Damiano Marchi | Università di Pisa (original) (raw)

Papers by Damiano Marchi

American journal of biological anthropology, Nov 16, 2021

ObjectivesLong bone variations during growth are susceptible to the combined action of nutritiona... more ObjectivesLong bone variations during growth are susceptible to the combined action of nutritional, hormonal, and genetic factors that may modulate the mechanical forces acting upon growing individuals as they progressively acquire a mature gait. In this work, we explore diaphyseal length and breadth variations of tibia and fibula during ontogeny (a) to test the presence of changes in relation to early toddling, and (b) to further our understanding of developmental patterns in relation to sex.Materials and MethodsLengths, breadths, and indices were analyzed on right and left leg bones of 68 subadult individuals (Human Identified Skeletal Collection of the University of Bologna, Italy). Analyses included intersex and age classes (1, 0–1 year; 2, 1.1–3 years; 3, 3.1–6 years) comparisons, linear regressions with age and assessment of correlation among tibial and fibular measurements, as well as principal component analysis.ResultsA significant difference emerged among age class 1 and the others. Age class 1 and 3 differ between them, while age class 2 overlaps with the others. No sex dimorphism was detected. All measurements were strongly correlated with age. Tibial and fibular measurements correlated with each other.ConclusionsOur results relate the progressive emergence of toddling attempts in growing individuals at the end of the first year of age. No significant sex differences were found, suggesting that tibial and fibula growth might diverge between sexes in later childhood. We provide quantitative data regarding tibial and fibular linear growth and its timing in a modern documented osteological sample from Italy.

The 85th Annual Meeting of the American Association of Physical Anthropologists, Atlanta, GA, 2016

Rising Star Cave is located in the Cradle of Humankind World Heritage site near Krugersdorp in So... more Rising Star Cave is located in the Cradle of Humankind World Heritage site near Krugersdorp in South Africa. In November 2013 and March 2014 more than 1500 hominin fossil elements attributed to a new species, Homo naledi, were recovered and catalogued representing at least a dozen individuals. Only 20 out of 206 bones in the human body are not in the collection as currently represented from the excavation. The thigh and leg of H. naledi, which are represented by 121 femoral, patellar, tibial, and fibular elements, are marked by a mosaic of primitive, derived, and unique traits that are functionally indicative of a bipedal hominin capable of long distance walking and, possibly, running. Traits shared with australopiths include a long, tall, and anteverted femoral neck, a mediolaterally compressed tibia, and a relatively circular fibular neck. Derived traits shared with Homo include a well-marked linea aspera, anteroposteriorly thick patellae, relatively long tibiae, and gracile fibulae with laterally oriented lateral malleoli. Unique features include the presence of two pillars on the superior aspect of the femoral neck and a strong distal insertion of the pes anserinus on the tibia. The mosaic morphology of the H. naledi thigh and leg appears most consistent with a species intermediate between Australopithecus spp. and H. erectus and, accordingly, may offer insight into the nature of the Australopithecus-Homo morphological transition. These fossils also expand the morphological diversity of the Homo lower limb, perhaps indicative of locomotor diversity in our genus.

Journal of Anatomy, Jun 25, 2022

American journal of biological anthropology, Jan 19, 2023

Journal of Morphology, Jun 20, 2016

Palaeopropithecids, or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;... more Palaeopropithecids, or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;sloth lemurs,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; are a diverse clade of large-bodied Malagasy subfossil primates characterized by their inferred suspensory positional behavior. The most recently discovered genus of the palaeopropithecids is Babakotia, and it has been described as more arboreal than Mesopropithecus, but less than Palaeopropithecus. In this article, the within-bone and between-bones articular and cross-sectional diaphyseal proportions of the humerus and femur of Babakotia were compared to extant lemurs, Mesopropithecus and Palaeopropithecus in order to further understand its arboreal adaptations. Additionally, a sample of apes and sloths (Choloepus and Bradypus) are included as functional outgroups composed of suspensory adapted primates and non-primates. Results show that Babakotia and Mesopropithecus both have high humeral/femoral shaft strength proportions, similar to extant great apes and sloths and indicative of forelimb suspensory behavior, with Babakotia more extreme in this regard. All three subfossil taxa have relatively large femoral heads, also associated with suspension in modern taxa. However, Babakotia and Mesopropithecus (but not Palaeopropithecus) have relatively small femoral head surface area to shaft strength proportions suggesting that hind-limb positioning in these taxa during climbing and other behaviors was different than in extant great apes, involving less mobility. Knee and humeral articular dimensions relative to shaft strengths are small in Babakotia and Mesopropithecus, similar to those found in modern sloths and divergent from those in extant great apes and lemurs, suggesting more sloth-like use of these joints during locomotion. Mesopropithecus and Babakotia are more similar to Choloepus in humerofemoral head and length proportions while Palaeopropithecus is more similar to Bradypus. These results provide further evidence of the suspensory adaptations of Babakotia and further highlight similarities to both extant suspensory primates and non-primate slow arboreal climbers and hangers. J. Morphol., 2016. © 2016 Wiley Periodicals, Inc.

