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Science News

2 Posts tagged with the brazil tag
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Ralf Britz and his Smithsonian colleague David Johnson have published a paper in the Journal of Morphology on the development of the sucking disc of remoras. Remoras are a group of marine fish that usually attach themselves to sharks or other large fish such as manta rays with their sucking disc.  This lifestyle appears not to harm the shark, nor does it bring any benefit: depending on the species of remora, they eat fragments of the larger fish's food that fall from its mouth;  faeces; or the larger fish's parasites.

 

Echeneis NaturalHistoryMuseum_PictureLibrary_009079_Comp.jpgEcheneis naucrates - watercolour painting by Sydney Parkinson made during Captain Cook's first voyage 1768-1771

 

Ralf's work on the sucker involved examination and comparison of fins of different species of fish to identify the homology of its components - homology is the term used to describe organs in two species that have the same evolutionary origin, despite sometimes different appearance and function (so the human arm and a bat's wing are homologous).  The remora's sucker is not found in other fish - is it a totally new organ, or is it a highly modified version of an organ found in other fish?

 

By studying the development of larval remoras ranging from 9.3 to 26.7 mm in length, they demonstrated that the skeleton of the sucking disc forms by enormous expansion of the dorsal fin supports and the bases of the associated fin spines. The evolution of a sucking disc from a regular spinous dorsal fin seems like a major step in evolution but is actually a gradual process involving small incremental changes of structures during development.


Britz, R. & G. D. Johnson. 2012. Ontogeny and homology of the skeletal elements that form the sucking disc of remoras (Teleostei, Echeneoidei, Echeneidae). Journal of Morphology, 273 (12) 1353-1366 , DOI: 10.1002/jmor.20063


Ralf has also published a paper with a Brazilian colleague, Mônica Toledo-Piza, analysing the egg surface structure of the poorly known and highly venomous freshwater toadfish Thalassophryne amazonica with the NHM's scanning electron microscopes (SEM). Eggs of this fish show a highly unusual and complex system of ridges and intermittent grooves that originate at the equator of the egg and run toward the animal egg pole and end in a spiraling pattern at the micropyle (the only opening for sperm to enter). This striking modification may help to increase the chances of eggs being fertilized.

Britz, R. & M. Toledo-Piza. 2012. Egg surface structure of the freshwater toadfish Thalassophryne amazonica (Teleostei: Batrachoididae) with information on its distribution and natural habitat. Neotropical Ichthyology, 10: 593-599.


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Birds of South and Middle America – recent advances in knowledge

 

Joint British  Ornithologists’ Club/Neotropical BirdClub/Natural History Museum free one-day  symposium

 

29 October  2011, 10.30-17.00, Flett Lecture  Theatre, Natural History Museum, London SW7 5BD

 

Key contact:  Robert Prys-Jones (r.prys-jones@nhm.ac.uk) - if you wish to attend, please email in advance: places are limited.

 

Programme

 

10.30-11.00   Coffee/tea

 

11.00-11.45    Nathalie Seddon (Edward Grey Institute, Oxford University)  Why birds sing at dawn

 

Communal displays of acoustically and visually  signalling  animals include some of the great spectacles of the living world.  Many  of these spectacles involve large communities of different species   signalling in concert, often just before sunrise. Though perhaps best   documented in birds, dawn choruses occur in a wide diversity of other  animals,  from primates and frogs, to lizards and insects. These  signalling events have  long fascinated humans, but despite a century of  speculation, there is little  consensus as to their adaptive  significance. Drawing on a recent study of the  largest dawn chorus of  all, that of the singing birds of Upper   Amazonia, to discuss how  ecology, social interactions and  evolutionary history drive birds to  synchronise their songs at daybreak.

 

11.45-12.30     Huw Lloyd (Manchester Metropolitan   University) Conservation of High Andean forest birds in Peru


The  loss and degradation of high-Andean Polylepis woodlands is of particular international concern because of its highly   fragmented distribution, the inadequacy of its protection within  national  reserves, and the high levels of habitat-restricted endemism  amongst its  threatened bird communities. This talk will discuss some of  the most  recent ornithological findings from southern Peru, that could  lead to the  development of effective and realistic habitat restoration  strategies for  populations of these severely threatened bird species.

 

12.30-13.15    James Lowen (Bradt Travel Guides) Wildlife of the Pantanal, South   America’s Serengeti


The world's largest wetland and the aquatic heart of South  America showcases some of the most breathtaking  gatherings of birds,  mammals and reptiles you could ever hope to see. The  author of a new  book to Pantanal wildlife and travel treats us to a visual  celebration  of the region's wildlife spectacles, with a particular focus on the   region's avian specialities and their conservation.

 

13.15-14.15    Lunch (not provided)

 

14.15-15.00    Cristina Banks-Leite (Imperial College  London) * Understorey bird responses to deforestation in  the Atlantic Forest of Brazil


The  Atlantic Forest has been reduced to only 15 per cent of   its original area, whilst much of the extant forest is degraded and  fragmented.  Such altered conditions pose a great threat to the  persistence of a highly  endemic and diverse avifauna; however, our  ability to build effective  conservation measures is impaired by an  imperfect understanding of how  communities respond to deforestation.  Through the analysis of a dataset consisting  of over 7000 birds from  140 species captured in the Atlantic Forest of Brazil,  the speaker will  show how the understory bird community responds to habitat loss,   fragmentation and degradation at multiple spatial and temporal scales.


15.00-15.45    Robert Prys-Jones (Natural History   Museum) Project BioMap: documenting the global museum  resource of Colombian birds for research and conservation


Project BioMap, a tri-national initiative between  British,  Colombian and United    States institutions, began in late 2001. The   project aim was to digitise and verify all Colombian bird specimens  deposited  in natural history museums around the world. A total of  217,802 Colombian bird  specimens in 88 museums were databased and  georeferenced (whenever possible)  and made available online.  My talk will present a  temporal and spatial breakdown of the  information available, highlighting  strengths and weaknesses, and  discuss its use in research and conservation.

 

15.45-16.15                Coffee/tea

 

16.15-17.00    Thomas Donegan (ProAves) Exploring, studying and protecting  the world's most diverse national avifauna


The publication in 2010 of a new field guide  for Colombia is  a  good point to take stock of recent advances in knowledge in the   world's most diverse country for birds. Explorations and discoveries   facilitated by the improving security situation and the increasing  capacity  of national researchers and institutions have resulted in  significant recent  findings (new species, splits, lumps,  new records, etc.), many of  which will be discussed.  An illustrated  discussion of some of the steps  being taken to conserve Colombia's   birds and their habitats will also be presented.