Genus Acutaspis

Ferris, 1941

Appearance in life
Scale cover of adult female more or less circular, flat, with central or subcentral exuviae. Scale cover of immature male similar to female but smaller and slightly elongate.

Adult female not pupillarial; body circular or pyriform; prosoma usually membranous but sometimes slightly sclerotized towards margins; often with a sclerotized prepygidial marginal spur or protruberance on each side, slightly anterior to the posterior spiracles; pygidium with a central flask-shaped sclerotized area arising from the apical area between the third lobes and boadening laterally about on a level with the anus. Pygidium with apical half strongly acute, angle subtended by apex less than 90°; margin sclerotized; with 3 pairs of well-developed unilobulate lobes. Lobes short; median lobes rounded, often wider than long, smaller than short, wide second lobes that may be notched on outer side; third lobes wider than second lobes, often with outer margin notched or serrated. Slender paraphyses, longer than the nearest lobe, the longest being somewhat clavate, arising from bases of lobes and between second and third lobes; also shorter paraphyses arising from sclerotized margin beyond the third lobe. Plates extremely minute, usually fringed, confined to interlobular spaces but sometimes absent from between median lobes or entirely. Anus oval, much longer than median lobe, situated posterior to centre of pygidium; vulva situated between centre and anterior third of pygidium. Dorsal macroducts usually extremely long and slender; usually 1 marginal duct between median lobes, 1 between median and second lobes, 1 between second and third lobes and 2 between third lobe and position of the fourth lobe on either side, also a series present anteriorly along the sclerotized pygidial margin; submarginal ducts usually arranged in 3 distinct poriferous furrows between segments VIII and VII, VII and VI and VI and V on each side, the lateralmost furrow extending as far forward as, or anterior to, the anus. Prepygidial marginal ducts often present. Perivulvar pores present in 4 groups. Stigmatic disc pores absent; antennae situated fairly near mid-line, each bearing one seta.