Annual reproductive pattern in the dassie Procavia capensis     

M. van der Merwe  J.D. Skinner 《African Zoology》2013,48(3):130-135

Proximate factors influencing the reproductive pattern and rate in dassies are examined in an area subject to marked seasonal climatic variation. The influence of photoperiod is confirmed with no modifying influence by either temperature or rainfull during the period of the study. Testicular and ovarian activity was related, showing a peak in ovulation and fertilization between the period mid-March and mid-April. Of 49 pregnant females collected between June and December, 83% had either two or three embryos/fetuses. Growth curves for differing litter sizes have been calculated. Failure to increase litter size appears to be related more to a conservative ovulation rate than to ova not fertilized or fetal wastage, although ova loss increased with increasing ovulation rate.  相似文献   

Fetal development of the bat Miniopterus schreibersi natalensis     

M. van der Merwe 《African Zoology》2013,48(3):172-182

Prenatal development in the fetus of Miniopterus schreibersi natalensis is discussed. Due to the long period of delayed implantation in this subspecies, the age of even the smallest fetuses, where the fore-limb buds just become visible will be around 150 days. The most reliable criterion for age determination proved to be body mass, and all fetal ages were estimated by using the equation t = W^1/3/0,0145 + 144.  相似文献   

Studies on the Motility and Cryopreservation of Rainbow Trout (Salmo Gairdneri) Spermatozoa     

G. van der Horst  H.M. Dott  G.C. Foster 《African Zoology》2013,48(4):275-279

The very short duration of vigorous movement (1 1/2 to 7 min) in fresh water and physiological solutions make trout spermatozoa difficult subjects for cryopreservation studies. Solutions consisting of 250 to 280 mmol sucrose and 5 to 12% dimethyl sulphoxide (DMSO) (4 parts) did not activate trout spermatozoa (1 part), but after dilution with fresh water vigorous motility could be fully restored. These sucrose-DMSO solutions were employed in cryopreservation studies. Using straws and a fast freezing — fast thawing procedure, post-thaw dilution with fresh water resulted in 25%-60% of spermatozoa becoming motile, all with vigorous forward progression. Some existing methods for the cryopreservation of other freshwater fish spermatozoa were repeated on trout without success.  相似文献   

Intestinal Protozoa of the African Elephant Loxodonta Africana (Blumenbach)     

K. Eloff Anette  W. van Hoven 《African Zoology》2013,48(2):83-90

The digestive tract of 15 elephants from South Africa and two from Zaïre were sampled in order to determine the identity, density and population composition of the intestinal protozoa. The following orders were represented: Gymnostomatida, Trichostomatida and Entodiniomorphida. Altogether 17 species were identified, of which three are new. The new species as well as a new genus are described.  相似文献   

Multiple births in Schlieffen's bat,Nycticeius schlieffenii (Peters, 1859) (Chiroptera: Vespertilionidae) from the southern African subregion     

M. van der Merwe  I.L Rautenbach 《African Zoology》2013,48(1):48-50

Nycticeius schlieffenii is a monestrous species that breeds during the spring months in the northern parts of the Kruger National Park. During spring 1983 the average number of corpora lutea in 11 Nycticeius schlieffenii females was 3,1 (range 1 -4), with the average number of fetuses recorded 2,8. In the present study this bat has been found to be a polyovular seasonal breeder, giving birth to as many as three young per estrous cycle.  相似文献   

Physiological changes during the ovarian cycle of the female rock lizard,Agama atra (Sauria: agamidae)     

