Lepanomus Balfour-Browne, 1945

Wanat, Marek, 2021, New basal taxa of South African Apioninae (Coleoptera: Curculionoidea: Brentidae), Zootaxa 5035 (1), pp. 1-60 : 35-37

Lepanomus Balfour-Browne, 1945

Type species: Lepanomus crinalis Balfour-Browne, 1945 (by original designation and monotypy).

Diagnosis. Medium-sized species, body 3.0– 3.6 mm long. Long erect setae, truncate or finely emarginate apically, present on all body parts including femora and tibiae, on body dorsum accompanied by relatively dense, appressed or semi-recumbent light pilosity, on elytra irregular and condensed into numerous small patches. Integument of elytra with median crescentic yellowish mark ( Fig. 187 ). Rostrum inserted in upper part of head profile, less than 1.55 × as long as wide; scrobes broadly separated, their septum strongly raised anteriorly, on rostrum profile seen as obtuse ventral tooth situated exactly at the level of antennal pits ( Fig. 197 ). Antennae 0.5–0.6 × as long as elytra and 1.4–1.6 × as long as pronotum, with only 3 proximal segments of funicle evidently elongate; scape about as long as funicular segments 1+2; club large, loosely segmented, obtuse apically, about 4 × as long as wide. Pronotum weakly trilobate, with rectangular hind corners; its subapical constriction deeper than obsolescent sub-basal one; disc punctate, with elongate median fovea, without basal flange; sub-basal transverse line obliterated ( Figs. 188 , 200 ). Elytra with suture apically straight and simple ( Fig. 207 ); their bases with obsolescent rim vanishing at level of stria 5; five striae present between suture and humeral callus; stria 1 shortened, commencing well behind scutellar shield; only subapical remain of separate stria 10 present; striae apically joining (1+10)+(2+9), 3+8, 4+5, 6+7 ( Fig. 205 ). Mesocoxae separated mainly by long process of mesoventrite; mesocoxal cavities with complete, narrow posterior rim. Legs robust, all sub-equally long. Procoxae pear-shaped; both pro- and mesocoxal dentiform processes low, but evident. Trochanters shortly elongate ( Fig. 204 ). Femora unarmed, with fine transverse wrinkles, entire surfaces with protruding setae. Tibiae lacking sharp edges, with long erect setae on outer side and expanded apical tuft ( Fig. 196 ).

In male, only meso- and metatibiae with mucro; pygidium concealed, with short anterior apodemes and no trace of apical ridge ( Fig. 215 ) nor tongue-like internal process; no additional sclerites in membrane between sternites VIII and IX; sternite VIII peculiar, divided into broadly separated hemisternites ( Fig. 222 ); sternite IX with asymmetrical fork; tegminal plate with large, well delimited fenestrae; apex of pedon canaliculate; endophallus without typical frena, instead with pair of narrow, bar-like sclerites. In female tergite VII broadly truncate, not carinate along apical margin; tergite VIII divided to hemitergites.

See also the key to South African genera below.

Redescription. Body length 3.0– 3.6 mm. Erect setae on elytra mixed piceous-black and cream-white, on head, pronotum and legs solely light. Appressed creamy piliform scales or setae dense, distinctly shorter than elytral interval’s breadth, on head forward-directed, on pronotum centripetal on sides and forward-directed along mid-line ( Fig. 188 ), on elytra condensed into inconspicuous tuft at base of interval 3 and aggregated into numerous, irregularly disposed small patches along all intervals. Integument piceous-black except dark-testaceous antennal scape and funicle, on elytra with additional, variably long lighter markings between median crescentic mark and base, usually ranging over intervals 2–3 and occasionally even confluent with the median mark; additional small yellowish patch constantly present on interval 3 at end of elongate submedian elevation at beginning of elytral declivity.

