# Intertrappean Beds

The Intertrappean Beds are a Late Cretaceous and early Paleogene geologic unit in India. These beds are found as interbeds between Deccan Traps layers, including the slightly older Lameta Formation. They consist a number of different subgroups and formations, and span the Cretaceous–Paleogene boundary.
Many mostly fragmentary fossils, especially of small vertebrates, are known from the formation. Indeterminate theropod and pterosaur remains have been recovered from the formation, as well as dinosaur eggs. The mammal genera Deccanolestes, Sahnitherium, Bharattherium, Indoclemensia, Indotriconodon and Kharmerungulatum have been recovered from several localities. The Early Eocene-aged Bamanbor locality in Gujarat preserves articulated freshwater fish specimens. A rich plant flora is known from the formation.

## Stratigraphy

Although often thought of as a contemporaneous unit that was formed in a single rapid eruption event, more studies that date the age of the volcanic beds indicate that the Deccan Traps did not erupt all at once. Instead, different portions appear to have erupted during different periods of time. This means that the Intertrappean Beds are best understood as a group of different volcanic-associate formations of varying ages.

### Divisions

Kale et al (2020) divided the group into the following provinces:
* Sahyadri Group or Western Province (age: Late Maastrichtian to Danian, ~67.5 to 62.5 mya)
* Satpura Group or Central Province
* Malwa Group (age: Late Maastrichtian, ~67.7 mya; likely the oldest group)
* Amarkantak Group or Mandla Province (age: early Paleogene, ~64.5 mya - unknown)
Mittal et al (2021) divided the group into the following provinces:
* Western Ghats-Central Indian Volcanic Province (WVP) (age: Late Maastrichtian to Danian)
* Saurhastra-Kutchh Province (age: ?Maastrichtian to early Eocene)
* Malwa Plateau Province (age: Late Maastrichtian)
* Mandla Lobe Province (age: early Paleogene)

### Formations
#### Chemostratigraphic definition

Kale et al (2020) divided the group as follows. Subgroups/formations are classified based on oldest to youngest.
* Wai Subgroup (youngest)
** Desur Formation
** Panhala Formation
** Mahabaleshwar Formation (~63.2 mya)
** Ambenali Formation
** Poladpur Formation
* Lonavala Subgroup
** Bushe Formation
** Khandala Formation
* Kalsubai Subgroup (oldest, ~67.5 mya)
** Bhimashankar Formation
** Thakurwadi Formation
** Neral Formation
** Igatpuri Formation
** Jawhar Formation

#### Lithostratigraphic definition

Kale et al (2020) divided the group as follows. Subgroups/formations are classified based on oldest to youngest.
* Sahyadri Group:
** Bombay Subgroup (~62.5 mya)
*** Borivali Formation
*** Elephanta Formation
** Khandala Subgroup (~67.5 to 63.2 mya)
*** Mahabaleshwar Formation (~63.2 mya)
*** Purandargarh Formation
*** Diveghat Formation
*** Karla Formation
*** Indrayani Formation
** Kalsubai Subgroup (oldest: ~67.5 mya)
*** Upper Ratangarh Formation
*** Lower Ratangarh Formation
*** Salher Formation
* Satpura Group:
** Karanja Formation (youngest)
** Buldhana Formation
** Chikli Formation
** Ajanta Formation
** Upper Ratangarh Formation
** Karanja Formation
** Buldana Formation
** Chikli Formation (oldest)
* Malwa Group:
** Singarchori Formation (youngest)
** Bargonda Formation
** Indore Formation
** Kankaria-Pirukheri Formation
** Kalisindh Formation
** Mandleshwar Formation
** Gaganwara Formation (oldest)
* Amarkantak Group:
** Kuleru Formation (youngest)
** Khamla/Kampla Formation
** Amarwara Formation
** Multai Formation
** Linga Formation
** Pipardehi Formation
** Dhuma Formation
** Mandla Formation (oldest, ~64.4 mya)
Within the newly-defined Saurhastra Group (age: Paleocene to early Eocene), the following divisions were found by Patel & Shah (2023):
* Ninama Basin:
** Ninama Limestone (youngest)
** Sukhbhadar Formation (oldest)
* Chotila Basin:
** Bamanbor Formation (youngest)
** Chotila Chert
** Rangpar Formation (oldest)

## Paleobiota

| Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon | Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited. |

