Ontogenetic skull variation in an Amazonian population of lowland tapir, Tapirus terrestris (Mammalia: Perissodactyla) in the department of Loreto, Peru

ABSTRACT The skulls of 54 specimens of the South American tapir, Tapirus terrestris collected in the department of Loreto, Peru were measured, analyzed and compared to investigate skull development of this species. Univariate, multivariate and allometric analyses were performed using 32 skull variables through traditional morphometrics. Significant skull shape variation was detected among ontogenetic classes. Young individuals (class I, n = 22) showed higher variation than subadults and adults (class II, n = 23 and class III, n = 9), without evidence of sexual dimorphism (males = 35, females = 19). Principal component analyses and discriminant function analysis showed almost complete separation of the age classes. Allometric analysis indicated a tendency of unproportioned cranial growth. All our samples come from the same population living under the same ecological condition, which eliminates the effect of confounding variables related to habitat on the pattern of ontogenetic variation of this anatomical structure.

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Intraspecific phenotype variations in olive barb Systomus sarana (Hamilton, 1822) population from different rivers is possibly linked to locomotive adaptations in caudal fin

Indian Journal of Fisheries ◽

10.21077/ijf.2020.67.3.102563-03 ◽

2020 ◽

Vol 67 (3) ◽

Author(s):

Jyotsnarni Biswal ◽

Rajeev K. Singh ◽

Sangeeta Mandal ◽

Rejani Chandran ◽

Achal Singh ◽

...

Keyword(s):

Thin Plate ◽

Function Analysis ◽

Principal Component ◽

Strain Ratio ◽

River Basins ◽

Important Variable ◽

Dorsal Side ◽

Thin Plate Spline ◽

Shape Variation ◽

Caudal Fin

Systomus sarana (Hamilton, 1822) [D1] is an economically important food fish species occurring throughout Indian rivers, which also has ornamental value. This study focused on morphological variations in S. sarana from five river basins across India, viz., Godavari, Mahanadi, Krishna, Middle Ganga and Lower Ganga. A truss network was constructed by interconnecting 12 landmarks to generate 65 morphometric variables extracted from digital images of specimens sampled from the study locations. Transformed truss measurements were subjected to Principal component analysis (PCA), Canonical discriminant function analysis (CDFA), Box plot and Thin plate spline (TPS) analyses. PCA identified eight truss variables with significant loadings, while CDFA designated two truss variables with potential for explaining discrimination between populations. Anterior attachment of dorsal membrane from caudal fin was identified to be the most important variable that presented variations across the river basins studied. Discriminant analysis correctly classified 70.5% of the specimens into their original populations. Thin plate spline for morphometric shape variation analysis indicated highest specimen-shape variations (warping) in Mahanadi basin. TPS-principal strain ratio on principal components (PC-1, PC-2) further revealed significant divergence among the populations in five river basins studied. Results of the study revealed variation in stocks of the species, on the basis of shape morphometry. The four significant parameters, differentiating specimens from different basins, were linked to caudal fin origin at dorsal side and the centre and possibly indicate plasticity in response to locomotive adaptations.

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Variation of the Three-Dimensional Femoral J-Curve in the Native Knee

Journal of Personalized Medicine ◽

10.3390/jpm11070592 ◽

2021 ◽

Vol 11 (7) ◽

pp. 592

Author(s):

Sonja A. G. A. Grothues ◽

Klaus Radermacher

Keyword(s):

