1974] 
Coyle — Genus Aliatypus 
433 
Figure 1: Suggested phylogeny of Aliatypus species. 1. Character 
states of hypothetical ancestral stock: No ICS keel or OCS keel. Seminal 
receptacles with moderately long, sinuous, non-tapering stalks and medium 
sized bulbs. Posterior sigilla small and well separated. Legs of moderate 
length. Thoracic groove a deep pit. Leg I setation as in majority of 
species. Moderately lar,ge body. 2. Seminal receptacle stalks become 
short and straight. Legs become proportionately shorter. 3. Posterior 
sigilla enlarge. Thoracic groove lost. Leg I setation changes. 4. Pos- 
terior sigilla enlarge. Legs become proportionately shorter. Become adapted 
to dryer habitats. 5. Become adapted to more humid and cooler habitats. 
6. ICS keel develops. 7. Seminal receptacle stalks become tapered. 8. Con- 
ductor tip changes form. Body size reduced. 9. Seminal receptacle stalks 
become less elongate and less sinuous. Body size reduced. 10. Body size 
reduced. 
meant to be a useful working hypothesis, subject to revision. Char- 
acters which were relied upon most heavily are palpus form, seminal 
receptacle form, and posterior sigilla size and placement. The actual 
direction of evolution in some characters may well be the reverse of 
those suggested. It is certain that Aliatypus contains two distinct 
groups of closely related species — A. calif ornicus, A. janus , A. iso- 
latus, A. aquilonius , and A. gnomus on the one hand and A. tro- 
phonius, A. erebus , A. plutonis, and A. torridus on the other — and 
two distinct species, A. gulosus and A. thompsoni , each rather dis- 
tantly related to all the others. 
