A Geometric Morphometric Study of Sexual Dimorphism in the Human Hip Bone. Heather Isobel Robertson Bachelor of Arts, Simon Fraser University, 2004

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1 A Geometic Mophometic Study of Sexual Dimophism in the Human Hip Bone by Heathe Isobel Robetson Bachelo of Ats, Simon Fase Univesity, 2004 A Thesis Submitted in Patial Fulfillment of the Requiements fo the Degee of MASTER OF ARTS in the Depatment of Anthopology Heathe Isobel Robetson, 2013 Univesity of Victoia All ights eseved. This thesis may not be epoduced in whole o in pat, by photocopy o othe means, without the pemission of the autho.

2 ii Supevisoy Committee A Geometic Mophometic Study of Sexual Dimophism in the Human Hip Bone by Heathe Isobel Robetson Bachelo of Ats, Simon Fase Univesity, 2004 Supevisoy Committee D. Helen Kuki, (Depatment of Anthopology) Supeviso D. Lisa Gould, (Depatment of Anthopology) Depatmental Membe

3 iii Abstact Supevisoy Committee D. Helen Kuki, Depatment of Anthopology Supeviso D. Lisa Gould, Depatment of Anthopology Depatmental Membe The pupose of this study was to use geometic mophometics (GM) to investigate the elationships between non-metic taits of the human hip bone: the geate sciatic notch (GSN), the vental ac (VA), the subpubic contou (SPC), and the ischiopubic amus idge (IPRR), estimated skeletal sex, and shape. Fifty-nine undocumented left hip bone specimens wee visually assessed fo skeletal sex using ecognized standads of sex estimation fo the GSN (Buiksta and Ubelake, 1994). The VA, SPC, and IPRR wee assessed accoding to Klales et al., (2012). The Non-metic taits wee scoed on a five-scale scheme. Skeletal sex was classified as eithe male, possible male, indeteminate sex, possible female, o female. Thee-dimensional compute models wee ceated of the hip bones using the NextEngine 3D desktop suface scanne. Thity landmaks wee selected to epesent the hip bone in thee-dimensional shape fo GM analysis. Twenty-seven of the selected landmaks wee eliable accoding to suggested digitizing eo measuements. The apex of the auicula suface, the acuate eminence, and the anteio gluteal line wee the least pecise in the test fo digitizing eo. Geometic mophometic analysis of the compute models wee pefomed using MophoJ softwae. Pincipal component analysis identified the pattens of hip bone shape within the sex categoies. A Pocustes ANOVA and a Speaman's coelation tested the significance between hip bone shape and estimated skeletal sex, and between hip bone shape and non-metic tait mophology. Pattens of hip bone shape in the ischium could not be identified by sex, howeve sex diffeences wee identified in ischium size. Pattens of hip bone shape in the whole hip bone, segmented ilium and segmented pubis wee distinguishable by lage sex goups (males = male and possible male categoies; females = female and possible female categoies). Shape pattens alluded to diffeences between females and possible females,

4 iv howeve, shape pattens did not distinguish males fom possible males. Individuals of indeteminate sex shaed simila hip bone shapes as males and wee theefoe included in that lage sex goup. Hip bone shape was also coelated with GSN, SPC, IPRR, and VA. Howeve, the stength of the coelation diffeed between non-metic taits and cetain components of hip bone shape. The GSN and SPC had the stongest coelation (p=<0.01) with the whole hip bone, the ilium and the pubis at distinguishing between lage male and female sex goups. The IPRR, and GSN had the stongest coelation (p=<0.01) with the pubis at distinguishing females and possible females. The esults of the study suggest that non-metic taits can discen pattens of female shape bette than pattens of male shape. Futhe eseach into discening pattens of male hip bone shape and non-metic tait vaiation using GM is suggested. The esults of the study also suggest that pattens of pubis shape might exist among females and could be identifiable using pubis non-metic tait scoes. This esult lends cedence to the pactice of estimating sex on a five-scale gadient athe than on a male/female dichotomous division, in ode to captue the mophological vaiation of female hip bone bette.

5 v Table of Contents Supevisoy Committee... ii Abstact... iii Table of Contents... v List of Tables... viii List of Figues... ix Acknowledgments... xii Dedication... xiii Chapte 1 : Intoduction and Backgound Intoduction Theoy of skeletal sex in human osteology How to Categoize sex Sex Estimation Methods Sex Estimation Using Geometic Mophometics Significance of Study Chapte 2 : Mateials and Methods Mateials Methods Sex estimation NextEngine lase scanne Landmak placement Geometic mophometic and statistical analysis Hypotheses... 43

6 vi Chapte 3 : Results Sex Estimation and Non-Metic Tait Scoes Inta-Obseve Eo Pocustes Analysis of Size and Shape Pincipal Component Analysis Whole bone dataset Ilium dataset Ischium dataset Pubis dataset Ilium-ischium dataset Ilium-pubis dataset Ischium-pubis dataset Summay of PCA esults Speaman's Coelation Summay of Results Chapte 4 : Discussion The Ischium The Ilium The Pubis Non-Metic Taits and Hip Bone shape Chapte 5 : Conclusions and Futue Reseach Refeences Cited Appendix A: Specimens and non-metic tait evaluation, aw data

7 vii Appendix B: Pincipal Component Analysis, Whole bone, Pocustes Coodinates Appendix C: Pincipal Component Analysis, Ilium, Pocustes Coodinates Appendix D: Pincipal Component Analysis, Ischium, Pocustes Coodinates Appendix E: Pincipal Component Analysis, Pubis, Pocustes Coodinates Appendix F: Pincipal Component Analysis, Ilium-Ischium, Pocustes Coodinates Appendix G: Pincipal Component Analysis, Ilium-Pubis, Pocustes Coodinates Appendix H: Pincipal Component Analysis, Ischium-Pubis, Pocustes Coodinates Appendix I: Speaman's Coelation fo the Whole Bone Dataset Appendix J: Speaman's Coelation fo Ilium Dataset Appendix K: Speaman's Coelation fo the Ischium Dataset Appendix L: Speaman's Coelation fo the Pubis Dataset Appendix M: Speaman's Coelation of Ilium-Ischium Dataset Appendix N: Speaman's Coelation of the Ilium-Pubis Dataset Appendix O: Speaman's Coelation of the Ischium-Pubis Dataset

8 viii List of Tables Table 2.1: Mophological desciption of non-metic tait scoes. [adapted fom Klales et al., (2012) and Buiksta and Ubelake (1994)] Table 2.2: Landmak types and definitions Table 3.1: Summay of non-metic tait scoes and sex estimation Table 3.2: Mean Pocustes landmak standad deviation (mm) fo the fist and second episodes of landmak placement Table 3.3: Pocustes ANOVA calculating measuement eo fo centoid size and object shape. Bolded values indicate significance at a 0.05 alpha level Table 3.4: Pocustes ANOVA esults fo log centoid size and Pocustes distances (shape) gouped by non-metic tait and sex estimation scoes fo all datasets. Bolded values indicate significance at a 0.05 alpha level Table 3.5: Pincipal components etained fo analysis Table 3.6: Speaman coelation testing the significance of non-metic tait scoe and estimated sex on selected pincipal components. Italicised values indicate a significant coelation at a 0.05 alpha level. Bolded values indicate a significant coelation at a 0.01 alpha level

9 ix List of Figues Figue 1.1: Most sexually dimophic egions of the human hip bone. [Adapted fom Buiksta and Ubelake, 1994:17] Figue 2.1: Five scale scoing system fo the subpubic contou (top), the ischiopubic amus idge (middle) and the vental ac (bottom). Scoes 1 and 2 in each image epesents typical female mophology, scoe 3 epesents indeteminate mophology, scoes 4 and 5 epesent male mophology. [Repoduced fom Klales et al., 2012:4] Figue 2.2: Five scale scoing system fo the geate sciatic notch. Scoe 1 epesents typical female mophology, scoe 2 epesents indeteminate mophology, scoes 3, 4 and 5 epesent male mophology. [Repoduced fom Buiksta and Ubelake, 1994:18] Figue 2.3: Image "A" the fist hip bone scan position paallel to the NextEngine PatGippe. Image "B" the second hip bone scan position pependicula to the PatGippe Figue 2.4: Landmak placement and wiefame gaph compaison. A: MophoJ wiefame image Axis 1 vs. 2. B: Landmak opaque image with landmaks; anteio view. C: MophoJ wiefame image Axis 1 vs. 3. D: Landmak opaque image with landmaks; posteio view Figue 2.5: Landmaks gouped into hip bone egions, ilium in oange, ischium in blue, and pubis in ed Figue 2.6: Illustation of Pocustes Supeimposition. Image "A" aw landmak configuations data. Image "B" centeed configuations. Image "C" centeed and scaled configuations. Image "D" centeed, scaled and otated configuations Figue 3.1: Wiefame gaphs illustating the shape changes on the PC1 axis of the whole bone dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC1 axis. B: the shape at the negative end of the PC1 axis Figue 3.2: Wiefame gaphs illustating the shape changes on the PC2 axis of the whole bone dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC2 axis. B: the shape at the negative end of the PC2 axis Figue 3.3: Distibution of specimens fom the whole hip bone dataset categoized by estimated sex. PC1 and PC

