Middle East Journal of Applied Sciences ISSN 2077-4613 Volume : 07 | Issue :02 | April-June| 2017 Pages: 280-288 Corresponding Author: Mohammed Hasan Ibraheem, Department of Zoology, Faculty of Science, Minia University, El-Minia 61519, Egypt. E-mail: mohamhas@mu.edu.eg 288 On the Morphology of the Oxyurid Nematode Aplectana macintoshii (Stewart, 1914) Travassos, 1931 (Ascaridida: Cosmocercidae) from the Toad Bufo regularis Reuss in Egypt Mohammed Hasan Ibraheem Department of Zoology, Faculty of Science, Minia University, El-Minia 61519, Egypt. E-mail :mohamhas@mu.edu.eg Bahaa Kenawy Abuel-Hussien Abdel-Salam Department of Zoology, Faculty of Science, Minia University, El-Minia 61519, Egypt. Department of Biology, Quwiayha College of Science and Humanities, 11961, Shaqra University, Saudi Arabia. E-mail :bahaa.kenawy1@yahoo.com Al-Shimaa Mahmoud El-Morsi Department of Zoology, Faculty of Science, Minia University, El-Minia 61519, Egypt. E-mail : show.mhmoud@yahoo.com Received: 20 November 2016 / Accepted: 25 December 2016 / Publication date: 27 April 2017 ABSTRACT The aim of the present study was to characterize the morphological features of Aplectana macintoshii using light and scanning electron microscopy. Morphometric measurements of adult worms are given. Scanning electron microscopy revealed a transversely striated body and a triangular mouth opening. The latter is surrounded by three large oral lips and two pairs of thick cuticular flaps. The cephalic sense organs consist of a circle of 12 cephalic papillae (4 internal and 8 external) and a pair of large amphids. The excretory pore, the vulva and the anal opening of the female appeared as transverse slit-like openings transversal to the longitudinal axis of the body. The lateral alae extend along the length of the body from the cephalic extremity to the anal region and become disapparent beyond the anus. The body of both sexes is covered by minute somatic papillae arranged in six longitudinal rows. The posterior sense organs of the female are in the form of three post-anal sessile papillae, while those of the male are at least ten pairs of papillae arranged in post-cloacal, ad-cloacal and pre-cloacal positions. A pair of long, equal, sharply pointed spicules projects from the cloacal opening. The posterior end of the male is sharply bent ventrally and ends with a tapering spike. The latter bears variable number of randomly distributed caudal papillae. Deirids on the anterior end, as well as plectanes, rosette papillae, spines, caudal lateral alae or vesiculated papillae on the posterior end, were not observable in the present study. Key words: Aplectana macintoshii, Ascaridae, Bufo regularis, Cosmocercinae, Egypt, Nematoda, Oxyuridea. Introduction Nematode species of the genus Aplectana Railliet & Henry, 1916b are intestinal parasites of reptiles and amphibians (Yorke & Maplestone 1926, Travassos 1931, Baker 1980, 1987). They are cosmopolitan in geographical distribution, being encountered in Africa, China, Europe, Japan, India, South America and Malaysia (Baker 1987, Goldberg et al. 1993, Rago & Maharaj 2003, Yildirimhan et al. 2005, Bursey & Goldberg 2007, Holmes et al. 2008 and Ramalho et al. 2009). Aplectana macintoshii is the most widespread species of the genus and occurs in Africa, China, Europe, India, Malaysia and South America. It is now known from 37 species of frogs and toads, two species of lizards and one species of snakes (see Baker 1987). In Africa it has been reported from Cameroon (Rasheed, 1965) and Egypt (Baylis 1923). To our knowledge, there are few reports concerning A.