Journal of Human Evolution, Aug 1, 2015

Journal of Human Evolution, Dec 1, 2020

International Journal of Osteoarchaeology, Sep 1, 1999

Journal of Human Evolution, Dec 1, 2005

Homo-journal of Comparative Human Biology, 2002

Journal of Human Evolution, Jul 1, 2019

ABSTRACT In questo studio, le caratteristiche strutturali dell’arto superiore (omero) e di quello... more ABSTRACT In questo studio, le caratteristiche strutturali dell’arto superiore (omero) e di quello inferiore (femore e tibia) sono state analizzate per ricostruire le strategie di sussitenza delle popolazione neolitiche liguri. Il metodo d’indagine utilizzato consiste nello studio della geometria delle sezione a metá diafisi dell’osso. I risultati riguardanti l’omero evidenziano un alto livello di robustezza suggerendo un uso frequente dell’arto superiore nelle attività di sussistenza. Lo studio della lateralizzazione mostra per gli uomini un’elevata lateralizzazione, associabile a frequenti attivitá unimanuali, mentre per le donne la lateralizzazione è molto bassa e associabile ad un frequente uso di macine a due mani per la macinatura dei cereali. I neolitici liguri non mostrano la riduzione nella robustezza dell’arto inferiore che è caratteristica del campione tardo neolitico di confronto, e risultano più simili, sia nei livelli di robustezza che negli indici di forma diafisaria, alle popolazioni di confronto altamente mobili del Paleolitico Superiore Recente. Inoltre, gli uomini neolitici liguri risultano molto più robusti delle donne suggerendo una marcata differenziazione dei ruoli tra i sessi. I risultati dell’analisi dell’analisi biomeccanica dell’arto inferiore suggeriscono che i neolitici liguri fossero una popolazione molto mobile su un territorio accidentato e forniscono supporto all’ipotesi basata su evidenze archeologiche che queste popolazioni conducessero attività di sussistenza prevalentemente pastorali.

American Journal of Physical Anthropology, Jun 22, 2019

American Journal of Physical Anthropology, 2011

ABSTRACT Although previous studies of the long bones of Homo floresiensis revealed that this spec... more ABSTRACT Although previous studies of the long bones of Homo floresiensis revealed that this species retained primitive characteristics of body shape and interlimb proportions, the H. floresiensis fibula remains an unexamined part of the equation. The leg of modern humans reflects our status as habitual bipeds and is signaled by a gracile fibula relative to a more robust, weight-bearing tibia. This study investigated whether LB1, the type specimen of H. floresiensis, possesses a robust fibula or displays the gracile fibula that is the signature of our species. CT scans of the fibula and tibia of LB1 and a sample of small-bodied modern humans (N=10) were used to analyze cross-sectional geometric (CSG) properties (e.g., cortical area and polar section modulus, Zp) of the tibia and fibula at midshaft. These new data were added to the much larger sample published by Marchi (2007), which included modern humans, chimpanzees, gorillas, orangutans and gibbons. External contours of additional fossils of the genus Homo (e.g., OH 35, KNM-WT-15000) were also examined in order to evaluate when the modern condition arose during the course of human evolution. Results indicate that LB1 manifests tibial/fibular robusticity indistinguishable from that of modern humans. Analysis of external contours suggests that a gracile fibula arose relatively early in human evolution and was already in place by ~1.5 mya. Although analysis of hindlimb vs. forelimb CSG of LB1 suggested a diverse locomotor repertoire (Jungers et al., 2009), this study emphasizes the importance of habitual bipedalism in H. floresiensis. This work was supported by grants from the Wenner-Gren Foundation, the Leakey Foundation, the National Geographic Society, and the Australian Research Council.

