scholarly journals Quantifying the Geometric Shell Shape between Populations of True Limpets Lottia Mesoleuca (Mollusca: Lottidae) in Colombia

Animals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 675
Author(s):  
Ana María Echeverry ◽  
Edgardo Londoño-Cruz ◽  
Hugo A. Benítez

The increasing activity in morphological studies has provided new tools to analyses the shape quantitatively, these quantitative measurements allow the researcher to examine the variation in shape and perform analysis to examine the quantitative differences among the species shapes, where geometric morphometrics has rendered great results in the last years. This study was focused on assessing the morphometric variation between populations of Lottia mesoleuca of the family Lottidae, an abundant group of gastropods in the rocky ecosystems of Bahía Málaga and Isla Gorgona (Colombian Pacific). This family has a high morphological diversity, making the identification of some morphotypes problematic work. Geometric morphometrics methods were applied on the shell using dorsal, lateral and ventral views. Different multivariate analyses were performed to differentiate the groups of species and populations (principal component analysis, morphological distances comparisons and grouping analysis by means of the Ward method). The results indicate that individuals of the species Lottia mesoleuca have key geometric characteristics associated to the different populations (depth intertidal zones) for classification, being the geometric shape of the shell enough to determine morphotypes between the different populations studied. Aspects associated with the combination of ecological variables with morphometric ones are necessary to be able to visualize with a higher resolution the structural complexity of populations and their adaptation processes. Furthermore, it is obvious that there is a strong need to conduct more explorations of environmental and ecological processes that provide some insight on why the morphological characteristics are so variable in the same species.

2016 ◽  
Vol 64 (4) ◽  
Author(s):  
Edna Judith Márquez ◽  
Natalia Restrepo-Escobar ◽  
Francisco Luis Montoya-Herrera

The endangered species Strombus gigas is a marine gastropod of significant economic importance through the Greater Caribbean region. In contrast to phenotypic plasticity, the role of genetics on shell variations in S. gigas has not been addressed so far, despite its importance in evolution, management and conservation of this species. This work used geometric morphometrics to investigate the phenotypic variation of 219 shells of S. gigas from eight sites of the Colombian Southwest Caribbean. Differences in mean size between sexes and among sites were contrasted by analysis of variance. Allometry was tested by multivariate regression and the hypothesis of common slope was contrasted by covariance multivariate analysis. Differences in the shell shape among sites were analyzed by principal component analysis. Sexual size dimorphism was not significant, whereas sexual shape dimorphism was significant and variable across sites. Differences in the shell shape among sites were concordant with genetic differences based on microsatellite data, supporting its genetic background. Besides, differences in the shell shape between populations genetically similar suggest a role of phenotypic plasticity in the morphometric variation of the shell shape. These outcomes evidence the role of genetic background and phenotypic plasticity in the shell shape of S. gigas. Thus, geometric morphometrics of shell shape may constitute a complementary tool to explore the genetic diversity of this species.


2015 ◽  
Vol 43 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Y Bakis ◽  
MT Babaç

Morphological variations of acorn among and within the groups of Quercus species were studied. A total of 617 acorns belonging to 14 species representing all 3 sections of Quercus L. (Fagaceae) in Turkey were examined in this study. Specimens were collected from 47 different populations over both Anatolian and Thrace part of Turkey. Principal component analysis was used to analyze the morphological characteristics of acorns. Results obtained from this study demonstrate the use of morphological characters in differentiating the taxa of Quercus and Cerris sections studied. Another important finding is the introgression among the acorns of species within Quercus section DOI: http://dx.doi.org/10.3329/bjb.v43i3.21601 Bangladesh J. Bot. 43(3): 293-299, 2014 (December)


2014 ◽  
Vol 49 (8) ◽  
pp. 604-612 ◽  
Author(s):  
Julcéia Camillo ◽  
Valentine Carpes Braga ◽  
Jean Kleber de Abreu Mattos ◽  
Ricardo Lopes ◽  
Raimundo Nonato Vieira da Cunha ◽  
...  

The objective of this work was to evaluate the morphological diversity of oil palm seeds and to cluster the accessions according to their morphological characteristics. Forty-one accessions from the oil palm germplasm bank of Embrapa Amazônia Ocidental were evaluated - 18 of Elaeis oleifera and 23 of E. guineensis. The groups were formed based on morphological characteristics, by principal component analysis. In E. oleifera, four groups were formed, tied to their region of origin, but with significant morphological differences between accessions from the same population. For tenera-type E. guineensis seeds, three widely divergent groups were formed, especially as to external parameters, which differentiated them from the other ones. The parameter endocarp thickness stood out in intra- and inter-population differentiation. For dura-type E. guineensis, three groups were formed, with larger seeds and thicker endocarps, which differed from all the other ones. The variability observed for seed characteristics in the analyzed accessions allows the establishment of different groups, to define strategies for genetic improvement.


