Japanese theropod nomen nudum extravaganza

[Michael Mortimer <mickey_mortimer111@msn.com>]

Among the most elusive dinosaurs have been the Japanese nomina nuda we all 
remember so well from The Dinosaur Data Book and DinoGeorge's list.  I've spent 
the last few days looking into these for my website, and here I present all the 
data I've been able to gather on them, together in one place for the first time.

"Futabasaurus" Lambert, 1990
Coniacian, Late Cretaceous
Ashizawa Formation of the Futaba Group, Japan
Material- (unknown collection; Futaba-ryu) (~1.5-2 m) partial tibia (~56 mm 
wide)
Comments- This specimen was originally mentioned by Hasegawa et al. (1987) in 
an abstract as Futaba-ryu, as dinosaur remains in Japan are often given 
nicknames ending in "ryu" (= dragon). Lambert (1990) inappropriately made it 
into a genus name, listing it as "Futabasaurus" in a childrens' book. It was 
mentioned as being a large carnosaur (sensu lato) from Japan that had yet to be 
described. Dong et al. (1990) referred to it as Tyrannosauridae gen. et sp. 
indet. and published a photograph. Olshevsky (1991) listed it as an allosaurid 
without comment, and later (DML, 2001) as a probable junior synonym of 
Tarbosaurus. Chure (2000) briefly discussed and illustrated the specimen, 
excluding it from Allosauridae based on a few differences from Allosaurus 
(lateral edge less elongated ventrally; medial edge not rounded and drawn out 
medially). While these mean "Futabasaurus" is not Allosaurus itself, they do 
little to pin down its relationships further. With only a low quality photocopy 
to go
 by, I can't make any phylogenetic judgements.
A genus of elasmosaurid plesiosaur was later named Futabasaurus by Sato et al. 
(2006), making the name unavailable for the theropod tibia. 
References- Hasegawa, Watanabe, Oshida, Takizawa and Koda, 1987. Dinosaur 
Assemblage from the Futaba Group, Fukushima. Abstract of the Annual Meeting of 
the Paleontological Society of Japan. 4.
Lambert, 1990. The Dinosaur Data Book. New York: Avon Books, 66. ISBN 
0-380-75896-3. 
Dong, Hasegawa and Azuma, 1990. The Age of Dinosaurs in Japan and China. Fukui, 
Japan: Fukui Prefectural Museum. 65 pp.
Matsukawa and Obata, 1994. Dinosaurs and sedimentary environments, in the 
Japanese Cretaceous: a contribution to dinosaur facies in Asia based on 
molluscan paleontology and stratigraphy. Cretaceous Research. 15, 101-125.
Chure, 2000. A new species of Allosaurus from the Morrison Formation of 
Dinosaur National Monument (Utah-Colorado) and a revision of the theropod 
family Allosauridae. Ph.D. dissertation, Columbia University, 1-964. 
Sato, Hasegawa and Manabe, 2006. A new elasmosaurid plesiosaur from the Upper 
Cretaceous of Fukushima, Japan. Palaeontology. 49(3), 467-484.