10 Figue 3.4: Wiefame gaphs illustating the shape changes on the PC1 axis of the ilium dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC1 axis. B: the shape at the negative end of the PC1 axis Figue 3.5: Wiefame gaphs illustating the shape changes on the PC2 axis of the ilium dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC2 axis. B: the shape at the negative end of the PC2 axis Figue 3.6: Wiefame gaphs illustating the shape changes on the PC4 axis of the ilium dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC4 axis. B: the shape at the negative end of the PC4 axis Figue 3.7: Distibution of specimens fom the ilium dataset categoized by estimated sex. A: PC1 and PC2. B: PC1 and PC Figue 3.8: Wiefame gaphs illustating the shape changes on the PC1 axis of the ischium dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC1 axis. B: the shape at the negative end of the PC1 axis Figue 3.9: Wiefame gaphs illustating the shape changes on the PC2 axis of the ischium dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC2 axis. B: the shape at the negative end of the PC2 axis Figue 3.10: Distibution of specimens fom the ischium dataset categoized by estimated sex, PC1 and PC Figue 3.11: Wiefame gaphs illustating the shape changes on the PC1 axis of the pubis dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC1 axis. B: the shape at the negative end of the PC1 axis Figue 3.12: Wiefame gaphs illustating the shape changes on the PC2 axis of the pubis dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC1 axis. B: the shape at the negative end of the PC1 axis Figue 3.13: Wiefame gaphs illustating the shape changes on the PC3 axis of the pubis dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC3 axis. B: the shape at the negative end of the PC3 axis x

11 Figue 3.14: Distibution of specimens fom the pubis dataset categoized by estimated sex. A: PC1 and PC2. B: PC2 and PC Figue 3.15: Wiefame gaphs illustating the shape changes on the PC1 axis of the ilium-ischium dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC1 axis. B: the shape at the negative end of the PC1 axis Figue 3.16: Wiefame gaphs illustating the shape changes on the PC2 axis of the ilium-ischium dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC2 axis. B: the shape at the negative end of the PC2 axis Figue 3.17: Distibution of specimens fom the ilium-ischium dataset categoized by estimated sex, PC1 and PC Figue 3.18: Wiefame gaphs illustating the shape changes on the PC1 axis of the ilium-pubis dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC1 axis. B: the shape at the negative end of the PC1 axis Figue 3.19: Wiefame gaphs illustating the shape changes on the PC2 axis of the ilium-pubis dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC2 axis. B: the shape at the negative end of the PC2 axis Figue 3.20: Distibution of specimens fom the ilium-pubis dataset categoized by estimated sex. PC1 and PC Figue 3.21: Wiefame gaphs illustating the shape changes on the PC1 axis of the ischium-pubis dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC1 axis. B: the shape at the negative end of the PC1 axis Figue 3.22: Wiefame gaphs illustating the shape changes on the PC2 axis of the ischium-pubis dataset. Dak blue lines epesent shape change; light blue lines epesent the mean shape. A: the shape at the positive end of the PC2 axis. B: the shape at the negative end of the PC2 axis Figue 3.23: Distibution of specimens fom the ischium-pubis dataset categoized by estimated sex, PC1 and PC xi

12 Acknowledgments xii Thee ae many people I wish to acknowledge who wee involved in the success of this thesis both diectly and indiectly. I wish to thank my family and my fiends who suppoted and encouaged my decision to commute to a Univesity ove 100km away fom home. I especially acknowledge the patience of D. Douglas Ross and Anika Robetson who lived with my many incanations thoughout this pocess. To those in the Depatment of Anthopology at the Univesity of Victoia who inspied and instucted me, I thank you fo you wisdom and fo you knowledge. I especially wish to acknowledge the insights of D. Helen Kuki and D. Lisa Gould that guided me along this jouney. Thanks also to Shannon Wood and D. Babaa Winte in the Depatment of Achaeology at Simon Fase Univesity, and D. Danmei Liu fom the Cente fo Hip Health and Mobility who in thei diffeent ways inspied, pepaed, and encouaged me to begin this jouney. This eseach would not have been possible if not fo those who helped facilitate it. The Depatment of Cellula and Physiological Sciences at the Univesity of Bitish Columbia, thanks to D. Claudia Kebs, Ciaan Connolly, Ein Gloeden, Heathe Fanden, and Alan Gilmou, povided the time and the specimens needed to see the fuits of this eseach.

13 xiii Dedication Fo: Doug and Anika; Julia and Sasha

14 1 Chapte 1 : Intoduction and Backgound 1.1. Intoduction Sex estimation and categoization is easily accomplished in human osteology when thee ae clea size and shape diffeence between the hip bones of males and females (Buiksta and Ubelake, 1994; Listi, 2010; Phenice, 1969; Walke, 2005). Poblems occu in sex estimation when thee is little sexual dimophism within a population (Rosenbeg, 2002). When sexual dimophism is limited, it has the potential to conflate sex identification by making size diffeences and mophological sex taits indistinguishable, esulting in "possible" o "indeteminate" sex deteminations if applying visual methods to estimate sex (Buiksta and Ubelake, 1994). Regadless of the level of size dimophism in a population, shape-based sex diffeences ae etained because obstetic capacity is constant in females (Gustafson and Lindenfos, 2004; Kuki, 2007, 2011, 2013; Ridgeway et al., 2011; Tague, 2000). Theefoe, sex-based shape diffeences should be discenible even if sexual dimophism and non-metic tait discimination ae limited. The pupose of this eseach is to gain new insight into human hip bone mophology and its elationship with non-metic sex taits using a new method of analysing shape diffeences in bone, geometic mophometics (GM). This eseach has two goals. The fist goal is to investigate the mophological chaacteistics that distinguish sex in whole and patial hip bone shapes using GM analysis. This goal is impotant fo undestanding the vaiations of hip bone shape among males and females in both whole and patial hip bones. The second goal of this eseach is to exploe the elationships between non-metic tait mophologies and hip bone shape in whole and

15 patial hip bones. It is impotant fo boadening ou undestanding of non-metic tait 2 pattens among male and female goups in ode to gain new insights into using nonmetic taits when estimating the sex of individuals fom populations with limited sexual dimophism between males and females, o between populations. Sex diffeences in human osteology ae pedicated by anatomical diffeences in the human skeleton, such as non-metic taits and epoductive capability (Buiksta and Ubelake, 1994; Gella, 2005; Phenice, 1969; Walke, In ode to undestand how mophological vaiability in humans could influence sex diffeences in the human hip bone it is impotant to eview the evolutionay life histoy of the hip bone (Buiksta and Ubelake, 1994; Nodbladh and Yates, 1990). The shape of human hip bone is a poduct of bipedalism, and the shape of the human female pelvis is a negotiation of the biomechanical needs of bipedalism and the obstetic capacity to give bith to lage bained human infants (Gabowski et al., 2011). Envionmental adaptation geneates population vaiation in the size of the hip bone, wheeas genetic vaiations in the fom of timing and ate of adolescent gowth influence hip bone size and shape vaiation among individuals. Evolutionay, envionmental, and genetic factos ae also impotant to conside when conceptualizing of sexual dimophism in the human skeleton. Skeletal sex is undestood as an extension of biological sex, is obsevable in phenotypic and genotypic taits, and is categoized dichotomously (Gelle, 2005). Howeve, when consideing the factos that contibute to hip bone mophology, the dichotomous categoization might not epesent that complexity adequately (Blackless et al., 2000; Fausto-Steling, 2000; Nodbladh and Yates, 1990). A ange of sex categoies might be a bette appoach to epesent both sex and shape vaiation.

