Turritella declivis Adams & Reeve,in Reeve, 1849 (Mollusca: Gastropoda) – a South African not an Australian species,and a characteristic component of the Agulhas Bank benthos

The name Turritella declivis, as described by Adams and Reeve in the ‘The Zoology of the Voyage of HMS Samarang’ (Adams & Reeve 1848-1850), is currently used for two distinct species of turritellid gastropod, one inhabiting the Agulhas Bank off South Africa and the other occurring off the Australian coast. Examination of the type material clearly shows that the name is referable to the southern African species. The Australian species must henceforth be known as Turritella captiva Hedley, 1987, a name previously regarded as a junior synonym of T. declivis. The original type locality ‘China Seas’ is erroneous, as was often the case with material collected during the voyage of the Samarang. It is emended to be the Agulhas Bank, over much of which T. declivis is common and may, in places, be hugely abundant, forming Turritella-dominated benthic communities. Such communities have been recorded in other parts of the world and are frequently associated with seasonal upwelling events, but have not previously been documented off South Africa.     

Distribution and reproduction of the reef fish Petrus rupestris (Pisces: Sparidae) off the coast of South Africa

The red steenbras (Petrus rupestris) is endemic to the south and south-east coasts of South Africa and is the largest member of the family Sparidae. Morphometric relationships between length and mass are given for whole and eviscerated fish. The size distribution of P. rupestris is related to locality and water depth. Juveniles and sub-adults are common in shallow (< 50 m) Cape waters between False Bay and East London. Adults are more common offshore, in deep waters (> 50 m), especially off the coast between East London and Coffee Bay, throughout the year. P. rupestris were found to be rudimentary hermaphrodites. The development of the functional sexes, and the occurrence of sexual dichromatism, are described. Sexual maturity is attained at about 575 mm fork length in those fishes in the spawning areas. Reproductively ripe fishes were taken from Transkei, East London and a small collection was made from the Agulhas Bank. Peak spawning is between August and October. Current management regulations are discussed and advantages of large marine reserves in conservation of this mobile apex predator are outlined.     

Has Sarcocystis neurona Dubey et al., 1991 (Sporozoa: Apicomplexa: Sarcocystidae) cospeciated with its intermediate hosts?

The question of how Sarcocystis neurona is able to overcome species barrier and adapt to new hosts is central to the understanding of both the evolutionary origin of S. neurona and the prediction of its field host range. Therefore, it is worth reviewing current knowledge on S. neurona host specificity. The available host range data for S. neurona are discussed in relation to a subject of evolutionary importance—specialist or generalist and its implications to understand the strategies of host adaptation. Current evidences demonstrate that a wide range of hosts exists for S. neurona. This parasite tends to be highly specific for its definitive host but much less so for its intermediate host (I.H.). The unique specificity of S. neurona for its definitive host may be mediated by a probable long coevolutionary relationship of the parasite and carnivores in a restricted ecological niche ‘New World’. This might be taken as evidence that carnivores are the ‘original’ host group for S. neurona. Rather, the capacity of S. neurona to exploit an unusually large number of I.H. species probably indicates that S. neurona maintains non-specificity to its I.H. as an adaptive response to insure the survival of the parasite in areas in which the ‘preferred’ host is not available. This review concludes with the view that adaptation of S. neurona to a new host is a complex interplay that involves a large number of determinants.     

Influence of the thermocline on the vertical migration of medusae during a 48 h sampling period

The vertical distribution and migratory movements of epiplanktonlc medusae were studied at an oceanic station off northern Namibia (18°00’S /10°30’E). Samples were collected from five separate depth strata (200–100 m, 100–60 m, 60–40 m, 40–20 m, and 20–0 m) using a multiple opening and closing RMT 1 x 6 net over a 48–h period. The area was characterized by mixing of the Angola Current surface waters with the northernmost subsurface waters of the Benguela Current. During the sampling period there was a continuous flow of water from Angola, giving rise to a strong thermocline between 20 and 40 m depth. A total of 17 species of medusae were captured, of which Aglaura hemistoma, Liriope tetraphylla, and Solmundella bitentaculata were the most abundant. Both the number of species and the number of individuals were higher on the second than on the first day of sampling, chiefly in the 20–0 stratum. Differences in abundance appeared to be related to the patch size of each species. The depth diistributlon of the medusae population was characterized by the existence of two assemblages, one associated with each current, and by the presence of the thermocline, which acted as a boundary between the two water masses and did not facilitate migratory movements of the most abundant species. The non-migratory distribution pattern of most of the species was attributable to the high concentration of potential prey items and to the absence of predators in the layer above the thermocline throughout the sampling period.     

