Does the red blood cell in frogs undergo amitosis?
Unlike mammalian blood cells, blood cells in Amphibia are nucleated (as the paper in your link explains) and can perform cell division (here is an old paper from Acta Haematologica, 1954: https://www.karger.com/Article/Pdf/204534).

Your question is: is this division a regular mitosis or the so called amitosis? According to Barni et al., 1995, amphibian blood cells can perform amitotic cell division:


  The proliferation of haemopoietic cells, detected by the anti-BrdU labelling index, was accompanied by absence of mitotic cell division and the appearance of cells showing features of amitosis (e.g. nuclear constrictions with bundles of electron-dense chromatin)


Source: Barni, S., Fraschini, A., Prosperi, E., Vaccaronel, R. and Bernini, F. (1995) ‘Possible occurrence of amitotic cell division during haemopoiesis in the Urodeles’, Comparative Haematology International, 5(3), pp. 183–188. doi: 10.1007/bf00368042.