16 3 The conceptualization of sex is evident in the methods human osteologists use to estimate sex. Odinal methods of sex estimation involve visually assessing skeletal mophology and scoing, o anking, non-metic taits such as the vental ac, subpubic contou, ischiopubic amus idge, and the geate sciatic notch along a shape continuum fom hype-male to hype-female (Buiksta and Ubelake, 1994; Byes, 2002; Klales et al., 2012; Phenice, 1969; Walke, 2005). Metic methods of sex estimation ely on absolute measuements to detemine sexually dimophic size and shape (Aun et al., 2012; Luo, 1995; Washbun, 1948). Both methods have an aay of stengths that make them suitable fo estimating sex on the human hip bone, howeve, they also have thei limitations. A common limitation found in both sex estimation methods is emaining useful o applicable when estimating sex fom fagmented hip bones (Aun et al., 2012; Bůžek, 2002; Buiksta and Ubelake, 1994; Roges and Saundes, 1994). Geometic mophometics (GM) is a elatively new method of investigating sex diffeences using landmaks to epesent object shape and size as Catesian coodinates in tangent space. Applied to the undestanding of sex-based shape diffeences, GM combines the stengths of odinal sex estimation methods as it captues bone shape vaiation, and metic sex estimation methods as it captues bone size and Euclidian distances (Gómez-Valdés et al., 2012; Petoius et al., 2006; Slice, 2007; Zelditch et al., 2004). Geometic mophometics also addesses the limitations of odinal methods by being a moe objective assessment of shape than visual assessments, and the limitations of metic methods by being a moe accuate measue of sex. Fo these easons, GM is an ideal technique to use to investigative sex-based shape diffeences in the human hip bone as a whole and in isolated shapes. Until now GM has been used to detemine sex

17 dichotomously, howeve, this eseach will attempt to isolate the sex-based shape 4 diffeences on a five-scale sex continuum Theoy of skeletal sex in human osteology Accoding to Gelle (2005), skeletal sex is conceived of as a natual biological division within a species fo the pupose of epoduction, is obsevable in phenotypic and genotypic taits, and is categoizable into binaies. Gelle goes on to citique the analytical igidity ceated by a biologically defined sex binay, a sentiment that is shaed by a few othe authos (Nodbladh and Yates, 1990; Hollimon, 2011; Søensen, 2000), and poposes analysing sex as sepaate fom biology. The esult is a new concept of gende theoy that includes sexuality to illustate the multifaceted movement of societal oles, sexuality, and identity that ae independent of biology (Gelle, 2005). Although Gelle's poposed view of gende povides a fluid and etospective theoetical foundation, it shifts the gaze away fom the aguments that eview and citique dichotomous sex classification in human osteology and in biology (Bleche and Eickson, 2007; Nodbladh and Yates, 1990; Sitek et al., 2012). Aguably, a continuum of sex categoization poposed by Nodbladh and Yates (1990) and Bleche and Eickson (2007) is a justifiable concept of skeletal sex. Using Gelle's model of how sex is conceived of in human osteology, I will outline an altenative view of how sex can be conceived of in biology, not as a binay, but as a continuum. Evolutionay and adaptive foces mitigate size and shape diffeences in the hip bone athe than define natual dimophism of the human species; phenotypic and genotypic taits do not sepaate the sexes clealy in

18 biology, and ae less clea in human osteology; and categoization of sex needs confident teminology in ode to be divided along a continuum Repoduction, evolution, and adaptation In Gelle's citique of how sex is conceived of in human osteology, she claims that human osteologists peceive biology as unchanging, subjected to westen ethnocentism, and positivistic epistemologies. As such, she divoces sex fom biology by suggesting that sex, like gende, is a cultual constuct in the way science, medicine, and society take the binay division of sex fo ganted (Gelle, 2005). This idea pesists among some human osteologists in the way sex is intepeted and categoized, but it is sometimes tempeed with the ecognition that sex is also vaiable between populations (Byes, 2002; Mays, 2010; Sofae, 2006; White, 2000). Othe human osteologists suggest altenative methods to the classic division of sex as binaies (Agawal, 2012; Hollimon, 2011; Klales et al., 2012; Nodbladh and Yates, 1990). If we, human osteologists, deepen ou peception of how "biological sex" came to be in moden humans by eviewing the evolutionay life histoy of the hip bone, we can begin to see that biology and sex ae not static, but dynamic. Sexual dimophism of the human hip bone is a eflection of the epoductive mechanics of patuition and body size in a lage bained bipedal pimate (Asuaga and Caeteo, 1994; Gabowski et al., 2011; Lovejoy, 2005; Plavcan, 2011; Tague, 1991). Habitual bipedalism is possible due to changes in the shape of the sacum, spine, and hip bones to accommodate the muscles that maintain an upight postue (Lovejoy, 2005). Ove time, the mophology of the pelvis (aticulated sacum, coccyx, and hip bones) widened anteo-posteioly to accommodate the expanding hominin bain

19 6 (Lovejoy, 2005). In humans, the biomechanical demands of bipedalism on the human hip bone favou a naow pelvis, and the cephalo-pelvic demands of bithing a lage bained baby encouage a wide female pelvic complex (Gabowski et al., 2011; Lovejoy, 2005). Togethe, these two foces have geneated a hip bone mophology that is uniquely human. In a epoductive famewok, dimophism of the hip bone is clea, females must give bith and the hip bone shape must accommodate this, males do not give bith so the hip bone shape is fee to confom to only the biomechanical needs of bipedalism. Howeve, dimophism of the hip bone becomes moe complex when factoing in theoies of mate selection and envionmental adaptation. The measue of sexual dimophism in body size between males and females of a species is believed to be influenced by the patten of mate competition and mate selection adopted by that species (Badyaev, 2002; Plavcan, 2011). Fo example, among mixed-sex pimate goups, whee males compete fo mating pivileges, males tend to be lage than females in body size and seconday sex chaacteistics especially among anthopoids (Badyaev, 2002; Plavcan, 2011). Body size diffeences among "monogamous pimates," pimates who tend to fom long-tem mating patneships with one mate and aguably include humans, ae less contasting between males and females than among mixed-sex pimate goups. One possible eason fo this is that the males ae not competing fo mating pivileges, but athe males and females ae selecting desiable taits in the opposite sex that lead to vaiations in body size selection in both sexes (Plavcan, 2011). Plavcan (2011) suggests that low female metabolic demands duing pegnancy, and high fecundity due to a younge epoductive age ae desiable taits found in smalle sized females (Gluckman and Hanson, 2006; Nettle, 2002b). Howeve, mate selection is not

20 7 the only facto to influence body size vaiations. Adaptation to diffeences in climate can also influence body beadth and size, which ae eflected in hip bone shape diffeences in human populations because of themoegulation (Ruff, 1991; 2002). Wide and shote pelvic complexes ae geneally chaacteistic of colde climates because they have less suface aea fo heat exchange, wheeas talle and naowe hip bones have moe suface aea to facilitate heat loss and ae geneally chaacteistic of wame climates (Ruff, 1991; 2002). By acknowledging the complexities of change that has taken place in human evolution, we can see that dimophism, as it manifests in the skeleton, has a complicated past ooted in biology. Dimophism is a poduct of the epoductive mechanism of childbith in females and pattens of mate selection, while envionmental adaptation geneates size and shape vaiability within human females and males. Size and shape vaiability within sex goups does not pose a pima facie poblem fo sex estimation until the mophology of one sex goup esembles the mophology of the othe sex goup, ceating an ovelap between the sexes (Bidmos et al., 2010; Phenice, 1969; Steyn and Patiquin, 2009; Rosenbeg, 2002; Washbun, 1948). One way of investigating the male/female ovelap of size and shape is to undestand othe souces of size and shape vaiability in the hip bone Genotypic and phenotypic sex taits Genotypic and phenotypic souces of hip bone size and shape vaiation can contibute to male/female mophological ovelap. Typically, genital fom and function, pimay sex chaacteistics, ae deived fom allosomal combinations (Stone, 2008).

