Thirty species of nautiloids and ammonoids were identified based on the material collected from peninsular Thailand. Ordovician nautiloids: a sactorthoceratid nautiloid (Sactorthoceras banestanensis) from Changwat Satun, from the western part of the peninsula and a ruedemannoceratid nautiloid (Mediganella magna), from Changwat Nakhon Si Thammarat from the eastern part of the peninsula. Devonian-Carboniferous ammonoid: Neoglyphioceras subcirculare from Changwat Satun. Triassic nautiloids: two orthoceratid nautiloids (Michelinoceras sp. A and Tienoceras sp. A), and two syringonautilid nautiloids (Syringoceras barrandei and Javavionautilus heterophyllus) from Changwat Phatthalung, in the eastern part of the Peninsular. Twenty-four species of ammonoids were collected from the same locality: one ophiceratid (Ophiceras connectens), one flemingitid (Xenodiscoides perplicatus), one meekoceratid (Juvenites canadensis), two paranannitids (Arianites musacchi and Epiceltites genfii), two ussurids (Ussuria sp. A and Ussaria sp. indet.), one noritid (Bosnites clathratus), one acrochordiceratid (Paracrochordiceras sp. indet.), nine ceratitids (Kellnerites bosnensis, Halilucites sp. A, Halilucites sp. B, Eutomoceras aff. laubei, E. dunni, Eutomoceras sp. A, E. sp. B, E. sp. C, E. sp. D), one hungaritid (Hungarites sp. A), one aplococeratid (Aplococeras parrus), one celtitid (Indoceltites trigonalis), one nannolytoceratid (Audaxlytoceras audax) and one protetragonitid (Protetragonites sp. A). All these cephalopods are recorded for the first time in Thailand.
The peninsular Thailand is the center of the Shan-Thai block (Bunopas and Vella 1983). The Paleozoic and Mesozoic rocks in peninsular Thailand are the Phuket Mountain range and the Nakhon Si Thammarat Mountain range (Fig. 1), distributed in the north–south axis along the peninsula. Cambrian rocks are present in the southwestern coast of the peninsula, on Tarutao Islands and Changwat Satun on mainland (Pungrassami 1983; Wongwanich et al. 2002; Cocks et al. 2005). The Ordovician Rocks are shales and limestones of deep-water facies, which are 900–1040 m thick and occur in the lower part of the peninsula (DMR 2013). The system consists mainly of the carbonatic Thung Song Group which can be subdivided into seven formations (Wongwanich et al. 1983, 1990; DMR 2001; DMR 2013). The Rung Nok Formation is Early to Middle Ordovician and occurs in Thung Song, Changwat Nakhon Si Thammarat (10°N, 99′E) (the fourth locality of this study) in the northeastern part of the peninsula and La-gnu, Changwat Satun in the southwest (6°N, 102′E). The uppermost Ordovician strata presented at the latter locality have been proposed as Pa Kae Formation (Wongwanich et al. 1983; DMR 2001) (Table 1). The Ordovician and Silurian boundary is about 10 km away in the Thong Pha Phum Group (the first locality). The nautiloid Manchuroceras has been recorded from the Ordovician carbonate in the peninsula (Stait and Burrett 1984). No Ordovician fossils younger than Whiterockian were found.
The Thong Pha Phum Group in the lower part of the peninsula consists of sandy marl, black shale, calcareous siltstone and nodular limestone (Bunopas 1983; DMR 2013). The age of this group is still uncertain (DMR 2001). The group is subdivided into three formations (Table 1) with uncertain age; Wang Tong Formation of Late Ordovician to Early Silurian age, Kuan Tang Formation of Late Silurian to Early Devonian age and Pa Samed Formation of Early Devonian to Early Carboniferous age (Bunopas 1983; Wongwanich et al. 1990) (the second locality). Cephalopod fossils have been recorded in the upper member of the shallow-water facies.
The Lampang Group is Permian with the Phanom Wang Formation, which crops out in the east-central part of the peninsula (Chonglakmani 1983; Raksakulwong 2002). Nautiloids have been recorded from Permian Rocks. Chaiburi Formation is the only Triassic stratigraphic unit of this group (Ampornmaha 1995); it occurs only in Changwat Phattalung (the third locality). This formation consists of three members (Table 1); Phukhaothong Dolomite, Chiak Limestone and Phanomwang Limestone Members (Ampornmaha 1995; Sardsud 2001; Meesook et al. 2002; DMR 2013). Fossils of conodonts, radiolarians and early reptiles have been recorded from these carbonate formations (Ampornmaha 1995; Bunopas 1983; Sardsud 1997, 2001, 2002).
