Aspects of reproductive biology and the life cycle of Chonopeltis australis, a description of Dipteropeltis campanaformis Neethling, Malta and Avenant-Oldewage, 2014 and comments on distribution of Branchiura

Abstract: This thesis examines aspects of the biology of the crustacean Subclass Branchiura. A review of the systematics, the current understanding of biology, and the distribution of all known species is presented. This condensed retrospect of Branchiura recounts the present research on aspects of the anatomy, physiology, host–parasite interactions and phylogeny, and identifies points which may require further investigation. Distribution tables also present evidence of the confusion in taxonomy, especially in the genus Argulus. The first chapters investigate the reproductive biology of Chonopeltis australis Boxshall, 1976. Specimens of C. australis were collected from the Vaal River to maintain a breeding colony in the laboratory. The colony was monitored daily and records were kept of tank conditions, copulation, egg deposition, egg development, and the progression of the life-cycle. Apart from the adults, three of the expected nine stages of the life-cycle were collected and fixed. The differences between stages were highlighted using light and scanning electron microscopy. The life-cycle was found to be similar to that reported for C. brevis Fryer, 1961 and C. lisikili Van As and Van As, 1996 but, for this genus, a description of all the stages of the life-cycle is still lacking. The adult male and female reproductive system anatomy was examined further using histology. The male and female specimens were sectioned in multiple planes, stained using a trichrome stain, and micrographs were obtained. The micrographs were analysed and used to reconstruct the reproductive systems graphically. A description of the female reproductive system, oogenesis and egg laying is presented. The female system and oogenesis is similar to that of Argulus sp. and Dolops sp., but egg laying differs in that the female leans off the resting fish to deposit eggs on the surrounding substrate. The species has thus adapted to its inability to actively swim. The internal iii reproductive system of the male was found to be similar to that of D. ranarum (Stuhlmann, 1891), while the peg and socket structures on the third and fourth pair of legs were similar to the same structures of A. japonicus Thiele, 1900. The occurrence of a spermatophore is described, and the modification of a characteristic of Branchiura is suggested to accommodate for their existence. The second part of this study tested the hypothesis that there is more than one species of Dipteropeltis Calman, 1912. Specimens of Dipteropeltis hirundo Calman, 1912 were examined and compared to the description provided by Calman (1912). D. campanaformis Neethling, Malta, and Avenant-Oldewage, 2014 is described using light as well as scanning electron microscopy. The morphology and distribution of museum specimens are compared.D.Phil. (Zoology