The Fossil Record of Shell Boring by Snails

The predatory boring habit common to many recent snails probablyarose first in the Polinicinae (Naticacea) during Upper Cretaceous(Cenomanian) times (100 million years B.P.) . In the fossilrecord the frequency of bored shells increasesgreatly in rocksof latest Cretaceous age and becomes more widespread duringearly Tertiary times coincident with the major diversificationof the primary groups of boring snails. The borings in these Cretaceous and Tertiary shells show thesame characteristics of preference of penetration in one pelecypodvalve rather than the other or in position of the boring siteon the shell that are found in recent shell assemblages. Borings in Paleozoic brachiopod shells (230–550 millionyears old) that have previously been attributed to gastropodpredation are herein attributed to other but unknown boringorganisms. In part these borings are not accepted as evidence of Paleozoicgastropod predation because it necessitates: (1) Postulationof the separate development of a boring habit ith its concomitantdevelopment of an accessory boring organ in a groupwhose descendantsare all herbivores, and (2) The development of such a habithundreds of millions of years before the appearance of any relativesof present day borers.     

Taxonomy of Toxoplasma*

SYNOPSIS. After reviewing reports of the hosts, structure and life cycle of Toxoplasma, the genus is placed in the apicomplexan family Eimeriidae and the following 7 species are recognized: Toxoplasma gondii (Nicolle & Manceaux) (type species) from about 200 species of mammals and birds, with oocysts in felids; Toxoplasma alencari (Da Costa & Pereira) from the frog Leptodactylus ocellatus; Toxoplasma brumpti Coutelen from the iguana Iguana tuberculata; Toxoplasma colubri Tibaldi from the snakes Coluber melanoleucus and Coluber viridiflavus; Toxoplasma hammondi (Frenkel & Dubey) (a new combination for Hammondia hammondi) from the house mouse with oocysts in the domestic cat; Toxoplasma ranae Levine & Nye from the leopard frog Rana pipiens; and Toxoplasma serpai Scorza, Dagert & Iturriza Arocha from the toad Bufo marinus.     

Changes in the crustacean zooplankton community of Harp Lake, Canada, following invasion by Bythotrephes cederstrœmi

1. Detecting the impacts of invading Bythotrephes cederstrœmi (Crustacea, Onychopoda, Cercopagididae) on zooplankton in North American lakes has been hampered by the brevity of pre-invasion data, and by the difficulty of distinguishing the effects of the invader from other stresses. The data from Harp Lake in Ontario, Canada, circumvent these difficulties. Bythotrephes appeared in the lake in 1993. There is a 15-year pre-invasion data set, and no significant complicating concurrent stresses.
2. The species composition and the size structure of the crustacean zooplankton community of Harp Lake changed after the invasion. Several small species either declined dramatically in abundance (e.g. Bosmina longirostris , Tropocyclops extensus ) or disappeared ( Chydorus sphaericus , Diaphanosoma birgei , Bosmina ( Neobosmina ) tubicen ). In contrast the abundance of the larger cladocerans Holopedium gibberum and Daphnia galeata mendotae and the hypolimnetic copepod Leptodiaptomus sicilis increased. Several univariate and all multivariate summarizations of zooplankton abundance, biomass and size structure highlighted the uniqueness of the post-invasion community.
3. The alterations in the zooplankton community could not be attributed to changes in lake acidity, thermal regimes, penetration by ultraviolet light, nutrient status, fish stocking or the abundances of native invertebrate predators, but they were correlated with Bythotrephes abundance, both within and among years. Hence, we hypothesize that the invasion by Bythotrephes has significantly altered the crustacean zooplankton community of Harp Lake.     

The influence of habitat management on the breeding success of the Great Bittern Botaurus stellaris in Britain

Great Bitterns Botaurus stellaris have experienced a population decline in the UK, such that in 1997 the total number of breeding males was just 11. This study aimed to identify factors affecting productivity, and how management could be used to manipulate this. An intensive study of Great Bittern breeding success was conducted between 1997 and 2001. The date that males established their booming territories was closely correlated with when females started nesting. Wetter sites with greater fish densities had males that established their booming territories earlier in the season. However, only the date that males started booming determined when females started nesting. The mean clutch size of Great Bitterns was four and the only cause of nest failure was predation. Of eight nests suspected to be second attempts the mean interval between these first and second attempts was 12.25 ± 0.88 (sd) days (range 8–15). The fate of radiotagged chicks followed to fledging revealed that the overall probability of a chick surviving to fledge was 39.1%. Daily losses of Great Bittern chicks due to starvation/exposure accounted for 76.25% and predation 21.25%. The youngest chicks in poor condition were most likely to die, particularly in periods of high rainfall. A simulated renesting model allowed estimation of Great Bittern productivity as 1.24 chicks per female and 1.52 nesting attempts per female. Habitat management, or lack of water control that resulted in sites being drier in spring, delayed nesting, although statistically there was no difference in productivity compared with wetter sites.     

Mechanism of Kasugamycin Resistance in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Strains of Escherichia coli are resistant to the antibiotic kasugamycin due to the partial non-methylation of 16S ribosomal RNA. An RNA methylase activity, absent from resistant strains, is shown here to methylate in vitro the 16S RNA of resistant as well as sensitive strains.     

A Check-List of the Species of the Genus Leucocytozoon (Apicomplexa,Plasmodiidae)*

SYNOPSIS. A list is given of 67 named species of Leucocytozoon considered valid at present. Another list is given of 1 reptilian and 146 avian hosts of named species of Leucocytozoon. A 3rd list is given of 34 synonyms. Leucocytozoon has been named from about 0.7% of the approximately 8600 species of birds that exist. The following new taxonomic names are included: L. danilewskyi var. hirundinis Sergent & Sergent, 1905 is emended to L. hirundinis; Saurocytozoon tupinambi Lainson & Shaw, 1969 is changed to Leucocytozoon (Saurocytozoon) tupinambi (Lainson & Shaw, 1969).     

A Check-List of the Species of the Genus Haemoproteus (Apicomplexa,Plasmodiidae)*

SYNOPSIS. A list of the presumably valid named species of the genus Haemoproteus Kruse, 1890 (Apicomplexa, Plasmodiidae) is given. It includes 133 species, 5 varieties and 1 subspecies. One new species is named: H. serini n. sp. for the form in the canary Serinus canarius called H. zuenyoni by Sergent & Sergent (90). The following emendations are made: H. aegyptius for H. cellii var. aegyptius Mohammed, 1958; H. cellii for H. noctuae var. cellii Coatney & Roudabush, 1937; H. hirundinis for H. danilewskii var. hirundinis Sergent & Sergent, 1905; H. tinnunculus for H. danilewskyi var. tinnunculus Wasielewski & Wiilker, 1918; H. crumenius for H. crumenium (Hirst, 1905) Coatney, 1936; H. mathislegeri for H. herodiadis var. mathislegeri Mohammed, 1958; H. nebraskensis for H. noctuae var. nebraskensis Coatney & Roudabush, 1937; H. rileyi for Hoemoproteus rileyi Malkani, 1936; H. sauianae for H. sd-vianae Tendeiro, 1947; H. asturisdussumieri for H. asturis-dussumieri de Mello, 1935 emend. de Mello, 1937; H. xantholemae for H. xantholaemi Zargar, 1945. Of the 133 named species, 114 occur in birds, 16 in reptiles and 3 in amphibia; 14 orders and 47 families of birds are represented. The generic names Halteridium LabbC, 1894, Haemocystidium Castellani & Willey, 1904 and Simondia Garnham, 1966 are considered synonyms of Haemoproteus.