More Like this

1. How mangabey molar form differs under routine vs. fallback hard-object feeding regimes

   https://doi.org/10.7717/peerj.16534  

   Guatelli-Steinberg, Debbie; Renteria, Cameron; Grimm, Jack R.; Maeret Carpenter, Izabela; Arola, Dwayne D.; McGraw, W. Scott (January 2023, PeerJ)

   BackgroundComponents of diet known as fallback foods are argued to be critical in shaping primate dental anatomy. Such foods of low(er) nutritional quality are often non-preferred, mechanically challenging resources that species resort to during ecological crunch periods. An oft-cited example of the importance of dietary fallbacks in shaping primate anatomy is the grey-cheeked mangabeyLophocebus albigena. This species relies upon hard seeds only when softer, preferred resources are not available, a fact which has been linked to its thick dental enamel. Another mangabey species with thick enamel, the sooty mangabeyCercocebus atys, processes a mechanically challenging food year-round. That the two mangabey species are both thickly-enameled suggests that both fallback and routine consumption of hard foods are associated with the same anatomical feature, complicating interpretations of thick enamel in the fossil record. We anticipated that aspects of enamel other than its thickness might differ betweenCercocebus atysandLophocebus albigena.We hypothesized that to function adequately under a dietary regime of routine hard-object feeding, the molars ofCercocebus atyswould be more fracture and wear resistant than those ofLophocebus albigena. MethodsHere we investigated critical fracture loads, nanomechanical properties of enamel, and enamel decussation inCercocebus atysandLophocebus albigena.Molars ofCercopithecus, a genus not associated with hard-object feeding, were included for comparison. Critical loads were estimated using measurements from 2D µCT slices of upper and lower molars. Nanomechanical properties (by nanoindentation) and decussation of enamel prisms (by SEM-imaging) in trigon basins of one upper second molar per taxon were compared. ResultsProtocone and protoconid critical fracture loads were significantly greater inCercocebus atysthanLophocebus albigenaand greater in both than inCercopithecus. Elastic modulus, hardness, and elasticity index in most regions of the crown were greater inCercocebus atysthan in the other two taxa, with the greatest difference in the outer enamel. All taxa had decussated enamel, but that ofCercocebus atysuniquely exhibited a bundle of transversely oriented prisms cervical to the radial enamel. Quantitative comparison of in-plane and out-of-plane prism angles suggests that decussation in trigon basin enamel is more complex inCercocebus atysthan it is in eitherLophocebus albigenaorCercopithecus cephus. These findings suggest thatCercocebus atysmolars are more fracture and wear resistant than those ofLophocebus albigenaandCercopithecus. Recognition of these differences betweenCercocebus atysandLophocebus albigenamolars sharpens our understanding of associations between hard-object feeding and dental anatomy under conditions of routine vs. fallback hard-object feeding and provides a basis for dietary inference in fossil primates, including hominins. 

   more » « less
2. The Platyrrhine Primate Cebus imitator Uses Gaze to Manipulate and Withdraw Food to the Mouth

   https://doi.org/10.26451/abc.11.01.01.2024  

   Whishaw, Ian; Mah, Megan; Casorso, Julia; Chacon, Evin; Chalk-Wilayto, Janine; Laird, Myra; Melin, Amanda (February 2024, Animal Behavior and Cognition)

   Orienting a food item held in the hand to withdraw and optimally place it in the mouth for eating (withdraw-to-eat) is mediated by vision in catarrhine anthropoids and by nonvisual strategies in strepsirrhine primates. The present study asks whether vision contributes to the withdraw-to-eat movements in a platyrrhine anthropoid Cebus imitator, a member of a monophyletic primate suborder whose stem group diverged from catarrhines about 40 million years ago. Cebus imitator’s gaze and hand use for foraging for fruit is examined in its fine branch niche, the terminal branches of trees. Video of reach, grasp and withdraw-to-eat movements with associated gaze were examined frame-by-frame to assess food manipulation and its sensory control. Cebus imitator uses vision and touch to reach for and grasp food items with precision and whole hand grasps. They use vision to orient food items held in-hand into a precision grip and their withdraw-to-eat is assisted with a vertically oriented hand. The conjoint use of vision, a precision grasp, and hand posture and a central representation of object control likely originated in stem anthropoids and was derived from the staged evolution of the visual manipulation of food and other objects. 

   more » « less
3. Fruit and Vegetable Consumption, Food Acquisition Behavior, and Food Insecurity Before and After the COVID-19 Vaccine Rollout

   https://doi.org/10.1097/PHH.0000000000001946  

   Hosler, Akiko S; Chen, Jiacheng; Arroyo, Mariana Torres; Neff, Roni A; Bozlak, Christine T; Romeiko, Xiaobo X; Feingold, Beth J (January 2024, Journal of Public Health Management & Practice)

