Heteroptychodus
Heteroptychodus is an extinct genus of hybodont that lived in Asia during the Early Cretaceous period. It had low, rounded durophagous teeth that are covered in ridges. Species have been reported from Japan, Mongolia, Malaysia, Thailand, Southern China, and possibly Kyrgyzstan. Fossils have been found in freshwater environments.

Cuny, Gilles · CC BY 4.0 · via GBIF. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.
On record
Recorded, not inferred- Sits inside
- HybodontinaePBDB
- Diet
- carnivorePBDB, for Chondrichthyes
- Life habit
- nektonicPBDB, for Chondrichthyes
- Motility
- actively mobilePBDB, for Chondrichthyes
Time the record covers
At least 15 million years on record.
The record covers at least 137.05 Mya to 121.4 Mya. No occurrence read is dated outside 149.2 Mya to 100.5 Mya.
17 occurrences of Heteroptychodus on record, most of them in the Early Cretaceous. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.
When
17 occurrencesThese are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. More on what this infers.
Found in
7 formations
- Sao Khua Formation · Khorat Group6
- Khok Kruat Formation · Khorat Group6
- Kamo Formation · Matsuo Group1
- Phu Kradung Formation · Khorat Group1
- Sebayashi Formation · Sanchu Group1
- Temus Shale Formation · Tembeling Group1
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The named rock units Heteroptychodus has been recovered from, largest first. Drawn where the rock is now, not where it formed.
Heteroptychodus and its relatives
Early CretaceousWhere Heteroptychodus and its relatives were recorded in the Early Cretaceous.
Found in the same rock
86 taxa- Spinosauridae9 sites
- Theropoda7 sites
- Hybodus4 sites
- Siamamia4 sites
- Testudines4 sites
- Thaiodus ruchae4 sites
- Actinopterygii3 sites
- Goniopholididae3 sites
- Isanemys srisuki3 sites
- Isanodus paladeji3 sites
- Osteichthyes3 sites
- Pterosauria3 sites
- Bivalvia2 sites
- Crocodylia2 sites
- Crocodyliformes2 sites
- Kizylkumemys khoratensis2 sites
- Lanxangichthys2 sites
- Lonchidion khoratensis2 sites
- Neosuchia2 sites
- Ornithischia2 sites
- Semionotidae2 sites
- Theriosuchus2 sites
- Trionychoidae2 sites
- Acrorhizodus khoratensis1 site
The Paleobiology Database records 16 sites for Heteroptychodus, and this reads all of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.
This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.
Entered from
13 references- Fossil assemblage from the Khok Pha Suam locality of northeastern, Thailand: an overview of vertebrate diversity from the Early Cretaceous Khok Kruat Formation (Aptian-Albian)4
- Dinosaur fauna from the Lower Cretaceous of Phu Kao-Phu Phan Kham, northeastern Thailand: a review and update2
- The first sauropod dinosaur from the Lower Cretaceous Khok Kruat Formation of Thailand enriches the diversity of somphospondylan titanosauriforms in southeast Asia1
- Ornithischian dinosaurs in Southeast Asia: a review with palaeobiogeographic implications1
- New vertebrate fossil site from the Early Cretaceous Sao Khua Formation, Sakon Nakhon Province, northeastern Thailand1
- Phu Din Daeng, a new Early Cretaceous vertebrate locality on the Khorat Plateau, NE Thailand1
- Fossil vertebrate remains from Kut Island (Gulf of Thailand, Early Cretaceous)1
- Hybodont sharks from the Lower Cretaceous Khok Kruat Formation of Thailand, and hybodont diversity during the Early Cretaceous1
- [III. Paleontological study of the Yamanaka Group]1
- A sinraptorid theropod (Dinosauria: Saurischia) from the Phu Kradung Formation of northeastern Thailand1
- Siamosuchus phuphokensis, a new goniopholidid from the Early Cretaceous (ante-Aptian) of northeastern Thailand1
- A new hybodont shark assemblage from the Lower Cretaceous of Thailand1
Each of the 17 occurrences read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. 1 further reference is not listed. Entries link to doi.org where the Paleobiology Database holds an identifier, and to its own record where it does not. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.
Media and terms
Media content1

Picture of Heteroptychodus
- Source
- GBIF
- Credit
- Cuny, Gilles
- Licence
- CC BY 4.0
- Commercial use
- the licence allows it
No 3D scan of Heteroptychodus was found in Sketchfab.
Smithsonian Open Access and MorphoSource were not reached for this taxon, so this list is what the others held rather than everything there is.
The description on this site
- Licence
- CC BY-SA 4.0
This is what the site found, which is not the same as what exists.
Keep going
What may have been alongside itHybodontinae through timeFormations of the Early CretaceousThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Yabe and Obata 1930