Blancan Carnivore Trigonictis 19 
Grisonella cuja 
N 
X 
OR 
Toothrow length 
male 
14 
26.19 
22.0-28.4 
female 
11 
23.99 
22.0-25.4 
sex size ratio 
1.09 
Length of Mj- 
male 
14 
7.75 
6.4-8.6 
female 
11 
6.89 
6.3-7.8 
sex size ratio 
1.12 
With the exception of the sex size ratio for toothrow length in Mustela 
vison, our values are less in Eira barbara and Grisonella cuja than for 
these variates in the four species of mustelines tested by Zakrzewski, 
suggesting a weaker secondary sexual dimorphism in the tayra and little 
grison. 
Galbreath (1972) suggested the possibility of a chronocline of decreas- 
ing size from T. idahoensis in the lower beds at Hagerman to T. cookii 
and Sminthosinis bowleri in the higher beds, whereas Gustafson 
(1978:39-40) suggested a chronocline of increasing size from T. cookii to 
T. idahoensis based on the relatively small sample of suitable, stratigra- 
phically placed mandibles. The trend shown by Gustafson for the Hag- 
erman beds is suggestive, but far from conclusive, and the evidence from 
other local faunas seems to weaken the case. For example, Gustafson 
assigned his White Bluffs specimen, thought to be very early Blancan in 
age, to T. cookii, but it seems to us to fall more comfortably within the 
variation of the larger T. macrodon, based on his measurements. Also, 
the specimens from the early Blancan Rexroad local fauna are large, and 
the specimen from the Irvingtonian Haile XVI A fauna is small. T. cookii 
and T. macrodon occur together in the late Blancan Broadwater, Sand 
Draw, and Grand View local faunas. Thus, no clear trend of changing 
size through time can be demonstrated on the basis of present collections 
and correlations. In any case, the eastern specimens fall comfortably on 
one side or the other of the indicated specific boundary and thus present 
no problems of assignment. Should all Trigonictis ultimately prove to 
belong to a single heterogeneous species with great individual, sexual, 
temporal, and geographic variation, then T. macrodon would be the 
senior name. 
Beginning with Cope (1868) the fossils now assigned to Trigonictis 
have always been compared appropriately to the modern neotropical 
Galictinae. The complex nomenclatural history of this small group has 
been confusing, and its systematic arrangement remains unresolved. We 
