Monday, May 16, 2011

Fish skull from Palana Formation at Hadla–Bhatiyan, District Bikaner, Rajasthan

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Fish skull from Palana Formation at Hadla–Bhatiyan, District Bikaner, Rajasthan

The present paper reports for the first time a fossil fish skull from the Palana Formation of the Bikaner – Ganganagar Basin in north-western India. Except for some algal and fungal remains1,2, a
rich pollen and spore assemblage3,4 and a variety of foraminifers5–8, no mega fossils have been reported
from the Palana Formation of Paleocene – Eocene age9. The Palana Formation – an important source of lignite in western Rajasthan is characterized by the association of grey clay, grey and greenish-grey to variegated shales, carbonaceous shale, sandstone and lignite.

A well-preserved fish skull was discovered at a depth of about 90 m from the surface when a well was being dug in a field in Hadla–Bhatiyan village (27° 46'05":73° 03'15") about 45 km south-west of Bikaner town in western Rajasthan (Figure 1). Lithological succession of the study area, based on data from the well at Hadla–Bhatiyan is given in Table 1. The Palana Formation has been observed to rest unconformably over the Badhaura Formation of Permian age, in an exploratory well drilled by the Oil and Natural Gas Corporation at Pugal-1 village. However, the rocks of the Palana Formation show a gradational contact with the overlying rocks of the Marh Formation, Lower Eocene-age, which in turn is disconformably overlain by the Lower to Middle Eocene rocks of the Jogira Formation.

The specimen is the fossilized skull of an Actinopterygian – a fresh water fish (Figure 2 a and b), at present preserved in the Department of Geology, Faculty of Science, Jai Narain Vyas University, Jodhpur, India. The head measures about 11 cm in length and 8.8 cm in width. Total length of the maxilla and premaxilla is about 5.8 cm. The diameter of the eye is 1.4 cm. Dentary

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Figure 1. Location map of the study area (R, Rajasthan).

has a length of about 5.8 cm. Teeth are sharp and backwardly curved. Lower teeth are larger than the upper ones. Upper teeth are 19 ´ 2 in number. In the middle part of the dentary the teeth are quite distinct and show an exposed length of 0.5 cm, whereas the unexposed length is about 0.55 cm. Size of the operculum is about 4.6 ´ 5.2 cm and the suboperculum is 3.2 ´ 1.5 cm in size. Interoperculum lies below the suboperculum and posterior to articu-lum. Preoperculum is not well preserved. The opercular series is highly developed with the prominent opercular bone on the lateral side. The mouth opening is large and extends beyond the eyes.

The anatomy of the skull suggests that the fish had a surface feeding character and carnivorous habit. A tentative identification (Table 2) suggests that the fish may be Silurid (A. Sahni, personal communication) similar to those reported from the Green River Formation (Eocene) of south-western Wyoming in USA10.

However, one of the reviewers has suggested that the morphology of the skull and teeth resemble that of Brachaetus – an Osteoglossid, known from the Eocene rocks of London11. Fresh water fish belonging to the family Osteoglossidae (group Osteoglossomorpha) have been reported from the Lower Eocene sequences of the Himalayan region, particularly, the Subathu Formation12,13 and also from many parts of peninsular India14–18. But there is no report of fossil fish from the Tertiary rocks of north-western Rajasthan.

Fossil fish fauna belonging to the family Osteoglossidae have been reported from Late Cretaceous to Eocene and Oligocene sediments of North America, South America, Africa (Congo, Tanzania and Nigeria), Australia, Denmark, England and Sumatra19–21.

The present discovery of the fossil Osteoglossid from the Palana Formation of Bikaner in western Rajasthan, supports the fact that Osteoglossids had their origin in India11,22 contrary to the prevailing view that they had their origin in Africa23,24.

Further detailed study of the specimen may provide some valuable information about the age of the Palana Lignite and its depositional environment.

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Figure 2 a. Right lateral view of the fossilized fish skull. b, Left lateral view of the fossilized fish skull.

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Figure 3. Line diagram of the right lateral view of fossilized skull of the fish, prepared by superimposing it on Figure 2.


    2. Rao, A. R., Curr. Sci., 1957, 26, 177.
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  19. De Muizon, C., Gayet, M., Lavenu, A., Marshall, L. G., Sige, B. and Villaroel, C., Geobios, 1983, 16, 747.
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  21. Cappetta, H., Palaeovertebrata, 1972, 5, 179.
  22. Patterson, C., in The Evolving Biosphere (ed. Forey, P. L.), British
    Museum of Natural History London, 1981, p. 265.
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ACKNOWLEDGEMENTS. I thank Prof. Ashok Sahni of Punjab University Chandigarh, Dr K. Kumar of Wadia Institute of Himalayan Geology, Dehradun, and Dr R. S. Rana of Kumao University, Nainital for their help in the identification. Thanks are also due to Dr D. Mohan and Dr A. Purohit of JNV University, Jodhpur, Dr S. Kaushik of Dungar College, Bikaner, and Mr B. S. Mehta and Mr P. S. Shekhawat of Department of Mines and Geology, Rajasthan for their help. Assistance received from Mrs S. Paliwal and Mr B. Paliwal is also gratefully acknowledged.

B. S. PALIWAL

Department of Geology,

Faculty of Science,

Jai Narain Vyas University,

Jodhpur 342 005, India



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