21 8 Ovaies develop fom an XX allosome pai while testes develop fom an XY combination (Bleche and Eickson, 2007; Fausto-Steling, 2000). Seconday sex chaacteistics develop duing adolescence, and endocine secetions fom sex ogans goven thei development (Bleche and Eickson, 2007; Wilson, 1981). Typical allosome combination, ceating typical gonad fom and function, lead to typical skeletal sex chaacteistics, such as a lage and naowe hip bone in males and a smalle and wide hip bone in females. Howeve, in ae cases, multiple chomosomes combine in the fetilized ovum, o thee is an absence of an autosome afte fetilization, which affect gonadal development and endocine secetion such as Tune Syndome (XO) o Klinefelte Syndome (XXY). The endocine changes elated to chomosomal changes influences the shape of the hip bone away fom the typical phenotype (Fausto-Steling, 2000; Stone, 2008). It has been suggested that andogens influence the shape of the male hip bone duing adolescence, and the pesence of andogen eceptos in females could influence the shape of the female hip bone close to a male shape (Sitek et al., 2012; Iguchi et al., 1995). In animal tials, the absence of andogen poduction due to castation esulted in female like hip bones (Iguchi et al., 1995; Uesugi et al 1992). Howeve, new eseach into the genetic influences of the development of seconday sex chaacteistics has suggested that sex-detemining factos in the allosomes, and possibly in the autosomes, is what stimulates the development of sex chaacteistics into male and female foms athe than simply endocine secetions deived fom allosomes combination (Bleche and Eickson, 2007). This could explain why individuals with Tune Syndome, who have limited ovaian function and endocine levels, develop phenotypically female chaacteistics. It could also explain why

22 individuals who ae XXY and have limited endocine function, poduce a smalle and 9 wide hip bone, simila to the female shape, in spite of having a XY allosome combination (Blackless et al., 2000; Bleche and Eickson, 2007; Uesugi et al., 1992). Sex-detemining factos also explain why individuals with typical sex chomosome paings can develop intesexed phenotypes (Bleche and Eickson, 2007). The most common type of phenotypic intesexuality, congenital adenal hypeplasia (CAH), occus in oughly 1.5 pecent of the population (Fausto-Steling, 2000). Congenital adenal hypeplasia causes the gowth of masculine like genitalia in infants with XX chomosomes (Blackless et al., 2000). The factos that pomote masculine like genitalia in XX individuals could vey likely influence the shape of the hip bone. Pimay sex chaacteistic mophologies could be the esult of moe male sex-detemining facto in the individual, which could in tun influence the mophology of seconday sex chaacteistics including the hip bone. The degee to which the hip bone could change in intesexed individuals and individuals with gonadal dysgenesis is unknown, it could esemble a moe masculine hip bone o it could esemble a female/male hybid shape if obstetic capacity is maintained in females. Sex-detemining factos could be an impotant cause of mophological vaiation that explains male/female ovelap of hip bone non-metic taits. The combined pevalence of Tune Syndome, Klinefelte Syndome, and CAH intesexuality is oughly 2% of the population. In the hip bone that could mean 2% of all skeletal specimens could be intesexed and possess a hip bone mophology that is unique to the typical "male" o "female." In the most accuate of cuent human osteological methods thee is a 2% accuacy eo that is attibuted as an atifact of method quality esulting in

23 10 hip bone misclassification (Bůžek, 2002). Howeve, it could also be the esult of tying to fit thee mophological types into two categoies. It is not the goal of this thesis to uncove the causes of hip bone misclassification o intesexuality, howeve, it is impotant to conside what might be occuing in 2% of the population when intepeting the accuacies of sex estimation methods that will be intoduced late in this chapte. Sitek and colleagues (2012) found a patten of hip bone shape in female to male tanssexuals that was diffeent fom non tanssexual females. Individual homonal vaiance could be one of the causes of hip bone shape vaiance due to sex detemining facto (Bleche and Eickson, 2007; Sitek et al, 2012). The biological pedicto of sex is theefoe moe complicated than it once appeaed and contibutes to the dynamic popeties of sex as biology. Bleche and Eickson (2007) also suggest that sex-detemining factos influence sex and gowth homones of males and females of typical chomosomal sex to poduce population specific mophological sex chaacteistics. This would account fo the vaiation in hip bone size and shape seen acoss populations that lead to the ovelap of hip bone size and shape when these populations ae compaed (MacLaughlin and Buce, 1986; Patiquin et al., 2005; Washbun, 1948). How genetic and othe intinsic o extinsic factos influence bone shape diffeences could be studied in human osteology in moe detail if hip bone shapes ae distinguished o categoized using a spectum of mophology. The existence of these and othe dynamic popeties of bone gowth and development ae some easons why it is impotant to epesent the shape diffeences of the hip bone as a spectum of mophology within biology.

24 Cetainty when estimating sex fom the hip bone 11 Cetainty in sex estimation is necessay in human osteology in ode to instill confidence in the method of sex estimation used, and because identification of skeletal mateial in foensic cases equie that the esults stand up to coss-examination scutiny (Byes, 2002; Mays, 2010; Nodbladh and Yates, 1990). Phenice (1969) and Bůžek (2002) use inclusive language to descibe the mophological ovelap between males and females as "intemediate" sex, denoting a place in-between the sexes, athe than the tem "ambiguous" sex used by Buiksta and Ubelake (1994) that depicts an unknown o unclea mophology. The language used by Buiksta and Ubelake is pat of the standad methods of sex estimation and as such, the idea of ambiguity in sex estimation speads. The esponse then is to ceate new methods of sex estimation that attempt to incease cetainty of sex estimation in an attempt to conque the idea of an ambiguous sex (Bůžek, 2002; Roges and Saundes, 1994). Howeve, uncetainty in sex estimation might have less to do with the method used and moe to do with the specific use of teminology aimed at descibing completeness of the bone on which the sex estimation method is being pefomed (Mays, 2010). The tems used in Bown (1998), in ode of most confident to less confident, illustate the eliability of sex estimation on incomplete skeletal emains: "likely," "possible," o "pobable," male o female. The tem "pobable" is also used by Buiksta and Ubelake (1994) to distinguish uncetain sex estimations fom confident sex estimations. When compaed to Bown's teminology, it could be assumed that the level of confidence Buiksta and Ubelake ae efeing to in a "pobable" sex estimation has the same level of confidence as Bown's "pobable" sex estimation. Thee is no way of

25 12 knowing fo sue if the two tems ae efeing to simila levels of confidence. Howeve, the impotant point is to distinguish, eithe by nomenclatue o in text, when uncetain sex estimation is due to incompleteness of the emains o of the taits used, and when uncetainty is due to the accuacy of the method used to estimate sex. When emains ae complete, sex estimation teminology should eflect an inclusive nomenclatue fo the mophological vaiation within the study sample. If the teminology of sex estimation categoies pesented less ambiguous language and use a nomenclatue that emphasizes mophological vaiation, confidence in sex estimation could incease How to Categoize sex What is sex? The idea of sex has gone though a seies of incanations. Beginning as a substitute fo "gende" and "sexuality," "sex" was citicized fo being a static, polaizing, and confining tem (Butle, 1993; Gilchist, 1999; Lobe, 1996). Sex and gende wee late defined sepaately, sex was defined as petaining to biology while gende was defined cultually (Gilchist, 1999). Sex, not sepaated fom sexuality, etuned once again to the theoetical ealm of a cultual constuct as the heteosexual hegemonic stuctue of sexuality and gende theoies began to beakdown (Butle, 1993; Gelle, 2005; Gilchist, 1999; Nodbladh and Yates, 1990). If sex is isolated fom ideas of sexuality and gende, and looked upon as the culmination of genes, homones, genitals, and bones, opposing theoies compete to define how sex should be categoized and what the basis of that categoization should be. Soensen (2000) noted that the issue suounding sex lies in how sex is classified and not in its manifestation as a cultual o biological constuct. Classifying sex dichotomously based on autosomal combination in

26 13 the nucleus seems a staightfowad appoach, XX indicates female XY indicates male. Howeve, nuclea DNA is often degaded in ancient skeletal samples, and the small Y allosome is difficult to amplify making this technique uneliable fo skeletal specimens (Bown, 1998; Stone, 2008; Ubelake, 2008). As illustated above, sex based on skeletal mophology is moe complicated than a dichotomous model. Sex detemining factos affecting endocine secetion incites mophological vaiation in the skeleton within male and female goups (Bleche and Eickson, 2007; Fausto-Steling, 2000; Nodbladh and Yates, 1990). Changes in mophology due to evolution and adaptation ceate mophological vaiation between populations and contibute to the mophological ovelap between the sexes when populations ae examined togethe (MacLaughlin and Buce, 1986; Plavcan, 2001; Rosenbeg, 2002; Washbun, 1948). In ode to assess sex in skeletal emains on a global scale it is impotant to develop a univesal system of categoization that bases skeletal sex on mophology using a teminology that includes vaiation in shape expession within males and females. The five-sex categoization scheme, descibed on page 14, accomplishes this. This eseach will contibute to the discussion of sex categoization, specifically in advocacy of a five-scale categoization scheme fo identifying sex by hip bone mophology Sex Estimation Methods Cuently, thee ae seveal ways to estimate the sex of an individual using the hip bone. The methods can be eithe odinal in natue, meaning sex is estimated based on mophological featues and is given a anked value based on its degee of "maleness" o

