Palaemon serratus
Dorsal teeth  6-7  ventral  4-5

Palaemon elegans
Dorsal teeth  7-9  ventral  3

Palaemon adspersus
Dorsal teeth 5-6  ventral  3 (2-4)

although I am not sure that all the prawns have read the correct books.

With these two species, the colour is definitely not even a guide. About 5% of P. serratus will have distinct blue bands instead of the usual orange bands. This appears to be environmental asif one prawn is this colour, lots of the others are also likely to be bluish.

A fully grown P. serratus is much larger, an edible size and if served up in restaurants the comparison with Pandalus may be more appropriate:

Pandalus
Always over 12 dorsal teeth, so it is easy to tell. Rarely caught locally in the south-west of Britain, although Pandalus montagui is found in deeper water. There are crustacean experts that known their prawns much better than me.

P. serratus has usually got more elegant patterns than P. elegans.

The photographs suggested by Michael Noren <mnore@mbox.su.se > at:
http://www.seamasters.be/bio/geleed/gezaagde.htm
are worth looking at, but I am not sure which species they are. I would be interested in other opinions. Patterns tend towards P. elegans but the dorsal teeth tend towards P. serratus. Both species can be caught in the same net sweep at almost any time of the year, but P. elegans is much more of a shore species, on the northern English Channel coast, off Sussex, Longtitude around GMT, 0 degrees.

It is the smaller prawns that cause the confusion, and other species could conceivably be discovered, but I have not recorded any of the other species, e.g. Palaemon adspersus, Palaemon longirostris, Palaemonentes varians, in fully saline areas and I catch prawns to eat (P. serratus & Crangon crangon) and for fish food (P. elegans).


In Palaemon elegans the dactylus is smaller than in P. serratus: about a third against nearly the half. I agree that the colour pattern looks like P. elegans, but behind the eye socket are only two teeth, also a characteristic of P. serratus. P. adspersus is out of question. Live specimens have a red ventral part of the rostrum.
Gerard Heerebout
Sender: G.R.Heerebout@wxs.nl

-----Original Message-----
From: owner-crust-l@VIMS.EDU [EMail:owner-crust-l@VIMS.EDU]On Behalf Of
Andy Horton
Sent: vrijdag 2 maart 2001 21:28
To: Crustacean List
Subject: [CRUST-L:819] Palaemon serratus v. P. elegans

Hello Gerard,

Thanks for the reply. I would go for P. serratus from the photograph. The dorsal teeth and probably good enough on their own, and in the photograph the size seem right as well. I need my other glasses (spectacles) to look at the further details.

Computer images really help as before I had to photograph them and compare the images on a large projector screen. Either that, or examining them under the magnifying glass on my plate. I have got new close-up lens for my glasses since last summer.

I have no experience of P. adspersus.

Cheers

Andy Horton.


  o">Andy Horton.