18 
Clayton E. Ray, Elaine Anderson, S. David Webb 
However, the separation in size is not absolute. For example, the holo- 
type of T. macrodon falls within the observed range for T. cookii in width 
of P 3 , but widths of anterior premolars have slight diagnostic value. 
Development of lower premolars is highly variable in modern galictines. 
We have noted variations in Eira barbara, for example, ranging from 
several specimens with Pj absent or tiny and spicular, some with spaces 
between the premolars, to others with extremely large, broad, overlap- 
ping premolars. 
Relationships. — The closest relative of Trigonictis macrodon is its 
only congener, T. cookii, distinguished by slightly smaller size. Having 
two carnivores so similar in morphology and size apparently coexisting 
(in the Hagerman, Broadwater, Sand Draw, and Grand View local fau- 
nas) has vexed everyone who has studied these animals. Gazin (1934) 
considered and rejected the possibility of a single species with extraordi- 
narily high sexual and/or individual variation, as did Zakrzewski (1967), 
and Bjork (1970). 
We applied Zakrzewski’s (1967:205-206) method of assessing sexual 
dimorphism to a series of Eira barbara from Panama in the USNM and a 
sample of Grisonella cuja from Argentina and Brazil in the BMNH, as 
the tayra and the little grison show dimorphism in size and should offer a 
more relevant guide to Trigonictis than would the more distantly related 
mustelines used by Zakrzewski. His “sex size ratio” for a given variate is 
obtained by dividing the mean value for males by that for females. Our 
results are as follows: 
Eira barbara 
N 
X 
OR 
Toothrow length 
male 
10 
31.54 
29.6-34.0 
female 
12 
28.77 
26.6-30.2 
sex size ratio 
1.10 
Length of Mj 
male 
14 
10.33 
9.2-11.0 
female 
12 
9.74 
9.1-10.3 
sex size ratio 
1.06 
