Patterns Of Morphological Variation Research Articles

Character selection by path and principal analysis for enhanced seed size and yield in local castor bean (Ricinus communis L.)

Castor bean (Ricinus communis L.) is a commercial plant that widely uses in industry and manufacture. The aim of this study is to study the selection of seed size characteristics to increase yields and determine accessions that have a high yield. Twenty-two local castor accessions with two replications were conducted at Malang in 2017. Path analysis was done on 21 characters. The result showed that the seed diameter had a high positive direct effect on seed volume. The character that had a high direct effect on seed weight per plant is weight of inflorescence per plant. Seed diameter had a high positive direct effect on 100-seed weight. In order to identify the patterns of morphological variation, PCA was conducted. In this study, the three first components (PC1, PC2, and PC3) were contributed to 86.42% of the total variation. PC1 was strongly correlated with capsule length, capsule diameter, seed length, seed width, seed thickness, seed diameter, inflorescence length, and seed volume. PC2 varied as a measure of the days to flowering, days to harvesting, plant height, length of main stem, node number in main stem, cluster number. PC3 showed varied as inflorescence weight per plant, seed number per plant, inflorescence number per plant, capsule number per plant, seed weight per plant. The dendrograms obtained using the agglomerative hierarchical clustering generated three main clusters. The accessions that had higher sum of ranking in each cluster in each seed character contributed in first principal component were ASB60, ASB81, ASB22, LMG0216U1, SUKO0316, SUKO0216, LMG0516, TBN0316, TBN0816, LMG0216U2, and TBN1016.

Morphological disparity in theropod jaws: comparing discrete characters and geometric morphometrics

AbstractDisparity, the diversity of form and function of organisms, can be assessed from cladistic or phenetic characters, and from discrete characters or continuous characters such as landmarks, outlines, or ratios. But do these different methods of assessing disparity provide comparable results? Here we provide evidence that all metrics correlate significantly with each other and capture similar patterns of morphological variation. We compare three methods of capturing morphological disparity (discrete characters, geometric morphometric outlines and geometric morphometric landmarks) in coelurosaurian dinosaurs. We standardize our study by focusing all our metrics on the mandible, so avoiding the risk of confounding disparity methods with anatomical coverage of the taxa. The correlation is strongest between the two geometric morphometric methods, and weaker between the morphometric methods and the discrete characters. By using phylogenetic simulations of discrete character and geometric morphometric data sets, we show that the strength of these correlations is significantly greater than expected from the evolution of random data under Brownian motion. All disparity metrics confirm that Maniraptoriformes had the highest disparity of all coelurosaurians, and omnivores and herbivores had higher disparity than carnivores.

Patterns of morphological variation in the Schlegel\u2019s Japanese gecko (Gekko japonicus) across populations in China, Japan, and Korea

BackgroundStudies of morphological variation within and among populations provide an opportunity to understand local adaptation and potential patterns of gene flow. To study the evolutionary divergence patterns of Schlegel’s Japanese gecko (Gekko japonicus) across its distribution, we analyzed data for 15 morphological characters of 324 individuals across 11 populations (2 in China, 4 in Japan, and 5 in Korea).ResultsAmong-population morphological variation was smaller than within-population variation, which was primarily explained by variation in axilla-groin length, number of infralabials, number of scansors on toe IV, and head-related variables such as head height and width. The population discrimination power was 32.4% and in cluster analysis, populations from the three countries tended to intermix in two major groups.ConclusionOur results indicate that morphological differentiation among the studied populations is scarce, suggesting short history for some populations after their establishment, frequent migration of individuals among the populations, and/or local morphological differentiation in similar urban habitats. Nevertheless, we detected interesting phenetic patterns that may predict consistent linkage of particular populations that are independent of national borders. Additional sampling across the range and inclusion of genetic data could give further clue for the historical relationship among Chinese, Japanese, and Korean populations of G. japonicus.

