Functional dynamics observations of haptoral armature in Mizelleus indicus (Jain 1957) Pandey et al. 2003

Abstract

The negative effect of monogenea on piscine host may vary in the host species. Genus Mizelleus (Monogenea: Ancyrocephalidae) was reported for the first time from the freshwater shark, Wallago attu (Bl. and Schn.) at Lucknow by Jain (1957). Haptor or opisthohaptor of monogenea which is more or less discoid muscular structure situated posteriorly, is the chief adhesive organ. It is usually provided with anchors and marginal hooklets. Anchors, ventral transverse bar, together with the additional supporting dorsal bars (patches) are active elements of haptor while, marginal hooklets serve as secondary supportive participants, whereas, the dorsal transverse bar can be treated as an inactive element in the whole organ of attachment. Functional dynamics detail of haptoral armature is almost unattended. The anchors in case of M. indicus (Jain 1957) Pandey et al. (2003) are disposed one against the other and used to act like four lobed grapnel like a spreader. All components of haptoral armature contribute in one way or another in the process of functional process. Interestingly the worms do not follow the same pattern of sequences during their movements. Various elements and factors are involved in the process. The authors tried to pinpoint the changes in the activity of one major element i.e., dorsal anchor. The movement and change in position/orientation of various elements with reference to dorsal anchors were observed and summarized. Present paper is rare effort in unexplored aspect in monogenea biology.

Keywords: Adduction and abduction; Functional morphology; Haptor; Monogenean.

Fig. 1

Different steps during adduction and abduction in M. indicus (Jain 1957) Pandey et al. (2003). a Haptoral armature in resting position. Dorsal anchors relaxed and ventral transverse bars resting on curvature of dorsal supporting bars (patch). b & c Ventral transverse bars exhibit activity resulting points of ventral anchors to open up. d–h Ventral transverse bars facilitates the anchorage of ventral anchor which initiates the outward movement in the points of dorsal anchors. i–m Marginal hooklets appears to facilitate the entanglement, dorsal transverse bar appears as an inactive element but it allows to give support while dorsal anchor point is on move resulting outward movement of points and firmness in piercing into the host tissue. n–t Median piece of ventral transverse bar allows consolidation steps. Ventral transverse bars further make points of ventral anchor to penetrate deep into host tissue and points of dorsal anchor enters further deep into the host tissue. Marginal hooklets still playing supportive role by entangling to the surrounding host tissue

Fig. 2

(Photomicrographs) Different steps during adduction and abduction in M. indicus (Jain 1957) Pandey et al. (2003). a Haptoral armature in resting position. Dorsal anchors relaxed and ventral transverse bars resting on curvature of dorsal supporting bars (patch). b & c Ventral transverse bars exhibit activity resulting points of ventral anchors to open up. d–h Ventral transverse bars facilitates the anchorage of ventral anchor which initiates the outward movement in the points of dorsal anchors. i–m Marginal hooklets appears to facilitate the entanglement, dorsal transverse bar appears as an inactive element but it allows to give support while dorsal anchor point is on move resulting outward movement of points and firmness in piercing into the host tissue. n–t Median piece of ventral transverse bar allows consolidation steps. Ventral transverse bars further make points of ventral anchor to penetrate deep into host tissue and points of dorsal anchor enters further deep into the host tissue. Marginal hooklets still playing supportive role by entangling to the surrounding host tissue