About us


To overview

17/04/2012 - Colourful river crabs: newly discovered and already threatened

Dresden, 21 March 2012. Scientists at the Senckenberg Research Institute in Dresden and De La Salle University in Manila have discovered four new species of the colourful Insulamon freshwater crab as part of their Aqua Palawana research programme. But various mining projects on the island of Palawan pose a huge threat to these creatures. The relevant study was recently published in the scientific journal Raffles Bulletin of Zoology.

The Philippine island of Palawan is something special. Located between the Sundaic and Philippine region it combines two of the world’s most important biodiversity hotspots. Its bio-geographical special status is also reflected in its fauna and flora. Around 50 per cent of the species living on Palawan are defined as endemic, as they are exclusively native to the island.

A particularly colourful new species: Insulamon
palawanense © Senckenberg

“In the Aqua Palawana research programme I am head of, we have been investigating the biodiversity of Palawan’s inland waters for over 10 years”, says Dr Hendrik Freitag from the Senckenberg Natural History Collections in Dresden. “This also included taking a closer look at the Insulamon crabs and we discovered four new species in the process.”

The reddish violet species of the Insulamon crab genus are the only varieties that are endemic to only one or a few islands. The sea means these creatures are unable to spread elsewhere, as they skip the larval stage in seawater and depend on freshwater at all stages of their development. Having been completely separated from their relatives, they have developed their own separate species and genera over tens of thousands of years.

Insulamon magnum – one of the freshwater crabs
recently discovered on Palawan © Senckenberg

“We have proved that the only previously known type of Insulamon is restricted to the Calamian group of islands to the north of Palawan. The four newly discovered species live exclusively on the actual island of Palawan and make it a unique habitat”, says Freitag.


But this unique biodiversity is under threat. Several mining projects are to be conducted despite massive protests by people from all walks of life and against the resistance of indigenous peoples.
“The smaller the remaining natural habitat the greater is the risk to endemic fauna and flora. Even minor environmental changes can lead to extinctions. It is all the more important to do research in this region and show that the biodiversity of these islands is unique and worth protecting”, says Freitag and

The recently discovered Insulamon
johannchristiani species also exists only on
Palawan © Senckenberg

adds, “that’s why our next step is to investigate Palawan’s species-rich freshwater prawns”.

As an associate professor at the Ateneo de Manila University Freitag increasingly gets local students involved in bio-systematic research, in order to create awareness of this unique habitat.

Participants cooperating in the Aqua Palawana research project in addition to Senckenberg and the Phyllodrom Leipzig are the Ateneo de Manila University, Western Philippines University, De La Salle University Manila and the Philippine National Museum, as well as the Vienna Natural History Museum and the National University of Singapore.

Dr Hendrik Freitag
Senckenberg Natural History Collections Dresden
Museum of Zoology
(currently Ateneo de Manila University:
Tel. 0063 939 2605040)

Revision of the genus Insulamon Ng & Takeda, 1992 (Crustacea: Decapoda: Potamidae) with description of four new species. Hendrik Freitag. The Raffles Bulletin of Zoology, 60(1): 1–239. Pp. 37–55

The study of life forms in their diversity and ecosystems, climate research and geology, the search for life in the past and ultimately the understanding of the entire system of life on earth – this is what the Senckenberg Natural History Society works for. Exhibitions and museums are the showcases of natural science, whereby Senckenberg shares the latest scientific findings with people and provides an insight into bygone ages as well as the diversity of nature. More information is available at www.senckenberg.de.


Press contact

Dr. Sören Dürr
Tel.: 069 7542-1580

Judith Jördens
Tel.: 069 7542-1434
Mobil: 0172-5842340

Anna Lena Schnettler
Tel.: 069 7542-1561


Forschungsinstitut und Naturmuseum
Senckenberganlage 25
60325 Frankfurt


14/08/2018 09:58:41

14/08/2018 09:15:06

14/08/2018 07:29:28