Taewcharoen Nuttakorn, Norris Rachel, Sherratt Emma
School of Biological Sciences The University of Adelaide Adelaide South Australia Australia.
School of Animal and Veterinary Sciences The University of Adelaide Roseworthy South Australia Australia.
Ecol Evol. 2024 Jun 4;14(6):e11478. doi: 10.1002/ece3.11478. eCollection 2024 Jun.
During mammalian terrestrial locomotion, body flexibility facilitated by the vertebral column is expected to be correlated with observed modes of locomotion, known as gait (e.g., sprawl, trot, hop, bound, gallop). In small- to medium-sized mammals (average weight up to 5 kg), the relationship between locomotive mode and vertebral morphology is largely unexplored. Here we studied the vertebral column from 46 small- to medium-sized mammals. Nine vertebrae across cervical, thoracic, and lumbar regions were chosen to represent the whole vertebral column. Vertebra shape was analysed using three-dimensional geometric morphometrics with the phylogenetic comparative method. We also applied the multi-block method, which can consider all vertebrae as a single structure for analysis. We calculated morphological disparity, phylogenetic signal, and evaluated the effects of allometry and gait on vertebral shape. We also investigated the pattern of integration in the column. We found the cervical vertebrae show the highest degree of morphological disparity, and the first thoracic vertebra shows the highest phylogenetic signal. A significant effect of gait type on vertebrae shape was found, with the lumbar vertebrae having the strongest correlation; but this effect was not significant after taking phylogeny into account. On the other hand, allometry has a significant effect on all vertebrae regardless of the contribution from phylogeny. The regions showed differing degrees of integration, with cervical vertebrae most strongly correlated. With these results, we have revealed novel information that cannot be captured from study of a single vertebra alone: although the lumbar vertebrae are the most correlated with gait, the cervical vertebrae are more morphologically diverse and drive the diversity among species when considering whole column shape.
在哺乳动物的陆地运动过程中，由脊柱促成的身体灵活性预计与所观察到的运动模式相关，这种运动模式被称为步态（例如， sprawl、trot、hop、bound、gallop）。在中小型哺乳动物（平均体重达5千克）中，运动模式与脊椎形态之间的关系在很大程度上尚未得到探索。在此，我们研究了46种中小型哺乳动物的脊柱。选取了颈椎、胸椎和腰椎区域的九块椎骨来代表整个脊柱。使用三维几何形态测量学和系统发育比较方法对椎骨形状进行分析。我们还应用了多块法，该方法可将所有椎骨视为一个单一结构进行分析。我们计算了形态差异、系统发育信号，并评估了异速生长和步态对椎骨形状的影响。我们还研究了脊柱中的整合模式。我们发现颈椎显示出最高程度的形态差异，第一胸椎显示出最高的系统发育信号。发现步态类型对椎骨形状有显著影响，其中腰椎的相关性最强；但在考虑系统发育后，这种影响并不显著。另一方面，无论系统发育的贡献如何，异速生长对所有椎骨都有显著影响。不同区域显示出不同程度的整合，颈椎之间的相关性最强。基于这些结果，我们揭示了仅从单个椎骨研究中无法获得的新信息：尽管腰椎与步态的相关性最强，但在考虑整个脊柱形状时，颈椎在形态上更加多样，并驱动了物种间的多样性。
