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Graphical representation of coding two sets of triangles, 2, transformation that is not parallel to either morphometric axis. A) short symmetrical triangles and tall asymmetrical triangles superimposed at their baselines, E) scatter-plot of shape coordinates of the apical points, C) scatter-plot with arrow to indicate the inferred direction of transformation.
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Abstract Several studies have shown that the recently developed techniques of geometric morphometrics are extremely powerful descriptive tools. And yet, one potential use of the resulting descriptions, phylogenetic analysis, has generally been neglected. This neglect is understandable because prominent systematists as well as prominent morphometric...
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The iconic, palmately compound leaves of Cannabis have attracted significant attention in the past. However, investigations into the genetic basis of leaf shape or its connections to phytochemical composition have yielded inconclusive results. This is partly due to prominent changes in leaflet number within a single plant during development, which...
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... The quantitative analysis of shape is a well-established approach to robustly address questions across a breadth of disciplines and subdisciplines in biology, with broad application in the study of evolution, ecomorphology, development, biogeography, taxonomy and phylogenetics [1][2][3][4][5][6][7][8][9][10]. The ability to capture complex shape data has been greatly expanded by advances in geometric morphometric techniques which improve upon traditional morphometrics by providing the ability to capture information about where the parts of the shape are located with respect to each other in a Cartesian plane. ...
Cranial sutures play critical roles in facilitating postnatal skull development and function. The diversity of function is reflected in the highly variable suture morphology and complexity. Suture complexity has seldom been studied, resulting in little consensus on the most appropriate approach for comparative, quantitative analyses. Here, we provide the first comprehensive comparison of current approaches for quantifying suture morphology, using a wide range of two-dimensional suture outlines across extinct and extant mammals (n = 79). Five complexity metrics (sinuosity index (SI), suture complexity index (SCI), fractal dimension (FD) box counting, FD madogram and a windowed short-time Fourier transform with power spectrum density (PSD) calculation) were compared with each other and with the shape variation in the dataset. Analyses of suture shape demonstrate that the primary axis of variation captured attributes other than complexity, supporting the use of a complexity metric over raw shape data for sutural complexity analyses. Each approach captured different aspects of complexity. PSD successfully discriminates different sutural features, such as looping patterns and interdigitation amplitude and number, while SCI best-captured variation in interdigitation number alone. Therefore, future studies should consider the relevant attributes for their question when selecting a metric for comparative analysis of suture variation, function and evolution.
... Some studies also used GM combined with genetic approaches for species discrimination (Gómez and Correa, 2017;Altamiranda-Saavedra et al., 2017) or even to compare both markers for genetic and phenetic structure of specific populations (Gómez et al., 2014). Furthermore, studies have been conducted using morphometric data to construct phylogenies (Zelditch et al., 1995(Zelditch et al., , 1998Swiderski et al., 2000;Guerrero et al., 2003). This is only possible if there is a strong phylogenetic signal (Cole and Lele, 2002) in the morphometric data. ...
... Despite their weak intraspecific specializations, marmot morphology strongly differs from other squirrels. Mandible and skull shape differentiates marmot from their closest ground squirrel relatives and from sciurids as a whole (Swiderski et al, 2000;Cardini, 2003;Micheaux et al, 2008;Casanovas-Vilar and van Dam, 2013;Lv et al., 2013). The specialized mandible morphology of marmots is functionally associated with their highly herbivorous diets through the proportions of the moment arms of the muscles of mastication (Velhagen and Roth, 1997;Zelditch et al., 2009;Swiderski and Zelditch, 2010;Casanovas-Vilar and van Dam, 2013). ...
Ground squirrels of the genus Marmota are known for their ability to tolerate bitterly cold climates, which they in part accomplish with their exceptional ability to hibernate for as much as eight months a year (Armitage et al., 2003). Most of the 15 living species are associated with montane habitats, and those that are not, like the North American woodchuck (Marmota monax) and the eastern European and central Asian bobak (M. bobak) inhabit regions with strongly seasonal climates and often bitterly cold winters (Armitage, 2000) (Figure 9.1). All marmots construct burrows, which can be more than one metre deep even in comparatively mild climates and as much as seven metres deep in the harsh climates of the Himalayas (Barash, 1989). During the cold phases of the last half of the Quaternary the fossil record demonstrates many marmots inhabited periglacial environments (Zimina and Gerasimov, 1973; Kalthoff, 1999). For these reasons, marmots are sometimes considered to be a quintessentially Quaternary clade, specialists on the cold variable climates that are unique to the past 2.6 million years of Earth’s history. The world in which they originated, however, was very different; a warmer one in which there were no tundra biomes, no glacial-interglacial cycles, and no permanent ice cover in the Northern Hemisphere. In this chapter, we review the fossil and phylogenetic history of marmots, the palaeoenvironments in which they originated, and their relationship to glacial-interglacial cycles to better understand the contexts in which the specializations of this unique clade of rodents arose. The Quaternary, the current geological period, is defined by the onset of permanent ice sheets in the Northern Hemisphere 2.58 million years ago and is by far the coldest period since the extinction of the last non-avian dinosaurs 65 million years ago (Zachos et al., 2001; Gibbard et al., 2010).