American journal of biological anthropology, Nov 16, 2021

The 85th Annual Meeting of the American Association of Physical Anthropologists, Atlanta, GA, 2016

Journal of Anatomy, Jun 25, 2022

American journal of biological anthropology, Jan 19, 2023

Journal of Morphology, Jun 20, 2016

Journal of Human Evolution, Aug 1, 2015

Journal of Human Evolution, Dec 1, 2020

International Journal of Osteoarchaeology, Sep 1, 1999

Journal of Human Evolution, Dec 1, 2005

Homo-journal of Comparative Human Biology, 2002

Journal of Human Evolution, Jul 1, 2019

American Journal of Physical Anthropology, Jun 22, 2019

American Journal of Physical Anthropology, 2011

The International Encyclopedia of Biological Anthropology, 2018

Sergio Sergi was an Italian physical anthropologist. His studies dealt mainly with anthropology a... more Sergio Sergi was an Italian physical anthropologist. His studies dealt mainly with anthropology and human biology, though they ranged from primatology, to comparative anatomy, to anthropometry and to palaeoanthropology. Sergio Sergi is known for his interpretation of human evolution, seen as a succession of “cicli di forme” (shape cycles) referring to the shape of the skull. He was also in favour of a “pre-Neanderthal” hypothesis concerning modern human origins. His works in anthropology are acknowledged worldwide and they are still cited in the scientific literature, in particular his monographs on the skulls of Monte Circeo, Saccopastore 1 and Saccopastore 2. He expanded the traditional areas of anthropology by extending the research to all organic systems, including the limbs, the tegumental system, the muscles of facial expression, the mechanism of respiration of anthropoids, and with systematic research on the spinal cord of chimpanzee.

For decades, scientists have relied on the concept of mobility in describing activity patterns of... more For decades, scientists have relied on the concept of mobility in describing activity patterns of past and present human populations. Population-level comparisons have traditionally sought to demonstrate differential mobility (e.g., logistical or residential) amongst Pleistocene or Holocene Homo groups, using this as a basis for inferring convergent or contrasting adaptive behavior. For example, shifting from a hunter-gatherer to a more sedentary agricultural subsistence strategy generally has been associated with a relative decline in mobility associated with the latter. Substantial efforts have been devoted towards inferring which musculoskeletal adaptations best reflect such a potential shift in mobility. The central role of bipedalism in human locomotion predisposes lower limb musculoskeletal anatomy to feature prominently in these inferences, although it is important to note that expressions of mobility in other areas of the postcranium (e.g., the upper limb) are gaining traction in the field when studying select populations (e.g., coastal or island groups). It is problematic that often mobility is not defined a priori in precise enough terms to facilitate comparability of results across studies. Typically, some derivation of an ethnographic definition of mobility is adopted, whether explicitly recognized or not (e.g., populations with greater mobility travel farther than populations with lesser mobility). Usually, in applying the ethnographic definition, unstated motivations for travel focus on resource acquisition or intergroup relationships (e.g., trading).

Previous research on the transition from hunting and gathering to production economy has suggeste... more Previous research on the transition from hunting and gathering to production economy has suggested some general trends in past populations, i.e. decreased diaphyseal robusticity, increased cross-sectional circularity and decreased sexual dimorphism in the lower limb bones (femur and tibia), generally explained as a consequence of decreased levels of mobility. Previous results from the study of the Ligurian Neolithic populations from North-Western Italy (6th millennium BP) provide an exception to these trends. In particular, the Ligurian Neolithic lower limb robusticity and diaphyseal shape reflect high levels of terrestrial mobility throughout a rugged terrain. These results argue in favour of the growing consensus that the Neolithic transition was a region-specific process. In this work we expand the sample to include remains from caves from the same area, all within the same pastoral system, and extend the analysis to include the fibula. These new results show that the diaphyseal morphology of the Ligurian sample is more similar to highly mobile European Late Upper Palaeolithic and Mesolithic populations. Furthermore, the degree of sexual dimorphism for mechanical properties indicates behavioural differences between sexes, with males being more mobile than females. The results found here also indicate that inclusion of the fibula may contribute to a better understanding of past population mobility especially when it is considered in association with the tibia.

In this chapter we investigate the lower limb structural rigidity (using cross-sectional geometri... more In this chapter we investigate the lower limb structural rigidity (using cross-sectional geometric properties of the diaphyseal midshaft) within a sample of 124 individuals from the Late Upper Paleolithic, Neolithic and Iron Age from Italy, Medieval Germany, and twenty-first Century Britain (long distance runners, field hockey players, and sedentary controls). Late Upper Paleolithic, Neolithic and Iron Age samples were settled in rugged areas, whereas the other samples inhabited plain areas. The aim of this study is to assess whether fibular diaphyseal properties reflect mobility patterns or terrain properties in past populations. Both fibular rigidity and relative fibular rigidity ratio (fibula/tibia) have been analyzed. Results reveal that Late Upper Paleolithic, Neolithic and Iron Age samples show high fibular rigidity and have values of relative fibular rigidity that are most similar to modern hockey players. The relative fibular diaphyseal rigidity of hockey players has been previously explained as the consequence of their dynamic and repetitive change of direction. Late Upper Paleolithic and Neolithic individuals are thought to have been highly terrestrially mobile, while Iron Age people were probably fairly sedentary. However, all of the three groups lived in areas of uneven terrain. We concluded that fibular rigidity and relative fibular rigidity are influenced by factorsthat increase foot eversion/inversion such as frequent directional changes and uneven terrain. The results of this study suggest that inclusion of the fibula provides a valuable additional perspective that complements traditional predictions of mobility patterns based on the femur or the tibia alone.

