豊田ホタルの里ミュージアム研究報告書 第 14 号 : 69-72 頁 , 2022 年 3 月
Bull. Firefly Museum of Toyota Town. (14): 69-72, Mar. 2022

A record of the discovery of Japan’s oldest turtleTadashi FUJINAGAToyourachō Ōaza Kawatana, Shimonoseki, Yamaguchi, Japan

Translated by Benjamin T. BREEDEN III
Department of Geology & Geophysics, University of Utah, 115 S 1460 E, Salt Lake City, Utah 84112, USA, b.breeden@utah.edu

Abstract: This is an English translation of an article by Tadashi Fujinaga entitled ‘｢ 日本最古のカメ」発見記 ’ (romanized ‘｢Nihon saiko no kame｣ hakken ki’), which was originallypublished in Japanese in 1990 within issue 10 of カルスト (Karusuto), a publication of theMine Natural History Association ( 美祢自然史友の会 Mine Shizenshi Tomo no Kai) andthe Mine City Museum of History and Folklore ( 美祢市歴史民俗資料館 Mine-shi Rekishi
Minzoku Shiryōkan). The article is reproduced in translation with permission from the Mine
Natural History Association. The original figures have been modified and augmented withadditional photographs.
Key words: Early Jurassic, Nishinakayama Formation, Testudinata, Toarcian, Toyora Group,
vertebrate paleontology“It’s a turtle!”
With that exclamation voiced by the curator Mr. Takahashia, my hobby of collecting fossils moved one large step forward.
On the second day of the New Year in 1989, three years since I had started collecting fossils, I was returning home toShimonoseki from visiting my parents in Mitōchō Manab when I made a carefree stop in Toyotachō at 4:30 in the evening.
My starting point of collecting fossils was here in Toyotachō Ishimachi (Figure 1A). I had already visited ten-odd times
before, and each visit had produced specimens of familiar ammonites such as Dactylioceras and Protogrammoceras. At first,
it had been exciting to find just fragments of fossils, but I kept coming back craving bigger and more beautiful specimens.
The river Eragawa flows from the mountain Gesan over the Nishinakayama Formation, the middle unit of the Toyora Group,
eroding the bedrock into rolling stones of black shale that are very easy to collect. Collecting fossils from these stones in theriver rather than hammering away at subaerial outcrops causes very little destruction of nature or feelings of guilt for intrudingon another person’s land. I was unsuccessful collecting beneath the bridge Ishimachibashi on Yamaguchi Prefectural Road
No. 34 (Figure 1A), and it was past 5:00 in the eveningc, so I returned to the confluence with the main river Koyagawa to try
my luck there before heading home (Figure 1B). I used my hammer to split one of the cobbles of shale that are common in theriverbed and immediately saw a nearly 10-centimeter specimen of the ammonite Protogrammocerasd. The weathered slabsof the cobble were broken apart; however, I collected the many fragments of the precious fruits of my labor, satisfied with theday’s results.
This led to good fortune. The next day, I glued the fragments together to repair the slabs. Luckily, there was another fossil
next to the ammonite that piqued my curiosity. At first glance, I thought it looked like the round fruit of a plant. Hoping for ahint, I showed it to my wife, but she gave only a slight reaction and didn’t think it was a big deal. Therefore, two months later, I69

Tadashi FUJINAGA

asked Mr. Takahashi to appraise the specimen when I had the opportunity at an inspection tour on 19 March 1989.
Three days later, the discovery in Ishikawa Prefecture of Japan’s oldest Cretaceous turtlee was reported by the news ontelevision; however, I was confident that my specimen was older, so after that, I sent it to be appraised by Professor Hasegawaf
at Yokohama National University, who said the fossil was “Japan’s oldest baby soft-shelled turtle.”g
I am profoundly grateful to all my seniors for their aid in producing these results, which are like a dream to me. AlthoughI sent my ‘child’ eastward to Yokohama for appraisal, I pray that even half of the specimen returns to its hometown in Minesoon.hA

BEragawa

Toward華Gesan山

Narusebashi
鳴瀬橋

江良
川
Ishimachibashi

Prefectural Road No.

県道 34号34

石町橋
石町Ishimachi

N

Provenanceof turtle fossil
MMHF 5-00001

B
木屋川

FLOW

C

Narusebashi
Koyagawa

D

鳴瀬橋

E

10 mm

Figure 1. (A) Map of Toyotachō Ishimachi, Shimonoseki, Yamaguchi, Japan showing the locality fromwhich the turtle fossil MMHF 5-00001 was collected on 2 January 1989. Modified from Fujinaga (1990).
(B) Tadashi Fujinaga standing at the point where he discovered the turtle fossil MMHF 5-00001 ex situ
in Eragawa immediately upstream from its confluence with Koyagawa. Photograph taken on 3 August
2019 by the translator. (C) Tadashi Fujinaga holding the turtle fossil MMHF 5-00001 at Kaigetsu Ryokan
in Toyotachō Ōaza Tonoshiki, Shimonoseki, Yamaguchi, Japan. Photograph taken on 3 August 2019by the translator. (D) The turtle fossil MMHF 5-00001. (E) Cover to issue 10 of カルスト (Karusuto)
from March 1990, which contained the original Japanese article by Tadashi Fujinaga. This issue marked
the 10th anniversary of the bulletin. Reproduced with permission from the Mine Natural History Association.

