Field notes on the fossil localities in northern Thailand visited Title during the field season of February 1999 Kunimatsu, Yutaka; Saegusa, Haruo; Nakaya, Hideo; Author(s) Ratanasthien, Benjavun; Nagaoka, Shinji; Tsubamoto, Takehisa Citation Asian paleoprimatology (2000), 1: 115-136 Issue Date 2000 URL http://hdl.handle.net/2433/199737 Right Type Departmental Bulletin Paper Textversion publisher Kyoto University Asian Paleoprimatology, vol. 1:115-136 (2000) Kyoto University Primate Research Institute Field notes on the fossil localities in north r'.Thailand visited durk 7, the field season of February 1999 Yutaka Kunimatsul, Haruo Saegusa2, Hideo Nakaya3, Benjavun Ratanasthien4, Shinji Nagaoka', and Takehisa Tsubamoto6 1Primate Research Institute , KyotoUniversity 2HyogoPrefectural Museum of Man and Nature 3Facultyof Engineering, KagawaUniversity 'Departmentof GeologicalSciences , ChiangMai University 5Facultyof Education , NagasakiUniversity 6GraduateSchool of Science, Kyoto University Abstract In February1999, we visitedseveral fossil yielding areas in northernThailand. These areas,except for the HabPu DaiCave Deposit locality, are of Mioceneage (Ducrocq et al. 1994,Saegusa et al. 1999).A numberof fossilswere collected at theselocalities during our fieldworkin February1999. The most extensively examined areas were Mae Soi and Sob MaeTham, where we recognized17 and20 fossillocalities, respectively. Our field survey suggeststhat thereis stilla goodpossibility to findnew fossil sites in northernThailand. In thisarticle, we providefield information on eachof thesefossil localities. 1. Introduction In the northern part of Thailand, around Chiang Mai, there are a number of intermon- tane basins where Miocene sediments were accumulated. Miocene fossil remains have been reported from this area by previous authors (e. g. see Ducrocq et al. 1994 and refer- ences cited in it). Among them is a non-cercopithecoid catarrhine named Dendropithecus orientalis (Suteethorn et al. 1990). This taxon is represented only by a single lower molar at present, and its assignment to the genus Dendropithecus is doubted (Harrison & Gu 1999). However, the presence of this fossil primate in Thailand is of interest, because compared to relatively large numbers of Neogene catarrhine fossils discovered in China to the east and in Indo-Pakistan to the west, very little is known on their evolution during the late Cenozoic in Southeast Asia. Therefore, further paleontological fieldworks are needed in this region. During the field season of February 1999, we carried out our fieldwork at several areas in northern Thailand, most of which are estimated as Miocene in age (Fig. 1). ough 115 Y. Kunimatsu et al. 98° 100° 20°NI. Chiang Rai IP Phayao 100kmillin al • Pong VIP ChiangMai0Chiang • Muan hiang0Mai 1 L i'.\,:Phitsrulok arn•ang • (ThMaeMoh Bangkok 18Mae Soi 0 tHab Pu Hai .... Sob Mae Thamt Li r,9 ukhothai 10 '. Phitsanulok - ) Figure1. Blackcircles indicate the fossil yielding areas that we visitedduring the field season of February 1999 innorthern Thailand. our fieldwork, a certain number of fossils were recovered. This article aims to keep the records of the information on the fossil localities that we visited during this field season. A short description of each locality is given with the latitude and longitude measured by global positioning system (GPS: Gamin GPS II, datum WGS84), when available. 2. Notes on the fossil localities 2-1. Mae Soi (Fig. 2 & 3) Mae Soi is a village near Chom Thong about 60 km southwest of Chiang Mai. The village is located on the way from Chom Thong to Hot. In 1997, local people discovered fossilized proboscidean bones on a hill west of the village. The hill, by chance, is called Doi Chang (= Elephant Hill). They brought the fossils to a local temple in order to hold a religious service for the spirit of this ancient animal. After the ceremony, most of the fossils were buried again in the original place (DCh1), but some of them were sent to the National Museum in Chiang Mai for a scientific investigation. Then, the director of the Museum informed one of the authors (B. Ratanasthien) of the discovery of the probos- cidean fossils in Mae Soi. Consequently, Ratanasthien and her Japanese colleagues (H. Saegusa & H. Nakaya) recognized the importance of the specimen, and started excavating the rest of the specimen at Doi Chang in 1997 (Saegusa et al. 1999). The excavation was 116 _ j • Fossil Localities in Northern Thailand ( o<44°V \"\ ° c.,\\0<(Mae\.• Nam Ping Dal Chang ----::/- ,---" • ..- . _ -------N ---___-• Y -- -- Ga.,•-•./A. - ./ •A e.. _.../ \.... 'k ..-------........,„ \ f i ,....--••_-- •••...,..,_ Ban Mae Soi N , __>___..• . Kew Hoi Tal\\ '\ N -. .\\'\ ''. i , , ^_, . , .„ •••-- -.... .. ,.. 1 • .. ^,, ,., ; \ •. '!: .N. , .c. \ k ) \ \ k ! \\ \ •29'L) .,:\ \ ...) , `t\ 1\\' c,4 • 1 km ^....\,-.. 98°35' 98°40' - ( 4,-,---_-,.,-....-,....-- Figure 2. Fossil yielding subareas in the Mae Soi area, near Chom Thong, in the Chiang Mai Province. - .."