Meibomeus cyanipennis (Sharp, 1885)

Ribeiro-Costa, Cibele S. & da Silva, José Aldir Pinto, 2003, Morphology of Adult Meibomeus cyanipennis (Sharp) (Coleoptera: Bruchidae), The Coleopterists Bulletin 57 (3), pp. 297-309 : 298-308

Meibomeus cyanipennis (Sharp, 1885)

( Figs. 1–47 )

Head elongate, oblique. Frons (f) medially with a smooth frontal carina (c) which extends from the clypeus to the vertex, differentiating itself from the rest of the integument, which is punctured ( Figs. 4 , 42, 43 ). Clypeus (cl) subpentagonal with subparallel lateral margins and integument slightly scale-like in appearance and provided with sparse setae ( Fig. 42 ). Epistomal suture conspicuous (eps) as inverted ‘‘V’’ ( Figs. 4 , 42 ). Postoccipital sulcus and postoccipital suture not evident. Occiput (ocp) ( Fig. 7 ) conspicuously rounded. Gula (gu) ( Fig. 5 ) pentagonal and weakly demarcated, except next to the posterior foramen. Gular suture (gs) short, slightly curved. Eye (e) moderately protuberant laterally, interocular ratio about 0.16. Ommatidia, about 17, with short setae between them ( Fig. 44 ). Ocular sinus deep (os) ( Figs. 4, 7 ). Eye supercilium (es) with foveolae larger than those on the frons ( Figs. 4 , 43 ), postocular lobe slender (pl) ( Fig. 7 ). Antennal articles from fifth to tenth, serrated; last article subelliptical ( Figs. 8, 9 ). In males, articles serrated from the fifth to the tenth, slightly longer than wide when compared to those of the female, which are quadrangular ( Fig. 9 ). Gena (g) between the base of the mandible and the inferior lobe of the eye, with a length of about 0.7 times the shortest distance between the superior lobes of the eyes ( Figs. 4, 5, 7 ). Labrum ( Fig. 4 ), rectangular, sides rounded, subtruncate apex; integument with a scale-like appearance at the base and smooth at the apex ( Fig. 42 ), internal side of the labrum with sparse, long setae in the lateral third and two rows of very short setae in the median region ( Fig. 10 ). Torma (tr) with elongate arms more dilated at the apex, membranous area between the arms with setae forming an inverted ‘‘Y’’. Between the bifurcation of the ‘‘Y’’ is the epipharynx, with dense hairs. Mandible ( Fig. 11 ), symmetrical, subtriangular, with slightly curved apex and sparse setae at the base of the external margin. Prostheca (pr) membranous; mola (ml) with small rugosities. Maxilla ( Fig. 12 ) with cardo (cd) slender and elongate; stipe divided into basal stipe (bs) and medial stipe (ms). Fourth segment of the maxillary palp (mp) as long as the the others together. Galea (ga) with simple and pectinate setae having an annulate sclerite at the basal region (beg). Lacinia (lc) shorter than galea, with simple and dense setae. Labium with the submentum (sm) continuous between the genae ( Fig. 5 ). Mentum (m) with two lateral lobes, the epilobes (epl), which are broad and conical. Palpiger inconspicuous, palpifer longer than wide. Ligula (li) with numerous marginal setae. Internally ( Fig. 14 ), in the median region of the pre-mentum, with two rows of short setae. Tentorium with anterior and posterior tentorial arms ( Fig. 6 ), the posterior ones united by the transverse tentorial bridge (bt).

Pronotum ( Figs. 1 , 15 ) campanulate, truncate at the apical margin, sinuous at the base and with foveolae, except at the basal half of the medial line ( Fig. 45 ). Pronotal disk raised (pd), basal lobe slightly emarginate (bl) ( Figs. 15 , 45 ) and without lateral carinae. Submarginal sulcus (sbs) present at the basal margin of the pronotum, except in the region of basal lobe ( Fig. 45 ); cervical sulcus (cs) evident, largely encircling the anterior foramen (afo) ( Fig. 17 ); cervical boss (cb) with two setae ( Figs. 16, 17 , 44 ). Hypomeron (hp) fused to the pronotum ( Fig. 3 ). Anterior coxal cavities (cc) elliptical; trochantin absent; prosternum (ps) with sharp apex not separating completely the coxal cavities ( Figs. 16, 17 ). Proendosternite (ped) ( Fig. 18 ) with two slender arms dilated at the apex. Short scutum (sc), anterior margin arched; scutellum (sct) quadrangular with posterior edge slightly emarginate ( Fig. 2 ).

