The pink handfish - a.k.a. brachionichthys


[tweetmeme source=”handresearch” only_single=false] A few weeks ago (may 2010) Australian researchers Daniel Gledhill & Peter Last from the CSIRO Wealth reported to have discovered 9 new species of the ‘handfish’, in a research that highlights an urgent need to better understand and protect the diversity of life in Australia’s oceans. But the major unanswered question is: ‘two of the handfish fins look like hands, but are they?’

Mr Gledhill described the Handfish as follows:

“Handfishes are small, often strikingly patterned or colourful, sedentary fish that tend to ‘walk’ on the seabed on hand-like fins, rather than swim. Fifty million-years ago, they ‘walked’ the world’s oceans, but now they exist only off eastern and southern Australia“.

One of the newly named species, the Pink Handfish, is known from only four specimens and was last recorded off the Tasman Peninsula in 1999.

Interestingly, if we take a look at some features of red handfish one can notice that it actually isn’t walking with the hands… but with the feet! (See the photos below)

The red handfish - a.k.a. brachionichthys politus!

And in the perspective of evolution it might actually make sense that the hands of the handfish appear to have 4 digits, and the feet have more digits – though 6 digits is really rather remarkable.

Why are 6 digits remarkable?

First of all, the 4-digit hand combined with a 6-digit foot reminds us to a typical characteristics of… amphibians, they are usually featured with 4 digits on the front limbs and 5 digits on the hind limbs!

However, while an amphibian usually spends his live some time on land and some time in the water – there is another rather funny ‘creature’ that has likewise hand- (4 digits) and foot characteristics (5 digits), named: the axolotl – a tiger salamander complex that is living in the waters of Mexico. The difference with the salamander is that the axolotl only lives in the water, just like the handfish!

The axolotl - belonging to the tiger salamander complex!

Most vertebrates have 5 digit limbs!

One should also be aware that most vertibrates (including: mammals, birds, reptiles, amphibians, and various fishes) have 5 digits on each limb. So, from the perspective of evolution it is not a coincidence that us human have 5 finger and 5 toes!

However, in this perspective it is rather remarkable that the handfish appears to have a 6 digit fin!

Would you like to shake hands with a handfish?

Evolution animation: from fish to human!

The mystery of the five fingers!
Five things that your 5 fingers can tell you!
The difference between the human hand & the hands of primates!

Evolution: from fish to human!