ABSTRACT

Biodiversity studies in search of endoparasitic acephaline gregarines of earthworms revealed a new species under the genus Rhynchocystis Hesse, 1909.

The species has been obtained from the seminal vesicles of the earthworm, Metaphire peguana. The parasite was identified using standard methodology.

Gamonts are solitary, elongated with a conical, enlarged head and blunt posterior end. The mature gamont measures 419.90- 430.95 (425.05±4.70) μm in length and the width at the widest portion is 44.2-50.83 (47.88±2.85) μm and 15.47-17.68 (16.50±1.14) μm in the posterior end. The nucleus is elongated and positioned at the posterior end. The nucleus measures 17.68-22.01 (19.74±1.95) μm×11.05- 15.47 (13.40±1.95) μm. The measurement of the mucron is 13.26-17.68 (15.47±1.86) μm×17.68-22.1 (19.44±1.71) μm. Gametocysts are ovoid with two unequal sized gametocytes. The gametocyst measures 95.03-97.24 (96.20±1.14) μm×77.35-81.77 (79.56±1.86) μm. Large and small gametocytes measure 57.46-61.88 (59.81±1.76) μm×70.72-75.14 (72.48±1.71) μm and 30.94-37.57 (34.47±2.74) μm×61.88-66.3 (64.38±1.84) μm respectively. Oocysts are biconical, measuring 11.05-15.47 (12.81±1.71) μm×6.63-8.84 (7.70±1.20) μm.

A new gregarine parasite species is described.

Keywords: Rhynchocystis silvae sp. nov, gregarine, earthworm, seminal vesicles, Bangladesh