The Postcranial Functional Anatomy of the Endemic Rats from Liang Bua, Flores, Indonesia E.G. Veatch 1,2,3 , M.W. Tocheri 1,2 , Rokus Due Awe 3 , E. Wahyu Saptomo 3 , T. Sutikna 3 , Jatmiko 3 , Sri Wasisto 3 , K.J. McGrath 1,4 , H.J.M. Meijer 5 , K.M. Helgen 4 1 Department of Anthropology, GWU; 2 Human Origins Program, NMNH Smithsonian Institution, 3 National Research Center for Archaeology, Indonesia, 4 Division of Mammals, NMNH Smithsonian Institution, 5 Institut Catalá de Paleontologia RESULTS Introduction BACKGROUND National Museum of Natural History • Liang Bua, an Indonesian site on the island of Flores, is best known as the type locality of the endemic hominin, Homo floresiensis. Excavations at Liang Bua have recovered an overwhelming amount of vertebrate remains, including more than 200,000 fragments identified to the Muridae family (i.e., rats). • Previous research by Guy Musser (1981) suggests the presence of at least six genera represented on the island (Papagomys, Spelaeomys, Hooijeromys, Komodomys, Paulamys, and Rattus) indicative of small, medium, large, huge and giant body sizes • Current and previous excavations at Liang Bua indicate the presence of at least six rat species through dental remains. • Variation in dental and cranial morphology between Papagomys and Spelaeomys suggests ecological differences among taxa of similar body sizes • Behavior and habitat is essentially unknown for all of these extinct, native taxa, and even some that are still living on Flores (e.g., Papagomys armandvillei) • Here, for the first time we analyze the functional anatomy of recovered calcanei (n=372) and humeri (n=1474) to interpret body size variation, identify species, and behavior. • The femur, humerus and calcaneus show a similar size pattern • There is a high concentration of larger and smaller Komodomys below 3 m depth • Taxa representation appears to change dramatically with the onset of the Holocene MEASUREMENTS HUMERUS Maximum Length* ML Head Diameter AP Head Diameter ML Midshaft Diameter AP Midshaft Diameter Length of Medial Condyle ML Distal Width AP Distal Depth* AP Capitulum Thickness Anterior Articular Breadth* Posterior Articular Breadth** Minimum Articular Thickness CALCANEUS Maximum Length** Maximum Breadth Heel Length* Shelf Length* Midpoint-to-Heel Length Midpoint-to-Cuboid Length Mid Heel Breadth Mid Heel Height Posterior Heel Breadth Posterior Heel Height • The postcranial functional anatomy of the murid calcaneus and humerus suggests a variety of murid species have occupied the available ecological habitats/niches surrounding Liang Bua throughout the late Pleistocene and Holocene • The calcanei and humeri were assigned to a total of seven endemic murid species (Papagomys armandvillei, Papagomys theodorverhoeveni, Spelaeomys florensis, “Hooijeromys”, Komodomys sp., Rattus hainaldi, and Rattus exulans) based on comparisons of size and morphology • Within the medium-sized clusters, there appears to be two groups suggesting the likelihood of a smaller and larger taxon within the genus Komodomys • P. armandvillei, P. theodorverhoeveni, and “Hooijeromys” postcranial morphology suggests these taxa are more adapted for terrestrial behaviors • Spelaeomys calcanei and humeri suggests adaptation for either more (1) arboreal or (2) riverside behaviors • Both elements suggest the presence of a medium to large-sized murid that has yet to be positively identified by dental remains. This “unknown” group appears more functionally similar to Spelaeomys and may represent a terrestrial shrew rat referred to by Musser et al. (1986), which was likely specialized for eating a diet comprised mainly of earthworms A: P. armandvillei was positively identified through comparisons with known specimens (e.g., MCZ) included in analyses B: P. theodorverhoeveni was identified as being a slightly smaller version of P. armandvillei with similar morphology overall C: Spelaeomys was identified based on large size but different morphology than P. armandvillei (e.g., shorter heel, thinner midshaft) D: “Hooijeromys” was identified based on