### Fish

| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Anthracoperca | A. bhatiai | Naskal, Rangapur | | Otolith. | A percoid otolith. |
| Apateodus | A. striatus | Asifabad | | | An enchodontoid aulopiform. |
| Ariidae | incertae sedis | Naskal, Rangapur, Anjar | | Otolith. | An ariid catfish otolith. |
| ?Belonostomus | B. indicus | Nagpur | | | An aspidorhynchid. |
| Coupatezia | C. sp | Asifabad | | | An eagle ray. |
| Cyprinidae | incertae sedis | Deothan-Kheri | | | A cyprinid. |
| Dapalis | D. erici | Rangapur | | Otolith. | A serranid otolith. |
| "Eotrigonodon" | "E." wardhaensis | Asifabad | | | Initially described as tetraodontiform, but likely represent grasping teeth of pycnodonts. |
| Enchodus | E. sp | Asifabad | | | An enchodontoid aulopiform. |
| Horaclupea | H. intertrappea | Bamanbor | Early Eocene | Complete skeleton. | A clupeid. |
| Igdabatis | I. indicus | Kisalpuri & Piplanarayanwar | | | An eagle ray. |
| Indiaichthys | I. bamanborensis | Bamanbor | Early Eocene | Multiple complete skeletons. | A possible percoid. |
| "Indotrigonodon" | "I." ovatus | Asifabad | | | Initially described as tetraodontiform, but likely represent grasping teeth of pycnodonts. |
| "Lepidotes" | "L." sp | Asifabad | | | A lepisosteiform. |
| Lepisosteus | L. indicus | Kisalpuri & Piplanarayanwar | | | A gar. |
| Nandidae | incertae sedis | Deothan-Kheri | | | A nandid. |
| Osteoglossidae | incertae sedis | Kisalpuri & Piplanarayanwar | | | An osteoglossid of uncertain affinities. |
| Palaeolabrus | P. dormaalensis | Asifabad | | | A palaeolabrid. |
| Palaeopristolepis | P. chiplonkari | Bamanbor | Early Eocene | Multiple partial skeletons. | A questionable leaffish. |
| Palaeopristolepis | P. feddeni | Bamanbor | Early Eocene | Multiple partial skeletons. | A questionable leaffish. |
| "Perca" | "P." angusta | Bamanbor | Early Eocene | Skull. | A possible percoid, classification very doubtful. |
| Percomorpha | incertae sedis | Bamanbor | Early Eocene | Partial skeleton. | A percomorph of uncertain affinities. |
| Phareodus | P. sp. | Asifabad, Naskal & Marepalli | | | A bonytongue. |
| Polycanthidae | incertae sedis | Deothan-Kheri | | | A polycanthid. |
| "Pisdurodon" | "P." spatulatus | Asifabad | | | Initially described as tetraodontiform, but likely represent grasping teeth of pycnodonts. |
| Pycnodontidae | incertae sedis | Kisalpuri & Piplanarayanwar | | | A pycnodontid of uncertain affinities. |
| "Pycnodus" | "P." lametae | Asifabad | | | A pycnodontid. |
| Raja | R. sudhakari | Asifabad | | | A skate. |
| Rhombodus | R. sp. | Asifabad | | | A stingray. |
| Serranidae | incertae sedis | Deothan-Kheri | | | A serranid. |
| Siluriformes | incertae sedis | Kisalpuri & Piplanarayanwar | | | A catfish of uncertain affinities. |
| Sphenodus | S. sp. | Asifabad | | | A shark. |
| Stephanodus | S. lybicus | Asifabad & Marepalli | | | A pycnodontid. |

#### Otolith-based taxa

| Genus | Species | Location | Material | Notes |
| "Ambassidarum" | A. cappettai | Nagpur | Otolith | An ambassid otolith. |
| "Apogonidarum" | A. curvatus | Naskal, Rangapur | Otolith | A cardinalfish otolith. |
| "Blenniidarum" | B. sp | Rangapur | Otolith | A blenny otolith. |
| ?"Centropomidarum" | C. takliensis | Nagpur | Otolith | A possible snook otolith. |
| "Clupeidarum" | C. valdiyai | Nagpur, Rangapur | Otolith | A clupeid otolith. |
| "Clupeidarum" | C. sahnii | Nagpur, Rangapur | Otolith | A clupeid otolith. |
| "Gonorhynchidarum" | G. rectangulus | Nagpur, Rangapur | Otolith | A gonorynchid otolith. |
| "Heterotidinarum" | H. heterotoides | Naskal | Otolith | An arapaimine otolith. |
| "Notopteridarum" | N. nolfi | Naskal, Rangapur, Cheemalagutta | Otolith | A notopterid otolith. |
| "Osteoglossidarum" | O. deccanensis | Naskal, | Otolith | An osteoglossid otolith. |
| "Osteoglossidarum" | O. intertrappus | Naskal, | Otolith | An osteoglossid otolith. |
| "Percoideorum" | P. citreum | Naskal, Nagpur, Rangapur | Otolith | Percoid otoliths. |
| "Percoideorum" | P. nagpurensis | Naskal, Nagpur, Rangapur | Otolith | Percoid otoliths. |
| "Percoideorum" | P. rangapurensis | Naskal, Nagpur, Rangapur | Otolith | Percoid otoliths. |
| ?"Pristolepidinarum" | P. jaegeri | Nag | Otolith | A possible pristolepid otolith. |
| "Serranidarum" | S. sp. | Anjar | Otolith | A serranid otolith. |

