Gurgis George P, Daza Juan D, Brennan Ian G, Hutchinson Mark, Bauer Aaron M, Stocker Michelle R, Olori Jennifer C
Department of Biological Sciences, State University of New York at Oswego, Oswego, NY, USA.
Deparment of Biological Sciences, Sam Houston State University, Huntsville, TX, USA.
Integr Org Biol. 2021 Apr 22;3(1):obab013. doi: 10.1093/iob/obab013. eCollection 2021.
Pygopodids are elongate, functionally limbless geckos found throughout Australia. The clade presents low taxonomic diversity (∼45 spp.), but a variety of cranial morphologies, habitat use, and locomotor abilities that vary between and within genera. In order to assess potential relationships between cranial morphology and ecology, computed tomography scans of 29 species were used for 3D geometric morphometric analysis. A combination of 24 static landmarks and 20 sliding semi-landmarks were subjected to Generalized Procrustes Alignment. Disparity in cranial shape was visualized through Principal Component Analysis, and a multivariate analysis of variance (MANOVA) was used to test for an association between shape, habitat, and diet. A subset of 27 species with well-resolved phylogenetic relationships was used to generate a phylomorphospace and conduct phylogeny-corrected MANOVA. Similar analyses were done solely on taxa to explore species-level variation. Most of the variation across pygopodids was described by principal component (PC) 1(54%: cranial roof width, parabasisphenoid, and occipital length), PC2 (12%: snout elongation and braincase width), and PC3 (6%: elongation and shape of the palate and rostrum). Without phylogenetic correction, both habitat and diet were significant influencers of variation in cranial morphology. However, in the phylogeny-corrected MANOVA, habitat remained weakly significant, but not diet, which can be explained by generic-level differences in ecology rather than among species. Our results demonstrate that at higher levels, phylogeny has a strong effect on morphology, but that influence may be due to small sample size when comparing genera. However, because some closely related taxa occupy distant regions of morphospace, diverging diets, and use of fossorial habitats may contribute to variation seen in these geckos.
鳞脚蜥是一种身体细长、功能上无肢的壁虎，分布于澳大利亚各地。该类群的分类多样性较低（约45种），但具有多种颅骨形态、栖息地利用方式和运动能力，这些在属与属之间以及属内都有所不同。为了评估颅骨形态与生态之间的潜在关系，对29个物种的计算机断层扫描进行了三维几何形态测量分析。对24个静态地标点和20个滑动半地标点进行了广义普氏叠加分析。通过主成分分析可视化颅骨形状的差异，并使用多变量方差分析（MANOVA）来检验形状、栖息地和饮食之间的关联。使用27个具有明确系统发育关系的物种子集来生成系统发育形态空间并进行系统发育校正的MANOVA分析。仅对分类单元进行了类似分析，以探索物种水平的变异。鳞脚蜥的大部分变异由主成分（PC）1（54%：颅顶宽度、基蝶骨和枕骨长度）、PC2（12%：吻部伸长和脑壳宽度）和PC3（6%：腭和吻部的伸长和形状）描述。在没有系统发育校正的情况下,栖息地和饮食都是颅骨形态变异的重要影响因素。然而，在系统发育校正的MANOVA分析中，栖息地仍然具有微弱显著性，但饮食不具有显著性，这可以用生态在属水平而非物种水平上的差异来解释。我们的结果表明，在较高水平上，系统发育对形态有很强的影响，但这种影响可能是由于比较属时样本量较小。然而，由于一些亲缘关系密切分类单元占据了形态空间的不同区域，不同的饮食和对洞穴栖息地的利用可能导致了这些壁虎的形态变异。
