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

Mackay, Henry Calvin (1993)

Thesis (M. Sc.) -- University of Stellenbosch, 1993.

Thesis

ENGLISH ABSTRACT: The cloacal anatomy of PJeudocordylus melanotus and Cordylus cordylus was examined macroscopically and by light microscopy. The cloacal subdivisions are the coprodaeum, the urodaeum and the proctodaeum. Both the coprodaeum and the proctodaeum typically start as sphincter-like structures. However, the border between the coprodaeum and urodaeum is not well delimited. The start of the cloaca from the intestine is marked by a change in epithelium, from consisting of columnar and goblet cells to a columnar epithelium consisting of mucous secreting cells. The urinary bladder extends ventrally from the coprodaeumurodaeum part of the cloaca and is connected with it by means of a stalk. The most striking sexual differences in the cloacal complex anatomy are associated with the urodaeum. Females possess anterior urodaeal limbs which are reduced in males. The urudaeum off em ales exhibits tall dorsal folds which are reduced or absent in males. In females the urogenital ducts (uteri and ureters) open separately through the dorsal wall of the cloaca - the uteri in the anterior part of the urodaeum and the ureters in the coprodaeum-urodaeum cavity. In males the vas deferens and ureter on each side coalesce to open conjointly into the coprodaeum-urodaeum cavity by means of a short ductus urogenital is. This junction is in approximately the same position as the junction of the uretr with the cloaca in females. Two types of cloacal glands were observed in the cordylid species examined Dorsal and ventral glands were found laterally on both sides of 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 the luminal lining of the urodaeum of all females examined (both species) and in the urodaeal gland epithelia of one C. cordylus female. Neither of the cordylid species show any seasonal variation in the structure of the dorsal and ventral glands in any of the sexes. Little variation in cloaca) anatomy occurred between the two cordylid species. However, the urodaeal limbs in most of the P.melanotus females examined, stretch further anteriorly than in C.cordylus. The intraspecific variations observed were primarily associated with the relative position of the coprodaeum-urodaeum Junction as well as the position of the junction between the urinary bladder stalk and the cloaca ( coprodaeum and/or urodaeum). The relatively thick connective tissue ventral to the proctodaeum may serve as 'gliding surface' when the cloaca is pushed backwards during copulation. If sperm are stored in the cordylid species examined, it would probably be in the vas deferens of the males.

AFRIKAANSE OPSOMMING: Die kloakale anatomie van Pseudocordylus melanorus en Cordylus cordylus is makroskopies en histologies ondersoek. Die drie onderafdelings van die kloaka is die koprodeum, die urodeum en die proktodeum. Beide die koprodeum en proktodeum hegin tipies as sfinkteragtige strukture. Die oorgang vanaf die intestinum na die proktodeum word gekenmerk deur 'n verandering in die tipe epiteelselle - vanaf die kolomepiteel van die intestinum wat bestaan uit kolomen bekervormige selle na 'n kolomepiteel wat slegs uit slym-sekreterende selle bestaan. Die grens tussen die koprodeum en die urodeum is nie duidelik afgebaken nie. Die urinêre blaassteeljie is 'n ventrale uitsakking van die koprodaeum-urodeum gedeelte en verhind die urinere blaas met die kloaka. Die grootste verskil in kloakale anatomie tussen mannetjies en wyfies word aangetref in die urodeum. In wyfies verleng die urodaeum as twee 'bene' na voor, dorsaal van die koprodeum, terwyl urodeale verlengings ('bene') na voor in mannetjies afwesig is. In teenstelling met die urodeum van die wyfie, wat dorsaal redelik gevou is, is die wand van die mannetjie net effens gevou. In wyfies open die urogenitale huise (uteri en ureters) apart in die kloaka - die uteri in die voorste urodeum gedeelte en die ureters meer na agter, in die koprodeum-urodeeum holte. In mannetjies sluit die vas deferens en die ureter aan beide kante bymekaar aan, voordat dit deur middel van 'n gemeenskaplike opening in die koprodeum-urodeum holte open. Laasgenoemde urogenitale opening is omtrent in dieselfde posisie as die ureters se aansluiting in die kloaka van die wyfie. Twee tipes kloaka kliere is in die twee gordelakkedis species wat ondersoek is, aangetref. Dorsale- en ventrale kliere wat in mannetjies meer uitgesproke is, word dorso- en ventro-lateraal aan beide kante van die proktodeum aangetref. Die defnitiewe funksies van bogenoemde kliere is nog nie bekend nie, alhoewel daar heelwat hieroor gespekuleer word. Urodaeale kliere, wat met die wande van die urodeum geassosieerd is, word net in wyfies aangetref. Seisoenale variasie is waargeneem in die sekreterende aktiwiteit van die urodeale epiteel en ook van die urodaeale kliere van een C. cordylus wyfie. Hierdie seisoenale variasie is moontlik geassosieerd met die voortplantingsiklus van die dier. Geen seisoenale variasie is in die struktuur van die dorsale- en ventrale kliere aangetref nie. Die kloakale anatomie van die twee gordelakkedis species stem baie ooreen. Die urodeale gedeelte in die meeste P. melanotus wyfies wat ondersoek is, strek egter verder na voor as in die geval van C. cordylus. Die waargenome intraspesifieke variasies staan veral in verband met die posisie van die urinêre blaassteeltjie se aansluiting met die koprodeum, urodeum of albei. Die posisie van die koprodeum-urodeum-aansluiting kan ook binne dieselfde spesie varieer. Die relatief dik bindweefsel, ventraal van die koprodeum kan moontlik as 'glyvlak' dien wanneer die kloaka agtertoe gedruk word, tydens kopulasie.

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