Geometric Parameter ◽

Knee Kinematics ◽

Size Variation ◽

Principal Component ◽

Parameter Analysis ◽

Patient Specific ◽

3D Analysis ◽

Relative Location ◽

Shape Variation ◽

J Curve

The native femoral J-Curve is known to be a relevant determinant of knee biomechanics. Similarly, after total knee arthroplasty, the J-Curve of the femoral implant component is reported to have a high impact on knee kinematics. The shape of the native femoral J-Curve has previously been analyzed in 2D, however, the knee motion is not planar. In this study, we investigated the J-Curve in 3D by principal component analysis (PCA) and the resulting mean shapes and modes by geometric parameter analysis. Surface models of 90 cadaveric femora were available, 56 male, 32 female and two without respective information. After the translation to a bone-specific coordinate system, relevant contours of the femoral condyles were derived using virtual rotating cutting planes. For each derived contour, an extremum search was performed. The extremum points were used to define the 3D J-Curve of each condyle. Afterwards a PCA and a geometric parameter analysis were performed on the medial and lateral 3D J-Curves. The normalized measures of the mean shapes and the aspects of shape variation of the male and female 3D J-Curves were found to be similar. When considering both female and male J-Curves in a combined analysis, the first mode of the PCA primarily consisted of changes in size, highlighting size differences between female and male femora. Apart from changes in size, variation regarding aspect ratio, arc lengths, orientation, circularity, as well as regarding relative location of the 3D J-Curves was found. The results of this study are in agreement with those of previous 2D analyses on shape and shape variation of the femoral J-Curves. The presented 3D analysis highlights new aspects of shape variability, e.g., regarding curvature and relative location in the transversal plane. Finally, the analysis presented may support the design of (patient-specific) femoral implant components for TKA.

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Morphometrical and molecular evidence suggests cryptic diversity among hookworms (Nematoda: Uncinaria) that parasitize pinnipeds from the south-eastern Pacific coasts

Journal of Helminthology ◽

10.1017/s0022149x18000950 ◽

2018 ◽

Vol 94 ◽

Cited By ~ 1

Author(s):

M.T. González ◽

Z. López ◽

J.J. Nuñez ◽

K.I. Calderón-Mayo ◽

C. Ramírez ◽

...

Keyword(s):

Large Subunit ◽

Principal Component ◽

Eastern Pacific ◽

Lsu Rdna ◽

Molecular Evidence ◽

South American ◽

Southern Chile ◽

The South ◽

South Eastern ◽

Neophoca Cinerea

AbstractHookworms of the genus Uncinaria parasitize pinniped pups in various locations worldwide. Four species have been described, two of which parasitize pinniped pups in the southern hemisphere: Uncinaria hamiltoni parasitizes Otaria flavescens and Arctocephalus australis from the South American coast, and Uncinaria sanguinis parasitizes Neophoca cinerea from the Australian coast. However, their geographical ranges and host specificity are unknown. Uncinaria spp. are morphologically similar, but molecular analyses have allowed the recognition of new species in the genus Uncinaria. We used nuclear genetic markers (internal transcribed spacer (ITS) and large subunit (LSU) rDNA) and a mitochondrial genetic marker (cytochrome c oxidase subunit I (COI)) to evaluate the phylogenetic relationships of Uncinaria spp. parasitizing A. australis and O. flavescens from South American coasts (Atlantic and Pacific coasts). We compared our sequences with published Uncinaria sequences. A Generalized Mixed Yule Coalescent (GMYC) analysis was also used to delimit species, and principal component analysis was used to compare morphometry among Uncinaria specimens. Parasites were sampled from A. australis from Peru (12°S), southern Chile (42°S), and the Uruguayan coast, and from O. flavescens from northern Chile (24°S) and the Uruguayan coast. Morphometric differences were observed between Uncinaria specimens from both South American coasts and between Uncinaria specimens from A. australis in Peru and southern Chile. Phylogenetic and GMYC analyses suggest that south-eastern Pacific otariid species harbour U. hamiltoni and an undescribed putative species of Uncinaria. However, more samples from A. australis and O. flavescens are necessary to understand the phylogenetic patterns of Uncinaria spp. across the South Pacific.

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Individual variation of the masticatory system dominates 3D skull shape in the herbivory-adapted marsupial wombats

10.1101/692632 ◽

2019 ◽

Author(s):

Vera Weisbecker ◽

Thomas Guillerme ◽

Cruise Speck ◽

Emma Sherratt ◽

Hyab Mehari Abraha ◽

...