27 "femaleness," o metic in natue, using absolute measuements to classify sex. The 14 following section will outline the benefits and limitations of each sex estimation technique and conside an altenative appoach that combines the benefits of both odinal and metic methods Odinal methods Odinal methods of sex estimation ae the visual assessment and scoing of sexually dimophic non-metic taits. Skeletal sex is estimated along a continuum of female, possible female, intemediate, possible male, and male, accoding to the expession of non-metic taits. Taits could be given a numbe value, o a scoe, fom which sex is estimated, o the pesence/absence of a tait indicate "femaleness" o "maleness" (Bůžek, 2002; Buiksta and Ubelake, 1994; Gómez-Valdés et al., 2012; Phenice, 1969; Walke, 2005). The most sexually dimophic taits of the adult human hip bone (Figue 1.1) include the vental ac, ischiopubic amus idge, subpubic contou located in the egion of the pubic bone, and the shape of the geate sciatic notch in the infeoposteio egion of the ilium (Buiksta and Ubelake, 1994; Klales et al, 2012; Phenice, 1969; Walke 2005).

28 15 Infeoposteio egion of the ilium Figue 1.1: Most sexually dimophic egions of the human hip bone. [Adapted fom Buiksta and Ubelake, 1994:17] Odinal methods demonstated to be highly accuate fo detemining sex using the hip bone. Phenice (1969) epot a 96% accuacy estimating sex in the pubic bone using the vental ac, the subpubic concavity, and the ischiopubic amus idge togethe. Klales and colleagues (2012) developed a new method of estimating sex using Phenice's pubic bone featues to 95% accuacy. Howeve, when only one non-metic tait is used the accuacy of sex estimation declines. Roges and Saundes (1994) tested 17 sexually dimophic taits in the hip bone and found that, when used alone, the vental ac was accuate to 87%, the subpubic contou was accuate to 84%, and the ischiopubic amus was accuate to 80%. A simila level of accuacy was seen in the geate sciatic notch, which was also tested in isolation, by Walke (2005) although Roges and Saundes (1994) documented a highe accuacy (86%) fo this egion using the standad methods outlined by Buiksta and Ubelake (1994). When non-metic taits of the entie pubic

29 16 bone and the geate sciatic notch ae used togethe, sex estimation accuacy is impoved to 98% (Bůžek, 2002; Buiksta and Ubelake, 1994). High accuacy is a stong benefit of these odinal methods, howeve, a dawback to the odinal method is that accuacy is dependent on the completeness of the hip bone, and the expeience o the eliability of the obseve (Buiksta and Ubelake, 1994; Bůžek, 2002; Ðuić et al., 2005; Milne, 1990; Roges and Saundes, 1994). Sex estimation accuacy has been tested between expeienced and inexpeienced obseves in a collection of Baltic skeletons (Ðuić et al., 2005). Diffeences in accuacy between obseves (inteobseve accuacy) was less than 10% when estimating sex in the hip bone, and not supisingly, the moe expeienced obseves estimated sex moe accuately than inexpeienced obseves (Ðuić et al., 2005). Intaobseve accuacy, the same obseve intepeting a single tait multiple times, was as high as 11% fo some taits, such as the ischiopubic amus idge, but as low as 0% fo othe taits, such as the vental ac, indicating that some non-metic taits ae easie to intepet than othes (Roges and Saundes, 1994). In the geate sciatic notch, intaobseve eo was highest when attibuting scoes 3 and 4 and lowest when attibuting a scoe of 1 (Walke, 2005). Accuate visual assessment of non-metic taits on the pubic bone and geate sciatic notch equies knowledge of anatomic positions, oientation teminology, and exposue to a ange of hip bone mophological vaiation to distinguish sex diffeences fom age elated bone changes, tauma, disease, and taphonomic changes (White, 2000). Klales and colleagues (2012) have poduced a vey useful technique detailing the mophological vaiation of the vental ac, the subpubic contou and ischiopubic amus idge, that might help standadize how sex tait mophological vaiations ae intepeted and categoized in

30 17 the futue. Walke (2005) has also ecommended standadized handling pocedues to impove intepetation of the geate sciatic notch mophology, howeve sex estimation was moe accuate without it (Roges and Saundes, 1994). Although these methods attempt to impove the subjective bias of non-metic tait intepetation, it does not eplace the benefits that come out of expeience and exposue to the mophological vaiability of osteological collections Metic methods of sex estimation Metic methods ae useful tools fo estimating sex within hip bone assemblages of high mophological vaiability, because the techniques ae epoducible on most complete hip bones and do not equie one to identify anomalous featues (Bůžek, 2002; Luo, 1995). Thee ae many diffeent ways to quantify sex diffeences including individual measuements, the ischiopubic index, and multivaiate analysis (Bůžek, 2002; Luo, 1995; Patiquin et al., 2005, Walke 2005; Washbun, 1948). The geatest stength to using a metic method is objectivity and epeatability (Bůžek, 2002; Luo; 1995). The ability to obtain simila esults as anothe eseache consistently ae the means to impove intaobseve eo though measuement at fixed locations, and ae paamount in human osteology when conducting foensic skeletal identifications that will be scutinized in cout (Bůžek, 2002; Byes, 2002). Fo example, Albanese calculated a lowe mean intaobseve eo fo the supeio pubis amus length (0.6%), compaed with 2.7% intaobseve eo fom what he calls "taditional pubic length measuements" (2003:4). Anothe stength of the metic method is the capacity to estimate sex in fagmented skeletal mateial. As with odinal methods, fagmentay emains limit the

31 numbe of highly dimophic hip bone landmaks, and as a esult, sex estimation using 18 metic appoaches ae not as accuate elative to complete hip bones. Still, metic methods on fagmented hip bones can be useful when the majo dimophic egions of the hip bone, such as the pubic bone and geate sciatic notch, ae not pesent (Aun et al., 2012; Patiquin et al., 2005). Although it appeas that metic techniques would be supeio methods of sex estimation to odinal methods because metic esults ae moe objective, these methods ae not without thei own set of limitations. Thee ae many diffeent ways of measuing intact and fagmented hip bones, theefoe metic methods of sex estimation ae not always compaable between studies (Aun et al., 2012). Fo example, Albanese (2003) applied a evised method of measuing the supeio pubis amus length, which impoved the method by deceasing the intaobseve measuement eo. Similaly, Washbun (1948) and Patiquin and colleagues (2005) both used the ischiopubic index, but they used diffeent landmaks at the acetabulum to obtain thei measuements. In addition, population and tempoal vaiability influence hip bone size and shape, in esponse human osteologists have ceated, o suggested the ceation of population and tempoally specific metic methods (Biwasaka et al., 2012; Luo, 1995; MacLaughlin and Buce, 1986; Patiquin et al., 2005; Rosenbeg, 2002; Washbun, 1948; Zeng et al, 2012). These specific methods of sex estimation ae often not appopiate fo identifying sex of unknown specimens, and tempoally specific metic method of sex estimation might not be applicable to the same population if it expeienced envionmental o cultual changes ove time that influenced hip bone mophology.

