22 October 2005

Papers read this week

Joyce, W. G. & Gauthier, J. A. 2004. Palaeoecology of Triassic stem turtles sheds new light on turtle origins. Proc. R. Soc. London B 271:1-5.
I started reading this paper with some hesitations, because I don't know much about either turtles or skeletons in general. But the paper turned out to be easy to follow and understand.

The authors first demonstrated that the forelimbs of extant turtles reflect their habitat preferences, with short-handed turtles being terrestrial and long-handed turtles being aquatic. Then, they applied this analysis to fossils of two species of ancestral turtles from the Triassic. Based on the results of this analysis, they conclude that although the last common ancestor of all living turtles lived in fresh water, the original turtles that came before (the turtle stem lineage) lived on land.

Several years ago while looking for snails, I chanced upon an almost complete turtle skeleton that I meticulously collected. One of these days, I am going to use those bones to teach myself about the turtle skeleton and write a post about it.

Strathdee, A. T. & Bale, J. S. 1998. life on the edge:Insect Ecology in Arctic Environments. Annual Review of Entomology 43:85-106.
The Arctic invertebrate fauna is low in species diversity as well as population densities. This paper discusses the adaptations in morphology, behavior, life cycles and physiology of the Arctic insects that enable them to survive the harsh Arctic environment.

I read this paper not because I am studying the Arctic fauna, but because I have a specific interest in the land snail fauna of high mountains. I believe that there may be parallels between the evolutionary paths taken by the Arctic and montane invertebrates, including snails.

And a series of short, old papers from the Nautilus that I photographed two weeks ago at the Mollusk library at the Smithsonian's Museum of Natural History. They are always fun to read in the train on the way home from work.

Archer, A. F. 1942. Pine woods as adequate habitat types for land mollusca. Nautilus 55:94-97.
The author collected several species of snails in various types of pine woods in Alabama.

Marsh, P. L. 1942. Zoögenetes [sic] harpa (Say) in the Rocky Mountains. Nautilus 55:97-98.
I have written about the intriguing distribution range of Zoogenetes harpa. The author gave records of this species from two locations on the Rocky Mountains. According to his experience, Z. harpa was rare and never present in large numbers.

Ingram, W. M. 1942. Food habits of Haplotrema minimum Ancey and habits of associated mollusks on the Mills College campus. Nautilus 55:98-102.
Haplotrema minimum, a carnivorous land snail, was observed to feed on various species of snails, including juvenile Helix aspersa, a species introduced to California from Europe.

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