ippa cambodia talk - lb1 mandible
DESCRIPTION
TRANSCRIPT
3D geometric morphometrics of Microcephalic and Cretin mandibles support the new species diagnosis of
LB1 (Homo floresiensis)
1Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, 2Department of Anatomical Sciences, Stony Brook University Medical Center
Kyle Marian A Viterbo1, William Jungers2
The Hobbit of Flores, Indonesia
Brown et al. 2004; Brown and Maeda 2009; Morwood et al. 2005; map – Voris 2004
The Hobbit of Flores, IndonesiaCompeting Hypotheses
1) Remnant of a pre-H. erectus or early Homo dispersal out of Africa
2) Island-dwarfed Asian Homo erectus
3) Modern human from Asian Pygmy population
4) Small-bodied pathological modern human
Argue et al. 2006; Baab and McNulty 2008; Baab et al. 2007; Bromham and Cardillo 2007; Brown et al. 2004; Hershkovitz and Kornreich 2007; Jacob et al. 2006; Kaifu et al. 2011
Sangiran 17 (left) and LB1 (right).
The Hobbit of Flores, Indonesia
Unusual modern Homo sapiens? Recent dates = recent modern population? Modern dwarfed Australomelanesian Pygmy skeleton (Jacob et al. 2006)
Negative/neutral “chin” also found in Australomelanesian populations Short stature not unusual for Island Southeast Asia
Small-cranium pathology (Microcephaly, Cretinism, Laron Syndrome, etc.)
Do the LB1 and LB6 mandibles fall within the range of anatomically modern human shape variation?
X-ray & profile of a male Rampasasa Pygmy from Flores (Jacob et al. 2006)
Microcephaly Cretinism (Hypothyroidism)
Mandibles in Paleoanthropology
Mandibles represent a large portion of the Human fossil record.
Mandibular morphology• Recognizing new species• Designating taxonomy to
fossil finds
Ardipithecus ramidus
Australopithecus anamensis
Praeanthropus afarensis
A. bahrelghazali
Homo antecessor
Bermúdez de Castro et al. 1997; Kaifu et al. 2005a; Kaifu et al. 2005b; Lague et al. 2008; Nicholson and Harvati 2006; Rosas and Bermúdez de Castro 1998
The Liang Bua Mandibles
DIAGNOSTIC FEATURES① Coronoid process higher
than mandibular condyle
② Posteriorly-oriented ascending ramus
③ No chin
④ Posteriorly-inclined symphyseal axis and alveolar planum
⑤ Presence of an inferior and superior transverse tori
• LB1 and LB6 exhibit the same morphology
• Combines features from Plio-Pleistocene hominins
• Unlike Zhoukoudian and Sangiran H. erectus
Brown et al. 2004; Brown and Maeda 2009
The Liang Bua Mandibles
BROWN & MAEDA (2009)
Compared to Homo sapiens Homo erectus Australopithecus afarensis
Results H. floresiensis outside human
range of variation Shares aspects of symphyseal
and corpus shape, and robusticity with A. afarensis
Molar size, facial height, and corpus shape diverge from australopithecine pattern
a. Homo sapiens from Upper Cave Zhoukoudian, China; b. a microcephalic H. sapiens from Mauritius (Peabody Museum, Harvard Univ.); c. Homo floresiensis (LB1); d. H. floresiensis (LB6); e. early African Homo erectus (KNM-WT 15000); f, Australopithecus afarensis (Laetoli Hominid 4)
MethodsData acquisition• Microscribe G2X digitizer• Landmark.exe
Shape and statistical analysis• Semi-landmarks resampled with
Resample.exe (NYCEP)• Generalized Procrustes Alignment
(GPA)• Principal Components Analysis (PCA) • MANOVA and Canonical Discriminant
Analysis (CDA) • LB1 treated as an unknown
Analysis A: whole mandible78 homologous landmarks
Analysis B: superior ramus omitted66 homologous landmarks
Materials• 250 Non-pathological modern
humans • Adult• Sub-adult• Fossil Homo sapiens• African & Asian Pygmies
• 11 Microcephalic*• Musee de l’Homme• Basel Natural History Museum• Royal College of Surgeons,
Edinburgh
• 18 Cretin (Hypothyroidism)*• Basel Natural History Museum• Royal College of Surgeons,
Edinburgh
• LB1
• Analysis A: 9 Fossil casts and reconstructions
• Analysis B : 18 fossil hominin casts/reconstructions**• Teshik Tash (subadult H. neanderthalensis)
• Pech De l’Aze (subadult H. neanderthalensis)
• Gibraltar 1 (H. neanderthalensis)
• Mauer (H. heidelbergensis)
• La Quina 5 (H. neanderthalensis)
• Lantian 1 (H. erectus)
• Tighenif 3 (H. erectus)
• Amud 1 (H. neanderthalensis)
• Sima de los Huesos 5 (H. heidelbergensis)
• Ehringsdorf Cave (H. sp.)
• Peninj 1 (P. boisei)
• D2735 (Dmanisi H. erectus/ergaster/georgicus)
• DNH7 (Drimolen P. robustus)
• Atlanthropus (H. erectus)
• KNM-WT 15000 (H. erectus/ergaster)
• SK 15 (H. sp.)
