Morphology, Life History, and Development of the Acanthocephalan Mediorhynchus grandis Van Cleave, 1916

Abstract

Synonyms: Heteroplus grandis (Van Cleave, 1916) of Van Cleave, 1918. Heteroplus grandis (Van Cleave, 1916) of Baer, 1925. Empodius grandis (Van Cleave, 1916) of Travassos, 1924. Mature females 27 to 51 mm in length by 0.8 to 1.4 mm in width. Mature males 7 to 12 mm in length by 0.6 to 0.8 mm in width. Anterior and posterior ends of body flexed ventrally. Body slightly expanded just posterior to proboscis. Fully extended proboscis, cone-shaped, 0.57 to 0.86 mm in length, divided into anterior and posterior regions by insertion of proboscis receptacle. Anterior region 0.28 to 0.42 mm long, posterior region 0.29 to 0.44 long. Diameter of proboscis near apex (level of most anterior hooks) 0.14 to 0.21 mm; at level of insertion of proboscis receptacle 0.28 to 0.43 mm; at base 0.35 to 0.79 mm. Anterior region of proboscis possesses 18 more or less longitudinal rows of hooks with 4 to 5 hooks per row, each hook provided with posteriorly directed root. Average total number of hooks