Validation of the periodicity of growth zone formation in the otoliths of four fish species from the Upper Zambezi ecoregion,southern Africa

In the Upper Zambezi and Okavango ecoregions, Brycinus lateralis, Hepsetus cuvieri, Schilbe intermedius and Serranochromis macrocephalus are important in subsistence fisheries, while S. intermedius and S. macrocephalus are often caught in commercial catches. Despite their importance, there is little information on their age and growth and age validation. Growth zone deposition rate in otoliths of B. lateralis, H. cuvieri, S. intermedius and S. macrocephalus was validated as annual using edge analysis in this study. Annual deposition of growth zones was corroborated by a fluorochrome marking experiment. Both methods demonstrated that one growth zone was deposited annually. Edge analysis demonstrated that the highest proportion of opaque zones was detected between August and December, most likely as a result of slow growth during lower temperature water during the preceding winter. With growth zone deposition validated as annual, future research should focus on determining the growth, maturity and mortality rates of these species, parameters which are important for their management.     

Diet of the blue petrel at sub-Antarctic Marion Island

Food samples were collected from 49 blue petrels Halobaena caerulea at Marion Island in the sub-Antarctic region. These were analysed and the results compared with previously published data collected at other islands. Crustaceans formed the major prey by mass (59,5%) and frequency (100%), with Euphausia vallentini being of particular importance (56,6% by mass of Crustacea). Other prey included fish, cephalopods and two species of insects, a moth (Noctuidae) and an assassin bug Nabis.     

Rearing unit-level factors associated with bacterial gill disease treatment in two Ontario, Canada government salmonid hatcheries

Early-rearing salmonids in Ontario Ministry of Natural Resources (OMNR) fish hatcheries have been consistently affected by bacterial gill disease (BGD) (causative agent: Flavobacterium branchiophilum) for many years. Separate retrospective epidemiological investigations of BGD treatments at two OMNR fish hatcheries (Hatcheries A and B) for the 1999 production year were conducted using on-site hatchery records. Both investigations were carried out at the rearing unit-level, with early-rearing (<9 months of age) “tank-lot” as the unit of analysis to identify unique fish populations over time. Multivariable repeated measures logistic regression models were created for both hatchery datasets, controlling for lot-level and species effects. For Hatchery A, the species brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) were significantly associated with BGD treatment, as well as lower water exchange rate, and higher feeding and mortality percentages during the 2 weeks previous to BGD treatment. At Hatchery B, the species brook trout (S. fontinalis) and splake (Salvelinus namaycush × S. fontinalis) were significantly associated with BGD treatment, as well as lower individual fish weights and treatment for BGD during the previous week. These results emphasize the importance of water quality, feeding rate, fish size and prior mortality on the development of BGD. Significant hatchery and species effects were evident, and future observational research on BGD must account for these factors in their design and analysis.     

Temporal trends in Giardia occurrence in the Grand River and surrounding tributaries,Waterloo, Ontario (2005–2013), a retrospective analysis of surveillance data

Giardia contamination in the Grand River Watershed (south‐western Ontario, Canada) was monitored from 2005 to 2013 as part of FoodNet Canada. Our study objectives were to describe the temporal pattern of Giardia occurrence and determine whether water quality parameters and bacterial indicators could act as effective markers for Giardia occurrence. Water samples were collected monthly from the Grand River near a drinking water intake point (2005–2013) and also collected intermittently from other areas in the watershed during the study period. Samples were tested for Giardia cysts using the US EPA method 1623. Samples were also tested for chemical and microbial water quality indicators. Univariable and multivariable linear regression models were built to examine whether temporal, water quality and bacterial indicators were associated with Giardia cyst concentration. Giardia cysts were identified in 89% of samples (n = 228), with highest measured concentrations downstream of a waste water treatment plant outfall. Year and season were found to be predictors for Giardia occurrence. Concentrations were significantly higher in the winter and fall compared to the summer, and significantly higher in 2007 compared to other study years. After controlling for season, year and sampling location, dissolved oxygen was the only variable significantly associated with Giardia cyst concentration. Seasonal peaks in Giardia cyst concentrations in samples collected near the intake for the drinking water plant did not align with the seasonal peak in human Giardiasis cases in this region that are reported annually by public health authorities. This suggests that the risk of contracting Giardiasis from treated drinking water in this community is possibly low when the treatment plant is functioning adequately. Instead, waterborne exposure is likely the result of seasonal behaviours surrounding recreational water use. Therefore, the collective findings of our study are important to help inform future risk management studies and guide public health protection policies.     

