Afidentula Kapur

Tomaszewska, Wioletta & Szawaryn, Karol, 2013, Revision of the Asian species of Afidentula Kapur, 1958 (Coleoptera: Coccinellidae: Epilachnini), Zootaxa 3608 (1) : -

Afidentula Kapur

Afidentula Kapur, 1958: 324 . Type species, by original designation: Epilachna manderstjernae Mulsant, 1853 .

Diagnosis and comment. Within Epilachnini , the species of Afidentula are most similar to those of Afidenta and Afissula in having bifid tarsal claws provided with basal tooth, and abdominal sternite VIII in female not divided longitudinally. Afidentula can be separated from these genera by an absence of tibial spurs and by small, compact and short mandibles provided with three apical teeth, of which only the middle tooth is sometimes weakly serrated.

Mandibles of Afidenta and Afissula are much longer and thinner; in Afidenta the teeth and inner surfaces bear complicated serrations, and in Afissula , mandibles have two apical teeth and one acute, subapical tooth. Moreover, species of Afissula have antennae distinctly longer than head width, with all antennomeres much longer than wide, hind femora not swollen and ovipositor with coxites of typical ‘coccinellid’ type, subtriangular and elongate.

From other Euro-asian and African genera of Epilachnini , Afidentula can be easily separated by combination of comparatively small body size, tarsal claw with basal tooth and undivided sternite VIII in females.

The well sclerotized, small and compact mandibles with short, non-serrated teeth in Afidentula is probably an adaptation to feeding on hard material such as tissue of grasses highly saturated with silica (in some cases it is visible that teeth surfaces are worn). Similar tendency to reduce mandible size and serration can be observed in the Palaearctic species Cynegetis impunctata (Linnaeus, 1767) and the African genus Chnootriba Chevrolat, 1837 , both of which also feed on grasses.

Redescription. Length 2.70–5.33 mm. Body round oval to elongate oval, convex; dorsum densely pubescent. Elytra light brown to reddish brown or chestnut brown, covered with black maculae, rarely also with black lateral and basal margins.

Head exposed, transverse; ventral antennal grooves rather weak, straight, along inner margin of mouthparts. Eyes finely faceted, not emarginate. Antennal insertions ( Fig. 57 ) exposed in front of eyes, close to each other, with distance between antennal sockets twice as long as distance between antennal socket and inner margin of eye. Antenna ( Fig. 59 ) shorter than width of head, 11-segmented; scape large, swollen, at least twice as long as pedicel; antennomere 3 elongate, about as long as antennomeres 4–6 together; antennomeres 4–8 usually subquadrate; antennal club relatively thick and compact, 3-segmented. Clypeus short, transverse. Labrum ( Fig. 58 ) small, transverse, covered with dense, long setae. Mandibles subtriangular in shape, narrowing towards apex, provided with three apical teeth; sometimes median tooth additionally serrate; prostheca small, densely hairy. Submentum rectangular, fused with gula with suture visible; labium ( Fig. 65 ) with mentum trapezoidal and narrowing anteriorly; prementum small, sclerotized; ligula with setose field antero-medially; labial palps 3-segmented, basal palpomere tiny, weakly transverse; second palpomere large, at least 3 times longer than first one, usually distinctly swollen; terminal palpomere shorter and usually distinctly narrower than second one, narrowing anteriorly. Gula weakly transverse, about twice as long as submentum; gular sutures deep, strongly convergent anteriorly, reaching nearly 1/3 length of gula. Maxilla ( Fig. 62 ) with cardo transverse, covered with several long hairs; basistipes entirely separated from mediastipes, covered with long setae; mediastipes glabrous; galea oval, glabrous except for long setae at apical margin; lacinia small, triangular, covered with long, dense setae; maxillary palp 4-segmented, palpomeres weakly securiform, pubescent; palpomere 3 about 0.5 times as long as palpomere 2; terminal palpomere at least slightly longer than wide.

