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32 Posts tagged with the zoology tag

The NHM has a strong record in scientific research on parasitic worms, particularly evolution and identification, with wide international collaboration.  Parasitic worms can cause serious health effects in humans and other organisms, so scientific understanding is essential for effective control.


The research groups produce many scientific papers every year, but two produced in 2008 have just been recognised as being especially influential in the subject, having been mentioned ("cited") most frequently as being of importance by other scientists in their publications.


Dr Peter Olson (Zoology) recently received recognition for the “Top Cited Article 2008-2010” from Parasitology International for an invited review paper on Hox genes and parasitic flatworms. (Hox genes control part of the sequence of development of animals from egg to adult) The paper reviews the history of work on Hox genes in the phylum Platyhelminthes, introduces new data from the model tapeworm Hymenolepis, and sets the stage for how the study of developmental genes can inform a series of outstanding questions in the evolution of the parasitic forms.


Olson PD. 2008. Hox genes and the parasitic flatworms: New opportunities, challenges and lessons from the free-living. Parasitology International 57, 8-17.


Dr Rod Bray (Scientific Associate Zoology) is similarly an author on the Top Cited Article 2008-2010, this time in the International Journal for Parasitology. The paper presents the accumulated evidence for a major change in the classifiation of the orders of the Class Cestoda (tapeworms).


The old order Pseudophyllidea, which included tetrapod parasites, such as the common human tapeworm Diphyllobothrium latum, and fish parasites, such as the freshwater pest species Bothriocephalus acheilognathi, is separated into two orders. The fish parasites are included in the order Bothriocephalidae and the tetrapod parasites now make up the order Diphyllobothriidea. These groups have long been thought to be distinct - but closely related - and probably monophyletic (arising from one common evolutionary ancestor). 


However, classifications based on molecular data (DNA) from several sources indicate that these groups are polyphyletic (arising from several different evolutionary origins, and therefore not a natural group in evolutionary terms). The conclusion from the molecular results has been backed up by both new and previously reported morphological and biological information. Latest evidence suggests that the Diphyllobothriidea is closest to the unsegmented ‘primitive’ tapeworms, but the Bothriocephalidea is sister to the ‘higher’ tapeworm orders.

Kuchta, R., Scholz, T., Brabec, J. and Bray, R.A. (2008). Suppression of the tapeworm order Pseudophyllidea (Platyhelminthes: Eucestoda) and the proposal of two new orders, Bothriocephalidea and Diphyllobothriidea. International Journal for Parasitology, 38, 49-55. doi:10.1016/j.ijpara.2007.08.005.




Bryozoans are colonial invertebrates, commonly found attached to hard surfaces from the shallow subtidal zone to the deep sea. Bryozoan colonies increase in size by the budding of the numerous individuals (zooids) that make up the colony.


A collaborative team, including Professor Beth Okamura, Dr Tanya Knowles and Dr Paul Taylor from the NHM, explored how the size of zooids in fossil bryozoans varied as temperature changed.  This enabled them to use bryozoans to deduce the annual ranges of temperature during the Early Pliocene (around 4 million to 5.5 million years ago) in the Weddell Sea off the coast of  Antarctica.


Their results show that during this period the climate was warmer than that of the present day, suggesting an ice-free environment in that part of Antarctica.


The research shows the value of fossil bryozoans from shallow seas as a tool for reconstructing seasonal variation in climate in near-polar latitudes in past periods of the Earth's history.  This helps to understand how climates have changed naturally in the past - knowledge that in turn enables present-day changes in climate to be understood and predicted.


Clark, N., Williams, M., Okamura, B., Smellie, J., Nelson, A., Knowles, T., Taylor, P., Leng, M., Zalasiewicz, J. & Hayward, A. 2010. Early Pliocene Weddell Sea seasonality determined from bryozoans. Stratigraphy 7: 199-206.

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