Bone has an ability to model and remodel itself such that its distribution and material propertie... more Bone has an ability to model and remodel itself such that its distribution and material properties reflect factors occurring during the lifetime of an individual. Known factors influencing bone properties range from nonmechanical (e.g., age, sex, diet, health, and hormones) to mechanical ones (e.g., activity level and patterns). A lifetime accumulation of these inputs, therefore, should be reflected in the structure of bone diaphyses at the death of an individual. Inferring the inputs of these factors from long bone diaphyses of long dead individuals, whether Holocene agriculturalists or hunter-gatherers, or earlier human ancestors, depends in part on modern analogues being used to help identify and isolate the contributions of these factors. This chapter is both an introduction to and a synthesis of the collaborative effort that is recounted within the volume, and that is aimed at understanding the impact of human mobility as one such input to diaphyseal form.

Preface For decades, scientists have relied on the concept of mobility in describing activity pa... more Preface
For decades, scientists have relied on the concept of mobility in describing activity patterns of past and present human populations. Population-level comparisons have traditionally sought to demonstrate differential mobility (e.g., logistical or residential) amongst Pleistocene or Holocene Homo groups, using this as a basis for inferring convergent or contrasting adaptive behavior. For example, shifting from a hunter-gatherer to a more sedentary agricultural subsistence strategy generally has been associated with a relative decline in mobility associated with the latter. Substantial efforts have been devoted towards inferring which musculoskeletal adaptations best reflect such a potential shift in mobility. The central role of bipedalism in human locomotion predisposes lower limb musculoskeletal anatomy to feature prominently in these inferences, although it is important to note that expressions of mobility in other areas of the postcranium (e.g., the upper limb) are gaining traction in the field when studying select populations (e.g., coastal or island groups). It is problematic that often mobility is not defined a priori in precise enough terms to facilitate comparability of results across studies. Typically, some derivation of an ethnographic definition of mobility is adopted, whether explicitly recognized or not (e.g., populations with greater mobility travel farther than populations with lesser mobility). Usually, in applying the ethnographic definition, unstated motivations for travel focus on resource acquisition or intergroup relationships (e.g., trading).
On the other hand, an excessively narrow application of the concept of mobility, such as a mechanically-focused one, equally limits comparisons of results across studies. Not all studies would (nor should) integrate experimental approaches in order to quantify mobility. Resources necessary for the requisite acquisition of ground reaction force and kinematic data are not equally available to all researchers, and there are ethical and logistical constraints when studying human subjects. Rather, the optimal solution for defining mobility, or fully capturing its essence, should embrace a multidisciplinary approach in how the concept is applied. Despite such a long-standing and widespread reliance on the concept of mobility for reconstructing and comparing activity patterns and life histories of human populations, such an inclusive attempt at defining mobility has not yet been made.
To address this notable absence, in the spring of 2011, we organized a symposium on mobility at the 80th Annual Meeting of the American Association of Physical Anthropologists held in Minneapolis, MN. The symposium assembled an array of experts using different approaches for quantifying and comparing the effects of mobility on postcranial musculoskeletal anatomy. The symposium, and subsequent discussions, were aimed at embracing current perspectives and stimulating new ones that emphasized a holistic view of the interaction among intrinsic (i.e. skeletal) and extrinsic (i.e. environmental) factors relevant for quantifying and studying differential expression of mobility. Moreover, the symposium highlighted the importance of disentangling environmental effects some of which transcend traditional categorical groupings, such as coastal versus inland and/or mountainous versus flat terrain environments.
This volume emanates from the original symposium. It is not intended to be the final word on the concept of mobility, but we hope that it will serve as a suitable starting point from which new discussion and future work can begin (or continue), perhaps with a renewed focus on critical issues identified herein or to be expanded laterally. We also hope that this volume represents a useful advance by articulating a consensus working definition of mobility that can be widely applied in anthropological studies in order to overcome the lack of consistency in explicitly defining the concept of mobility that currently cripples the comparisons of results across studies.
There are a number of people we would like to thank, for this volume would not have materialized without the substantial efforts of many. First, we would like to acknowledge the original participants in the 2011 symposium, not all of whom were able to contribute chapters to the volume for one reason or another. The discussions that took place leading up to, during, and following the symposium helped shape this volume considerably. Thank you for your contributions in driving this effort forwards. We also would like to thank contributors to the volume who did not participate in the 2011 symposium for one reason or another. Your contributions to the collective effort have broadened its scope in new, exciting ways. Chapters were reviewed by a mix of fellow contributors, co-editors, and additional colleagues. We are indebted to everyone who assisted with reviewing the individual chapters. Thank you for your time and willingness to offer constructive suggestions. Finally, we would like to thank Janet Slobodien, Jacob Gallay, and others at Springer Press for encouraging the efforts that ultimately led to this volume. We are extremely grateful for this unwavering support throughout the entire process.