"Kagasaurus" Hisa, 1988
Hauterivian, Early Cretaceous
Kuwajima Formation of the Itoshiro Subgroup of the Tetori Group, Japan
Material- (FPM 85050-1; Kaga-ryu) (~6 m) partial anterior tooth (>19.5 mm) 
(Manabe et al., 1989)
? tooth (Azuma, 1991)
Comments- The first tooth was discovered in 1985 and referred to Carnosauria. 
This was illustrated and described in detail by Manabe et al. (1989), who 
assigned it to Carnosauria fam. indet.. This was based on comparison to a 
supposedly carnosaurian tooth (NSMP17178-17180) from Lufeng. Between 1985 and 
1990 an additional tooth was discovered, referred to Megalosauridae indet 
(Azuma, 1991). Hisa (1988) referred to at least one of the teeth as 
"Kagasaurus", which is a nomen nudum because it wasn't associated with a 
description. Manabe et al. state FPM 85050-1 has the nickname Kaga-ryu, while 
Azuma calls both teeth Kaga-ryu. Dong et al. (1990) regard the teeth as 
Megalosauridae indet.. Whether both teeth are referrable to the same taxon is 
unknown, as the second has yet to be described.
FPM 85050-1 preserves on the the basal two-thirds of a tooth with a FABL 10.6 
mm and a basal width of 5.6 mm. The lingual face is flat and the labial one 
convex, indicating this is probably a premaxillary or anterior dentary tooth. 
The mesial carina lacks serrations, while the distal carina has 17 serrations 
per 5 mm. The serrations are rounded and angled slightly apically.
The flat lingual face is present in abelisaurids, at least some carnosaurs and 
most coelurosaurs (except those taxa which lack carinae). Abelisaurids and 
carnosaurs always have mesial serrations, often extending to the base of the 
crown. Some basal coelurosaurs and dromaeosaurids have anterior teeth which 
lack mesial serrations, making "Kagasaurus" likely to be a member of one of 
these groups. 
References- Hisa, 1988. Utan Scientific Magazine. 4(24).
Manabe, Hasegawa and Azuma, 1989. Two new dinosaur footprints from the Early 
Cretaceous Tetori Group of Japan. Gillette and Lockley (eds.). Dinosaur Tracks 
and Traces. Cambridge University Press, Cambridge. 309-312. 
Dong, Hasegawa and Azuma, 1990. The Age of Dinosaurs in Japan and China. Fukui, 
Japan: Fukui Prefectural Museum. 65 pp. 
Azuma, 1991. Early Cretaceous Dinosaur Fauna from the Tetori Group, central 
Japan. Research on Dinosaurs from the Tetori Group (1). Professor S. Miura 
Memorial Volume, 55-69.

"Katsuyamasaurus" Lambert, 1990
Barremian, Early Cretaceous
Kitadani Formation of the Akaiwa Subgroup of the Tetori Group, Japan
Material- (unknown collection; Katsuyama-ryu) (~4 m) (?) mid caudal vertebra 
(68 mm), ulna (~200 mm)
Comments- This material was informally called "Katsuyama-ryu", as found in 
Azuma (1991). Lambert (1990) inappropriately made it into a genus name, listing 
it as "Katsuyamasaurus" in a childrens' book. Dong et al. (1990) published 
photos of the remains, labeling them Allosauridae indet.. They were later 
described by Chure (2000), who suggested the caudal may derive from an 
ornithopod. He noted it lacks lateral pleurofossae and was reminiscent of 
iguanodonts, which are known from the same quarry (Fukuisaurus, described by 
Kobayashi and Azuma, 2003). Olshevsky (DML, 2000) considered "Katsuyamasaurus" 
a likely junior synonym of Fukuiraptor, which was discovered later in the same 
quarry. However, the ulna differs from Fukuiraptor in being straight 
proximally, with a larger olecranon process and a more prominent and proximally 
prjecting anteroproximal process. The large olecranon process excludes it from 
Maniraptoriformes, but more precise affinities within Theropoda are unknown at 
this
 time.
References- Dong, Hasegawa and Azuma, 1990. The Age of Dinosaurs in Japan and 
China. Fukui, Japan: Fukui Prefectural Museum. 65 pp. 
Lambert, 1990. The Dinosaur Data Book. New York: Avon Books, 66. ISBN 
0-380-75896-3. 
Azuma, 1991. Early Cretaceous Dinosaur Fauna from the Tetori Group, central 
Japan. Research on Dinosaurs from the Tetori Group (1). Professor S. Miura 
Memorial Volume, 55-69.
Chure, 2000. A new species of Allosaurus from the Morrison Formation of 
Dinosaur National Monument (Utah-Colorado) and a revision of the theropod 
family Allosauridae. Ph.D. dissertation, Columbia University, 1-964. 
Olshevsky, DML 2000. http://dml.cmnh.org/2000Dec/msg00399.html
Kobayashi and Azuma, 2003. A new iguanodontian (Dinosauria: Ornithopoda) from 
the Lower Cretaceous Kitadani Formation of Fukui Perfecture, Japan. Journal of 
Vertebrate Paleontology. 23(1), 166-175.