Keyword(s):

Individual Variation ◽

Principal Component ◽

Individual Variability ◽

Shape Variation ◽

Mandibular Ramus ◽

Geometric Morphometric ◽

Skull Shape ◽

Marsupial Species ◽

Masticatory System ◽

The Individual

AbstractBackgroundWithin-species skull shape variation of marsupial mammals is widely considered low and strongly size-dependent (allometric), possibly due to developmental constraints arising from the altricial birth of marsupials. However, species whose skulls are impacted by strong muscular stresses – particularly those produced through mastication of tough food items – may not display such intrinsic patterns very clearly because of the known plastic response of bone to muscle activity of the individual. In such cases, shape variation should not be dominated by allometry; ordination of shape in a geometric morphometric context through principal component analysis (PCA) should reveal main variation in areas under masticatory stress (incisor region/zygomatic arches/mandibular ramus); but this main variation should emerge from high individual variability and thus have low eigenvalues.ResultsWe assessed the evidence for high individual variation through 3D geometric morphometric shape analysis of crania and mandibles of thre species of grazing-specialized wombats, whose diet of tough grasses puts considerable strain on their masticatory system. As expected, we found little allometry and low Principal Component 1 (PC1) eigenvalues within crania and mandibles of all three species. Also as expected, the main variation was in the muzzle, zygomatic arches, and masticatory muscle attachments of the mandibular ramus. We then implemented a new test to ask if the landmark variation reflected on PC1 was reflected in individuals with opposite PC1 scores and with opposite shapes in Procrustes space. This showed that correspondence between individual and ordinated shape variation was limited, indicating high levels of individual variability in the masticatory apparatus.DiscussionOur results are inconsistent with hypotheses that skull shape variation within marsupial species reflects a constraint pattern. Rather, they support suggestions that individual plasticity can be an important determinant of within-species shape variation in marsupials (and possibly other mammals) with high masticatory stresses, making it difficult to understand the degree to which intrinsic constraint act on shape variation at the within-species level. We conclude that studies that link micro- and macroevolutionary patterns of shape variation might benefit from a focus on species with low-impact mastication, such as carnivorous or frugivorous species.

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Sub-clustering in skeletal class III malocclusion phenotypes via principal component analysis in a southern European population

Scientific Reports ◽

10.1038/s41598-020-74488-w ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

L. de Frutos-Valle ◽

C. Martin ◽

J. A. Alarcón ◽

J. C. Palma-Fernández ◽

R. Ortega ◽

...

Keyword(s):

Adult Population ◽

Principal Component ◽

Class Iii ◽

Cross Sectional ◽

European Origin ◽

Skeletal Class ◽

Skeletal Malocclusion ◽

Clustering Model ◽

Radiographic Measurements ◽

Phenotypic Clustering

Abstract The main aim of this study was to generate an adequate sub-phenotypic clustering model of class III skeletal malocclusion in an adult population of southern European origin. The study design was conducted in two phases, a preliminary cross-sectional study and a subsequent discriminatory evaluation by main component and cluster analysis to identify differentiated skeletal sub-groups with differentiated phenotypic characteristics. Radiometric data from 699 adult patients of southern European origin were analyzed in 212 selected subjects affected by class III skeletal malocclusion. The varimax rotation was used with Kaiser normalization, to prevent variables with more explanatory capacity from affecting the rotation. A total of 21,624 radiographic measurements were obtained as part of the cluster model generation, using a total set of 55 skeletal variables for the subsequent analysis of the major component and cluster analyses. Ten main axes were generated representing 92.7% of the total variation. Three main components represented 58.5%, with particular sagittal and vertical variables acting as major descriptors. Post hoc phenotypic clustering retrieved six clusters: C1:9.9%, C2:18.9%, C3:33%, C4:3.77%, C5:16%, and C6:16%. In conclusion, phenotypic variation was found in the southern European skeletal class III population, demonstrating the existence of phenotypic variations between identified clusters in different ethnic groups.