Cephalopod fossils in Thailand, especially in peninsular Thailand are known from only a few localities. The first record was about three species of Carboniferous ammonoids by Reed (1920). At present, the cephalopods recorded from Thailand comprise some 133 species (Reed 1920; Brown et al. 1951; Kummel 1960; Pitakpaiwan et al. 1969; Teraoka et al. 1982; Chonglakmani 1983; Stait and Burrett 1984; Glenister et al. 1990; Ishibashi and Chonglakmani 1990; Ingavat-Helmcke 1994; Ishibashi et al. 1997; Fujikawa et al. 1999, 2005; Fujikawa and Ishibashi 2000; Wongwanich et al. 2004; Zhou and Liengjarere 2004; DMR 2006; Hirsch et al. 2008; Ridd et al. 2011; Kozai et al. 2011). The nautiloids found in Thailand belong to 4 subclasses, 6 orders, 11 families, 15 genera and 21 species. Ammonoids discovered in Thailand were assigned to 1 subclass, 5 orders, 40 families, 71 genera and 112 species. Of these 133 species recorded in Thailand, only 14 of nautiloids and 10 of ammonoids are from peninsular Thailand.
In peninsular Thailand, the previous records of fossil cephalopods were distributed over 24 species. Nautiloids have been recorded only from the Ordovician and ammonoids from the Carboniferous and Permian. The first record of nautiloids was Actinoceras sp. from Changwat Nakhon Si Thammarat, in the eastern part of the peninsula (Brown et al. 1951). Pitakpaiwan et al. (1969) reported Armenoceras cf. chediforme Kobayashi, 1958 from the same locality (including three unidentified Middle Ordovician nautiloids) Changwat Satun, in the western part of the peninsula. Changwat Satun has been the source locality for several nautiloids: Michelinoceras sp., Sinoceras chinense (Foord, 1888) (Stait and Burrett 1984), one endoceroid from the Thung Song Formation (Teraoka et al. 1982), Wutinoceras sp., Endoceratidae indet., Chaohuceras sp., Hardmanoceras chrysanthemum (Kobayashi, 1959), Machuroceras nakamense Stait and Burrett, 1984 (Stait and Burrett 1984; DMR 2006), Actinoceras sp., Armenoceras sp., Georgina sp. and one ormocerid. (Ingavat-Helmcke 1994).
The first cephalopods recorded in peninsular Thailand were Carboniferous ammonoids from Changwat Phatthalung in the eastern part of the peninsular, described by Reed (1920) as Glyphioceras? sp., Prolecanites? sp. and Pronorites aff. cyclolobus (Phillips, 1836). Wongwanich et al. (2004) recorded Syngastrioceras sp. and Stenopronorites aff. uralensis (Karpinsky, 1889) from the Lower Carboniferous of Changwat Satun. From the Lower Permian, Fujikawa et al. (2005) reported five ammonoids from Changwat Phatthalung, Agathiceras aff. suessi Gemmellaro, 1887, A. girtyi (Bose), Agathiceras? sp., Adrianites sp. and Miklukhoceras sp.
Since most palaeontological studies in Thailand have been focused on macro-vertebrates, dinosaurs and fish, the authors aim to raise the renewed interests in fossil invertebrate systematics. This study focuses on taxonomic identification and the description of diversity of cephalopod fossils of the region. However, available materials, particularly ammonoids, are limited to the Ordovician to Triassic, excluding the Permian, Jurassic and Cretaceous and Cenozoic. Therefore, it does not represent the majority of cephalopods diversity in the region. Much more materials are to be discovered and much more publications will follow.
Thai words used in the text are Khao (=Mountain), Muang (=City), Amphoe (=District) and Changwat (=Province).