Morphological indices (n=10): rl/pl: 0.60–0.64; rl/mxrw: ♂ 1.34–1.38 (M: 1.35), ♀ 1.42–1.52 (M: 1.47); scl/ msrw: ♂ 0.43–0.52 (M: 0.47), ♀ 0.52–0.54 (M: 0.53); msrw/mtrw: ♂ 1.11–1.12 (M: 1.12), ♀ 1.05–1.07 (M: 1.06); msrw/arw: 1.40–1.48; msrw/minrw: 1.40–1.48; msrw/eyl: 1.20–1.33; brl/eyl: ♂ 0.57–0.67 (M: 0.61), ♀ 0.61– 0.73 (M: 0.67); eyl/hl: 0.64–0.71; frw/mtrw: ♂ 0.71–0.78 (M: 0.75), ♀ 0.67–0.70 (M: 0.69); hl/hw: ♂ 0.73–0.74 (M: 0.73), ♀ 0.74–0.78 (M: 0.76); mpw/hw: ♂ 1.14–1.23 (M: 1.19), ♀ 1.27–1.29 (M: 1.28); bpw/apw: 1.05–1.16; pl/mpw: 1.10–1.18; mew/mpw: 1.79–1.88; el/pl: 2.57–2.78; el/mew: 1.67–1.71; mew/bew: 1.18–1.23; bew/ mpw: ♂ 1.49–1.59 (M: 1.53), ♀ 1.46–1.49 (M: 1.48); pft/msrw: ♂ 0.75–0.83 (M: 0.80), ♀ 0.85–0.90 (M: 0.88); ptbl/pl: ♂ 0.87–0.98 (M: 0.92), ♀ 0.86–0.87 (M: 0.87); ptbl/ptbmw: 4.88–5.52.

Rostrum weakly sexually dimorphic, very short and stout, much shorter than pronotum; mesorostrum with small tooth-like expansion above antennal pits; prorostrum narrowing apicad from antennal insertion; punctuation and clothing of appressed and semi-erect short piliform scales dorsally dense along basal two-thirds of rostrum, major distal dorsal part of prorostrum bare, shiny and finely punctate ( Figs. 189–192 ), on sides entire prorostrum asetose and coarsely punctate; basal part of rostrum on sides densely microreticulate, with antennal pits surrounded by broad and deep hollowings occupying major part of rostrum base in profile ( Fig. 197 ); venter of rostrum confusedly punctate, on prorostrum punctures without setae; between antennal pits with a high transverse hump bearing protruding setae; scrobes shallow, not meeting between eyes, with well-defined outer edges vanishing on head, broadly separated by flat, punctured and setose septum ( Fig. 201 ).

Mouthparts with maxillary palpifer having complete, curved, sharp ventral edge ( Fig. 202 ); lacinial part densely setose, with 4 stout falcate setae; labium with long and narrow setose ligula; the paired premental setae in deep pits; labial palps with long single sub-basal seta.

Head distinctly transverse, with large semi-globular eyes having ommatidia more flattened and larger than in most other apionines; epifrons between eyes distinctly narrower than rostrum base, flat, with dense setiferous punctures and usually with median pit or fovea; vertex even with epifrons and densely punctate over distance less than one-fifth eye length, then glabrous; temples only shortly microsculptured behind eyes, with just single row of punctures along eye margin, some punctures bearing long erect setae; subocular fringe absent, at most a few short protruding setae present; gular sector relatively short, weakly convex, coarsely punctate and setose ( Fig. 201 ).

Antennae moderately long; insertion ♂ ♀: 0.32–0.41; scape and funicle with weakly protruding setation; club segments all with dense recumbent pilosity, lacking longer, protruding setae; scape subequal in length or only slightly longer than fun1 + 2; length/width ratio: scape 2.0–2.5, fun1 1.7–2.0, fun2 2.0–2.2, fun6 1.1–1.3, fun7 1.0–1.1, club 3.9–4.2; length of scape/fun1 1.6–2.0, fun1/fun2 1.0–1.2, fun3 0.9–1.0 × as long as fun1, fun4 to fun7 of about the same length, barely elongate to isodiametric; club as long or longer than combined length of 5 distal funicular segments, subcylindrical for most of its length, not distinctly pseudotetramerous, interspaces between segments narrow, basal segment isodiametric, median segment transverse ( Fig. 203 ).

Pronotum elongate, shaped as in Figs. 188 & 200 , with dense, obliquely directed piliform scales on sides; disc weakly convex, lacking transverse wrinkles in front, with punctures of variable size and density, usually not much larger than single ommatidium and less than one ommatidium diameter apart, interspaces of punctures microreticulate, slightly uneven; prescutellar fovea varying in length and extent of impression, at most 0.25 × as long as pronotum; sub-basal line variably extended, discernible only near pronotal corners; notosternal suture ending in small pit very close to anterior prothoracic margin; postcoxal side without impression or lateral fovea; prosternum bare, declining; posterior rim of procoxae only lateral, obliterated in middle; prosternellum narrow, subconical, separated from hypomeron by superficial Y-shaped depression; hypomeron flat, about twice as long as prosternum, with complete transverse row of setiferous punctures ( Fig. 201 ).