### Amphibians

| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Gobiatidae | incertae sedis | Naskal | | | A gobiatid frog. |
| "Hemisotidae"/"Leptodactylidae" | incertae sedis | Naskal | | | A frog of uncertain affinities. |
| Indobatrachus | I. pusillus | Worli Hill | Early Paleocene | Multiple complete skeletons | A frog of uncertain affinities. |
| Pelobatidae | incertae sedis | Nagpur | | | A pelobatid frog. |
| Ranoidea | incertae sedis | Naskal | | | A ranoid frog. |
| Costata | incertae sedis | | | | A costatan frog |
| ?Caudata | incertae sedis | | | | A possible salamander. |

### Reptiles
#### Turtles

| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Carteremys | C. leithii | Worli Hill | Early Paleocene | Carapace, plastron, skull and partial mandible | A turtle of uncertain affinities. | |
| Sankuchemys | S. sethnai | Amboli Quarry | | Skull | A bothremydid turtle. | |

#### Lepidosaurs

| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Acrosphenodontia | Incertae sedis | Naskal | | Dentary with teeth. | An indeterminate rhynchocephalian. |
| "Agama" | A. sp. | Rangapur | | | An indeterminate agamid lizard. |
| Anguidae | Incertae sedis | Naskal | | | An indeterminate anguid lizard. |
| ?"Contogenys" | ?"C." sp. | Nagpur | | | An indeterminate scincomorph lizard. |
| Deccansaurus | D. palaeoindicus | Kesavi | Maastrichtian/Early Paleocene | Jaws & several osteoderms. | A scincoid lizard. |
| ?"Exostinus" | "E." estestai | Nagpur | | | An indeterminate xenosaurid lizard. |
| "Eumeces" | "E." sp. | Rangapur | | | An indeterminate scincid lizard. |
| Indophis | I. sahnii | Naskal | | Over 160 vertebrae. | A nigerophiid snake. |
| "Litakis" | "L." sp. | Nagpur | | | An indeterminate lizard. |
| "Pristiguana" | "P." sp. | Nagpur | | | An indeterminate iguanid lizard. |
| Serpentes | Incertae sedis | Naskal | | A trunk vertebra & left dentary. | A snake. |
| Serpentes | Incertae sedis | | | | Possibly a primitive form, |
| Madtsoiidae | Incertae sedis | | | Three individuals. | Madsoid snakes. |
| cf. Indophis | cf. I. sahnii | | | | Nigerophiidae snake. |
| Booidea | Incertae sedis | | | | Possibly a Booid snake. |

#### Crocodyliforms

| Genus | Species | Location | Material | Notes |
| Crocodylidae | incertae sedis | Worli Hill | Teeth and dentary. | A crocodylid crocodyliform. |
| Dyrosauridae | incertae sedis | Kisalpuri | Partial mandible, frontal, and vertebrae | A dyrosaurid crocodyliform. |
| Crocodyliformes | incertae sedis | Naskal | Teeth. | Shows similarities to Hamadasuchus and perhaps Mahajangasuchus. |

#### Dinosaurs

| Genus | Species | Location | Material | Notes |
| ?"Hypselosaurus" | "H." sp | Mohgaon Kalan | | A titanosaurian sauropod. |
| Massospondylus | M. rawesi | | Tooth | Previously thought to be Massospondylus now thought to have been an indeterminate Theropod. |
| Sauropoda | Incertae sedis | Asifabad, Ranipur, Anjar | Bones | Sauropod bones. |

##### Oogenera

| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Megaloolithus | baghensis | Kisalpuri | | Eggshell fragments | A Titanosaur egg. | |
| Subtiliolithus | kachhensis | Kisalpuri | | Eggshell fragments | A Enantiornithine bird egg. | |

#### Pterosaurs

| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Pterosauria | incertae sedis | Sirol-khal locality | | | An indeterminate dentulous pterosaur. May not be from the Maastrichtian. | |

