Trypanosoma (Herpetosoma) grosi kosewiense subsp n., the parasite of the yellow-necked mouse Apodemus flavicollis (Melchior, 1834)

Yellow-necked mice, Apodemus flavicollis, were examined for the presence of Herpetosoma trypanosomes at the Mazurian Lakeland, Poland. Bloodstream trypomastigotes were used for light microscopy investigations. In the host's blood, slender and stout trypomastigote stages of Trypanosoma grosi kosewiense subsp. n. were observed. The body length of the slender form ranged from 16.27 to 28.05 mum, mean 23.00 mum, and width from 0.79 to 2.56 mum, mean 1.43 mum. The free flagellum is 3.66-12.79 mum long, mean 7.59 mum. The kinetoplast is particularly large. Stout forms have a characteristic broad and short body and is 10.78-23.54 mum long, mean 14.74 mum, and 1.18-2.78 mum width, mean 1.76 mum. In contrast to the slender form of T. grosi kosewiense and many other trypanosomes, the broadest size of its body falls midway of the PN distance, not at the nuclear level. The free flagellum is 5.06-11.86 pm long. It is easy to notice the wide range of morphometric parameters. The results of light microscopy morphological description and morphometrical values of Trypanosma grosi Kosewiense subsp. n. were compared with those of Trypanosoma grosi Laveran et Pettit, 1909 parasitizing the wood Mouse, A. sylvaticus, and revealed that trypanosomes parasitizing the yellow-necked mouse are different in many investigated parameters.