Probable developmental, neurological and evolutionary trend in complex morphological structures: foramen magnum outlines analytic comparisons in four orders; Chiroptera: (Eidolon helvum), (Tadarida brachyptera), Pholidota (Phataginus tricuspis), Eulipotyphla (Atelerix albiventris) and Carnivora (Canis familiaris).

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.