2016 ◽  
Vol 90 (6) ◽  
pp. 1027-1048 ◽  
Author(s):  
Kun Liang ◽  
Robert J. Elias ◽  
Suk-Joo Choh ◽  
Dong-Chan Lee ◽  
Dong-Jin Lee

AbstractCatenipora is one of the most common tabulate coral genera occurring in various lithofacies in the Upper Ordovician Xiazhen Formation at Zhuzhai in South China. A combination of traditional multivariate analysis and geometric morphometrics is applied to a large number of specimens to distinguish and identify species. Based on three major principal components extracted from 11 morphological characters, three major groups as determined by the cluster-analysis dendrogram are considered to be morphospecies. Their validity and distinctiveness are confirmed by discriminant analysis, descriptive statistics, and bivariate plots. Tabularium area and common wall thickness are the most meaningful characters to distinguish the three morphospecies. Geometric morphometrics is adopted to compare the morphospecies with types and/or figured specimens of species previously reported from the vicinity of Zhuzhai. Despite discrepancies in corallite size, principal component analysis and discriminant analysis, as well as consideration of overall morphological characteristics, indicate that the morphospecies represent C. zhejiangensis Yu in Yu et al., 1963, C. shiyangensis Lin and Chow, 1977, and C. dianbiancunensis Lin and Chow, 1977.Catenipora occurs in seven stratigraphic intervals in the Xiazhen Formation at Zhuzhai, representing a variety of heterogeneous environments. The coralla preservation is variable due to differential compaction; coralla preserved in limestones are commonly intact and in growth position, whereas those in shales are mostly crushed or fragmentary. The size and shape of corallites are considered primarily to be species-specific characters, but are also related to the depositional environments. In all species, morphological characters, including corallite size, septal development, and shape and size of lacunae, show high variability in accordance with lithofacies and stratigraphic position. The intraspecific differences in corallite size at various localities in the Zhuzhai area may indicate responses to local environmental factors, but may also reflect genetic differences if there was limited connection among populations.


2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Fauziyah FAUZIYAH ◽  
APON Z. MUSTOPA ◽  
FATIMAH FATIMAH ◽  
ANNA I. S. PURWIYANTO ◽  
ROZIRWAN ROZIRWAN ◽  
...  

Abstract. Fauziyah, Mustopa AZ, Fatimah, Purwiyanto AIS, Rozirwan, Agustriani F, Putri WAE. 2021. Morphometric variation of the horseshoe crab Tachypleus gigas (Xiphosura: Limulidae) from the Banyuasin estuarine of South Sumatra, Indonesia. Biodiversitas 22: 5061-5070. Morphological studies are essential for fish resource management, ecology, conservation, and stock assessment. This research was conducted to characterize the morphological variation of the coastal horseshoe crab (Tachypleus gigas) from the Banyuasin estuarine, South Sumatra, Indonesia. The body weight (BW), prosoma width (PW), carapace length (CL), telson length (TEL), and total length (TL) were measured for describing the morphometric variability of T. gigas. A total of 70 T. gigas (32 females and 38 males) were found using trammel net fishing and bottom gillnet during the survey. Multivariate and allometric methods analyzed their morphometric characters. Based on Kruskal- Wallis tests, the result showed a significant difference in somebody measurements (TL and CL) between males and females. The principal component analysis (PCA) results showed that all morphometric characters had a strong correlation in both sexes, so the first principal component (PC1) values were 92% and 72%. In comparison, the second principal component (PC2) values were 5% and 20% in females and males, respectively. The results of discriminant function analysis (DFA) suggested that only one (BW) of the five morphometric characters was significant in separating both sexes. Both sexes were also revealed variations in growth patterns based on the allometric analysis results. These results were expected to be used as a basis for managing the horseshoe crab population-based conservation.


1991 ◽  
Vol 48 (11) ◽  
pp. 2140-2151 ◽  
Author(s):  
Thomas A. Edge ◽  
Don E. McAllister ◽  
Sami U. Qadri

Principal component and discriminant function analyses of morphological variation between whitefish populations from the Canadian Maritime Provinces and the State of Maine, USA, clearly distinguished the Acadian whitefish, Coregonus huntsmani, from the lake whitefish species complex, Coregonus clupeaformis. Ten meristic and 44 morphometric characters were examined and the species were best discriminated by number of vertebrae (>97% separation) and mouth shape. Acadian whitefish had a terminal mouth and 64–67 [Formula: see text] vertebrae, while lake whitefish had a subterminal mouth and 58–64 [Formula: see text] vertebrae. Acadian whitefish were also characterized by having more lateral line scales (88–100, [Formula: see text] than lake whitefish (63–95, [Formula: see text], a shorter adipose to caudal fin length, a smaller adipose fin, and a longer pelvic axillary process than lake whitefish. Considerable morphological variation was found between lake whitefish populations examined although there was no morphological basis to recognize any lake whitefish population as taxonomically distinct. The Acadian whitefish has morphological characteristics of both subgenera Leucichthys and Coregonus; it could be important for understanding the evolution of coregonine fishes and its imminent extinction would represent a serious loss of genetic diversity.


