Pseudanthocotyloides heterocotyle (van Beneden, 1871) Euzet & Prost, 1969 (Monogenea: Polyopisthocotylea: Mazocraeidae), a parasite of herring Clupea harengus L. and sprat Sprattus sprattus L. (Teleostei: Clupeidae)

A total of 690 herring Clupea harengus L. and 88 sprat Sprattus sprattus L. caught off the west coast of Sweden, in the North Sea and off the west and south coasts of the United Kingdom, were examined for gill parasites. The monogenean Pseudanthocotyloides heterocotyle (van Beneden, 1871) Euzet & Prost, 1969 was found in 38 (5.5%) herring and one (1.1%) sprat. The parasite was significantly (P>0.05) more common off the west coast of Sweden than elsewhere and most specimens (62.5%) were found on the pseudobranchs. Only the smaller herring were infected. P. heterocotyle is redescribed and its taxonomy discussed, together with the possibility of host and parasite misidentification in previous reports.     

Two new species of Polygala (Polygalaceae) from Somalia

The new species Polygala praetermissa , a dwarf perennial herb growing in stony places on limestone, and P. dasanensis , a shrublet apparently confined to gypsum, are described. Both species occur in the Cal Miskaat Range in north-eastern Somalia, but P. praetermissa has a wider distribution in northern Somalia.     

Indications for operation in suspected appendicitis and incidence of perforation.

OBJECTIVE--To clarify poorly understood epidemiological features of appendicitis. DESIGN--Retrospective study of consecutive cases from a defined population and analysis of data from published studies. SETTING--County of Jönköping, Sweden. 3029 patients who underwent operation in 1984-9 and 4717 patients from the county town who underwent operation in 1970-89, all for suspected appendicitis, plus 48,426 cases from six reported studies. MAIN OUTCOME MEASURES--Incidences specific for age and sex and temporal trends of perforating and non-perforating appendicitis and removal of a normal appendix. Associations between diagnostic accuracy, rate of perforation, and incidences of removal of a normal appendix and of perforating and non-perforating appendicitis. RESULTS--The incidence of appendicitis was 116/100,000 inhabitants. Appendicitis was more common in male patients. The incidence of perforating appendicitis was independent of age, stable over time, and uninfluenced by the rate of laparotomy, whereas the incidence of non-perforating appendicitis was age dependent, decreasing over time, and related to the diagnostic accuracy and rate of removal of a normal appendix. CONCLUSIONS--Perforating and non-perforating appendicitis seem to be separate entities, and appendicitis that resolves spontaneously is common. This may have important implications for managing suspected appendicitis.     

Highly variable microsatellite loci for studies of introduced populations of the small Indian mongoose (Herpestes javanicus)

During their introduction, non‐native species typically undergo founder events that reduce genetic variation. To allow a high‐resolution genetic investigation of introduced populations of the small Indian mongoose (Herpestes javanicus), we developed primers for nine variable microsatellite loci. Their applicability was assessed in 10 mongooses from the large Fijian population, which originated from a single pair from Calcutta, India. The number of alleles ranged from two to five per locus, possibly as a result of preservation of initial variability and in situ mutations during the rapid population expansion after introduction.     

Bourreria (Boraginaceae) in tropical Africa

Five species of Ehretia in eastern Africa are shown to be better placed in the currently entirely American genus Bourreria . The new species B. lyciacea from S Somalia and E Kenya is described and illustrated. New combinations are B. petiolaris, B. nemoralis, B. orbicularis and B. teitensis .     

The epidemiology of the metacercariae of Diplostomum baeri and D. spathaceum in perch (Perca fluviatilis) from the warm water effluent of a nuclear power station