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Variability of leaf blade anatomical traits in the Sesleria juncifolia complex (Poaceae) on the Balkan Peninsula

Phytotaxa ◽

10.11646/phytotaxa.442.3.2 ◽

2020 ◽

Vol 442 (3) ◽

pp. 138-152

Author(s):

TIJANA ĐENADER ◽

DMITAR LAKUŠIĆ ◽

NEVENA KUZMANOVIĆ

Keyword(s):

Cross Sections ◽

Leaf Blade ◽

Function Analysis ◽

A Priori ◽

Principal Component ◽

Balkan Peninsula ◽

Character State ◽

Adaxial Side ◽

Qualitative Characters ◽

Different Populations

This paper presents the results of a detailed study of leaf blade anatomical traits of populations of the Sesleria juncifolia complex from the Balkan Peninsula. The measurements were performed on cross sections of 302 tiller leaf blades from 24 populations. We calculated basic descriptive statistics for each character state. Principal component and canonical discriminant analyses were used to identify the structure of variability and the characters that majorly contributed to the differentiation of the defined groups. Cluster analysis was done to estimate the distances among the studied populations. We provide a detailed description of the leaf blade anatomy of the different populations of S. juncifolia complex investigated within Croatia, Bosnia and Herzegovina, Montenegro, Serbia and North Macedonia. The results show that most of the characters exhibit moderate degrees of variation. The principal component analysis shows slight separation of populations from northwestern Croatia. Canonical discriminant analysis shows that the three a priori defined groups—three species, S. interrupta, S. juncifolia and S. ujhelyii, can be distinguished based on leaf blade anatomical characters. In addition to the characters that were singled out as statistically most significant for differentiation of the three species in discriminant function analysis, the most useful characters for their delimitation are the length of the trichomes on the adaxial side of the leaf, as well as qualitative characters such as the sclerenchyma on the abaxial side of the leaf (continuous or interrupted) and the type of indumentum of the adaxial side of the leaf (very hairy, hairs long vs. very weakly hairy, hairs short). The northwestern populations of S. juncifolia mostly have glabrous leaves or single hairs on the adaxial side of the leaf, while in S. interrupta and S. ujhelyii populations, individuals always have hairy leaves. The presence of continuous subepidermal sclerenchyma has proven to be a good differential character for separating S. ujhelyii from the S. juncifolia and S. interrupta.

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Two new species of lizards from the Liolaemus lineomaculatus section (Squamata: Iguania: Liolaemidae) from southern Patagonia

Zootaxa ◽

10.11646/zootaxa.3120.1.1 ◽

2011 ◽

Vol 3120 (1) ◽

pp. 1 ◽

Cited By ~ 10

Author(s):

MARIA FLORENCIA BREITMAN ◽

MICAELA PARRA ◽

CRISTIAN HERNÁN FULVIO PÉREZ ◽

JACK WALTER SITES, JR.

Keyword(s):

New Species ◽

Analysis Of Variance ◽

Genetic Characterization ◽

Function Analysis ◽

Univariate Analysis ◽

Principal Component ◽

Genetic Distances ◽

Southern Patagonia ◽

Two New Species ◽

Genetic Characters

Two new species of the lineomaculatus clade of the Liolaemus lineomaculatus section are described from southern Patagonia in Argentina. Liolaemus morandae sp. nov. is found in S Chubut province and Liolaemus avilae sp. nov. inhabits NW Santa Cruz province. Several tests were performed to diagnose these new species as distinct lineages. Univariate analysis of variance (ANOVA), principal component analysis (PCA), discriminant function analysis (DFA), non-parametric multivariate analysis of variance (NPMANOVA), as well as a genetic characterization through molecular analysis of variance (AMOVA) were performed; genetic distances between described and these new species are reported. The new Liolaemus species differ from other members of the lineomaculatus group in morphometric, meristic, qualitative and genetic characters; moreover they inhabit different phytogeographical provinces and districts. With these descriptions, the number of species now recognized in the lineomaculatus section is twenty one (including one more description that is in press).

