Sarcocystis chalcidicolubris n. sp.: Recognition of the Life Cycle in Skinks of the Genus Chalcides and Snakes of the Genus Coluber

Abstract

The recognition of cyclic transmission of Sarcocystis chalcidicolubris n. sp. by snakes of the genus Coluber to skinks of the genus Chalcides is reported. Sarcocysts isolated from a naturally infected Chalcides ocellatus and orally administered to a Coluber ravergieri led to sporocyst shedding by the snake. After oral administration of these sporocysts to species of the genus Chalcides, microscopic sarcocysts, 124-275 jm long and 27-53 ,m wide were found 130 days postinfection (PI) in the musculature of the skinks. When sarcocysts of the experimentally infected Chalcides species were fed to snakes of the genus Coluber, infectious sporulated sporocysts were excreted as soon as 15-21 days for at least 3 mo. These sporocysts measured 10.8 (9.4-11.7) x 9.2 (8.2-9.9) Am. Based on morphological observations and repeated transmission experiments S. chalcidicolubris is described as a new species. Despite numerous reports on Sarcocystis species parasitizing reptiles either as intermedi- ate or as definitive hosts, so far only 1 species, Sarcocystis podarcicolubris, has been shown to cycle between poikilothermic intermediate and definitive hosts (Matuschka, 1981, 1987). Re- cently, the transmission of S. podarcicolubris by snakes of the genus Coluber to various lizard species of 3 different genera was experimentally demonstrated (Matuschka, 1985). In this con- text, skinks of the genus Chalcides were labora- tory bred to investigate the capability of S. po- darcicolubris to parasitize these reptiles as intermediate hosts. A routine check for parasites ofocellated skinks, Chalcides ocellatus, imported to establish reproductive groups in the labora- tory, revealed sarcocysts in the musculature of their tails. This study was carried out in order to elucidate the life cycle of this new Sarcocystis species. Ad- ditionally, results of transmission experiments, which were performed to determine host speci- ficity, are reported.