The Jaisalmer Formation is a Middle to Late Jurassic-aged geologic formation located in India near the city of Jaisalmer that consists mainly of marine deposits.[1] The formation was first identified and defined by geologist Richard Dixon Oldham in 1886.[2]
Dinosaur remains are among the known fossils recovered from this formation.[3]
Strophodus jaisalmerensis, a hybodont, was named after this formation and the Jaisalmer District where its holotype was found.[4]
Sub-units
The Badabag, Fort, Joyan and Hamira members represent the Middle Jurassic Bajocian and Bathonian stages,[1] while the Jajiya and Kuldhar members represent the Middle Jurassic Callovian and the Late Jurassic Oxfordian stages.[1]
The Fort Member is the most extensively studied and consists of fine to medium grain sandstones and oolitic limestones.[5] The Badabag Member consists of intraformational conglomerate and is fossil bearing.[6]
Paleoenvironment
The Jaisalmer district of India is a landlocked district in the state of Rajasthan. However, during the Middle Jurassic, the Jaisalmer Formation was located on the Tethyan coast of Gondwanan India. A marine paleoenvironment is supported by the presence of Hybodont sharks.[4] The Kuldhar Member Limestone contained carbonate microfacies that also indicate a depositional environment composed mainly of lagoons, shoals and open marine environments.[7]
Paleofauna
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Dinosaurs
Sauropods
| Sauropods of the Jaisalmer Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Locality | Material | Notes | Photos |
| Turiasauria indet.[6] | Indeterminate | Chandoo Village quarry | Fragmentary tooth | A turiasaur | |
| Tharosaurus[8] | T. indicus | Jethwai Village | Partial cervical, dorsal, and caudal vertebrae and a dorsal rib | A potentially dubious eusauropod | |
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Theropods
| Theropods of the Jaisalmer Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Locality | Material | Notes | Photos |
| Spinosauridae indet.[9] | Indeterminate | Chandoo Village quarry | Pedal ungual phalanx | Possibly the oldest spinosaurid | File:Pedal ungual phalanx from the Bathonian of Jaisalmer Basin, India. Specimen RAJ JAIS CVQS002.png |
| Averostra indet.[10] | Indeterminate | Chandoo Village quarry | Isolated tooth | A possible allosauroid, ceratosaur, or non-spinosaurid megalosauroid | |
Other reptiles
| Reptiles of the Jaisalmer Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Locality | Material | Notes | Photos |
| Crocodylomorpha indet.[6] | Indeterminate | Chandoo Village quarry | Scutes | ||
| Neodiapsida indet.[6][10] | Indeterminate | Chandoo Village quarry | Teeth | Either a sauropterygian, thalattosaurian, choristodere or an ichthyosauromorph. | |
Fish
| Fishes of the Jaisalmer Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Locality | Material | Notes | Photos |
| Hybodontiformes indet.[11] | Indeterminate | ||||
| Strophodus | S. jaisalmerensis | Jethwai village | Teeth | A hybodont shark. | |
| S. indicus[12] | Chandoo Village quarry | ||||
| S. magnus[12] | Chandoo Village quarry | ||||
| S. medius[12] | Chandoo Village quarry | ||||
| Planohybodus | P. aff. grossiconus [12] | Chandoo Village quarry | Teeth | A hybodont shark. | |
| Osteichthyes indet.[10] | Indeterminate | Chandoo Village quarry | Teeth and scale | Found along with an averostran tooth. | |
| Eomesodon[13][14] | E. sp. | Jethwai Village | Prearticular dental plate and isolated teeth | Oldest East Gondwanan Pycnodont. | |
Crustaceans
| Crustaceans of the Jaisalmer Formation | |||||
|---|---|---|---|---|---|
| Genus | Species | Locality | Material | Notes | Photos |
| Cytherella[15] | C. indica | ||||
| Micropneumatocythere[15] | M. joyanensis | ||||
| Progonocythere[15] | P. khoslai | ||||
| Trichordis[15] | T. minuta | ||||
Ichnofossils
- ?Bichordites sp. – Ichnofossils[16]
- Planolites sp. – Ichnofossils[16]
- Rhizocorallium irregulare – Ichnofossils[16]
- Rhizocorallium jenense – Ichnofossils[16]
- Taenidium serpentinum – Ichnofossils[16]
- Thalassinoides sp. – Ichnofossils[16]
References
- ↑ 1.0 1.1 1.2 Review for "Microfacies and diagenetic overprints in the limestones of Middle Jurassic Fort Member (Jaisalmer Formation), Western Rajasthan, India: Implications for the depositional environment, cyclicity, and reservoir quality. Geological Journal({Template:Date).
- ↑ Cite error: Invalid
<ref>tag; no text was provided for refs namedOldham86 - ↑ Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 593–600. Template:ISBN.
- ↑ 4.0 4.1 Hybodont sharks from the Jurassic of Jaisalmer, western India. Historical Biology({Template:Year).
- ↑ Narayanan, K., Subrahmanyan, M., Srinivasan, S., (1961). Geology of Jaisalmer. Unpublished report, Oil and Natural Gas Corporation Dehradun, India.
- ↑ 6.0 6.1 6.2 6.3 The first turiasaurian sauropod of India reported from the Middle Jurassic (Bathonian) sediments of Jaisalmer Basin, Rajasthan, India. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen({Template:Date).
- ↑ Microfacies and stable isotope analysis of Kuldhar Member Limestone (Callovian–Oxfordian), Jaisalmer Basin, western Rajasthan: implications for depositional environment and diagenetic evolution. Carbonates and Evaporites({Template:Date).
- ↑ Fossils of the oldest diplodocoid dinosaur suggest India was a major centre for neosauropod radiation. Scientific Reports({Template:Year).
- ↑ First Jurassic evidence of a possible spinosaurid pedal ungual from the Jaisalmer Basin, India. Rivista Italiana di Paleontologia e Stratigrafia({Template:Year).
- ↑ 10.0 10.1 10.2 First Theropod Record from the Marine Bathonian of Jaisalmer Basin, Tethyan Coast of Gondwanan India. Rivista Italiana di Paleontologia e Stratigrafia({Template:Date).
- ↑ An assemblage of Middle Jurassic hybodonts from Jaisalmer Basin, western India. Historical Biology: An International Journal of Paleobiology({Template:Year).
- ↑ 12.0 12.1 12.2 12.3 A small assemblage of marine hybodont sharks from the Bathonian of the Jaisalmer Basin, India. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen({Template:Year).
- ↑ Oldest East Gondwanan pycnodont fishes (Neopterygii, Pycnodontiformes) from the Middle Jurassic (Bathonian) of Jaisalmer, western India. PalZ({Template:Date).
- ↑ Middle Jurassic (Bajocian) pycnodont fishes from the Jaisalmer Basin, western India. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen({Template:Year).
- ↑ 15.0 15.1 15.2 15.3 Middle Jurassic Ostracodes from Joyan Member, Jaisalmer Formation, Jaisalmer, Rajasthan, India. Paleontological Journal({Template:Year).
- ↑ 16.0 16.1 16.2 16.3 16.4 16.5 Kulkarni, K.G., Borkar, V.D., Petare, T.J., (2008). Ichnofossils from the Fort Member (Middle Jurassic), Jaisalmer Formation, Rajasthan. Journal of the Geological Society of India, 71, 731-738