... Notable exceptions include: successfully separating Dinaric-Balkan and Carpathian gray wolf populations (Milenkovic et al., 2010), investigating the changing skull morphology in arctic wolves (Clutton-Brock et al., 1994), and measuring the nasal passageways of domestic dogs (Craven et al., 2007). Moreover, similar techniques have proven successful in differentiating variation in cranium and mandibles between two subfamilies of felids (Christiansen, 2008); biomechanical differences in Plethodon salamanders (Adams & Rohlf, 2000); cranial allometry in papionins (Frost et al., 2003); and skull evolution in squirrels (Swiderski et al., 2000). ...
... While previous studies have showed the limited success of linear measurements, GM techniques are able to separate size and shape components, while preserving this information relative to spatial arrangements (Milenkovic et al., 2010;Swiderski et al., 2000). Specifically, traditional measurement techniques limit the ability to describe true shape variation in a given sample (Bookstein, 1991), while GM approaches can provide a true depiction of biological and morphological variation within a population (Hood, 2000;Zelditch et al., 2004). ...
Wild canid populations exhibit different anatomical morphologies compared to domesticated dogs in North America. This is particularly important concerning archaeological sites, which may contain early domesticated species, for the proper identification of osteological remains. Previous studies have indicated domestic dogs exhibit a shorter rostrum accompanied by a crowded tooth row; however, none describe the overall complexity of these changes. Consequently, using a landmark‐based geometric morphometric analysis, cranial morphological characteristics were examined in North American wild canids: the gray wolf (Canis lupus), coyote (Canis latrans), red wolf (Canis rufus), and the domestic dog (Canis familiaris). The shape and size of the cranium in lateral and ventral views were compared between the three wild species to the group of domesticated dogs. Wild canids clustered separately from the domestic group in all statistical analyses. Results indicate an expansion of the orbital region, a compression of the rostrum, and an overall warping in the shape and orientation of the skull. In domestic species, there is also a downward shift in the frontal portion of the skull accompanied by the braincase assuming a more upward position. This technique successfully depicted how slight changes in isolated areas of the cranium can have an impact on the overall shape and morphology of the skull. We presume these changes in cranial anatomy reflect the recent selective pressures domestic dogs have undergone since diverging from their wild ancestors. Copyright © 2012 John Wiley & Sons, Ltd.
... Previous research on geometric morphometrics of rodent molars provides interesting results with regard to describing ecological preferences [7,15,9,16]. The interest of our study is based upon the use of a methodological approach allowing us to analyse the high morphological diversity within extant and extinct murine rodents and to associate it with their feeding habits. ...
... Therefore we analysed the differences in size (M1 length) and shape (allometry) by a linear correlation between size and CV1 and CV2 as shape estimators [38]. Furthermore we analysed the differences in size among the feeding habits through ANOVA and Post-hoc Tukey tests using SPSS v. 15. ...
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ABSTRACT Murine rodents represent a highly diverse group, which displays great ecological versatility. In the present paper we analyse the relationship between dental morphology, on one hand, using geometric morphometrics based upon the outline of first upper molar and the dietary preference of extant murine genera, on the other. This ecomorphological study of extant murine rodents demonstrates that dietary groups can be distinguished with the use of a quantitative geometric morphometric approach based on first upper molar outline. A discriminant analysis of the geometric morphometric variables of the first upper molars enables us to infer the dietary preferences of extinct murine genera from the Iberian Peninsula. Most of the extinct genera were omnivore; only Stephanomys showed a pattern of dental morphology alike that of the herbivore genera.