Elytron with a length about two times that of its largest width, all striae with moderately thick punctures followed by slender sulci ( Fig. 46 ). Basal region with the fourth stria shorter than the third and the fifth, starting with a small elevation or tooth (to) ( Figs. 1, 3 , 46 ). Mesepimeron ( Fig. 3 ) reduced to a small triangular sclerite above the mesepisternum, separated from this by the mesopleural suture (mes). Mesepisternum (msp) more developed, reaching the coxal cavity ( Figs. 3 , 21 ). Truncate mesosternum (ms) between the middle coxae. Mesendosternite (med) ( Fig. 19 ) with slender arms slightly convergent and inclined dorsally toward the sides; with two small processes turned inward near the divergent area ( Fig. 19 ).

The scutum (scu) is the largest part of the metanotum ( Fig. 20 ), with two rounded areas slightly convex; between these areas an elongate medial depression with prominent parallel margins; anteriorly bounded by the acrotergite which is contiguous with the prephragma (pre), this bent inward and with a bilobed anterior margin; scutellum represented externally by the medial depression and internally by strong apodemes that diverge toward the apex; postnotum (pn) contiguous with the postphragma, medially bilobed, with two lateral projections slightly arched and angular. Metepimeron covered by the elytra while the metepisternum is wide and lacks sulci or sutures ( Fig. 3 ). Metasternum (mts) ( Fig. 21 ) bordered anteriorly by the postcoxal sclerite (pcs) which surrounds part of the medial coxal cavities, and posteriorally by the antecoxal sclerite (acs). Metendosternite in the shape of a ‘‘Y’’, arms divergent (ar) with apex in lateral view subtriangular; tendons long (t) ( Fig. 22 ). Axillary region of the hind wing ( Fig. 27 ) constituted by three axillary sclerites (1Ax, 2Ax and 3Ax) and two contiguous middle plates (proximal, Mp and distal, Mp 9). Besides the axillary area, hind wings show the remigial regions (Rr), vannal (Vr) and jugal (Jr) regions and two fold-lines, the anterior (Af) and the posterior (Pf). Costa (C) is a short and moderately sclerotized vein, situated at the anterior basal part of the costal margin (MC) and its base is associated with the humeral plate (Hp). Subcosta (Sc) associated at the base with the 1 8 axillary sclerite (1Ax), longer than the costa (C), contacting this in a small area. Radial vein (R) associated with the 2 8 axillary sclerite (2Ax), about one-third the length of the wing, forming distally the pterostigma (Pt). This consists of a small radial cell (Rc) formed by veins R1 and r. In the third apical of the wing there is an isolated branch formed by the fusion of R 2 þ 3 veins. Radial sector (RS) submembranous, extending subparallel to R. Media vein (M) associated in the axillary region with the R vein and distal median plate (Mp 9); it is extended obliquely up to about the middle of the length of the wing. Branches M, M 3 þ 4, m-m, M 1 þ 2 form an open cell. From this, the subbranch M3, is directed to the external margin of the wing while M1 is an oblique branch, isolated, in the distal part of the wing. The r-m and M 1 þ 2 are placed in the medial part of the wing. The vannal region is composed of M3 and by the fusion of the cubitus and post-cubitus veins. The cubitus (Cu 1b) and post-cubitus (Pcu) form the cubitus cell, (2Cu,) near the base of the wing. Basal part of the Cu 1b associated with the 3 8 axillary sclerite (3Ax). Jugal region with distinct short vein, the jugal vein (1J).

