Beaks

[olgacguven]

In some of the scientific journals about the beak analysis I have found some terms about beak measurements such as Lower rostral length (LRL) and upper rostral length (URL). I will be very grateful if someone can explain me these terms. If its possible with figures. thanks....

 

[Graeme]

Gaagh! Mouthpart Terminology!! erm..... Right, I'm guessing that'd be the upper and lower half of the beak. I'm not toally clued up on Ceph mouthpart morphology, but that would be my best guess! There's so many words describing different parts of mouthparts, which in Arthropods in very easy since all the mouthparts are practically seperate. But when you start getting into animals with "2" mouthparts then it starts to become hazy.

Graeme

 

[OB]

Hi there Olgac!

I trust you'll find http://www.museum.vic.gov.au/sciencereports/docs/6_lufigs1.pdf helpful, to this respect.

Cheers,

Olaf

 

[olgacguven]

thank you very much for your interest....

 

[Jean]

Olac

Are you measuring beaks???? What species??? I've measured a wee few Nototodarus sloanii beaks and the odd Moroteuthis ingens ones........................what fun One wee bit of advice use digital calipers if you can.........so much easier on the eyes!

Cheers

J

 

[olgacguven]

I am planing to measure three difrent species in Antalya Bay TURKEY (S. officinalis, L. vulgaris, E. cirrosa)

 

[Jean]

I am planing to measure three difrent species in Antalya Bay TURKEY (S. officinalis, L. vulgaris, E. cirrosa)

That sounds interesting. Are you doing RL to mantle length regressions? It's nice to hear someone else measuring gazillions of beaks!!!!!


J

 

[olgacguven]

I hope so. For the present I am collecting past journals to determine useful metod.

 

[Steve O'Shea]

You'll have a bit of 'fun' measuring rostral length of the lower beak in an octopod, given the lack of a clearly defined 'jaw angle'. Prepare to pull your hair out; differentiating beaks can be tremendous fun (and equally frustrating). When doing so, especially when comparing closely related taxa, keep in mind that the differences between them might not be obviously mathematical (especially if you limit yourself to a few basic measurements), but in some other less-easy-to-define character state.

Take a good look at those beaks ... throw your ruler away .... and understand how they are put together. Differences are remarkably subtle, but once familiar with beak construction they are as distinct as apples and oranges (or pears as those in the UK might say).

 

[Jean]

yup good ol' rostral gap, hood length, crest length, wing length.............

J