More Like this

1. Phylogenetic and environmental effects on limb bone structure in gorillas

   https://doi.org/10.1002/ajpa.23437  

   Ruff, Christopher B. ; Burgess, M. Loring ; Junno, Juho‐Antti ; Mudakikwa, Antoine ; Zollikofer, Christophe P. E. ; Ponce de León, Marcia S. ; McFarlin, Shannon C. ( February 2018 , American Journal of Physical Anthropology)

   The effects of phylogeny and locomotor behavior on long bone structural proportions are assessed through comparisons between adult and ontogenetic samples of extant gorillas.

   A total of 281 wild‐collected individuals were included in the study, divided into four groups that vary taxonomically and ecologically: western lowland gorillas (G. g. gorilla), lowland and highland grauer gorillas(G. b. graueri), and Virunga mountain gorillas (G. b. beringei). Lengths and articular breadths of the major long bones (except the fibula) were measured, and diaphyseal cross‐sectional geometric properties determined using computed tomography. Ages of immature specimens (n = 145) were known or estimated from dental development. Differences between groups in hind limb to forelimb proportions were assessed in both adults and during development.

   Diaphyseal strength proportions among adults vary in parallel with behavioral/ecological differences, and not phylogeny. The more arboreal western lowland and lowland grauer gorillas have relatively stronger forelimbs than the more terrestrial Virunga mountain gorillas, while the behaviorally intermediate highland grauer gorillas have intermediate proportions. Diaphyseal strength proportions are similar in young infants but diverge after 2 years of age in western lowland and mountain gorillas, at the same time that changes in locomotor behavior occur. There are no differences between groups in length or articular proportions among either adults or immature individuals.

   Long bone diaphyseal strength proportions in gorillas are developmentally plastic, reflecting behavior, while length and articular proportions are much more genetically canalized. These findings have implications for interpreting morphological variation among fossil taxa.

    

   more » « less
2. Testing the Giles hypothesis using geometric morphometrics

   https://doi.org/10.1002/ajpa.24219  

   Simons, Evan A. ( January 2021 , American Journal of Physical Anthropology)

   The Giles hypothesis posits that differences in the cranial morphology ofPan troglodytesandGorilla gorillaare largely the result of allometric scaling. However, previous support for the Giles hypothesis was based on bivariate plots of linear measurements. This investigation uses geometric morphometric methods to retest this hypothesis and its prediction that extending the ontogenetic trajectory of a chimpanzee would produce an adult gorilla‐like cranial morphology.

   Forty‐three 3D cranial landmarks were collected from an ontogenetic series of 76Pan troglodytesand 58Gorilla gorillaspecimens. Ontogenetic trajectories of cranial shape change were computed via multivariate regression of Procrustes aligned coordinates against LnCS (size vector) and molar eruption stage (developmental vector). These two vectors were then used in developmental simulations to extend the ontogenetic trajectories of adult chimpanzees. Allometric trajectories of chimpanzees and gorillas were also directly compared using Procrustes ANOVA.

   PanandGorillasignificantly differ in their allometric trajectories, and none of the Pan developmental simulations resembled actual adult gorillas. Additionally, the more thePandevelopmental vector was extended, the more morphologically distinct the simulations became from actual adult gorillas.

   Taken together, these results do not support the Giles hypothesis that allometric scaling is primarily responsible for observed morphological differences between chimpanzee and gorilla crania. This investigation demonstrates that neither “growing” a chimpanzee to the size of a gorilla, nor extending a chimpanzee's developmental shape trajectory will result in an adult gorilla‐like cranial morphology as they differ in their patterns of allometry.

    

   more » « less
3. Interspecific Variation of Calcaneal Morphology in Gorillas

   Harper, Christine M. ; Ruff, Christopher B. ; Sylvester, Adam D. ( February 2019 , American journal of physical anthropology)

   The foot plays a prominent role in weight-bearing suggesting it may reflect locomotor variation. Despite the immense amount of foot research, the calcaneus has been relatively understudied. Here we analyzed the entire calcaneal shape of Gorilla gorilla gorilla (n=41), Gorilla beringei graueri (n=17) and Gorilla beringei beringei (n=8) to understand how morphology relates to locomotor behavior. Calcanei were surface scanned and external shape analyzed using a three-dimensional geometric morphometric sliding semilandmark analysis. Semilandmarks were slid to minimize the bending energy of the thin plate spline interpolation function relative to the updated Procrustes average. Generalized Procrustes Analysis was used to align landmark configurations and shape variation was summarized using a principal components analysis. Procrustes distances between species were calculated and resampling statistics were run to test for group differences. All subspecies demonstrate statistically different morphologies (p<0.005 for pairwise comparisons). G. b. graueri separates from other subspecies based on posterolateral morphology, with G. b. graueri demonstrating an elongated peroneal trochlea, and thus more bone superiorly than G. g. gorilla. Compared to G. b. beringei, G. b. graueri has less bone inferiorly near the tuberosity. Cuboid and posterior talar facet shapes correlate with arboreality. G. b. beringei (most terrestrial) has a flatter cuboid facet and a more transversely oriented/relatively smaller posterior talar facet than G. g. gorilla (most arboreal) and G. b. graueri represents an intermediate morphology. These differences demonstrate a relationship between calcaneal shape and locomotor behavior and suggest that G. b. graueri may load its foot differently from the other subspecies. This project was supported by NSF grant # BCS - 1824630. 

   more » « less
4. Discovery of a bone‐like blood particle in the peripheral circulation of humans and rodents

   https://doi.org/10.1111/micc.12579  

   Prisby, Rhonda ; Ross, Jean ; Opdenaker, Lynn ; McLane, Mary Ann ; Lee, Seungyong ; Sun, Xiangle ; Guderian, Sophie ( July 2019 , Microcirculation)

   To characterize ossified bone marrow blood vessels and confirm the presence of ossified particles (OSP) in humans and rodents.

   Human bone marrow blood vessels were processed for scanning and transmission electron microscopy. Whole blood samples were collected from younger (26‐39 years; n = 6) and older (55‐63 years; n = 6) volunteers and male Fischer‐344 rats (1 month, n = 7; 6 months, n = 7; 12 months, n = 7; 18‐months, n = 6; 24 months, n = 8).OSPin the whole blood samples were sorted and imaged with microscopy to determine diameter, circularity, and solidity. Additionally, the chemical composition ofOSPwas determined via elemental analysis.

   SEMrevealed two types of ossified bone marrow blood vessels: that is, “transitioning” and “ossified.”OSPwere adhered to the surface of transitioning vessels and theoretically gain access to and circulate within the blood. The majority ofOSPwere ≤15 μm in diameter, but many were of sufficient size to serve as emboli (ie, >15 μm).OSPwere predominately oblong in shape and several had jagged tips and edges.

   We introduce a novel, bone‐like blood particle that may be diagnostic of bone marrow blood vessel ossification. Further,OSPmay associate with several disease states (eg, atherosclerosis).

    

   more » « less
5. Gut microbiome composition of wild western lowland gorillas is associated with individual age and sex factors

   https://doi.org/10.1002/ajpa.23842  

   Pafčo, Barbora ; Sharma, Ashok_K ; Petrželková, Klára_J ; Vlčková, Klára ; Todd, Angelique ; Yeoman, Carl_J ; Wilson, Brenda_A ; Stumpf, Rebecca ; White, Bryan_A ; Nelson, Karen_E ; et al ( April 2019 , American Journal of Physical Anthropology)

   Environmental and ecological factors, such as geographic range, anthropogenic pressure, group identity, and feeding behavior are known to influence the gastrointestinal microbiomes of great apes. However, the influence of individual host traits such as age and sex, given specific dietary and social constraints, has been less studied. The objective of this investigation was to determine the associations between an individual's age and sex on the diversity and composition of the gut microbiome in wild western lowland gorillas.

   Publicly available 16S rRNA data generated from fecal samples of different groups ofGorilla gorillagorillain the Central African Republic were downloaded and bioinformatically processed. The groups analyzed included habituated, partially habituated and unhabituated gorillas, sampled during low fruit (dry,n = 28) and high fruit (wet,n = 82) seasons. Microbial community analyses (alpha and beta diversity and analyses of discriminant taxa), in tandem with network‐wide approaches, were used to (a) mine for specific age and sex based differences in gut bacterial community composition and to (b) asses for gut community modularity and bacterial taxa with potential functional roles, in the context of seasonal food variation, and social group affiliation.

   Both age and sex significantly influenced gut microbiome diversity and composition in wild western lowland gorillas. However, the largest differences were observed between infants and adults in habituated groups and between adults and immature gorillas within all groups, and across dry and wet seasons. Specifically, although adults always showed greater bacterial richness than infants and immature gorillas, network‐wide analyses showed higher microbial community complexity and modularity in the infant gorilla gut. Sex‐based microbiome differences were not evident among adults, being only detected among immature gorillas.

   The results presented point to a dynamic gut microbiome inGorillaspp., associated with ontogeny and individual development. Of note, the gut microbiomes of breastfeeding infants seemed to reflect early exposure to complex, herbaceous vegetation. Whether increased compositional complexity of the infant gorilla gut microbiome is an adaptive response to an energy‐limited diet and an underdeveloped gut needs to be further tested. Overall, age and sex based gut microbiome differences, as shown here, maybe mainly attributed to access to specific feeding sources, and social interactions between individuals within groups.

    

   more » « less