OBSERVATION ON THE URINOGENITAL PAPILLA AND SEXUAL DIMORPHISM IN SOME INDIAN GOBIIDS (GOBIIDAE: TELEOSTEI)

Abstract

A thorough comparative study on the urinogenital papilla and sexual
dimorphism has been made for the first time in both the sexes of twelve Indian
gobiids- Glassogobius giuris (Han1ilton); Acentrogobius cyanomos (Bleeker);
Eleotriodes muralis (Valenciennes); Parapocryptes serperaster (Richardson);
Apocryptes bato (Hamilton); Scartclaos viridis (Hamilton); Boleophthalmus
boddarti (Pallas), Periophthalmus schlosseri (Pallas); P. koelreuteri (Pallas);
Taenioides anguillaris (Linnaeus); T. buchanani (Day); Odontamblyopus
rubicundus (Hamilton). The urinogenital papilla, originating as a free muscular
organ from the ventral surface of the body-wall and shortly behind anus, is
present in both the sexes. It is an important organ of primary sex recognition
in all species. In case of male the papilla is conical, broad at the base and
in female it is either flattened, distally truncated or bluntly rounded. The
presence of permanent colour mark over the specific region of the body
surface is another secondary sexual character in a few species. Besides,
colouration may also be a nuptial secondary sex character developed in some
during peak breeding season. The enlargement and colouration of the organ is
subject to seasonal variations parallel to the seasonal gonadal cycle. The
histological architecture of the papilla shows a high degree of cellular
specialization and an interrelationship to the urinary and genital ducts. The
functional efficacy and significance of the papilla in the breeding biology of
these fishes has been discussed.
Keywords : Gobiidae, Sexual dimorphism, Urinogenital papilla