Navigation Links
New study changes conceptions about the determinants of skull development and form

A new study by a team of researchers led by Matthew Ravosa, professor of biological sciences and concurrent professor of aerospace and mechanical engineering and anthropology at the University of Notre Dame, offers surprising insights into dietary influences on the growing skull.

Ravosa notes that the robust jaws and large, thick-enameled molars of the first human ancestors from Africa, known as australopiths, have longbeen interpreted as adaptations for hard object feeding, especially in the genus Paranthropous robustus, and to a lesser extent, Australopithecus.

Recent studies of molar surface microware indicate that only Paranthropous robustus regularly ate hard items, suggesting that the oral anatomy of other australopiths reflected rare, seasonal exploitations of hard fallback foods. Fallback foods are typically more mechanically challenging than diets exploited on a more annual basis are critical to survive seasonal periods when easier to process preferred resources are scarce. The ecological and morphological importance of fallback foods have been implicated in a number of recent studies of living and fossil mammals.

"In contrast to this highly influential hypothesis about australopith feeding adaptations, our study demonstrated that hard object feeding cannot explain the extreme morphology of Paranthropous boisei," Ravosa said. "Rather, analysis of long-term dietary plasticity in an animal model, in this case rabbits, suggests year-round reliance on tough foods requiring prolonged post-canine processing in Paranthropous boisei. Increased consumption of such food items may have marked the transition from the earlier hominids Ardipithecus to Australopithecus, with routine hard object feeding in Paranthropous robustus representing a novel behavior."

The researchers used a sample which contained 30 five-week-old weanling male rabbits divided equally into three dietary cohorts and raised for 48 weeks.

Prior research in Ravosa's lab has focused on diet-induced plasticity in the skull and feeding complex in in growing rabbits and rodents. These kinds of studies are important for evaluating the functional significance of various craniofacial features, particularly those less accessible via more direct in vivo approaches, as well as for unraveling the feeding behavior of extinct species.

"However, prior to our present investigation, we'd not been able to track dietary influences on the growing skull in the same individual (i.e., longitudinally), we'd not modeled seasonal variation in dietary properties, and we'd not tracked dietary effects for an entire year (i.e., from weaning until middle age)," Ravosa said. "These aspects of our study were novel vs. all other such work (in our lab and elsewhere) and facilitated a more naturalistic perspective on ecological determinants of postnatal and evolutionary changes in mammalian skull form. By being able to track the extent to which morphological changes in the cranium track (or do not track) dietary changes, we were also able to evaluate the extent to which skeletal structure can be used to infer behavior in the fossil record, a common assumption that surprisingly is largely untested.

"While my lab has long focused on functional determinants of phenotypic variation in skull form in primate and non-primate mammals, it has rarely focused on human evolution. However, as the notion that seasonal variation in the presence of hard/tough diets explains the robust jaws and teeth of early human ancestors (australopiths) has become widely accepted, our rabbit study is of particularly unique relevance for addressing such outstanding questions."

Ravosa was the principal investigator for the study and the research team included postdoctoral fellow Jeremiah Scott, now a faculty member at Southern Illinois University, senior research technician Kevin McAbee, and former Notre Dame undergraduate researcher Meghan Eastman. The study appears in the journal Biology Letters.


Contact: Matthew Ravosa
University of Notre Dame

Related biology news :

1. Study by UC Santa Barbara researchers suggests that bacteria communicate by touch
2. Law that regulates shark fishery is too liberal: UBC study
3. New study will help protect vulnerable birds from impacts of climate change
4. Study jointly led by UCSB researcher supports theory of extraterrestrial impact
5. BYU study: Using a gun in bear encounters doesnt make you safer
6. 15-year study: When it comes to creating wetlands, Mother Nature is in charge
7. Pycnogenol (French maritime pine bark extract) shown to improve menopause symptoms in new study
8. Crystal structure of archael chromatin clarified in new study
9. EU-funded study underlines importance of Congo Basin for global climate and biodiversity
10. University of Houston study shows BP oil spill hurt marshes, but recovery possible
11. Study demonstrates cells can acquire new functions through transcriptional regulatory network
Post Your Comments:
(Date:10/29/2015)... RESTON, Va. , Oct. 29, 2015 ... announced today that it has released a new version ... Daon customers in North America ... gains. IdentityX v4.0 also includes a FIDO UAF ... customers are already preparing to activate FIDO features. These ...
(Date:10/29/2015)... Connecticut , October 29, 2015 ... a biometric authentication company focused on the growing ... smart wallet announces that StackCommerce, a leading marketplace ... be featuring the Wocket® smart wallet on StackSocial ... NXTD ) ("NXT-ID" or the "Company"), a biometric ...
(Date:10/27/2015)... Germany , October 27, 2015 ... SMI,s Automated Semantic Gaze Mapping technology (ASGM) automatically maps ... SMI,s Eye Tracking Glasses , so that they ... BeGaze. --> Munich, Germany , ... (ASGM) automatically maps data from mobile eye tracking videos ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... Nov. 24, 2015 HemoShear Therapeutics, LLC, ... drugs for metabolic disorders, announced today the appointment ... Board of Directors (BOD). Mr. Watkins is the ... Genome Sciences (HGS), and also served as the ... Jim Powers , Chairman and CEO of HemoShear ...
(Date:11/24/2015)... MUNICH and NEW YORK , ... irst investment by Bristol-Myers Squibb in a ... Bristol-Myers Squibb Company in which the companies ... products in immuno-oncology and other areas of unmet medical need. ... Squibb in LSP 5, the latest LSP fund. This is ...
(Date:11/24/2015)... Nov. 24, 2015 According to two new studies, ... This is something that many doctors, scientists, and public health ... remains: with fewer PSA tests being done, will there be ... Dr. David Samadi, "Despite the efforts made in ... the second leading cancer cause of death in men, killing ...
(Date:11/23/2015)... --  Ceres, Inc . (Nasdaq: CERE ), an ... fiscal year ended August 31, 2015 and provided an ... --> During fiscal year 2015, Ceres refocused ... a better balance of yield, energy and nutrition. Among ... leading crop input providers and made significant progress in ...
Breaking Biology Technology: