Presented in the session “Global Leadership in Dental Anthropological Research: A symposium in honor of G. Richard Scott." The Arizona State University Dental Anthropology System (ASUDAS) or Turner-Scott System revolutionized the use of dental morphology for reconstructing evolutionary processes in past populations. By providing globally-recognized data collection standards, the system has elevated the status of dental morphology to an indispensable line of evidence in biodistance research. The efficacy of morphological data rests upon foundational assumptions about underlying tooth crown biology; namely, that the traits are highly heritable and minimally sexually dimorphic. Scott and colleagues have also outlined best practices for the application of dental morphology to biodistance studies, most aimed at curtailing genetic redundancy in multivariate datasets (see Turner et al., 1991). Quantitative genetic approaches have the potential to validate these assumptions. Here, we present the first robust estimates of heritability and genetic correlation for ASUDAS crown characters. Data were collected from a casted sample of South Carolina Gullah individuals (N=469) and analyzed using maximum likelihood variance components analysis. While several postcanine traits yielded heritability estimates of 0.0, mean estimates across statistically significant models were moderate to high (anterior=0.34; postcanine=0.75). Results of covariate screening support the long-held assumption that ASUDAS traits are sexually monomorphic, with the exception of canine marginal/cingular ridge characters and certain molar accessory cusps. Additionally, patterns of heritability and genetic correlation groundtruth most prescribed biodistance practices: dichotomizing trait expression, collapsing bi-antimeric datasets, and prioritizing traits scored on key (sensu Scott et al., 2018) teeth. Notwithstanding, our results suggest that certain assumptions require reconsideration and underscore the importance of continued validation work in additional populations.

A specific allotrope of titanium dioxide (anatase) was synthesized with a highly anisotropic morphology ({001}-anatase) dominated by the {001} facet (81%). its surface chemistry after dehydroxylation was studied by 1H NMR and FT-IR. Influence of surface fluorides on surface chemistry was also studied by 1H NMR, FT-IR and DFT. Full attribution of the IR and NMR spectra of anatase with dominant {001} facets could be provided based on experimental data and further confirmed by DFT. Our results showed that chemisorbed H2O are still present on anatase after dehydroxylation at 350°C, and that the type of surface hydroxyls present on the {001} facet is dependent on the presence of fluorides. They also provided general insight on the nature of surface species on both fluorinated and fluorine-free anatase. The use of vanadium oxychloride (VOCl3) allowed determining the accessibility of the various OH groups spectroscopically observed. A platinum complex, (CH3)2Pt(COD), is then grafted via surface organometallic chemistry (SOMC) on morphology-controlled Anatase TiO2 to generate single, isolated Pt atoms on TiO2 nano-platelets. The resulting material is characterized by FT-IR, High resolution scanning transmission electron microscopy (HRSTEM), NMR, and XAS, and then used to perform photocatalytic water splitting. The photocatalyst with SOMC-grafted Pt shows superior performance in photocatalytic hydrogen evolution and strongly suppresses backwards reaction of H2 and O2 forming H2O under dark conditions, compared to photocatalyst prepared by standard wet impregnation at the same Pt loading. However, single Pt atoms on this surface also rapidly coalesce into nanoparticles under photocatalytic conditions. It was also found that adsorbtion of carbon monoxide gas at room temperature also triggers the aggregation of Pt single atoms into nanoparticles. A detailed mechanism is investigated for the mobility of Pt in the formation of its carbonyls using density functional theory (DFT) calculations.

Kenaf fiber is increasingly getting the attention of the industries due to its excellent mechanical properties, feasibility, growth rate, and ease of cultivation. On the other hand, cellulose nanofibril is one of the important building blocks of all the bast fibers which significantly contributes to their mechanical properties. However, most of the studies in the literature have estimated the value of axial elastic modulus for fiber-bundles which has some unavoidable issues resulting in incorrect modulus. Moreover, the transverse elastic modulus is another important parameter that also needs to be studied. Hence, to compensate for the gap in the literature, a single unit of both kenaf microfiber and cellulose nanofibril have been subjected to nanomechanical characterization to analyze their surface morphology and determine their elastic modulus in the axial and transverse direction. The experiments also pave to a protocol to characterize micro and nanofibrils nanomechanically and determine their elastic moduli.

