Extinction threat to turtles

02 May 2012
338 times
Josep Marmi in his office.

Josep Marmi, in his office at the ICP, with a copy of the book.

ICP researchers have participated in the book Turtles: Anatomy, Ecology and Conservation, published by Nova Science Publishers, with a chapter on the evolution and current status of turtles. From the fossil record and contrasting with data from extant species, the authors review the relationship of turtles with their closest relatives, the evolution of its unique body pattern, their diversification and they also analyze the risk of extinction of the living lineages. The conclusions are that much of the current diversity of turtles is in danger.

 

In the book Turtles: Anatomy, Ecology and Conservation, ICP researchers Josep Marmi  and Angel H. Lujan make a review of the current knowledge about the evolutionary history of turtles: from its origins, about 225 million years, until today. The chapter signed by these researchers, "An overview of the diversity of living Threatened Phylogenetic Testudines based on a review of the complex evolutionary history of turtles", contains an updated review of the fossil record- based knowledge and of the phylogeny of turtles, together with data from the International Union for the Conservation of Nature (IUCN) on the conservation status of current species. The results are worrisome, as only three of the current lineages have a relatively low risk of extinction. The rest, up to 11 lineages, have a moderate or high risk of extinction. In fact, in three cases, the lineages have only one endangered or critically endangered species. The conclusions are thus very clear: most of the branches of the evolutionary tree of the extant turtles are threatened with extinction.

The chapter explores the phylogenetic relationships of turtles to other amniotes, the group of vertebrates including reptiles, birds and mammals. Turtles are a rara avis in this group, since they present peculiar characteristics such as the presence of the shell. From the published paleontological studies, the evolution of this structure is explained and the various ecological patterns are described. As Josep Marmi explains, along their evolutionary history, turtles have adapted to different environments, from fully terrestrial to the completely marine. This is reflected in the form of their extremities and in the shell. The chapter goes on to explain how the different turtle lineages diversified over 225 million years.

Cover of the book.

Cover of the book published by Nova Science Publishers.

The second half of the chapter focuses on the current status of turtles. On the one hand, it explains when existing groups originated, and on the other hand, information gathered by IUCN regarding the conservation status of these animals is incorporated. The joint analysis of data from extant and extinct species, allows Josep Marmi and Angel H. Lujan discuss the number of lineages that could disappear if the threatened species that they contain get extinct. And the ICP researchers conclude that most of the turtles’ surviving evolutionary tree is seriously threatened with extinction. The extinction of the turtles would represent, therefore, the disappearance of a unique body pattern in vertebrates.

In the same book, published by Nova Science Publishers, other articles are collected on the anatomy, ecology and conservation of turtles. The remaining chapters present data and studies on the accumulation and distribution of metals in turtles tissues as bioindicators of marine pollution;  mortality of sea turtles from the Canary Islands; the painted turtle as a model of tolerance to anoxia, the lack of breathable oxygen in the cells or tissues of an organism; or how freshwater turtles respond to drought.

+ info Marmi J, Luján AH (2012) An overview of the threatened phylogenetic diversity of living testudines based o a review of the complex evolutionary history of turtles. In: Cosgrove MJ, Roe SA (Eds) Turtles: Anatomy, Ecology and Conservation. Pp. 117-150. Nova Science Publishers, New York. (amazon, ebook)

 

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