Anterior coxa (cx1) ( Fig. 24 ), elongate, subcylindrical, gradually connate at the apex; trochanter subtriangular (tr1); femur (fe1) a little shorter than the tibia; first tarsal segment with a length similar to the second. Middle coxa (cx2) rounded ( Fig. 25 ), less prominent than anterior one; femur (fe2) and tibia (ti2) almost equal in length; first tarsal segment about twice the length of the second. Hind leg with coxa (cx3) ( Figs. 3 , 21, 26 ) conspicuously different than the others, length similar to the largest width of the hind femur and being inserted almost totally in the coxal cavity, being visible only the external face which shows foveolae evenly distributed for the most part, except in the anterior cavity where the femur (fe3) is encased. This slightly narrower at the base than at the apex, with external lateral margin (elm), sinuous and lacking carinae ( Fig. 26 ); internal lateral margin (ilm) ( Fig. 23 ) without teeth or with two denticles (tee) anterior to the pecten (pe), which is constituted by an elongate tooth followed by a row of five to six denticles ( Figs. 23, 26 , 47 ). First denticle, if present, at about less than half the femur length, and the second at the middle of its length. Hind tibia ( Fig. 26 ), at the lateral margin, with two carinae, lateroventral (lvc) and lateral (lc), subparallel and of the same length; the lateroventral terminating in the direction of the mucro and the lateral in the direction of one of the coronal denticles. Ventral carina (vc) straight in 3 = 4 apical, slightly curved near the base; external carina (ec) slightly rough ( Fig. 23 ). Internal face ( Fig. 23 ) with long dorsomesal carina (dm), not reaching the apex of the tibia and distant from the external carina (ec) at about 1/4 of the largest width of the tibia. First posterior tarsal article approximately 2.5 times the length of the second.

Seven visible urotergites, with five pairs of spiracles in the pleurites of the abdominal segments ( Fig. 28 ). Pygidium (py) with curved lateral margins and rounded apex ( Fig. 31 ). Length of the first urosternite in the medial region, slightly larger than the rest of the sterna. From the second to the fifth urosternite with a similar size, emarginate in males ( Fig. 29 ) whereas in the females with a straight apical margin ( Fig. 30 ).

Male terminalia. Eighth urotergite, almost membranous, rounded apex with a few short setae ( Fig. 33 ); eighth urosternite with the shape of a ‘‘T’’, basal region membranous and apical region sclerotized termed the spiculum gastrale (gsp) ( Fig. 32 ). Median lobe ( Fig. 35 ) as a conspicuously elongate tube, sclerotized for the most part and with vestige of a fracture near the apical region. Dorsal valve (dv) and ventral valve (vv) triangular, with convex lateral margins and groups of small setae at the base. Middle lobe with a rounded basal region, slightly concave, called the cucullus (cs). Internal sac (is) attached in the base of the valves, near the apical orifice of the middle lobe and has sparse denticles. Tegmen ( Fig. 34 ) extremely elongate, narrow, with parallel lateral margins and rounded lateral lobes, with short setae and separated by a slight emargination.

Female terminalia. Eighth urotergite ( Fig. 39 ), reduced, with the apex more sclerotized than the base and with few long setae. Eighth urosternite ( Fig. 40 ) has a rectangular appearance, anterior margin slightly rounded and with short and long setae; spiculum gastrale (gsp) slightly curved from the side view ( Fig. 41 ). The ovipositor ( Fig. 38 ), the ninth abdominal segment, is enveloped by the eighth tergum and sternum, consisting of two coxites (cxt) with a slight medial depression, some long setae at the apex and two slender styli (st). Bursa (bu) ( Fig. 41 ) membranous and without sclerites. Spermatheca (s) in the form of a broadened capsule with strongly curved projection; duct short and united to the apical region of the bursa.

General Considerations

Meibomeus cyanipennis is externally similar to M. sulinus Silva and Ribeiro-Costa. In M. cyanipennis the male internal sac has separated denticles whereas in M. sulinus these groups together form two rows.

The occipital sulcus of M. cyanipennis is not as evident as in Pachymerinae (Nilsson and Johnson 1993). This sulcus corresponds to the occipital suture, which according to Singh (1982), is absent in Bruchidae . The postoccipital suture is absent in M. cyanipennis and in Caryedon gonagra (Mathur and Dadhial 1963) . However, Singh (1982) reported the presence of such a suture in genera that he studied.

The medial process at the tentorial bridge described by Singh (1981 b) in Callosobruchus chinensis was not observed in M. cyanipennis .

In the illustrations of the maxilla of Caryedon gonagra (F.) (Mathur and Dadhial 1963:269; Singh 1986:56) there is a differentiated annulate area at the base of the galea. In M. cyanipennis the presence of a sclerite was observed surrounding the base of the galea, which had simple and unipectinate setae, similar to those of Specularius bridwelli Arora ( Singh 1986) .

The palpigers of M. cyanipennis are not differentiated from the prementum as in Caryedon gonagra (F.) (Mathur and Dadhial 1963:269) and Callosobruchus chinensis ( Singh, 1981 b) .

