Wednesday, May 05 10:04 am
Another cell with outer envelope teased open, soil closure removed, and inner envelope closure also teased open, top view. Credit: J. G. Rozen.
A rare species of solitary bees found in the Middle East, Osmia avoseta, constructs its nests from petals, creating chambers of pink, yellow, blue, and purple for its larvae. The colorful nests moist, secure chambers for the larvae to grow, consume provisions, and build a cocoon to wait out the winter.
“In this species, a female shingles the wall of her brood chambers with large pieces of petals or with whole petals, often of many hues,” says Jerome Rozen, curator in the Division of Invertebrate Zoology at the Museum. “Unfortunately, her larvae never enjoy the brilliant colors of the nest’s walls because they have no eyes—and, anyhow, they would need a flashlight!”
Rozen and colleagues working in Turkey discovered the unusual nests on the same day as a group of colleagues doing field work in Fars Province, Iran. Their research was recently published in American Museum Novitates.
Bees are the most important animal pollinators living today, and many flowering plants depend on bees to reproduce. Nearly 75% of bee species—and there are about 20,000 species described—are solitary. This means that for the majority of bees, a female constructs a nest for herself and provisions each chamber in the nest with food for the larval stage of her brood. Read more »
Thursday, April 15 10:24 am
Stereomicrograph of Tyrannobdella rex jaw showing large teeth on a single jaw. by Phillips, et al. 2010
The new T. rex has ferociously large teeth lining a single jaw — but its length is less than two inches long. Tyrannobdella rex, a new species and genus of leech, was discovered when doctors plucked it from the nose of a girl who’d recently been bathing in an Amazonian river. Described in PLoS ONE, the blood sucker had led to the revision of a group of leeches that has a habit of feeding from body orifices of mammals.
“Because of our analysis of morphology and DNA, we think that Tyrannobdella rex is most closely related to another leech that gets into the mouths of livestock in Mexico,” says Anna Phillips, a graduate student affiliated with the American Museum of Natural History and the first author of the paper. The related species Pintobdella chiapasensis hails from Chiapas and is typically hosted by tapir and cows. Analysis of genetic sequences places these species with others found in the world’s tropics, suggesting that their common ancestor must have lived when the continents were pressed together into a single land mass, or before Pangaea broke up.
“We named it Tyrannobdella rex because of its enormous teeth,” says Mark Siddall, curator in the Division of Invertebrate Zoology. “Besides, the earliest species in this family of these leeches no-doubt shared an environment with dinosaurs about 200 million years ago, when some ancestor of our T. rex may have been up that other T. rex’s nose.”
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For more on Mark Siddall, watch a recent field video of the curator searching for leeches in Rwanda. |
Monday, April 12 11:01 am
Supramap, a powerful new web-based application that tracks pathogens in time and space as they evolve, can help public health officials and national security experts predict and respond to outbreaks of infectious diseases. The program was officially announced in a paper in Cladistics.
“This tool has a lot of predictive power,” says Ward Wheeler, curator in the Division of Invertebrate Zoology at the Museum. “If the movement of a pathogen is related to bird flyways, for example, and those routes are shifting because of something like climate change, we can predict where the disease might logically emerge next.”
Operating on parallel programming on high-performance computing systems at Ohio State University and the Ohio Supercomputer Center, Supramap allows any user to input raw genetic sequences of a pathogen’s strains and build an evolutionary tree based on mutations. The branches are projected onto the globe with pop-up windows to show how strains mutate over space and time and infect new hosts.
Supramap depicting the westward spread of avian influenza (H5N1). Red tree branches indicate a genotype of lysine (K) at amino acid position 627 in the PB2 protein, which confers increase replication in mammals. White tree branches indicate a genotype of glutamic acid (E), the wild type for H5N1. Mutations at each node can be viewed in pop-up windows. From Janies et al. 2010 Cladistics online 04-9-10
In the research paper, Wheeler and colleagues test Supramap’s capability on recent strains of avian influenza (H5N1). The evolutionary tree (see the image), based on 239 sequences of a specific gene, polymerase basic 2, shows that host shifts are highly correlated with a specific gene mutation that allows avian viruses to adapt to mammalian hosts.
“We package the tools in an easy-to-use web-based application so that you don’t need a Ph.D. in evolutionary biology and computer science to understand the trajectory and transmission of a disease,” says Daniel A. Janies, first author of the paper and an associate professor at Ohio State University.
Monday, April 05 3:10 pm
Rare Ethiopian amber deposit offers fresh insights into Cretaceous-period ecosystem. Courtesy PNAS/ Matthias Svojtka
A 95-million-year-old amber deposit uncovered in Ethiopia, the first major discovery of its kind from the African continent, is helping scientists reconstruct an ancient tropical forest and gain new insights into an ecosystem once shared by dinosaurs.
The scientific team—an international group of 20 researchers including Paul Nascimbene of the American Museum of Natural History’s Division of Invertebrate Zoology—describes the findings, which include new fungus, insects, spiders, and even bacteria from the Cretaceous Period, in the current issue of the Proceedings of the National Academy of Sciences. The amber deposit may also provide fresh insights into the rise and diversification of flowering plants during the period.
“Until now, we had discovered virtually no Cretaceous amber sites from the southern hemisphere’s Gondwanan supercontinent,” says Nascimbene. “Significant Cretaceous amber deposits had been found primarily in North America and Eurasia.”
While some of the authors worked on the geological setting and the fossils entombed within the amber, Nascimbene, along with Kenneth Anderson from Southern Illinois University, studied the amber itself. They found that the resin that seeped from these Cretaceous Gondwanan trees is similar chemically to more recent ambers from flowering plants in Miocene deposits found in Mexico and the Dominican Republic. The amber’s chemical designation is Class Ic, and it is the only Ic fossil resin discovered to date from the Cretaceous. All other documented Cretaceous ambers are definitively from non-flowering plants, or gymnosperms.
“The tree that produced the sap is still unknown, but the amber’s chemistry is surprisingly very much like that of a group of more recent New World angiosperms called Hymenaea,” says Nascimbene. “This amber could be from an early angiosperm or a previously-unknown conifer that is quite distinct from the other known Cretaceous amber-producing gymnosperms.”
Other team members discovered 30 arthropods that had been trapped in the amber from thirteen families of insects and spiders. These fossils represent some of the earliest African fossil records for a variety of arthropods, including wasps, moths, beetles, a primitive ant, a rare insect called a zorapteran, and a sheet-web weaving spider. Parasitic fungi that lived on the resin-bearing trees were also found, as well as filaments of bacteria and the remains of flowering plants and ferns.
