Meibomeus rodneyi Romero and Johnson

Romero, Jesús & Johnson, Clarence Dan, 2002, Five New Species Of Meibomeus Bridwell From The New World With Host Records For Them And Six Named Species (Coleoptera: Bruchidae), The Coleopterists Bulletin 56 (2), pp. 182-202 : 196-199

Meibomeus rodneyi Romero and Johnson , new species

Male. Length (pronotum­elytra) 1.8–2.0 mm. Width 1.1–l. 2 mm. Maximum thoracic depth 0.9–1.0 mm.

Integument Color. Integument black, not metallic; antennal segments, front legs, 0.66 of mesofemur, mesotibia, mesotarsus, and 0.66 of metatarsus and tip yellowish; eyes dark red to shiny black.

Vestiture. Sparse, pronotum with mixed golden and whitish hairs, with more dense golden hairs surrounding dense patch of white hairs on median basal lobe; scutellum white; elytra with sparse mixed golden and white hairs; dense white hairs on small apical portion of mesepisternum and ocular sinus; pygidium with sparse, short white and golden hairs, but with dense basal band of white somewhat longer hairs.

Structure. Head. Frons with fine medial longitudinal carina; eyes about twice as long as width of frons, not sexually dimorphic, in some specimens facets coarse, about 2 to 3 rows of facets behind ocular sinus; interocular ratio about 0.28–0.40; antenna extended to about 0.90–0.98 length of elytron, pedicel about 0.75 of scape length and about 0.83– 0.95 as long as segment 3, segment 11 slightly more elongate than 10, acuminate at apex.

Prothorax. Disk subcampanulate with many punctations in no apparent pattern; cervical sulcus deep, extending from near coxal cavity to 0.5 distance to pronotal midline; lateral prothoracic carina vague, extending from base to about 0.3 distance to coxal cavity; prosternum separating procoxae for about 0.7 their length; short median basal line on median basal lobe often obscured by dense white hairs; a deep, broad, gentle, diagonal sulcus on either side of midline near base.

Mesothorax and Metathorax. Scutellum quadrate, bifurcate at apex; elytron without distinct basal gibbosity; stria 4 only slightly abbreviated basally, not ended by strong tooth; striae 3 and 5 slightly less abbreviated; other striae subequal at base; elytron about twice as long as broad; striae deep, punctate; strial intervals punctulate; metasternum deep, rounded in profile; metasternum separated medially at apex by vague, short sulcus, with 2 strong spines projecting ventrally on either side of sulcus near apex; hind femur constricted basally and apically, expanded medially to slightly more than width of coxa ( Fig. 13); inner ventral surface with vague longitudinal carina; lateral margin of femur in a long gentle curve to apex; lateral margin with several minute spines from near base to a single large spine about 0.55 from base, spine about 0.8 as long as width of tibial base; inner margin with 4 subapical acuminate spines beginning about 0.3 from apex; each spine about 0.5 as long as width of tibial base; tibia with ventral, lateroventral, lateral and dorsomesal glabrous carinae; dorsal surface of tibia rugulose, without fossa; tibial corona with one vague lateral spinule, mucro small, about 0.1 as long as first tarsomere; tarsomere 1 with ventral, lateral and mesal longitudinal carinae.

Abdomen. First abdominal sternum with polished lateral apical band; sterna 2–4 unmodified, fifth sternum elongate, 2.5 as long as fourth, gently curved at apex, not emarginate, apex produced ventrally. Pygidium with many fine punctations, narrow, apex narrow, curved ventrad.

Genitalia. Median lobe thin, elongate, constricted on lateral margins; ventral valve sclerotized, apex bent ventrally, with one large seta on either side of midline and 3 small setae near lateral margins; dorsal valve less sclerotized, rounded apically; only apical 0.5 of internal sac with armature, most of apical 0.25 lined with fine scales and remaining 0.25 lined with small spinules ( Fig. 14 ). Lateral lobes elongate, cleft to 0.2 their length, apex of lobes more strongly sclerotized, with strong setae at apex of lobes ( Fig. 15 ).

Female. Length (pronotum­elytra) 1.7–2.0 mm. Width 1.0–l. 3 mm. Maximum thoracic depth 0.85–1.0 mm.

Similar to male except interocular ratio about 0.38–0.44, antenna with segments 6–10 dark brown varying to yellowish with vague brown spots, some specimens with segment 5 and 11 partially brown; metasternum without medial, vague, short sulcus, with 2 poorly developed spines projecting ventrally on either side near apex; fifth abdominal sternum small, 1.7–2.0 as long as fourth.

Host Plants. Desmodium glabrum (Mill.) DC. : México: Oaxaca: 2 km N Puerto Angel , I­4­80, C.D. Johnson collector ( CDJ #1337­80 ).

Type Series. Holotype male, allotype female and paratypes: México: Oaxaca: 2 km N Puerto Angel , I­4­80, reared seeds no. 1337­80, C.D. Johnson collector . Holotype and allotype deposited in the U.S. National Museum of Natural History , Washington, D.C., U.S.A. Paratypes deposited in the CDJ, JRN, AT, CIB and FDA collections.

Distribution. México (Oaxaca).

Discussion. Meibomeus rodneyi , M. campbelli , M. wenzeli Kingsolver and Whitehead , and M. juarez are the only species of Bruchidae that we know in which males (or females) have two strong spines at the base or apex of the metasternum. Meibomeus rodneyi , M. campbelli and M. wenzeli have apical metasternal spines and M. juarez has basal metasternal spines. Meibomeus juarez has very distinct male genitalia that do not resemble the other three species discussed here. The genitalia of M. rodneyi , M. wenzeli , and M. campbelli separate the three species. Meibomeus rodneyi has an elongate, thin median lobe with few spinules in the internal sac and more deeply cleft lateral lobes ( Figs. 14, 15 ) that separate it from M. wenzeli . The very complex apex of the median lobe of M. campbelli separates it from the other two. M. wenzeli , M. campbelli and M. rodneyi share the character ‘‘hind femur with a large tooth on the lateral margin of the hind femur separated from pecten on the apex of the medial margin by a wide gap and apical metasternal spines.’’ These structures hint that these three species may form a species group within Meibomeus . Meibomeus juarez has basal metasternal spines but does not have a large, lateral spine on the hind femur. Perhaps spines on the metasternum show affinities with the above three species but we only consider these spines as perhaps independently evolved.

Etymology. This species is named in honor of Rodney Dirl Johnson, son of the second author, for his contributions in gathering data on bruchids in the field.

Figures

Figs. 14–15. Meibomeus rodneyi male genitalia. 14) Median lobe; 15) lateral lobes.