Using digital images in the study of fluctuating asymmetry in the spur-thighed tortoise Testudo graeca

Abstract

Fluctuating asymmetry has been proposed as a useful noninvasive tool for detecting the influence of the environment on body development. In the present study, we used digital images to estimate the fluctuating asymmetry of the plastron in an isolated Testudo graeca population in Dobrogea, Romania. We extracted data from the photos regarding the area, height, and width of 3 plastron scutes. A total of 155 adult tortoises analysed showed reduced variation in plastron asymmetry and no significant relationship was detected between fluctuating asymmetry and sex or body size. We suggest that fluctuating asymmetry may be an individual trait, with no predictive value at the population level.

Morphometric geometric differences between right and left human tali: A cadaveric study of fluctuating asymmetry via systematic measurement and three-dimensional scanning

“…Direct combination of these measurement methods revealed morphologic variations in contrast to the findings by Islam et al The right and left tali demonstrated several differences in terms of their morphometric profiles. These deviations from bilateral symmetry may exceed the body's ability to maintain its usual development in stressful conditions [8,9]. Regarding the stressful condition, Julius Wolff and others realized that mechanical loads can affect bone architecture in living beings [19].…”

“…The present study was performed to demonstrate the morphometric geometric variations between the right and left tali in matched pairs of human cadaveric specimens. The authors hypothesized that fluctuating asymmetry [8] [9] involving morphometric geometric differences exists between the bilateral tali and that this asymmetry may alter the current method used to manufacture templates from the normal contralateral talus.…”

Scutation asymmetries in red-footed tortoise Chelonoidis carbonaria Spix, 1824 (Testudines: Testudinidae)

“…In a typical case, scale cover mosaic of turtles (pholidosis) is arranged in longitudinal rows with strict bilateral symmetry (Cherepanov, 2014). But while the shell as an overall structure is under selection, specific landmarks on the shell (such as the location of scute sutures), may be under less direct selection (Băncilă et al, 2012;Buică & Cogălniceanu, 2013;Cherepanov, 2014). To date, available studies of scale asymmetries are scarce and sometimes with contradictory conclusions.…”

“…Chelonoidis carbonaria is a species from South America, distributed from northern Paraguay and Argentina through cis-Andean South America to Panama (Gallego-García et al, 2015;Cacciali et al, 2016;Turtle Taxonomy Working Group, 2017). These medium-sized tortoises generally average 30 cm as adults, but can reach over 40 cm (Barros et al, 2012). They have dark-colored, loaf-shaped carapaces (back shell) with a lighter patch in the middle of each scute, and dark limbs with brightly colored scales that range from pale yellow to dark red, although with a great variation in this morphological characteristic (Barros et al, 2012) (Gallego-García et al, 2015.…”

“…These medium-sized tortoises generally average 30 cm as adults, but can reach over 40 cm (Barros et al, 2012). They have dark-colored, loaf-shaped carapaces (back shell) with a lighter patch in the middle of each scute, and dark limbs with brightly colored scales that range from pale yellow to dark red, although with a great variation in this morphological characteristic (Barros et al, 2012) (Gallego-García et al, 2015. No sex dimorphism is observed concerning size (Barros et al, 2012), but population differences are recognized between different regions (Barros et al, 2012).…”