This is the first attempt to study cross-sectional geometry (using a moulding technique in combin... more This is the first attempt to study cross-sectional geometry (using a moulding technique in combination with biplanar radiography) of metacarpals II-V, metatarsals I-V, and the tibio-fibular complex at 50% length across a sample of chimpanzees, gorillas, orang-utans, gibbons, and humans and to shed some light on their relationship with locomotor behaviour. The best results were obtained comparing tibia and fibula, and metacarpals and metatarsals of the same ray. On the whole, cross-sectional characteristics of the tibio-fibular complex, metacarpal and metatarsal rays are strongly related to the locomotor behaviour of hominoids, and may be useful in elucidating locomotor adaptations of fossil specimens.

In questo studio, le caratteristiche strutturali dell’arto superiore (omero) e di quello inferior... more In questo studio, le caratteristiche strutturali dell’arto superiore (omero) e di quello inferiore (femore e tibia) sono state analizzate per ricostruire le strategie di sussitenza delle popolazione neolitiche liguri. Il metodo d’indagine utilizzato consiste nello studio della geometria delle sezione a metá diafisi dell’osso. I risultati riguardanti l’omero evidenziano un alto livello di robustezza suggerendo un uso frequente dell’arto superiore nelle attività di sussistenza. Lo studio della lateralizzazione mostra per gli uomini un’elevata lateralizzazione, associabile a frequenti attivitá unimanuali, mentre per le donne la lateralizzazione è molto bassa e associabile ad un frequente uso di macine a due mani per la macinatura dei cereali. I neolitici liguri non mostrano la riduzione nella robustezza dell’arto inferiore che è caratteristica del campione tardo neolitico di confronto, e risultano più simili, sia nei livelli di robustezza che negli indici di forma diafisaria, alle popolazioni di confronto altamente mobili del Paleolitico Superiore Recente. Inoltre, gli uomini neolitici liguri risultano molto più robusti delle donne suggerendo una marcata differenziazione dei ruoli tra i sessi. I risultati dell’analisi dell’analisi biomeccanica dell’arto inferiore suggeriscono che i neolitici liguri fossero una popolazione molto mobile su un territorio accidentato e forniscono supporto all’ipotesi basata su evidenze archeologiche che queste popolazioni conducessero attività di sussistenza prevalentemente pastorali.

ABSTRACT - The cross-sectional geometry (CSG) properties of the humerus of a sample composed of n... more ABSTRACT - The cross-sectional geometry (CSG) properties of the humerus of a sample composed of nine males and eight females from three caves located in the Finalese region (Savona, Italy) have been analysed. The comparison with a European Late Upper Paleolithic sample showed unchanged humeral robusticity in females and increased humeral robusticity in males leading to an increase in sexual dimorphism, indicating different activity levels between genders probably as a consequence of sexual division of labour. Both sexes show a more rounded humeral diaphyseal circumference and decrease of lateralization probably related to an increase in activities that stressed both limbs in a similar way. In particular, the finding of grind stone in the archaeological record seems to explain the absence of lateralization in females, which might be related to the processing of cereals. Overall CSG results furnish further evidence for the hypothesis of a prevalently pastoral economy of the Neolithic people of Western Liguria.

RIASSUNTO - Sono state analizzate le proprietà di geometria delle sezioni (CSG) in un campione composto da nove maschi e otto femmine proveniente da tre caverne della zona del Finalese (Savona, Italia). Dal confronto con un campione europeo del Paleolitico Superiore Recente risulta che la robustezza dell’omero nel campione femminile rimane invariata, mentre nel campione maschile aumenta. Ne risulta un incremento del dimorfismo sessuale, probabilmente come conseguenza della divisione del lavoro in base al sesso. Entrambi i sessi mostrano sezioni diafisarie dell’omero più circolari e una diminuzione della lateralizzazione, probabilmente legati all’aumento delle attività che impegnavano in misura simile entrambi gli arti. In particolare, il ritrovamento di macine in pietra tra i reperti archeologici sembra spiegare l’assenza di lateralizzazione nelle femmine, la quale potrebbe essere legata all’attività di macinazione dei cereali. In generale, i risultati di CSG supportano e forniscono ulteriori prove all’ipotesi di un’economia prevalentemente pastorale per le popolazioni neolitiche della Liguria Occidentale.

