to detect bilateral and bisexual variations in endocranial suture closure if any, to specify the relationship between progression of union of endocranial suture and age of the subject to formulate a practical method of estimation of age by studying the progression of the closure of cranial sutures.
Degree of closure was scored in 16 parts of the main cranial sutures as done by Acsadi-Nemeskeri.
Cranial suture closure, its progress and age relationship part 2 ectocranial closure in adult males of white stock.
Cranial suture closure, its progress and age relationship part 3 endocranial closure in adult males of negro stock.
A similar outcome has been presented by Pinedo (1991), who found that fusion of most cranial sutures was weakly correlated with age groups, and that invisibility of the SQ-PR suture, together with some discrete morphological characters of the skull (i.
2011), detected that bigger species of porpoises (Phocoenoides dalli, Phocoena dipotrica) generally show further development of cranial sutures than smaller species (Phocoena phocoena, P spinipinnis), also supporting the hypothesis of Barman et al.
Further comparisons in a phylogenetic context could shed light on heterochronic process or paedomorphic condition occurred during the evolution of P blainvillei, considering their limited fusion of cranial sutures detected here.
Summarizing, our results indicate that P blainvillei cranial sutures have low variability in relation to body size and do not show directional asymmetry on their closure.
The degree of closure of the cranial sutures
indicates a mean age of 40 (interdecile range of 28 to 51).
Therefore, the most suitable methods for determining age categories in field-trapped geomyids have been those based on the closure of the cranial sutures
(Thaeler, 1967; Hoffmeister, 1969), especially of the basisphenoid suture.
Unlike more prominent traits such as skull breadth, these features -- including tiny bones formed by cranial sutures
and small bridges of bone caused by excess growth -- confer few survival advantages and mainly evolve randomly, outside the influence of behavioral adaptations to a particular environment, Pardoe contends.
INTRODUCTION: Wormian bones are accessory bone which occurs within the cranial sutures