A new labidostomid from Australia 
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may be related to immature sclerification (neoteny 
in the common sense of maintenance of pre-adult 
characters in adult stases). These characters are 
found in both subgenera, Selltiickiella and 
Dicastriella. The subgenus Selltiickiella also exhibits 
the peculiar morphology of the famulus (dorsal 
regressive seta of tarsus I), with two unequal 
branches which is unique among species of 
Labidostomidae. This morphology results from a 
regressive evolution with the complex primitive 
famulus being present in Labidostoma (Grandjean 
1941). 
Sellnickiella (Selltiickiella) biunguiculata sp. nov. 
Material Examined 
Holotype 
2, Dwellingup, Western Australia, Australia, 
32°43'S, 116°04'E, 8 June 1978, pitfall traps, S.J. 
Curry (WAM 93/96). 
Paratypes 
Australia: Western Australia: 1 2, 1 <?, 
Dwellingup, 32°43'S, 116°04'E, 8 June 1978, pitfall 
traps, S.J. Curry (WAM93/37-38); 4 $, 3 2, Mt 
Cooke, 32°25'S, 116°18'E, 27 April 1992, leaf litter, 
M.S. Harvey, J.M. Waldock (WAM 93/39-45). 
Diagnosis 
Sellnickiella (S.) biunguiculata is very similar to S. 
(S.) ivomersleyi (Atyeo and Crossley) from South 
Australia, but can be distinguished by the 
bidactylous tarsi II—IV, the absence of lateral 
projections on the anterior edge of dorsal shield, 
the ornamental pattern of dorsal shield, and 
characters of the fixed digit of the chelicera, which 
is serrate and bears a strong blade. 
Description 
General Morphology (Figure 1) 
Small elongated, long legged species, yellow to 
brown in alcohol. Leg I length similar to body 
length: dorsal shield ca. 600 to 650 pm, somewhat 
oval; chelicerae strong, ca. 150 pm in length; their 
strong digits come into view in dorsal examination 
before frontal extremity of dorsal shield beneath a 
small median eye (20 pm diameter). Dorsal shield 
(Figure 1A) bears usual pairs of setae with pairs ga, 
gr, ge gm and trichobothria boa and bop belonging 
to the aspidosoma, 1 6 lacks one pair, ge, as in S. 
ivomersleyi [see Atyeo and Crossley (1961)], dorsal 
and lateral files (la) to (le) and (da) to (de) on the 
opisthosoma. 
Trichobothria long (more than 100 pm) with thin 
ciliation longer on anterior pair, which is inserted 
very close to anterior edge of dorsal shield. 
Distance between bases of anterior pair is 140 to 
150 pm while in the posterior pair this distance is 
160 to 180 pm. Anterior pair (ga) inserted ventrally. 
Cuticle regularly alveolated except in dorsal part 
behind level of lateral eyes where ornamentation is 
dissolved into a tiny punctated U-shaped area 
whose internal margins are limited by setae (gm) 
Figure 2 Sellnickiella (Sellnickiella) biunguiculata sp. nov: A, chelicera, antiaxial view; B, infracapitulum and palp, 
ventral view; C, anterior part of dorsal shield, lateral view; D, ocular zone of dorsal shield, lateral view. 