The cross-sectional geometry of long bones is commonly used to infer their biomechanical properti... more The cross-sectional geometry of long bones is
commonly used to infer their biomechanical
properties in investigations of past and present
primate locomotion as well as to assess intensity
and repetitiveness of physical activities, and
to estimate body mass. While cross-sectional
geometry has proved to be very useful for reconstructing
bone loading patterns, a limitation of the
technique has been that only a few cross sections
along the diaphysis can be analyzed. The advent
of virtual imaging and image processing offers
the prospect of semi automating the sectioning
and calculation of geometric properties at high
resolution. We present the morphomap package,
developed in the R environment, to extract cross
sections from long bone meshes at speci􀜪ed
intervals along the diaphysis and to calculate
two and three dimensional morphometric maps,
cross-sectional geometric parameters, and
semilandmarks on the periosteal and endosteal
contours of each cross section. We demonstrate
the validity of this computational tool by showing
that it obtains the same results as those from
manual and other computational approaches.
We then demonstrate the functionality of
morphomap in a comparison of human and
chimpanzee femora. The tool produces 61 cross
sections along each diaphysis, at increments of
1% between 20% and 80% of their biomechanical
length, automatically draws morphometric maps
and calculates the parameters described above.
The results illustrate the potential of morphomap
in identifying differences in diaphyses that can be
related to differences in locomotion and lifestyle in
living and fossil primates.

The osteology of the fore- and hind-limbs has been correlated with locomotion, posture and substr... more The osteology of the fore- and hind-limbs
has been correlated with locomotion, posture
and substrate use in primates, but less attention
has been paid to myological adaptations.
Previously we presented data on the functional
correlates of primate forearm muscle fiber
architecture variables: fascicle length (FL), physiological
cross-sectional area (PCSA) and reduced
PCSA (RPCSA). Here, we greatly expand the sample to include 9 strepsirrhine, 15 platyrrhine,
and 20 catarrhine taxa spanning the entire size
range of the order (Microcebus to Gorilla), and we
also include fiber data from the leg.
Forearm muscle mass scales with positive
allometry across all primates. Catarrhines exhibit
positive allometry in their PCSA and RPCSA
indicating that larger catarrhines have relatively
stronger forearm muscles. While PCSA and
RPCSA scale with isometry for terrestrial species,
they scale with positive allometry for arboreal
ones – thus larger arboreal primates have relatively
stronger forearms. Surprisingly, there are
no differences in the forearm architecture of
quadrupeds (QUAD) when compared to vertical
clinging and leaping/suspensory species (VCL).
All leg strength variables (mass, PCSA, RPCSA)
scale with positive allometry, and speed/stretch
measure (FL) scales with isometry across the
sample. Thus, larger primates are relatively
stronger though not more flexible/faster. There is
no other phylogenetic signal in the leg muscles.
Arboreal primates have greater leg RPCSA and
QUAD have statistically heavier leg muscles than
VCL, though they are not greater in cross-sectional
area or reduced in FL.
Thus, postural and substrate use adaptations in
strength and speed substantially differ between
the fore- and hind-limbs.
This research was funded by NSF BCS-14-40599.

Relative fibular/tibial strength has been demonstrated to be related to the degree of arboreality... more Relative fibular/tibial strength has been demonstrated
to be related to the degree of arboreality/
terrestriality in anthropoid primates. In this study
fibular/tibial strength was determined in OH 35,
a Homo habilis (or possibly Paranthropus boisei),
(1.8 myr) and KNM-WT 15000, a juvenile Homo
erectus, (1.5 myr), and was compared to modern
humans (n=79), chimpanzees (n=16), gorillas
(n=16) and orangutans (n=11). Ontogenetic
changes in fibular/tibial strength were also
analyzed due to KNM-WT 15000’s juvenile status.
Cross-sectional properties were derived from
multi-plane radiography and either CT sections
of casts (fossils) or external molds (extant). RMA
regressions were run on polar second moment
of area (J), a measure of torsional and average
bending rigidity, of the fibula against that of the
tibia for all extant species. Fossils were analyzed
using their relative deviations from each regression
line, expressed in SEE units. Great apes
differed significantly from humans in regression
line elevation, with relatively stronger fibulae. OH
35 fell in the center of the great ape distribution,
within 1 SEE of each great ape taxon, but 1.9 SEE
from humans. KNM-WT 15000 was more than
2 SEE from all great apes and within 0.6 SEE
of humans. This was not a result of his age, as
fibular/tibial strength slightly decreases with age
in humans. OH 35 has some human-like features;
however, the relative strength of the two bones
aligns the specimen with great apes, suggesting
a significant degree of arboreality. KNM-WT
15000 is demonstrated to be fully modern,
complimenting other evidence for complete
terrestrial bipedality.