The number of setae on the cervical boss varies in Bruchidae . In M. cyanipennis there are two setae. These number is characteristc of specialized bruchids (Kingsolver, pers. comm.).

The costal vein in M. cyanipennis does not show a break as in Caryedon lineatonota Arora , nor is it very curved as in Sulcobruchus kingsolveri Arora (Singh 1981) . In Bruchus , Conicobruchus , Caryedon , Spermophagus , Sulcobruchus and Zabrotes , the branch M1 is very elongate, connecting to r-m ( Singh 1981 a). In M. cyanipennis , M1 is isolated and localized in the distal part of the wing, with no connection to r-m.

The shape of the metendosternite of M. cyanipennis resembles more that of Rhaebus gebleri Fischer (Rhaebinae Chapuis) ( Crowson 1955). Daviault (1928:112) illustrated the metendosternite of Acanthoscelides obtectus (Bruchinae) and Crowson (1944: fig. 85) the metendosternite of Caryoborus rubidus (Chev.) [¼ Caryobruchus rubidus (Chev.) ] (Pachymerinae). In both species, the metendosternite differs in relation to M. cyanipennis . In the case of A. obtectus , principally by the shape of the apex of the arms, and in the case of C. rubidus by the wide divergence of these.

In M. cyanipennis no sclerites were found in the bursa. Nevertheless, in some species of Amblycerus Thunberg (Ribeiro-Costa, pers. comm.) and Pachymerinae (Nilsson and Johnson 1993) sclerites are present in different shapes and sizes.

Figures

Figs. 1–9. Meibomeus cyanipennis (Sharp). 1) dorsal view; 2) scutum and scutellum; 3) lateral view; 4) head, anterior view; 5) head, posterior view; 6) idem; 7) head, lateral view; 8) male antenna; 9) female antenna. a ¼ tentorial arm, af ¼ antennal fossa, atp ¼ anterior tentorial pit, bt ¼ tentorial bridge, c ¼ frontal carina, cl ¼ clypeus, cls ¼ clypeolabral suture, cx2 ¼ middle coxa, cx3 ¼ hind coxa, e ¼ eye, eps ¼ epistomal suture, es ¼ eye supercilium, f ¼ frons, fe3 ¼ hind femur, g ¼ gena, gs ¼ gular suture, gu ¼ gula, hp ¼ hypomeron, la ¼ labrum, li ¼ ligula, m ¼ mentum, ma ¼ mandible, mes ¼ mesopleural suture, mf ¼ maxillary fossa, mp ¼ maxillary palp, msp ¼ mesepisternum, mtp ¼ metapleural suture, mte ¼ metepisternum, mts ¼ metasternum, ocp ¼ occiput, os ¼ ocular sinus, p ¼ pedicel, pl ¼ postocular lobe, pm ¼ prementum, pof ¼ posterior foramen, ptp ¼ posterior tentorial pit, s ¼ scape, sc ¼ scutum, sct ¼ scutellum, sm ¼ submentum, too ¼ tooth, ve ¼ vertex.

Figs. 10–18. Meibomeus cyannipenis (Sharp). 10) ventral view of the labrum; 11) inner face of the left mandible; 12) left maxilla; 13) labium, outer view; 14) labium, inner view; 15) pronotum, dorsal view; 16) pronotum, ventral view; 17) pronotum, anterior view; 18) pronotum, posterior view: afo ¼ anterior foramen, beg ¼ basal sclerite of the galea, bl ¼ basal lobe, bs ¼ basal stipe, cb ¼ cervical boss, cc ¼ anterior coxal cavity, cd ¼ cardo, con ¼ condyle, cs ¼ cervical sulcus, epl ¼ epilobe, ga ¼ galea, las ¼ labial suture, lc ¼ lacinia, li ¼ ligula, lp ¼ labial palp, ls ¼ labral suture, m ¼ mentum, mes ¼ suture of the mentum, ml ¼ mola, mp ¼ maxillary palp, ms¼ mesostipe, pd ¼ pronotal disk, ped ¼ proendosternite, pf ¼ palpifer, pm ¼ prementum, pr ¼ prostheca, ps ¼ prosternum, sbs ¼ submarginal sulcus, tr ¼ torma.