... Multivariate quantitative approaches to morphology have not been used for terrestrial isopods, in contrast to other organisms, such as aquatic isopods (Bertin et al. 2002), decapods (Mariappan and Balasundram 2004), insects (Rohlf and Archie 1984;Luebke et al. 1988;Monti et al. 2001;Tatsuta et al. 2001Tatsuta et al. , 2004Garnier et al. 2005) and, mostly, vertebrates (e.g. Cavalcanti et al. 1999;Marcus et al. 2000;Swiderski et al. 2000;Corti et al. 2001;Loy et al. 2001;Albertson et al. 2003;Guill et al. 2003;Johnson et al. 2005;Koumoundouros et al. 2005; Monteiro and Dos Reis . It is true that classical morphometrics using linear measurements cannot describe efficiently many morphological features of these soft-bodied crustaceans, due to the ÔflexibilityÕ of their cuticle and the lack of adequate recognizable homologous points on their pleopodal appendages. ...
The terrestrial isopod species Armadillo tuberculatus Vogl, 1876 (Crustacea, Isopoda, Oniscidea) is a widely polymorphic species distributed in the
south-central Aegean region (Greece) with a different morph on each island. Variation consists in coloration, size of cuticular tubercules, shape of
telson and the shape of the male first pleopod exopodite (secondary sexual character of taxonomic importance). We studied the allometric growth
of a cuticular tubercule in 17 populations (for both male and female individuals) and the shape variation of the first male pleopod exopodite in 10
populations using Elliptic Fourier Analysis, in order to test for patterns of intraspecific variation and possible relationships between morphs. In
addition, Thin Plate Spline analysis was used for the calculation of the minimum bending energy between different exopodite shapes, which was
then used for estimating the minimum spanning network (MSN) connecting them. The different allometric growth rates of the tubercule among
island groups were significantly related to island latitude and climatic factors. On the other hand, the clustering of islands and the MSN based on
male exopodite shape differences were not related to the palaeogeography of the Aegean region or to the present geographic distances of islands.
These results are interpreted as evidence for non-adaptive radiation of the morphs.
... The aim of our study was to examine differences in skull morphology of two cryptic species using a 3D geometric morphometrics, with a special focus on their dentary apparatus. This method enables independent descriptions of size and shape, anchors explanations for those differences to specific regions of organisms and recovers geometric properties of the skull shape in three-dimensional space, thus avoiding information loss that can occur when using traditional morphometrics (e.g., Marcus et al., 1996;O'Higgins, 2000;Swiderski et al., 2000;Adams et al., 2004;Zelditch et al., 2004). Although Barlow et al. (1997) analysed differences in skull morphology of the two cryptic species, these morphological characters proved insufficient for a fully reliable identification of specimens. ...
Differences in skull morphology between two cryptic species of bat, Pipistrellus pipistrellus (n = 14) and P. pygmaeus (n = 15), originating from Great Britain, were investigated. Four different data sets were analysed: (1) 23 landmarks and (2) 26 landmarks on the dorsal and ventral sides of the cranium, respectively, (3) 49 landmarks on the upper jaw, and (4) 34 landmarks on the labial side of the mandible. For almost all data sets, when compared within sex groups, P. pipistrellus were significantly larger than P. pygmaeus; the biggest difference being observed in the mandible size. Interspecific differences in shape, analysed by Principal Component Analysis and Discriminant Function Analysis (DFA) of the Procrustes superimposed landmarks, were also mostly visible in the mandible, and were related to dietary differences between the species. For example, the longer and more upright canines of P. pipistrellus allow them to pierce harder prey, the bigger molars ease its processing, and the shortened body of the mandible and the more developed coronoid process presumably generate a stronger bite. The shape and size of the mandible proved to be a good characteristic for distinguishing both cryptic taxa. A procedure for estimating missing landmarks for 3D geometric morphometric purposes was created. Our procedure of finding the missing landmarks had no effect on the within-group loss of variation. DFA of data sets with reconstructed versus orginal (but reduced) landmarks yielded similar results (three versus two misclassified specimens in leave-one-out cross-validation).
... The results obtained from geometric morphometrics show consistency when compared with works of functional morphology (Wainwright, 1988; Wainwright et al., 2004) because they indicate that the variations seen in the labrids occur mainly in the area of the skull. despite the rejection related to the use of data generated by geometric morphometrics for phylogenetic purposes (Fink and zelditch, 1995; Swiderski et al., 1998 Swiderski et al., , 2000 Acero et al., 2005), the results are satisfactory in this and other previous studies. However, caution is suggested in inferring phylogenetic relationships, since the results of morphometric similarities may be reflecting non-homologous and convergent characters due to ecological roles, without representing kinships. ...
