Salinity and Egg Shape Variation: A Geometric Morphometric Analysis

Murray, Christopher M.; Piller, Kyle R.; Merchant, Mark; Cooper, Amos; Easter, Michael

doi:10.1670/11-123

Cited by 7 publications

(8 citation statements)

References 31 publications

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“…However, egg outlines may differ even when their linear dimensions are identical. Here, we quantify egg shape both with geometric morphometric methods applied to two-dimensional landmarks along the egg outlines [ 9 ], and with traditional morphometric methods applied to linear dimensions. Egg photographs from 11 amniote groups were collated from literature and online sources ( figure 1 ; electronic supplementary material, table S1).…”

Section: Methodsmentioning

confidence: 99%

Egg shape changes at the theropod–bird transition, and a morphometric study of amniote eggs

Deeming¹,

Ruta²

2014

R. Soc. open sci.

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The eggs of amniotes exhibit a remarkable variety of shapes, from spherical to elongate and from symmetrical to asymmetrical. We examine eggshell geometry in a diverse sample of fossil and living amniotes using geometric morphometrics and linear measurements. Our goal is to quantify patterns of morphospace occupation and shape variation in the eggs of recent through to Mesozoic birds (neornithe plus non-neornithe avialans), as well as in eggs attributed to non-avialan theropods. In most amniotes, eggs show significant deviation from sphericity, but departure from symmetry around the equatorial axis is mostly confined to theropods and birds. Mesozoic bird eggs differ significantly from extant bird eggs, but extinct Cenozoic bird eggs do not. This suggests that the range of egg shapes in extant birds had already been attained in the Cenozoic. We conclude with a discussion of possible biological factors imparting variation to egg shapes during their formation in the oviduct.

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Section: Methodsmentioning

confidence: 99%

Egg shape changes at the theropod–bird transition, and a morphometric study of amniote eggs

Deeming¹,

Ruta²

2014

R. Soc. open sci.

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“…Partial warp scores were aligned for every individual as variables, adding the largest warp score (positive or negative) from each variable to make all values positive. The resulting file was input into Primer 6 (Clarke, 1993;Clarke & Gorley, 2006) for subsequent analyses based on Murray, Piller, Merchant, Cooper and Easter (2013). Individuals were averaged over by locality (i.e.…”

Section: Body Shape Variationmentioning

confidence: 99%

Objectively measuring subjectively described traits: geographic variation in body shape and caudal coloration pattern within Vieja melanura (Teleostei: Cichlidae)

McMahan

Kutz

Murray

et al. 2017

RBT

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Vieja melanura is a Neotropical cichlid occurring in the Petén-lake district systems of Guatemala, as well as the Río Grijalva-Usumacinta basin, and other systems in Southern México, Belize, and Guatemala. A caudal stripe, extending forward from the caudal peduncle, is characteristic of this species. This stripe is sloped downward in nearly all individuals of V. melanura, but the degree of the slope is highly variable throughout its range. The slope and shape of the stripe has previously been used in diagnosing and differentiating between species of Vieja. The purpose of this study was to use objective methods to investigate morphological variation in the caudal stripe and body shape throughout the range of V. melanura. We studied geometric morphometric analyses of body shape and empirical measurements of the slope of the caudal stripe in 215 specimens of V. melanura. We also used the mitochondrial cytochrome b marker to study population level patterns within V. melanura. Results from our analyses showed significant geographic variation in body shape and patterns of coloration with little mitochondrial phylogeographic structure. These patterns likely correspond to differences in riverine habitats throughout the species’ distribution. In conclusion, these results can be used to inform other studies of color and shape variation as it applies to taxonomy and systematics.

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“…In the beginning of this century, egg curvature patterns remained as objects of discussion (Möller, 2009;Francevich, 2010;Nishiyama, 2010). Some authors tried to concentrate on limited species (Murray et al, 2013;Avila, 2014;Mieszkalski, 2014), while others present the results obtained from a large number of species (Deeming & Ruta, 2014;Nedomová & Buchar, 2014;Stoddard et al, 2017). The method of photographic analysis was elaborated and presented in Mytiai & Matsyura (2017, 2018, Deeming (2018), and Biggins et al (2018).…”

Section: Introductionmentioning

confidence: 99%

Mathematical interpretation of artificial ovoids and avian egg shapes (part I)

Mytiai

Matsyura

2019

Regul. Mech. Biosyst.

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We performed comparative analysis of curvature characteristics of bird eggs and used ovoid profiles from various authors, our own geometric profiles, and archive bird egg profiles from our database. We suggested that the possible ovoids arise by changing the curvature radii of the polar and lateral zones. We compared the constructed curves and curves presented in oological literature with the pictures of the real bird egg profiles. The volume of actual material includes 16,490 eggs from 800 species of 20 bird orders. Specially designed computer software had calculated the radius of curvature of real bird eggs from photos and drew out the half-profiles presented in our article. We supposed that the asymmetrical ovoid is the most widespread geometric egg-shaped figure, which can easily be obtained by combination of circles. We also calculated that if the ovoid diameter were taken as a unit, then the radius obtuse (infundibular) pole would be equal to its half-length, lateral (side arcs) is equal two lengths, and the cloacal arch is 1–√2/2. From this suggestion, we concluded that the length of the ovoid is 2–√2/2 and its cloacal radius is equal to the difference between the length of ovoid and its diameter (rc = L–D). We analyzed the geometry of this asymmetrical oval and came to the conclusion that this is the basic form able to generate the derivative forms. We discovered that the centres of the arcs which form it lie on one basic/supporting circle, the diameter of which is equal to the ovoid diameter. All other ovoids, which have radius equal to radius of the infundibular zone we called the real ovoids. The changes in the radii of the lateral arcs are caused by the movement of their centres along a horizontal line passing through the centre of the base circle. This causes the prolongation or shortening of the ovoids. Sizes of cloacal arcs depended on the lateral, and their centres are placed along the vertical axis. Variability of the sizes of the abovementioned arcs caused the variability of form of the bird eggs. For their classification, we have proposed to divide them into five groups: sphere-like, circle, obtuse, droplet, and cone-shaped. Further, we separated some more groups: short, shortened, normal, lengthened, and long; according to the sizes of cloacal arcs – large radius, middle radius, and small radius ovoids. As a result, we have 80 forms of real ovoids – standards which describe the varieties of bird eggs. Each of them has its own number, name, geometrical figure, polynomic equation, and correlations of ovoid parameters. This set of ovoids is sufficient to describe the specifics of any form of bird eggs.

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Salinity and Egg Shape Variation: A Geometric Morphometric Analysis

Cited by 7 publications

References 31 publications

Egg shape changes at the theropod–bird transition, and a morphometric study of amniote eggs

Egg shape changes at the theropod–bird transition, and a morphometric study of amniote eggs

Objectively measuring subjectively described traits: geographic variation in body shape and caudal coloration pattern within Vieja melanura (Teleostei: Cichlidae)

Mathematical interpretation of artificial ovoids and avian egg shapes (part I)

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