Morphological variation pattern of Aquilegia ecalcarata and its relatives

AbstractAquilegia ecalcarata Maxim. is the only spurless species within the genus Aquilegia and comprises a monophyletic clade with A. yabeana Kitag., A. kansuensis Brühl, and A. rockii Munz. Our previous study on the genetic diversity of those four species revealed that the populations of A. ecalcarata can be divided into two groups, indicating possible genetic difference within A. ecalcarata. However, it is not clear whether the genetic difference is related to the morphological variation among species and groups of A. ecalcarata populations. To answer that question, the morphological variation patterns based on 22 floral and 19 vegetative traits from 42 populations, covering the entire distribution of A. ecalcarata and its relatives, were analyzed in the present study. The result showed that: (i) the differences among the four species were reflected in the floral rather than the vegetative traits; (ii) populations of A. yabeana and A. rockii fell into one cluster each, and each of the six clusters occupied its own distribution range; (iii) one of two A. ecalcarata clusters fell into a subgroup and shared common floral traits with A. rockii; (iv) the individuals of A. ecalcarata form. ecalcarata and form. semicalcarata were often mixed in the same population; and (v) the populations of A. kansuensis were split into two clusters, which differed obviously in floral traits. These results will provide an important morphological basis for the redefinition of species and lay a foundation for the further exploration of the “spurless” A. ecalcarata.

Genetic and Morphological Diversity in Aphis gossypii Glover (Hemiptera: Aphididae) in the Pacific Basin

Aphis gossypii Glover is cosmopolitan pest aphid, known to be represented by host-associated lineages. Although it is widespread in the Pacific Basin, there has been no assessment of this species in this region. We examined patterns of morphological variation within and among populations collected across hosts and islands using multivariate morphometric analyses. Genetic variation was determined using microsatellite flanking region sequences and mitochondrial cytochrome oxidase subunit 1. This study confirmed the existence of genetically distinct host-associated lineages. We found that host plant affects morphological expression and therefore morphological criteria cannot be used to identify lineages. Comments are provided on the origin and maintenance of these host lineages and implications for management of this important pest aphid species.

Digest: Colonizing rodents overcome ecological incumbency in an island system*

Do primary radiations inhibit the persistence and diversification of secondary colonizers? Rowsey etal. test predictions of this "incumbency effect" by contrasting patterns of morphological variation in two murine rodent clades on the Philippine island of Luzon. They find that in this system, primary colonizers may impose constraints via biotic filtering, and may also restrict size evolution in secondary colonists.

Morphological discontinuous variation and disparity in Lutzomyia (Tricholateralis) cruciata Coquillett, 1907 are not related to contrasting environmental factors in two biogeographical provinces

Lutzomyia cruciata (Diptera: Phlebotominae) is an important Leishmania vector with wide distribution in America. However, geographical patterns of morphological variation of populations along its longitudinal and latitudinal distribution are still unknown. In this work, we quantified morphological variation and disparity in 243 specimens (females) from nine sample groups of Lu. cruciata from two biogeographical provinces in Mexico: Veracruzan Province (five groups) and Yucatan Peninsula Province (four groups). We registered two linear morphometric data of a reproductive structure (spermatheca) and one landmark configuration for wing shape. Our questions were if intraspecific morphological variation and disparity are related to contrasting environmental factors in these two provinces. First, our results from canonical variates analyses of the spermatheca and wing shape revealed more differences among groups of specimens within a biogeographic province than between. Second, our regression analyses revealed that morphometric variation is weakly related to 20 environmental variables considered for the two biogeographic provinces. Levels of morphological disparity in the spermatheca and wing shape within the two provinces are the same regardless of environmental homogeneity in the Yucatan Province or heterogeneity in the Veracruzan Province. These patterns of morphological variation and disparity weakly correlated with environmental variables suggest that intraspecific variation in Lu. cruciata is not clinal within a province. Subsequent investigations will be required to elucidate suspected correlations of local discontinuous phenotypes with genetic divergence within a biogeographical province.

