Szara Tomasz, Kamiński Marcin Jan, Gündemir Ozan
Department of Morphological Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, 02-776, Warsaw, Poland.
Zoological Museum, Museum and Institute of Zoology, Polish Academy of Sciences, Twarda 51/55, 00-818, Warszawa, Poland.
Sci Rep. 2025 Jul 2;15(1):22824. doi: 10.1038/s41598-025-05967-1.
Darkling beetles (Tenebrionidae) are a diverse and ecologically significant group, particularly in arid environments, yet their taxonomy remains problematic due to scarcity of phylogenetic contributions and robust morphological investigations. This study applies 3D geometric morphometrics to evaluate the taxonomic validity and morphological differentiation among three closely related sandworm beetle taxa: Gonopus deplanatus, G. tibialis kalaharicus, and G. tibialis punctatus. Seventy-nine museum-preserved specimens were digitized using a 3D scanner, with multiple scans taken from six different orientations to ensure comprehensive surface reconstruction. Twenty-one anatomical landmarks were assigned to the prothorax (12 landmarks) and pterothorax (9 landmarks), targeting significant taxonomic features like pronotal width, elytral curvature, and the structure of the prosternal process. Based on this dataset, the size and shape variation were analyzed. Results suggest that G. t. punctatus displayed a narrower pronotum and more pronounced prosternal process than G. t. kalaharicus and G. deplanatus, indicating a previously underappreciated taxonomic distinction. For elytra, the differences among taxa were primarily observed in width, curvature, and declivity. Additionally, the stronger correlation between pterothorax shape and size suggests that larger individuals tend to have more pronounced and rounded elytra, potentially influencing thermoregulation or structural reinforcement in response to environmental pressures. These results show the transformative potential of 3D geometric morphometrics in entomological systematics by providing a quantitative framework for distinguishing closely related beetle taxa. These findings suggest that traditional taxonomic criteria may have underestimated the extent of variation between these taxa, underscoring the importance of integrating advanced morphometric approaches into systematic studies. Furthermore, detecting allometric influences in shape variation provides new insights into potential functional and ecological adaptations, which may be linked to the distinct desert environments these beetles inhabit.
拟步甲科甲虫是一个种类多样且具有重要生态意义的类群，在干旱环境中尤为如此，但由于系统发育研究和深入的形态学调查匮乏，其分类学仍然存在问题。本研究应用三维几何形态测量学来评估三种近缘沙虫甲虫类群：扁平戈壁甲（Gonopus deplanatus）、卡拉哈里胫戈壁甲（G. tibialis kalaharicus）和点胫戈壁甲（G. tibialis punctatus）之间的分类有效性和形态差异。使用三维扫描仪对79个保存在博物馆的标本进行数字化处理，从六个不同方向进行多次扫描，以确保全面的表面重建。在前胸（12个地标点）和后胸（9个地标点）上指定了21个解剖学地标点，针对显著的分类特征，如前胸宽度、鞘翅曲率和前胸腹板突的结构。基于该数据集，分析了大小和形状变化。结果表明，与卡拉哈里胫戈壁甲和扁平戈壁甲相比，点胫戈壁甲的前胸更窄，前胸腹板突更明显，这表明存在一个此前未被充分认识的分类区别。对于鞘翅，类群之间的差异主要体现在宽度、曲率和倾斜度上。此外，后胸形状和大小之间更强的相关性表明，较大的个体往往具有更明显且圆润的鞘翅，这可能会影响体温调节或应对环境压力时的结构强化。这些结果显示了三维几何形态测量学在昆虫系统学中的变革潜力，为区分近缘甲虫类群提供了一个定量框架。这些发现表明，传统分类标准可能低估了这些类群之间的变异程度，强调了将先进的形态测量方法纳入系统研究的重要性。此外，检测形状变化中的异速生长影响为潜在的功能和生态适应提供了新的见解，这可能与这些甲虫所栖息的独特沙漠环境有关。
