Jinju Formation

The Jinju Formation (Korean: 진주층; Hanja: 晋州層; RR: Jinju-cheung), also known as the Dongmyeong Formation (Korean: 동명층; Hanja: 東明層; RR: Dongmyeong-cheung) in some literature is an Early Cretaceous geologic formation in South Korea.^[2] Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.^[3] The depositional age of this formation spans from approximately 112.4 ± 1.3 to 106.5 million years ago (early Albian) based on detrital zircon U-Pb dating.^[4] It predominantly consists of black shale, with sandstone packets, deposited in a fluvial-lacustrine setting.

Jinju Formation
Stratigraphic range: Albian ~112.4–106.5 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Shindong Group
Underlies	Chilgog Formation, Iljig Formation
Overlies	Hasandong Formation
Thickness	1,000–1,800 m (3,300–5,900 ft)
Lithology
Primary	Shale
Other	Sandstone
Location
Coordinates	35.1°N 128.1°E / 35.1; 128.1
Approximate paleocoordinates	44.3°N 122.7°E / 44.3; 122.7
Region	Gyeongsang Province
Country	South Korea
Extent	Gyeongsang Basin(ko:경상 분지)
Type section
Named for	Jinju
Named by	Tateiwa, 1929[1]
Jinju Formation (South Korea)

A diverse arthropod fauna, including freshwater arthropods, spiders, and insects, is known from the formation. Other notable fossils known from the formation include several freshwater fishes, ostracods, and plants. This formation has also "attracted global ichnological attention" for the variety of important ichnofossils.^[5] Columnar and rod-shaped stromatolites have also been found here.^[6]

Fossil content

Plants

Plants of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Cupressinocladus	C. sp.[7]				The presence of this conifer indicates that a mixed type of the Tetori-Type and the Ryoseki-Type flora existed in this formation.
Ruffordia	R. sp.[8]				Schizaeaceae ferns
Cladophlebis	C. sp.[8]
Sphenopteris	S. sp.[8]
Onychiopsis	O. elongata[9]				leptosporangiate ferns
Brachyphyllum	B. japonicum[9]
Equisetum	E. cf. burchardti[10]

Spiders

Spiders of the Jinju Formation[11]
Genus	Species	Region	Member	Material	Notes	Image
Korearachne	K. jinju	Jinju			likely to be a lycosoid
Koreamegops	K. samsiki	Jinju			a lagonomegopid
Jinjumegops	J. dalingwateri	Jinju			a lagonomegopid
Mygalomorphae	indeterminate	Jinju
Araneomorphae	indeterminate	Jinju
Palpimanoidea	indeterminate	Jinju
"Cribellate Entelegynae"	"species 1" "species 2"	Jinju

Insects

Odonata

Dragonflies and damselflies of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Hemeroscopus	H. baissicus[12][13]	Sacheon and Jinju		Both nymphs and adults
Koreapodagrion	K. coloratus[14]	Jinju		Isolated wings

Dermaptera

Earwigs of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
cf. Pygidicranoidea[15]	indeterminate

Orthoptera

Orthopterans of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Panorpidium	P. spica[16]				A member of Elcanidae

Dictyoptera

Dictyopterans of the Jinju Formation[17]
Genus	Species	Region	Member	Material	Notes	Image
Cretophotina	C. smidovae				A member of Mantodea
Juramantis	J. jinjuensis J. geongonrigam
Bubosa	B. petrarosa				A member of Blattidae
Neoblattella	N. coockrock				A member of Ectobiidae
Perlucipecta	P. jinjuicola P. cyclopica P. major				A member of Mesoblattinidae
Praeblattella	P. tinctoria P. decolor
Mongoloblatta	M. koreaensis
Archimesoblatta	A. basopicta
Spinaeblattina	S. variabilitta
Jinjublatta	J. cascadaerrorum
Stictolampra	S. baqueuii				A member of Blaberidae
Holocompsa	H. scleroptera				A member of Corydiidae
Ioouoonool	I. taktobybolo
Asioblatta	A. jeongchonensis				A member of Raphidiomimidae
Cameloblatta	C. immaculata
Tayphoonoblatta	T. correntini
Ano	A. ale				A member of Liberiblattinidae
Brutalista	B. masivny
Blattula	B. pessimusestfinis				A member of Blattulidae
Elisama	E. baeki E. simplex
Ocellonlattula	O. gyongsangensis
Vrtula	V. jinjuensis
Memento	M. futuri				A member of Caloblattinidae
Sclerotermes[18]	S. samsiki	Jinju			A termite known only from an isolated wing, uncertain placement
Umenocoleus[19]	U. minimus				A member of Umenocoleidae
Pseudoblattapterix[19]	P. weoni
Petropterix[19]	P. koreaensis P. oculata P. nikdyviac
Blattapterix	B. reticulata
Alienopterus	A. imposter				A member of Alienopteridae
Recyklovany	R. koltoc
Caputoraptor	C. ganggu
Indeterminate	5 indeterminate taxa

