Chemical effects of diceCT staining protocols on fluid-preserved avian specimens.

Diffusible iodine-based contrast-enhanced computed tomography (diceCT) techniques allow visualization of soft tissues of fluid-preserved specimens in three dimensions without dissection or histology. Two popular diceCT stains, iodine-potassium iodide (I2KI) dissolved in water and elemental iodine (I2) dissolved in 100% ethanol (EtOH), yield striking results. Despite the widespread use of these stains in clinical and biological fields, the molecular mechanisms that result in color change and radiopacity attributed to iodine staining are poorly understood. Requests to apply these stains to anatomical specimens preserved in natural history museums are increasing, yet curators have little information about the potential for degradation of treated specimens. To assess the molecular effects of iodine staining on typical museum specimens, we compared the two popular stains and two relatively unexplored stains (I2KI in 70% EtOH, I2 in 70% EtOH). House sparrows (Passer domesticus) were collected and preserved under uniform conditions following standard museum protocols, and each was then subjected to one of the stains. Results show that the three ethanol-based stains worked equally well (producing fully stained, life-like, publication quality scans) but in different timeframes (five, six, or eight weeks). The specimen in I2KI in water became degraded in physical condition, including developing flexible, demineralized bones. The ethanol-based methods also resulted in some demineralization but less than the water-based stain. The pH of the water-based stain was notably acidic compared to the water used as solvent in the stain. Our molecular analyses indicate that whereas none of the stains resulted in unacceptable levels of protein degradation, the bones of a specimen stained with I2KI in water demineralized throughout the staining process. We conclude that staining with I2KI or elemental I2 in 70% EtOH can yield high-quality soft-tissue visualization in a timeframe that is similar to that of better-known iodine-based stains, with lower risk of negative impacts on specimen condition.

Does solar irradiation drive community assembly of vulture plumage microbiotas?

BACKGROUND: Stereotyped sunning behaviour in birds has been hypothesized to inhibit keratin-degrading bacteria but there is little evidence that solar irradiation affects community assembly and abundance of plumage microbiota. The monophyletic New World vultures (Cathartiformes) are renowned for scavenging vertebrate carrion, spread-wing sunning at roosts, and thermal soaring. Few avian species experience greater exposure to solar irradiation. We used 16S rRNA sequencing to investigate the plumage microbiota of wild individuals of five sympatric species of vultures in Guyana. RESULTS: The exceptionally diverse plumage microbiotas (631 genera of Bacteria and Archaea) were numerically dominated by bacterial genera resistant to ultraviolet (UV) light, desiccation, and high ambient temperatures, and genera known for forming desiccation-resistant endospores (phylum Firmicutes, order Clostridiales). The extremophile genera Deinococcus (phylum Deinococcus-Thermus) and Hymenobacter (phylum, Bacteroidetes), rare in vertebrate gut microbiotas, accounted for 9.1% of 2.7 million sequences (CSS normalized and log2 transformed). Five bacterial genera known to exhibit strong keratinolytic capacities in vitro (Bacillus, Enterococcus, Pseudomonas, Staphylococcus, and Streptomyces) were less abundant (totaling 4%) in vulture plumage. CONCLUSIONS: Bacterial rank-abundance profiles from melanized vulture plumage have no known analog in the integumentary systems of terrestrial vertebrates. The prominence of UV-resistant extremophiles suggests that solar irradiation may play a significant role in the assembly of vulture plumage microbiotas. Our results highlight the need for controlled in vivo experiments to test the effects of UV on microbial communities of avian plumage.

A distinctive new species of flowerpecker (Passeriformes: Dicaeidae) from Borneo.

The enigmatic 'Spectacled Flowerpecker'-a probable new bird species from the island of Borneo-was first sighted in the Danum Valley of Sabah, Malaysia in 2009. However, the absence of a holotype specimen has prevented its formal scientific description. Since then only a handful of reports from widely disparate localities across the island have emerged, all from lowland sites and often in close association with fruiting mistletoe. Here, we report the long-awaited capture of a specimen of this putative new species and confirm its morphological and molecular distinctiveness as a novel species in the genus Dicaeum.

Two new picobiin mite species (Acari: Cheyletoidea: Syringophilidae) parasitizing passerine birds in Guyana.

Two new picobiin mite species (Cheyletoidea: Syringophilidae) are described from passeriform birds in Guyana, Rafapicobia automoli sp. nov. parasitizing two furnariid species Automolus ochrolaemus (Tschudi) (type host) and Automolus rufipileatus (Pelzeln) (Passeriformes: Furnariidae) and Neopicobia herbicolae sp. nov. from Emberizoides herbicola (Vieillot) (Thraupidae). Additionally, Picumnus exilis (Lichtenstein) (Piciformes: Picidae) is recorded as a new host species for Neopicobia hepburni Glowska et Laniecka, 2014.

New species of the genus Picobia (Cheyletoidea: Syringophilidae) parasitizing tyrannid birds (Passeriformes: Tyrannidae).

Three new quill mite species of the genus Picobia Haller (Cheyletoidea: Syringophilidae) are described from 6 host species of the family Tyrannidae (Passeriformes), P. ochoi sp. nov. from Tolmomyias sulphurescens (Spix) (Guyana), P. schmidti sp. nov. from Lophotriccus pileatus (Tschudi) (type host) (Peru) and Hemitriccus margaritaceiventer (Orbigny & Lafresnaye) (Guyana), and P. myiopagi sp. nov. from Myiopagis gaimardii (Orbigny) (type host) (Guyana), M. subplacens (Sclater) (Peru) and Elaenia ruficeps Pelzeln (Guyana).