Observation on Monocystis constricta n. sp. (Protozoa: Apicomplexa: Monocystidae) from an Indian earthworm, Eutyphoeus quaripapillatus Michelsen, 1907.

A biodiversity survey of aseptate gregarines in earthworm hosts in the Calcutta district of West Bengal State revealed the existence of a new species of aseptate gregarine under the genus Monocystis Stein, 1848. The monocystid gregarines obtained from the earthworm host, Eutyphoeus quaripapillatus Michelsen, 1907 have been identified as a new species. The mucron was indistinct. The gamonts are elongated, ovoid, have a hood like structure at the anterior end and measure 150.1-212.4 (188.1+/-2.1) micromx66.1-112.1 (72.3+/-1.1) microm. The gametocysts are ellipsoid and measure 92.3-136.3 microm (111.2+/-2.1)x78.3-114.4 microm (82.6+/-3.6) microm. Prominent syzygy was apparent. Oocysts are navicular, measuring 14.1-22.3 (18.1+/-3.2) micromx9.1-15.2 (11.9+/-1.1) microm.