Samuel Oluwale Michael, Igado Olumayowa Olawumi
Department of Veterinary Anatomy, Federal University of Agriculture Makurdi, Makurdi, Benue State, Nigeria.
Department of Veterinary Anatomy, University of Ibadan, Ibadan, Nigeria.
BMC Ecol Evol. 2025 May 21;25(1):50. doi: 10.1186/s12862-025-02381-z.
We here present developmental, neurological and evolutionary perspective study of the foramen magnum (FM) and its phylogenetic consequences among five species with close phylogenic proximity. The forms and outlines of this structure emphasize anatomy, physiology, pathology, neurology and evolution demonstrating its immense forensic value. This investigation utilized Elliptical major and minor descriptors in a summary of 26 T. brachyptera, C. familiarius, 26 E. helvum, 20 P. tricuspis and 23 A. albiventris FM outlines in caudal view. Effective Principal Components were the first 6-10 respectively and confirmed size as overrode shape. Fit index of original vs reconstructed values with 92%, 96%, 96%, 97% and 98% accuracies confirmed existing evolutionary order. Irrespective of species, the 3rd harmonic demonstrated maximum values of descriptors but the first yielded highest in elliptical magnitude; E. helvum and T. brachyptera were exceptionally erratic revealing FM architectural complexities in them. Elliptical anisotropy was lowest in A. albiventris and highest in E. helvum with profound amplitude related descriptor values factor reduction between 1/4870 and 1/49 fraction. Partial Least Square and correlation analyses were 100% and 91.86% in combined dataset. Parsimony analysis indicated that Canis familiaris displayed the highest variation in FM evolution, suggesting a greater likelihood of malformation at the root branch of its phylogeny while T. brachyptera was least and more closely related to other species; NJ lead joiner with minimum branch length was P. tricuspis while sub tree and closest sub-tree pairs were A. albiventris and E. helvum respectively. Our results confirmed similar developmental trajectory of the foramen magnum among the species and followed established phylogenetic order but influenced by constraints in C. familiaris. Malformation manifestation possibilities increased along both domestication and phylogenetic levels confirming evolutionary trend and pattern in FM construction among species understudied.
我们在此展示了对枕骨大孔（FM）的发育、神经学和进化视角的研究，以及它在五个系统发育关系密切的物种之间的系统发育结果。这个结构的形态和轮廓强调了解剖学、生理学、病理学、神经学和进化，显示出其巨大的法医价值。本研究使用椭圆的长轴和短轴描述符，总结了26只短翅黑蝇、26只家犬、26只黄腹果蝠、20只三尖叶猴和23只白腹长尾猴的枕骨大孔在尾视图中的轮廓。有效的主成分分别是前6 - 10个，证实了大小比形状更为重要。原始值与重建值的拟合指数分别为92%、96%、96%、97%和98%，证实了现有的进化顺序。无论物种如何，第三次谐波显示描述符的最大值，但第一次谐波在椭圆幅度上产生的最高值；黄腹果蝠和短翅黑蝇异常不稳定，揭示了它们枕骨大孔结构的复杂性。椭圆各向异性在白腹长尾猴中最低，在黄腹果蝠中最高，相关描述符值的幅度因子在1/4870至1/49之间显著降低。在组合数据集中，偏最小二乘法和相关性分析分别为100%和91.86%。简约分析表明，家犬在枕骨大孔进化中表现出最高的变异性，表明其系统发育根部出现畸形的可能性更大，而短翅黑蝇的变异性最小，与其他物种的关系更密切；分支长度最短的NJ引导连接法是三尖叶猴，而子树和最接近的子树对分别是白腹长尾猴和黄腹果蝠。我们的结果证实了这些物种中枕骨大孔有相似的发育轨迹，并遵循既定的系统发育顺序，但受到家犬的限制影响。沿着驯化和系统发育水平，畸形表现的可能性增加，证实了所研究物种中枕骨大孔结构的进化趋势和模式。