A study of geometric morphometries was carried out based on 109 specimens of four Labridae species captured in north-eastern Brazil. The canonical variable analysis applied on the W Matrix discriminated the species, and the partial warps analysis located the morphological variations. According to analysis, the Halichoeres species constitute a monophyletic group, with H. poeyi as the sister-group of the clade H. brasiliensis + H. dimidiatus. The cladogram of these species was estimated using Bodianus rufiis as outgroup. The Halichoeres species share shorter head lengths and deeper heads in relation to the outgroup. Within Halichoeres , the more basal taxon (H. poeyi) can be characterized by autapomor-phies such as short snout and deeper head. In the clade H. brasiliensis + H. dimidiatus , the snout is longer and the caudal peduncle is deeper than in H. poeyi. The results obtained from the geometric morphometry are consistent with works of functional morphology and their applications for the testing of phylogenetic hypotheses are equally satisfactory. However, caution is necessary because the similarities in morphometric data can reflect non-homologous and convergent features due to ecological roles, without representing kinships.
... Para este estudio se seleccionó el método de descomposición "Thin Plate Spline" (TPS), el cual permite analizar los cambios geométricos en una estructura, basándose en los desplazamientos de puntos específicos (Bookstein, 1989(Bookstein, , 1991. Este método ha sido muy utilizado para visualizar y describir variaciones de la forma en diferentes estructuras y ha permitido comparar e inferir patrones de cambio en distintos grupos o taxones de mamíferos, tanto en estudios sistemáticos como ecológicos (Swiderski, 1993;Lynch et al., 1996;Rohlf et al., 1996;Birch, 1997;Bondanowicz y Owen, 1996;Marcus et al., 2000;Swiderski et al., 2000;Corti et al., 2001). En este estudio se utilizaron 82 ejemplares pertenecientes a nueve géneros de sigmodontinos (Necromys, Nectomys, Neacomys, Oecomys, Oligoryzomys, Oryzomys, Rhipidomys, Sigmodon, Zygodontomys) de la Guayana venezolana, los cuales se encuentran preservados en alcohol en diferentes museos de Venezuela (Apéndice 1). ...
Los cambios de forma de la pata posterior fueron comparados y relacionados entre nueve géneros de sigmodontinos de la Guayana venezolana, utilizando la técnica geométrica ¿Thin Plate Spline¿. Los resultados mostraron que entre estos taxones se pueden distinguir tres tipos de forma según sus adaptaciones: terrestres de vegetación boscosa (Neacomys, Oryzomys), terrestres de vegetación abierta (Necromys, Sigmodon, Zygodontomys) y trepadores- arbóreos (Oecomys, Rhipidomys). Los primeros se caracterizan por presentar una superficie plantar alargada, dedos medios largos y garras cortas; los segundos presentan dedos cortos y garras largas; y los terceros superficie plantar y garras cortas, y dedos largos. En la forma semiacuática (Nectomys) la pata fue similar a los terrestres de vegetación boscosa, mientras que Oligoryzomys, considerando dentro de los terrestres, presentó más semejanza con los trepadores-arbóreos.
Within Menispermaceae, endocarp shape is highly variable and often characteristic. This study applied geometric morphometrics to the investigation of horseshoe–shaped endocarps that characterized the former Menispermeae tribe. The shape of 823 endocarp specimens, representing 66 species and 16 genera, were described on the lateral face by the means of 4 landmarks and 18 semilandmarks. The general Procrustes analysis was used to remove size and orientation of the specimens. Using thin–plate splines, we were able to visualize and describe the variation in shape for each genus and/or species. The main differences concern the symmetry/asymmetry of endocarp, the relative size of condyle, the relative length of ventral face and the concavity of ventral face. The results of a PCA reveal that for all genera except Diploclisia, generic variability is explained by a continuum in intra– and interspecific variability. Endocarp shape differed significantly between genera, demonstrating the potential for geometric morphometrics in fossil identification. Allometry explained only a small part of shape variation. Phylogenetic content is evaluated by comparing the results of cluster analysis with recent molecular phylogenies. Endocarp shape affinities appear to be quite different from phylogenetic relationships, demonstrating the low phylogenetic signal in endocarp shape at the family level. However, stronger variation is found in the lineages leading to modern genera. With a known phylogeny, geometric morphometrics is a good tool to understand shape evolution.
