Table Of ContentQUATERNARY MURID RODENTS OF TIMOR
PART I: NEW MATERIAL OF CORYPHOMYS
BUEHLERI SCHAUB, 1937, AND DESCRIPTION OF
A SECOND SPECIES OF THE GENUS
K. P. APLIN
Australian National Wildlife Collection, CSIRO
Division of Sustainable Ecosystems, Canberra
and Division of Vertebrate Zoology
(Mammalogy)
American Museum of Natural History
([email protected])
K. M. HELGEN
Department of Vertebrate Zoology
National Museum of Natural History
Smithsonian Institution, Washington and
Division of Vertebrate Zoology (Mammalogy)
American Museum of Natural History
([email protected])
BULLETINOFTHEAMERICANMUSEUMOFNATURALHISTORY
Number341, 80pp., 21figures, 4tables
IssuedJuly 21,2010
CopyrightEAmericanMuseumofNaturalHistory2010 ISSN0003-0090
CONTENTS
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The environmental context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Systematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Coryphomys Schaub, 1937. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Coryphomys buehleri Schaub, 1937. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Extended description of Coryphomys buehleri. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Coryphomys musseri, sp. nov.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Coryphomys, sp. indet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Species diversity in Coryphomys. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Phylogenetic affinities of Coryphomys. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Paleoecology of Coryphomys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
2
ABSTRACT
LargecollectionsoffragmentaryanimalbonesexcavatedfromarchaeologicalcontextsinEast
Timor between 1968 and 2002 provide new material referable to the recently extinct, gigantic
murinegenusCoryphomys.Wedocumenttheupperandlowerdentitionandpalatalanatomyof
C. buehleri Schaub, 1937, and identify and name a second species of Coryphomys, based on
differencesinmolarsizeandmorphologyandskeletalrobusticity.Alternativeinterpretationsof
the observed morphological and metric variability (sexual dimorphism, resource-based
polymorphism, sample heterochroneity) are each carefully assessed and rejected, and we
conclude that the genus comprised two species of approximately similar body size. Preserved
cranial elements of both species of Coryphomys feature a high degree of anatomical
specialization, including an unusual elaboration of the maxillary sinus complex. Though the
specializedanatomy ofCoryphomysinvites consideration of its phylogenetic relationships,this
exercise is hindered by a demonstrable high level of homoplasy (i.e., multiple, independent
evolutionary losses and gains) in many of the key craniodental features traditionally surveyed
within Murinae, while other features are insufficiently well surveyed for broad-scale analysis.
Nevertheless, our comparisons highlight two potentially related lineages among the
geographically proximate Murinae—the Philippine Phloeomyini and the Australo-Papuan
Hydromyini.TheremainsofCoryphomysarerelativelyscarceinallthearchaeologicalsamples,
but distributional evidence suggests that both species of Coryphomys were found primarily in
upland habitats. Late Pleistocene samplesdocument their former presenceat lowerelevations,
possiblyreflectingcooler climaticconditions atthattime.
INTRODUCTION the majority of which were subsequently
foundelsewherewithintheIndonesianarchi-
Timor is located near the eastern end of pelagoandbeyond(seeGoodwin,1979,fora
the Indonesian archipelago and is the largest summary). Indeed, prior to the 1990s, the
and highest of the Lesser Sunda Islands only potentially endemic Timorese mammals
(fig. 1). The surrounding region is geologi- were twoshrews(Crociduratenuis: treated as
cally young and tectonically active, the a synonym of C. fuliginosa [Blyth, 1835] by
product of late Tertiary collision between Jenkins[1982]butmaintainedbyCorbetand
three major earth units—the Asian and Hill, 1992: 42; and C. macklotti: included
Australiancontinentalplates, andthePacific within C. fuliginosa by Jenkins [1982] but
oceanic plate. Plants and animals of Asian consideredasynonymofC.tenuis byCorbet
and Australian affinities intermingle across and Hill, 1992) and one bat, the enigmatic
theregionanditwasthismeldingoftwosuch Nyctophilus timorensis (see Goodwin, 1979;
different biotas that inspired the nascent Kitchener et al., 1991d, for discussion of this
biogeographer Alfred Russel Wallace, and taxon). The impoverished nature of the
continues to excite the imagination of stu- Timorese mammal fauna was further high-
dents of historical biogeography today. lighted by subsequent discovery through the
Timor was one of the first of the Lesser course of the 1900s of endemic nonvolant
Sunda Islands to be explored biologically, mammals on Seram and several other Mo-
with collections made during the Baudin luccanislands(summarizedbyHelgen, 2003)
expeditions of 1801 and 1803, and subse- and Flores (e.g., Sody, 1941; Kock, 1974).
