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Morphometric Differentiation (morphometric + differentiation)
Selected AbstractsMorphometric differentiation between populations of Papaver radicatum (Papaveraceae) in northern ScandinaviaBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2000EVA SELIN The pattern of morphological variation was investigated in isolated northern Scandinavian populations of Papaucr radicatum, a perennial species with a disjunct distribution in the Scandinavian mountain range, Iceland and the Farces. Canonical variates analysis and Ward's clustering were applied to data sets from wild-collected seed and capsule material, and from cultivated leaf mated from seven populations of P. radicatum in northern Scandinavia, usually assigned to the sspp. subglobosum, hyperboreum and macrostigma. Automatized image acquisition and shape description techniques were used to describe variation in seed shape. The present study supports the multivariate analyses obtained with the southern Norwegian P. radicatum populations in that some of the assumed subspecies show inter-population variation and are not well delimited. In the analyses of capsule and seed morphology as well as leaf morphology, the populations of the sspp. hyperboreum and macrostigma are grouped together. Previous studies of chromosomal and morphological variation in southern Norwegian P. radicatum suggested that the degree of interracial differentiation was similar between all races regardless of their degree of geographic separation. The pattern of differentiation has been taken as a support of in Situ refugial survival during the Weichselian glaciation. As in similar multivariate analyses of southem Norwegian P. radicatum, the multivariate analyses of northern Scandinavian P. radicatum do not confirm such a scenario. The results rather point to the possibility that populations from the sspp. hyperboreum and macrostigna complex were separated during the post-glacial hypsithemal. The morphologically distinct ssp. subglobosum could have been isolated at an earlier stage. [source] Genetic and morphometric differentiation among island populations of two Norops lizards (Reptilia: Sauria: Polychrotidae) on independently colonized islands of the Islas de Bahia (Honduras)JOURNAL OF BIOGEOGRAPHY, Issue 7 2007C. F. C. Klütsch Abstract Aim, Anole lizards (Reptilia: Sauria: Polychrotidae) display remarkable morphological and genetic differentiation between island populations. Morphological differences between islands are probably due to both adaptive (e.g. differential resource exploitation and intra- or interspecific competition) and non-adaptive differentiation in allopatry. Anoles are well known for their extreme diversity and rapid adaptive speciation on islands. The main aim of this study was to use tests of morphological and genetic differentiation to investigate the population structure and colonization history of islands of the Islas de Bahia, off the coast of Honduras. Location, Five populations of Norops bicaorum and Norops lemurinus were sampled, four from islands of the Islas de Bahia and one from the mainland of Honduras. Methods, Body size and weight differentiation were measured in order to test for significant differences between sexes and populations. In addition, individuals were genotyped using the amplified fragment length polymorphism technique. Bayesian model-based and assignment/exclusion methods were used to study genetic differentiation between island and mainland populations and to test colonization hypotheses. Results, Assignment tests suggested migration from the mainland to the Cayos Cochinos, and from there independently to both Utila and Roatán, whereas migration between Utila and Roatán was lacking. Migration from the mainland to Utila was inferred, but was much less frequent. Morphologically, individuals from Utila appeared to be significantly different in comparison with all other localities. Significant differentiation between males of Roatán and the mainland was found in body size, whereas no significant difference was detected between the mainland and the Cayos Cochinos. Main conclusions, Significant genetic and morphological differentiation was found among populations. A stepping-stone model for colonization, in combination with an independent migration to Utila and Roatán, was suggested by assignment tests and was compatible with the observed morphological differentiation. [source] Further evidence and characterization of Artemia franciscana (Kellogg, 1906) populations in ArgentinaJOURNAL OF BIOGEOGRAPHY, Issue 11 2004Francisco Amat Abstract Aim, This paper reports the presence of Artemia franciscana (Kellogg, 1906) in Mar Chiquita (CHI) salt lake and in Las Tunas (TUN) lagoon, as well as at a shallow lake in Salinas Grandes (Province of Córdoba) in Argentina. To date, this species has been considered absent from Argentina. This study also provides further data on the characterization of the A. franciscana populations from this area. Location, Province of Córdoba (Argentina). Methods, The cyst samples collected at the three hypersaline environments were measured to assess its mean diameter with a dissecting microscope. The length of the nauplii hatched from the cysts was also determined