The neotropical genus Exostema comprises 25 species of trees and shrubs, ranging in distribution from Bolivia to Mexico and throughout the West Indies, with most species endemic to the Greater Antilles. Infrageneric relationships and species-level patterns of evolution were investigated in phylogenetic analyses using morphological, molecular, and combined data sets. All data sets resolved three main species groups which correspond to the three sections recognized by McDOWELL (1996). However, the analyses of ITS sequence data placed the two South American species basal to the three main clades. Otherwise, the morphological and molecular data are highly compatible, and produce a more robust yet consistent phylogeny in the combined data analysis. Morphological evolution in Exostema involves many specializations for xeric habitats, reflecting repeated ecological shifts from moist forest to exposed, seasonally dry environments during the diversification of the genus. Both moth and bee pollination syndromes are found in Exostema, and shifts in pollination ecology appear pivotal to the differentiation of the three sections. Biogeographically, Exostema likely originated in South America and migrated via Central America to the Greater Antilles, where the morphological diversification and speciation are most extensive.

Quercus praedelavayi Xing Y.W. et Zhou Z.K. sp. nov. is reported from the upper Miocene of the Xianfeng flora in central Yunnan, southwestern China. The fossil species is identified based on the detailed leaf morphological and cuticular examinations. The primary venation is pinnate and the major secondary venation is craspedodromous with regular spacing. Stomata are anomocytic and occur on abaxial epidermis. Trichome bases are unicellular and multicellular. The new fossil species shows the closest affinity with Quercus delavayi, an extant species distributing in southwestern China. The responses of the functional leaf traits to the climate change were studied by comparing the leaf characters of fossil species and its nearest living relative. The stomatal density of Q. praedelavayi is higher than Q. delavayi, which suggests a lower palaeoatmospheric CO2 concentration during the late Miocene. The trichome base density of Q. praedelavayi is higher than the extant Q. delavayi. Considering the palaeoclimatic reconstruction of Xianfeng flora, it rejected the hypothesis that increase in trichome density is an adaptation to the drier environment.

Quercus praedelavayi Xing Y.W. et Zhou Z.K. sp. nov. is reported from the upper Miocene of the Xianfeng flora in central Yunnan, southwestern China. The fossil species is identified based on the detailed leaf morphological and cuticular examinations. The primary venation is pinnate and the major secondary venation is craspedodromous with regular spacing. Stomata are anomocytic and occur on abaxial epidermis. Trichome bases are unicellular and multicellular. The new fossil species shows the closest affinity with Quercus delavayi, an extant species distributing in southwestern China. The responses of the functional leaf traits to the climate change were studied by comparing the leaf characters of fossil species and its nearest living relative. The stomatal density of Q. praedelavayi is higher than Q. delavayi, which suggests a lower palaeoatmospheric CO2 concentration during the late Miocene. The trichome base density of Q. praedelavayi is higher than the extant Q. delavayi. Considering the palaeoclimatic reconstruction of Xianfeng flora, it rejected the hypothesis that increase in trichome density is an adaptation to the drier environment.

Here we present the most detailed morphological study of the auditory region of a tremarctinae bear, Arctotherium tarijense Ameghino. In addition, we provide new anatomical information of the Tremarctinae inner ear, such as coplanarity and deviation from orthogonality of the semicircular canals, as an approach to infer the head movements which encountered the extinct forms in locomotion. Based on morphological comparisons, A. tarijense exhibits the following particular features: the cavum tympani presents the highest relative volume compared with other ursids; the processus paraoccipitalis has a foramen that is absent in other tremarctines; there is only one (ventral) recess in the anterior region of the cavum tympani; and the recessus epytimpanicus is the smallest for all ursids studied. In relation to the inner ear, A. tarijense shows the lowest values of orthogonality deviation and highest scores of locomotor agility. Based on this, is possible to make a preliminary proposal that this species had a relative high vestibular sensibility and therefore a better ability to explore different kind of habitats. However, this hypothesis might be contrasted among bears taking into account the orientation of each semicircular canal in a phylogenetic framework.