Materials and methods
The materials are from unsorted collections of the Palaeontological Research and Education Center, Mahasarakham University (PRC), Changwat Mahasarakham (northeastern Thailand); Princess Maha Chakri Sirindhorn Natural History Museum, Prince of Songkla University (PSUNHM), Changwat Songkhla (southeastern Thailand); and Natural History Museum, Kampangwitaya School (ISI), Changwat Satun (southwestern Thailand). Specimens of PRC and PSUNHM were collected by the third author (PS) during 1973–1974 as unidentified outcrop fossils. Specimens of ISI were collected from Changwat Satun by the fourth author (TN) in 2004.
A total of 808 specimens of nautiloids and ammonoids were collected from four localities in peninsular Thailand (Fig. 1). The first locality is Khao Noi (06°58′N, 99°46′E), Amphoe Langu, Changwat Satun. The Upper Ordovician (Caradocian to Ashgillian) deposits are included in the Pa Kae Formation, Thung Song Group. The second locality is Khao Banhan (6°56′N 99°47′E) in Ban Han, Amphoe La-ngu, Changwat Satun, Lower Carboniferous (Table 1) deposits are included in the Pa Samed Formation, Thong Pha Phum Group. These two localities are in the western part of the peninsula on the Andaman Sea coast, Indian Ocean . The third locality is Khao Ok-thalu (07°37′N, 100°5′E), Amphoe Muang Phatthalung, Changwat Phatthalung, Phukhaothong Dolomite, Chaiburi Formation, Lampang Group, Early to Middle Triassic (Anisian) (Ampornmaha 1995). The fourth locality is Khao Phanomsherd (08°09′N, 99°51′E), Amphoe Ronphibun, Changwat Nakhonsrithammarat, Rung Nok Formation, Thung Song Group, Lower Ordovician (Arenigian). The two latter localities are in the eastern part of the peninsula on the Gulf of Thailand coast, South China Sea, Pacific Ocean.
The terminology of morphology and measurements essentially follows Arkell et al. (1957) and Teichert et al. (1964). The description of nautiloids was made using the following abbreviations: (Pl) Phragmocone length, (Paw) Phragmocone anterior width, (Ppw) Phragmocone posterior width, (Cl) Chamber length, (Spd) Siphuncle diameter, and (Sl) Septal neck length. The description of the ammonoids was made using the following abbreviations: (Md) Maximum diameter, (Wh) Whorl height, (Ww) Whorl width, and (Ud) Umbilical diameter.
All specimens have been deposited in the reference Collection of the Palaeontological Research and Education Center, Mahasarakham University (PRC) and the Princess Maha Chakri Sirindhorn Natural History Museum, Prince of Songkla University (PSUNHM) and the Natural History Museum, Kampangwitaya School, (ISI).
Remarks: The specimen cannot be identified to species level because only one chamber of the phragmocone is preserved and the internal characters are incomplete (a perforate chamber and septal neck of the siphuncle are preserved).
Material: 1 specimen (PRC-SKM-KO-151), phragmocone length 17 mm, dolomite rock, Phukhaothong Dolomite Member, Chaiburi Formation, Triassic, Khao Ok-Thalu, Changwat Phatthalung, 7º37′N, 100º5′E, collector P. Srisuk.
Remarks: The present Early Triassic specimen differed from T. lenticulare Chao 1954, Permian, in its flatter and depressed round shape of the dorso-ventral cross section and the central position of the siphuncle compared to the lenticular cross section and subcentral siphuncle of T. lenticulare (Chao 1954).
Family Sactorthoceratidae Flower, 1946.
Genus Sactorthoceras Kobayashi, 1934.
Type species:Sactorthoceras gonioseptum Kobayashi, 1934.
2006 Sactorthoceras cf. banestanensis Evans, Evans in Danstanpour et al., Fig. 2, p. 340, Fig. 3, p. 343.
Material: 1 specimen (ISS-LN-ST-024), phragmocone length 69 mm, Pa Kae Formation, Thungsong Group, Ordovician, Khao Noi, Changwat Satun, 6°58′N, 99°46′E, collector T. Nutadhira.
Remarks: The present specimen is similar to S. banestanensis Evan, 2006 from the late Early Ordovician (Caradoccian) of Kerman, East-Central Iran (Dastanpour et al. 2006, Fig. 3, p. 343). However, the size of the septal foramen of the present specimen was smaller (5.5 vs. 13.3 %), while the chamber length was longer (19 vs. 15 %) and the septal neck was longer (6 vs. 3.7 %).
Subclass Nautiloidea Agassiz, 1847.