It is largely held that the transition from Australopithecus to the genus Homo involved a shift i... more It is largely held that the transition from Australopithecus to the genus Homo involved a shift in overall body proportions, including a relative lengthening of the lower limb, though
the degree to which hominin limb proportions changed and the proximate causes thereof remain contentious topics. The overall poor preservation of most articular surfaces and predominately fragmentary diaphyses in the mature Dinaledi
lower limb long bone sample preclude a definitive assessment of lower limb proportions based on this material alone. The U.W. 101-1070 immature tibia is the most complete H. naledi
lower limb element recovered to date, measuring 278 mm from the eminence of the tibial spines to the distal extent of the medial malleolus, and preserving nearly the entire medial condyle. To assess proportions, we evaluated tibia medial
condylar dimensions relative to tibia maximum length in U.W. 101-1070, other fossil hominin tibiae, and an ontogenetic sample of humans, chimpanzees, and gorillas. Results indicate that the U.W. 101-1070 tibia is very long relative to joint size – markedly differing from all extant species and comparative fossil hominin tibiae. The combination of an exceptionally small tibial articular surface (like many australopiths) and moderately long tibia, in H. naledi, appears autapomorphic in the hominin fossil record. Though the specific implications of this finding
are partially dependent on the geological age and phylogenetic position of H. naledi, U.W. 101-1070 provides an example of bone length/joint size decoupling relative to the human pattern.

In this preliminary reconstruction of Homo naledi’s gait we begin with the null hypothesis that i... more In this preliminary reconstruction of Homo naledi’s gait we begin with the null hypothesis that it walked similarly to modern humans, as the overall anatomy of this extinct hominin’s lower limb, especially its foot, is mostly modern
human-like. We note the following characters as modern-like: dorsally-canting metatarsophalangeal joints facilitating toe-off, locking transverse tarsal joint implying a rigid midfoot during stance, flat subtalar joint limiting ankle pro- and supination, talocrural joint oriented orthogonally to the substrate, valgus knee, thick patellae increasing the moment arm for quadriceps femoris, and well-developed thigh muscle attachment sites throughout the femur. These characters suggest Homo naledi was welladapted to a striding bipedal gait. However, we also note the following less modern-like characters: curved pedal phalanges, low sustentaculum tali and likely a low fundamental
longitudinal arch, pronounced tubercular insertion of the pes anserinus tendon on the proximomedial tibia, long femoral neck with a marked medial encroachment of the obturator
externus, posteriorly positioned ilium relative to the acetabulum, flared iliac blades, broad lower ribcage, and characters of the lower thoracic vertebrae and lower rib suggesting robust hypaxial muscles. We offer our initial functional interpretations of the cumulative postcranial
morphology, which suggests different trunk stabilization from modern humans but is consistent with orthogrady and an obligate bipedal locomotor regime. Given the anatomy of
the upper limb, Homo naledi demonstrates coexistence of both bipedalism and climbing adaptations in one hominin taxon.

Rising Star Cave is located in the Cradle of Humankind World Heritage site near Krugersdorp in So... more Rising Star Cave is located in the Cradle of Humankind World Heritage site near Krugersdorp in South Africa. In November 2013 and March 2014 more than 1500 hominin fossil elements attributed to a new species, Homo naledi, were recovered and catalogued representing at least a dozen individuals. Only 20
out of 206 bones in the human body are not in the collection as currently represented from the excavation. The thigh and leg of H. naledi, which are represented by 121 femoral, patellar, tibial, and fibular elements, are marked by a mosaic of primitive, derived, and unique traits that are functionally indicative of a bipedal hominin capable of long distance walking and, possibly,
running. Traits shared with australopiths include a long, tall, and anteverted femoral neck, a mediolaterally compressed tibia, and a relatively circular fibular neck. Derived traits shared with Homo include a well-marked linea aspera, anteroposteriorly thick patellae, relatively long tibiae, and gracile fibulae with laterally oriented lateral malleoli. Unique features include the presence of two pillars on the superior aspect of the femoral neck and a strong distal insertion of
the pes anserinus on the tibia. The mosaic morphology of the H. naledi thigh and leg appears most consistent with a species
intermediate between Australopithecus spp. and H. erectus and, accordingly, may offer insight into the nature of the Australopithecus-Homo morphological transition. These fossils also expand the morphological diversity of the Homo lower limb, perhaps indicative of locomotor diversity in our genus.