quently by Mu¨ller, Wallace, and others (see More recent surveys of the Lesser Sunda
Hellmayr, 1914, and Mayr, 1944, for the Islands, particularly by staff of the Museum
history of ornithological collecting). These Zoologicum Bogoriense and the Western
expeditions encountered a distinctive avi- Australian Museum (Kitchener and Mar-
fauna, including a significant number of yanto, 1993, 1995; Kitchener and Suyanto,
endemic species and subspecies. In contrast, 1996; Kitchener et al., 1991a, 1991b, 1991c,
the early expeditions encountered a fairly 1991d, 1994), also resulted in discovery of
impoverishedmammal faunamadeupofthe several additional endemic mammals includ-
familiar suite of domesticates and commen- ing one native rodent extant on Timor,
sals, and a moderate number of bat species, Rattus timorensis (Kitchener et al., 1991a).
3
4 BULLETIN AMERICAN MUSEUM OFNATURALHISTORY NO.341
Fig. 1. Regional map showing the location of Timor and other significant islands and continental
landmassesofWallacea.Thegreyshadingindicatestheapproximateextentoflandthatisexposedwitha
sealeveldepressionof100–120mbelowpresentlevel.NotethatTimorremainsisolatedfromothermajor
islandsand continentallandmassesduring episodesof lowered sealevel.
The first hint of a much higher endemic for detailed study. Mahoney distinguished a
mammalian diversityonTimorcame to light total of four large murids including C.
during excavations by Alfred Bu¨hler (see buehleri, four smaller native murids, and
Sarasin, 1936) in a limestone cave near two commensal murids, the latter found in
Nikiniki in southwest Timor. A damaged association with remains of other introduced
mandible and an incomplete femur of a very mammals including domesticates, and he
large rodent were forwarded to Schaub figured each of the four ‘‘giant’’ rats (Maho-
(1937), who described them as a new fossil ney, appendix 3 in Glover, 1986). Musser
murid, Coryphomys buehleri. The dental (1981b) examined some of this new material
morphology ofC. buehleriwaslater revisited and commented briefly on the possible
by Stehlin and Schaub (1951: 348) who affinities of the Timorese rodents, pending
regarded the morphology of the anterior publication of Mahoney’s full account.
portion of m1 to be unparalleled among Sadly, Mahoney didnotcomplete his studies
murines.Notlong after,additional Timorese of the Timor rats before his death in 1985.
rodent material was recovered by Th. L. Since that time the Glover material has
Verhoeven from archaeological contexts at passed through several sets of hands with
Lian Leluat on the Maubesi River, southern the intention of completing his work, but so
Timor (Verhoeven, 1959). Hooijer (1965) far this goal remains unfulfilled.
described and figured a total of three Additional impetus to document the pre-
dentaries and though he noted considerable historic Timorese rodents arose after recom-
morphological variation, especially in the mencementofarchaeologicalresearchinEast
form of the anterior moiety of m1, he Timor in 2000 by archaeologists from the
concluded that a single species was repre- Australian National University, Canberra.
sented. Excavations in five cave sites, one of them
Large samples of prehistoric mammal studied previously by the Portuguese archae-
remains from Timor first came available ologist Antonio de Almeida, again produced
through archaeological excavations by Ian abundant vertebrate remains from contexts
Glover (1986) over the period 1966–1967. ranging from near contemporary back to
Glover excavated a total of five sites using more than 38,000BP(O’Connoret al.,2002;
systematic methods and retrieved animal O’ConnorandAplin,2007;Vethetal.,2005).