   Objectives:To assess changes in food acquisition behavior, food insecurity, and dietary behavior and identify factors associated with fruit and vegetable (FV) consumption during the transitional period (before and after the initial vaccine rollout for all adults) of the COVID-19 pandemic. Design:Successive independent samples design. Online surveys were conducted from October 2020 to February 2021 (time 1, before the vaccine rollout) and from October 2021 to December 2021 (time 2, after the vaccine rollout). Descriptive analysis examined changes in food sources, food security, and daily FV consumption in cup equivalents (CEs) from time 1 to time 2. A multivariable logistic regression analysis examined factors associated with FV consumption. Setting:The Capital Region of New York State. Participants:1553 adults 18 years of age and older. Main Outcome Measure:Meeting the 2020-2025 MyPlate daily FV consumption recommendations. Results:There were statistically significant (P< .05) increases in the use of supermarkets, eat-in restaurants, farmers’ markets, and convenience stores from time 1 to time 2. Food insecurity (40.1% vs 39.4%) and FV consumption (2.6 CE vs 2.4 CE) slightly declined but not significantly. Home food procurement such as gardening and foraging (OR, 1.61; 95% CI, 1.08-2.37) and shopping at food co-op/health food stores (OR, 1.64; 95% CI, 1.07-2.49) were significantly associated with the FV outcome, and these relationships were not modified by food security status. Conclusions:The present study highlights the importance of food sources in understanding adult dietary behavior during the transitional period of the pandemic. Continuing efforts to monitor access to food sources, food insecurity, and dietary behavior are warranted as various COVID-related emergency food assistance measures have expired. 

   more » « less
4. Dental sculpting and compensatory shearing crests demonstrated in a Wear series of Presbytis rubicunda (Cercopithecoidea, Colobidae) with dental topography analysis

   https://doi.org/10.1002/ajpa.24953  

   Pampush, James D.; Morse, Paul E.; Kay, Richard F. (May 2024, American Journal of Biological Anthropology)

   Abstract ObjectivesMaintaining effective and efficient occlusal morphology presents adaptive challenges for mammals, particularly because mastication produces interactions with foods and other materials that alters the geometry of occlusal surfaces through macrowear and/or catastrophic failure (i.e. “chipping”). Altered occlusal morphologies are often less effective for masticating materials of given diet—but not always—some species exhibit dental sculpting, meaning their dentitions are set up to harness macrowear to hone their occlusal surfaces into more effective morphologies (i.e. secondary morphologies). Here we show that dental sculpting is present in the folivorousPresbytis rubicundaof Borneo. MethodsThirty‐one undamaged lower second molars ofP.rubicundaexhibiting various stages of macroscopic wear were micro‐CT scanned and processed into digital surfaces. The surfaces were measured for convex Dirichlet normal energy (vDNE, a measure of surface sharpness), and degree of surface wear. Regression analyses compared surface sharpness with several measures of wear to test for the presence and magnitude of dental sculpting. ResultsPositive correlations between the wear proxies and vDNE reveal thatP.rubicundawear in such a way as to become sharper, and therefore more effective chewing surfaces by exposing enamel‐dentine junctions on their occlusal surfaces and then honing these junctions into sharpened edges. Compared to another primate folivore in which increasing surface sharpness with macrowear has been demonstrated (i.e.,Alouatta palliata), the worn surfaces are similarly sharp, but the dental sculpting process appears to be different. DiscussionThe results presented here suggest that not only do some primates exhibit dental sculpting and the attendant secondary morphology, but that there appear to be multiple different morphological configurations that can achieve this result.P.rubicundahas thicker enamel and a more stereotyped wear pattern thanA.palliata, although both show positive correlations of occlusal surface sharpness (vDNE) with various wear proxies. These findings shed light on the varied approaches for the maintenance of effective and efficient occlusal surfaces in primates. 

   more » « less
5. Quantifying occlusal wear in extant and fossil primates: A novel approach using the virtual goniometer for wear and dietary analysis

   Lama-Luther, R; O'Neill, R (March 2025, American Journal of Biological Anthropology)

   Turner, T (Ed.)

   Advancements in 3D scanning and modeling have transformed dental and dietary analyses, yet studies often focus on whole-crown, unworn teeth, limiting sample sizes and scope due to the challenges of analyzing worn teeth. Here we explore a novel quantitative method using a virtual goniometer to measure occlusal wear angles in over 150 worn mandibular second molars from extant primates, including frugivores, folivores, and hard-object consumers. For the first time, we apply this method to fossil primates: Ekembo, Dendropithecus, and Limnopithecus. Using the Hecate software package, we align and subdivide molars into five patches corre- sponding to the cusps. We segment each patch using the virtual goniometer. This segments the occlusal surface from the corresponding buccal, lingual, mesial, and distal surfaces, providing a normal vector corresponding to the plane of best fit for each segment. We then calculate three key angles that describe the plane orientation. Results suggest the inclination measurement from the virtual goniometer is more robust than the average inclination of points in the occlusal surface. Additionally, we find that, among the fossil sample, wear across cusps does not align with any of the tested extant dietary categories. Paleontology is a versatile field of study, applying methods used across disciplines. Our novel approach provides yet another example in which paleontology makes use of versatile computer application by extending the virtual goniometer’s utility beyond archaeological inquiries to primate dental analysis. Additionally, this application offers valuable insight into evolutionary traits associated with dietary behaviors through the inclusion of extant and fossil primates. 

   more » « less