Evolutionary relationships between morphology, performance and habitat openness in the lizard genus Niveoscincus (Scincidae: Lygosominae)

Correlations between an animal's morphology and ecological parameters such as habitat characteristics emphasize the intimate link between phenotype and the environment, but are often difficult to interpret because the functional consequences of morphological variation are frequently unknown. We provide one of the few studies relating limb morphology, functional capabilities, and habitat in reptiles. We tested the hypothesis that species occupying open microhabitats would possess relatively longer limbs and faster sprint speeds than those occurring in more closed microhabitats. A number of morphological characteristics relevant to locomotion were quantified, including the length of the bones of the fore- and hindlimbs and body size. A phylogenetic analysis was then used to examine the evolutionary relationships between morphology, locomotor performance and microhabitat openness in seven species of Niveoscincus and one species of the closely related genus Pseudemoia. A significant evolutionary relationship was established between sprinting ability, morphology, and the openness of the microhabitat occupied by a species. The phylogenetic analysis demonstrated an evolutionary trend in Niveoscincus of species occupying open microhabitats (e.g. N. greeni, N ocellatus) being large with long limbs and high sprinting ability, while those occupying closed microhabitats (e.g. N coventryi, P. entrecasteauxii) art smaller with short limbs and much slower maximum sprint speeds.     

Biodiversity of palm fungi in the tropics: are global fungal diversity estimates realistic?

Two questions are addressed: 'How many species of fungi can occur on a single host palm?' and 'What are the implications of this for global estimates of fungal diversity?' Fungal diversity estimates found in the literature are reviewed. Data on the numbers of fungi occurring on the above-ground tissues of six individual palms in the genus Licuala in Australia and Brunei Darussalam (Borneo) are provided. A total of 189 species of fungi were isolated and/or collected from the six palms. In addition, 53 'morphospecies' of mycelia sterilia were isolated, giving a total of 242 taxa from the 2672 isolates/collections made. The three palms in Australia (sampled once) yielded 100 species (each palm supporting an average of 54.7 taxa), while the three palms in Brunei Darussalam (sampled three times) yielded 172 species in total (approximately 111.3 taxa each). The magnitude of global fungal diversity, estimated at 1.5 million species, is discussed. Our results indicate that 33 to 1 would be a more accurate estimate (than 5.7 to 1) of the ratio of host specific fungal to palm species in the tropics. We therefore propose that global estimates of fungal diversity, based on temperate studies, require revision upwards.     

A molecular study of phylogenetic relationships and evolution of antipredator strategies in Australian Diplodactylus geckos, subgenus Strophurus

We present phylogenetic analyses of the lizard genus Diplodactylus subgenus Strophurus using 1646 aligned positions of mitochondrial DNA sequences containing 893 parsimony-informative characters for samples of 12 species of Strophurus and 19 additional Australian gecko species. Sequences from three protein-coding genes (ND1, ND2 and COI) and eight intervening transfer RNA genes were examined using parsimony, maximum-likelihood and Bayesian analyses. Species of Strophurus appeared to form a monophyletic group with the possible exception of S. taenicauda . Strophurus has evolved two distinct defence/display characteristics: caudal glands, which expel an unpalatable substance, and striking mouth colours. Caudal glands appeared to have arisen once in a common ancestor of Strophurus , with dermal augmentation of caudal glands characterizing a subclade within the subgenus. Evolution of yellow and dark-blue mouth colours in Strophurus occurred in the context of diurnal activity and may be interpreted as an augmentation of defensive behavioural displays. Molecular divergence suggests that arboreality evolved in a common ancestor of Oedura and Strophurus approximately 29 Mya and that the caudal glands of Strophurus arose approximately 25 Mya.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 82 , 123–138.     

A LABORATORY TEST FOR EVALUATING CHEMICAL STERILIZERS FOR DAIRY FARMS

SUMMARY: A technique for testing chemical sterilizers for dairy farms, using moulded rubber teat cup liners, is described. Results are based on colony counts of rinses taken after disinfection. The test can be used for comparing a new disinfectant with a standard sodium hypochlorite.     

Polymorphic microsatellite markers in the painted dragon lizard,Ctenophorus pictus

We isolated eight polymorphic microsatellite markers from the painted dragon, Ctenophorus pictus, from a genomic library simultaneously enriched for a suite of di‐, tri‐ and tetranucleotide repeat units. Genetic variation was assessed in 40 individuals from populations in Victoria and South Australia. The number of alleles per locus ranged from four to 45 with observed heterozygosity ranging from 0.23 to 0.95. These markers will be useful for studies of natural and sexual selection and the effects of habitat fragmentation in semiarid Australia.     

Embryoid Formation in Pollen Grains of Nicotiana tabacum

Anthers of Nicotiana tabacum (n = 24) were cultured on nutrientagar and examined at intervals for pollen embryoids. Embryoidswere formed in anthers of varying developmental stage, the youngestof which coincided with the liberation of free microspores fromtetrads, and the oldest with the formation of bicellular grains.This period in the development of the anther occupied 4–5days. Older anthers within this range were more successful thanyounger anthers. The first mitosis of the pollen was typicallyasymmetric and resulted in the formation of unequal generativeand vegetative cells. Some of the grains then went into a lagphase for at least 5–6 days, after which the mitotic conditionwas restored. Embryoids were formed by repeated division ofthe vegetative cell. If the generative cell divided, it didso only once or twice. Occasionally the first mitosis was symmetricand gave rise to equal cells, and in these instances both cellsprobably participated in embryoid formation. The youngest anthersexamined were probably less successful because fewer grainssurvived to enter mitosis. The number of embryoids produced varied considerably from oneanther to another both within the same bud and between differentbuds: values ranging from less than 400 to 10 000 per antherwere encountered. Most of these degenerated after the firstfew divisions, partly because they burst prematurely from thepollen grain wall. Embryoids which continued to develop formedplantlets and/or callus. The largest number of plantlets obtainedfrom one anther was 32. Haploid plantlets were also regeneratedfrom callus by transferring it to a low-sugar medium withoutauxin. The behaviour of grains not forming embryoids was also noted.