New insights into morphological features of Hadjelia truncata (Spirurida: Habronematidae), as revealed by SEM

Hadjelia truncata (Spirurida: Habronematidae) is a nematode found in the gizzard of several avian species. However, it has been reported pathogenic only in pigeons ( Columba livia ), in which it causes severe ventriculitis. Scanning electron microscopy (SEM) was used to study the morphological aspects of adult worms of this nematode in detail. Males and females measured 6.5–9 and 12–16.5 mm, respectively. The bodies were straight with moderate uniform thickness in both males and females, narrowing at the anterior end. The cuticle was striated transversely. The mouth was surrounded by two lateral trilobed lips, and the dorsal and ventral interlabia were present. The two cephalic papillae were present on each side lodged just behind the upper and lower bases of each lip. Around the mouth, a large amphid was seen on each lip. At the anterior end of both male and female worms, an excretory pore on the ventral side and a pair of lateral cervical papillae were observed. In the female, the vulva was located at the anterior end of the body. The lips of the vulva protruded above the body surface, and the bluntly rounded posterior end showed an anal pore and two subterminal phasmids. The posterior end of the males curved ventrally, with large caudal alae supported by four pairs of stalked precloacal papillae, a single medial precloacal papilla, two pairs of postcloacal papillae, and a cluster of small papillae on the caudal extremity. Spicules were unequal and dissimilar.