(Figs. 18, 19, 98)

Type Material. Holotype (male): South Africa: Eastern Cape Province, Sundays River system, Letskraal, river, 32° 5' S, 24° 49' E, 13 July 1967 (RSU 10.1). Deposited in the AMG.

Differential Diagnosis. Members of P. retinaculus are similar in size and dorsal sculpture to members of P. semiplanus (Figs. 15, 18), but are distinguished therefrom by the shorter elytra, and males by the aedeagi, which are quite dissimilar in the two species (Figs. 19, 21). Females of P. retinaculus are not yet known.

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.73/0.67; head 0.29/ 0.45; pronotum 0.38/0.54; elytra 1.08 /0.67. Dorsum piceous to black, maxillary palpi, legs and venter dark brown. Submentum and mentum microreticulate, dull, sparsely punctulate.

Head with labrum very finely, very sparsely punctulate, shining. Clypeus entirely and frons on disc shining, finely sparsely punctulate, punctures separated by about 2–8xpd, size of largest punctures less than 1xef. Frons microreticulate laterally and in deep anteocellar sulci. Ocelli distinct.

Pronotum cordate, widest in front of middle; anterior angles obtuse, posterior rectangular; sides finely margined, weakly crenulate; anterior margin shallowly arcuate over median 2/3, with narrow hyaline border; discal reliefs strongly shining, very finely, very sparsely punctate, interstices ca. 4–8xpd; anteriorly and posteriorly punctures much larger, about 2xef; with foveae as follow: median anterior elongate and smaller posterior, not confluent; a small anterior and larger oval posterior admedian; and a large anterior and small deep posterior adlateral on each side; foveae punctate, not microreticulate; punctures on discal reliefs without discernible setae.

Elytra non­carinate, parallel­sided or nearly so, apices conjointly rounded; sutural apices rectangular; sides smooth, weakly explanate; posterior declivity rather gradual. Serial punctures moderately large and deep, on disc slightly larger than largest pronotal punctures, interstices on disc about 1xpd, or less; punctures becoming progressively smaller over posterior declivity; without granules. Series one striate­impressed, more strongly in posterior 1/2 than anterior 1/2. Intervals very weakly rounded, width on disc about 1–2xpd. Most punctures without discernable seta.

Metaventral disc rather flat, with shallow midlongitudinal impression in basal 1/2. Thoracic ventrites and abdominal ventrites 1–5 clothed with dense setae except glabrous midlongitudinal prosternal ridge, glabrous dull mesoventral plaques and small glabrous inverted V­shaped basomedian area on metaventrite in front of intercoxal sternite. Ventrite 6 shining, with sparse setigerous punctures across distal 1/2.

Aedeagus length of main­piece ca. 0.35 mm; flagellum very long, coiled; main­piece sinuate in ventral view, left side markedly arcuate (Fig. 19).

Etymology. Named in reference to the long, coiled aedeagal flagellum.

Distribution. Currently known only from the type locality, Letskraal, Eastern Cape Province (Fig. 98).