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Geometric morphometrics of hominoid thoraces and its bearing for reconstructing the ribcage of H. naledi

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Abstract

H. naledi shows a mosaic morphological pattern with several derived (Homo-like) features of the skull, hands and feet, and primitive (australopith- like) features in the ribcage, shoulder, and pelvis. This pattern reflects a morphology that might be expected of a hominin at the evolutionary transition between Australopithecus and Homo. Two thoracic vertebrae from levels 10 and 11 and the proximal aspect of an 11th rib were found in near anatomical connection in the Dinaledi Chamber of Rising Star cave, therefore likely belonging to the same individual. In this study we explore this association and report our ongoing work towards a quantitative 3D reconstruction of the H. naledi thorax. We measured 512 3D-(semi)landmarks on human and other hominoid ribcages (hylobatids, Pongo, Gorilla, Pan; N=33) for geometric morphometric analyses. Covariation between the 11th rib and remaining thorax shape was analyzed by partial least squares analysis (PLS) and overall thorax variation by principal components analysis (PCA). PCA results show wide ranges of complex thoracic variation. Gorilla and Pan are characterized by highly constricted upper thoraces when compared to their wide lower ribcages. Pongo and hylobatids have less narrow upper but also wide lower thoraces. Those of humans are expanded superiorly, narrow inferiorly, and with declined ribs. PLS analyses suggest that the morphology of the articulated rib-vertebra complex at the 11th level of H. naledi is compatible with a ribcage with declined ribs and inferiorly wider than observed in humans. This corresponds with evidence for laterally flared iliac blades of the H. naledi pelvis.
Conference Program
111
ABSTRACTS
I used a General Linear Model (GLM) to quantify
the relationship between MAP, land cover, and
the average trait values for all species occurring
at each location. Next, I measured astragalus
ecometric traits on 216 fossil astragali from the
Shungura Formation (covering the period 3.4 –
1.9 Ma). I applied the GLM to infer MAP for each
Shungura geological member using the trait aver-
ages for all specimens in each member.
Results on modern data demonstrate that several
astragalus and metatarsal ecometric traits
explain major proportions of variation in MAP and
land cover (R2 > 0.6). In the Shungura Formation,
results are consistent with habitats with MAP
values ranging from ca. 700 mm to nearly 1600
mm. Although challenges remain in directly
comparing the modern and fossil datasets, the
ecometric method offers a promising way to
quantitatively characterize hominin habitats.
Supported by a Wenner-Gren Foundation Dissertation
Research Grant (number 8557) and the the GW
Signature Program.
Water Soluble Nutrient Intake and Leptin
Phenotypes in the Kansas Mennonite
CHRISTOPHER E. BARRETT1, MICHAEL
CRAWFORD2 and M.J. MOSHER3
1Anthropology, University of Kansas, 2Anthropology,
University of Kansas, 3Anthropology, Western
Washington University
Diseases of Western Civilization and metabolic
dysfunctions have spread globally with alarming
speed and prevalence. Causes are a racemic
mix of environmental, biological, nutritional and
behavioral factors which vary between popu-
lations and sex. Nutrients and their cellular
receptors work in concert to modify genetic
activity using nutrigenetic pathways. These
gene-nutrient interactions are known to amelio-
rate certain risk factors including aberrant levels
of hormones such as leptin. Adipose derived
hormones, or ‘adipokines’, such as leptin regulate
many homeostatic processes with novel utility
in treating chronic and metabolic conditions.
Research in human and non-human models
suggests possible connections between select
lipid or water soluble micronutrients and meta-
bolic biomarkers. However, these reports are
too often exclusively reductionist, use obsolete
methodologies or hyper focus on a single nutrient
explanations.
We test the relationships between micronu-
trient intake and variation in leptin phenotypes
using sex-specic and multi-nutrient models,
examining the associations with measures of
disease risk including adiposity, blood lipids
and adipokine concentrations in a population
of Kansas Mennonite (N=160) with histories of
ssion and fusion. Multivariate regressions were
run sex-specically (females=84; males=76)
and were controlled for adipose tissue. Intake
of water soluble vitamin B6 was signicant for
leptin phenotypes in women (β=0.324, p=0.043).
Vitamin B6 is needed for neurotransmitter
synthesis and regulating the bodily clock and
epigenetic methylation. Results suggest associ-
ations between nutritional intake and metabolic
biomarkers may be nutrient and sex-specic.