similarities with both species of Papagomys, but smaller in size E: “Unknown” is a group of medium to large-sized calcanei and humeri that exhibit morphology more similar to Spelaeomys but smaller in size PC 2 (3%) PC 2 (3%) Table 1. Liang Bua Murids Species Size class Weight (g) Known Habitat Papagomys armandvillei Giant ~1,200 Modern & Fossil Forest (Terrestrial) Papagomys theodorverhoeveni Huge unknown Fossil Forest (Terrestrial)? Spelaeomys florensis Huge unknown Fossil Arboreal? Hooijeromys nusateggara Large unknown Fossil Grasslands? Paulamys naso Medium ~120 Modern Terrestrial Komodomys rintjanus Medium ~142 Modern & Fossil Grasslands Rattus exulans / Rattus hainaldi Small ~70 Modern & Fossil Various CALCANEUS HUMERUS 1. 1. 2. 2. 3. 3. 4. 4. PC 1 (94%) PC 1 (94%) STRATIGRAPHY Humerus Calcaneus M3 M2 M1 Thomas Sutikna holding a modern P. armandvillei Photo credit: Liang Bua Team Anterior dentition and lower face of P. armandvillei Photo credit: Liang Bua Team Skulls of P. armandvillei (left) and S. florensis (middle and right) Photo credit: Liang Bua Team DISCUSSION Depth (m) Acknowledgements Funding for this research was provided by the Smithsonian Scholarly Studies Program and the Peter Buck Fund for Human Origins Research. Shelf Length Small (R. exulans) Giant (P. armandvillei) Matt Tocheri and Vens measure P. armandvillei Photo credit: Liang Bua Team Maximum Length ML Midshaft Diameter Posterior Articular Breadth Shelf Length Maximum Length ML Midshaft Diameter Posterior Articular Breadth PC 2 (3%) PC 2 (3%) PC 1 (94%) PC 1 (94%) Small Medium Large Huge Giant Small Medium Large Huge Giant 0 5 References Small Medium Large Huge Giant Small Medium Large Huge Giant Small Medium Large Huge Giant • Musser, G.G., 1981. The giant rat of Flores and its relatives east of Borneo and Bali. Bulletin of the American Museum of Natural History, 169(2): 67-176. • Musser, G.G., Van de Weerd, A., Strasser, E., 1986. Paulamys, a replacement name for Floresomys Musser, 1981 (Muridae), and new material of that taxon from Flores, Indonesia. American Museum of Natural History, number 2850:1-10. Depth (m) 0 5 Depth (m) 0 5 Depth (m) 0 5 CALCANEUS HUMERUS Small Medium Large Huge Giant Femur Humerus Calcaneus N = 977 N = 1,116 N = 329 Komodomys Paulamys Spelaeomys Rattus sp. P. theordorverhoeni P. armandvillei Rattus sp. Hooijeromys
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The Postcranial Functional Anatomy of the Endemic Rats from Liang Bua, Flores, Indonesia
E.G. Veatch1,2,3, M.W. Tocheri1,2, Rokus Due Awe3, E. Wahyu Saptomo3, T. Sutikna3, Jatmiko3, Sri Wasisto3, K.J. McGrath1,4, H.J.M. Meijer5, K.M. Helgen4
1Department of Anthropology, GWU; 2Human Origins Program, NMNH Smithsonian Institution, 3 National Research Center for Archaeology, Indonesia, 4Division of Mammals, NMNH Smithsonian Institution, 5 Institut Catalá de Paleontologia
RESULTS
Introduction BACKGROUND
National Museum of Natural History
• Liang Bua, an Indonesian site on the island of Flores, is best known as the type locality of the endemic hominin, Homo floresiensis. Excavations at Liang Bua have recovered an overwhelming amount of vertebrate remains, including more than 200,000 fragments identified to the Muridae family (i.e., rats).
• Previous research by Guy Musser (1981) suggests the presence of at least six genera represented on the island (Papagomys, Spelaeomys, Hooijeromys, Komodomys, Paulamys, and Rattus) indicative of small, medium, large, huge and giant body sizes
• Current and previous excavations at Liang Bua indicate the presence of at least six rat species through dental remains.
• Variation in dental and cranial morphology between Papagomys and Spelaeomys suggests ecological differences among taxa of similar body sizes
• Behavior and habitat is essentially unknown for all of these extinct, native taxa, and even some that are still living on Flores (e.g., Papagomys armandvillei)
• Here, for the first time we analyze the functional anatomy of recovered calcanei (n=372) and humeri (n=1474) to interpret body size variation, identify species, and behavior.
