Question: What is Pre-caudal length? how do you measure it?

Answer:

Precaudal length (PCL) is also known as normal length and is the length from tip of snout to precaudal pit measured in a straight line.

See Compagno (1984) p.10, PRC = Precaudal length.

Cliff, Dudley & Davis (1990) reported a conversion formula for the PCL/FL pair :

PCL = (FL + 2.053)/1.112 (n = 27, r = 1.0, NSB data, units are cm).

They also give equations between UCL (upper caudal lobe) and PCL and then you could use

TL = PCL + 0.8 UCL (Bass et al. 1997).
 

However, it is better to convert FL to TL using the equation reported by Casey and Kohler (1992):

FL = 0.9286 TL - 1.7101 (n = 199l r2 = 1.0, units are cm).

Henry F. Mollet, Dec 18, 1998