Stable Isotope Evidence for Salmon
Consumption in the Prehistoric
Sacramento Valley of California
ERIC J. BARTELINK1, JAMES NELSON2, DENISE
FURLONG3, STEFANIE KLINE4, JULIA PRINCE-
BUITENHUYS5, AMY MACKINNON6 and FRANK
BAYHAM1
1Department of Anthropology, California State
University, Chico, 2Cultural Resources Division, Pacic
Gas & Electric, 3Archaeology Division, Furlong &
Associates, 4Cultural Rescue Initiative, Smithsonian,
5Department of Anthropology, Notre Dame,
6Archaeology Division, Parsons Brinckerhoff
Evidence for the prehistoric consumption of
salmon in the Sacramento Valley is based
primarily upon the ethnographic record and
ethnohistoric accounts. These lines of evidence,
in conjunction with the known seasonal spawning
runs of salmon documented during the historic
period, suggest that salmon were a highly valued
food resource throughout the Sacramento River
watershed. However, zooarchaeological studies
have found that salmon bones comprise a rela-
tively small portion of sh bone assemblages in
the southern Sacramento Valley region. To esti-
mate the dietary importance of salmon along the
northern and southern ends of the Sacramento
Valley, stable carbon and nitrogen isotopes of
bone collagen are examined from human burials
from six late Holocene (4500–200 B.P.) central
and northern California sites.
Individuals from the southern Sacramento Valley
show low δ13C and δ15N values, regardless of
time period, and very little dietary variation. These
values are most consistent with a dietary focus
on freshwater sh with small contributions from
salmon. However, individuals from the northern
Sacramento Valley show notably high δ13C and
δ15N values, clearly indicating a larger contribu-
tion of salmon to the diet. Together, these data
indicate strong evidence for salmon consump-
tion in the northern Sacramento Valley, but not
in the southern Sacramento Valley. These data
corroborate patterns observed in late Holocene
zooarchaeological assemblages, but contra-
dict ethnographic and ethnohistoric accounts
regarding the importance of salmon in the
southern Sacramento Valley.
Funding was provided by the Wenner-Gren Foundation
(Grant No. 7163) and National Science Foundation
(Grant No. 0424292).
Guided by voices: using social media to
target small ape surveys in Peninsular
Malaysia
THAD Q. BARTLETT1, SUSAN LAPPAN2 and NADINE
RUPPERT3
1Anthropology, The University of Texas at San
Antonio, 2Anthropology, Appalachian State University,
3School of Biological Sciences, Universiti Sains
Malaysia
Citizen science communicated by social media
has the potential to play an important role in
primate conservation and assessment, particu-
larly for populations that have not been surveyed
recently. In preparation for a survey of small apes
(Hylobatidae) in the Malay Peninsula we reviewed
common social media outlets (e.g., YouTube,
SoundCloud, and hosted blogs) for recent records
of three hylobatid species (Hylobates lar, H. agilis,
and Symphalangus syndactylus) throughout
the peninsula. We deemed a record reliable if it
included a date of observation, location informa-
tion, and an audio recording, photograph, or video.
Using these online records, we identied 23 sites
outside of protected state and national parks with
recent records indicating the presence of small
apes. A preliminary ground survey during August
2016 conrmed the presence of the species indi-
cated at 3 of these sites—Bukit Fraser (H. lar and
S. syndactylus), Bukit Larut (H. agilis), and Genting
Highlands (S. syndactylus). Hylobatids were not
observed at two other sites (Cameron Highlands
and Bukit Tinggi) where records indicated their
presence as recently at 2010. We relied on audi-
tory methods to document the occurrence of
small apes, so it is possible that animals were
present but not detected, since hylobatids do not
call every day. Nonetheless, these results suggest
that social media records of primates may help
to identify sites and habitats under high threat or
where extinction has occurred very recently. One
issue that must be resolved is how to aggregate
social media records without providing detailed
information to potential poachers.
Funding provided by The University of Texas at San
Antonio.
Geometric morphometrics of hominoid
thoraces and its bearing for reconstructing
the ribcage of H. naledi
MARKUS BASTIR1,2, DANIEL GARCÍA-MARTÍNEZ1,2,
SCOTT A. WILLIAMS2,3,4, MARC R. MEYER5, SHAHED
NALLA2,6, PETER SCHMID2,7, ALON BARASH8,
MOTOHARU OISHI9, NAOMICHI OGIHARA10,
STEVEN E. CHURCHILL11,2, JOHN HAWKS12,2 and
LEE R. BERGER2
1Department of Paleobiology, Museo Nacional de
Ciencias Naturales CSIC, 2Evolutionary Studies
Institute and Centre for Excellence in PalaeoSciences,
University of the Witwatersrand, 3Center for the Study
of Human Origins, Department of Anthropology,
New York University, 4New York Consortium
in Evolutionary Primatology, 5Department of
Anthropology, Chaffey College, 6Department
86th Annual Meeting of the American Association of Physical Anthropologists
112
ABSTRACTS
of Human Anatomy and Physiology, Faculty of
Health Sciences, University of Johannesburg,
7Anthropological Institute and Museum, University
of Zurich, 8Faculty of Medicine Galilee, Bar Ilan
University, 9Laboratory of Anatomy 1, School of
Veterinary Medicine, Azabu University, 10Department
of Mechanical Engineering, Faculty of Science
and Technology, Keio University, 11Department
of Evolutionary Anthropology, Duke University,
12Department of Anthropology, University of
Wisconsin-Madison
H. naledi shows a mosaic morphological pattern
with several derived (Homo-like) features of the
skull, hands and feet, and primitive (australo-
pith-like) features in the ribcage, shoulder, and
pelvis. This pattern reects a morphology that
might be expected of a hominin at the evolu-
tionary transition between Australopithecus and
Homo. Two thoracic vertebrae from levels 10
and 11 and the proximal aspect of an 11th rib
were found in near anatomical connection in
the Dinaledi Chamber of Rising Star cave, there-
fore likely belonging to the same individual.