Prothorax. Pronotum transverse, widest at base and gradually narrowing anteriorly; anterior and hind margins not bordered; anterior angles blunt, indistinct; lateral edge smooth, without submarginal carina; disc convex, finely punctate. Prothoracic hypomeron smooth; notosternal suture distinct; prosternum in front of coxa about 0.5 times as long as coxal longitudinal diameter; prosternal process about 3 times narrower than longest coxal diameter, without lateral carinae; procoxal cavity transverse with small triangular slit laterally and with bordering line anterolaterally.

Pterothorax. Mesoventrite with anterior edge with complete raised border and with more or less distinct groove behind it; mesal surface with cavity receiving prosternal process; mesoventral process at least 0.5 times as wide as coxal diameter; meso-metaventral articulation with suture visible; junction straight, without internal knob. Scutellum small, triangular. Elytra confusedly, dually punctate, at base distinctly broader than pronotum; lateral margins very narrow but usually visible from above; elytral epipleuron incomplete apically only, flat, without foveae, with submarginal carina almost complete ( Fig. 67 ); metaventrite with intercoxal process usually broadly bordered and raised with more or less distinct groove behind it, sometimes extending laterally behind postcoxal lines; metaventral postcoxal lines connected medially and complete laterally, usually straight ( Fig. 67 ); metaventrite with discrimen incomplete; metepimeron distinct. Metendosternite stalk as long as broad, tendons separated by slightly less than width of stalk and situated comparatively close to middle.

Legs rather stout; trochanters angulately produced on inner margin, with weak cavity for receiving tip of tibia ( Fig. 1 ). Pro- and mid femur cylindrical; hind femur weakly swollen ( Fig. 63 ); tibiae cylindrical, without apical spurs; tarsi pseudotrimerous; tarsal claw bifid, with large, subtriangular basal tooth ( Fig. 64 ).

Abdomen with six ventrites in males and five ventrites in females with sternite VIII partly visible. Ventrite 1 at mid line almost twice as long as ventrite 2; abdominal postcoxal lines separate medially, recurved and almost complete, deep but posteriorly separated from hind margin of ventrite; apical margin of male ventrite 5 truncate; male ventrite 6 emarginate and tergite VIII rounded; apical margin of female ventrite 5 rounded; female sternite VIII arcuate, entire and tergite VIII rounded.

Male terminalia and genitalia. Apodeme of male sternum IX rod-like. Tegmen with penis guide of various shapes in lateral view; parameres long and thin throughout, separated, articulated with phallobase, apex with several short setae; tegminal strut broad apically, somewhat triangular in shape. Penis guide with lateral sides symmetrical. Penis base with arms poorly developed; penis thin, curved, more or less in shape of a question mark.

Female genitalia. Proctiger (TX) distinct, transverse, a sclerotized plate; coxites oval, without styli, apical margin with several setae, apex sometimes with small protuberance; infundibulum absent. Bursa copulatrix usually subdivided into two parts of different sizes; larger part placed ventrally, pocket like, ending with outlet of common oviduct; smaller part placed dorsally, ending with outlet of sperm duct. Sperm duct short, simple, uniform in diameter; spermatheca small, membranous, vermiform, without clear nodulus and ramus; accessory gland long, usually adjacent to sperm duct.

Distribution. Asia: Bahrain, Bangladesh, Bhutan, China, India, Nepal, Pakistan, Sri Lanka, Thailand, and Vietnam.

Figures

FIGURES 57 – 67. Afidentula manderstjernae bielawskii spp. nov.; 57) head, antero-dorsal; 58) labrum; 59) antenna; 60) mandible, inner; 61) mandible, outer; 62) maxilla; 63) habitus, ventral view; 64) tarsal claw; 65) labium; 66) prosternal and mesoventral process; 67) metaventite and elytral epipleuron.

FIGURES 1 – 16. Afidentula bisquadripunctata (Gyllenhal); 1) habitus, ventral view; 2) head ventral view; 3) mandible, inner; 4) mouthparts; 5) prosternal and mesoventral process; 6) abdominal tergite VIII, male; 7) abdominal sternite VIII (ventrite 6), male; 8) female genitalia, ventral; 9) male genital segment, dorsal; 10) male genital segment, ventral; 11) penis, lateral; 12) tegmen, lateral; 13) tegmen, inner; 14) penis apex, lateral; 15) abdomen, female; 16) abdomen, male.