The cloacal complex in Pseudocordylus melanotus and in Cordylus cordylus (Sauria: Cordylidae)

[摘要] ENGLISH ABSTRACT: The cloacal anatomy of PJeudocordylus melanotus and Cordylus cordylus wasexamined macroscopically and by light microscopy. The cloacal subdivisions arethe coprodaeum, the urodaeum and the proctodaeum. Both the coprodaeum andthe proctodaeum typically start as sphincter-like structures. However, the borderbetween the coprodaeum and urodaeum is not well delimited. The start of thecloaca from the intestine is marked by a change in epithelium, from consisting ofcolumnar and goblet cells to a columnar epithelium consisting of mucoussecreting cells. The urinary bladder extends ventrally from the coprodaeumurodaeumpart of the cloaca and is connected with it by means of a stalk. Themost striking sexual differences in the cloacal complex anatomy are associatedwith the urodaeum. Females possess anterior urodaeal limbs which are reducedin males. The urudaeum off em ales exhibits tall dorsal folds which are reducedor absent in males. In females the urogenital ducts (uteri and ureters) openseparately through the dorsal wall of the cloaca - the uteri in the anterior part ofthe urodaeum and the ureters in the coprodaeum-urodaeum cavity. In males thevas deferens and ureter on each side coalesce to open conjointly into thecoprodaeum-urodaeum cavity by means of a short ductus urogenital is. Thisjunction is in approximately the same position as the junction of the uretr withthe cloaca in females. Two types of cloacal glands were observed in the cordylidspecies examined Dorsal and ventral glands were found laterally on both sidesof the proctodaeum in males and females, hut were more pronounced in males.Urodaeal glands were observed only in the urodaeal walls of females.Pronounced seasonal variation was observed in the secretory activity of theluminal lining of the urodaeum of all females examined (both species) and in theurodaeal gland epithelia of one C. cordylus female. Neither of the cordylidspecies show any seasonal variation in the structure of the dorsal and ventral glands in any of the sexes. Little variation in cloaca) anatomy occurred betweenthe two cordylid species. However, the urodaeal limbs in most of theP.melanotus females examined, stretch further anteriorly than in C.cordylus.The intraspecific variations observed were primarily associated with the relativeposition of the coprodaeum-urodaeum Junction as well as the position of thejunction between the urinary bladder stalk and the cloaca ( coprodaeum and/orurodaeum). The relatively thick connective tissue ventral to the proctodaeummay serve as 'gliding surface' when the cloaca is pushed backwards duringcopulation. If sperm are stored in the cordylid species examined, it wouldprobably be in the vas deferens of the males.

[发布机构] Stellenbosch University