J.H. van Wyk 《African Zoology》2013,48(4):253-260

Seasonal morphometric and physiological changes associated with vltellogenesis in the female agamid lizard, Agama atra are described. Vitellogenic activity during August - September marked the onset of the breeding season. It is suggested that at least two clutches were ovulated during the breeding season. Large abdominal fatbodles deposited prior to the winter months were possibly utilized to meet metabolic demands during winter and the onset of vitellogenesis during early spring (August - September). Follicular growth and fatbody deposition coincided with low plasma cholesterol levels. The liver index and total plasma proteins did not show a clear seasonal pattern. Of the seven plasma protein fractions, Fraction 2 (‘human beta-globulin’ mobility) increased during vltellogenesis while the foremost migrating proteins (‘human albumin’ mobility) showed a compensatory decrease. Total plasma calcium levels increased during vitellogenesis. The oviducts remained hypertrophied throughout the breeding season, while progesterone levels increased following each ovulation cycle in the presence of corpora lutea and remained elevated until oviposition. The onset of the second vitellogenic cycle (December) coincided with high progesterone levels.  相似文献   

Sessile peritrichs (Ciliophora: Peritricha) from freshwater fish in the Transvaal,South Africa     

Sophié Viljoen  J.G. van As 《African Zoology》2013,48(3):79-96

Sessile peritrichs (Ciliophora: Peritricha) were collected from freshwater fish in lakes, rivers, streams and fish-ponds in the Transvaal, South Africa Nine species of the genus Apiosoma Blanchard, 1885 are described, i.e. seven new species; A. caulata sp.n., A. curvinucleata sp.n, A. micralesti sp.n., A. mothlapitsis sp.n., A. obliqua sp.n., A. phiala sp.n. and A. viridis sp.n., and two known species; A. nasal is (Timofeev, 1962) and A. piscícola Blanchard, 1885. One new species of the genus Ambiphrya Baabe, 1952 is described, i.e. A. neobolae sp.n. A new sgenus, Scopulata gen.n. is proposed for species with a broad scopula and compact macronucleus. Two previously described Scyphidia species are incorporated in this genus, i.e. S. dermata (Viljoen & Van As, 1983) comb.n. and S. epibranchialis (Viljoen & Van As, 1983) comb.n., as well as a new species, S. constricta sp.n. Compendiums of all the known fish-associated species of these genera are provided.  相似文献   

The effect of cat Felis catus predation on three breeding Procellariidae species on Marion Island     

P.J.J. van Rensburg  M.N. Bester 《African Zoology》2013,48(4):301-305

Breeding success of Pterodroma macroptera, Procellaria aequinoctialis and Pachyptila vittata salvini in three cat-free and three control areas were used to evaluate the effects of cat Felis catus predation on the avifauna of Marion Island. Breeding success of all three species was significantly higher in the combined cat-free areas than in the combined control areas. However, breeding success in one cat-free area failed to show a significant difference from its particular control area, probably as a result of higher skua (Catharacta antarctica) predation inside the cat-free area. Chicks of P. macroptera and P. aequinoctialis were especially vulnerable to cat predation, since cats can enter their nesting burrows. P. macroptera was seriously affected by cat predation because it is the most abundant of only two winter-breeding petrels. Significant changes in the number of nest visits by these petrels during their breeding season followed hatching dates, which in turn were concomitant with, or were followed by significant differences in the combined breeding success between the cat-free and control areas. The cat-free areas show that an elimination of cat predation would still favour the recovery of the petrel population.  相似文献   

Observations on the attachment of a piscine gill parasitic ergasilid (Crustacea: Copepoda)     

W.H. Oldewage  J.G. van As 《African Zoology》2013,48(4):313-317

The attachment of the piscine gill parasite, Ergasilus mirabilis Oldewage & van As, 1987 is described by means of scanning electron microscopy and light microscopy. A variety of sensory structures occur on and around the host contact surface of the parasite and proliferation of gill tissue occurs at the site of attachment. It would appear that this proliferation of host tissue results from the feeding behaviour of the parasite rather than the actual attachment thereof.  相似文献   

A key for the identification of African piscine parasitic Ergasilidae (Copepoda:Poecilostomatoida)     

W.H. Oldewage  J.G. van As 《African Zoology》2013,48(1):42-46

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