remains from contexts dated back as far as Our studies of the combined Glover and
the terminal Pleistocene. The enormously newly excavated collections inspired a new
abundant and surprisingly diverse rodent interpretation of taxic diversity within this
specimenswereturnedovertoJackMahoney fascinating prehistoric fauna. Like Mahoney
2010 APLINAND HELGEN: NEW MATERIALOFCORYPHOMYS 5
and Musser, we recognize a total of four to over 2000 m. The northern side of the
genera of large to gigantic murine rodents, massifrisesabruptly from thecoast,whereas
and a total of five native smaller murines. in the south and southwest the ranges are
However, we depart from previous assess- fringed by broad alluvial and coastal plains.
ments in distinguishing a higher diversity Rugged relief with steep slopes, often in
among the large-bodied rats, with a mini- excess of 40% inclination, thus typifies much
mum of eight species in the four genera. The of the habitat on Timor, broken locally by
total prehistoric murine fauna of Timor thus valleys, uplifted sedimentary basins and
comprisedatleast13species,somewithclear uneven limestone plateaux.
affinitieswiththemurinefaunaofMelanesia, Timor Island is divided politically in two
others linked to the contemporary murine roughly equal parts—an Indonesian portion
fauna of SoutheastAsia, and othersagain of in the west (forming part of the province of
obscure affinities and potentially more an- Nusa Tenggara Timur) and the independent
cient origin. nationofTimorLorosa’e(EastTimor)inthe
The scale of the descriptive and compara- east.
tiveeffortneededtodocumenttheprehistoric GEOLOGY: Timor is located in the Neo-
Timorese murine fauna requires that it be gene collision zone between the northwest
divided among a number of contributions. continental margin of Australia and the
This first paper sets the scene by describing Banda Island arc system and has a complex
the physical, biological, and archaeological geology that has been subject to contrasting
context of the prehistoric Timorese rodents, tectonic interpretations (Price and Audley-
and presents our conclusions on the taxon- Charles, 1987; Charlton, 1991). A paleogeo-
omy of the genus Coryphomys, with two graphic framework for Eastern Indonesia
species recognized. We also present our based on tectonic and geological evidence is
preliminaryobservationsonthephylogenetic provided by Hall (2002).
relationships and paleoecology of this fasci- Rocks belonging to four major tectono-
nating genus of murine rodent. stratigraphic units are exposed on Timor,
namely: (1) basal, unmetamorphosed sedi-
THE ENVIRONMENTAL CONTEXT mentary rocks of the Australian continental
shelf, ranging in age from Permian to
GEOGRAPHY:Timorisanimpressiveisland Paleocene;(2)metamorphicrocksofvariable
even by global standards, with an area of age, extruded along the subduction zone; (3)
28,418 km2 and a maximum elevation of volcanic fore-arc ophiolites of late Tertiary
2962 m. It is the largest and highest of the age; and (4) Neogene to Quaternary sedi-
Lesser Sunda Islands, and one of the more mentary formations, including postorogenic
varied in terms of climatic regimes and molasse sediments and uplifted coral reefs,
vegetation.Itisalsooneofthemoreisolated, thelatterpresentlocallyto1400mandoften
withadeepoceanictrenchalongthenorthern highly karstic (Audley-Charles, 1968; Mid-
sideoftheislandseparatingitfromtheInner dleton et al., 2006).