Figs. 19–26. Meibomeus cyanipennis (Sharp). 19) inner view of the mesosternum; 20) metanotum; 21) ventral view of the thorax; 22) metendosternite; 23) inner view of the hind leg except for the coxa and tarsals; 24) fore leg; 25) middle leg; 26) hind leg. acs ¼ antecoxal sclerite, ar ¼ arms, ca ¼ wing condyle, cx1 ¼ anterior coxa, cx2 ¼ middle coxa, cx3 ¼ hind coxa, dm ¼ dorsomesal carina, ec ¼ external carina, elm ¼ external lateral margin, fe1 ¼ anterior femur, fe2 ¼ middle femur, fe3 ¼ hind femur, ilm ¼ inner lateral margin, lc ¼ lateral carina, lvc ¼ lateroventral carina, med ¼ mesendosternite, mep ¼ mesepimeron, mes ¼ mesopleural suture, ms ¼ mesosternum, msp ¼ mesepisternum, mte ¼ metepisternum, mts ¼ metasternum, mu ¼ mucro, pe ¼ pecten, pn ¼ postnotum, pre ¼ prephragma, scl ¼ scutellum, scu ¼ scutum, pcs ¼ postcoxal sclerite, st ¼ stalk, t ¼ tendons, ta ¼ acetabulum of the trochanter, ti1 ¼ anterior tibia, ti2 ¼ middle tibia, ti3 ¼ hind tibia, tee ¼ teeth, tr1 ¼ anterior trochanter, tr2 ¼ middle trochanter, tr3 ¼ hind trochanter, ts ¼ tarsals, vc ¼ ventral carina.

Figs. 27–33. Meibomeus cyannipenis (Sharp). 27) Right hind wing; 28) dorsal view of the abdomen; 29) male abdomen; 30) female abdomen; 31) pygidium; 32) eighth sternum; 33) eighth tergum. Af ¼ anterior fold, AR ¼ axillary region, 1Ax ¼ first axillary sclerite, 2Ax ¼ second axillary sclerite, 3Ax ¼ third axillary sclerite, C ¼ costa, Cu1b ¼ cubitus, 2Cu ¼ cubitus cell, gsp ¼ spiculum gastrale, Jr ¼ jugal region, 1J ¼ jugal vein, Hp ¼ humeral plate, M ¼ middle vein, M1 ¼ middle branch1, M1 þ 2 ¼ middle 1 þ 2, M3 þ 4 ¼ middle 3 þ 4, M3 ¼ middle 3, m-m ¼ transverse middle, ME ¼ externalmargin, MC ¼ costal margin, MPo ¼ posterior margin, Mp ¼ proximal middle plate, Mp9 ¼ distal middle plate, PCu ¼ Post-cubitus, Pf ¼ posterior fold, Pt ¼ pterostigma, py ¼ pygidium, R ¼ radial, r ¼ radial transverse vein, Rr ¼ remigial region, R1 ¼ radial 1, R2 þ 3 ¼ radial 2 þ 3, Rc ¼ radial cell, r-m ¼ radial-middle transverse vein, Rs ¼ radial sector, Sc ¼ subcosta, sp ¼ spiracle, stI ¼ first urosternite, tgI ¼ first urotergite, Va ¼ vannal region.

Figs. 34–37. Meibomeus cyannipenis (Sharp). Male terminalia. 34) tegmen, ventral view; 35) medial lobe, ventral view; 36) tegmen, lateral view; 37) medial lobe, lateral view. cs ¼ cucullus, bp ¼ basal piece, ed ¼ ejaculatory duct, is ¼ internal sac, ll ¼ lateral lobes, ts ¼ tegminal strut, vd ¼ dorsal valve, vv ¼ ventral valve.

Figs. 38–41. Meibomeus cyanipennis (Sharp). Female terminalia. 38) ovipositor; 39) eighth tergum; 40) eighth sternum; 41) female terminalia, lateral view. cxt ¼ coxite, gsp ¼ spiculum gastrale, bu ¼ bursa, s ¼ spermatheca, st ¼ stylus.

Figs. 42–47. Meibomeus cyannipenis (Sharp). 42) anterior view of the head (1433); 43) frons and part of the eyes (2743); 44) eyes from lateral view (3413); 45) dorsal view of the pronotum (1863); 46) dorsal view of part of the elytrum with setae indicating the presence of a tooth at the base of the fourth stria (1703); 47) pecten (5033).