MIOCENE PLEUROTOMARIIDAE FROM NANTOU PREFECTURE, CENTRAL TAIWAN. 1

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1 Bull. Chin. Malacol. Soc. 中國貝詰 2:21-31 (1 975) MIOCENE PLEUROTOMARIIDAE FROM NANTOU PREFECTURE, CENTRAL TAIWAN. 1 C. C. Lin Department of Geology, National Taiwan University Taipei, Taiwan, R. O. C. ABSTRACT The famous living fossil Pleurotomaria are very rare in Cenozoic strata and modern sea. Taiwan is one of the five irnportant localities of the living Pleurotomaria in the world. The other localities are Japan, West Indies, Indonesia, and southern Africa. Four of the fifteen living species were found from Taiwan: Entemnotrochus rumphii (Schepman), PerotrochuHeramachíiKuro 曲, Mikadotrochus salmiana (Rolle) and!vl. hirasei ( 即如 y). No fossilpleurotomaria has been reported from Taiwan before. Three new species of Miocene Pleurotomaria to be described were collected by Mr. and Mrs. Chang-wu Pan from the middle? Miocene Nankang Formation of Chungliaohsiang, Nantou Prefecture, central Taiwan in Feb In honour of the collectors and fossillocality, 1 wish tω O name them a 泌 s siuyingae 2 Perot 佇 roc 吶 huωsnaωant, 的 ouen. 衍 s 的 s ACKNOWLEDGEMENTS 前 le writer expresses his sincere thanks to Mr. and Mrs. Chang-wu Pan, who offered such interesting, rare and important fossil pleurotomariids for my study. 1 would also like to thank Drs. H.Oz 也 i, S. Hayasaka, I. Fujiyama and M. Omori for their literature survey. Acknowledgement is also due to the National Science Council for supporting this study. lreport of "the Choshui and Tatu River Valley Project in Environmenta1 and Anthropological Research", sponsored by the National Science Counc i1. 2 Living P1eurotomariids are: Perotrochus Quoyana (Fischer and Bernard, 1856): P. africanus (Tomlin, 1948), P. teramachii Kuro 曲, 1955 ; P. geml 掏出 yer, 1965; P. lucaya Bayer, 1965; P. midas Bayer, 1965, P. pyramus Bayer, 1967; P. atlanticus Rios and Matthews, 1968; Mikadotrochus beyrichi (H i1gendorf, 1877); M. hirasei (Pi1sbry, 1903); M salmiana (RoUe, 1899); M. schmalzi Shikama, 1961; M. amabilis Bay 缸, 1963; Entemnotrochus adansonianus (Crosse and Fischer, 1861); 互 rumphii (Schepman, 1879). Among these, Mikadotrochus salmiana and M schmalzi may be synonymous.

2 22 C. C. Lin FORMER STUDlES ON NEOGENE PLEUROTOMARIIDAE FROM EASTERN ASIA ln 1955, T. Kuroda expressed the view that Tertiary and recent Pleurotomariidae should be separated from those of Mesozoic and Paleozoic species, because of their different special characteristics and different geologicaj age, and the modern forms can be represented by three genera: Perotrochus P. Fischer 1885, Mikadotrochus Lindholm 1927, and Entemnotrochus P. Fischer, His opinion was accepted by most Japanese malacologists and paleontologists. Treatise on Invertebrate Paleontology" Part 1, Mollusca 1, written by L.R. Cox, Brookes Kn ight et al.,directed and edited by Raymond C. Moore, 1960 also followed Kuroda's opinion. But R. Tucker AbL ott (1 974) considered E 川 emnotrochωand Mikadotrochus as subgenera under Perotrochus. Kuroda's above opinion is to be accepted by the author in his report. Tertiary pleurotomarian fossils in East Asia have been found only in Japan before. In 1932 Shichihei Nomura and Hiroshi Niino first reported 4 deformed specimens of Pleurotomariayabei Nomura and Niino (or Mikadotrochus yabei (Nomura and Niino)) from the Miocene Shirahama Group of Izu Peninsula and the Hakone district, Central Japan. ln 1954, Hiroshi Ozaki described Pleurotomaria prope-hirasei Ozaki (or Perotrochus prope-hirasei (Ozaki)) from the basal conglomerate of Pliocene in Tyosi City, Kanto Region. ln 1955, Katsumi Hirayama reported the occurrence of Perotrochus sp. from the Miocene Kobana" Formation of Kutsukake, Iono-mu 悶, Tochigi Prefecture, Northeastern Japan. In 1958, Ozaki described Perotrochus aosimai Ozaki (or Mikadotrochus aosimai (Ozaki)) from the Pliocene Na-arai Formation of Cape lnuwaka, Tyosi City. In 1961 Saburo Kanno reported the occurrence of Perotrochus otoensis Kanno from the Miocene basal Kobana Formation, at Oto, lono-mu 悶, Tochigi Prefecture. In 1973, Yasumitsu Kanie reported Entemnotrochus shikamai Kanie from the Miocene Senhata conglomerate member of the Miura Group, from Nokogiri-yama, Boso Peninsula, Central Japan. In 1967, Masae Omori figured two 'Perotrochus" from Neogene formation of Shishihara tunnel, Chiba Prefecture and Abuzuri, Kanagawa Prefecture, but without their description. In 1973, Tokio Shikama described Perotrochus (?) aoshimai Ozaki (or Mi 如 dotrochus aosimai (Ozaki)) and MikadotrochuηJ osiwarai (Oz 法 i) (or Perotrochus yoshiwarai (Ozaki)) from the basal part of the Pliocene Zushi Formation at the Sakurayama Loc. 3, Miura Peninsul DESCRIPTION OF SPECIES Order Archaeogastropoda Thiele, 1925 Suborder Pleurotomariina Cox and Knight, 1960 Superfarni1y Pleurotomariacea Swainson, 1840