Biology of Larks (Aves: Alaudidae) in the Central Namib Desert

1. The biology of six species of larks in the Namib Desert near Walvis Bay, South West Africa, was studied in 1964, 1965 and 1966.

2. All species reproduced following rainfall in summer and autumn months, with the appearance of green grass and abundant insects on which the birds fed.

3. The primarily insectivorous species, Certhilauda albofasciata, shows no seasonality in moulting and testicular development, and reproduces whenever local rainfall results in favourable feeding and nesting circumstances, while the primarily granivorous Spizoeorys starki and Eremopterix verticalis have markedly seasonal testicular and moulting cycles timed so that reproduction occurs only during the late summer and autumn months. Ammomanes grayi is intermediate in food habits and in timing of moulting and reproduction, and C. albescens and Mirafra naevia may also be intermediate in this respect.

4. S. starki and E. verticalis are the only larks that normally drink, but flocks of both species were observed that were independent of drinking water.

5. Larks avoid heat stress during daytime by keeping to the shade of stones, tufts of vegetation and mouths of rodent burrows; and nests are nearly always placed on the shady side of a stone' or tuft of grass.

6. It is suggested that larks may be successful desert occupants because they have not become highly specialized and therefore can tolerate rapidly and severely changing environ-mental conditions associated with drought and irregular rainfall.     

Korttermyn invloed van strawwe droogte op veldtoestand en waterverbruiksdoeltreffendheid van grasveld in die sentrale Oranje‐Vrystaat

Short‐term effect of severe drought on veld condition and water use efficiency of grassveld in the central Orange Free State. The impact of an intensive drought (1982/1983 and 1983/84‐growing seasons) on botanical composition, basal cover, mortality of grazing plants and water use efficiency (WUE) of veld in good, moderate and poor condition was identified. Increaser II species were apparently more capable of surviving drought than the Decreaser species. Under optimal soil moisture conditions the Decreaser species increased and the Increaser II species decreased. During the drought extensive grass mortality took place. Veld condition plays an important role in determining mortality during drought. Decreaser species have a high water requirement for optimal WUE, while Increaser II species can reach maximum WUE with less water. Under water stress conditions Increaser II species significantly (P≤0.01) do not use the water as efficiently as do Decreaser species. The WUE under water stress conditions for veld in good, moderate and poor condition was on average, during the study period, 0.90; 0.90 and 0.40 kg ha^?1 mm^?1, respectively, and towards under optimal water conditions, 2.47; 1.67 and 0.23 kg ha^?1 mm^?1, respectively.     

The distribution pattern of Sarcocystis species,their transmission and pathogenesis in sheep in Fars Province of Iran

Of 1362 sheep examined during two years in Fars Province of Iran, 786 (57.7%) were positive for Sarcocystis spp. The prevalence was significantly higher (p<0.05) in animals owned by nomadic Assyrians (67.95%) than in those owned by local people (41.86%). More of the animals above 2 years age were infected (69.98%) than young ones (30.02%). Females had a higher prevalence of infection (61.07%) than males (38.93%) but most of the males were younger. There was no variation in the infection rate during spring, summer or autumn, but it was low in winter. The species observed were Sarcocystis gigantea, predominantly in oesophagus, S. medusiformis, mainly in diaphragm, S. tenella in the oesophagus, diaphragm, tongue and heart, and S. arieticanis in the oesophagus, tongue and occasionally in the diaphragm. In transmission studies, the prepatent period for S. gigantea and S. medusiformis and for the two microscopic species was 11–13, 10 and 8–12 days, respectively. The infection could not be transmitted to hamsters and guinea-pigs. The macroscopic species were almost non-pathogenic but were responsible for economic losses because of rejection of carcases or parts thereof at slaughter. The microscopic species caused tissue damage to the affected organs, resulting in haemorrhages, mononuclear infiltration and necrotic changes.Abbreviations DPI days post infection     

Trial by fire: social spider colony demographics in periodically burned grassland