In this study we explore this association and
report our ongoing work towards a quantitative
3D reconstruction of the H. naledi thorax. We
measured 512 3D-(semi)landmarks on human
and other hominoid ribcages (hylobatids, Pongo,
Gorilla, Pan; N=33) for geometric morphometric
analyses. Covariation between the 11th rib and
remaining thorax shape was analyzed by partial
least squares analysis (PLS) and overall thorax
variation by principal components analysis
(PCA). PCA results show wide ranges of complex
thoracic variation. Gorilla and Pan are character-
ized by highly constricted upper thoraces when
compared to their wide lower ribcages. Pongo and
hylobatids have less narrow upper but also wide
lower thoraces. Those of humans are expanded
superiorly, narrow inferiorly, and with declined
ribs. PLS analyses suggest that the morphology
of the articulated rib-vertebra complex at the 11th
level of H. naledi is compatible with a ribcage with
declined ribs and inferiorly wider than observed
in humans. This corresponds with evidence for
laterally ared iliac blades of the H. naledi pelvis.
Funding: CGl2012-37279, CGL2015-63648-P (MINECO,
Spain), The Leakey Foundation
Isotopic analysis of pre-Columbian Groups
from the Brazilian coast
MURILO Q. R. BASTOS1, ANDREA LESSA1, ROBERTO
V. SANTOS2 and CLAUDIA RODRIGUES-CARVALHO1
1Anthropology, Museu Nacional, Universidade Federal
do Rio de Janeiro, 2Geosciences, Universidade de
Brasília
Carbon, nitrogen and strontium isotope analysis
have been carried out on skeletal remains exca-
vated from shellmounds and other pre-Columbian
sites found in the South and Southeastern coast
of Brazil in order to revise old models and propose
new hypothesis of these groups’ diet, residen-
tial mobility and some other aspects of their
lives. Bone, dentin and enamel preparation were
performed considering diagenetic, breastfeeding
period and isobaric interferences.
In the case of Praia da Tapera and Forte Marechal
Luz, coastal sites from Santa Catarina state that
presented ceramics associated with inland
groups, the isotopic analysis done on dental
enamel and dentin pointed out that all individuals
had a strong relation with the coast since their
childhood, weakening the model that these sites
were occupied by individuals from the plateau.
The wider strontium variation found in women
also suggests coastal migration and could be
related to post-marital practices.
While archaeological and isotopic analysis
indicate that shellmound builders groups had
in general marine food as the most impor-
tant protein source, individuals analyzed from
the Zé Espinho Shellmound, in Rio de Janeiro,
presented a very diversied diet, deconstructing
the perspective that these groups had an homog-
enous nutrition.
New isotopic studies related to pre-Columbian
costal Brazilian populations are underway in
order to enhance our comprehension about their
economy, life style and trade between these
groups. However, due to the economic crisis
Brazil is facing for the past few years, the budget
for archaeological studies is being reduced,
compromising the progress of our research.
Scholarship funded by Conselho Nacional de
Desenvolvimento Cientíco e Tecnológico (CNPq), Pós
Doutorado Júnior Project number: 151004/2014-5.
Agent-Based Modeling of Geographic
Barriers and Gene Flow in
Fuego-Patagonia
VINCENT M. BATTISTA
Anthropology, University of Michigan
The rst people to set foot in Southern Patagonia
(Chile and Argentina) navigated mountainous
terrain dominated by ice elds and glaciers.
The distribution of rare mtDNA haplogroups
and distinct craniometric traits found in Fuego-
Patagonia are possibly the result of this complex
topography and isolation by distance. Presented
is an agent-based model that investigates
the hypothesis that geographic barriers led to
marked genetic drift and a strong founder effect
in southernmost Patagonia.
