Thiruvananthapuram, Feb 11 (IANS): Four new fish species have been found in Kerala, the college professor who made the discovery has said.

The new new species have been named Puntius nelsoni, Puntius nigronotus, Systomus chryseus and Systomus rufus, said Mathews Plamoottil, a zoology professor at Kollam's Baby John Memorial Government College.

"Detailed articles describing these new species have been published in international publications like 'Journal of Research in Biology' and 'International Journal of Fauna and Biological Studies'," Plamoottil told IANS.

Elaborating, he said the body and fins of Puntius nelsoni are yellowish in colour, the head is deeper, the snout shorter and the mouth wider. It was discovered at Kallumkal in Thiruvalla, at the place where Pamba and Manimala rivers merge.

The Puntius nigronotus was discovered at Mananthavady in the hilly Wayanad district. Its dorsal fin is black in colour, the lateral line scales are greater than its closest relatives and its dorsal fin has more rays.

Systomus chryseus was discovered from Keezhvaipur near Thiruvalla. It is golden in coloured and its pectoral fin is greatly elongated.

Systomus rufus was discovered from Venpala, also near Thiruvalla. Its fins are red in colour.

"It is interesting to note that a new species of the genus Systomus is being discovered after one-and-a-half century from Kerala. All the four new species have received a Zoo bank register number from the International Commission of Zoological Nomenclature, the worldwide scientific authority for naming new animals. The new fish have been deposited in the museum of the Zoological Survey of India at Kolkata and Kozhikode," the professor said.

The Kerala State Biodiversity Board, the custodian of the state's rich biodiversity, said Kerala is home to 242 species of inland fish.