3 Miocene PleurotomafÜdae from Taiwan '23 Family Pleurotomarüdae Swainson, 1840 Genus Mikadotrochus Lindholm, 1927 Mi. 如 dotrochus nantouen 月的 Lin, n. sp. Holotype: Pl. 1, la-d;pl. m la-d. Paratype: Pl. {, 2a-b ;PL m 2a-b. Shell trochiform, moderate in size, broader than high, with apica1 angle about 8 前, m 位 imum diameter of holotype 105 mm, height 78 mm, shell thick, but most part dissolved, with six or seven whorls, but only fpur whorls of holotype and less than three adult whorls of paratype are preserved, whorl subglobu1ar or somewhat obtuse1y angular, separated by well defmed sutures, with narrow shoulder at thetop; height of whorl is 34 mm near the aperture; 1ast whorl blunt1y angular at the periphery of base; base genera11y f1at, but weakly globulate, surface of base smooth; aperture subquadratic in outline with sm a11 operculum; operculum round, with concentric striae, about 17 mm in diameter, preserved in holotype specimen; base narrow1y phanelompha1us (distinctly preserved in paratype specimen), with stout co1umellar 缸 is of unknown shape; 1abra1 siit invisib1e, but may be short, because there is no visib1e trace of slit on whorl where the operculum is preserved; se1enizone at above mid-whorl, moderately broad, about 4 mm in width on its last whorl, lower and upper margins of the selenizone weakly project; lower margin of selenizone at last whorl at about 12 mm above the lower margin of the whorl, and upper margin of selenizone at about 7 mm below suture 1ine; surface ornamented by smooth revolving fme striations of less than one mm in width. Deposito Y) 人. Both holotype and paratype in Pan's collection. Locality and Formation: Both specimens obtained from the middle (?) Miocene Nankang Formation at upstream of the Takeng Va11ey, Chungliaohsiang, Nantou Prefecture, Taiwan. Comparison: The speci 剖 characteristics of genus Mi 如 dotrochus ue: 1) Shell trochiform, rather large and heavy; 2) narrowly phanerorr 叭 a1 us, with ve 可 thick and stout sigmoida1 collumbella, and a notch of moderate length; 3) whorls feebly convex, last one rounded or subangular at periphery of base; 4) labra1 slit broad, extending around 0.12 of last whorl or less, its upper margin produced beyond lower margin and merging into strongly procline, convex labrum; 5) selenizone broad, flush, spira11y grooved, below mid-whorl, slit band much inferiorly on the whorl; 6) ornament obscurly nodose spira1 cords. Although the preservation of the shell is inperfect, the present two fossils may be refered to Mi

