Five new species are described from Paraguay: Xeranobium paraguayense sp.n. (subfam. Anobiinae), Byrrhodes densepilosus, Calymmaderus aguilari, C. depilis, C. kochalkai spp. n. (subfam. Dorcatominae).
All name-bearing types of species are deposited in the Museo National de Historia Natural del Paraguay – NMHNP.
Dorsal surface of X. paraguayense is brownish-black, ventral surface is black. Pubescence very dense, silvery, very fine, nearly appressed. Eyes separated by 1.1 (male) to 1.5 (female) eye diameters. Antennae 11-segmented, with 3-segmented club. Segments 5 to 8 (funicle) are serrate, transverse, without rami; segments 9 and 10 (club) elongated and with tooth. Pronotum in average 1.3 times as wide as long; its disc a little convex; lateral margin distinct only on the basal third of pronotum. Elytra 1.8–2.1 times as long as wide, with punctate striae. Interstriae are 1.5 times as wide as striae. First and second abdominal sternits merged in the centre. Armaments of the internal penial sac as shown in Fig. 1.7. Length 3.9–5.5 mm. The new species differs from the other species of this genus described by Fall (1905) and by White (1971) by serrate antennal segments, very dense and fine silvery pubescence, and by the armaments of penial sac.
B. densepilosus. Dorsal surface black, ventral surface brown excepting red abdomen. All surface covered with very short and very dense pubescence; which is silvery on dorsal surface and golden on the ventral one. Each elytron with glabrous spot on the middle. Body strongly convex. Eyes are of irregular form, elongated, flat, their lower margin with notch. Eyes separated by 1.3 longitudinal eye diameter. Antennae of 9 segments, with 3 segmented club. Pronotum 1.27 times as wide as long. Anterior angles acute and recurved under head. Punctures very dense and they are larger on the anterior angle end than on pronotal middle. Elytra 1.2 times as long as wide and 2 times as long as pronotum. Disc with thin striae, sides with 3 deep striae. Two lower lateral striae formed with conjugate puncture rows. Metasternum with uniform punctation on the middle and with dual punctation on sides. Visible abdominal sternites not merged. Length 3.75 mm. The new species differs from other Byrrhodes by unusual pubescence.
C. aguilari. Beetle blackish brown, covered with dark grey, fine, appressed pubescence arranged in spots. Body twice as long as wide. Frons with transverse pecten, under the latter there is a fossa; upper half of frons has longitudinal folds. Surface with large punctures. Eyes separated by 1.6 longitudinal eye diameter. Antennae 11-segmented, with 3-segmented club. Pronotum 1.3 times as wide as long. Anterior margin slightly suberected. Acute angles strongly recurved under head. Punctation dual. Elytra 1.6 times as long as wide and 2.36 times as long as pronotum, with 2 lateral striae in apical half of elytra. Metasternum with deep longitudinal median stria. There are transverse fossae on either side of median stria in proximal half of metasternum. Punctation dual on the middle of metasternum, large punctures separated by 1–3 puncture diameters. Aedeagus curved dorso-ventrally. Internal penial sac with more than ten transverse spines. Length 4.0 mm. C. aguilari differs from other species of this genus by form of frons (with transverse pecten), transverse fossae on either side of median striae on metasternum, and armaments of penial sac.
C. depilis. Elytra black, antennae, pronotum, metasternum brownish, head and abdomen reddish, tibiae and tarsi yellow. Beetles glabrous, shining. Frons with angular prominence, with dense, fine punctation. Eyes a little oval, separated by 1.2 (male) to 2.0 (female) vertical eye diameters. Antennae 11-segmented; three last segments are large, broad; segment 9 is the longest, segment 11 is short and rounded in female, elongated and acuminate in male. Pronotum 1.6 times as wide as long, without bulgings. Acute angles recurved under head. Punctures separated by 2–3 puncture diameters on disc, and one puncture diameter on sides of pronotum. Elytra about 1.3 times as long as wide and 2.1–2.2 times as long as pronotum, with 2 lateral striae; upper stria does not reach the base of elytra. Punctation sparse on disc and denser on sides and apex of elytra. Anterior margin of metasternum with furcate bidental process, distal half of metasternum with groove. Process with very dense, large punctures, the remaining part of metasternum with sparse, fine punctures. Tibiae and tarsi thin. Segment 5 of the hind tarsus is twice as short as the 2nd one. Length 2.3–2.7 mm. This species differs from others Calymmaderus by glabrous surface, and large, dense punctation on anterior process of metasternum.
C. kochalkai. Body black, narrowing to the end. Pubescence yellowish-greyish brown, appressed; near elytral suture directed obliquely from suture. Body about 1.9 times as long as wide. Lower part of frons has longitudinal carina and transverse fossa under it. Eyes separated by 1.8 longitudinal eye diameter. Antennae 11-segmented. Club consists of three flat segments. Pronotum 1.3 times as wide as long, without bulgings. Anterior margin slightly suberect. Acute angle recurved under head. Punctation dual, large punctures separated by one puncture diameter on disc, and 1–2 diameters on sides of pronotum. Pubescence parted to two sides on apical part of pronotum. Elytra 1.3 times as long as wide and 2.3 times as long as pronotum, with two lateral striae. Upper stria neither reaches the elytral base nor elytral apex. Row of large punctures runs along above upper stria. Surface with dual punctation. Anterior furcate bidental process of metasternum is short. Metasternum with oblique prominence on either side of median groove. Surface with dual punctation; large punctures separated by one puncture diameter. Length 3.0 mm. C. kochalkai differs from other species of this genus by form of metasternum: short anterior process and oblique prominence on either side of the median groove, and also form of frons with carina and transverse fossa above clypeus.