Two new skink-endoparasitic species of Meteterakis (Nematoda, Heterakidae, Meteterakinae) from East Asian islands

Abstract

Here, two new nematodes of Meteterakis Karve, 1930 from Taiwan and the western Japanese Archipelago that are endoparasitic to scincid lizards are described. The Taiwanese Meteterakis formosensis sp. n. and the Japanese Meteterakis occidentalis sp. n. can be distinguished from other congeners by the following characteristics: spicules 437–537 μm in length in M. formosensis sp. n. and 359–538 μm in M. occidentalis sp. n.; spicules with narrow alae, funnel-shaped, proximal ends ventrally bent; prevulval flap well-developed; gubernaculum mass absent; preclocal sucker with diameter of 35–47 μm in M. formosensis sp. n. and of 32–36 μm in M. occidentalis sp. n.; 9–15 caudal papillae on both lateral sides in M. formosensis sp. n. and 10–14 in M. occidentalis sp. n.; and relatively narrow lateral alae, ending at region near proximal end of spicule in male or at region anterior to anus in female. Meteterakis formosensis sp. n. is distinguished from M. occidentalis sp. n. by possessing spicules with hyaline pointed distal ends and well-developed cuticular backing structures. The present study suggests that lateral alae can be used as diagnostic character among the Meteterakis species, and it revealed that meteterakine nematodes mature in the host’s small intestine and then migrate to the rectum to oviposit.