Patterns of morphological divergence in fruit fly: response to nutritional variations through changes in allometric relationships and trait sizes

AbstractThe morphological structures of organisms may be subject to divergence when exposed to varied nutritive conditions, due to the occurrence of developmental plasticity and its fixation due to the process of genetic accommodation. The allometric relationship of traits with respect to each other and to the whole body defines the shape of an individual. Developmental plasticity in different nutritional regimes affects the absolute value of traits and its relative scaling with respect to body size. We investigated the diversification in wing dimensions and body size in Drosophila ananassae by utilizing isofemale lines of Bilaspur and karyotypically characterized stocks of Varanasi, by rearing flies in nutritional regimes having differences in protein and carbohydrate compositions. The effect of dietary protein variations on plasticity of absolute size of body and wing dimensions was found to be highly genotype‐dependent as compared to sucrose, in both the sexes and in both the populations. This suggests that variation in proteins in natural environment may induce greater selective pressure on traits and may lead to diversification in morphological structures due to the process of genetic accommodation. We found highly significant genetic variation in plasticity for allometric relationship in Bilaspur population for variations in protein as well as carbohydrate in dietary media. However, constraints in plasticity of allometric slopes for wing dimensions in karyotypic stocks of Varanasi were found in response to both the nutritional variations. The analysis of reaction norms also suggested that there is involvement of alpha inversion present in 2L chromosome of Varanasi population, in adapting to different nutritional environmental conditions due to changes in static allometry of different wing dimensions. Overall, this study reveals that the nutritional ecology and evolutionary allometry govern the morphological divergence of traits size and shape in a genotypic‐dependent manner, thereby resulting in morphological evolutions.

Exploratory study of the three-dimensional morphological variation of the jaw associated to teeth loss

PurposeThe aim of this study is to evaluate the morphological variability in mandibles with different types of edentulism, comparing the use of traditional morphometrics and tridimensional geometric morphometrics. MethodsTraditional morphometrics and geometric morphometrics (GM) exploratory analysis, by principal components (PCs) and PC scores, were performed on a sample of 24 cadaveric hemi mandibles. A digital reconstruction of 3D surfaces of each specimen was obtained by CT scans segmentation. The mandibles were divided in three groups: full dentition (G1), partial edentition (G2) and total edentition (G3). The results of the two methods were compared in relation to the morphological variability determined with each method. ResultsBoth methods were consistent in terms of morphological variability between the defined groups. The main shape variations observed were a decrease in mandibular body height, a widening of the cross sectional morphology on the symphysis, a shorten-narrowed Ramus and a deeper sigmoid notch, in the partially or totally edentition groups, compared to the full dentition group. DiscussionThe general patterns of morphological variations associated with edentulism that have been reported in literature could be visualized with GM method, which had not been previously used for this purpose. The GM methods could offer a more detailed definition of shape variations, which is critical in a clinical context. Moreover, GM allowed defining configurations of mean morphologies and an image library with different types of morphological variations.

Scale-dependent patterns of intraspecific trait variations in two globally invasive species.

Animal species often show substantial intraspecific trait variability (ITV), yet evidence for its flexibility across multiple ecological scales remains poorly explored. Gaining this knowledge is essential to better understand the different processes maintaining ITV in nature. Due to their broad geographic ranges, widespread invasive species are expected to display strong phenotypic variations across their distribution. Here, we quantified the scale-dependent patterns of morphological variability among invasive populations of two global freshwater invaders-red swamp crayfish Procambarus clarkii and pumpkinseed sunfish Lepomis gibbosus-both established in American and European lakes. We quantified patterns in body morphology across different ecological (Individual and Population) and spatial scales (Region). We then analyzed the scale-dependency of morphological variations among lake populations that span a diversity of abiotic and biotic conditions. Next, we used stable isotope analyses to test the existence of ecomorphological patterns linking morphology and trophic niche of individuals. We found that trait variations mainly accounted for at the regional and individual levels. We showed that populations of both species strongly differed between United States and Europe whereas habitat characteristics had a relatively minor influence on morphological variations. Stable isotope analyses also revealed that ecomorphological pattern for the trophic position of L. gibbosus was region-dependent, whereas no ecomorphological patterns were observed for P. clarkii. Overall, our study strongly supports the notion that the patterns of phenotypic variability among invasive populations are likely to modulate the ecological impacts of invasive species on recipient ecosystems.

<em>Puercolestes</em> and <em>Betonnia</em> (Cimolestidae, Mammalia) from the early Paleocene (Puercan 3 Interval Zone) of northeastern Montana, U.S.A.