Banda Arc, a chain of volcanic islands that For biogeographers, the key points of
runs east from Flores and includes Lembata, interest are the age of subaerial emergence
Pantar,Alor,andWetar.Furthertothewest, andof subsequentuplift of Timor. These are
and again separated by very deep water, lie not known with any precision but are
Savu and Sumba islands, while to the south, constrained by stratigraphic and radiometric
more than 450 km across the Timor Sea, data.BerryandGrady(1981)datedthemain
extends the northwestern coastline of Aus- phase of deformation in the metamorphic
tralia. Timor has a significant satellite island Aileu Complex to between ca. 8 mya and
atitssouthwesternend—Roti,withanareaof 5.5 mya, and interpreted this phase as
1227km2andanelevationof430m.Thetwo marking the main arc-continent collision.
islands are separated by a 10 km wide strait Kaneko et al. (1987) suggested that exhuma-
with a sill depthof ca.100m. tion of the metamorphic belt doming com-
A high central massif running the full menced in the late Miocene in West Timor
length of Timor includes several peaks rising but attributed major uplift to doming and
6 BULLETIN AMERICAN MUSEUM OFNATURALHISTORY NO.341
high-anglefaultingoftheweldedsedimentary (Whitmoreetal.,1989;MartinandCossalter,
stackduringtheQuaternary,asaresponseto 1977, 1979). Above 1500 m, all forests
slab break-off of subducting Australian support a heavy mantle of mosses, lichens,
continental crust. Evidence of rapid uplift and epiphytes, giving way to mosses alone
of Timor through the Quaternary comes above1800m.Atthehighestelevations,high
from dated flights of coral terraces, with the wind shear creates stunted (elfin) tree com-
uplift rate during the late Quaternary esti- munitiesandpatchesoflowheathdominated
mated at0.5 m per1000 yrsfornortheastern by plants of ‘‘Himalayan’’ affinity (e.g.,
Timor (Chappell and Veeh, 1978). Even Rubusrosifolins,Ranunculusspp.).Mangrove
higher local rates are implied by de Smet et and beach communities occupy suitably
al.’s (1989) suggestion of more than 2 km of sheltered sites around the coastal margin.
uplift since ca. 5 mya in central West Timor. Today, most of the land below 1000 m
CLIMATE: Timor enjoys a tropical oceanic supports savannah woodland of casuarinas
climate but the pattern of rainfall is highly and eucalypts (mainly Eucalyptus alba),
variable, due to the complex interaction of usually with a weedy understory heavily
two monsoonal systems and local topogra- grazed by goats, cattle (mainly banteng or
phy (Monk et al., 1997). From November to Balinese cattle), and horses (Metzner, 1977).
May, monsoonal winds blow from the north This community presumably developed over
andbringthunderstormsandraintomostof millennia through the practice of traditional
the island but especially over the central shifting agriculture, which involves wide-
ranges. From June to October, offshore spread burning at the end of the dry season.
winds from northern Australia cross the Soil loss from steep slopes following initial
Timor Sea to bring rain to the southern side forest destruction has also contributed to a
of the central ranges. Mean annual rainfall radical change in the nature of the Timorese
ranges from less than 600 mm on the north environment and there is little evidence of
coasttoover3000mminmountainousareas regeneration to original forest types. In the
along the south coast. Mean daily tempera- mountainous regions, the creation of open
turesrangefrom23u–31uCinthelowlandsto pasture by repeated burning has converted
15u–24uCat1000m.Novemberisthehottest much of the adjoining forest to sclerophyll
month, and July the coldest. Precipitation communities dominated by E. urophylla.
generally exceeds evaporation between De- Commercial extraction of sandalwood (San-
cember and April, but there is a deficit talum album) over many centuries has also
between May and November (Monk et al., affected forest communities (WCMC, 1995)
1997). and there has been a recent sharp increase
VEGETATION: Less than 15% of the over the last few decades in the rate of
primaryforestcoverofTimorsurvivestoday deforestation,inresponsetobothpopulation
and even this is highly fragmented, with the growth and commercial plantations and
largest remnants mainly confined to the broad-acre agriculture (Bouma and Kobryn,
mountains and pockets along the south 2004).