Scutellar shield weakly elongate, prominent, with median furrow.

Elytra oval, widest in middle, with prominent humeri, basally joining with a multituberculate lock ( Fig. 206 ), gently convex ( Fig. 198 ), in dorsal outline with well separated caudal part; interval 3 at base with aggregation of small punctures and tuft of semi-recumbent light piliform scales; striae weakly impressed, without sharp edges, 2–3 × narrower than intervals, catenulate-punctate, with row of short piliform scales touching each other; intervals nearly flat at base, becoming convex since one-third of elytron, microreticulate and with dual punctuation, larger punctures ordered, hosting long erect setae, on the declining apical part of elytra all settled on small asperities; minute punctures irregularly disposed; sutural interval completely flat and depressed as long as it covers basal sutural lock, becoming transversely raised towards suture at beginning of sutural shelf/slot; apex of interval 5 elevated to form a low tubercle; specialized setae indistinguishable.

Wing as in Fig. 199 , similar as in Rhynchitapion ; radial window narrow; cubito-anal vein remnants distinct, paired, straight; main anal vein (2A) straight or slightly angled in middle, simple; subsequent 3A vein barely discernible; anal notch deep and narrow.

Mesoventrite largely impunctate in middle, with several setiferous punctures on sides and base of intercoxal process; mesepimeral sulcus well impressed, sharply edged on mesoventrite side, widening upwards, with setiferous punctures; anapleural sutures indiscernible; mesepimera impunctate, bare. In septum of mesocoxae, mesoventral process several times longer than metaventral one ( Fig. 204 ). Metaventrite barely longer than mesocoxal cavities, flattened in middle, coarsely punctate and setose except for small median area, on projection between metacoxae with deep, elongate median pit; intermesocoxal process short, raised ( Fig. 204 ). Abdominal ventrites as in Figs. 213 & 214 ; punctures varying in size, smaller and sparser on ventrites 1–2, specifically in their middle, coarser on basal part of ventrite 5 and on sides of ventrites 3–4; ventrite 5 twice as broad as long (2.00–2.25 ×) and gently convex on both sexes, with apical margin broadly rounded laterally and nearly straight in middle.

Legs short and robust. Procoxae sparsely covered with semi-recumbent setae, in inflated basal part strongly scale-like microsculptured, in contrast to polished narrowed apices. Femora markedly inflated; entire profemur both coarsely punctured and irregularly transversely wrinkled, 2.6–2.7 × as long as high. Tibiae all widening apicad, subcylindrical, with enlarged dense apical tuft of long yellowish setae, specifically on meso- and metatibiae ( Fig. 196 ); protibia along inner side with unordered semi-recumbent setae; tibial apex with ring of dense, yellowish thin setae, lacking pair of distinct setae ( Fig. 195 ). Tarsi short, with weakly elongate two basal tarsomeres; tarsomere 1 subtruncate, tarsomere 2 shallowly emarginate ( Fig. 212 ); protarsus 2.5–2.8 × as long as wide; length/width ratio of tarsomeres: 1st—1.2–1.6, 2nd—1.0–1.2, 3rd 0.6–0.7; onychium protruding beyond 3rd tarsomere by half its length, without projecting special setae; adhesive sole distinct, composed of relatively long and fine yellowish setae; claws with broad, lamelliform teeth ( Fig. 208 ).

