New! Sign up for our free email newsletter.
Science News
from research organizations

The peculiar cranial anatomy of howler monkeys

New analysis with geometric models published

Date:
December 14, 2017
Source:
CENIEH
Summary:
A new study analyzes the peculiar cranial structure and variability of the best-known species of South American howler monkey, Alouatta seniculus, using geometric models in three dimensions and multivariate statistics.
Share:
FULL STORY

Emiliano Bruner, of the Paleoneurobiology Group of the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), has just published an article in the American Journal of Primatology, which analyzes, for the first time, the peculiar cranial structure and variability of the best-known species of South American howler monkey, Alouatta seniculus, using geometric models in three dimensions and multivariate statistics.

Howler monkeys, which are among the largest primates in Central and South America, have a very peculiar cranial structure, with a highly flexed face which projects forward, a low vault, limited cerebral volume and a brain with few convolutions.

They also carry their head in front of their shoulders, unlike almost all other primates which have it more above the body; they have a very pronounced mandible, associated to major masticatory muscles, a diet based on leaves, and large vocal sacs which characterize their "howls," which are essential for social relationships.

According to the results of the study, at an anatomical level, the variations in the face and vault are not independent, but rather integrated together, following patterns influenced basically by the size of the cranium, the limited development of the vault might be one of the main causes of these modifications, which then involve the architecture of the face secondarily.

"The height of the vault might also influence the pattern of formation of the bones of the side wall of the cranium, which is different in this primate from all other South American monkeys. And the differences between males and females appear to be due only to the size," says Emiliano Bruner.

This work, carried out jointly with Luca Fiorenza, lecturer in human anatomy and evolution at Monash University, in Melbourne (Australia), was financed by the Italian Institute of Anthropology.


Story Source:

Materials provided by CENIEH. Note: Content may be edited for style and length.


Journal Reference:

  1. Luca Fiorenza, Emiliano Bruner. Cranial shape variation in adult howler monkeys (Alouatta seniculus). American Journal of Primatology, 2017; e22729 DOI: 10.1002/ajp.22729

Cite This Page:

CENIEH. "The peculiar cranial anatomy of howler monkeys." ScienceDaily. ScienceDaily, 14 December 2017. <www.sciencedaily.com/releases/2017/12/171214141806.htm>.
CENIEH. (2017, December 14). The peculiar cranial anatomy of howler monkeys. ScienceDaily. Retrieved May 23, 2024 from www.sciencedaily.com/releases/2017/12/171214141806.htm
CENIEH. "The peculiar cranial anatomy of howler monkeys." ScienceDaily. www.sciencedaily.com/releases/2017/12/171214141806.htm (accessed May 23, 2024).

Explore More

from ScienceDaily

RELATED STORIES