Inoculants from the conditioned clones taken during log phase of growth, were grown until in log phase, then samples were collected. Five randomly chosen valves for 2 replicates of each clone were examined using a scanning electron microscope and captured on film at a magnification of 20,000x. Each image was digitized and quantitative morphometric characters were measured. A preliminary quantitative genetic analysis was performed on selected characters within each light environment. Plasticity of characters within clones across the three light regimes were also examined. The amount of variability found within characters in A. subarctica will be discussed in terms of environmental, genetic, and microenvironmental sources. [source] Geography of morphological differentiation in Asellus aquaticus (Crustacea: Isopoda: Asellidae)JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 2 2009S. Prevor Abstract We implemented a detailed morphometry and multivariate statistics to establish a general, large-scale racial differentiation in Asellus aquaticus (L.) sensu Racovitza. We ascertained that in surface populations a set of 11 morphometric characters might equivalently be represented by the pleopod respiratory area size alone. The analyses resulted in a distinct distribution pattern, with the large respiratory area populations disposed mainly along the Dinaric karst between southern Slovenia and western Macedonia and surrounded by the medium respiratory area morph, spatially irregularly substituted by the small area morph. This pattern is in contradiction with the distribution pattern of molecularly defined clades (as shown by Verovnik et al. 2005). We could find no ecological, hydrographical or paleogeographical explanations for such distribution pattern either. The only hypothetical explanation would be a preservation of the large respiratory area as a plesiomorphic character in the comparatively sheltered karst habitats, while throughout the easier accessible parts of the species range it was replaced by the ,modern' smaller area size. While a diminution of the respiratory area functionally means an increased sclerotization , hardening of pleopod IV,V exopodites, endopodites of pleopods III,V remain less sclerotized, probably respiratory and osmoregulatory functional. Zusammenfassung Die globale Rassendifferenzierung von Asellus aquaticus (L.) sensu Racovitza wurde anhand eingehender Morphometrie und multivariater Statistik untersucht. Es stellte sich heraus, dass der gesamte Satz von 11 morphometrischen Merkmalen allein durch das Merkmal ,Flächengröße der Pleopoden-Respirationsfläche' ersetzt werden kann. Die Analysen ergaben ein deutliches Muster, in dem Populationen mit großen Respirationsflächen überwiegend im Dinarischen Karst zwischen Süd-Slowenien und West-Makedonien verbreitet sind, von Morphen mit mittelgroßen Respirationsflächen umgeben werden, welche wiederum räumlich zerstreut von Morphen mit kleinen Respirationsflächen ersetzt werden. Dieses Muster widerspricht der Verbreitung von molekular-systematisch ermittelten Gruppen (Verovnik et al. 2005). Wir konnten keine ökologische, hydrographische oder paläogeographische Erklärung dafür finden. Die einzige hypothetische Erklärung könnte eine Erhaltung der großen Respirationsflächen als eines plesiomorphen Merkmals in vergleichsweise isolierten Karstgebieten sein, während sie in leichter besiedelbaren Gebieten von den ,modernen' kleineren Respirationsflächen ersetzt wurden. Es muss betont werden, dass eine Verkleinerung der Respirations-Area mit der Sklerotisierung der Exopoditen an den Pleopoden IV-V verbunden ist, während die Endopoditen der Pleopoden III-V ihre geringe Sklerotisierung beibehalten und somit wahrscheinlich atmungs- und osmoregulatorisch aktiv bleiben. [source] Evolutionary assessment of Artemia tibetiana (Crustacea, Anostraca) based on morphometry and 16S rRNA RFLP analysisJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 3 2005A. D. Baxevanis Abstract Over the last few years, molecular-based assays in the genus Artemia have considerably enriched prior systematic assessments based on morphometry. For the first time, morphometric and 16S rRNA PCR-RFLP analyses on all type-locality bisexual species of the genus have been employed here. Emphasis was put on the Asian species (Artemia urmiana, A. tibetiana, A. sinica) where patterns of divergence and reproductive isolation are rather discrete, and especially on A. tibetiana for which recent reports have questioned its specific status. Discriminant analysis of morphometric characters has shown significant differentiation among species. Classification scores were 99.4 and 100% for males and females, respectively. Mitochondrial DNA RFLP patterns have given indications for lower, albeit similar patterns of differentiation compared with those obtained by morphometry. Artemia tibetiana and A. urmiana are mitochondrially indistinguishable which is suggestive of recent ancestry. Our data, in conjunction with past evidence, are supportive of a significant amount of divergence between A. tibetiana