Abnormal development of Rhipicephalus sanguineus (Ixodidae).

Three malformed Rhipicephalus sanguineus specimens were noticed in a tick laboratory colony. These specimens had different degrees of twining, from an almost fused individual (with two anal pores) to a partially fused adult male, with four spiracular plates. One female was a heart-shaped specimen. with both body halves fused along a longitudinal axes, with four spiracular plates and two anal pores.