The decrease in seed germination ofStriga hermonthica in Benin in the course of the rainy season is due to a dying-off process

Germination rate and viability ofStriga hermonthica seeds in the field in the Republic of Benin decreased steadily in the course of the rainy season. The percentage of germinating seeds decreased from 82% on April 13, 1993 to 16% on October 13, 1993. The percentage of viable seeds, according to the tetrazolium colour test, decreased in the same period from 90% to 15%. In the subsequent rainy season these values further decreased and it was concluded that the seeds do not enter a stage of secondary dormancy. This implies that if host plants (including wild hosts) are consistently kept away from infested fields for one or two year periods, this will lead to a dramatic decrease in the number of viableS. hermonthica seeds in the soil.     

Composition,characteristics and long-term variability of the freshwater microcrustacean fauna of the Faroe Islands

ABSTRACT

Despite the accessibility of the Faroe Islands, faunistic research on their numerous lakes and ponds is quite rare. The biota of Faroese freshwaters is still underexplored, and its specific traits raise many questions. In the present survey, 32 microcrustacean species were observed, 8 of which were new to the Faroese fauna. The obtained species list shows that Cladocera species prevail over Copepoda here, which is not typical of northern territories. This fact is due to (1) the extraordinarily warm climate of the Faroe Islands compared to other areas at similar latitudes because of the heating effect of the surrounding North Atlantic Current and (2) the lack of calanoid species, which have never been found in the freshwaters of the Faroe Islands. The diachronic analysis of the species diversity and composition over the centuries of research on the archipelago showed no evidence of the impact of global climate change on the fauna.     

The freshwater crustaceans (Cladocera: Copepoda) of Bering Island (Commander Islands,Russian Far East): species richness and taxocene structure

The crustaceans of the fresh waters of Bering Island and their link to the fauna of adjacent regions were studied. Based on original data and existing literature, the species composition of Cladocera and Copepoda was described. The compiled list includes 22 species of Cladocera and 30 species of Copepoda. In the original data, 35 species native to the Commander Islands were reported for the first time. Six species were newly reported in the Far East, and two were newly reported in Russia. The ecological peculiarities of several species and some biogeographical features of the freshwater zooplankton of the island are discussed. The main part of the fauna of the island form Holarctic widespread species (64.3%), another slightly smaller group of the fauna is comprised of Palaearctic species (20.1%), and the remainder comprise Nearctic (6.7%) and Beringian species (8.9%). Particular patterns in the distribution of freshwater zooplankton and the factors underlying the occurrence of these species on the island are considered.     

A new species of the dentipes-subgroup of Triconia and a redescription of T. giesbrechti and T. elongata (Copepoda: Cyclopoida: Oncaeidae) from the tropical Pacific and the Korea Strait

A new species of Triconia in the family Oncaeidae, Triconia pacifica sp. nov., and a new form variant each of Triconia giesbrechti Böttger-Schnack and Triconia elongata Böttger-Schnack are described from two sites in the Pacific. Triconia pacifica can be distinguished from its sibling Triconia dentipes (Giesbrecht) by (1) morphometric characters, including the proportional lengths of distal endopod spines of swimming leg 4, and the relative length of the outer basal seta on P5, and by (2) a number of micro-structures on the appendages. The Pacific specimens of T. elongata and T. giesbrechti resemble the typical forms in morphometric characters, with some minor differences in proportional spine lengths on the swimming legs, and differ in a few micro-structures. The hitherto unknown male of T. giesbrechti is newly described. For all species/forms described, the intraspecific variability of proportional spine lengths on the endopods of P2–P4 is examined and discussed. http://www.zoobank.org/urn:lsid:zoobank.org:pub:6B41B0E2-0A5C-458B-8F9C-25000F208E24     

New family and genus Rostrocalanus gen. nov. (Crustacea: Calanoida: Rostrocalanidae fam. nov.) from deep Atlantic waters

Two new species of a new genus and family Rostrocalanidae of benthopelagic clausocalanoid copepods are described from female specimens collected from abyssal depths close to the sea bed in the tropical Atlantic. Rostrocalanus gen. nov. shares the presence of sensory setae on maxilla with other bradfordian families of Clausocalanoidea, but does not fit the diagnosis of any of these families. A family Rostrocalanidae is established for this new genus and is defined by the following derived characters: four‐segmented exopod of mandible supplied with four setae; distal basal endite of maxillule fused to endopod and bearing five setae in total; endopod of maxilla furnished with six worm‐like sensory setae; arrangement of setal numbers on praecoxal endites of maxilliped syncoxa as 0, 1, 2. The establishment of a new clausocalanoidean family sheds new light on the morphological diversity of bradfordian benthopelagic copepods and adds to the biodiversity of the deep‐water calanoid fauna.     

X.—New Hymenoptera of the family Bethylidæ

What seems likely to be the first published record of a foraminiferan protozoan (Cibicides lobatulus) epizoic on an isopod (Astacilla longicornis) is reported from material collected by divers off the Berwickshire coast (Scotland). Notes are also provided on other epibionts and a comparison is made with Astacilla from the Clyde Sea area which proved to have a much lower incidence of fouling. There, fouling was due largely to the entroproct Barentsia sp. and the hydroid Clytia hemisphaerica, not to Cibicides.     

Harpacticoid copepods (Thalestridae) infesting the cultivated Wakame (brown alga,Undaria pinnatifida) in Korea

Two species of thalestrid harpacticoid: Amenophia orientalis n. sp. and Parathalestris infestus n. sp., are described based on specimens collected from Soando Island in Korea. These copepods infest the cultivated brown alga, Wakame, Undaria pinnatifida (Harvey), producing galls with pinholes (0·5–1·1.5 mm in diameter) on the fronds, midribs, and sporophylls. A. orientalis outnumbered P. infestus in all of the observed incidences; however, the fecundity of the latter species is twice that of the former.     

Chondracanthid copepods parasitic on flatfishes of Kerala,India

Eight species of chondracanthid copepods (Poecilostomatoida) were recovered from nine species of flatfishes collected in Kerala, India. They are: Acanthochondria zebriae sp. nov. from Zebrias synaturoides; Bactrochondria papilla gen. et sp. nov. from Cynoglossus dubius; B. hoi (Pillai, 1985) from C. lida; Heterochondria pillai Ho, 1970 from C. lida, Pseudorhombus arsius, P. elevatus, P. javanicus and P. triocellatus; H. petila sp. nov. from P. arsius, P. javanicus and P. triocellatus; H. similis (Yu and Wu, 1932) from C. azureus; and both Protochondracanthus alatus (Heller, 1868) and P. trilobatus (Pillai, 1964) from Psettodes erumi.     

TEM observations on symbionts of Joenia annectens (Flagellata Hypermastigida)

Transmission electron microscopy was used to evaluate the ultrastructural morphology of some other symbiotic prokaryotes of Joenia annectens, an intestinal flagellate of the termite Kalotermes flavicollis. Three morphotypes are predominant and recognizable from their morphological characteristics. One morphotype is represented by spirochaetes that are mainly external and cover the flagellate, helping its movement. Rod-shaped bacteria, which represent the second morphotype, are also attached to the surface among the spirochaetes. Rod-shaped bacteria and some spirochaetes may enter the cell surface of Joenia annectens as a consequence of phagocytosis, remaining enclosed in an envelope of plasma membrane. A nutritive role of rod-shaped bacteria in this symbiotic association is suggested. A third, different morphotype of prokaryotes is represented by roundish microorganisms which, gathered together with other cytoplasmic organules, form a large collar, encircling the axostyle; their function is still unknown.