The posterior margin of the nuchal plate is slightly embayed and has a single posteromedian
process (Figs 2B, 6A).
The only Patagonian species of Stilobezzia (Acanthohelea) in which males have the gonostylus abruptly curved and the gonocoxite has a conspicuous protuberance on proximal inner margin; females have two large, greatly elongated flask-shaped spermathecae and sternite 8 with a U-shaped posteromedian
Fore femur with three strongly developed posterodorsal setae, median seta being considerably stronger than supramedian and posteromedian
setae; three preapical dorsal setae, two median dorsal setae, 10 posteroventral setae evenly spaced on femur, no differentiated posterior setae.
Surface of mesoscutum distinctly shagreened peripherally, smooth and polished posteromedially; punctatorugose except the small shiny posteromedian
area, here punctures separated by 1 to 2 puncture diameters.
Anal segment of males tectiform and with a wide triangular posteromedian
excavation, posterior margin set with numerous incurving teeth ventrally and occasionally the posteroventral angle expanded.
53 x as long as broad, lateral lobes of pygophore in ventral view very slightly projected posteriad, apices conical, ventroposterior margin medially V-shaped, posteromedian
lobes on either side dorsally prominent, also clearly visible in lateral aspect.
Anteromedian sulcus moderately deep, ovate; posteromedian
sulcus narrow, shallow anteriorly, deep posteriorly; posterolateral sulci shallow, wide, curved; posteromarginal sulcus deep, narrow.
8O): Median notch less deep with seven pairs of plumose setae and one posteromedian
The unworn anterior loop is highly complex in that the summit is formed "by a large irregular posteromedian
tubercular eminence from which a number of furrows or little valleys radiate, descending obliquely to the outer, anterior, and inner borders of the loop.
The anterior, lateral and posterior margins of syntergite I-III, the fusion lines between mediotergites I-II and II-III, the posterior and lateral margins of mediotergites IV-VI, the lateral margins of mediotergite VII, the posteromedian
angles of epipleurites II-VI, and the posterior margins of all visible abdominal sternites are conspicuously elevated, and ornamented with setigerous tubercles.
Only species of Stilobezzia (Acanthohelea) from Patagonia with the male sternite 9 bearing an elongate and narrow posteromedian
89 times longer than pronotum and vertex combined; 3 longitudinal carinae all reaching anterior and posterior margins, median carina indistinct on posteromedian
area, which bears transverse striations.