"Kitadanisaurus" Lambert, 1990
Barremian, Early Cretaceous
Kitadani Formation of the Akaiwa Subgroup of the Tetori Group, Japan
Material- (Kitadani-ryu) tooth (Dong et al., 1990)
?(FPDM-V96082619) dorsal vertebra (Azuma and Currie, 2000)
?(FPDM-V9812638, 96072901, 97082906, 980815181, 98092604) five teeth (Azuma and 
Currie, 2000)
?(FPDM-V98081115) humerus (144 mm) (Currie and Azuma, 2006)
?(FPDM-V980801141) manual ungual (Currie and Azuma, 2006)
? several unguals (Currie and Azuma, 2006)
Comments- The original tooth was informally called "Kitadani-ryu", as found in 
Azuma (1991). Lambert (1990) inappropriately made it into a genus name, listing 
it as "Kitadanisaurus" in a childrens' book. Dong et al. (1990) published 
photos of the tooth, labeling it Dromaeosauridae indet.. In 1991, jaw fragments 
were found in the quarry and identified as dromaeosaurid based on their fused 
interdental plates. This was followed by the discovery of a manual ungual I, 
astragalus and metatarsal III in 1993. Azuma and Currie (1995) described these 
remains in an abstract as those of a giant dromaeosaurid, which was associated 
in the paleontological community with "Kitadanisaurus" through the late 1990's. 
Azuma and Currie (2000) later described the skeletal remains as a new taxon of 
carnosaur, Fukuiraptor. Yet they also noted smaller teeth are known, similar in 
size and shape to dromaeosaurids and sharing Dromaeosaurus' mesial carina 
twist, as well as a dorsal vertebra "suggestive of
 dromaeosaurid affinities." Currie and Azuma (2006) list the teeth which are 
not referrable to Fukuiraptor, and describe and illustrate a humerus they refer 
to Dromaeosauridae indet.. In addition, they state several unguals seem to be 
dromaeosaurid, though these remain undescribed. One manual ungual is listed as 
having a proximodorsal lip, which is present in most dromaeosaurids as well as 
some other coelurosaurs. It is probably one of the several, though the only 
other listed ungual is a distal tip (FPDM-V9912141). Even if these remains are 
all dromaeosaurid, they do not necessarily belong to the same taxon. 
"Kitadanisaurus" remains a nomen nudum, as the original tooth has never been 
described.
References- Dong, Hasegawa and Azuma, 1990. The Age of Dinosaurs in Japan and 
China. Fukui, Japan: Fukui Prefectural Museum. 65 pp. 
Lambert, 1990. The Dinosaur Data Book. New York: Avon Books, 66. ISBN 
0-380-75896-3. 
Azuma, 1991. Early Cretaceous Dinosaur Fauna from the Tetori Group, central 
Japan. Research on Dinosaurs from the Tetori Group (1). Professor S. Miura 
Memorial Volume, 55-69.
Azuma and Currie, 1995. A new giant dromaeosaurid from Japan. Journal of 
Vertebrate Paleontology. 15(3), 17A. 
Azuma and Currie, 2000. A new carnosaur (Dinosauria: Theropoda) from the Lower 
Cretaceous of Japan. Canadian Journal of Earth Sciences. 37(12), 1735-1753.
Currie and Azuma, 2006. New specimens, including a growth series of Fukuiraptor 
(Dinosauria, Theropoda) from the Lower Cretaceous Kitadani Quarry of Japan. J. 
Paleont. Soc. Korea. 22(1), 173-193. 