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A record of the discovery of Japan’s oldest turtle

Translator Notes
aFumio Takahashi remains the curator of the Mine City Museum of History and Folklore as of February 2022.

bA town in eastern Mine, Yamaguchi, Japan.

cThe sunset in Toyotachō on that day was at 17:18.

dThis ammonoid specimen was later referred to “Harpoceras (s.s.) chrysanthemum” (=Cleviceras chrysanthemum) byHasegawa et al. (1998).
eFrom the Lower Cretaceous Tetori Group in Shiraminemura, which was merged with other local towns and villages to form

the city Hakusan in 2005. Hundreds of Early Cretaceous turtle fossils have been collected from the Tetori Group in this region(e.g., Hirayama, 2000).
fYoshikazu Hasegawa retired from Yokohama National University in 1995 and took a position at the Gunma Museum ofNatural History.
g

Subsequent articles by Hasegawa et al. (1998) and Breeden and Izumi (2019) referred the specimen to the decreasinglyexclusive clades of Testudines and Testudinata, respectively. A more detailed study of the specimen’s phylogeny and taxonomy
is in progress, but it is clear that the specimen is not a trionychid (i.e., a soft-shelled turtle).
hThe material was ultimately returned from Yokohama. Both slabs of the turtle fossil are now reposited at the Mine City

Museum of History and Folklore and were assigned the specimen number MMHF 5-00001. (Figure 1C–D)
ACKNOWLEDGMENTS
This article was translated as part of BTB’s Ph.D. dissertation research on the vertebrate fossil record of the NishinakayamaFormation in Toyotachō. This project was funded by the American Philosophical Society Lewis and Clark Fund for
Exploration and Field Research, a Geological Society of America Graduate Student Research Grant, and the University ofUtah Department of Geology and Geophysics (Cleveland-Lloyd Quarry Fund, David S. and Inga M. Chapman Fund, M.
Dane Picard Fund). BTB thanks Tadashi Fujinaga for his kindness and cooperation throughout this project, Fumio Takahashi(Mine City Museum of History and Folklore) for facilitating access to MMHF 5-00001 and providing a copy of the issueof カルスト containing the article translated here (see Figure 1E), Kenrō Hironaka (Mine Natural History Association) for
granting permission to reproduce this article in translation, Keisuke Kawano (Firefly Museum of Toyota Town) and YuriKimura (National Museum of Nature and Science) for their assistance with points of this translation, Kazuko Akieda (KaigetsuRyokan) for her hospitality in providing a comfortable space to meet with Tadashi Fujinaga in Toyotachō, Kentaro Izumi (ChibaUniversity) and Makoto Manabe and Chisako Sakata (National Museum of Nature and Science) for their collaboration andassistance with countless logistics throughout this project, and Wakako Akamine, Sae Kawase, Chisato Kojima, and Yoko
Azuma (University of Utah) for their generosity and patience as Japanese language instructors.
REFERENCES
Breeden III, B. T., Izumi, K. (2019) A review of the vertebrate fossil assemblage from the Lower Jurassic Nishinakayama
Formation in the Ischimachi district of Toyota Town, Yamaguchi Prefecture, Japan. Bulletin of the Firefly Museum ofToyota Town, 11: 9-23.
Fujinaga, T. (1990) ｢Nihon saiko no kame｣ hakken ki. Karusuto, 10: 2. [ 藤永 正 (1990) ｢ 日本最古のカメ ｣ 発見記 . カルスト , 10: 2.] (In Japanese)
Hasegawa, Y., Manabe, M., Hirano, H., Takahashi, F. (1998) A turtle from the Early Jurassic Toyora Group, Yamaguchi, Japan.

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Memoirs of the National Museum of Nature and Science, 31: 67-72.
Hirayama, R. (2000) Fossil turtles from the Kuwajima Formation (Tetori Group, Early Cretaceous) of Kuwajima Kaseki-kabe in
Shiraminemura, p. 75-92. In Matsuoka, H. (ed.), Fossils of the Kuwajima ‘‘Kaseki-kabe’’ (Fossil-bluff). Scientific Report on aNeocomian (Early Cretaceous) fossil assemblage from the Kuwajima Formation, Tetori Group, Shiramine, Ishikawa, Japan.
Shiramine Village Board of Education, Ishikawa Prefecture, Japan. [ 平山 廉 (2000) 白峰村桑島化石壁の手取層群桑島層 ( 白亜紀前期 ) より産出したカメ化石 . 石川県白峰村桑島化石壁の古生物 - 下部白亜系手取層群桑島層の化石群 -. 石川県白峰村教育委員会 , p. 75-92.] (In Japanese with English Abstract)72