Food and feeding of three Citharinus species in Lake Kainji, Nigeria

This paper provides information on the food and feeding habits of three Citharinus species in Lake Kainji. A total number of 2357 specimens made up of 1628 Citharinus citharus , 705 C. distichodoides and 24 C, latus were examined. The majority of the fish caught by gill-netting had empty stomachs unlike those caught by cast-netting and electrofishing. The main food items were planktonic and epipelic blue-green and green algae. All the three species had similar feeding habits and also fed on the same items; their food varied with the seasons. Citharinus spp. have high gut length/standard length ratios which are adaptations to the microphagous and planktivorous feeding habits.     

Aspects of the reproductive biology of Hippopotamyms pictus from Lake Kainji, with notes on four other mormyrid species

A method is described for the assessment of fecundity in mormyrid fish. In all species examined a tri-modal egg size distribution was found in the mature pre-spawning ovary. These modes represented one oocyte and two ova components. The significance of the presence of two sizes of ovum is discussed in relation to breeding periodicity in Hippopotamyrus pictus . Size and age at first maturity are estimated for this species. The probable effects of the formation of the lake on the breeding behaviour of mormyrids is discussed.     

The food of adult copepods from Lake Kainji, Nigeria

SUMMARY. Gut contents of adult copepods from Lake Kainji were analysed. The calanoid copepod Tropodiaptomus banforanus was exclusively herbivorous with Melosira and Peridinium forming a large proportion of the diet. Of the cyclopoid copepods, Mesocyclops leuckarti was mainly carnivorous while the smaller Thermocyclops neglectus was mainly herbivorous. Experiments with Diplocystis (Microcystis) showed that it was not ingested by these three copepod species even after starvation and possible explanations for the results are discussed.     

A new genus and species of cypridid ostracod from India, with notes on its biology

A new Recent cypridid ostracod genus Bharatcypris , belonging to the subfamily Cypridinae, with Bharatcypris mackenziei sp. nov. as type-species is described from the Punjab, India. Some observations on its biology are also recorded. Two Indian species previously placed in Sclerocypris are transferred to the new genus.     

SEM observations of some noteworthy diatoms from the Ikpoba reservoir,Nigeria

ABSTRACT

Eighteen taxa of diatoms from the Ikpoba reservoir, southern Nigeria are listed in this report. They belong to the genera Cymbella, Stenopterobia, Eunotia, Brachysira, Frustulia, Navicula, Pinnularia, Stauroneis and Surirella. The occurrences and distribution of the algae are indicated. Two of these taxa occurred very frequently, six frequently and four occasionally. Five taxa had rare occurrences while one was very rare. They were compared with national as well as regional records.     

The reproductive biology of Pellonula afzeliusi Johnels,and Sierrathrissa leonensis thys Audenaerde in Lake Kainji,Nigeria

Aspects of the reproductive biology of the two species of clupeids known to occur in Lake Kainji, Pellonula afzeliusi Johnels and Sierrathrissa leonensis Thys Van Den Audenaerde were studied for a period of twenty eight months. Mature individuals were found in both species all the year round but with a prolonged peak of activity from December to May, more distinct in P. afzeliusi than in S. leonensis.There were no significant length differences between mature males and females in both species. The smallest mature individuals were 28 mm standard length female; 27 mm standard length male in P. afzeliusi, while the corresponding figures for S. leonensis were 18 mm standard length female and 19 mm standard length male.No sexual dimorphism was observed. There was a simple correlation between fecundity and fish standard body length as well as weight in both species.     

Field observations on some dwarf chameleons (Brookesia spp.) from rainforest areas of Madagascar, with description of a new species

Six species of Brookesia dwarf chameleons were recorded during two rainforest expeditions in Madagascar. One of these is described as a new species Brookesia valerieae based on the arrangement of the nine pairs of dorso-lateral spines, the lack of a pelvic shield, and dorsal chevron markings. Observations were made on the defence and roosting behaviours shown by these six species. Aspects concerning the evolution and conservation in Madagascar are discussed for this poorly studied group of endemic Malagasy reptiles.     

