Bull. Kitakyushu Mus. Nat. Hist., 2: 25-31. March 25, 1980

Early Cretaceous Freshwater Fishesfrom Northern Kyushu, Japan

II. Restoration of Two Species of the ClupeoidFish genus Diplomystus

Teruya Uyeno

National Science Museum, Tokyo 160 Japan

and

Yoshitaka YABUMOTO

The Office of Preparation for Kitakyushu Museum of Natural History,Tobata Shiminkaikan Bldg., 1-49, Senbo 1-chome, Tobataku,

Kitakyushu City, 804, Japan

In the previousr eport (Uyeno, 1979), two primitive species of the genusDiplomystus, D. primotinus and D. kokuraensis, were described on the basis of anumber of fossil remains found from a freshwater bed of Neocomian age, inKitakyushu city in the northern part of Kyushu Island, Japan.

Here we tried to reconstruct their osteological structure from fragmentalinformations obtained from fossil specimens, and osteological observations onRecent specimens of Hyperlophus vittatus from Australia, which has been consideredas the closest relative of Diplomystus, among Recent double armoured herring(SCHAEFFER, 1974).

Material and method

All of the fossil material were collected at the locality 130°5r46wE, 33°51'11"N, Kumagaya 4-chome, Kokura-kita-ku, Kitakyushu City, Fukuoka Prefecture, Japan.

The horizon is Neocomian, Early Cretaceous. The upper layer (fourthlayer) of the Wakino-subgroup, Kanmon-group. Information in detail arepresented elsewhere (Ota and others, 1978; 1979; Uyeno, 1979).

In order to draw figures of the restoration, important parts were drawnfirst from many fragments, using Wild dissecting microscope with a drawingdevice. Then drawings of the holotypes were made for each species. Finallycomposite figures were constructed on the basis of information gathered from allmaterial.

26 Teruya Uyeno and Yoshitaka Yabumoto

EPi—3

Figure 1. The caudal skeleton of Diplomystus kokuraensis, KMNH VP 100,071.

CSC, caudal scute; EP, epural; H, hypural; HP, parhypural;PU, preural centrum; U, ural centrum; and UN, uroneural bone.

Recent specimens of Hyperlophus vittatus was cleared and stained with 2%KOH and arizarine red S.

Remarks

We have obtained only few specimens of an entire body of these two species.The preservation of the fossils are not necessarily good, but certain individualbones are clearly observable in fragments which are shown in photographs(Pis. 3-4).

In addition to the characters in the original description (Uyeno, 1979), welooked for the parasphenoid teeth in these two species. Though specimens areso small to observe fine structures, we think we found impression of very smalltooth-like structure in front of the posterior end of the parasphenoid, in the typespecimens of both species. It is unfortunate that we are not able to state thatthe presence of the parasphenoid teeth with confidence. We did not find theparasphenoid teeth in specimens of Recent Hyperlophus vittatus.

Concerning the number of the dorsal scutes ofD. kokuraensis, 8 was the maximum observable number previously, but we found a fragment with 12 scutes,which was recently collected by Mr. Matano.

Acknowledgments

We would like to express our appreciation to Dr. Masamichi Ota of the

Restoration of Diplomystus 27

Kitakyushu Museum of Natural History for his kind arrangements to study thematerial. Mr. Takashi Sotsuka of Kokura Senior Highschool and Mr. FumiakiMatano who collected fossil specimens at the locality provided us fragments withmany important features of two species of Diplomystus.

Literature Cited

Ota, M., Toriyama, R., Hojo, Y., Sotsuka, T., Nishida, T., Sugimura, A., Haikawa, T.,Nagai, K. and Suoiyama, T., 1978. Geology: 3-12, figs. 1-8. in The report of the secondexcavation for the Cretaceous fish fossils in Kokura, Kitakyushu City, Japan. KitakyushuKyoiku Iinkai, 42 pp., 12 figs., 16 pis. (in Japanese).

Ota, M., Toriyama, R., Hojo, Y., Sotsuka, T., Nishida, T., Fujii, A., Sugimura, A., Haikawa,T., Nagai, K. and Sugiyama, T., 1979. Geology of the Kanmon Group in the southerndistrict of Kitakyushu City. Bull. Kitakyushu Mus. Nat. Hist., (1): 1-10, figs. 1-6, pis. 1-2(in Japanese).

Schaeffer, B., 1974. Cretaceous and Tertiary Actinopterygian fishes from Brazil. Bull. Amer.Mus. Nat. Hist., 89: 1-39, figs. 1-6, pis. 1-7.

Uyeno, T., 1979. Early Cretaceous freshwater fishes from northern Kyushu, Japan. I. Description of two new species of the clupeid genus Diplomystus. Bull. Kitakyushu Mus. Nat. Hist.,(1): 11-24, figs. 1-3, pb. 3-4, tab. 1.

Fig

ure

2.D

iplo

mys

tus

prim

otin

us,

holo

type

,K

MN

HV

R10

0,00

1.Sc

ale

indi

cate

10m

m.

Restoration of Diplomystus 29

-:

Figu

re4.

Rec

onst

ruct

ion

ol"

Dip

lom

ystu

spr

imot

inus

.

Restoration of Diplomystus 31

tf

Teruya Uyeno and Yoshitaka Yabumoto

Early Cretaceous Freshwater Fishes From NorthernKyushu, Japan

II. Restoration of Two Species of the ClupeoidFish genus Diplomystus

Plates 3-4

Explanation of Plate 3

Diplomystus primotinusFig. 1. preopercle, KMNH VP 100, 005. (x8.5)

2. shoulder girdle, KMNH VP 100, 005. (x 8.5)3. quadrate, KMNH VP 100, 005. (X 8.5)4. dentary, KMNH VP 100, 072. (X 7.9)5. predorsal scutes, KMNH VP 100, 010. (x 4.2)6. dorsal fin, KMNH VP 100, 010. (x 4.2)7. anal fin, KMNH VP 100, 004. (X 4.1)8. caudal region, KMNH VP 100, 073. (X 11.7)

Uyeno, T. and Y. Yabumoto: Restoration of Diplomystus Plate 3

i

Plate 4

rt

Explanation of Plate 4

Diplomystus kokuraensisFig. 1. head region, KMNH VP 100, 034. (x 3.4)

2. caudal region, KMNH VP 100, 035. (x 9.7)3. predorsal scutes, KMNH VP 100, 040. (X 7.4)4. dorsal fin, KMNH VP 100, 031. ( X5.2)5. predorsal scutes, KMNH VP 100, 039. (x 7.5)6. anal fin, KMNH VP 100, 039. (x5.5)

Uyeno, T. and Y. Yabumoto: Restoration of Diplomystus Plate 4

jtj* .<

:^,i;:/

r/miV-AbKM (Mlrf. * hbw* •£, •:.. & . s vml:*.