coast. Monk et al. (1997) reconstructed the HUMAN PREHISTORY: The earliest evi-
original cover as a mosaic of evergreen and dence for human occupation of Timor dates
semievergreen rainforests, principally located to around 40,000 years ago (O’Connor and
alongthesouthernsideofthecentral ranges, Aplin, 2007), and there is growing evidence
and deciduous forests, with a largely com- for continuous occupation after that time, at
plementary northern distribution but also least in the coastal regions. The earliest
found on the southern coastal strip. Small populations presumably lived by hunting
pockets of mesophyll vine forest occurred in and gathering, possibly combined with basic
the southeast of the island. All forest com- arboriculture, with little archaeological evi-
munities above 600–1000 m were ever- dence for cultural or economic change prior
green, with broadleaf communities probably to the appearance of various ‘‘Neolithic’’
dominant. Drier sites probably supported markers (pottery, remains of various domes-
sclerophyllous vegetation featuring endemic ticates) in the late Holocene, dated to ,3500
Myrtaceae including Eucalyptus urophylla BP (Glover, 1986; O’Connor and Aplin,
2010 APLINAND HELGEN: NEW MATERIALOFCORYPHOMYS 7
Fig. 2. Map of Timorshowing the location of major townsand the various archaeologicalsites that
haveproducedfossil murineremains.
2007). A notable exception is the sudden yet turned up in any of the archaeological
appearance during the early Holocene of a assemblages. Exactly when and why these
New Guinean marsupial, Phalanger oriental- ‘‘megafaunal’’ species became extinct on
is, presumably as a consequence of increas- Timor is not known. However, if the extinc-
ing human interaction between the Lesser tions on Timor are linked to human activ-
SundaIslandsandMelanesia.Theremainsof ities,astheysooftenseemtobe(Burneyand
now-extinct rodents occur in all the exca- Flannery, 2005), we might reasonably postu-
vated sites, oftenco-occurringwith Neolithic late a longerhistory of humanoccupation of
artifacts and the bones of domesticates. The Timor.
same layers also contain the bones of two
commensal murines (Rattus exulans and R.
MATERIALAND METHODS
rattus) that probably accompanied early
agriculturalists into Eastern Indonesia some THE ARCHAEOLOGICAL SITES: The collec-
3500 years ago (Bellwood, 1997). Whether tions we studied come from excavations in
these co-occurrences faithfully reflect the nine archaeological sites, all located in East
survival of the ‘‘giant’’ rats into recent Timor (fig. 2). All the sites are shallow
millenniacannotbeanswereduntilsuchtime caverns or shelters developed in uplifted
asdirectradiocarbondatingisundertakenon coralline limestones. The sites are clustered
relevant bones and teeth. in five regions, as follows:
ThearchaeologicalrecordofFloresIsland
to the west features a much longer record of 1. Northern flank of the Baucau Plateau, west
of Baucau township on the north coast of
human occupation, with strong evidence for
East Timor. The plateau is approximately
initialcolonizationpriorto780,000yearsago
400 km2 in area and comprises a series of
(Morwood et al., 1998, 1999) and still
Quaternary coral limestone terraces that rise
controversial evidence for local evolution of from sea level to 500 m. Two sites were
a now extinct hominin species (Brown et al., excavatedbyIanGlover andhisteam.
2004; Morwood et al., 2004; Jacob et al., LieSiri(TL):alarge,opencavernlocatedjust
2006). To date, Timor has not produced any over 1 km from the coast, at an elevation of
evidence for a long history of human 240 m, and at approximately 8u269S,
occupation. However, it should be noted 126u229E. The cave deposit was excavated
toamaximumdepthof2.05mandproduced
that poorly dated Quaternary sediments
amaximumcarbon14(14C)determinationof
(Ainaro Formation of Audley-Charles,
7270 6 160 BP (ANU-236) from scattered
1968)onTimorhaveproducedfossilremains
charcoal fragments. Glover (1986) inferred a
ofthreelargevertebrates(apygmyprobosci-
basalageofca.10,000BPforthedepositand
dean Stegodon sp., a ‘‘giant’’ turtle, and a recognized a total of seven ‘‘horizons’’
‘‘giant’’ varanid lizard [Verhoeven, 1964; (number from deepest to most surficial;
Hooijer, 1969a, 1969b]), none of which have corresponding to sedimentological and cul-
8 BULLETIN AMERICAN MUSEUM OFNATURALHISTORY NO.341
tural subdivisions of the stratigraphic col- weski,1967),reinvestigatedbyGloverin1966
umn). Horizons Vc to VII contained pottery (Glover, 1986: 17) and then re-excavated by
and the remains of domesticates. Jaws and theANUteamin2000–2002.Thedeposithas
teeth of large murids were obtained from a complex stratigraphy and excavations in
horizonsIIto Vc. different parts of the site produced cultural
Bui Ceri Uato (TB): a large, open cavern and faunal assemblages that span three
located around 2 km inland, 175 m and at periods: from 30,000–35,000 BP; from
approximately8u279S,126u229E.Thedeposit 18,000–25,000 BP; and from ca.10,000 to
wasexcavatedtoamaximumdepthof1.45m, recent(O’Connoretal.,2002;O’Connorand
withatotalof10horizonsidentified.Pottery Aplin, 2007). Small samples of large murid
and bones of domesticates were found in remains were obtained from each strati-
horizons V to X and bones of large murids graphiccontext.
