Sleepy lizards Tiliqua rugosa are large, long-lived, Australian skinks that live in stable home ranges. Previous studies showed that the lizards have a good sense of orientation and navigation towards home. However, since they are active only 4 months in every year, there is a question about which environmental cues enable them to locate their home boundaries. In the present study we determined whether surrounding olfactory and chemical cues are important for the sleepy lizards for home-range maintenance. In the first part of the study we showed in the laboratory that zinc sulphate (ZnSO4) is a chemical that induces anosmia and prevents detection of chemical cues in sleepy lizards for up to 30 days, with no evident long-term harm to the animals. We then monitored the location of 50 radio-tagged sleepy lizards. After determining their home ranges they were divided into three groups: an untreated control, a saline-treated (sham-operated) group and a ZnSO4-treated group. Starting 2 days after the treatment, the home ranges of all lizards were re-determined within the period that ZnSO4 blocked olfaction. Three variables were calculated comparing home ranges before and after treatments: the change in home-range size, the distance between the centre of activities of the lizards, and the overlap between the individual home ranges before and after treatments. Lizard home ranges varied from 1.9 ± 0.6 ha to 4.6 ± 1.4 ha before treatment, and 1.3 ± 0.3 ha to 3.1 ± 0.7 ha after treatment. There was no significant effect of treatments or of sex on the home-range size or on the distances between the centre of activities, or on the overlap between the individual home ranges. Our data indicate that olfaction and vomerolfaction are not a major cue for home-range maintenance in the sleepy lizards.

Although there has been extensive research on bottlenose dolphins (genus Tursiops), much controversy over the classification within this genus still exists. Even though many morphological variants occur, the prevailing view is for a single species, Tursiops truncatus (Montagu, 1821). To evaluate this view, two sympatric forms of bottlenose dolphins inhabiting Chinese waters were examined using multivariate statistical analyses of osteological data for two meristic and 18 cranial morphometric characters from 71 specimens. Cluster and principal components analyses revealed clear osteological separation of the two forms. Furthermore, the distributions of the total number of vertebrae and several proportions of cranial characters were non-overlapping between the two forms. These results provided strong evidence that the two sympatric forms of Tursiops in Chinese waters are isolated reproductively and do not support the current view of a monotypic genus. Classification functions of a discriminant analysis and a key of several characters were developed to help researchers identify unassigned specimens. Provisional names (T. truncatus and T. aduncus) were suggested, but a formal taxonomic revision of this genus is still required. However, regardless of the nomenclature, immediate amendments to all present wildlife conservation legislation are strongly urged.

A type of apparent photoreceptor, the nuchal organ, is described in the sepiolid squid Euprymna scolopes. These vesicles are identified in a variety of other cephalopod species. The nuchal organs have specific structural similarities to the already well-described photosensitive vesicles. Both organs have a distinct vesiculate structure and possess a rind consisting of several types of cells. Certain rind cells from both organs send processes with microvilli into the lumen of the vesicle forming a core area. Within the cores of both organs numerous microvilli occupy much of the core volume. These histological similarities provide strong evidence that the nuchal organs, like the photosensitive vesicles, are photoreceptors. Three distinct differences also exist between the nuchal organs and photosensitive vesicles: (1) the location of the nuchal organs differs from that of all known photosensitive vesicles in cephalopods; (2) the location of the nuchal organs is highly conservative in decapod cephalopods compared to the varying locations of the photosensitive vesicles; (3) the degree of structural order generally found within photosensitive vesicles is not apparent in the nuchal organs. The function of the nuchal organ is probably different from previously described photoreceptors in cephalopods.

The energetics and burrowing behaviour of the semifossorial Octodon degus (Rodentia: Octodontidae) were investigated and compared with that of more specialized fossorial rodents. An open-flow respirometry system was used to record energy expenditure of single degus inside respirometers partially filled with soft (moist) or hard (dry) soil. In addition, digging behaviour was recorded in groups of three animals inside a large terrarium under controlled conditions of food, photoperiod and temperature. In the field, the digging activity of degus was monitored, along with seasonal variations in rainfall, content of soil moisture and soil hardness. Mass-specific metabolic rate during digging was found to be higher in animals burrowing in soft soils compared to hard soil. However, animals burrowing in soft soil removed more soil per min than animals in hard soil. Thus, gram per gram, excavating in hard soil was energetically more expensive. The digging cost of semifossorial degus tends to be either similar to or above those of similarly sized, but more fossorial, rodents. In the field, heightened digging activity coincided with the occurrence of rainfall, greater content of soil moisture and relatively soft soil conditions. Degus generally use their front feet and teeth to shear the soil; disposal of accumulated debris being carried out by moving their front and hind feet backwards. We also observed the establishment of digging chains when two or three individuals burrowed at the same site. As far as digging is concerned, the behaviour of degus is similar to that of other fossorial rodents, such as African bathyergids and the more closely related South American ctenomyids.

