your specimen as mentioned by Dr Syed and Rocktim has affinity towards Mauritia arabica. In specific, it is close to M. arabica asiatica and M. arabica imanis. Both these species have more of a circular pigment clusters on the dorsal side that slowly fades away towards the ventral side. The more of a prominent circular pigment clustering is found in M. grayana, M. histrio and M. maculifera. Still, as suggested by all, a careful assessment has to be made.
Many thanks for detailed answers and suggestions. In this matter I need some identification key books for careful assessment. I was wondering if you could help me with this matter.
You may try these guides. You may not find any specimen in the guide exactly matching with yours. So please exercise your own discretion in final determination or establishing close affinities.