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aqua 27(1)_Oryzias andrewi

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Volume 27, Issue 1 – 22 March 2021

Tyson R. Roberts, Priyankar Chakraborty, Kranti Yardi, and Prasun Mukherjee: Oryzias andrewi, new species of slender ricefish from Bengal, India, related to the highly specialized western indian coastal Horaichthys setnai Kulkarini 1940 (Cyprinodontiformes, Adrianichthyidae), pp. 21-35

 

 

 

 

 

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SINGLE PAPER


Volume 27, Issue 1 – 22 March 2021

Tyson R. Roberts, Priyankar Chakraborty, Kranti Yardi, and Prasun Mukherjee: Oryzias andrewi, new species of slender ricefish from Bengal, India, related to the highly specialized western indian coastal Horaichthys setnai Kulkarini 1940 (Cyprinodontiformes, Adrianichthyidae), pp. 21-35

Abstract

Oryzias andrewi, the first known elongate or slender (as opposed to deeper-body) Indian species of the rice-fish genus Oryzias is described based on specimens collected in widely separated localities in the Ganges basin in Assam and Bengal. It is more closely related than any previously known species to the extremely specialized and even more slender adrianichthyid Horaichthys setnai, widely and continuously distributed in estuarine habitats and fresh water habitats along nearly the entire coast of the Western Ghats in the Indian subcontinent. O. andrewi and H. setnai agree in having a well-defined black stripe parallel to the anal fin base (not the same as a thinner black line over the anal fin distal pterygiophores), in having only 4 -5 branchiostegal rays (6 in some other Oryzias), and in having all or nearly all of the rays in the anal fin simple (not branched), a condition also found in many other species of Oryzias. The most substantial characters distinguishing Horaichthys from our new species of slender Oryzias are its more highly specialized reproductive structures, increased number of vertebrae, and unusually numerous enlarged teeth on distal end of premaxilla in males.