

:, : . . • . METHODS ' 



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All morphometric data were taken as straight-line measurements with 

 needle-point dial calipers and recorded to the nearest 0.1 mm, except for lengths 

 exceeding 170 mm, which were made with a strip tape measure to the nearest 1.0 

 mm. Method of measurements generally followed that of Stewart (1986) and 

 Stewart and Pavlik (1985). Standard length (SL) was recorded as the distance from 

 the tip of the upper lip to the posterior midpoint of the hypural plate. The terms 

 "fin origin" and "fin insertion" are used in the sense of CaiUiet et al. (1986), to mean 

 the front and the rear of the fin, respectively, in the case of both paired and 

 unpaired fins. Pre-fin lengths were taken from the tip of the snout to the fin origin. 

 Predorsal length is the distance from the tip of the snout to the base of the first 

 dorsal spinelet. Distances between fins were measured from fin origins in all cases 

 except that from adipose origin to anal insertion. The distance from the tip of the 

 snout to the upper point of the gill cavity was used in morphometric analyses to 

 represent head length (HL). Head depth was taken at a vertical line passing 

 through the midpoint of the orbit. Occipital head depth was taken at the vertical 

 through the supraoccipital-frontal suture. Gape width is the transverse distance 

 between the bony posterior extremities of the premaxillae. Barbel length was 

 measured from the anteriormost point of the maxillary bone to the distal fleshy tip 

 of the barbel, or, in nuptial males, to the posteriormost bony extension of the barbel 

 (frequently corresponding to the base of a recurved odontode). Barbel groove 

 length is the distance from the anteriormost point of the maxillary bone to the fleshy 

 posterior corner of the upper jaw. Fin-base lengths included fleshy membranous 



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17 



