Genital papillaegenital papillae:
1-3 pairs of extrusible finger-like to button-like projections, usually retracted into in the genital vestibule of acariform mites; sometimes formed as sessile disks around the genital opening; thought to be osmoregulatory structures; modified or multiplied and dispersed over the body in many freshwater mites. Genital papillae are absent in the larva, but may be added ontogenetically: protonymphs have one pair, deutonymphs two pairs, and tritonymphs (and adults) three pairs. The tritonymphal pair of papillae is often lost. The serially homologous Claparède's organ is usually present in the larvae (and prelarvae) of mites exhibiting genital papillae in nymphs and adults (Oudeman's Rule).
are present in many Acariformes. In the generalized ancestral life cycle, they are sequentially added as follows: larva (0 pairs), protonymphprotonymph:
the first nymphal stage or instar, usually octopod.
(1 pair), deutonymphdeutonymph:
(also deuteronymph) the second nymphal stage or instar.
(2 pairs), and tritonymphtritonymph:
the third, and final, nymphal stage or instar present in Opilioacarida, Holothyrida, Argasidae, and many Acariformes.
(3 pairs), with adults retaining the 3 tritonymphal pairs. Sometimes, the number of genital papillaegenital papillae:
1-3 pairs of extrusible finger-like to button-like projections, usually retracted into in the genital vestibule of acariform mites; sometimes formed as sessile disks around the genital opening; thought to be osmoregulatory structures; modified or multiplied and dispersed over the body in many freshwater mites. Genital papillae are absent in the larva, but may be added ontogenetically: protonymphs have one pair, deutonymphs two pairs, and tritonymphs (and adults) three pairs. The tritonymphal pair of papillae is often lost. The serially homologous Claparède's organ is usually present in the larvae (and prelarvae) of mites exhibiting genital papillae in nymphs and adults (Oudeman's Rule). may be reduced to 1–2 pairs. For example, in most Astigmata, tritonymphs and adults do not add genital papillaegenital papillae:
1-3 pairs of extrusible finger-like to button-like projections, usually retracted into in the genital vestibule of acariform mites; sometimes formed as sessile disks around the genital opening; thought to be osmoregulatory structures; modified or multiplied and dispersed over the body in many freshwater mites. Genital papillae are absent in the larva, but may be added ontogenetically: protonymphs have one pair, deutonymphs two pairs, and tritonymphs (and adults) three pairs. The tritonymphal pair of papillae is often lost. The serially homologous Claparède's organ is usually present in the larvae (and prelarvae) of mites exhibiting genital papillae in nymphs and adults (Oudeman's Rule)., so the maximum number of genital papillaegenital papillae:
1-3 pairs of extrusible finger-like to button-like projections, usually retracted into in the genital vestibule of acariform mites; sometimes formed as sessile disks around the genital opening; thought to be osmoregulatory structures; modified or multiplied and dispersed over the body in many freshwater mites. Genital papillae are absent in the larva, but may be added ontogenetically: protonymphs have one pair, deutonymphs two pairs, and tritonymphs (and adults) three pairs. The tritonymphal pair of papillae is often lost. The serially homologous Claparède's organ is usually present in the larvae (and prelarvae) of mites exhibiting genital papillae in nymphs and adults (Oudeman's Rule). is 2 pairs.
Many oribatid mites have well developed ovipositors ending in three setose lobes.
Author: David E. Walter
Content last updated Sept. 2006, unless indicated otherwise
Lucid key player updated Sept. 2025
idtools.org
