Aquatic Parasite Observatory

Aristocleidus hastatus (Mueller, 1936)

    • Species Name: Aristocleidus hastatus (Mueller, 1936)
    • Synonyms: Urocleidus hastatus (Mueller, 1936)
    • Taxonomy: Animalia, Platyhelminthes, Monogenea, Dactylogyrida, Ancyrocephalidae, Aristocleidus hastatus
    • Description: Adult stage as described by Mueller, 1936: This species was common on the gills of the striped bass. Total length 0.4 mm., width 0.05 mm. Haptor well set off from body. Four large hooks present, supported by two transverse bars. Ventral pair curved, with un-divided roots. Dorsal pair angular, with divided roots. Ventral supporting bar much longer than dorsal. A delicate chitinous fin passes forward from the middle of the dorsal bar. Twelve marginal hooklets present. Measure-ments: ventral hooks, greatest measurement in a straight line, 0.046 mm.; dorsal hooks 0.048 mm. Ventral supporting bar 0.036 mm.; dorsal bar 0.019 mm. in length. Width of haptor 0.079 mm., length 0.058. Cirrus a curved delicated chitinous tube, supported by an immovable chitinous guide, consisting of the thickened wall of the cirrus vestibule. This differs from the accessory piece of Cleidodiscus, which is freely mov-able, and attached only at the proximal end. At its base the cirrus expands to join the ejaculatory duct. The vagina occurs a short distance in back of the cirrus on the right margin, and consists of a shallow vestibule or vulva, of circular outline, with convex, heavily chitinized floor, into which, from one side, opens the vagina as a delicate tube of about the diameter of the cirrus. It pursues a spiral course, making one complete turn and then passing to the interior. Pharynx large, about 0.033 mm. in diameter; four eyes prominent, the posterior pair provided with conspicuous lenses.
    • Life Cycle: Direct lifecycle parasites “the eggs of oviparous monogeneans (i.e., Dactylogyridae, Capsalidae, and Ancyrocephalidae) often have appendages that either slow movement in the water column or allow them to be easily trapped in mucus or other organic material. When the free-swimming ciliated larvae (oncomiracidia) emerge from the eggs, they are carried to a new host by water currents as well as by their own movement” (Reed et al., 2012).
    • Sources: Reed, P., Francis-Floyd, R., Klinger, R., and Petty, D. 2012. Monogenean Parasites of Fish. University of Florida IFAS extension. EDIS. Accessed Jan. 15 2016.
    • APO Parasite Records: (by Life Cycle)

  • University of Colorado Boulder