Revision of the Milliped Genus Scytonotus Koch 
(Polydesmida: Polydesmidae) 
Rowland M. Shelley 
North Carolina State Museum of Natural Sciences 
P.O. Box 29555, Raleigh North Carolina 27626-0555 
ABSTRACT — The milliped genus Scytonotus occurs in four regions 
of North America, one east of the Central Plains, and three west 
of the Continental Divide: from northern Utah to northeastern 
Idaho and northwestern Wyoming; from southeastern Washington 
and western Montana to southeastern British Columbia; and along 
the Pacific Coast from San Francisco Bay and the northern San 
Joaquin Valley to the northern extremity of the Alaskan panhandle, 
including all offshore islands except the Queen Charlotte Islands. 
Three of the nine component species occur in the East — S. granulatus 
(Say), broadly distributed across most of the area, and S. virginicus 
(Loomis) and S. australis Hoffman, both endemic to the Blue 
Ridge province. Six occur in the West — S. insulanus Attems and 
S. bergrothi and simplex, both by Chamberlin, inhabiting the Pacific 
Coastal region; S. inornatus new species, in the eastern Cascade 
foothills of southern Oregon; S. columbianus Chamberlin, in the 
interior of British Columbia and northeastern Washington; and S. 
piger Chamberlin, south of the International Border from Idaho to 
Utah. Polydesmus amandus Chamberlin and S. orthodox Chamberlin 
are placed in synonymy under S. piger, and S. michauxi Hoffman 
is reduced to a subspecies of S. virginicus. Taxonomic characters 
primarily involve the configurations of the medial, distal, and lateral 
laminae of the gonopodal endomerite and its length relative to 
the tibiotarsus. Except for S. columbianus, virginicus, and australis, 
the paranota of segments 5-9 of adult females are vestigial or 
absent, and the tibiae of legs 13-20/22 in males possess distal 
lobes on the anterior and/or caudal margins; the arrangements and 
sizes of the latter vary among the species and may hold taxonomic 
utility. Three lineages or species groups are recognized: the granulatus 
group, comprised of five species with teeth on the inner margin 
of the distal lamina; the bergrothi group, composed of three species 
in which the distal lamina is prolonged; and the monobasic inornatus 
group, in which the structure is unmodified. Relationships among 
the lineages are hypothesized as inornatus + ( bergrothi + granulatus ). 
Anatomical and distributional evidence point to the Cascade Mountains 
of southern Oregon as the primary source area, and a secondary 
center of evolution exists in the Blue Ridge Mountains of North 
Carolina and Virginia. Pertinent anatomical illustrations and dis- 
tribution maps are presented along with complete synonymies, 
diagnoses, and a key to species. 
Brimleyana 19:1-60, December 1993 
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