-- ......„2.%,--- - ), i/ ..------ . • • 1 1, tr:. -- -..,. )°*'"7 .1s,ts i 446 . ° '-,-)67.IFigure 3.Fossil localities inthe Doi ......4‹:-------"") ,. ........Chang and Kew Hoi Tal subareas. ®®-.I 6 f" .....2,e The Arabic and Roman numbers .....• indicatethe fossil localities with the prefix DCh (Doi Chang)and with .../(::!)IquirkK„.,,.....-,-,„Eu the prefix KHT(Kew Hoi Tal) , re- °N. 500 m spectively. \, ..1'`‘C-•,- completed in the next field season (February1999), and all the remains of the probos- cidean fossilwere broughtto the NationalMuseum in ChiangMai. In addition,during the field season of February 1999,we carriedout surface collectionat a number of localities in Doi Changand Kew HoiTal (a small hill ca. 500 m southof Doi Chang). From the main road throughfarms of longans,one can accessup to the vicinity of Doi Changby car. We usually parked our vehicle besidea smallpond. We calledthis parking place as the Road End (CAPS data: N 18° 17' 06.7" E 98° 36' 50.8"). From the Road End to Doi Chang was about 15 minuteswalk. The descriptionof each locality in this area is as follows. 117 / ) ) 2 Kunimatsu et al. ^ WAT ?VOW' ,,,;1412174 19 tICATC1„ 47 44i5 -;f!:'2 V' erg' •n Figure 4. Doi Chang (= Elephant Hill) and the locality DCh1 viewed from the locality KHT1 (= from the south). Between DCh1 and KHT1 lies the locality KHT2. 2-1-1. Subarea: of Chang (Locality Prefix: DCh) (FN. 4) Locality DCh1 (GPS data: N 18° 17' 10.5" E 98° 36' 28.7"): Another name is "Mast- odon Site". The skull, upper half of the body and pelvis of a tetralophodont gomphothere were recovered during the field season of 1997. In the present season, the remaining ribs were excavated. In addition, the hindlimbs were discovered by ca. 5 m west of the upper part of the body. Probably, the skull, ribs, vertebrae, pelvis and these hindlimbs belong to the same individual of the larger species among the two proboscidean taxa in Mae Soi. The gomphothere skeleton was preserved in the lowermost part of a yellowish sandstone layer, which is underlain by a pale-colored silt layer. Some bone fragments were collected on surface, among which a phalanx of a perissodactyl was included. Locality DCh2 (GPS data: N 18° 17' 15.3" E 98° 36' 25.3"): This locality lies near the top of the Doi Chang hill. The surface is gently sloping southwards. The sediments are intercalated sandstone and reddish silt. We found fossils such as a tragulid mandibular fragment with teeth, a deciduous molar of a gomphothere, and fragments of turtles. Locality DCh3 (GPS data: N 18° 17' 20.2" E 98° 36' 27.5"): This locality is a slope a few tens of meters east of the locality DCh2. Petrified woods were found on surface around the lower part of the slope on 10th February. On the next day, rhinocerotid dental remains 118 Fossil Localities in Northern Thailand A se •.„ I ,N,K1 mt, , Figure 5. Petrified woods at the locality DCh7. were discovered near the top of the slope, along with fragments of proboscidian teeth and of turtles. Locality DCh4 (GPS data: N 18° 17' 09.8" E 98° 36' 32.7"): This is a small outcrop along the footpath coming from the Road End to the locality DCh1. Nakaya and Saegusa discovered rhinocerotid fossils on the way back to the Road End on 12th February. Yel- lowish and reddish sandstones are intercalated. Locality DCh5 (GPS data: N 18° 17' 10.4" E 98° 36' 30.2"): This locality is close to the "Mastodon Site" (DCh1), only a few tens of meters away to the east, and is separated from the latter by a gully. This locality was not productive in fossils. A bone fragment in yellowish sandstone matrix was found on 12th February, and additional bone fragments of large-bodied mammal were collected on the next day. Locality DCh6 (GPS data: N 18° 17' 07.9" E 98° 36' 31.3"): This locality lies above a small cliff a few tens of meters east of the locality DCh5. A fault runs between the locali- ties DCh5 and DCh6. Dark-colored petrified woods were found on surface. They were fractured into small fragments. The surface is yellowish fine sand with a lot of whitish pebbles. Locality DCh7 (GPS data: N 18° 17' 16.4" E 98° 36' 18.1"): This is a locality of 119 Y Kunimatsu et al. „ „..... ip':„*.. '..-','0- '.i '' •1: - '1''.:-.< ' 40, , „---., ' ' ,; ,:'' '' ,'-' $.ir,4:‘, iz,,?.; _.',. :tt, , 4A.'k.„"1:!...-d„re,,i”'i.,!. ' _Se:', 0,4ti , ,,, 71,, ....'.1- ..,j, ,,V;,.7.15., .;.,.,,,4•,./ ., L „. ...,.va,P.,', - kkt.'V 7w:ti , Figure6. LocalityIHT3. One of us(T. Tsubamoto) excavating a proboscidean humerus. 5). It is located on a ridge, ca. 50r-r, m west ere rela- tively woods (Fig.Some I. l tivey arge fragments,but theirlengths were ca.30 cm at largest. of t thetshuemmmwi t of Doi i Dark-colored Chang. petrified woods were scattered on surface. • l Locality ocality is a few tens DCh8 (GPS data: N 18° 17' 19.6" E 98° a 36' 33.5"): Thisth which o metersofeast goesofthe hill top downhill.of the local Small fragments of petrified woods wereeitcollectedy DCh 3' olnonsugrfaafcootpa e.