Hemiptera

Hemipterans of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Corixidae[20]	indeterminate	Sacheon
Jinjupopovina	J. eosahwae[21]	Jinju			A member of Yuripopovinidae

Hymenoptera

Hymenopterans of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Korehelorus	K. jinjuensis[22]	Jinju			A parasitic wasp belonging to the family Heloridae
Hanguksyntexis	H. haeretica[23]	Jinju			A sawfly belonging to the family Anaxyelidae
Cretosphecium	C. jinjuensis[24]	Jinju			A wasp belonging to the family Angarosphecidae

Raphidioptera

Snakeflies of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Mesoraphidia[25]	M. koreensis M. phantasma				A member of Mesoraphidiidae

Neuroptera

Lacewings of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Tachinymphes	T. koraiensis[26]				A member of the family Mesochrysopidae.
Araripeneura	A. asiatica[27]				A member of Araripeneuridae
Araripenymphes	A. koreicus[27]				A member of Cratosmylidae

Coleoptera

Beetles of the Jinju Formation[28]
Genus	Species	Region	Member	Material	Notes	Image
Coptoclava[29]	C. sp.	Jinju and Gunwi		Nymph remains abundant; Adult remains relatively rare	A member of the extinct family Coptoclavidae. Similar to C. longipoda, but assigned to a yet undescribed species since C. longipoda is usually considered to be a species complex.
Megalithomerus[30]	M. magolhalmii				A member of Elateridae
Koreagrypnus[30]	K. jinju
Cretosaja[31]	C. jinjuensis				A member of Silphidae
Notocupes[32]	N. premeris				A member of Archostemata
Asiana[33]	A. pax
Brochocoleus[33]	B. sacheonensis				A member of Ommatidae
	B. cf. punctatus
Omma[33]	O. sp.
Zygadenia[33]	Z. cornigera
Laetopsia[34]	L. leei				A member of Hydrophiloidea
	L. cf. hydraneoides
	L. sp.
Cretotaenia[34]	C. pallida
Psacodromeus[35]	P. recta				A member of Trachypachidae
Necronectulus[35]	N. lazarus

Diptera

Flies of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Buccinatormyia[36]	B. gangnami				A member of the family Zhangsolvidae. Named after Gangnam Style, the famous K-Pop hit song

Crustaceans

Isopoda

Isopods of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Archaeoniscus[20]	A. coreaensis	Sacheon and Jinju			A freshwater occurrence of the genus Archaeoniscus

Ostracoda

Ostracods of the Jinju Formation[37][38]
Genus	Species	Region	Member	Material	Notes	Image
Scabriculocypris	S. yanbianensis	Jeongcheon
Cypridea	C. jinjuria C. khandae C. samesi[39]	C. jinjuria in Gwanghyeon
Mongolocypris	M. kohi[40]
Lycopterocypris	L. cf. celsa	Jeongcheon
Candona	C. sp.
Djungarica	D. sp.	Jeongcheon
Rhinocypris	R. sp.				Previously assigned to as Ilyocypris sp.

Spinicaudata

Clam shrimps of the Jinju Formation
Genus	Species	Region	Member	Material	Notes	Image
Yanjiestheria[41]	Y. kyongsangensis Y. chekiangensis Y. cf. wannanensis Y. jinjuensis Y. sp.

Vertebrates

Source:^[42]

Actinopterygii

Fishes of the Jinju Formation[43]
Genus	Species	Region	Member	Material	Notes	Image
Wakinoichthys[44]	W. aokii			Multiple complete skeletons	An osteoglossiform
Jinjuichthys[45]	J. cheongi	Jinju		Articulated skeletons	A possible ichthyodectiform, though this classification remains controversial[46]
Albuliformes	indeterminate
Sinamia	S. sp.			Articulated incomplete tail	An amiiform
Lepidotes	L. sp.			Articulated skeleton, missing the anterior part of the head	Largest fish found in this formation, reaching 40 cm (1.3 ft) in total length.
Elopiformes	indeterminate				A small fish, reaching 3 cm (1.2 in) in total length.

