Purealus, Anderson, Robert S., 2018

Anderson, Robert S., 2018, Purealusbeckelorum, a new genus and species of cleonine weevil from western Texas and eastern New Mexico (Coleoptera, Curculionidae, Lixinae, Cleonini), ZooKeys 785, pp. 1-10 : 1

Purealus gen. n. Figures 1-3, 4-7, 8

Type species.

Purealus beckelorum sp. n. by present designation.

Diagnosis.

Cleonini with body form moderately robust, rostrum medially longitudinally tumescent with dorsal contour in lateral view evenly rounded, procoxae widely separated, base of elytral interval 3 distinctly tumescent and asperate.

Description.

Size. Moderately large, body length 7.8-9.4 mm (exclusive of head and rostrum), moderately robust in body form. Mouthparts. Prementum rugose, concave medially, carinate laterally, with 2-3 large and 2-3 smaller setae on each side, a pair of long setae towards middle at apical margin. Maxillary and labial palpi not externally visible. Rostrum. Robust, longitudinally medially tumescent, dorsal contour in lateral view distinctly arched, rounded. Median tumescence low, not evident as distinct carina. Epistoma slightly swollen, produced anteriorly, with apical margin very slightly, very broadly, apically emarginate. Antenna with funiculus with article I subequal in length to, to slightly longer than, article II; club of four articles, apical three articles of club with placoid sensillae. Head. Eye elongate teardrop shaped, slightly prominent, not convex dorsally. Area behind eye with shallow irregular punctures. Upper margin of eye rounded, frons convex especially at base of median rostral tumescence. Vestiture. Dorsum with suberect or erect vestiture short and sparse; with simple very elongate-narrow recumbent white hair-like scales of variable size and density. Prothorax. Dorsal surface of pronotum coarsely punctate. Pronotum with median basal area deeply impressed towards basal margin; anterolateral margin, behind eyes, with moderately developed rounded postocular lobe; postocular vibrissae short, of equal length; disk with elongate white larger moderately dense scales present in lateral sinuate stripe, variously larger and denser along lateral margins; median area largely black in color, underlying black cuticle not obscured by any scales, subglabrous. Prosternum with very slight impression anterolaterad of each procoxal cavity; without any swelling immediately anterior to each prosternal impression; procoxae widely separated by about one-half width of coxa by globular posterior process of prosternum. Legs. Foretarsus moderately broad, articles II and III more or less subequal in length, at most only slightly longer than broad; article I longer than articles II or III; article III deeply bilobed. Meso- and metatarsus very slightly more elongate-narrow, article II slightly to distinctly longer than article III; article I distinctly longer than articles II or III; article III deeply bilobed. Ventral tarsal pilosity reduced to some extent (not covering entire ventral surface of a tarsal article) to almost lacking entirely from at least more basal tarsal articles (especially of metatarsus). Claws connate from near base to through basal one-third, slightly to markedly divergent. Foretibia with inner margin lacking denticles; near apex with second spur not developed. Tibia with corbel ridge rounded. Hind wings. Absent. Elytra. Intervals, except humerus and bases of intervals 3, 5, 7, and 9 flat, bases of intervals 3, 5, 7, and 9 slightly to markedly swollen, asperate (especially that of interval 3 which is tumescent). Striae confused, punctate. Humeri rounded. Scales variously condensed in patches of larger, denser white scales. Abdomen. Ventral surface almost uniformly covered with fine dense white hair-like scales. Abdominal sternum VII in males with apical margin at middle simple, without small dorsally directed median tooth. Genitalia. Female. Abdominal sternum VIII lacking basal arm (spiculum gastrale). Gonocoxite II elongate triangular in form, apex not prolonged into lobe; stylus present, moderately large in size; apical. Spermathecal gland oval. Symbiont pouches elongate-oval lying adjacent to vagina, composed of 10-12 rings, joined to vagina near apex. Male. Abdominal sternum VIII with interior angle of each sclerite lacking basal projection. Aedeagus moderately robust, in lateral view more or less evenly arcuate throughout length; apex not spatulate, somewhat acuminate. Internal sac not everted. Apical sclerite complex not evident.

Derivation of generic name.

The generic name Purealus is derived as an anagram of Apleurus. Gender masculine.

Natural history.

Five specimens of this species were collected in October 2004 at McKenzie Lake, Gaines County, Texas by tiger beetle enthusiast Dave Brzoska while hunting tiger beetles. The exact circumstances of capture are not known but the specimens were likely walking around on the ground in areas inhabited by tiger beetles. One specimen was collected dead by me in fine debris and other insects washed up along the northern shore of McKenzie Lake in October 2016. Another three specimens were collected in Lea and Quay Counties, New Mexico, walking on the ground. During my trip to McKenzie Lake numerous species of shrubs and herbs were searched for this species without success. Searches of tiger beetle habitats such as open sandy flats, open alkaline areas around the lake, and dirt roadways also yielded no specimens.

Comments.

The robust form, robust, medially longitudinally tumescent rostrum with dorsal contour in lateral view evenly rounded (Fig. 2), but especially the widely separated procoxae (Fig. 3) and the distinctly tumescent and asperate base of elytral interval 3 (Figs 1-2), will readily distinguish this genus among all Cleonini . Such widely separated procoxae are apparently not known in any other world Cleonini , all of which have the procoxae contiguous. The genus combines characters of the North American genera Apleurus Chevrolat and Scaphomorphus Motschulsky with the rounded tibial flange and rounded postocular lobes of Scaphomorphus but the robust rostrum, reduced ventral tarsal vestiture and more robust form of an Apleurus . Characters used to recognize the monophyly of Scaphomorphus (shiny glabrous median tubercle at base of abdominal sternum VII in female) and various groups of Apleurus (blunt tooth at apical margin of abdominal sternum VII in male, swellings anterior to front coxae, apically rounded epistoma) are not present in Purealus .