A reliable, if difficult character that distinguishes adult males and females of Monogynaspida from other Mesostigmata is the absence of an intercalary scleritesclerite:
A component section of an exoskeleton; a plate forming the skeleton of an arthropod.
between the basitarsusbasitarsus:
a basal subdivision of the tarsus.
and telotarsustelotarsus:
(= acrotarsus, apicotarsus) a distal division of the tarsus. 
on leg IV. This scleritesclerite:
A component section of an exoskeleton; a plate forming the skeleton of an arthropod.
and its pair of ventral setaeventral setae:
in the Lindquist-Evans system used in the Mesostigmata, the ventral region has up to three longitudinal rows (Jv, Zv, Lv) with 1-5 transverse row designations.
is present in Holothyrida and Ixodida as well as Sejida and Trigynaspida in the Mesostigmata.
Author: David E. Walter
Content last updated Sept. 2006, unless indicated otherwise
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