Order Discosorida Flower, 1950.
Family Ruedemannoceratidae Flower, 1940.
Genus Madiganella Teichert and Glenister, 1952.
Type species:Madiganella magna Teichert and Glenister, 1952.
Madiganella magna Teichert and Glenister, 1952 (Fig. 2k, l)
1957. Madiganella magna; Flower and Teichert, pl. 4, Fig. 7, p. 24.
1964. Madiganella magna; Teichert et al., Fig. 2a, b, p. K329.
Material: 2 specimens (PRC-SHM-KPC-002 and 003), phragmocone length 23.3–31.0 mm, Rung Nok Formation, Thungsong Group, Ordovician, Khao Phanom-Sherd, Changwat Nakhon Si Thammarat, 8°09′N, 99°51′E, collector P. Srisuk.
Remarks: The chamber length of M. magna (see Teichert et al. 1964; Fig. 2a, b, K329) is about 10.7 % of the phragmocone width, but that of the present specimen is about 5.3 %.
Order Nautilida Agassiz, 1847.
Family Syringonautilidae Mojsisovics, 1902.
Genus: Syringoceras Hyatt, 1894.
Type species: Ammonites? granulosostriatus Klipstein, 1843.
1957. Xenodiscoidesperplicatus; Arkell et al., Fig. 169, 2, p. L137.
Material: Two specimens (PRC-SHM-KO-060, PRC-92), diameter 24.7 mm, dolomite rock, Phukhaothong Dolomite Member, Chaiburi Formation, Triassic, Khao Ok-Thalu, Changwat Phatthalung, 7º37′N, 100º5′E, collector P. Srisuk.
Remarks: Four ribs on the outer whorl near the aperture of the present specimen were thicker than the other ribs and were expanded on the middle of the flank. Such features are absent in the specimen figured by Arkell et al. (1957; Fig. 169, 2, p. L137).
Material: 4 specimens (PRC-SHM-KO-020, 083, 314; PSUNHM-2297-505-040), diameter 5.3–10.1 mm, dolomite rock, Phukhaothong Dolomite Member, Chaiburi Formation, Triassic, Khao Ok-Thalu, Changwat Phatthalung, 7º37′N, 100º5′E, collector P. Srisuk.
Remarks: Three lateral saddles present in the available specimens compared to only two in other species of the genus. Lobes and saddles are serrated in other species of the genus but smooth in present specimens.
1957 Kellnerites bosnensis; Arkell et al., Figure 183, 1, p. L151.
1964 Kellnerite cf. bosnensis; Bando, pl. 5, Fig. 6, p. 147.
1993 Kellnerites bosnensis; Brack & Rieber, pl. 5, Figs. 7–10, 13–14, p. 509.
Material: Three adult specimens (PRC-SHM-KO-131, 156, 296) and 17 juveniles (PRC-SHM-KO-022, 101, 148-1, 148-2, 148-7, 148-8, 194, 353, 358, 369, 414, 417, 459, 628, 633, 634; PSUNHM-2297-505-152), diameter 19.8–31.8 mm in adult and 3.7–13.3 mm in juvenile, dolomite rock, Phukhaothong Dolomite Member, Chaiburi Formation, Triassic, Khao Ok-Thalu, Changwat Phatthalung, 7º37′N, 100º5′E, collector P. Srisuk.
Remarks: The ribs of the adult K. bosnensis in Bando (1964; pl. 5, Fig. 6, p. 147) are branched and had three tubercles, but only two in the present “juvenile” specimens. The keel is blunt in all the present specimens.
Material: Two specimens (PRC-SHM-KO-084, 395), diameter 6.8–17.3 mm, dolomite rock, Phukhaothong Dolomite Member, Chaiburi Formation, Triassic, Khao Ok-Thalu, Changwat Phatthalung, 7º37′N, 100º5′E, collector P. Srisuk.
Remarks: Falcoid ribs of the present specimens differ from falcate ones of other species of the genus. Absence of nodes is a similar characteristic to other species of the genus, but ribs are concave, pronounced.
1914 Eutomoceras laubei; Smith, pl. 10, Figs. 7–11, p. 160, pl. 14, Fig. 8–8a, pl. 24, Figs. 7–9, p. 174, pl. 27, Figs. 1–13, p. 177, pl. 90, Figs. 1–4, p. 238.