• The femur, humerus and calcaneus show a similar size pattern
• There is a high concentration of larger and smaller Komodomys below 3 m depth
• Taxa representation appears to change dramatically with the onset of the Holocene
MEASUREMENTS
HUMERUS Maximum Length* ML Head Diameter AP Head Diameter ML Midshaft Diameter AP Midshaft Diameter Length of Medial Condyle
ML Distal Width AP Distal Depth* AP Capitulum Thickness Anterior Articular Breadth* Posterior Articular Breadth** Minimum Articular Thickness
CALCANEUS Maximum Length** Maximum Breadth Heel Length* Shelf Length* Midpoint-to-Heel Length
Midpoint-to-Cuboid Length Mid Heel Breadth Mid Heel Height Posterior Heel Breadth Posterior Heel Height
• The postcranial functional anatomy of the murid calcaneus and humerus suggests a variety of murid species have occupied the available ecological habitats/niches surrounding Liang Bua throughout the late Pleistocene and Holocene
• The calcanei and humeri were assigned to a total of seven endemic murid species (Papagomys armandvillei, Papagomys theodorverhoeveni, Spelaeomys florensis, “Hooijeromys”, Komodomys sp., Rattus hainaldi, and Rattus exulans) based on comparisons of size and morphology
• Within the medium-sized clusters, there appears to be two groups suggesting the likelihood of a smaller and larger taxon within the genus Komodomys
• P. armandvillei, P. theodorverhoeveni, and “Hooijeromys” postcranial morphology suggests these taxa are more adapted for terrestrial behaviors
• Spelaeomys calcanei and humeri suggests adaptation for either more (1) arboreal or (2) riverside behaviors
• Both elements suggest the presence of a medium to large-sized murid that has yet to be positively identified by dental remains. This “unknown” group appears more functionally similar to Spelaeomys and may represent a terrestrial shrew rat referred to by Musser et al. (1986), which was likely specialized for eating a diet comprised mainly of earthworms
A: P. armandvillei was positively identified through comparisons with known specimens (e.g., MCZ) included in analyses
B: P. theodorverhoeveni was identified as being a slightly smaller version of P. armandvillei with similar morphology overall
C: Spelaeomys was identified based on large size but different morphology than P. armandvillei (e.g., shorter heel, thinner midshaft)
D: “Hooijeromys” was identified based on similarities with both species of Papagomys, but smaller in size
E: “Unknown” is a group of medium to large-sized calcanei and humeri that exhibit morphology more similar to Spelaeomys but smaller in size
PC
2 (
3%
)
PC
2 (
3%
)
Maximum Length
Table 1. Liang Bua Murids
Species Size class Weight (g) Known Habitat
Papagomys armandvillei Giant ~1,200 Modern & Fossil Forest (Terrestrial)
Papagomys theodorverhoeveni Huge unknown Fossil Forest (Terrestrial)?
Spelaeomys florensis Huge unknown Fossil Arboreal?
Hooijeromys nusateggara Large unknown Fossil Grasslands?
Paulamys naso Medium ~120 Modern Terrestrial
Komodomys rintjanus Medium ~142 Modern & Fossil Grasslands
Rattus exulans / Rattus hainaldi Small ~70 Modern & Fossil Various
CALCANEUS HUMERUS
1. 1.
2. 2.
3. 3.
4. 4.
PC 1 (94%) PC 1 (94%)
STRATIGRAPHY
Humerus
Calcaneus
M3
M2
M1
Thomas Sutikna holding a modern P. armandvillei Photo credit: Liang Bua Team
Anterior dentition and lower face of P. armandvillei Photo credit: Liang Bua Team
Skulls of P. armandvillei (left) and S. florensis (middle and right) Photo credit: Liang Bua Team
DISCUSSION
De
pth
(m
)
Acknowledgements Funding for this research was provided by the Smithsonian Scholarly Studies Program and the Peter Buck Fund
for Human Origins Research.
Shel
f Le
ngt
h
She
lf L
en
gth
Small (R. exulans) Giant (P. armandvillei)
Matt Tocheri and Vens measure P. armandvillei Photo credit: Liang Bua Team
Maximum Length ML Midshaft Diameter P
ost
eri
or
Art
icu
lar
Bre
adth
She
lf L
en
gth
Maximum Length ML Midshaft Diameter Po
ste
rio
r A
rtic
ula
r B
read
th
PC
2 (
3%
)
PC
2 (
3%
)
PC 1 (94%) PC 1 (94%)
Small Medium Large Huge Giant
Small Medium Large Huge Giant
0
5
References
Small Medium Large Huge Giant
Small Medium Large Huge Giant Small Medium Large Huge Giant
• Musser, G.G., 1981. The giant rat of Flores and its relatives east of Borneo and Bali. Bulletin of the American Museum of Natural History, 169(2): 67-176.
• Musser, G.G., Van de Weerd, A., Strasser, E., 1986. Paulamys, a replacement name for Floresomys Musser, 1981 (Muridae), and new material of that taxon from Flores, Indonesia. American Museum of Natural History, number 2850:1-10.
De
pth
(m
)
0
5
De
pth
(m
)
0
5
De
pth
(m
)
0
5
CALCANEUS HUMERUS
Small Medium Large Huge Giant
Femur
Humerus
Calcaneus
N = 977
N = 1,116
N = 329
Komodomys Paulamys Spelaeomys Rattus sp.
P. theordorverhoeni P. armandvillei Rattus sp. Hooijeromys
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