4 24 C. C. Lin shou1der po 此 ion under the suture line; and 3) the base is smooth (yabei has numerous elevated ridges as well as radial threads). M. nantouensisis also different from M. aosimai (Ozaki, 1958), because aosimai has a broader apical angle (about ), near1y straight outer margin of whorls, more indistinct suture line, narrower selenizone (about 1 mrn), which is below the mid-whorl. The new species 也 o resembles Japanese Miocene Mikadotrochus otoensis (Kanno, 1961 吋 ), bu 叫 I 此 t di 証 ffers 台 f rom ot, 的 oens 叫呱圳 si, 必糾 s 叫 i 閃 m 函 0.743, otoensis is 0.721), 2) selenizone on otoensis is at mid-whorl; 3) lower margin of selenizone in otoensis is obtusely keeled; 4) basal disc of otoensis slightly swollen with 40 spiral threads separated with interspaces broader than width of spir 叫 threads; 5) otoensis has false umbilicus and weakly sigmoidal columel1ar axis nantouensis also resembles J apanese living Mikadotrochus beyrichi (di1gendorf, 1877), but position of selenizone and surface ornamentation are quite different. Genus Entemnotrochus P. Fischer, 1885 Entemnotrochus panchangwui Lin n. sp. Pl. 11, 3a-d; Pl.lV, 3a-d. Shell trochiform, rather large, spire hi 嶼, 月 100 mm, Dn 89 mrn, height 105 mrn, thin, 蝴 er thumade=i 器 = 1.050), wit 川 ical 呵 e 枷 ut 70 0, n d 也 is 鈴 ti 恤 ncωt, with narrow shoulder; whorl obtusely angular, lower half nearly vertica1; base weakly globulate, with curved growth striations; umbilicus large and deep, perforated, maximum diameter about 25 mm; slit long, 112 mm in length (ratio is.0.640); selenizone at about mid-whorl, (lower part about 22 mrn, upper part about 15 mm at last whorl), very narrow (about one mm in width), upper and lower margins of selenizone we 也 ly project; lower margin of apertural portion broken off; surface nearly smooth for its ill-preservatìon of shel1, but partly preserved fine spiral striations and near1y vertical growth striae. Depository: Holotype preserved in Pan's Collection. Locality and Formation: The single specimen obtained from the middle (ηmiocene Nankang Formation at upstream of the Takeng Valley, Chungliaohsiang, Nantou Prefecture, T 剖 wan. Comparison: E. panchangwui is closely related to the living species of E. rumphii (Schepm 血, 1879), which were found abundantly from the northwestern sea off Taiwan island during the past several years, but is distinguishable from the latter species by having: 1) fewer whorls, 2) hi 拉 er spire, 玲也 orter slit and 叫 ofs 叩 pi 仕 re 吼, 6 仿 ) narrower umbillicus, etc. E. panchangwui is also different from the recent species of E. adansonianus (Cross and Fischer, genotype) in 1) form of spire, 2) position and breadth of selenizone, 3) size of umbilicus, 4) form and ornament of base, etc.

5 Miocene Pleurotomariidae from Taiwan 25 2) sm 叫 l This new speωs IS 的 o different from Miocene E. shikamai Kanie in 1) outline of s 叩 pi 加昀吭, i 筒 i 若 j 技 i=0946), 4) 組 orter lab 叫 slit (the latter species with slit le 叫 I whor 吋 1). Entemnotrochus siuyingae Lin n. sp. Pl. 11, 4a-d; Pl. lv, 4a-c. Shell turbiniform, small, thin, maximum diameter of the whorl 75 mm, rninimum diameter 55 mm, height about 57 mm, apical angle about 80 v ; suture indistin 仗, surface margin of whorl nearly flat; base weakly globulate, with curved growth lines, periphery bluntly angled; umbilicus distinct and round, maximum diameter about 10 mm; slit invisible; selenzone narrow, less than one mm in width; position of selenizone below mid-wh 叫諧的 last and penultimate w 咐咖 h 切 orls, but nearly at rnid-whorl in younger stage; apertural portion broken; shell surface ornamented by many, fine, revolving, spiral threads (nine below and six above selenizone on the penultimate whorl), and crossed by fine growth lines which are somewhat oblique above and vertical below the selenizone, forrning regularly arranged, fme, beaded surface; interspaces of the revolving threads are narrow and shallow. Depository: Holotype preserved in Pan's Collection. Localiσ and Formation: Obtained from the Middle (?) Miocene Nankang Formation at upstream of the Takeng Valley, Chungliaohsiang, Nautou Prefecture, Taiwan. Compa/ 吻 on: This species is quite different from other living and fossil Entemnotrochus in its smaller size and position of selenizone. LITERATUkE CITED Abbott. R. T., 1974; American Seashells; pp Cox L. R., Brookes Knight, et al., 1960; Systematic Descriptions of Gastropoda in Treatise on Invertebrate Paleontology" directed and edited by Raymond C. Moore (1) Mollusca 1, , (Suborder Pleurotomariina, Superfarni1y Pleurotomariacea, Family Pleurotomariidae ). 1955; Discovery of Perotrochus in the Miocene deposits of Tochigi Prefecture, HirayamaφK., Kanno. Japan; Venus XVIII, Kanie, Yasumitsu, 1973; A new species of Miocene Entelηnotrochus from the south Nokogiriyama, Boso Peninsula, Japan; Sci. Rep. Yokosuka City Museum, no. 20, S., 1961, Miocene 'Pleurotomaria" and its associated fauna from 10chigi Prefecture, Japan; Jap. J. Geol. Geogr., No. 32, Kuroda, T.1955; A New Pleurotomaria from Japan, with a note on a specimen of P. rumphii Schepman collected from Taiwan; Venus XVIlI,