Caryologia ◽  
2021 ◽  
Author(s):  
Pelin Yilmaz Sancar ◽  
Semsettin CIVELEK ◽  
Murat KURSAT

Artemisia is one of the biggest genera in the family Asteraceae, with around 500-600 taxa at specific and sub-specific levels and organised in five subgenera. Due to the high number of taxa, a lot taxonomists are trying to solve the problem of its classification and phylogeny but its natural classification still has not been achieved.The aim of this study is to try to solve the problematic systematic relationship between three different Artemisia species growing in close proximity to each other in the light of morphological, karyological and molecular data.The roots, stems, leaves, flowers structures of the plant samples collected from different populations belong to these species were investigated within the framework of morphological studies. Additionally, the chromosome counts and karyotype analysises of these species were made and idiograms were drawn in the karyological studies. In the context of phylogenetic studies, ITS and trn regions of 22 individuals belonging to 3 taxa were studied. It has been found that there is complete speciation genetic isolation mechanism between the species A. spicigera, A. taurica and A. fragrans that inhibit gene flow. A. fragrans and A. spicigera species are very similar to each other in terms of morphological characteristics. However, since populations of the species a fragrans are otopolyploid, the dimensional values of their morphological squares are larger than those of the species A. spicigera.This study is important as it is the first molecular based study relating with some species of Artemisia growing naturally in Turkey.


Paleobiology ◽  
2016 ◽  
Vol 43 (1) ◽  
pp. 68-84 ◽  
Author(s):  
Bradley Deline ◽  
William I. Ausich

AbstractA priori choices in the detail and breadth of a study are important in addressing scientific hypotheses. In particular, choices in the number and type of characters can greatly influence the results in studies of morphological diversity. A new character suite was constructed to examine trends in the disparity of early Paleozoic crinoids. Character-based rarefaction analysis indicated that a small subset of these characters (~20% of the complete data set) could be used to capture most of the properties of the entire data set in analyses of crinoids as a whole, noncamerate crinoids, and to a lesser extent camerate crinoids. This pattern may be the result of the covariance between characters and the characterization of rare morphologies that are not represented in the primary axes in morphospace. Shifting emphasis on different body regions (oral system, calyx, periproct system, and pelma) also influenced estimates of relative disparity between subclasses of crinoids. Given these results, morphological studies should include a pilot analysis to better examine the amount and type of data needed to address specific scientific hypotheses.


1983 ◽  
Vol 61 (6) ◽  
pp. 1232-1241 ◽  
Author(s):  
Richard R. Snell ◽  
Kimberly M. Cunnison

Analyses of geographic variation in the skull of meadow voles (Microtus pennsylvanicus) indicate that phenetic distances among samples are not related to geographic distance: a minimum spanning tree based on average taxonomic distance superimposed on a map of 38 localities provides no particular phenetic clustering of those samples geographically proximate. A multiple regression of phenetic component one (skull size) onto orthogonally rotated climatic factors explains much less morphometric variation (25.6%) than a simple correlation with recorded extreme low temperature (38.9%). Multiple regression of phenetic principal component two (interorbital width) onto the same climatic factors explains minimally more morphological variation (42.1%) than a simple correlation with mean annual number of days with frost (41.7%). Microtus pennsylvanicus shows a pattern of size variation that is the reverse of Bergmann's rule: these voles are large where it is warm and small where it is cold. Since small size reduces total energy expenditure, we predict that during times of extreme low temperature (i) smaller voles will be less energetically stressed than larger voles and (ii) large size will be actively selected against.


1953 ◽  
Vol 31 (3) ◽  
pp. 211-225 ◽  
Author(s):  
C. C. Lindsey

Anal fin rays were counted on 4766 specimens of Richardsonius balteatus from 61 localities in British Columbia. Individual counts varied from 10 to 21, and mean counts of different populations varied from 12.06 to 17.51. Significant differences in counts occurred between different bodies of water, between recently introduced populations and their parent stock, between different parts of the same lake, and between different year classes. Ray counts tended to be higher amongst females in populations with high over-all means, and higher amongst males in populations with low over-all means. A positive correlation was demonstrated between water temperatures recorded in the vicinity of developing fry and the mean numbers of anal rays produced. Within each latitudinal zone a similar correlation occurred between mean ray count and average air temperature during the spawning season, but data on 109 means of populations in U.S.A. and Canada indicated a tendency, probably genetic, towards production, at equivalent temperature, of higher ray count towards the northern end of the range. Loose correlations between anal ray count and certain other morphological characteristics suggest that these may be dependent on more or less common environmental factors but are not linked by direct causality.


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