In northeastern Montana, fossil localities in the Garbani Channel Complex and other early Paleocene (Puercan 3 Interval Zone) localities are preserved in the Tullock Member of the Fort Union Formation. They document an early phase in the recovery of the terrestrial fauna of the North American Western Interior after the mass extinction marking the Cretaceous-Paleogene (K-Pg) boundary. The cimolestids Puercolestes simpsoni and Betonnia tsosia were typified on fragmentary jaws and isolated teeth found in Puercan 2 and 3 Interval Zones (Pu2, Pu3) in the Nacimiento Formation, San Juan Basin, New Mexico. The available samples of these genera from both New Mexico and Montana are small and dominantly consist of isolated teeth. Characters of upper cheek teeth, P4 and M1–M3, justify provisional recognition of Puercolestes sp. cf. Pu. simpsoni and the somewhat smaller Betonnia sp. cf. Be. tsosia in Pu3 local faunas in the Tullock Member. In contrast, discovery of characters distinguishing the isolated lower cheek teeth, p4s and m1–m3s, of these species must await recovery of dentulous dentaries documenting the patterns of morphological variation of their lower dentitions. Fossils from the Tullock Member add support to the current interpretation that cimolestids were taxonomically diverse and geographically widespread but relatively rare members of the faunas of the North American Western Interior during approximately the first million years of the Paleocene.

Morphological variability patterns in the Balearites-Pseudothurmannia genera boundary (Ammonoidea, late Hauterivian): taxonomic and biostratigraphic implications

As for many other ammonoid groups, the Hauterivian family Crioceratitidae has been traditionally approached from a strictly typological viewpoint, leading to considerable taxonomic oversplitting. Balearites angulicostatus (d’Orbigny, 1841) and Pseudothurmannia ohmi (Winkler, 1868) are two successive species within this lineage, which are used as index species in biostratigraphy. In order to clarify the taxonomic position of the two aforementioned species, the present study carries out morphometric analyses on 111 stratigraphically controlled specimens from the Arroyo Gilico section (SE Iberian Peninsula), enabling us to conclude that the diagnoses of both species should be broadened to encompass the continuous morphological variations occurring within their populations. A phenotypic variability model among eight extreme poles is described for B. angulicostatus, whereas P. ohmi ranges between two extreme poles. The detailed study of shell morphology through time recognizes the evolutionary changes between the two species: anagenetic processes such as the increase of whorl height growth rate and tachymorphosis of ontogenetic stages, coupled with punctuated changes such as the loss of heteromorphic coiling and an allometric hypermorphosis. Some of these may be inherent to the variation of the species themselves, but others such as the loss of heteromorphism seem to be related to palaeoenvironmental factors such as changes in nutrient supply to the sea.

Variación morfológica altitudinal entre poblaciones de Pinus devoniana lindl. y la Variedad putatiVa cornuta martínez en micHoacÁn


 
 
 La comprensión de los patrones de variación morfológica a lo largo de gradientes altitudinales es útil para distinguir entidades taxonómicas y tomar decisiones de manejo. conos, semillas, fascículos y yemas fueron analizados en individuos de 16 poblaciones naturales de Pinus devoniana (ex P. michoacana). el material se recolectó a lo largo de un transecto de 1,600 a 2,450 msnm, a razón de una población cada 50 m, cerca de la ciudad de morelia, en el estado de michoacán. se realizaron análisis univariados (anoVa) y multivariados (componentes principales y de conglomerados) para determinar las variedades putativas presentes. los resultados evidenciaron la existencia de un patrón altitudinal significativo de variación morfológica, en el cual las poblaciones de localidades bajas tienen hojas, semillas y conos más largos que las desarrolladas en lugares con altitudes medias y altas. el análisis multivariado discriminó dos grupos evidentemente distintivos: uno compuesto por individuos de poblaciones originadas entre 1,600 y 1,850 msnm: Pinus devoniana var. devoniana (equivalente a P. michoacana típica), y otro en el que se integraron ejemplares de poblaciones procedentes de sitios ubicados en un intervalo de 1,950 a 2,450 msnm: Pinus devoniana var. cornuta (ex P. michoacana var. cornuta). así, se sugiere la separación de las poblaciones estudiadas de P. devoniana en al menos dos variedades: P. devoniana var. devoniana y P. devoniana var. cornuta.
 
