research

Friday, November 19, 2010

Limbless Lizards

Usually, your close relatives resemble you.  Or at least they have the same number of limbs.

Cameron Siler

Not true, however, for Brachymeles lukbani, a species recently discovered by Cameron Siler, one of the museum's graduate students in herpetology.  This critter (which has lost its limbs through evolution) looks like a snake but is actually a skink — a type of lizard.  The genus Brachymeles has a diverse membership. 

"They have the full suite from limbed to limbless, from working limbs with five fingers to no limbs at all," says Siler. 

But this makes the lizards an excellent group for studying how and why limb loss occurs.  Brachymeles lukbani "swims" through rotten logs and undergrowth, looking for food.  In that situation, possessing limbs might not be very useful, or even counter-productive. 

Siler's research has increased the museum's holdings of skinks, making it a leader in skink research

Tuesday, August 2, 2011

Recent Discovery in China Relates to KU Research

fossil

While a recent discovery may change textbooks and the way that many scientists think about bird and dinosaur evolution, it comes as no surprise us.

This week, Xing Xu, H. You, K. Du and F. Han published in the journal Nature a reanalysis of early bird evolution. The analysis knocks Archaeopteryx off its perch as a grandfather to later birds. 

KU has been the central hub for the discovery of the fossil bird beds in the Early Cretaceous of China with the description of the primitive bird, Confuciusornis, and has continued to be involved with all the new discoveries coming out of this region in part through an alumnus of the KU vertebrate paleontology program.

The alumnus, Zhonghe Zhou, presently leads Chinese studies in that region and was recently elected to the prestigious National Academy of Sciences.  Zhou and one of the paper’s authors, Xing Xu, had already precipitated a revolution in our understanding of bird evolution with the discovery of the four-winged gliding bird/dinosaur, Microraptor. With Microraptor, they showed that bird flight began with gliding. 

Zhou has a long-term collaboration with KU vertebrate paleontology researchers at the Biodiversity Institute. Preparator David Burnham, collection manager Desui Miao and I regularly visit China to work on early birds. Our research also has suggested that Archaeopteryx along with other archaic birds represents a side branch that split off much earlier than the new bird, Xiaotingia, and its sister Anchiornis, another four-winged gliding animal. 

While the recent paper in Nature calls these animals “feathered dinosaurs,” we think that they and their common ancestor with modern birds can be best considered true birds. Rather than removing Archaeopteryx from Aves because its avian features were shared with birdlike dinosaurs, we place a stronger emphasis on these features thereby pulling the dinosaur-like birds into Aves. This limits these flying, feathered animals to the Class Aves and pushes the origin of birds into the Early Jurassic or Late Triassic at about the same time as the dinosaurs themselves.

Wednesday, November 25, 2009

Success on first collection trip!

I arrived in Moorea on a Saturday morning and quickly settled into the lab and accommodations. On my first afternoon I went out collecting with Dr. Arthur Anker and Ms. Sarah McPherson (both of the Florida Museum of Natural History) to search for sea anemones at Papetoai. At low tide, we waded in water about 0.5 m deep on a sandy/muddy substrate, flipping over dead coral boulders and rocks looking for sea anemones hidden from plain view.

Specimen of sea anemone specimens Triactis producta attached to a dead coral boulder

Sure enough, hidden under boulders we found specimens of the sea anemone species Triactis producta. This is one of the species I am researching for my Ph.D. and I have already collected specimens from the Red Sea, Zanzibar, Maldives, and Australia! The photo below shows one of the specimens attached to a rock – if you look closely, you can see transparent tentacles at the top of the animal, and a skirt of dark brown tissue about mid-way down the column. This extra tissue of the anemone is full of zooxanthellae. Zooxanthellae are intracellular symbionts (organisms in a symbiotic relationship) that photosynthesize and produce sugars the anemone can use. The specimen in the photo was about 7 mm tall, so you can imagine that it takes a well-trained eye to spot them in the field!

After I collected these specimens, I took them back to laboratory at the Gump Research Station to look at them under the microscope and make more detailed observations. Once I am finished photographing and observing them, some specimens are preserved in 95% ethanol and the rest in 10% formalin. The ethanol specimens will be used for molecular studies while the formalin specimens will be used to study the morphology of the anemones. I can’t wait to get back into the field to collect more sea anemones!

—Andrea Crowther