Material: 1 specimen (PRC-SHM-KO-322), diameter 13.0 mm, dolomite rock, Phukhaothong Dolomite Member, Chaiburi Formation, Triassic, Khao Ok-Thalu, Changwat Phatthalung, 7º37′N, 100º5′E, collector P. Srisuk.
Remarks: The external morphology of the present specimen is similar to E. laubei Meek, 1877 (Smith 1914; pl. 27, Figs. 5–10, p. 177), except for the presence for the bituberculation on the apertural zone of the third whorl.
Remarks: The lobes of the suture line are serrated in H. yatesi (Hyatt and Smith 1905, pl. 20, Figs. 1–4, 257 p.), but the lobes are smooth in the present specimens. Other characteristics resemble H. yatesi.
Family Aplococeratidae Spath, 1951.
Genus Aplococeras Hyatt, 1900.
Type species:Dinarites avisianus Mojsisovics, 1882.
1982 Aplococeras parvus; Silberling and Nichols, pl. 22, Figs. 18–23; text-Fig. 38, p. 53.
Material: 387 specimens (PRC-SHM-KO-021 to 668; PSUNHM-2297-505-003 to 151), diameter 3.1–13.9 mm, dolomite rock, Phukhaothong Dolomite Member, Chaiburi Formation, Triassic, Khao Ok-Thalu, Changwat Phatthalung, 7º37′N, 100º5′E, collector P. Srisuk.
Remarks: The overall shell shape and septal suture line elements of present specimens are similar to A. parvus (Silberling and Nichols 1982, pl. 22, Figs. 18–23; text-Fig. 38, p. 53), but the 1st lateral saddle is smaller than the ventral one, that is equal in the type specimen.
Material: Two specimens (PRC-87, 88), diameter 16.6–20.0 mm, dolomite rock, Phukhaothong Dolomite Member, Chaiburi Formation, Triassic, Khao Ok-Thalu, Changwat Phatthalung, 7º37′N, 100º5′E, collector P. Srisuk.
Remarks: The overall characteristics of the present specimens are similar to P. crebrisulcatus. The latter species has dense ribs on the inner and outer whorls (Nagy 1967; pl. 3, fig. 2, p. 76, pl. 4, Fig. 3, p. 77), but those ribs are absent in the present specimens.
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The authors would like to thank the Palaeontological Research and Education Center, Mahasarakham University, Thailand, for the loan of specimens included in this study. We also thank the staff of the Excellence Centre for Biodiversity of Peninsular Thailand, Department of Biology, and Princess Maha Chakri Sirindhorn Natural History Museum, Faculty of Science, Prince of Songkla University for their assistance in the laboratory work. Our warmest thanks are dedicated to Janek von Byern (Core Facility Cell Imaging and Ultrastructure Research), Leopold Krystyn and Christian Baal (Faculty of Earth Science, University of Vienna). Our grateful thanks are for Alexander Lukeneder (Naturhistorisches Museum Wien), Attila Vörös (Hungarian Natural History Museum) and René Hoffmann (Department of Earth Science, Freie Universität Berlin) for their supervision. We also wish to gratefully acknowledge Christian Klug (University of Zurich, Switzerland) for his many helpful suggestions and comments resulting in a substantial improvement to the quality of the manuscript. This work was also supported by the Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission and ASEA-UNINETS research grant.
Authors and Affiliations
Department of Biology, Faculty of Science, Prince of Songkla University, Hatyai, Songkhla, 90112, Thailand
Excellence Centre for Biodiversity of Peninsular Thailand (CBIPT), Faculty of Science, Prince of Songkla University, Hatyai, Songkhla, 90112, Thailand
Palaeontological Research and Education Center, Mahasarakham University, Kantarawichai, Mahasarakham, 44150, Thailand
Natural History Museum, Kampangwittaya School, La-gnu, Satun, 91110, Thailand
Department of Mining and Materials Engineering, Faculty of Engineering, Prince of Songkla University, Hatyai, Songkhla, 90112, Thailand
Tongtherm, K., Nabhitabhata, J., Srisuk, P. et al. New records of nautiloid and ammonoid cephalopod fossils in peninsular Thailand.
Swiss J Palaeontol135, 153–168 (2016). https://doi.org/10.1007/s13358-015-0108-8