Nature conservation authorities in southern Africa burn the grassland in nature reserves to reduce the incursion of woody plants and to encourage the growth of new grass for grazing. Studies have shown significant negative effects of burning on the abundance, species diversity and community composition of smaller vertebrates and invertebrates. Social arthropods are likely to suffer from repeated burning, as destruction of the colony means a permanent loss of the entire reproductive unit. Nests of social spiders of the genus Stegodyphus (Eresidae) are a prominent feature of African savannas and their size and visibility make them potentially good indicators of ecological consequences of fire. The colonies are sedentary and their nests may persist for several years, although individuals have an annual life cycle. We explored the mortality patterns and the effects of burning on survival of colonies of two species of social spider, Stegodyphus mimosarum and S. dumicola that live sympatrically. We compared colony mortality in burned and unburned areas to determine if colony mortality was due to burning or, alternatively, to natural senescence. Analysis of five years of nest mortality data together with information on the burning regime in Spioenkop Nature Reserve, KwaZulu Natal province (South Africa), indicates that colony extinction in S. mimosarum is independent of the burning regime, while burning is a significant cause of colony mortality in S. dumicola. The different responses of the two species are likely a result of different colony dynamics and nesting sites.     

Antimicrobial resistance of Staphylococcus pseudintermedius

Staphylococcus pseudintermedius, Staphylococcus intermedius and Staphylococcus delphini together comprise the S. intermedius group (SIG). Within the SIG, S. pseudintermedius represents the major pathogenic species and is involved in a wide variety of infections, mainly in dogs, but to a lesser degree also in other animal species and humans. Antimicrobial agents are commonly applied to control S. pseudintermedius infections; however, during recent years S. pseudintermedius isolates have been identified that are meticillin‐resistant and have also proved to be resistant to most of the antimicrobial agents approved for veterinary applications. This review deals with the genetic basis of antimicrobial resistance properties in S. pseudintermedius and other SIG members. A summary of the known resistance genes and their association with mobile genetic elements is given, as well as an update of the known resistance‐mediating mutations. These data show that, in contrast to other staphylococcal species, S. pseudintermedius seems to prefer transposon‐borne resistance genes, which are then incorporated into the chromosomal DNA, over plasmid‐located resistance genes.     

Adaptation of a decreaser and an increaser grass species to defoliation in semi‐arid grassveld

Abstract

Grasses have developed through natural selection to deter, escape and tolerate herbivory, and to escape and tolerate fire. In the semi‐arid grassveld of the Eastern Cape, the species Themeda triandra and Sporobolus fimbriatus have been classified as Decreaser and Increaser II plants respectively. Both species have well‐developed escape and tolerance mechanisms, although T. triandra readily tolerates defoliation only during the dormant season, while S. fimbriatus is adapted to tolerating defoliation throughout the year. Furthermore, T. triandra has only moderately developed deterrents to herbivory, in contrast to S. fimbriatus, where deterrents are well developed. It follows that the Decreaser species T. triandra is adapted to relatively frequent fire and no more than modest herbivory, while the Increaser II species, S. fimbriatus, is adapted to heavy herbivore usage, but infrequent fire.     

Uterus duplex bicollis,Vagina simplex in laboratory Guinea pigs (Cavia porcellus), rats (Rattus norvegicus forma domestica) and mice (Mus musculus forma domestica)

The female genital tract originates from the Müllerian ducts during embryological development. Fusion of the ducts occurs in different segments depending on the animal species, resulting in a variational number of the respective organ. Current literature on genital tract morphology of laboratory rodents is controversial. Therefore, the present study aimed at determining an anatomically correct definition of the uterus in laboratory guinea pigs, mice and rats. In all three rodent species, we found two separate cervical canals that communicate with an individual uterus via discrete ostia uteri interna. The correct anatomical definition should therefore be uterus duplex bicollis, vagina simplex.     

A Preliminary investigation of the bioenergetics of pregnancy and lactation of Praomys natalensis and Saccostomus campestris

The energy requirements of pregnant, lactating and non-reproductive Praomys natatensis and Saccostomus campestris were studied in metabolism cages and respirometers. Ingestion rate during pregnancy and lactation was not increased significantly in either species. P. natatensis and S. campestris showed non-significant increases in respiratory rate during pregnancy (18% and 55% respectively) but significant increases in oxygen consumption during lactation (79% and 110% respectively). The results highlight the need for studies quantifying lipid and protein flux during pregnancy and lactation, since quantifying energy turnover alone is inadequate and misleading. The energetic costs of reproduction are discussed in relation to previous studies.     