Thermal effects on the dynamics of infection with metacercariae of Diplostomum baeri and D. spathaceum were monitored between May and September, in a year-class of perch Perca fluviatilis, in an artificial lake receiving warm water discharges from a nuclear power station and in an unheated reference site, for a two year period. In the heated area the prevalence of infection of the retinal form, D. baeri, was always 100%, whereas in the unheated site there was an increase from 93% in May to 100% in June 1986. The relative density of D. baeri was found to increase gradually during the first summer in both areas, although the accumulation rate of metacercariae was significantly increased in the heated area. In August of the first year the relative density of D. baeri peaked in the heated area, whereas it continued to increase in the unheated control. However, in September of the following year, the relative densities were at the same level in both thermal regimes. A concomitant decline in the degree of overdispersion of metacercariae within the host population was observed in the heated area as the population density of metacercariae decreased, whereas the index of dispersion remained at the same level throughout the study in the unheated area. However, it was not possible to sample perch in the unheated area between October 1986 and May 1987 and changes in the parasite population could have occurred during this period. The prevalence and relative density of D. spathaceum, the lens form, was on the contrary low, especially in the unheated site where it was recorded only occasionally. The infection of D. baeri exhibited a convex pattern in both thermal regimens, although the peak infection was noticed earlier in the heated area. Regulation of the parasite infrapopulation may have been achieved by the combined effects of a decreased transmission rate of cercariae with increasing age of the host, the mortality of metacercariae as a natural termination of the life span and to selective predation of heavily infected hosts. However, regardless of an increased accumulation rate of metacercariae in the heated area, the relative densities of D. baeri became equal in both thermal regimes at the end of the study. The mortality rate of metacercariae in the heated area was therefore presumably increased as compared with the unheated reference site.     

Synopsis of Hyacinthaceae in tropical East and North-East Africa

Nine genera of Hyacinthaceae, Albuca, Bowiea, Dipcadi, Drimia, Drimiopsis, Lede-bouria, Ornithogalum, Schizobasis and Scilla , with a total of 34 species, are recognized in Ethiopia, Somalia, Djibouti, Uganda, Kenya and Tanzania. One new species, Ledebouria urceolata , is described from Ethiopia. New combinations are Drimia simensis, Drimiopsis fischeri, Ledebouria sornaliensis, L. kirkii, L. edulis and L. cordifolia . Several names are reduced to synonymy and some are lectotypified. Keys to all taxa are given.     

A new species and a new record of Tephrosia (Leguminosae) from Socotra

Tephrosia socotrana sp. nov., a woody species growing on limestone cliffs in north-central Socotra (Yemen), is described and illustrated. strigosa is recorded from Socotra and Yemen for the first time.     

Detecting hybridization between willow grouse (<Emphasis Type=Italic>Lagopus lagopus</Emphasis>) and rock ptarmigan (<Emphasis Type=Italic>L. muta</Emphasis>) in Central Sweden through Bayesian admixture analyses and mtDNA screening

Willow grouse (L. lagopus) and rock ptarmigan (L. muta) are sibling species with similar phenotypic and life histories that coexist sympatrically in wide areas of their distribution range. These grouse are amongst the most popular game birds in Scandinavia but contrary to other quarry species, no restocking with captive-bred animals has ever been performed. The discovery of two individuals with intermediate plumage features evoked the question of possible hybridization events between both species, an idea that did not seem too unlikely on the basis of habitat overlap. Thus, to assess whether any genetic exchange is occurring, we used different Bayesian-based admixture analyses of multilocus genotypes determined at twelve microsatellite loci. We also obtained mitochondrial COI-sequences from a selected number of individuals to infer the maternal geneflow and potential introgression. The capacity of our panel of microsatellite markers to detect hybridization was verified using assignments of simulated genotypes. We then evaluated the extent of hybridization in an actual sample of 111 individuals collected in a 100-km² area in the Scandinavian mountain range. An admixed condition was verified in one of the suspected hybrids, that seemed to carry a L. muta genotype with partial L. lagopus introgression. In addition, more than 4% of L. lagopus showed signs of hybridization under the most conservative scenario with respect to discrepancies between population assignment methods. This was unexpected, given that no L. lagopus displayed any apparent intermediate plumage features. Furthermore, interspecific geneflow of mtDNA haplotypes was lower than expected; which suggests that Haldane’s rule might apply for these two grouse species. Hence, plumage identification of hybrid ancestry is not always reliable and might lead to biases in the estimation of hybridization rates. Hybridisation may be expected to increase if the climate gets warmer as the habitat overlap between the species will become more extensive. We discuss whether hybridisation is a threat to the long-term survival of any of the two species.