"Mifunesaurus" Hisa, 1985
Middle Cenomanian, Late Cretaceous
Kabu Formation of the Mifune Group, Japan
Material- (YNUGI 10003; Mifune-ryu) (~6-7 m) maxillary tooth (72.7 mm)
Comments- This tooth was discovered in 1979, and described in 1984 by Hawegawa 
and Murata. They referred it to Megalosauridae gen. et. sp. indet., and 
nicknamed it Mifune-ryu. Hisa (1985) later gave it the nomen nudum 
"Mifunesaurus" in an illustrated booklet on dinosaurs. It was illustrated and 
described in detail by Hasegawa et al. (1992), who referred it to 
Megalosauridae based on similarity to "Walkersaurus", Gasosaurus and a Chinese 
specimen of unknown stratigraphic origin probably incorrectly referred to 
Megalosaurus bucklandii. They thought it was distinct from other named 
theropods in its low basal width to crown length ratio (.17), but this is also 
seen in ceratosaurids, for instance. It remains a nomen nudum because Hawegawa 
et al. did not name the tooth, while Hisa's (1985) description was apparently 
deficient. While Chure (2000) stated some of the teeth from the Kabu Formation 
have enamel wrinkles, Chure et al. (1999) show he was referring to a tooth from 
the Jobu
 Formation (MDM 341). Additional remains from the Jobu Formation of the Mifune 
Group (Tamara et al., 1991- four teeth, tibia, fibula, metatarsals II and III) 
are sometimes referred to "Mifunesaurus" as well, but although Chure (2000) 
stated the teeth were similar, there are no reported synapomorphies which would 
allow placing them in the same taxon.
The tooth crown is 72.7 mm tall, with a FABL of 22.5 mm and a basal width of 
12.3 mm. It is recurved and lens shaped in section, with almost symmetrically 
distributed carinae. There are 20 serrations per 5 mm on both mesial and distal 
carinae. Blood grooves are present at least posteriorly, but enamel ridges are 
absent. "Mifunesaurus"' tooth seems too thick to be a ceratosaurid, and taller 
than in abelisaurids, so is probably from a non-maniraptoriform tetanurine, 
such as a spinosauroid or carnosaur.
References- Hasegawa and Murata, 1984. First Record of Carnivorous Dinosaur 
from the Upper Cretaceous of Kyushu, Japan. Abstract of the Annual Meeting of 
the Paleontological Society of Japan.
Hisa, 1985. 
Dong, Hasegawa and Azuma, 1990. The Age of Dinosaurs in Japan and China. Fukui, 
Japan: Fukui Prefectural Museum. 65 pp. 
Tamara, Okazaki and Ikegami, 1991. Occurence of carnosaurian and herbivorous 
dinosaurs from upper formation of Mifune Group, Japan, Memiors of the Faculty 
of Education, Kumamoto University. 40, 31-45.
Hasegawa, Murata, Wasada and Manabe, 1992. The first carnosaur (Saurischia; 
Theropoda) from Japan; A tooth from the Cenomanian Mifune Group of Kyushu. Sci. 
Rep. Yokohama Natl. Univ. Ser. 2 39, 41-49.
Chure, Manabe, Tanimoto and Tomida, 1999. An unusual theropod tooth from the 
Mifune Group (Late Cenomanian to Early Turonian), Kumamoto, Japan. in Tomida, 
Rich, and Vickers-Rich (eds.). Proceedings of the Second Gondwanan Dinosaur 
Symposium. National Science Museum (Tokyo) Monographs. 15, 291-296. 
Chure, 2000. A new species of Allosaurus from the Morrison Formation of 
Dinosaur National Monument (Utah-Colorado) and a revision of the theropod 
family Allosauridae. Ph.D. dissertation, Columbia University, 1-964. 

