Cryptopeniculus Philips

Philips, T. Keith & Foster, Douglas E., 2004, Cryptopeniculus nigrosetus n. g., n. sp. (Coleoptera: Ptinidae) from the Namaqualand region of South Africa, Zootaxa 577, pp. 1-11 : 2-5

Cryptopeniculus Philips , new genus

Type species. Cryptopeniculus nigrosetus , new species

DIAGNOSIS. This genus can be recognized by a pronotum with large thick setal tufts in a “V” shape covering most of the surface and composed of thick, strongly recurved or recumbent and approximately parallel setae loosely appressed against and covering pale brown or tan flocculant setae which is sometimes more exposed near the base. There is a distinct longitudinal medial depression between the anterior 2/3 of the pronotal tufts. Additionally, the light to dark reddish black cuticle color, the strongly convex and nearly glabrous elytral surface, and elongate legs are further distinguishing characteristics. There is also a pronounced ridge anterior of the antennal insertions, oriented transversely and obliquely, about the length of the scape and as high as the scape width.

DESCRIPTION. Head: Robust, eyes slightly visible from above, eye approximately rounded, except truncate opposite antennal insertion; vertex slightly convex; cavity beneath eye and laterade of antennal insertion where scape can fit, most depressed at eye base, interantennal space moderately broad, slightly depressed at middle; clypeus posteriorly with strongly pronounced edge; genae expanded laterally; labrum width equal to less than 1/3 head width below eyes, anterior edge rounded; maxillary palp four segmented, labial palp three segmented; antennae filiform, 11 segmented, second antennomere inserted off center of scape near lateral edge; mandible with blunt apex, lacking distinct second tooth, approximately straight externally; mentum triangular, lacking cavity. Thorax: Pronotum strongly convex with two setal peaks on each side of middle, extending posteriorly, fusing at base, setae internally flocculant­like, setae externally elongate, curved with apices converging at crest peak; prosternum narrow, elongate, about 5X as long as wide, extending into mesosternum; mesosternum about as long as wide, about ½ the length of metasternum, anteriorly adjacent to procoxae with transversely flattened, rounded projections extending ventrally; metasternum transverse, broadly emarginate posteriorly; procoxae strongly projecting ventrally, mesocoxae less so, metacoxae flat, distinct, broadly obliquely fused to metasternum. Elytra: Globular; strongly, smoothly convex, distinctly longer than wide; surface predominantly glabrous, punctures small, shallow, very indistinct, arranged in longitudinal rows; lateral edge of basal half with a distinct carinae above epipleura, extending opposite pronotal base through to middle; basal constriction interrupted by several short longitudinal carina forming pockets. Ven t ri te s: All sutures clearly visible, lengths of 2nd–4th ventrites even throughout width except slightly longer laterally; 4th distinctly longest; 3rd and 4th subequal. Legs: Elongate, apically capitate, femora at basal half narrow, abruptly expanding around middle, tibia narrow, gradually increasing in length from base to apex, as long as respective femora except metatibia longer than metafemor; 1st and 5th tarsomere moderately long, 2nd through 4th distinctly shorter.

ETYMOLOGY. The generic name is derived from Greek adjective for hidden (crypto) and the Latin noun for a brush or sponge (peniculus) in reference to the flocculant like setae on the pronotum which are largely obscured by dark elongate setae overlain on the surface of the former.

REMARKS. Like many of the spider beetle species where both sexes are flightless, it is difficult to determine the sex without a dissection unless the genitalia is partially extruded from the abdomen. Although the pronotal shape is unique to this species, it is approached in form by several species representing a second undescribed genus. Cryptopeniculus can easily be separated from this group by a broad, rather than narrow and ridge­like, interantennal space. Additionally, the nearly impunctate and glabrous elytra of Cryptopeniculus is in sharp contrast to the that of second new genus which has longitudinal rows of deep punctures, the more typical ptinine setal rows formed of recumbent and erect setae, and the presence (usually) of humeral and apical setal maculations.

RELATIONSHIPS. This genus is one of a wide variety of flightless species found in South Africa and in many other parts of the world. Precise relationships may be obscured by the evolution of features associated with flightlessness which adapt this species and so many others for a scavenging lifestyle in usually xeric habitats (see discussion in Philips 2000). Morphological traits include the very convex shape of the elytra, reduced elytral setation, loss of wings, and fusion of the metacoxae to the metasternum.

Cryptopeniculus may represent a clade outside the lineage of species recognized by some as the Gibbiinae (e.g. Bellés 1985) or the Gibbium species­group ( Bellés 1982). Possible convergent similarities between these clades include the flocculant pronotal setae and the smooth globular elytra found in both Cryptopeniculus and gibbiines such as Mezium . Alternatively, it might be one of the basal lineages of the Meziini sensu Bellés (1985).

Based on limited distributions of the southern African taxa, it is likely that most if not all of these originated in this region, including this new species and, for example, the taxa of Damarus found in the coastal areas of adjacent Namibia. Some of these generic level clades are obviously closely related based on a large number of synapomorphies (which will be investigated in a later study). But for many other taxa, which look superficially like species of Ptinus , it remains unknown if there is either a single common ancestor or if many separate origins (which we hypothesize as most likely) were involved in creating the incredible diversity of spider beetles known from this region.