Differences in behaviour, such as the mate-locating tactic, may favour the evolution of interspecific and intersexual differences in the structure of the visual system. This notion was tested by examining the relationships between eye size, body size, sex and mate-locating tactic in 16 species of butterflies. The 16 species were grouped in eight phylogenetically close pairs that differed in the mate-locating tactic displayed by the males. Eye size was characterized by eye surface area, which was estimated from a set of linear eye measurements made on 10 individuals of each sex in each species. The major findings were that eye surface area was positively correlated with body size both among and within species, males have larger eyes relative to their body size than females, and after controlling for body size and phylogeny, interspecific differences in the mate-locating tactic of males does not explain interspecific variation in the size of male eyes or in the magnitude of sexual difference in eye size. The optical and behavioural consequences of variation in eye size with body size and sex will await a better understanding of how eye structure varies with size within and between species.

A new species of Eudendrium from the Chafarinas Islands (south-western Mediterranean) is described. The distinctive character of this species is its association with symbiotic zooxanthellae, a feature in common with Myrionema, the only other genus of the family Eudendriidae. The evolutionary implications of this similarity are discussed. A review of the Mediterranean species of Eudendriidae is presented, including data on the cnidome when available, biological data from the material studied, and a key to identify the Mediterranean species.

Numerous field studies have attempted to assess competition between ungulates through the analysis of resource overlap. However, interpreting the results of these studies has been problematic because low overlap may be the outcome of historical competition and high overlap will result in competition only when that resource becomes limiting. In New Zealand, increasing densities of introduced Himalayan tahr Hemitragus jemlahicus have competitively excluded introduced Alpine chamois Rupicapra rupicapra, but where densities of tahr have been reduced the two species can coexist. This study evaluated the role of habitat selection in the coexistence of these two recently sympatric ungulates in Carneys Creek, eastern Southern Alps, New Zealand. Seasonal habitat selection was estimated by observing unmarked male tahr, female tahr and chamois monthly for 25 months. The proportional availability of six habitats (grassland, grass bluff, rock bluff, shrubland, scree and snow) was measured from aerial photographs taken in each of the four seasons. Although the null hypothesis that tahr and chamois select habitats similarly was rejected in three of four seasons, there was high overlap in preference for grassland and shrubland, and avoidance of scree and snow. Tahr were more often observed in grass bluff and rock bluff than were chamois. Overlap in habitat selection was greatest during winter when snow dominated the landscape, reducing the availability of vegetated habitats. Using Hurlbert's statistic, the niche breadth of chamois was significantly smaller than that of tahr in all seasons except autumn, in which they were similar. These results, together with anecdotal evidence from Carneys Creek, suggest that chamois increase their habitat specialization in the presence of tahr. Although differences in habitat selection are likely to have contributed to the coexistence of chamois with tahr, even relatively small increases in tahr density in some seasons could be expected to exclude chamois from some habitats in Carneys Creek.

Data gathered from the Ministry of Agriculture, Fisheries and Food (MAFF) National Rabbit Survey sites in the 1980s showed substantial site-to-site and year-to-year variation in rabbit Oryctolagus cuniculus abundance. Data on physical and biological factors from 450 sites were collected to seek explanations for this variation. The rabbit abundance index on the 2.25 km transects (walked along the edge of fields, woods, hedges, etc.) was used as the dependent variable for multiple regression and principal components analyses. Additionally, a preliminary attempt at mapping rabbit abundance and distribution in England and Wales using a GIS system was made. Each of the analyses produced a list of the important variables enhancing or reducing rabbit indices. Common to each list were aspects of woodland – area, number of pieces and length of edge; the dryness and patchiness of soils on site; rainfall in late winter, or variables associated with wetness of soil (e.g. number of days with rain, altitude). Other important variables included predator removal policy and the site location nationally. The two strongest components, woodland parameters and predator removal policy, are under human influence. The effects of region, county and year were small, but year-to-year variation within sites was larger, suggesting that rabbit populations were reacting markedly to unmeasured variables, e.g. myxomatosis outbreaks. The analysis provides a useful explanation of the factors that affect rabbit populations and a basis for how these factors may be manipulated.