• AL 288-1 (A. afarensis)
• MK4 (A. africanus)*Specimens directly correspond with material from Obendorf et al. 2008, Oxnard et al. 2010, Oxnard et al. 2012
RESULTS (A): Principal Components Analysis
PC 1 (20.32%) PC 2 (11.49%) PC 3 (10.79%)
RESULTS (A): Canonical Discrimant Analysis
RESULTS (A): Canonical Discrimant Analysis
CLASSIFICATION RESULTSPredicted Group Membership
Original (%)
Grouping 1 2 3 4Non-Pathological (1) 99.2 0.4 0.4 0.0Microcephalic (2) 18.2 63.6 18.2 0.0Cretin (3) 16.7 5.6 77.8 0.0Fossil Hominin (4) 22.2 0.0 11.1 66.7LB1 (unknown) 0.0 0.0 0.0 100.0
Predicted Group Membership
Cross- validated (%)
Grouping 1 2 3 4Non-Pathological (1) 98.8 0.8 0.4 0.0Microcephalic (2) 45.5 27.3 27.3 0.0Cretin (3) 16.7 27.8 55.6 0.0Fossil Hominin (4) 22.2 0.0 11.1 66.7
RESULTS (B): Principal Components Analysis
PC1 (21.45%) Wireframes
PC2 (13.88%) Wireframes
PC3 (10.46%) Wireframes
RESULTS (B): Canonical Discrimant Analysis
RESULTS (B): Canonical Discrimant Analysis
RESULTS (B): Canonical Discrimant Analysis
Specimen Actual Group
Highest Group Second Highest Group
Predicted Probability Mahalanobis D2 Predicted Probability Mahalanobis D2 MNHN 25298 2 1 81.0% 4.350 2 17.0% 0.521 MNHN 25301* 2 1 74.5% 7.757 2 21.6% 3.280 MNHN 29406 2 1 83.0% 4.969 3 12.0% 1.252 MNHN 30212 2 1 90.0% 5.202 2 9.0% 2.788 MNHN sn 2 1 92.0% 3.557 3 6.0% 1.520 NMB cast 2 1 85.0% 5.014 2 14.0% 1.656 NMB G64 3 1 50.0% 11.265 3 48.7% 3.804 NMB G66 3 1 83.0% 3.608 2 13.5% 0.284 NMB G68 3 1 97.0% 1.017 2 2.0% 1.894 NMB 578 3 2 53.0% 1.195 3 28.0% 1.864 Teshik Tash* (H. neanderthalensis) 4 1 72.4% 9.923 3 23.5% 4.640 Pech de l'Aze* (H. neanderthalensis) 4 3 62.0% 10.271 1 37.0% 18.850 Amud 1 (H. neanderthalensis) 4 1 99.7% 6.772 4 0.3% 13.464 Dmanisi D2735* (H. erectus) 4 1 50.0% 8.381 4 50.0% 3.285 LB1 (unknown) ungrouped 4 98.8% 3.732 1 1.2% 17.718
CLASSIFICATION RESULTSPredicted Group Membership
Original (%)
Grouping 1 2 3 4Non-Pathological (1) 99.6 0.0 0.0 0.4Microcephalic (2) 75.0 25.0 0.0 0.0Cretin (3) 0.05 16.7 77.8 0.0Fossil Hominin (4) 15.0 0.0 5.0 80.0LB1 (unknown) 0.0 0.0 0.0 100.0
Predicted Group Membership
Cross- validated (%)
Grouping 1 2 3 4Non-Pathological (1) 99.2 0.0 0.4 0.4Microcephalic (2) 87.5 0.0 12.5 0.0Cretin (3) 0.05 22.2 66.7 0.0Fossil Hominin (4) 20.0 0.0 5.0 75.0
RESULTS (B): Canonical Discrimant Analysis
RESULTS (B): Canonical Discrimant Analysis
RESULTS (B): Canonical Discrimant Analysis
RESULTS (B): Canonical Discrimant Analysis
RESULTS (B): CV1 shape change (64.77%)
Summary
Principal Components Analysis• LB1’s mandible morphology clusters with
fossils• Microcephalic and Cretin mandibles within
range of non-pathological variation (including adults and subadults)
• Chin, gonion, alveolus height, symphyseal morphology distinguish fossils from modern human group
Canonical Discriminant Analysis• LB1 classified as 98.8% fossil hominin• Microcephalics and Cretins overlap most
with subadult morphology• LB1 is most similar to early fossil Homo,
however more samples needed to verify
Conclusions• LB1 is NOT a microcephalic or a cretin
• Anatomically modern human mandibles with growth-deficiency pathologies do not develop fossil hominin morphology
• Some, though not all, retain subadult morphology• Microcephalic and cretin (Hypothyroidism) mandibles extend
modern human shape space away from fossil hominins from the Middle Pleistocene and older
• Mandible morphology of LB1 and LB6 fall outside the range of normal and pathological modern human variation
• The results support the new species designation, Homo floresiensis, for the Liang Bua material
Acknowledgements• American Museum of Natural History, New York
• Ian Tattersall• Gisselle Garcia
• Musee de l’Homme, Paris• Philippe Mennecier• Veronique Laborde• Aurelie Fort
• Naturalhistoriche Museum, Basel• Gerhard Hotz
• Dept. of Anthropology, University of Geneva
• Royal Belgian Institute of Sciences, Brussels• Patrick Semal
• Royal College of Surgeons, Edinburgh• Andrew Connell
• National Science Foundation Graduate Research Fellowship
• Australian Research Council
• Thomas Sutikna, E Wahyu Saptomo, Michael Morwood
ARKENAS