| Clams befouling Tahoe invade Adirondack lake in NY By MARY ESCH 2010-09-03T18:12:35ZBOLTON LANDING, N.Y. (AP) -- A thumbnail-sized clam blamed for clouding the azure bays of Lake Tahoe high in the Sierra Nevada has now turned up in a mountain-ringed Adirondack lake renowned for its limpid, spring-fed waters.... hosted.ap.org |
A Rare Atlantic Hurricane Triple Header Three simultaneous hurricanes rumble in the Atlantic and Caribbean. feeds.nytimes.com |
Mystery Bird: Southern screamer, Chauna torquata | GrrlScientist That crazy South American mystery bird with the pointy daggers on its wings has been demystified!Southern screamer, Chauna torquata, also known as the crested screamer. This individual was photographed in a zoo, but the species is found in tropical and sub-tropical swamps, estuaries and watersides in South America, from Venezuela to northern Argentina. Image: Steven Duncan [larger view].Nikon D200 w/ AFS 70-200m f/2.8 VR lens, hand-held @ 200mm 1/400 sec f4This next photograph might give you a little more information to base your identification on.Southern Screamer, Chauna torquata, also known as the Crested Screamer. This individual is the same as the one in the above photograph. Image: Steven Duncan [larger view].Nikon D200 w/ AFS 70-200m f/2.8 VR lens, hand-held @ 200mm 1/400 sec f4Question: This common species, endemic to South America, is part of a small group of birds that lack a structural feature that is unique to birds and their early ancestors. This same feature is shared with several endangered reptilian species, which are sometimes referred to as "living fossils". Can you tell me what that structure might be? It also has another special structure (pictured above) that has a specific function. What might that function be?Response: The Southern screamer, Chauna torquata, is one of three species in the avian family, Anhimidae. This family is placed into the order Anseriformes – the most familiar of which are ducks and geese. In addition to the fact that the Anhimidae (commonly known as "screamers"), are generally strange birds anyway, but they show that indeed, there is "an exception to every rule". They are unique among living birds because they alone lack the characteristic uncinate processes on their ribs. Uncinate processes are bony extensions found on the back of each rib that overlap the next rib, thereby serving to strengthen the rib cage of birds. Don't believe me? Take a close look at poultry rib bones the next time you eat one. Bird rib bones look like nothing else out there. Mostly. Uncinate processes are mostly confined to birds: The only other living non-avian animal with uncinate processes on its ribs are Tuatara, two species of endangered reptile found exclusively in New Zealand. (It is interesting to note that even though recent morphological and DNA work show they have changed significantly from their fossilised ancestors, Tuatara retain many ancestral characters and thus are sometimes referred to – incorrectly – as "living fossils.") Tuatara are fascinating for many reasons, not the least of which is that they are also "exceptions to the rule". Well, several rules, actually. The other remarkable feature about screamers is the one that appears in the photographs: that large pointed "dagger" or spur on the wrist of the bird's wing. As you probably have guessed, these large spurs are instruments of war, used in fights over mates and territory. If these spurs become embedded in a rival, they can break off, but are then renewed. If you have bird images, video or mp3 files that you'd like to share with a large and appreciate audience, feel free to email them to me for consideration.GrrlScientistguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Video | Becoming a gorilla Ape actor Peter Elliott walks us through gorilla behaviour, vocalisations and gait guardian.co.uk |
Indonesia warns volcano could erupt at any time By SLAMET RIYADI 2010-10-25T14:25:11ZMOUNT MERAPI, Indonesia (AP) -- Indonesia warned Monday that its most volatile volcano could erupt at any time and started evacuating some of the thousands of villagers living on the mountain's slope.... hosted.ap.org |