Male. Mucro on mesotibia spine-like ( Fig. 210 ), on metatibia falciform or truncate ( Fig. 211 ). Pygidium transversely rectangular, short, lacking any marginal ridge, but densely punctate-setose in apical one-fourth of length ( Figs. 215, 216 ). Sternite VIII broadly divided into narrow, crescentic hemisternites ( Fig. 222 ). Spiculum gastrale Y-shaped, short, slightly asymmetrical, with apodeme about 1.6 × as long as the basally expanded fork. Tegmen as in Figs. 220 & 221 , subarticulated; basal piece short and broad, with rounded arms; apodeme 2.5–2.7 × longer than basal piece, in lateral view attached at distinct angle; tegminal plate short, 1.1–1.2 × as long as wide, broadest at connection with basal piece, not produced latero-ventrally; parameral lobes short, broadly rounded, divergent; suprafenestral sclerites narrowly crescentic, lacking membranous extensions, bearing 4–5 very short macrochaetae at most as long as sclerite; fenestrae large, well delimited by sclerotized margins, shortly oval, in middle fully separated by narrow median sclerotization, laterally with narrow openings about one-third of fenestra length; postfenestral plate undivided, expanded laterally; prostegium short, weakly surpassing tegminal articulation, with lateral stripes of sclerotization much narrower than transparent middle. Penis short, 2.2–2.3 × as long as wide ( Fig. 218 ), in side view as in Fig. 219 ; apodemes 1.2–1.3 × as long as pedon, dichotomous basally, broadly connected with tectum, subarticulated with pedon; tectum evenly sclerotized, two-thirds as long as pedon; pedon swollen at base, with lateral margins sinuate in dorsal outline, apically narrowed, radiately canaliculate; endophallus small, weakly projecting between penile apodemes in repose, entirely densely microspinose, without any sclerites besides bar-like frena, receiving broad ejaculatory duct in about mid-length of exposed part.

Female. Tergite VII almost entire, evenly sclerotized, densely punctate and setose ( Fig. 225 ). Tergite VIII narrowly divided into hemitergites. Spiculum ventrale straight, ca. 2.5 × as long as gonocoxite, with strongly transverse, microsetose and weakly sclerotized sternal plate ( Fig. 224 ). Coxites strongly divergent in repose, small, ovoid, narrowed and truncate basally, about twice as long as wide; styli stout, twice as long as wide, sub-perpendicular to coxite, shortly setose apically ( Fig. 226 ). Bursa short and broad, its membrane densely microspinose in distal third ( Fig. 223 ). Spermatheca c-shaped, thin, with small corpus and long cornu ( Figs. 227, 228 ).

Biology. The host plant in South Africa is Apodytes dimidiata E. Mey. ex Arn. (Metteniusaceae) , larval development probably in generative parts.

Distribution. Northern Tanzania (Ukerewe Is. on Victoria Lake), Eastern R.S.A. (KwaZulu-Natal, Eastern Cape, Western Cape).

The type species of this monotypic genus is actually represented by two probably allopatric subspecies recorded from different parts of South Africa .

Figures

FIGURES 187–199. Lepanomus crinalis zuluensis ssp. n. Male: dorsal habitus (187); pronotum in dorso-lateral view (188). Male head and rostrum in dorsal view, L. c. zuluensis ssp. n. (189), L. c. crinalis Balf.-Br. (190). Female head and rostrum in dorsal view, L. c. zuluensis ssp. n. (191), L. c. crinalis Balf.-Br. (192). Elytral intervals in anterodorsal view, L. c. zuluensis ssp. n. (193), L. c. crinalis Balf.-Br. (194). L. c. zuluensis ssp. n. Male protibia and tarsal sole (195). Female metatibia (196). Male rostrum and head, lateral view (197). Female: lateral habitus (198); wing (199).

FIGURES 200–211. Lepanomus crinalis zuluensis ssp. n., SEM micrographs. Male: rostrum, head and prothorax, dorsal view (200); same, ventral view (201); mouthparts (202); antenna (203); mesoventrite, mesocoxae and metaventrite (204); left elytron, lateral view (205); left elytron inside, sutural slot and postscutellar lock (206); apex of right elytron, inner side (207); tarsal claws (208); unarmed protibial apex (209); mesotibial mucro (210); metatibial mucro (211).

FIGURES 212–228. Lepanomus crinalis zuluensis ssp. n. Male protarsus (212). L. c. crinalis Balf.-Br., abdominal ventrites, male (213), female (214). L. c. zuluensis ssp. n. Male: pygidium in posterior (215), dorsal (216) and lateral (217) views; penis in dorsal (218) and lateral (219) views; tegmen in dorsal (220) and lateral (221) views; sternite VIII inside pygidium (anterior view) and sternite IX (222). Female: bursa, ventral view (223); tergite VIII and spiculum ventrale (224); tergite VII (225); gonocoxites (226). Spermathecae: L. c. zuluensis ssp. n. (227), L. c. crinalis Balf.-Br. (228).