32 19 Anothe limitation of metic analyses of sex is that the esults of metic analyses of sex estimation ae only accuate to aound 85%, which is not as high as the accuacies fo odinal methods (Albanese, 2003; Biwasaka et al., 2012; Bůžek, 2002; Milne, 1990; Tague, 2005; Walke, 2005; Washbun, 1948). Metic analyses of sex do not disciminate between male and female hip bone size and shape as well as odinal methods because consideations fo indeteminate sex shape ae seldom made. Consequently, male/female mophological ovelap egistes as eo. One eason fo this consequence is the attempt to identify sex dichotomously athe than incopoating inta-sex vaiation into the calculation. As a esult, the accuacy of estimated sex, although high in metic analyses, is typically less accuate than odinal methods of sex estimation Sex Estimation Using Geometic Mophometics Geometic mophometics (GM) is the study of object fom (size and shape) using a Catesian coodinate system in tangent space, which is conceptualized as a gid system in eithe two o thee dimensions (Bookstein, 1991). Landmaks and semi-landmaks epesent the shape of the object, o the aea of inteest, and ae positioned on points of biological impotance on the object that ae easy to locate and ae pesent on evey specimen (Richtsmeie et al., 2002; Slice, 2005; Zelditch et al., 2012). The landmak coodinates ae ecoded in the tangent space, which can then be subjected to multivaiate compaative analyses to answe questions about the biological significance of cetain shape diffeences. This technique incopoates the benefits of both odinal and metic techniques of sex estimation by captuing size and shape of the hip bone at epoducible

33 points, which is impotant when appoaching new ways to investigate how sex is 20 epesented in the human pelvis. Geometic mophometics compaes the shape and size of skeletal elements in ode to assess diffeences between species, sexes, and populations (Adams et al., 2004; Anastasiou and Chambelain, 2013; Baab et al., 2012; Betti at al., 2013; Bune, 2004; Bytheway and Ross, 2010; Fanklin et al., 2010; González et al., 2009; Schutz et al., 2009; Slice, 2007). This analysis in humans has pedominately focused on canium mophology (Baab et al., 2012; Bigoni et al., 2010; Bune, 2004; Fanklin et al., 2010; González et al., 2011; Kimmele et al., 2008; Manzi et al., 2000; Rosas and Basti, 2002; Sholts et al, 2011; Stand Viðasdótti et al., 2002). Although seveal studies have involved the hip bone (Anastasiou and Chambelain, 2013; Bytheway and Ross, 2010; González et al., 2009; Lycett and von Camon-Taubadel, 2013; Wilson et al., 2011). Geometic mophometics has been vey successful in detemining shape diffeences elated to sex in the whole hip bone complex, the ischiopubic complex, the geate sciatic notch, and the auicula suface, with accuacies in the 88-95% ange (Bilfeld et al., 2012; Anastasiou and Chambelain, 2013; Bytheway and Ross, 2010; González et al., 2009). Because GM has been successful at captuing and measuing sex-based shape of the human hip bone, it can be used to investigate the elationships between whole and patial hip bone shape, sex-based shape, and non-metic taits. The landmak points used to gathe GM shape data ae stategically positioned to captue shape sex-based shape vaiation and ae epoduced exactly on all specimens. The points egiste thee-dimensional coodinates in tangent space: a pojection of theedimensional Euclidean distances (distance between points) on a two dimensional suface

34 21 that esembles the distotion of a globe pojected as a map (Baab et al., 2012). Positional diffeences between the same landmak points of diffeent specimens in this tangent space povide the infomation fo measuing shape diffeences. Once the landmaks ae selected and the shape configuations have been made they ae adjusted using Pocustes supeimposition (see section ) to ensue all specimens ae compaable in size and oientation (Bookstein, 1991; Slice, 2007). A size component, centoid size (the squae oot of the sum of squaed coodinate diffeences fom thei centoid) is emoved to enable components of shape to be analysed (Bookstein, 1991; Zelditch et al., 2012). Howeve, in some cases allometic size diffeences emain between landmak configuations even afte the objects have been scaled to the unit centoid size (Slice, 2007; Zelditch et al., 2012). The stength of using GM in analyses of sex estimation is in its similaity with both metic and odinal methods. Like metic methods, shape diffeences can be quantified and statistically validated, and, like odinal methods, aeas of mophological significance can be compaed in detail (Bilfeld et al., 2012; Bytheway and Ross, 2010; González et al., 2009; Mitteoecke and Gunz, 2009; Richtsmeie et al., 2002; Slice, 2007; Steyn et al., 2004). The benefit of combining the stengths of metic and odinal methods is the multivaiate quantification of non-metic sex tait mophologies that contibute the most to oveall sex-based shape diffeences. Fo example, the subpubic contou and geate sciatic notch can be quantified though Pocustes coodinates that maintains the shape of the contou and notch in the evaluation of sex-based shape diffeences in the human hip bone. Fo the geate sciatic notch, the accuacy of sex

35 estimation impoved 10% using GM elative to both metic and odinal methods, 22 (Bůžek, 2002; González et al., 2009; Walke, 2005). Quantifying shape though GM is also beneficial when applying the investigation of sexual dimophism to patial human emains. Odinal and metic esults identifying sex fom patial hip bones have eached accuacies between 80-90% (Aun et al., 2012; Bůžek, 2002; Patiquin et al., 2005; Roges and Saundes 1994). Sexually dimophic shapes have been deived fom patial human hip bone shapes using GM to an accuacy of just unde 95% (Anastasiou and Chambelain, 2013; González et al., 2009; Wilson et al., 2011). The supeio accuacy of GM in the analysis of sexual dimophism in patial hip bone suggests that the use of GM could contibute to accuate sex identification of patial human emains that ae missing some o all of the standad non-metic taits used to estimate sex of unknown skeletal mateial. Consideing the successes GM has achieved in detemining sex-based shape diffeences in the human hip bone, it would be inteesting to investigate the elationship hip bone shape has with non-metic taits and with sex. Based on my pevious agument fo how to categoize sex and how teminology could denote confidence, this study will estimate sex using standad odinal methods and classified as eithe male, possible male, indeteminate, possible female, and female. The pupose of this investigation would be to detemine the elationship non-metic taits have with whole and patial hip bone shapes and to detemine whethe odinal categoies of sex ae discenible using GM epesentation of whole and patial hip bone shapes.

36 1.4. Significance of Study 23 A deepe undestanding of how whole and patial hip bone shape influence the expession of non-metic taits will be ganeed by this study. It will also contibute to a deepe undestanding of the elationship between hip bone shape and sex categoization by identifying the non-metic taits that contibute the most to the sex-based shape and sex categoization. If GM is successful at discening the shape diffeences between the hip bones classified as male, possible male, indeteminate sex, possible female, and female in this study, it could contibute valuable knowledge to ou undestanding of how sex is expessed mophologically in the hip bone. This study will also contibute to the discussion of how to ecod and categoize sex in human osteology and biological anthopology: is a dichotomous method of sex categoization sufficient, o is a boade categoization scheme, such as the one used in odinal methods, moe appopiate fo captuing mophological vaiation both within sex goups and between populations. This study could lead human osteologists to discen futue steps to a moe accuate (ove 98%) sex categoization, and to moe confident categoy labels that would convey sex identification within vaying hip bone mophologies.

37 24 Chapte 2 : Mateials and Methods Thee ae two questions diving this eseach. Fist, what ae the hip bone shape diffeences, obtained using geometic mophometics (GM) that contibute to the categoization of sex as female, possible female, intemediate, possible male, o male? Second, what elationships exist between sex-based shape diffeences of the hip bone and the odinal taits used to estimate sex? The assumption inheent in these eseach questions is that the landmaks selected fo GM analysis adequately epesent the sex diffeences in hip bone shape Mateials The samples used to answe the eseach questions consisted of 59 left hip bones obtained fom osteological teaching specimens housed by the Life Sciences Depatment at the Univesity of Bitish Columbia (UBC). These specimens ae undocumented, meaning the identity of each individual (age at death, sex, and ancesty) is unknown. Among the specimens available fo study, only complete left hip bones wee included in the study sample to maximise the potential fo landmak selection on the specimens and to maximise the accuacy potential duing the sex assessment pocess Methods In ode to investigate sexual dimophism in the hip bone and the elationship between components of sex-based shape and the standad non-metic taits used in sex

38 25 estimation, two main types of data wee collected. The fist type is a visual assessment of sexually dimophism fom non-metic taits. The tait scoes wee ecoded and used to assign each specimen to one of five sex categoies: female, possible female, indeteminate sex, possible male, o male. The second type of data is landmak coodinate data that was ecoded fom thee-dimensional suface scans of the individual hip bones and used in geometic mophometic (GM) analysis. The NextEngine desktop 3D lase scanne (NextEngine, Inc) was used to captue the hip bone suface and to ceate a thee-dimensional model of a complete hip bone. Landmak 3.6 softwae (Institute fo Data Analysis and Visualization) was used to place landmaks that epesent hip bone shape onto the thee-dimensional hip bone model and to ecod the landmak coodinates needed fo GM analysis. Geometic mophometic and statistical analyses wee pefomed using MophoJ softwae (Klingenbeg, 2011) and SPSS 17.0 (IBM SPSS Statistics, 2008) Sex estimation Sex estimation on a five-scale scoing system was assessed visually fo each hip bone using standad non-metic taits of the pubic bone and geate sciatic notch (Buiksta and Ubelake, 1994; Klales et al., 2012; Phenice, 1969; Walke, 2005). The non-metic taits of the pubic bone: the vental ac, subpubic contou and ischiopubic amus idge, wee evaluated using the scoing system outlined by Klales et al (2012), summaized in table 2.1, which expands the ange of mophological vaiation consideed by Phenice (1969). Klales and colleagues' method of estimating sex in the pubic bone was used in this study athe than Phenice's (1969) method because the fome makes it