from horizons I to VI or VII. Glover Jerimalai (JM): This site is located close to
encountered problems with radiocarbon dat- Lene Hara but is at slightly higher elevation
ing of this site but more recent 14C determi- and somewhat further inland. Excavated by
nations place the basal layers of Bui Ceri O’Connor (2007) in 2005 to a maximum
Uato in the terminal Pleistocene (Selimiotis, depthof1.5m.Basal14Cdatesineachoftwo
unpublisheddatacitedbyOliveira,2006:95). excavatedpitsfallintherange37,000–39,000
BP, but most of the stratigraphic profile
2. Central highlands of East Timor at about spanstheterminalPleistoceneandHolocene.
600 m and just over 20 km from the nearest Small samples of large murid remains were
coast.Two siteslocated eastof the township obtainedfrom each stratigraphiccontext.
of Venilale, on the eastern side of Hatu
Ariana,were excavatedbyGlover. 4. Adjacent to Lake Ira Laloro, the largest
Uai Bobo 1 (TO1): a small, enclosed cave at freshwaterlakeinTimor,locatedatca.334m
approximately 8u389S, 126u239E. Excavation in Laute´m Province, central to the eastern
reached a maximum depth of 1.4 m, with a peninsula of East Timor. Two sites were
totalofeighthorizonsrecognized.Thelowest excavated by the ANU team in 2001. Both
14C date obtained is 3470 6 90 BP (ANU- cavesareinaclifflinelocatedafewhundreds
414), but Glover (1986: table 65) inferred a of meters from the northern margin of the
basalageofaround9000BP.Potteryandthe lakefloodplain.
bonesofdomesticateswasfoundinhorizons MatjaKuru1(MK1):alarge,opencavern,at
III to VIII, and bones of large murids from approximately 8u269S, 127u089E. Excavation
horizonsItoV.Verylargenumbersofbones reached a maximum depth of 1.55 m. The
of small murids and bats were found in basal part of the deposit is terminal Pleisto-
horizons I to IV; Glover attributed the cene, but the bulk of the sediments accumu-
accumulation of these remains to a nonhu- lated during the period 5600–4600 BP (Veth
man predator. We agree and suggest an owl etal.,2005).Largesamplesofmuridremains
asthe most likelyagent. were obtainedfrom theselevels.
Uai Bobo 2 (TO2): a small, enclosed cave Matja Kuru 2 (MK2): a large, open cavern
located adjacent to Uai Bobo 1. Excavation located a few hundreds of meters to the east
reachedamaximumdepthof4.9minaloose, of Matja Kuru 1. Excavation by the ANU
dry deposit. Thirteen horizons were distin- team reached amaximum depthof2 m.The
guished, with a 14C determination for Ho- sequence produced a basal date around
rizon I of 13,400 6 520 BP (ANU-238). 32,000 BP but features an apparent hiatus
Pottery and bones of domesticates were in deposition over the period 30,000–15,000
foundinhorizonsVIIorVIIItoXIIII.Large BP. Large samples of ‘‘giant’’ rat remains
muridswererecoveredfromhorizonsItoX. were obtainedfrom this site.