 

Morphological disparity in ecologically diverse versus constrained lineages of Lake Malaŵi rock-dwelling cichlids

Lake Malaŵi cichlids have evolved rapidly, extensively, and in some cases iteratively to fill an array of ecological niches; however, neither species richness nor trophic diversity is distributed equally across lineages. In the context of evolutionary theory, such differences offer predictions about the magnitudes and patterns of morphological variation within lineages. In this paper, we use geometric morphometrics in three prevalent rock-dwelling genera to address questions related to morphological diversity, disparity, integration, and modularity. In particular, we focus on comparisons between the highly specialized and species-poor genus, Labeotropheus (Ahl in Sitzungsberichte der Berlinische Gesellschaft Naturforschender Freunde zu Berlin 1926:51–62, 1927), and the more ecologically diverse and species-rich genus, Tropheops (Trewavas in Revue Francaise d’Aquariologie Herpetologie 10:97–106, 1984), as well as between species with lake-wide versus more limited distributions. We find that Labeotropheus exhibits comparable levels of morphological disparity to Tropheops, which suggests that a specialized foraging mode has not constrained cranial variability in this genus. We also find that species with a lake-wide distribution exhibit levels of disparity three times greater than that in a species with a limited distribution. Finally, we show that magnitudes of integration and patterns of modularity are lineage specific, and do not directly correspond to ecology. In sum, these data provide insights into the complex relationship between ecology, morphological variability, and evolvability.

Molecular and morphological variation in Terniopsis (Podostemaceae) show contrasting patterns

Previous molecular phylogenies of Podostemaceae have indicated relationships between genera and species that are quite different from the pattern of morphological variation, but conclusions have been hampered by too sparse sampling. Here, using new material collected in Cambodia, we compare the morphological variation of Terniopsis chanthaburiensis and T. heterostaminata in Cambodia, Laos and Thailand, and perform a phylogenetic analysis based on matK, including multiple samples of most species of the genus. In contrast to the molecular variation, the morphological variation (e.g. in the length of the shoots and pedicels) is large and continuous. The results indicate that the variation in Terniopsis chanthaburiensis and T. heterostaminata is intraspecific. In two other species pairs the morphological variation was found to be large and discontinuous, while there was little molecular difference. However, the opposite pattern was observed in other cases (e.g. Dalzellia zeylanica and Tristicha trifaria). The variation in T. chanthaburiensis and T. heterostaminata does not appear to be correlated to variation in their habitats, which is submerged rock surfaces in rapid currents. Distributional and phylogenetic data indicate that Terniopsis diversified primarily in Laos and Thailand, then expanded into neighboring regions. A synopsis of the genus Terniopsis and its 14 species is provided.

A new species of Tanaecium (Bignonieae, Bignoniaceae) from the Brazilian Amazon and its phylogenetic placement

Tanaecium (Bignonieae, Bignoniaceae) is a genus of Neotropical lianas that is centered in the Amazon. The genus exhibits interesting patterns of morphological variation, especially in terms of flower morphology. Despite that, the group remains poorly known, lacks a phylogeny and a taxonomic revision. While working on the systematics of Tanaecium, we encountered a morphological variant of Tanaecium pyramidatum from the Brazilian Amazon that represents an independent evolutionary lineage and differs from that species in various morphological traits. This taxon is here described as Tanaecium decorticans, sp. nov. While T. decorticans is sister and most morphologically similar to T. pyramidatum, it differs in the peeling epidermis (vs. not peeling in T. pyramidatum), presence of an arrow-shaped petiolule (vs. absence of an arrow-shaped petiolule in T. pyramidatum), and interpetiolar region covered with fields of glandular trichomes (vs. aglandular interpetiolar region in T. pyramidatum), among other characters. This finding highlights the importance of in-depth taxonomic studies of individual lineages for an improved understanding of the Amazonian biodiversity.

Redescription of the Amazonian tiny tree toad Amazophrynella minuta (Melin, 1941) (Anura: Bufonidae) from its type locality.