The extinct taxon Dasypus bellus has long been considered identical to the extant Dasypus novemcinctus osteologically when disregarding allometric differences. In this study, we undertake a preliminary investigation into this extinct taxon and an extant relative D. novemcinctus, by comparing the calcanea of these two dasypodids. Clear osteological differences are observed including a mediolaterally-reduced facet region, an anteriorly-shortened calcaneal head, a reduced peroneal process, and a curved and dorsoventrally-shortened calcaneal foot in D. bellus. Such characters are not allometric and likely correlate to distinct behavioral differences. Specifically, we suggest that D. novemcinctus maintains a more fossorial lifestyle, while the larger D. bellus was likely more terrestrial, with potentially little digging behavior. Such lifestyle differences could not only explain the osteological differences present, but also why fossils of D. bellus have been recovered farther north than the present range of D. novemcinctus. Fossils of Dasypus may need to be re-evaluated to determine how these two taxa relate temporally and geographically, which may have further implications regarding some past interpretations and provide new details on the behavior and potential relationships between these (and other) xenarthrans.

Pocket gophers (family Geomyidae) are the dominant burrowing rodents in North America today. Their fossil record is also incredibly rich; in particular, entoptychine gophers, a diverse extinct subfamily of the Geomyidae, are known from countless teeth and jaws from Oligocene and Miocene-aged deposits of the western United States and Mexico. Their postcranial remains, however, are much rarer and little studied. Yet, they offer the opportunity to investigate the locomotion of fossil gophers, shed light on the evolution of fossoriality, and enable ecomorphological comparisons with contemporaneous rodents. We present herein a quantitative study of the cranial and postcranial remains of eight different species of entoptychine gophers as well as many contemporary rodent species. We find a range of burrowing capabilities within Entoptychinae, including semifossorial scratch-digging animals and fossorial taxa with cranial adaptations to burrowing. Our results suggest the repeated evolution of chisel-tooth digging across genera. Comparisons between entoptychine gophers and contemporaneous rodent taxa show little ecomorphological overlap and suggest that the succession of burrowing rodent taxa on the landscape may have had more to do with habitat partitioning than competition.

Objectives: This article presents estimates of narrow-sense heritability and bivariate genetic correlation for a series of morphological crown variants of the anterior dentition. These results provide insight into the value of dental phenotypes as evolutionary proxies, as well as the development of tooth crowns as integrated or modular structures. Materials and Methods: African American dental casts from the Menegaz-Bock collection were scored for a standard set of dental morphological variables using the Arizona State Dental Anthropology System. Estimates of narrow-sense heritability and genetic correlations were generated using SOLAR v. 8.1.1, controlling for the covariates of age, sex, and birth year. Analyses were run using ordinal/continuous scale variables that were then dichotomized at various breakpoints, consistent with standard practices in dental anthropology. Results: Heritability estimates were low to moderate for most traits, and lower in magnitude than those reported for odontometric data from the same study sample. Only winging, canine shoveling, and canine double shoveling returned narrow-sense heritabilities that did not differ significantly from zero. Genetic correlations were high among antimeres and metameres and low for different traits scored on the same tooth crown. These results affirm standard data cleaning practices in dental biodistance. Double shoveling was atypical in returning strong negative correlations with other traits, shoveling in particular. Conclusions: Additive genetic variation contributes to dental morphological variation, although the estimates are uniformly lower than those observed for odontometrics. Patterns of genetic correlation affirm most standard practices in dental biodistance. Patterns of negative pleiotropy involving lingual and labial crown features suggest a genetic architecture and developmental complex that differentially constrain morphological variation of distinct surfaces of the same tooth crown. These patterns warrant greater consideration and cross-population validation.