Alargequantityofsmallmammalboneswas
alsorecoveredfrom this site. 5. The Com area, on the north coast of the
easternpeninsula.
3. Coastal scarp at the eastern end of East Telupunu cave: a moderately large, open
Timor, in thevicinity ofTutualuvillage. cavern located approximately 5 km inland
LeneHara(LH):alarge,opencavernlocated from the coast, at 260 m, and at approxi-
about 5 km east of the village of Tutuala, mately 8u229S, 127u029E. Excavation by
100 m and at approximately 8u249S, Spriggs in 2002 reached a depth of 1.5 m.
127u169E. The site was excavated in 1963 by Thegreaterpartofthesequenceispreceramic
Antonio de Almeida (Almeida and Zbysz- and contains sparse cultural and faunal
2010 APLINAND HELGEN: NEW MATERIALOFCORYPHOMYS 9
remains, with a basal age of around 13,500 other craniodental elements including the
BP(Vethetal.,2005).Preservationoforganic premaxillaandupperincisor,andthefrontal,
remains including bone in this deposit is petrosal, and ectotympanic bones. The sec-
superiortothat ofallothers. ond specimen consists of a palate with
associated interorbital portionsof the neuro-
ASSOCIATION OF UPPER AND LOWER
cranium, referable to a species of Mahoney’s
DENTITIONS: Asreportedpreviouslybyboth
GenusB.Bothspecimenswillbedescribedin
Mahoney (appendix 3 in Glover, 1986) and
a later contribution of this series. Judging
Musser(1981b),theTimorese‘‘giant’’murids
from the relative abundance of the tooth-
fall into three major groups based on their
bearing elements, these two genera are the
dentalmorphology:(1)specimenswithhighly
most abundant taxa overall in the collection.
cuspidate, complex molars (Coryphomys and
Withthesespecimensasareferencepoint,the
Mahoney’sgenusA);(2)specimenswithhigh-
large number of dissociated specimens of
crowned, transversely laminate molars (Ma-
other bones could be assessed as to their
honey’sgenusB);and(3)specimenswithlow-
probableaffinity.Asaresult, itispossibleto
crowned molars with cusps fused into trans-
generically assign the majority of isolated
verse laminae (Mahoney’s genus C). Upper
upper incisors and premaxillae, frontal
and lower dentitions of each general group
bones, and petrosal bones, and to assign
are easily paired. However, Coryphomys and
some specimens to species level.
Mahoney’sgenusAaresimilaringeneralsize
The isolated petrosal bones from large
andmorphologyandgreatercareisneededto
murines showed striking morphological var-
correctly associate upper and lower molars.
iation and particular effort was made to
To do so, we paid attention to the following
allocate these elements. An initial analysis
attributesofthespecimens:(1)relativeupper
produced four morphological groups. One
and lower molar row lengths (in murines
well-defined group, represented by five ex-
lengthoftheuppermolarrowusuallyexceeds
amples, includes the petrosal associated with
that of the lower molar row, usually by 4%–
theburntcraniumofMahoney’sGenusA.A
6%); (2) the morphology and dimensions of
second distinctive group, including several
the upper and lower incisors (in murines
dozens of specimens, consists of petrosals
width of the upper incisors almost always
that are morphologically very similar to the
exceeds that of the lowers; one exception is
petrosal of Rattus norvegicus, albeit of much
Nesokia indica); and (3) the relative abun-
larger size. This group is referred with
dances of the various morphological forms confidence to Mahoney’s genus B, for two
recognized within the complex-toothed reasons: (1) this genus is also most abun-
group. Using these criteria, it is possible to dantlyrepresentedamongthejawsandteeth;
confidently associate upper and lower denti- and (2) its dental morphology also suggests
tionswith eachof theindividual species. an affinity with Rattus and its close allies
ALLOCATION OF DISSOCIATED CRANIAL (members of the Rattus Division, sensu
ELEMENTS: As is commonly the case with Musser and Carleton, 2005). The third and
archaeological assemblages, almost all the fourth groups are represented by three and