6 26 C. C. Lin Nomura, S. and Nüno, H. 1932; Fossil mollusca from lzu and Hakone; Sci. Rep. Tohoku Imp. U, 帥, 2nd. Ser. B (Geology) XV, 大森昌 1 括 : 1967; 中部鬥本第三紀後期泣如付石 "pleurotomaria" 海逃犯 "'":)\, τ; 終因秀質教授 退官司念論文麓, Oz 也 i, H. 1954; On the Paleontology of the basa1 conglomerate ofpliocene in Tyosi City, Kanto region;bull. Nat. Sci. Mus., N. S.I, no.l, Ozaki, H. 1958; Stratigraphica1 and pa1eontologica1 studies on the Neogene and Pleistocene Formation of the Tyosi district; Bull. Nat. Sci. Museum (Tokyo), no.42: Sikarr 嗨 T. 1973; Molluscan assemblages of the basa1 pa-rt of the Zushi Formation in the Miura Peninsula;Tohoku Univ. Sci. Rep., ser. B (Geol.) Special Volume, no. 6: 臺灣省南投縣立中新世翁或螺科化石 林手月品已 國立臺灣大學地質學系 摘要 世界有名之活化右 翁吾先螺 J, 在新生代地層及現海中甚為稀罕 堂閉近海為世界現生翁或螺之 五個重要產地之一 其他四處 f.;í 日本, 西印度 印尼及南非 空崗近海出產現生十五種中之四種, 自 IJ 龍宮翁我螺 寺阿氏章主主立蛾 ; 高腰翁我螺及籽, 色畫畫我螺 遠東之新生代翁我螺化石, 也被採到十種, 均產於日本之第三紀始新 iij: 中新世及上新世地層中 o 台新世一種, 中新世及上新世九種 本文再添 加三種南投縣所產之中國第三紀翁我螺化石, 使遠東之新生代翁吾先螺連至十三種之多 此三新種翁我螺化石乃 南投翁我螺 J ( 悶版 1 即 ) 潛常武翁我螺 J ( 圖版 IL 3a 吋 IV, 3a-d ) 及 秀英 翁我螺 J ( 圖版 IL 但 -d ; IV, 4a-c ) 筆者在本文中詳細記載此三種畫灣中新世翁我螺化石之特徵及 其與各近似種之比較, 同時以照相 ; 及繪圖表示其形像 著者借此機會, 對採取者諸常武先生 秀英女士夫婦表示敬范 ; 與謝意 本研究乃行政院國家科學琴只會主按之 華商濁水 大肚兩溪流域自然與文化史科際研究計刮 中地質組業績之一部份, 對該委員會之經費支援亦深表謝忱 著者同時對提供文獻之日本古生物學者尾時傳 大森昌衛 早圾祥三 藤山家德等諸位博士敬表謝意

7 Miocene P leurotomariidae from Taiwan 27 EXPLANATION OF PLATES Pl. 1 la, b, c, d: Mìkadotrochus nantoensis Lin, n. sp, holotype la: Apertural view (with operculum); (xo.8) 1 b: Side view; (xo.67) 1 c: Apical view; (xo.58) 1 d: Basal view; (xo.5y) 泊, b: Mìkadotrochus nantouensis Lin, n. sp., paratype. 2a: Apertural view; 但 0.68) 2b: Basal view; (xo.63) Pl. 11 3a, b, c, d: Entemnotrochus panchangwuì Lin, n. sp. 3a: Apertural view; (xo.61) 3b: Side view; 如 0.76) 3c: Apical view; (xo.74) 3d: Basal view; (xo.62) 4a, b, c, d: Entemnotrochus sìuyingae Lin, n. sp. 4a: Apertural view; 但 0.74) 4b: Side view; (xo.71) 4c: Apical view; 如 0.90) 4d: Basal view; (xo.77) Pl. III 1 a, b: Mikadotrochus nantouensis Lin, n. sp. holotype 1 a: Apertural view; s: preserved selenizone fragment 1 b: Side view; lc, d: Mikadotrochus nantouensislin, n. sp. holotype Pl. IV 3a, b: Entemnotrochus panchangwui Lin, n. sp. holotype 3a: Apertural view; 3b: Side view; 3c, d: Entemnotrochus panchangwui Lin, n. sp. holotype 3c: Apical view; 3d: Basal view; 4a, b, c: Entemnotrochus siuyingae Lin, n. sp. holotype 4a: Apertura! view; 4b: Apica1 view; 4c: Basal view;

8 .28 c. C. Lin 10 1d A可EE-hU

9 M;ocene Pleurotomariidae from Taiwan 29 一一一一一 30

10 30 C. C. Lin PI. III 1c CM

11 Miocene Poeurotomariidae from Taiwan 31 PI. N