Abstract. Laboratory work was conducted to elucidate the life cycle of the South African gnathiid isopod, Gnathia africana Barnard, 1914. The natural fish hosts of this temporary parasite, the super klipfish Clinus superciliosus (Linnaeus, 1758), were exposed to gnathiid larvae in the laboratory. It was found that G. africana has three larval stages, consisting of three unfed (zuphea) and three fed (praniza) stages. First-, second-and third-stage zuphea larvae took an average of 2 h 18 min, 2 h 43 min and 10 h 8 min respectively to complete their feeding and the first-and second-stage praniza moulted at 8 and 10 days respectively into the next zuphea stage. Three to six days after its last blood meal, the sex of the third and final praniza stage could be determined by the presence of either a testis or two ovaries in the dorsal pereon. Male larvae moulted into adult males between 8 and 10 days post feeding. Female larvae moulted at approximately 17 days into adult females. The life cycle and ecology of members of the family Gnathiidae have intrigued scientists for more than two centuries. Even now the information available on these aspects of gnathiid biology is scanty. To the authors' knowledge the life cycle of only the following six of the more than 170 described gnathiid species has been researched in any detail: Gnathia maxillaris (Montagu,
Abstract. Haemogregarina bigemina Laveran et Mesnil, 1901 was examined in marine fishes and the gnathiid isopod, Gnathia africana Barnard, 1914 in South Africa. Its development in fishes was similar to that described previously for this species. Gnathiids taken from fishes with H. bigemina, and prepared sequentially over 28 days post feeding (d.p.f.), contained stages of syzygy, immature and mature oocysts, sporozoites and merozoites of at least three types. Sporozoites, often five in number, formed from each oocyst from 9 d.p.f. First-generation merozoites appeared in small numbers at 11 d.p.f., arising from small, rounded meronts. Mature, second-generation merozoites appeared in large clusters within gut tissue at 18 d.p.f. They were presumed to arise from fan-shaped meronts, first observed at 11 d.p.f. Third-generation merozoites were the shortest, and resulted from binary fission of meronts, derived from second-generation merozoites. Gnathiids taken from sponges within rock pools contained only gamonts and immature oocysts. It is concluded that the development of H. bigemina in its arthropod host illustrates an affinity with Hemolivia and one species of Hepatozoon. However, the absence of sporokinetes and sporocysts also distances it from these genera, and from Karyolysus. Furthermore, H. bigemina produces fewer sporozoites than Cyrilia and Desseria, although, as in Desseria, Haemogregarina (sensu stricto) and Babesiosoma, post-sporogonic production of merozoites occurs in the invertebrate host. The presence of intraerythrocytic binary fission in its fish host means that H. bigemina is not a Desseria. Overall it most closely resembles Haemogregarina (sensu stricto) in its development, although the match is not exact.
Abstract. Twenty two percent (22/98) of intertidal fishes of 10 species captured in South Africa at Koppie Alleen, De Hoop Nature Reserve (south coast) and Mouille Point, Cape Town (west coast), harboured single or combined infections of haemogregarines, trypanosomes and an intraerythrocytic parasite resembling a Haemohormidium sp. The haemogregarines included the known species Haemogregarina (sensu lato) bigemina (Laveran et Mesnil, 1901) Siddall, 1995 and Haemogregarina (sensu lato) koppiensis Smit et , while Haemogregarina (sensu lato) curvata sp. n. was observed in Clinus cottoides Valenciennes and Parablennius cornutus (L.) at Koppie Alleen. This last haemogregarine is characterised particularly by its distinctly curved gamonts. Also at Koppie Alleen, squash and histological preparations of 9/10 leeches, Zeylanicobdella arugamensis De Silva, 1963, taken from infected C. cottoides and P. cornutus contained developmental stages of H. curvata and/or trypanosomes, but these were absent from haematophagous gnathiid isopods (Gnathia africana Barnard, 1914) taken from infected fishes. It is suspected that Z. arugamensis transmits the haemogregarine and trypanosomes simultaneously between fishes, a double event unreported previously from the marine environment.
Blood films were examined from 154 wild and captive tortoises from four provinces of South Africa, including Gauteng, Kwazulu-Natal, North West and Western Cape. The five species of chelonians studied were Chersina angulata (Schweigger), Kinixys belliana belliana (Gray), K. lobatsiana Power, K. natalensis Hewitt, and Stigmochelys pardalis (Bell). Two species of haemogregarines, previously reported from Mozambique, were identified in blood films, namely Haemogregarina fitzsimonsi Dias, 1953 and Haemogregarina parvula Dias, 1953. Additional stages of development (trophozoites and probable meronts, merozoites and immature gamonts) in blood preparations from South Africa warranted the redescription of H. fitzsimonsi. A variety of hosts and broad host distribution range were observed for this haemogregarine, with all five species of tortoises parasitized, wild and captive, from all four provinces, in all seasons. In contrast, only two individuals of K. b. belliana and one S. pardalis, all three captive in Kwazulu-Natal, contained H. parvula with encapsulated stages resembling those of Hemolivia mauritanica (Sergent et Sergent, 1904). For H. fitzsimonsi, parasite prevalences, but not parasitaemias, were significantly higher in captive than wild S. pardalis; captive female S. pardalis also showed a significantly greater prevalence of infection than males, but younger, lighter hosts were not significantly more heavily parasitized than older, heavier individuals. The ticks, Amblyomma marmoreum Koch, 1844 and A. sylvaticum (De Geer, 1778), found attached to some tortoises, may prove to be definitive hosts for the two species of haemogregarines observed.
The genus Cymothoa Fabricius, 1793 is revised for southwestern Indian Ocean waters. Cymothoa borbonica Schioedte & Meinert, 1884 and C. eremita Brünnich, 1783 are redescribed. Cymothoa rotundifrons Haller, 1880, from Mauritius lacks type material and the host is unknown, therefore it is here relegated to nomen dubium. Cymothoa sodwana sp. nov., from Trachinotus botla (Carangidae), collected from the Kwazulu-Natal coast of South Africa, is described and is distinguished by the large, ovoid, hunched body with rugose dorsal surfaces; the anterolateral angles of pereonite 1 are narrow and rounded reaching half the length of the cephalon; the ischium of pereopod 7 has a large protrusion and pereonite 7 which laterally overlaps the pleon margins, extending posteriorly to the pleotelson.
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