Systematic revision of the catfish genusSilurus,with description of a new species from Thailand and Burma

On the basis of external morphology and anatomy, 17 scpeies of the genusSilurus Linnaeus including a new species,S. torrentis from Thailand and Burma, are recognized as valid.S. bedfordi Regan is synonymized withS. asotus, andS. goae Haig is transferred to the genusOmpok. From an anatomical study of 12 species, the diagnostic feature of the genusParasilurus Bleeker is revealed to be invalid, and the genus is synonymized withSilurus. From the phylogenetic analysis, the genusSilurus is divided into two major species groups, thecochinchinensis group which is disributed mainly in Southeast Asia, and theglanis group which is further separated into three subgroups occurring separately in East Asia and Europe. The pattern of distribution and relationships between ontogeny and phytogeny in the genusSilurus are briefly discussed.     

Observations on the biology of nymphs of Povilla Adusta Navas (Ephemeroptera: Polymitarchidae) in Lake Kainji,Nigeria

Observations onPovilla adusta Navas nymphs in Lake Kainji revealed that seasonal fluctuations in abundance were due to a shortage of food during the period of rising lake level rather than a depletion of oxygen in the water column; this shortage was caused by the increased turbidity of the flood waters restricting the growth of both planktonic and periphytic algae. Planktonic algae apparently formed the diet of nymphs <4–6 mm and also of larger nymphs if their preferred diet of periphytic algae was in short supply. Both depth distribution and individual size of the nymphs were closely related to the distribution of periphytic algae. Depth distribution patterns of the nymphs revealed a peak between 2–4 m below the surface.The dimensions of the nymphs and the duration of the aquatic stages (3–4 months) in Lake Kainji correspond closely with results obtained elsewhere as does the mean percentage of males in the population (28%±10%). Seasonal fluctuations in the sex ratio were apparently caused by variations in the intensity of predation.Department of Zoology, University of Reading     

Food and feeding of three Distichodus species (Pisces: Characiformes) in Lake Kainji,Nigeria

The food and feeding of three Distichodus species in Lake Kainji, Nigeria was studied. Sixty 140 and 528 specimens of Distichodus brevipinnis, D. engycephalus and D. rostratus respectively were examined. All three species were exclusively herbivorous. Their feeding was intense in the evening until dusk but declined during the day. All exhibited some seasonal variation in their food preferences.     

Thamnobryum cataractarum,a new species from Yorkshire,with observations on T. angustifolium and T. fernandesii

Abstract

Thamnobryum cataractarum sp. nov. is described from Yorkshire, England. It is most closely related to T. fernandesii from Madeira and is also similar to T. angustifolium from Derbyshire, England. The three species are compared, and the habitat of the new species is described. T. fernandesii and T. cataractarum are retained in Thamnobryum rather than in Crassiphyllum Ochyra.     

Lithoglyptes cornutus,new species (Cirripedia: Acrothoracica), a boring barnacle from the Seychelles,with some data on its ultrastructure

A new species of the Lithoglyptes from the Seychelles is described. The external morphology of the mantle sac and the body were examined under SEM. The position of a new species within Lithoglyptes and the ultrastructural characters of different species of this genus are discussed.     

Hieracium vierhapperi (Asteraceae) a new species to the Carpathians, with some remarks on its origin

Hieracium vierhapperi (Zahn) Szeląg, known so far only from the Alps, was discovered in the Nízke Tatry Mts in Slovakia, as a new species to the Carpathians. Diagnostic characters, illustration and distribution as well as ecology of H. vierhapperi in the Nízke Tatry Mts are given. A key to distinguish H. vierhapperi from the morphologically related species is added. The Carpathian plants are tetraploid (2n = 36) and reproduce apomictically. The origin of H. sect. Cernua R. Uechtr in the Western Carpathians is briefly discussed.     