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A Study of Intraseasonal Temperature Variability in Southeastern South America

Journal of Climate ◽

10.1175/jcli-d-11-00482.1 ◽

2012 ◽

Vol 25 (17) ◽

pp. 5892-5903 ◽

Cited By ~ 4

Author(s):

Gustavo Naumann ◽

Walter M. Vargas

Keyword(s):

Principal Component ◽

Bimodal Distribution ◽

Daily Basis ◽

First Century ◽

Maximum Temperature ◽

Daily Maximum ◽

South American ◽

Regional Variability ◽

Temperature Forecasting

Abstract The main goal of this work was to conduct an intraseasonal climate variability analysis using wavelet and principal component analysis over a southeastern South American daily maximum and minimum temperature series from the end of the nineteenth until the beginning of the twenty-first century. The analysis showed that there is a definite and coherent signal in the intraseasonal maximum and minimum temperatures. The most noticeable signal was observed during the winter months. The frequency of the intraseasonal signal was more complex for the maximum temperature, and in some stations, it displayed a bimodal distribution. A defined pattern that described a coherent variability between 30 and 60 days throughout the entire region was observed. This pattern potentially allows classification of the regional variability and adjustments to the temperature forecasting models on a daily basis.

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Phenotypic variation of south-western Atlantic clam Mactra isabelleana (Bivalvia: Mactridae)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315412000410 ◽

2012 ◽

Vol 93 (2) ◽

pp. 511-517 ◽

Cited By ~ 7

Author(s):

Javier H. Signorelli ◽

Federico Márquez ◽

Guido Pastorino

Keyword(s):

Principal Component ◽

Shell Shape ◽

Physical Parameters ◽

Buenos Aires Province ◽

Shape Variation ◽

Geometric Morphometric ◽

Western Atlantic ◽

Canonical Variates Analysis ◽

Canonical Variates ◽

Geometric Morphometric Method

The phenotypic shell shape variation of Mactra isabelleana was tested using the geometric morphometric method. Four localities were sampled along the Río de la Plata estuary and the coast of Buenos Aires province. Principal component analysis and canonical variates analysis of the first principal components were performed to reveal the shell variation and differences among localities, respectively. The specimens from different microhabitats mostly overlapped, although differences in shape were observed in the development of the umbo, the enlargement of the dorsoventral axes and the elongation of the posterior end. The ecological and physical parameters that could influence shell shape variation are discussed.

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A postura locomotora de Protolipterna ellipsodontoides Cifelli, 1983 (Mammalia: Litopterna: Protolipternidae) da Bacia de São José de Itaboraí, Rio de Janeiro (Paleoceno superior)

Anuário do Instituto de Geociências - UFRJ ◽

10.11137/2007_1_58-66 ◽

2007 ◽

Vol 30 (1) ◽

pp. 58-66

Author(s):

Ana Carolina Fortes Bastos ◽

Lílian Paglarelli Bergqvist

Keyword(s):

Principal Component Analysis ◽

Multivariate Analysis ◽

Rio De Janeiro ◽

Function Analysis ◽

Principal Component ◽

Postcranial Morphology ◽

Foot Posture ◽

Fissure Fill ◽

Large Groups ◽

Janeiro State

The Litopterna is a group of endemic South America ungulates that lived from Late Paleocene (Itaboraiense) to Late Pleistocene (Lujanense). The order is divided in two large groups based on dental features: the Bunolipterna, in which the Protolipternidae is placed, is composed by taxa with primitive bunodont teeth; and the Lopholipterna, grouping taxa with derived lophodont teeth. In both the postcranial morphology is derived and uniform since the early forms. The Itaborai Basin, located at São José district, Itaboraí city, Rio de Janeiro state, is filled with different kinds of limestones, cut vertically by fissure fill deposits, where most of the fossils were collected. Protolipterna ellipsodontoides was described in 1983 based on dental features, but later postcranial bones were associated to this species. The main goal of this article is to infer the foot posture of P. ellipsodontoides. The material studied consists of femora, astragali, calcanea and metatarsals III, comprising 165 bones. All fossils were deposited in the fossil mammal collection of Departamento Nacional da Produção Mineral, in Rio de Janeiro state, Brasil. The methodology employed consisted of 15 linear and curvilinear measurements, which were submitted to a multivariate analysis (Principal Component Analysis -PCA and Discriminant Function Analysis -DFA). The results suggested a digitigrade posture to P. ellipsodontoides. Other morphological features of the skeleton, associated with a digitigrades posture, are suggestive of a cursorial locomotion, but with probable saltatory habits.

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