Editorial Type:
Article Category: Research Article
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Online Publication Date: 17 Jul 2023

Morphometric Variability in Lizards of the Genus Teius: A Comparative Study of Species with Different Reproductive Modes

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Page Range: 238 – 245
DOI: 10.1670/21-044
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ABSTRACT

The lizard genus Teius is widely distributed in lowland areas to the east of the Andes in southern South America and includes three species: Teius teyou, T. oculatus, and T. suquiensis. All three Teius species are broadly similar in morphological characters, the dorsal coloration pattern being the best feature to distinguish them. Furthermore, T. suquiensis are parthenogenetic, whereas the other two are bisexual. We applied 2D geometric morphometric methods on head morphology to measure and compare variability between these clonally and sexually reproductive lizards and to assess form variability among populations within the parthenogenetic species. We studied 181 adult females of the three species from across a wide range of their distributions. Geometric morphometrics successfully separated them in the morphospace. The three Teius presented similar head size; hence, the differences found are related to shape. Teius teyou has a shorter snout and a narrower posterior area of the head whereas T. oculatus has a longer snout and a wider posterior area of the head, and T. suquiensis shows an intermediate phenotype. Levels of morphological variability among the species were similar and independent of reproductive mode. Differences in head size and shape among populations were observed within T. suquiensis, despite its clonal inheritance. The observed variability might be explained by populations that are composed of different clonal lineages, populations that showed different responses to varying local environmental factors, or both. Additional morphological studies considering genetic diversity and habitat characteristics may clarify the factors that promote morphological variability in the genus, especially in the parthenogenetic species.

Copyright: Copyright 2023 Society for the Study of Amphibians and Reptiles 2023
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Fig. 1.
Fig. 1.

Maps showing: (A) collecting localities of Teius, stars indicate T. teyou, squares T. oculatus and circles T. suquiensis, (B) sampling area in Argentina, South America, and (C) collecting localities represented by the letters “a–e” of T. suquiensis selected for intraspecific variability analysis.

Fig. 2.
Fig. 2.

Landmark configuration defined on the head of Teius lizards. Scale references: R, rostral; N, nasal; FN, frontonasal; PF, prefrontal; F, frontal; FP, frontoparietal; IP, interparietal; PA parietal; SU, supraocular; PN, postnasal. Numbers identify the position of each landmark recorded on the head, as specified in Table 1. White and black dots indicate type 1 landmarks, whereas gray and black dots indicate type 2 landmarks.

Fig. 3.
Fig. 3.

Boxplot of centroid size (CS) of the head of the Teius species. Asterisks correspond to outlier specimens.

Fig. 4.
Fig. 4.

Scatterplot of the first two principal components (PC1 vs. PC2) showing positions of Teius individuals in the morphospace and the percentage of total variance explained by each PC. The first PC axis explains changes of the relative length of the head in the anteroposterior direction, while the second PC axis is mainly associated with the relative width of the head.

Fig. 5.
Fig. 5.

Species-specific standard deviation in T. teyou, T. oculatus, and T. suquiensis for the first two components of the PCA. Letters “a,” “ab,” and “b” indicate significant differences (P < 0.05) in the standard deviation among the three species for the first component, while the letter “c” indicates no significant difference for the second component.

Fig. 6.
Fig. 6.

Scatterplot of the first two canonical variate functions among Teius species and the percentage of variance among groups explained by each CV. Ellipses represent 90% confidence for each species.

Fig. 7.
Fig. 7.

Deformation grids for the first canonical variate (CV1) for mean shape (black line) of (A) T. teyou, (B) T. oculatus, and (C) T. suquiensis. The gray line corresponds to the consensus configuration. Numbers indicate landmark positions and capital letters represent scales, both listed in Table 1.

Fig. 8.
Fig. 8.

Deformation grids for the second canonical variate (CV2) for mean shape (black line) of (A) T. teyou, (B) T. oculatus, and (C) T. suquiensis. The gray line corresponds to the consensus configuration. Numbers indicate landmark positions and capital letters represent scales, both listed in Table 1.

Fig. 9.
Fig. 9.

Scatterplot of the first two principal components (PC1 vs. PC2) showing position of Teius suquiensis individuals in the morphospace and the percentage of total variance explained by each PC. The displayed deformation grids for the positive and negative extremes of each PC illustrate corresponding patterns. Letters “a–e” represent the five collecting localities. Numbers indicate landmark positions and capital letters represent scales, both listed in Table 1.

Fig. 10.
Fig. 10.

Scatterplot of the first two canonical variate functions among populations of Teius suquiensis and the percentage of variance among groups explained by each CV. Ellipses represent 90% confidence for each population. The letters “a–e” represent the five collecting localities.

Contributor Notes

3 Corresponding author: E-mail: barbaraespeche@gmail.com
Accepted: 16 Dec 2022
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