39 26 easie to compae pubic bone mophology with geate sciatic notch mophology that also uses a five-scale scoing system and to compae all non-metic taits with five sex categoies. Table 2.1: Mophological desciption of non-metic tait scoes. [adapted fom Klales et al., (2012) and Buiksta and Ubelake (1994)] Non-metic Tait Vental Ac Subpubic contou Ischiopubic amus idge Geate sciatic notch Scoe 1 Scoe 2 Scoe 3 Scoe 4 Scoe 5 40 degees fom the pubic symphyseal face well developed subpubic concavity shap idge with a naow ascending amus Vey wide angle 25 to 40 degees fom the pubic symphyseal face slight subpubic concavity ounded o flattened idge with a naow amus Modeately wide angle less than 25 degees fom the pubic symphyseal face no subpubic concavity/ convexity naow amus with no idge pesent Medium sized angle paallel to the symphyseal face small subpubic convexity slightly wide amus with no idge pesent Modeately naow angle absence of a vental ac lage subpubic convexity vey wide amus with no idge pesent Vey naow angle The vental ac, is descibed as a slightly elevated idge of bone, which extends fom the pubic cest and acs infeioly acoss the vental suface of the lateal most extension of the subpubic concavity and is also the location of the lateal bode of the sulcus fo the neves of the penis and clitois (Phenice, 1969:298; Šedý et al., 2008). The idge of bone that makes up the neve sulcus is moe medially and infeioly oiented in male hip bones, a distinct mophology fom the moe lateally oiented neve sulcus that is chaacteistically female (Andeson, 1990; Klales et al., 2012; Šedý et al., 2008). Klales and colleagues (2012) chaacteize scoes 1 and 2 as female vental ac shape,

40 27 while scoes 4 and 5 chaacteize male vental ac shape. Scoe 3 incopoates possible vental ac shape fom eithe sex (Figue 2.1). The subpubic contou is the site of attachment fo the gacilis muscle and becomes sexually dimophic because of the diection of gowth of the ischial tubeosities duing adolescent development (Coleman, 1969; Scheue and Black, 2000). Rapid infeio gowth of the ischiopubic amus and lateal gowth of the ischial tubeosities ceates the subpubic concavity in females (Figue 2.1, scoes 1 and 2). In males the aea is moe convex (Figue 2.1, scoes 4 and 5) due to geate infeio gowth of the ischial tubeosities and geate thickness of the ischiopubic amus possibly due to a obust gacilis muscle attachment (Buiksta and Ubelake, 1994; Coleman, 1969; Klales, 2012; Scheue and Black, 2000). In females, the lateal cuve of the ischiopubic amus stats below the infeio magin of the pubic symphysis foming a concavity that is absent in males, howeve, males often display a ponounced convexity of the infeio pubic amus (Klales et al., 2012). When left and ight hip bones ae aticulated at the pubic symphysis the left and ight ischiopubic ami fom the subpubic angle. The degee of the subpubic angle eflects the shape of the pelvic outlet, which is wide in females than in males to accommodate the passage of the fetus duing patuition, leading to a geate subpubic angle. The ischiopubic amus idge is ceated by simila gowth pattens as the subpubic contou. The idge is located on the medial aspect of the ischiopubic amus immediately below the pubic symphysis and foms a naow, cest like idge in females (Figue 2.1, scoes 1 and 2) which is absent in males (Figue 2.1, scoes 4 and 5) (Buiksta and Ubelake, 1994:17).

41 28 Figue 2.1: Five scale scoing system fo the subpubic contou (top), the ischiopubic amus idge (middle) and the vental ac (bottom). Scoes 1 and 2 in each image epesents typical female mophology, scoe 3 epesents indeteminate mophology, scoes 4 and 5 epesent male mophology. [Repoduced fom Klales et al., 2012:4] The geate sciatic notch of each specimen was assessed accoding to the standad obsevation methods outlined by Buiksta and Ubelake (1994) and by Walke (2005). The angle of the geate sciatic notch is defined as the ac that is ceated by following the anteio suface of the dosal aspect of the hip bone beginning at the posteio infeio point of the peauicula sulcus, infeio to the auicula suface, and teminating at the ischial spine (Walke, 2005). The width of the geate sciatic notch is govened by the diection and amount of gowth of the posteio potion of the ilium duing adolescence (Coleman, 1969). Males have a moe polonged supeio gowth of the posteio potion of the ilium ceating a naow notch (Figue 2.2 scoe 3, 4, and 5) wheeas females show

42 29 a polonged lateal gowth ceating a wide notch (Figue 2.2 scoe 1) (Coleman, 1969). Scoe 2 tends to epesent indeteminate sex (Walke, 2005). The shape of the geate sciatic notch in females ceates a geate posteio component of the tue pelvis and the pelvic outlet that contibute to patuition success (Hage, 1996). Figue 2.2: Five scale scoing system fo the geate sciatic notch. Scoe 1 epesents typical female mophology, scoe 2 epesents indeteminate mophology, scoes 3, 4 and 5 epesent male mophology. [Repoduced fom Buiksta and Ubelake, 1994:18] Each specimen was assigned to one of five sex categoies based on the mean scoe of the fou non-metic taits. A specimen with a modal scoe of "1" acoss all fou taits was categoized as female, "2" was categoized as possible female, "3" was consideed indeteminate sex, "4" was categoized as possible male, and "5" was categoized as male. Howeve, in pactice, it was vey ae fo a specimen to expess all of the chaacteistics that ae expected in one sex categoy, the majoity of the specimens expessed non-metic tait mophologies that ae chaacteistic of two o moe sex categoies. The mean scoe in such cases would esult in a decimal that would have to be ounded up o down to a whole numbe epesenting the sex categoy. Because the whole

43 30 numbes ae not anked, that is "5" is not lage than "1" a typical ounding pactice is not appopiate. The decision, whethe to ound up o down, was made to align the sex estimation with the mode scoe. Fo example a specimen with scoes esembling 4;2;2;3 eceived a mean scoe of 2.75 which would typically be ounded up to 3, as the mean is close to that value, but the sex estimation is close to 2, as two taits suggest possible female. In this case, the mean scoe was ounded to 2 to suggest a possible female. In anothe example, a specimen with scoes esembling 3;3;3;2, which also poduced a mean scoe of 2.75, was ounded up to 3 because moe of the non-metic taits suggest an individual of indeteminate sex athe than possible female sex. In instances of bimodal sex estimations, fo example 1;1;2;2 o 4;4;5;5 moe weight was given to the tait scoes that estimated sex moe confidently. In the pevious case, the mean was ounded to fit the confident sex estimation female (1) and male (5) than to the possible female (2) o possible male (4). In instances whee a bimodal scoe included indeteminate sex, such as 2;2;3;3 o 4;4;3;3 moe weight was given to the possible sex categoy ove the indeteminate sex categoy. Fo specimens that did not have a mode scoe to assist in sex categoization, fo example 4;3;2;5, the mean value of 3.5 was ounded up to 4 (possible male) because thee ae moe male like non-metic taits (scoes 4 and 5) than female like non-metic taits (2) NextEngine lase scanne The specimens wee scanned using the NextEngine desktop thee-dimensional suface scanne (NextEngine, Inc.). The scanne uses nomal light and a seies of 4 class 1M lases to captue both the suface colou and suface topogaphy of an object

44 31 (NextEngine, Inc. no date). The geometic point esolution was set to captue 310 points pe cm 2 fo objects in a wide field of view with an accuacy of up to 0.038cm (esolution published as 2.0k points pe squae inch with an accuacy of inch NextEngine, 2009). Each specimen equied epositioning at a pependicula oientation in ode to captue as much pelvic topogaphy as possible. The fist hip bone position secued the long axis of the pelvis paallel to the vetical am of the PatGippe (Figue 2.3A). The ischiopubic amus was oiented in the cente of the PatGippe platfom and the ilium was oiented ove the ischiopubic amus so that the anteio supeio and posteio supeio iliac tubeosities wee within the bodes of the tuntable. The scanne was set to captue the image in 360 degees with eleven scans in this oientation. The second scan position had the long axis of the pelvis lying on the PatGippe platfom pependicula to the scanne base in ode to captue the supeio suface of the iliac cest, infeio suface of the ischiopubic amus, and the inside of the acetabulum that wee missed in the fist scan position. The hip bone was oiented to ensue that the ischiopubic amus and the apex of the ilium would fit inside the tuntable boundaies and that the scanne could captue all of the hip bone (Figue 2.3B). The scanne was set to captue the image in 360 degees with eight scan in this oientation. If these two scans positions did not captue the entie shape of the pelvis, single scans wee taken of the missing aea(s) to fill in the missing data.