and A. sinica. Morphometric and molecular assays can be reciprocally informative provided theory and patterns of speciation are incorporated into systematic assessments. Résumé Ces dernières années, les outils moléculaires utilisés dans l'étude du genre Artemia ont considèrablement enrichi les analyses systématiques antérieures basées sur la morphométrie. Pour la première fois, des analyses morphométriques et des analyses PCR-RFLP de l'ARN ribosomique 16S ont été effectuées pour toutes les espèces amphigoniques d'Artemia venant des localités types. Dans cette étude, nous nous sommes concentrés sur les espèces asiatiques (A. urmiana, A. tibetiana, A. sinica), qui présentent des traits de divergence et un isolement reproductif assez singuliers, et tout particulièrement sur l'A. tibetiana dont le statut d'espèce à part entière a été mis en doute dans de récentes études. Une analyse discriminante des caractéristiques morphométriques a révélé une différenciation importante parmi les espèces. Pour les mâles et les femelles, les scores de classification étaient respectivement de 99,4% et 100%. Les profils RFLP de l'ADN mitochondrial ont montré une différenciation similaire à celle observée grâce à l'analyse morphométrique. L'ADN mitochondrial de l'A. tibetiana est indifférenciable de celui de l'A. urmiana, ce qui suggère que ces deux espèces ont récemment divergé. Nos données, combinées à celles recueillies par le passé, indiquent une grande divergence entre l'A. tibetiana et l'A. sinica. Les analyses morphométriques et moléculaires peuvent se compléter à condition de tenir compte de la théorie de la spéciation et des modèles de spéciation durant les analyses systématiques. [source] The Ordovician Trilobite Carolinites, A Test Case for Microevolution in A Macrofossil LineagePALAEONTOLOGY, Issue 2 2002Tim McCormick We use geometric morphometrics to test a claim that the Ordovician trilobite Carolinites exhibits gradualistic evolution. We follow a previously proposed definition of gradualism, and define the criteria an ideal microevolutionary case study should satisfy. We consider the Lower,Middle Ordovician succession at Ibex, western Utah to meet these criteria. We discovered examples of: (1) morphometric characters which fluctuate with little or no net change; (2) characters which show abrupt ,step' change; (3) characters which show transitional change through intermediate states. Examples belonging to (2) and (3) exhibit reversals. The transitional characters were tested against a null hypothesis of symmetrical random walk. The tests indicated that they were not changing under sustained directional selection. Two alternative interpretations are possible. (1) The characters are responding to random causes (genetic drift or rapidly fluctuating selection pressures) or to causes that interact in so complex a way that they appear random. This observation may be applicable to most claimed cases of gradualistic evolution in the literature. (2) Sampling was at too poor a resolution to allow meaningful testing against the random walk. If so, then this situation is likely to apply in most evolutionary case studies involving Palaeozoic macrofossils. [source] Systematics and evolutionary relationships of the mountain lizard Liolaemus monticola (Liolaemini): how morphological and molecular evidence contributes to reveal hidden species diversityBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2009FERNANDO TORRES-PÉREZ The delimitation of species is a major issue in systematic biology and has been a re-emerging discipline in the last decade. A number of studies have shown that the use of multiple data sets is critical for the identification of cryptic species, particularly in groups with complex evolutionary histories. Liolaemus monticola is a montane lizard species distributed in central Chile (32°,42°S), with four described subspecies in a latitudinal gradient from north to south: L. m. monticola, L. m. chillanensis, L. monticola ssp. and L. m. villaricensis. In order to test the systematic status and phylogenetic relationships of the taxa included in the L. monticola group, we analysed morphological (morphometric and meristic) and molecular (allozyme and mitochondrial DNA) data sets. The results of the morphological analyses showed that meristic variables correctly assigned individuals with higher accuracy than did morphometric characters. The results of the analyses of allozyme data revealed eight diagnostic loci that are evidence for significant differences among the four L. monticola subspecies. Phylogenetic analyses with mitochondrial DNA data, including additional species, showed that the L. monticola group is polyphyletic. We postulate that the four current subspecies represent independent evolutionary lineages and must be raised to the specific level as L. monticola, L. chillanensis and L. villaricensis. The taxonomic status of the unnamed L. monticola ssp. remains unresolved, although we provide a preliminary proposal. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 635,650. [source] | |||||||||||||