The description of Amazophrynella minuta was published in 1941 by the Swedish naturalist Douglas Melin based on material from Taracuá (Amazonas state, Brazil). This description was very brief and based on the morphology of few specimens with diagnostic characters and color variation not well defined. Moreover, the type series is currently in poor state of conservation. Consequently, taxonomic ambiguity surrounds the nominal taxon A. minuta, which hampers the description of many unnamed congeneric species. Herein, we redescribe A. minuta based on recently collected specimens from the type locality, designate a lectotype, formulate a new diagnosis, provide patterns of morphological variation, measurements and body proportions.

Phenotypic changes in the body of black seabream, Spondyliosoma cantharus (Teleostei: Sparidae), along the eastern Atlantic

Knowledge of population spatial structure is essential in fisheries management. The study of morphological variation patterns in fishes can indicate differences in growth and maturation rates, and thus provide information on group dynamics that should be modelled and managed separately. Identification of intraspecific groups which have different life history features is necessary for understanding population dynamics and achieving a sustainable harvest. The black seabream, Spondyliosoma cantharus, has an extensive distribution along the eastern Atlantic Ocean and is an important commercial fish, exploited in European waters by recreational and commercial fishers. In this paper, body geometric morphometrics was used in order to discriminate among black seabream geographical populations caught in seven different geographical areas. The results showed the existence of intraspecific groups of black seabream across the eastern Atlantic Ocean, with Canary and Angola having clear distinct morphotypes and at least four populations in the European Coast (English Channel, Galicia, Peniche and Algarve) that present stable body shape differences. These populations should be considered to be separate and studies on life history parameters should be enhanced and updated.

On Rhinella gildae Vaz-Silva, Maciel, Bastos & Pombal 2015 (Anura: Bufonidae): Phylogenetic relationship, morphological variation, advertisement and release calls and geographic distribution

Anurans in the Rhinella margaritifera group have a long history of taxonomic confusion, mainly by morphological similarity between species and lack of acoustic and genetic data for many of the 19 described species. Herein, we presented data for Rhinella gildae based on recently collected specimens from its type locality. We provide patterns of morphological variation, measurements, advertisement and release calls and infer the phylogenetic position of R. gildae. The species geographical distribution was updated, occurring in two Amazonian localities in Maranhão state, and Cerrado areas in Maranhão and Tocantins states and also in a rainforest enclave inside Caatinga domain in Ceará state.

Spatial variation in the morphological traits of Pocillopora verrucosa along a depth gradient in Taiwan.

Pocillopora verrucosa is a widely distributed depth-generalist coral that presents plasticity in its skeletal macro- and microstructure in response to environmental gradients. Light and water movement, which covary with depth, are the main environmental drivers of morphological plasticity in this genus; however, assessing environmentally-induced plasticity may be confounded by the extent of interspecific variation in Pocillopora. We examine the morphology of 8 typed P. verrucosa specimens collected along a depth gradient ranging from 7 to 45 meters and comprising 3 sites throughout Ludao, Taiwan. We measured 36 morphological characters, 14 which are novel, in 3 regions on the corallum—the apex, branch and base—in order to quantify their relationship to site and depth. We found significant correlation between depth and 19 morphological characters, notably branch verruca area, branch verruca height, base verruca spacing, base spinule length, and branch corallite area. 60% of microstructural characters and 25% of macrostructural characters showed a correlative relation to depth, suggesting that depth acclimatization is manifested primarily at the microstructural level. Canonical discriminant analysis of all morphometric characters by depth supports clustering into 3 groups: an overlapping 7m and 15m group, a 23-30m group, and a 38-45m group. Canonical discriminant analysis by site supports clustering into low- and high-current sites, differentiated primarily by branch septa width, base septa width, pre-terminal branch width, terminal branch maximum length, and terminal branch minimum length. We conclude that distinctive patterns of morphological variation in mesophotic specimens of P. verrucosa could reflect the effects of abiotic parameters such as light and water flow. Elucidating the mechanisms behind the morphological changes that occur in response to environmental gradients can help clarify the role that physiological plasticity plays in the acclimatization of corals to the unique environmental settings of mesophotic coral ecosystems.