Evaluation of reproductive parameters in male Neotropical bats during dry and rainy months in a specific area of the Cerrado biome

The aim of this study was to analyse the reproductive aspects of male bats of three common species of the Phyllostomidae family: Artibeus lituratus, Platyrrhinus lineatus and Sturnira lilium, during dry and rainy months in a specific area of the Cerrado biome. Body weight was significantly higher during the dry months for S. lilium. The gonadosomatic index (GSI) and testicular weight were not significantly different between dry and rainy periods. The tubular parameters were significantly bigger in A. lituratus than in the other two species during both periods. No difference in the tubular/interstitial ratio was observed in any of the species during both periods. In both periods, all sperm cells and germ cell developmental stages were visible on seminiferous tubules whereas sperm cells were observed in epididymides of all sampled animals. The percentage of morphologically normal sperm was low (35%–60%), with no difference between periods. Spermatozoa from A. lituratus presented a leaf-shaped head, while the head was round-shaped in the other two species. In conclusion, our data suggest that males from the three studied species did not present reproductive latency during the most critical weather periods (dry and rainy months) in the metropolitan region of Brasilia, Brazil.     

Arcobacter: an emerging food-borne zoonotic pathogen,its public health concerns and advances in diagnosis and control – a comprehensive review

Arcobacter has emerged as an important food-borne zoonotic pathogen, causing sometimes serious infections in humans and animals. Newer species of Arcobacter are being incessantly emerging (presently 25 species have been identified) with novel information on the evolutionary mechanisms and genetic diversity among different Arcobacter species. These have been reported from chickens, domestic animals (cattle, pigs, sheep, horses, dogs), reptiles (lizards, snakes and chelonians), meat (poultry, pork, goat, lamb, beef, rabbit), vegetables and from humans in different countries. Arcobacters are implicated as causative agents of diarrhea, mastitis and abortion in animals, while causing bacteremia, endocarditis, peritonitis, gastroenteritis and diarrhea in humans. Three species including A. butzleri, A. cryaerophilus and A. skirrowii are predominantly associated with clinical conditions. Arcobacters are primarily transmitted through contaminated food and water sources. Identification of Arcobacter by biochemical tests is difficult and isolation remains the gold standard method. Current diagnostic advances have provided various molecular methods for efficient detection and differentiation of the Arcobacters at genus and species level. To overcome the emerging antibiotic resistance problem there is an essential need to explore the potential of novel and alternative therapies. Strengthening of the diagnostic aspects is also suggested as in most cases Arcobacters goes unnoticed and hence the exact epidemiological status remains uncertain. This review updates the current knowledge and many aspects of this important food-borne pathogen, namely etiology, evolution and emergence, genetic diversity, epidemiology, the disease in animals and humans, public health concerns, and advances in its diagnosis, prevention and control.     

Ranking of grass species according to visible wilting order and rate of recovery in the central orange free state

Abstract

A number of grasses were ranked according to the order in which they wilted with diminishing moisture availability, and according to their ability to recover after water replenishment. Digitaria eriantha and Digitaria argyrograpta were the most sensitive to moisture stress, whereas Sporobolus fimbriatus and Panicum stapfianum were last to show signs of wilting. The latter two grass species were the first to recover from wilting during optimum soil water conditions. The leaf water potential and soil water content at which each grass species wilted were recorded.     

Body Lengths and Temperatures of the Crabeater Seal

In arid or semi-arid areas of southern Africa, frogs are typically active nocturnally and seasonally. They may adopt a variety of strategies to conserve water during the day or during the unfavourable part of the year. Aquatic frogs (e.g. Xenopus, most species of Sana, Ptychadena and Phrynobatrachus) do not normally have a water conservation problem except when the water in or near which they are living dries up. Burrowing frogs (e.g. Bufo, Pyxicephalus, Tomoptema and Breviceps) are able to select microhabitats in the soil which reduce evaporative water loss. Burrowing may, in particular cases, be associated with the formation of a keratinized cocoon of stratum corneum which appears to offer a barrier to outward water movement. In arboreal frogs (Chiromantis xerampelina and Hyperolius spp.) the most interesting adaptations are found. Evidence is given in the case of HyperoUus nasutus for low evaporative water losses at the end of the dry season, when the frogs sit exposed to the sun and dry air, in flowers. During the rains when H. nasutus is in breeding aggregation the evaporative water losses are high. Chiromantis xerampelina is uricotelic and resistant to desiccation.

The three approaches which anurans have adopted in response to water conservation problems have their correlates in bladder size and function. hormonal regulation of water balance and the extent to which water loss can be tolerated. The potential that the southern African amphibian fauna offers for physiological research is emphasized.