### Mammals

| Genus | Species | Location | Material | Notes |
| Bharattherium | B. bonapartei | Kisalpuri | A fragmentary cheek-tooth. | A sudamericid mammal. |
| Deccanolestes | D. hislopi | Naskal microvertebrate site | Molars, calcanea, astralgi, humerus, ulna. | A eutherian mammal. |
| Deccanolestes | D. robustus | Naskal microvertebrate site | "Dental material and an astragalus". | A eutherian mammal. |
| Deccanolestes | D. narmadensis | Kisalpuri | "Isolated rear molar." | A eutherian mammal. |
| Indoclemensia | I. naskalensis | Naskal microvertebrate site | Right second Molar. | A eutherian mammal. |
| Indoclemensia | I. magnus | Naskal microvertebrate site | Left second Molar. | A eutherian mammal. |
| Indotriconodon | I. magnus | Kutch | Single lower Molar. | A eutriconodont mammal. |
| Kharmerungulatum | K. vanvaleni | Kisalpuri | Isolated right lower molar. | A eutherian mammal. |
| Sahnitherium | S. rangapurensis | Rangapur microvertebrate site | Upper Molar. | A eutherian mammal. |

### Arthropods

| Genus | Species | Location | Time Period | Notes |
| ?Buprestidae | Indeterminate | Maharashtra | Maastrichtian | A Jewel beetle. |
| Lomatus | L. hislopi | Maharashtra | Maastrichtian | A Jewel beetle. |
| ?Curculionidae | Indeterminate | Maharashtra | Maastrichtian | A Snout beetle. |
| Meristos | M. hunteri | Maharashtra | Maastrichtian | A Snout beetle. |
| Ostracoda | Indeterminate | Maharashtra | Maastrichtian | An Ostracod. |
| Palaeotanymecides | P. hislopi | Maharashtra | Maastrichtian | A Snout beetle. |

### Mollusca

| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Bamanboria | B. oblongis | Bamanbor | Early Eocene | Shells | A deccanoid freshwater mussel. |
| Chotilia | C. deccanensis | Bamanbor | Early Eocene | Shells | A deccanoid freshwater mussel. |
| Chotilia | C. trappeansis | Bamanbor | Early Eocene | Shells | A deccanoid freshwater mussel. |
| Chotilia | C. tuberculata | Bamanbor | Early Eocene | Shells | A deccanoid freshwater mussel. |
| Deccanoida | D. aleta | Bamanbor | Early Eocene | Shells | A deccanoid freshwater mussel. |
| Deccanoida | D. congruis | Bamanbor | Early Eocene | Shells | A deccanoid freshwater mussel. |
| Deccanoida | D. costaria | Bamanbor | Early Eocene | Shells | A deccanoid freshwater mussel. |
| Limnaea | sp. | Maharashtra | Maastrichtian | | A snail. |
| Valvata | sp. | Maharashtra | Maastrichtian | | A snail. |
| Paludina | sp. | Maharashtra | Maastrichtian | | A snail. |
| Physa | P. prinsepii | Maharashtra | Maastrichtian | | A snail. |

### Flora

| Genus | Species | Location | Material | Notes |
| Connaroxylon | C. dimorphum | Dhagaon, Mandla district | Wood | Affinities with Connaraceae. |
| Euphorbiotheca | E. deccanensis | | | Fruit, member of Euphorbiaceae. |
| Hyphaeneocarpon | | | | Fruit, member of palm tribe Borasseae. |
| Palmocarpon | | | | Fruit, member of palm tribe Cocoseae. |
| Palmoxylon | P. dindoriensis | | | Wood, member of palm subfamily Coryphoideae. |
| Pantocarpon | | | | Fruit, member of Torricelliaceae. |
| Phyllanthocarpon | P. singpurensis | | | Fruit, member of Phyllanthaceae. |
| Rhizopalamoxylon | | | | Palm rhizome, close affinities to Nypa. |
| Pediastrum | | | | Algae. |
| Lecaniella | | | | Algae. |
| Pierceites | P. deccanensis | | | A Dinocyst. |
| Aulacoseira | | | | A Diatom. |
| Azolla | | | | Member of Salviniaceae. |
| Crybelosporites | | | | Member of Marsileaceae. |
| Sparganiaceaepollenites | | | | Pollen grains, Member ofSparganiaceae/Typhaceae. |
| Marsilea | | | | Member Marsileaceae. |
| Regnellidium | | | | Member of Marsileaceae. |
| Nymphaeaceae indet. | | | | |
| Typhaceae indet. | | | | |
| Liliaceae indet. | | | | |
| Acanthaceae indet. | | | | |
| Pontederiaceae indet. | | | | |
| Ovoidites | | | | Member of Zygnemataceae. |
| Gabonisporis | | | | Pollen grains, member of Marsileaceae. |