Pachysandalus schoutedeni Villiers, 1962

Swanson, Daniel R., 2019, Doomed to a vile lot: new taxa, notes, and an updated generic key for the Old World corsairs (Heteroptera: Reduviidae: Peiratinae), Zootaxa 4700 (2), pp. 196-228 : 207-209

Pachysandalus schoutedeni Villiers, 1962

( Fig. 9 )

Pachysandalus schoutedeni Villiers, 1962: 465 . Pachysandalus schoutedeni Villiers, 1962 is one of three species currently comprising the genus Pachysandalus Jeannel, 1916 , the other two being Pachysandalus collaris Jeannel, 1916 and Pachysandalus orientalis Jeannel, 1916 . The genus is precinctive in eastern Africa.

Material examined: SUDAN: Upper Nile , nr. Malakal, 5–20 January 1963, Linnavuori, Pachysandalus collaris [no determiner], det. D. R. Swanson 2019, AMNH _ IZC 00321076 [1 male] ( AMNH) [imaged] ( NEW COUN- TRY RECORD) .

Remarks: The specimen bears a label stating “Purchased by AMNH from R. Linnavuori”. It seems likely that the series represented by this specimen are those reported from Sudan as P. collaris by Linnavuori (1974). However, the color pattern and size are a better match for P. schoutedeni : the corium is pale only at the base and the meso- and metafemur are apically dark in P. collaris . Furthermore, P. collaris is based on a female of length 8.47, whereas the examined male is 10.1 mm in length. This is problematic, because in peiratines, and indeed most reduviids, females are larger than males.

Difficulty in identification of species of Pachysandalus is not surprising. Villiers’ (1962) key will not work as the characters of couplet #1 are almost certainly based on sexually dimorphic characters (the eye is larger and thus the “temple” is smaller in males) and Coscarón’s (2002) revision dilutes Villiers’ character in couplet #2, as she described both with anterior lobe “dark brown” and posterior lobe “light brown”. Coscarón’s (2002) own key is inadequate, leaving out opposing characters and including a potentially sexually dimorphic one (i.e., ocelli on tubercle) and a potentially intraspecifically variable or insignificant one (i.e., scape coloration: yellowish vs. light brown vs. dark brown).

There also are discrepancies in the measurements of body length, which Coscarón (2002) does not address. For example, Jeannel (1916) gave the length of P. collaris as 19 mm, whereas Coscarón (2002) indicated this length to be 8.47 mm. Admittedly, this one is easily explained away by an erroneous extra “1” in front of the “9” in Jeannel’s (1916) original description. Jeannel (1916) also gave the length of P. orientalis as 8 mm, whereas Coscarón (2002) indicated this length to be 9.51 mm. Villiers (1962) gave the length of P. schoutedeni as 8 mm; yet, Coscarón (2002) indicated this length to be 6.63 mm. It would be easier to accept Coscarón’s (2002) measurements as corrections, if she had acknowledged the conflicting data. As it stands, new measurements corroborating one account or another are necessary.

I have gleaned from both Villiers’ (1962) and Coscarón’s (2002) accounts, plus Jeannel’s (1916) original descriptions, a new key to Pachysandalus , based largely on color pattern. The key is provisional as I have examined only the single male specimen included herein. Given the median process of the pygophores ( Coscarón 2002, figs. 26, 28), it appears that at least P. orientalis and P. schoutedeni are distinct, but, as these color characters easily form a continuum, it remains to be seen whether P. collaris represents the female of one of these other two species.

Figures

FIGURE 9. Pachysandalus schoutedeni, adult male: (A) dorsal habitus; (B) lateral habitus. Scale bar =2 mm.