The fibula has rarely been considered in comparative morphological studies. The bones normally us... more The fibula has rarely been considered in comparative morphological studies. The bones normally used to investigate early hominin locomotor behavior are the largest bones of the hindlimb, femur and tibia. The reason for this choice is probably due to the relatively minor role of the fibula in carrying mechanical loads. However differences in morphology (and inferred function) of the fibula between human and non-human great apes, and within non-human great apes, have been noted in the past and related to differences in positional behavior. Recent research (Marchi, 2007; Marchi and Shaw, 2011) have pointed out the correlation present between diaphyseal structural properties of the fibula and locomotor behavior in living hominids (i.e. Pongo, Gorilla, Pan and Homo), and its possible application to inferring early hominin locomotor behavior. The problem with the method proposed in these studies is the extreme rarity of complete fibular diaphyses in the early hominin fossil record. However, distal fibular fragments are present in the fossil record. In particular, five distal fibulae of Australopithecus afaresis (i.e. AL 288-1at, AL 333-1a, AL 333-1b, AL 333-85, AL 333w-37) from the Hadar region of Ethiopia are available. Several morphological traits in the distal part of the fibula have been used in the past to infer locomotory adaptations and in particular the degree of arboreality in fossil hominins (Stern and Susman, 1983). However, the descriptions of these traits are often qualitatite. In this preliminary research articular measurements of the distal fibula of living hominids (Pongo, Gorilla, Pan and Homo, N = 107) are quantified. Besides articular area and breadth of the fibulotalar articular surfaces (i.e. proximal and distal), quantitative analysis is provided here of: 1. the angles formed by the fibulotalar articular surfaces with the longitudinal axis of the fibula; 2. the angle between the proximal portion of the fibulotalar articular surface and the subcutaneous triangular area of the fibula, which was hypothesized to be related to the degree of arboreality in great apes (Stern and Susman, 1983). Results show that the morphological characteristics of the distal fibula bear signals correlated with different locomotor behaviors particularly useful to distinguish between bipedal and non-bipedal hominids. The application of this method to the five distal Au. afarensis fibulae available shows how these morphological traits can be added to the ones normally investigated by palaeoanthropologists to better understand early hominin locomotory behavior.

In questo studio, le caratteristiche strutturali dell’arto superiore (omero) e di quello inferior... more In questo studio, le caratteristiche strutturali dell’arto superiore (omero) e di quello inferiore (femore e tibia) sono state analizzate per ricostruire le strategie di sussitenza delle popolazione neolitiche liguri (LIG). Il metodo di indagine utilizzato consiste nello studio della geometria delle sezione a metá diafisi dell’osso. I risultati riguardanti l’omero evidenziano un livello di robustezza non dissimile da quello dei cacciatori paleolitici e significativamente più elevato rispetto alle popolazioni contemporanee, cosa che suggerisce un uso frequente dell’arto superiore nelle attività di sussistenza. Lo studio della lateralizzazione suggerisce che queste attività di sussistenza fossero radicalmente diverse nei due sessi. Infatti, i maschi presentano una elevata lateralizzazione, associabile all’uso delle asce in pietra verde così frequenti nei livelli neolitici. Al contrario, le femmine presentano un livello di lateralizzazione significativamente più basso del normale, associabile ad un frequente uso di macine a due mani per la macinatura dei cereali. Per quanto riguarda l’arto inferiore, i LIG non mostrano la riduzione nella robustezza dell’arto inferiore che è invece caratteristica del campione tardo neolitico utilizzato come confronto. I LIG risultano invece più simili, sia nei livelli di robustezza che negli indici di forma diafisaria, alle popolazioni di confronto altamente mobili del Paleolitico Superiore Recente. Inoltre, i maschi LIG risultano molto più robusti delle femmine suggerendo una marcata differenziazione dei ruoli tra i sessi. In definitiva, i risultati dell’analisi della robustezza meccanica e degli indici di forma diafisaria dell’arto inferiore suggeriscono che i LIG fossero una popolazione molto mobile su un territorio accidentato e forniscono supporto all’ipotesi basata su evidenze archeologiche che i LIG conducessero attività di sussistenza prevalentemente pastorali.