cranial specimens of the Timorese murines two petrosals, respectively. These groups
consistofindividualdissociatedelements,the presumably represent Coryphomys and Ma-
majority with some damage. In the present honey’s Genus C, the latter of which shows
collection, two partial crania are available, strong dental similarities with various Aus-
each referable to a different genus, and these tralo-Papuan murines including Uromys,
provide the key to allocation of other less Solomys,andMelomys.Petrosalsofthethird
complete specimens. One of the two partial group are referred with confidence to Maho-
crania is thoroughly burnt and fragmented ney’sGenusC,forthreereasons:(1)theyare
but could be reconstructed to provide an consistently smaller than petrosals of the
almost complete cranium belonging to Ma- fourthgroup (judging from mandible dimen-
honey’s Genus A. This specimen is critically sions, Genus C is a smaller murine than
important as it allows for direct association Coryphomys); (2) they do not show any
of an upper molar morphology with various significant variation in size or morphology
10 BULLETIN AMERICAN MUSEUM OFNATURALHISTORY NO.341
Fig. 3. Nomenclature of upper and lower molar crown structures in each of Lenothrix canus (after
Musser, 1981) and Coryphomys buehleri. A, upper molars of Lenothrix canus; B, upper molars of
Coryphomysbuehleri; C,uppermolars ofLenothrixcanus; D,uppermolarsofCoryphomysbuehleri.For
uppermolarsprincipalcuspsarenumberedaccordingtoMiller’s(1912)system;theseareidentifiedinthe
textwiththeprefix‘‘t.’’Abbreviation:pc,posteriorcingulum.Lowermolarcuspsarelabelledaccordingto
the system of Weerd (1976). Abbreviations: a-cen, anterocentral cuspid; a-lab, anterolabial cuspid; a-lin,
anterolingual cuspid; alc, anterolabial cusplet; alic, anterolingual cusplet; ed, entoconid; hd, hypoconid,
md, metaconid, pc, posterior cingulid; pd, protoconid;plc, posterolabial cusplet.
(consistent with the lack of significant size modified by Misonne (1969) and for the
variation in the dental sample of this taxon); lower molars on the terminology of Weerd
and (3) they are consistent in general (1976: 44). This terminology is illustrated
morphology with petrosals of Uromys and here (see fig. 3) for each of Coryphomys
Melomys. In contrast, the two petrosals of buehleri and Lenothrix canus, the latter to
the fourth group are larger, differ markedly identifystructuresthatarenotrepresentedin
in morphology from those of Uromys and the dentition of Coryphomys. Where appro-
Melomys, and differ considerably in size, priate,weidentifytheequivalentstructuresin
consistent with our identification of two alternative terminologies as used by others.
species within the Coryphomys sample. We use the term ‘‘lamina’’ to refer to the
None oftheabundantpostcranialremains more or less transverse rows of cusps that
from the various sites are associated with typify both the upper and lower molars of
other skeletal elements, either postcranial or murine rodents. The first upper molar has
cranial. Though great morphological diver- three such laminae (anterior, middle, and
sity is present in nearly every skeletal posterior) while each of thesecond and third
element, the task of allocating all of this upper molars has two laminae each. In the
dissociated postcranial material to particular lower molars, each tooth has two primary
taxa is one for the future. laminae that are also called ‘‘chevrons’’ in
TERMINOLOGYANDMEASUREMENTS:For some contexts; this is supplemented in the
naming the principal cusps and crests of the caseofthefirstlowermolarbyanadditional
molar teeth of Coryphomys spp. we have structure—the anteroconid—that is attached
followed the descriptive terminology em- to the front of the anterior lamina.
ployed by Musser in his numerous works Osteological terminology of the mamma-
(e.g., Musser, 1981a; Musser and Heaney, lian skull remains highly multifarious, with
1992), based for the upper molars on the many different terms often in use for what
system introduced by Miller (1912) and are undoubtedly homologous features in