Distribution of small rodents and shrews in a lowland rain forest zone of Nigeria, with observations on their reproductive biology

This paper describes the habitat preferences of small rodents and shrews from April 1984 to March 1985 in four types of vegetation in a lowland rain forest zone of Nigeria. The vegetation types were high forest, scrub, farmlands and teak plantations in Ogba Forest Reserve, Nigeria. A collection of 359 small mammals, consisting of six species of small rodents and four species of shrews, was made in the study area. The small rodents and their percentage composition were Mus musculoides (26.2%), Praomys tullbergi (16.2%), Mastomys natalensis (7.0%), Lophuromys sikapusi (4.5%), Lemniscomys striatus (2.5%), and Arvicanthis niloticus (1.1%). The shrews were Crocidura nigeriae (19.5%), C. crossei (12.3%), C.grandiceps (7.8%) and C. ftavescens manni (3.1%). The vegetational distribution of the small rodents and shrews is discussed. In the high forest, seven species of small mammals were caught; these were Crocidura nigeriae, C. crossei, C.grandiceps, C.flavescens manni, Mus musculoides, Praomys tullbergi and Lophuromys sikapusi. Mus musculoides, Crocidura nigeriae and Praomys tullbergi were more abundant in the high forest. All the species of small mammals recorded in the study area, except Arvicanthis niloticus, were found in the scrub. In the farmlands, all ten species of small mammals were trapped. Mus musculoides was the commonest species in the farmlands. Three species of shrews, Crocidura crossei, C. grandiceps and C.flavescens manni, and also two species of small rodents, Mus musculoides and Mastomys natalensis were caught in the teak plantation. The reproductive data for Mus musculoides, Crocidura nigeriae and Praomys tullbergi show that breeding in these species occurs throughout most months of the year. Fecundity appears to be maximal in the wet season in Mus musculoides and Crocidura nigeriae and in the dry season in the case of Praomys tullbergi.     

Further observations on the genus Geonemertes with a description of a new species from the Philippine Islands

Intraspecific variation in the histological appearanceof several morphological characters is examined in 33specimens of the land nemertean, Geonemertespelaensis, obtained from many separate geographiclocations. Variations in the external appearance,together with other characters not previously reportedfor this species, are also discussed. A new speciesof Geonemertes from the Philippine Islands, G. philippinensis sp. nov., is described andillustrated, and an emended diagnosis of the genus isprovided.     

The Orthoptera family Cooloolidae, including description of two new species and observations on biology and food preferences

Abstract. The Australian endemic family Cooloolidae is reviewed and two new species, Cooloola ziljan and C.dingo, are described from near Bundaberg and in the Blackdown Tableland, Queensland. Comments are made on the ecology of the three species; laboratory experiments to determine the preferred foods of C.dingo are described -this species appears to be entirely carnivorous. Additional locality records for C.propator Rentz are listed and discussed. A key to species, tables of measurements and lists of distinguishing characters are presented.     

Taxonomic observations on some species of the genusParietaria

Taxonomy and distribution ofParietaria serbica.Pan?,P. lusitanica L.,P. micrantha Lebed. andP. mauritanica Dur. is briefly discussed.P. serbica is an endemic species of SE. Europe and is related toP. judaica Strand in L.P. lusitanica is divided into two subspecies.P. micrantha is treated as a variety ofP. lustitanica subsp.chersonensis (Lang) Chratek.P. mauritanica is reported as a new species for Sicily.     

Review of the green lacewing genus Chrysacanthia Lacroix with a new species from Nigeria (Neuroptera,Chrysopidae)

The genus Chrysacanthia Lacroix (Chrysopidae: Belonopterygini) is reviewed and a new species is described from Nigeria. With the addition of the new species described herein, the genus contains four Old World species known from Madagascar, Nigeria, India, Thailand and China.