Archosauria

Reptiles of the Jinju Formation
Genus	Species	Region[47]	Member	Material	Notes	Image
Crocodyliformes indet.[48]		Goryeong		a right mandible
Titanosauriformes indet.[49][50]		Sacheon and Goryeong		teeth	A tooth from Sacheon was initially suggested to be of Asian Brachiosaurid by Lim, Martin and Baek (2001), but Barrett et al. (2002) and Choi & Lee (2017) consider it to be indeterminate titanosauriform. Meanwhile, another tooth from Goryeong was suggested to be of Diplodocoidea by Yun et al. (2007), but Choi and Lee (2017) also considered it indeterminate titanosauriform.
Pterodactyloidea indet.[49][51]		Goryeong		teeth	While the KPE 40001 suggested to be of Boreopterid origin by Choi & Lee (2017), Yun (2021) and Yun (2024) consider them to be Anhanguerian instead based on the morphological disparity from Boreopteridae and the results of two-dimensional geometric morphometric analyses.[52][53]

Mollusks

Bivalvia

Bivalves of the Jinju Formation[54]
Genus	Species	Region	Member	Material	Notes	Image
Plicatounio	P. naktongensis
Nagdongia	N. soni				The genus Nagdongia is considered to be synonymous with Nakamuranaia by some.
Trigonioides	T. jaehoi
Sphaeriun	S. coreanicum[55]

Gastropoda

Gastropods of the Jinju Formation[8]
Genus	Species	Region	Member	Material	Notes	Image
Brotiopsis	B. kobayashi				Dominant gastropod of the formation
Thiara	T. sp.
Viviparus[56]	V. sp.

Ichnofossils

Unnamed ichnofossils from the Jinju Formation include Ornithopod tracks and Caddisfly bioherms.^[6]

Ichnofossils of the Jinju Formation
Ichnogenus	Ichnospecies	Region	Member	Material	Notes	Image
Gyeongsangsauropus[57]	G. isp.	Jinju			Sauropod tracks
Grallator[58]	G. isp.	Jinju			Theropod track; similar to the ichnospecies G. yangi
Corpulentapus[58]	C. isp.	Jinju			Theropod track
Asianopodus[58]	A. isp.	Jinju			Theropod track
Minisauripus	M. isp.[5]	Jinju			One of the smallest known theropod tracks. Currently the oldest record of this ichnogenus from South Korea.
Dromaeosauriformipes[59]	D. rarus	Jinju			The smallest known non-avian dinosaur didactyl tracks possibly made by a small microraptorine, with indication of important flight behaviors such as flap-running, take-off, and landing.[60]
Dromaeosauripus[61]	D. jinjuensis	Namhae[47]			Didactyl tracks made by a 40 cm (1.3 ft) tall dromaeosaur.
Ignotornis	I. seoungjoseoi[62]	Sacheon			Bird Track
Jindongornipes	J. isp.[62]	Sacheon			Bird Track
Koreasaltipes[63]	K. jinjuensis	Jinju[47]			Traces left by a hopping mammal
Neosauroides	N. innovatus[64]	Jinju			The largest reported lizard trackway in South Korea.
cf. Chelichnus[65]		Sacheon[47]			Turtle trackway; first identified as Chelonipus isp.[66]
Ranipes[65]	indeterminate	Jinju			Oldest known frog trackway. Made by a species that hopped in short distances.
Crocodylopodus[67]	C. isp.	Sacheon and Jinju			First report of this ichnogenus from Asia.
Batrachopus	B. grandis[68]	Sacheon			Archosaur track made by either a bipedal crocodylomorph or therizinosaur;[69] the pterosaur trackway ichnospecies Haenamichnus gainensis from the Haman Formation is now assigned to this species as B. cf. grandis.[68] Paleontologist James I. Kirkland expresses doubts on the ichnogenus assignment.[70]
Pteraichnus	P. gracilis[71] "P. seopoensis"[72]				Pterosaur trackway. P. seopoensis is currently a naked name, since it was only described in a master's thesis.
Lockeia	L. gigantus[56]				Resting trace, made by bivalve tracemakers
Diplichnites	D. isp.[8]				Arthropod tracks
Coclichnus	C. isp.[8]				Trace by Annelida tracemakers
Radialimbricatus[73]	R. bitoensis				Potential tracemakers include arthropods, cnidarians or annelids
Protovirgularia[74]	P. dichotoma				First nonmarine occurrence of this ichnotaxon; possibly made by larvae of dragonfly[75]
Fictovichnus[76]	indeterminate				Probable insect cocoon or pupation chamber; the earliest record of an insect pupation structure probably associated with a burrow
Chondrites	C. isp.[77]
Palaeophycus	P. tubularis[77]
Helminthopsis	H. hieroglyphica[77]
Skolithos	S. magnus[77]
Taenidium	T. barretti[77]
Torrowangea	T. rosei[77]

See also

• ko:경상 분지 (Gyeongsang Basin)
• Geology of South Korea § Gyeongsang Basin
• List of dinosaur- bearing rock formations
  • List of stratigraphic units with indeterminate dinosaur fossils