It has been postulated that the variation in an animal's body temperature during different phases of bone deposition can be estimated from the variation in the ratio of two oxygen isotopes in phosphate recovered from its fossil. Using data from a fossil Tyrannosaurus rex skeleton, the previous researchers failed to reject the null hypothesis that the variation found in bones from the body core is significantly less than that found in the extremities; they also failed to reject the null hypothesis that the coldest and hottest parts of the body differed by less than 4 °C. This suggests that either both null hypotheses are true, or that they are false but the statistical tests used were not powerful enough to detect this. Here I use calculation of confidence intervals to differentiate between these two alternatives. In the first case, I find that the data are consistent with the variance in both the core and the extremity being up to 2.5 times that of the other. In the second case, I show that observations are consistent with temperature differences ranging from 2.6 °C to 6.4 °C. Hence, neither case provides any real support for the hypothesis that bone deposition in this specimen occurred under essentially thermostable conditions.

Genetic variation and the allozymic relationships of five families comprising 23 species of hystricognath rodents were examined using electrophoretic data from 19 presumptive gene loci. Direct-count heterozygosity ranged from 0% to 13.6%, and polymorphism varied from 0% to 36.8%. Fixed allele differences were instrumental for the segregation of taxa as summarized by the Distance Wagner procedure and by majority-rule consensus trees. The monophyly of the Octodontidae, and the family rank of the Abrocomidae and Ctenomyidae is supported by the data. Monotypic Myocastor coypus is not resolved as a distinct family but appeared within the Caviidae. Within the Octodontidae, paraphyly was detected in polytypic Octodon, whereas a high bootstrap value supported the node containing the desert specialists O. mimax (2n = 56) and Tympanoctomys barreare (2n = 102). The implications of allozymic data as a robust phylogenetic signal that connected biochemical associations to the prediction of tetraploidy in T. barrerae are discussed.

Four main types of radula are found within the gastropod superfamily Conoidea. Type 1, the Clavidae type has five teeth in each row with comb-like laterals and flat pointed marginals. Type 2, the Turridae type has two or three teeth in a row with the marginals comprised of teeth with the duplex or wishbone form. Type 3, the Pseudomelatomidae/Pervicaciinae type has two or three teeth in a row with the marginals curved and solid. Type 4, the hypodermic type has two hollow, enrolled, marginal teeth in each row with the radular membrane reduced or absent. Study of the maturing teeth along the radular membrane in gastropods with the Type 2 radula shows that the duplex teeth are not formed from two separate elements but develop from a flat plate, by thickening of the tooth edges and elevation of the posterior edge from the membrane. Semi-enrolled and enrolled teeth of Pilsbryspira, Imaclava and Toxiclionella develop in a similar way. In Conidae where a vestigial radular membrane is attached only at the base of the teeth, the teeth are enrolled from first formation in the radular sac. This study demonstrates that duplex and enrolled teeth develop by a similar process, allowing the possibility of deriving hypodermic teeth from duplex clades as has been suggested by previous phylogenetic analysis.

Contrary to large-scale disturbances, animals constantly create small-scale patches of various kinds during the course of their daily life. For example, rooting by wild boars is a recurrent disturbance regime, which varies in frequency and extent. Rooting by wild boars (Sus scrofa L.) in south-central Sweden was therefore studied by censusing three times per year during 1992–1995 along fixed transects in the Tullgarn Nature Reserve. Significant differences were found in soil surface area being rooted by wild boar between year, season, habitat type and soil category. The amount of surface being rooted varied between 2.4 and 14.2 ha on 226 ha censused. The rooted surface in relation to the ground available was higher in deciduous compared to coniferous forests and grassland. Furthermore, the rooted surface in relation to available ground to root was much higher in damp soil than in dry soil. Mesic soil was used according to availability. Rooted patches showed large variation in size between year, season, habitat type and soil category. Within the three habitat types the largest patches were found in deciduous forests and the smallest in grasslands while in the different soil categories, the largest patches were found in damp soils and the smallest in dry soils. Results are discussed in terms of plant species diversity on a regional scale.