Why are there no Whipspider records from Namibia?

Rock crevices and caves. Also under bark and stones. Presumably the same as for the KZN and Savanna species - which are reasonably well recorded.
I seem to recall that the new one (?? D. sylviae) - all the specimens were from road building and mining.

Endemism of Arachnida (Amblypygi, Scorpiones and Solifugae) in the highlands and escarpments of Angola and Namibia: Current knowledge and future directions L Prendini & TL Bird December 2023 https://www.nje.org.na/index.php/nje/article/view/volume8-prendini

Highland endemic whip spiders
Only two species of Amblypygi may be considered endemic to the highlands and escarpments of Angola and Namibia

.* Phrynichodamon scullyi (Purcell, 1902), of the family Phrynichidae Simon, 1892, has been recorded from only four localities in southwestern Namibia, each represented by a single individual [Hakosberge, Tirasberge, Naukluft and Aus Mountains]. Most of the known records ... occur further south, in the Kamiesberg, Bokkeveldberge and Cederberg ...
.* Xerophrynus machadoi (Fage, 1951), considered incertae sedis within superfamily Phrynoidea is known from fewer than 10 localities, two (the type and Omahua) in sw Angola and in nw Namibia (valleys on the southern slopes of the Brandberg Massif, Etendeka and Otjikondavirongo mountains, with Huab Uis (Damaraland) Mountains as isolates. ... the large distances between the disjunct populations ... emphasise the need for genetic comparison to assess whether more than one species is involved, as well as to determine the timing of divergence.

The difficulty of collecting these secretive lithophilous arachnids, which appear to retreat into deep rock crevices or exfoliations during the dry season, implies that collection efforts must be focused on the rainy season, and concentrated on areas with higher humidity, such as caves, wells and watercourses, for any possibility of success.

.* Damon gracilis Weygoldt, 1998, a third species .... endemic to southwestern Angola and northwestern Namibia, has been recorded from some highlands and escarpments, including the Serra da Neve in Angola and the Baynes–Otjihipa Mountains in Namibia ... majority of the known records are situated at low elevation, often in association with wells and watercourses.
.* Damon sylviae Prendini et al., 2005, the fourth species of whip spider recorded in Namibia, has not been recorded from the highlands and escarpments