This model generates a population of agents
randomly distributed atop an interactive map of
Late Pleistocene Patagonia; these “hunters” can
disperse in random headings and can oppor-
tunistically admix with any other agents they
encounter. Preliminary results suggest that
barriers such as the Andes, glacial elds, and
the Straits of Magellan alone could not prevent
large amounts of geneow from either entering
or leaving Fuego-Patagonia. However, recursive
catastrophic events (e.g., volcanic eruptions,
marine incursions) on small, structured groups
minimized gene ow between mainland and
island populations. Given that this model does
not control for variation in climate, it is possible
that environmental factors or merely a lack of
adaptive mechanisms (e.g., to cold climate) also
played a role in preventing population expansions
into or away from Fuego-Patagonia. Overall, this
exploratory and simplistic model suggests that
static geographic barriers alone cannot account
for genetic isolation in this topographically
complex region.
Dental developmental patterns and tooth
internal structure in European Upper
Paleolithic humans
PRISCILLA BAYLE1 and MONA LE LUYER1,2
1UMR5199 PACEA, University of Bordeaux, 2School of
Anthropology and Conservation, University of Kent
While differences have been reported between
Neandertals and extant humans in their patterns
of dental development and internal tooth
structure, few studies have focused on the eval-
uation of these parameters in Upper Paleolithic
humans. Above all, dental maturational patterns
and metameric variation in tissue proportions
along the arcade, and how these processes
are linked together, have not been quantied
through the Upper Paleolithic. Here we used
microCT-based data, as well as radiographic and
CT records, to nely quantify these variables in
the deciduous and permanent dentitions of the
Gravettian child from Lagar Velho, in Portugal,
the Middle Magdalenian individual Lafaye 25
from Bruniquel, and the Epipaleolithic child from
La Madeleine, both in France, and compare
the measures between themselves and to the
Neandertals, historical and extant humans of
worldwide origins. While the Gravettian child
shows a discrepancy in its incisor relative to
molar development compared to extant children,
the Magdalenian and Epipaleolithic individuals
t this comparative sample and differ from the
Neandertal pattern. This is complemented by
differences in tissue proportions between Lagar
Velho and the two more recent individuals, the
rst having particularly large incisor dentine
volumes and high metameric variation. Although
future investigations are needed to unlock the
genetically- and/or functionally-related factors
sustaining these observations, our results
suggest that the dental developmental and struc-
tural variation, still far from being documented,
may bring signicant contribution to the recent
reappraisal of the human paleobiological and
phylogenetic history throughout the European
Upper Paleolithic.
... East African hominins such as A. afarensis were more fully engaged terrestrial bipeds ( Kramer and Eck, 2000;Latimer and Lovejoy, 1989;Lovejoy, 2005;Lovejoy, 2007;MacLatchy, 1996;Pontzer, 2017;Ward, 2002) compared with South African hominins signaling a more significant arboreal behavioral component, such as A. sediba and H. naledi ( Bastir et al., 2017;Churchill et al., 2013;Frater, Haeusler, & Schmid, 2014;Kivell et al., 2015;Kivell, Kibii, Churchill, Schmid, & Berger, 2011;Rein, Harrison, Carlson, & Harvati, 2017;Schmid et al., 2013;Williams et al., 2017). Because our hominin sample is small our results must be interpreted with caution, but the data here support our first hypothesis that with the advent of full time terrestrial orthogrady, hominins will exhibit reduced uncinate process depth. ...
Article
Objectives: Uncinate processes are protuberances on the cranial surface of subaxial cervical vertebrae that assist in stabilizing and guiding spinal motion. Shallow uncinate processes reduce cervical stability but confer an increased range of motion in clinical studies. Here we assess uncinate processes among extant primates and model cervical kinematics in early fossil hominins. Materials and Methods: We compare six fossil hominin vertebrae with 48 Homo sapiens and 99 nonhuman primates across 20 genera. We quantify uncinate morphology via geometric morphometric methods to understand how uncinate process shape relates to allometry, taxonomy, and mode of locomotion. Results: Across primates, allometry explains roughly 50% of shape variation, as small, narrow vertebrae feature the relatively tallest, most pronounced uncinate processes, whereas larger, wider vertebrae typically feature reduced uncinates. Taxonomy only weakly explains the residual variation , however, the association between Uncinate Shape and mode of locomotion is robust, as bipeds and suspensory primates occupy opposite extremes of the morphological continuum and are distinguished from arboreal generalists. Like humans, Australopithecus afarensis and Homo erectus exhibit shallow uncinate processes, whereas A. sediba resembles more arboreal taxa, but not fully suspensory primates. Discussion: Suspensory primates exhibit the most pronounced uncinates, likely to maintain visual field stabilization. East African hominins exhibit reduced uncinate processes compared with African apes and A. sediba, likely signaling different degrees of neck motility and modes of locomotion. Although soft tissues constrain neck flexibility beyond limits suggested by osteology alone, this study may assist in modeling cervical kinematics and positional behaviors in extinct taxa.
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