with the microscope. The adults raised from these nauplii under strictly controlled conditions were analysed for 12 morphological parameters and compared through multivariate discriminant analysis with other American populations. Fatty acids from the total lipids were analysed by gas chromatography. Reproductive compatibility was evaluated from single-pair intraspecific and interspecific crosses of adult specimens. Results, The results endorse the morphometric assimilation of the Artemia populations of this area to other American populations of the A. franciscana,super-species', together with its morphometric differentiation from the species A. persimilis (Piccinelli & Prosdocimi, 1968). The more conspicuous population from CHI shows cross-fertility with A. franciscana original from San Francisco Bay (California, USA). Both populations from CHI and TUN show cross-fertility between them and reproductive isolation with A. persimilis from Hidalgo (Province of La Pampa), which to date is considered to be endemic or exclusive of hypersaline ecosystems in Argentina. The reproductive characteristics displayed by the population from TUN lagoon suggest the existence of an occasional hybridization between A. franciscana and A. persimilis (Papeschi et al., 2000). Artemia cysts from CHI and TUN show a fatty acid profile rich in eicosapentaenoic acid differing markedly from the fatty acid profiles found in A. persimilis cysts. Main conclusions:,Artemia franciscana is present in Argentina at 36° S and north of this latitude. Artemia persimilis is confined to the south of latitude 37°10, S. There are different pieces of evidence that point to a certain level of hybridization of the two species taking place in the land belt between these parallels. [source] Genetic and morphological differentiation in Tephritis bardanae (Diptera: Tephritidae): evidence for host-race formationJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2004T. Diegisser Abstract The fruit fly Tephritis bardanae infests flower heads of two burdock hosts, Arctium tomentosum and A. minus. Observations suggest host-associated mating and behavioural differences at oviposition indicating host-race status. Previously, flies from each host plant were found to differ slightly in allozyme allele frequencies, but these differences could as well be explained by geographical separation of host plants. In the present study, we explicitly test whether genetic and morphological variance among T. bardanae are explained best by host-plant association or by geographical location, and if this pattern is stable over a 10-year period. Populations of A. tomentosum flies differed significantly from those of A. minus flies in (i) allozyme allele frequencies at the loci Pep-A and Pgd, (ii) mtDNA haplotype frequencies and (iii) wing size. In contrast, geographical location had no significant influence on the variance estimates. While it remains uncertain whether morphometric differentiation reflects genotypic variability or phenotypic plasticity, allozyme and mtDNA differentiation is genetically determined. This provides strong evidence for host-race formation in T. bardanae. However, the levels of differentiation are relatively low indicating that the system is in an early stage of divergence. This might be due to a lack of time (i.e. the host shift occurred recently) or due to relatively high gene flow preventing much differentiation at loci not experiencing selection. [source] From oviparity to viviparity: a preliminary note on the morphometric differentiation between oviparous and viviparous species assigned to the genus Liolaemus (Reptilia, Squamata, Liolaemidae)JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 3 2003J. M. Cei Abstract Embryonic growth requires a considerable internal space in viviparous female lizards and this need for space should be reflected in their external morphometry. External morphological differences associated with the reproductive mode in 12 viviparous and 18 oviparous species of Liolaemus lizards were identified. Size differences between viviparous and oviparous species were elucidated by axilla-groin/snout-vent relationship. Axilla-groin distance, considered a size estimator of visceral cavity, surpassed 50% of snout-vent length in viviparous females, while it is always less than 50% in oviparous females. This difference between the two reproductive modes is statistically significant. Zusammenfassung Das Embryonenwachstum beansprucht in viviparen Eidechsenweibchen einen beachtlichen internen Raum und dieser Anspruch auf Raum sollte sich in ihrer externen Morphometrie wiederfinden. Es wurden externe morphologische Unterschiede, die mit dem Reproduktionsmodus in Zusammenhang stehen in 12 viviparen und 18 oviparen Arten von Eidechsen der Gattung Liolaemus erfaßt. Größenunterschiede zwischen viviparen und oviparen Arten wurden durch das Verhältnis der Längen Achselhöhle-Leiste zu Maul-Kloake entdeckt. Die Achselhöhle-Leisten Distanz, ein Wert, der als Maß des Bauchraums angesehen werden kann, überschritt 50 % der Maul-Kloaken-Länge bei den viviparen Weibchen, während sie bei den oviparen Weibchen stets unter 50% war. Dieser Unterschied zwischen den beiden Forpflanzungsweisen ist statistisch signifikant. [source] | ||||||||||