45 32 A B Figue 2.3: Image "A" the fist hip bone scan position paallel to the NextEngine PatGippe. Image "B" the second hip bone scan position pependicula to the PatGippe. The multiple scans wee fused into a single thee-dimensional image using ScanStudio softwae (ScanStudio HD 1.2.0, NextEngine, Inc). The fuse settings wee selected fo no hole filling and a Resolution Ratio of 0.9 (default setting) to maintain the same mesh tiangle size as the oiginal scans (NextEngine, 2009). On thee occasions (UBC_50, UBC_51, UBC_53) suface hole filling was equied on the iliac cest and the ischiopubic amus to accommodate landmak placement. The thee holes wee no moe than 5 cm long and 1 cm wide. Because the holes wee on a cuved suface the fill holes settings wee set fo a cuve to follow the natual outline initiated by the boundaies in the oiginal scan data. This function did not affect the integity of the landmak data in these aeas because the hole filling function seved only as a suppot fo the landmak aleady in contact with oiginal suface data. The suface scans wee then expoted as.ply files to be impoted fo landmak placement.

46 Landmak placement Bookstein (1991) descibes thee types of landmaks that ae used in GM and used in this eseach. Type 1 landmaks ae discete juxtapositions, defined in tems of intesecting stuctues such as between sutues o the banching points of a tee. Type II landmaks ae maxima of cuvatue o othe local mophogenetic pocesses (Bookstein, 1991: 64). This categoy includes locations on an object that expeience push o pull foces such as the tips of muscle attachments on bone, o the anges of a cuve such as the cone of the jaw and the cones of the obital im (Bookstein, 1991: 65). Type II landmaks ae defined in tems of local featues, but they ae not suounded on all sides by stuctues as in Type I. In contast, Type III landmaks ae extemal points and ae defined in tems of locations futhest away fa away fom anothe landmak such as end points. "Fuzzy" landmaks of types I and II ae lage than single point landmaks, but ae still ecognized as aeas of biological significance (Bytheway and Ross, 2010). Landmaks should be selected accoding to how easy they ae to locate by inexpeienced uses and how epeatable the landmaks ae on all of the specimens being studied (Bytheway and Ross, 2010; Slice, 2007). Thity landmaks, 9 Fuzzy type I, 13 type II, 8 type III, (Table 2.2, Figue 2.4) wee selected to epesent hip bone shape and sexual dimophism. The twenty-five landmaks that Bytheway and Ross (2010) found to captue the most significant hip bone sexual dimophism wee selected. Bytheway and Ross selected landmaks based on seveal citeia including: demonstated significance in the liteatue, epeatability among the specimens, epesentation of object shape, epesentation of biological impotance in

47 34 the fom of sex diffeences, and egions that have not been used in metic analysis. Five new landmaks wee selected to complete the hip bone shape (Landmak 7, 28, and 30), and to epesent the sexually dimophic qualities identified by Bůžek (2002). Table 2.2: Landmak types and definitions. Landmak Hip Bone Landmak Type Region II Ilium 1. Anteio infeio iliac spine II Ischium 2. Ischial spine II Ilium 3. Iliac tubecle II Ilium 4. Anteio supeio iliac spine II Ilium 5. Posteio supeio iliac spine "Fuzzy" Pubis 6. Midpoint of the pubic symphyseal face II Ilium *7. Posteio infeio point of the peauicula sulcus II Pubis 8. Pubic tubecle II Ilium 9. Point of maximum cuvatue in the geate sciatic notch III Ilium 10. and *11. Two points of the auicula suface that poduce the maximum width at the anteio potion III Ischium 12. and 13. Two points on the ischium that poduce the maximum width of the ischial tubeosity III Pubis 14. The most infeio medial point on the obtuato foamen im III Ischium 15. The most supeio lateal point on the obtuato foamen im II Pubis 16. The most anteio infeio point of the lunate suface III Pubis 17. Most supeio point on the symphyseal face II Ischium 18. The most posteio infeio point of the lunate suface II Pubis 19. Acuate (iliopubic) eminence III Pubis 20. Ischiopubic amus at the naowest point infeio to the pubic symphysis "Fuzzy" Ilium 21. Posteio gluteal line "Fuzzy" Ischium 22. Most posteio point on the ischial tubeosity "Fuzzy" Ischium 23. Most infeio point on the ischial tubeosity "Fuzzy" Pubis 24. Most infeio point on the symphyseal face III Pubis *25. Most lateal point of the phallic idge on the ischiopubic amus "Fuzzy" Ilium 26. Infeio gluteal line "Fuzzy" Ilium 27. Anteio gluteal line "Fuzzy" Ilium *28. Maximum ac of the iliac cest II Ilium 29. Posteio infeio iliac spine "Fuzzy" Ischium *30. Most supeio pat of the ischial tubeosity * Indicate new landmaks ceated fo this eseach

48 A B C D Figue 2.4: Landmak placement and wiefame gaph compaison. A: MophoJ wiefame image Axis 1 vs. 2. B: Landmak opaque image with landmaks; anteio view. C: MophoJ wiefame image Axis 1 vs. 3. D: Landmak opaque image with landmaks; posteio view. Bůžek (2002) identified the composite ach and the phallic idge as two shape featues of the pelvis that contibute to sexual dimophism. The composite ach is compised of the cuvatue of the anteio potion of the auicula suface and cuvatue

49 of the anteio potion of the sciatic notch. In females, both contous make up two 36 distinct cicles with diffeent adii, which fom the composite ach. In males, both contous fom the cicumfeence of one cicle, in which case thee is no composite ach. This site of sexual dimophism was not included as a sex tait to be measued against the geometic mophometic esults because it is a metic method of sex estimation athe than an odinal method. Landmaks 10 and 11 ae positioned on the anteio potion of the auicula suface and ae included in this study to captue the shape diffeences of this aea that Bůžek (2002) alludes to between males and females in his study. The phallic idge is a lateal pojection of bone on the ischiopubic amus infeio to the pubic symphyseal face that is mophologically distinct in males with a boad ischiopubic amus and no idge (Bůžek, 2002). Landmak 25 was selected to captue the ange of shape vaiation in the location of the most lateal point of the phallic idge and detemine the level of sexual dimophism in this anatomic featue. The thee-dimensional models wee impoted into the Landmak 3.6 softwae (Institute fo Data Analysis and Visualization, 2002) as.ply files in ode to apply the landmaks (Figues 2.4B and 2.4D) using a semi-automated pocess. The pocess consisted of selecting a efeence image (UBC_01) and manually placing all of the landmaks on it. The fist ten landmaks wee manually applied to all subsequent specimens befoe the emaining landmaks wee applied automatically on each model by the softwae. The ten manually placed landmaks seve as a coodinate efeence so the softwae can judge whee to place each emaining landmak. Despite the efeence locations, each automatically placed landmak equied manual efinement to ensue it was placed coectly (Landmak Use Guide, 2007). Landmaks configuations wee also

50 ceated to epesent the shape of the ilium, ischium, and pubis independently (as 37 indicated in Table 2.2, Figue 2.5) and the combined ilium-ischium, ilium-pubis, and ischium-pubis datasets that epesent vaious aspects of fagmented hip bones Figue 2.5: Landmaks gouped into hip bone egions, ilium in oange, ischium in blue, and pubis in ed Geometic mophometic and statistical analysis Geometic Mophometic analysis was used in this study to quantify hip bone shape vaiation in whole and patial segments in ode to assess the sexual dimophism of hip bone shape and to detemine the elationship between non-metic tait mophology and hip bone shape in whole and patial segments. The pocess stated by aligning the landmak configuations of the 59 specimens into a common size and oientation though Pocustes supeimposition using tanslation, scaling, and otation. A statistical test of