"Sanchusaurus" Hisa, 1985
Late Barremian-Aptian, Early Cretaceous
Lower Sebayashi Formation, Japan
Material- (GMNH-PV-028; Sanchu-ryu) (~7 m) first or second sacral centrum (110 
mm)
Comments- This specimen was discovered in 1981 and 1982, and reported as a 
caudal centrum nearly identical to Gallimimus by Hasegawa et al. (1984). They 
nicknamed the specimen Sanchu-ryu, which was inappropriately made into the 
nomen nudum "Sanchusaurus" by Hisa (1985) in an illustrated Japanese booklet. 
Hasegawa et al. (1999) later described the centrum in detail as a thirteenth 
dorsal vertebra, based on comparison to Gallimimus. Yet the thirteenth dorsal 
vertebra as identified by Osmolska et al. (1987) is recognized as the first 
sacral vertebra by most modern workers, making "Sanchusaurus"' vertebra a 
sacral instead. The lateral fossae indicate this is an ornithomimosaur, as only 
they and Avimimus are known to have the feature among non-avian theropods. 
Avimimus differs in having either convex or concave ventral surfaces on its 
anterior sacrals (Makovicky, 1995). Though stated by Hasegawa et al. (1984, 
1999) as being nearly identical to Gallimimus' first sacral, several differences
 are apparent. The anterior width is ~107% of its height, compared with ~80% in 
Gallimimus. "Sanchusaurus"' centrum is deeply amphicoelous, while Gallimimus' 
is slightly amphiplatyan. Finally, the centrum of "Sanchusaurus" seems more 
markedly constricted ventrally than Gallimimus'. According to Makovicky's 
(1995) description of Ornithomimus, it resembles a second sacral centrum more 
in having a lateral fossa, wider dimensions and ventral flattening. 
Shenzhousaurus' first sacral centrum (homologous to the second in Gallimimus 
and Ornithomimus) has a highly constricted ventral edge as in "Sanchusaurus". 
It is not a posterior sacral, as it lacks a ventral sulcus. Thus "Sanchusaurus" 
seems to be represented by a centrum homologous to the ancestral neotheropod 
first sacral centrum and the ornithomimid second sacral centrum. It is 
indeterminate within Ornithomimosauria.
References- Osmolska, Roniewicz and Barsbold, 1972. A new dinosaur Gallimimus 
bullatus, n. gen. n. sp. (Ornithomimidae) from the Upper Cretaceous of 
Mongolia. Palaeontologica. Polonica. 27, 103-143.
Hasegawa, Kase and Nakajima, 1984. A large vertebrate fossil from the Sanchu 
Graben. Abstracts of the 91st Annual Meeting of the Geological Society of 
Japan. 219. [In Japanese] 
Hisa, 1985.
Makovicky, 1995. Phylogenetic aspects of the vertebral morphology of 
Coelurosauria (Dinosauria: Theropoda). M.S. thesis, Univ. Copenhagen, 311pp.
Hasegawa, Manabe, Kase, Nakajima and Takakuwa, 1999. An ornithomimid vertebra 
from the Early Cretaceous Sebayashi Formation, Sanchu Terrane, Gunma 
Prefecture, Japan. Bulletin of Gunma Museum of Natural History. 3, 1-6.

The first discovered element of Fukuiraptor may be a tooth from the type quarry 
nicknamed Tsuchikura-ryu by Azuma (1991) and referred to Megalosauridae. Currie 
and Azuma (2006) note 89% of the teeth from that quarry are from Fukuiraptor, 
whose teeth do possess the generalized carnosaur/megalosaur morphology. While 
several other Japanese nicknames have been inappropriately transformed into 
nomina nuda in the published literature, "Tsuchikurasaurus" is so far 
restricted to the internet, specifically due to the IVPP's dinosaur.net site. 
References- Azuma, 1991. Early Cretaceous Dinosaur Fauna from the Tetori Group, 
central Japan. Research on Dinosaurs from the Tetori Group (1). Professor S. 
Miura Memorial Volume, 55-69.
http://www.dinosaur.net.cn/museum/Tsuchikurasaurus.htm
Currie and Azuma, 2006. New specimens, including a growth series of Fukuiraptor 
(Dinosauria, Theropoda) from the Lower Cretaceous Kitadani Quarry of Japan. J. 
Paleont. Soc. Korea. 22(1), 173-193. 

Mickey Mortimer