Mahea Distant, 1909

Kment, Petr, 2005, Revision of Mahea Distant, 1909, with a review of the Acanthosomatidae (Insecta: Heteroptera) of Madagascar and Seychelles, Acta Entomologica Musei Nationalis Pragae (suppl.) 45, pp. 21-50 : 23-24

Mahea Distant, 1909

Mahea Distant, 1909: 32 , pl. 4 (description, figures). Type species: Mahea sexualis Distant, 1909 , by monotypy.

Muschalea Cachan, 1952: 312 (description, figures). Type species: Muschalea andriai Cachan, 1952 , by original designation (syn. KUMAR 1974).

Mahea: KUMAR (1974) : 43 -44 (diagnosis, taxonomy).

Redescription. Body deltoid in shape; head shorter than pronotum; pronotum arched, sloping posteriad, highest between humeral angles, then descending caudad; dorsum flat; ventral side convex. Body surface slightly shining, covered with coarse dark punctures.

Head ( Fig. 1 ). Mandibular plates sinuated in front of eyes, apically curved inwards, never spinously produced; clypeus with apex narrowly exposed or completely enclosed (intraspecific variable character). Eyes large, protruding from head outline by most of its width; ocelli situated behind imaginary line through posterior margins of eyes; each ocellus nearer to eye than to each other. Antenniferous tubercles visible from above; antennae 4-segmented ( Fig. 11 ); antennomere 1 (scape) short, not or only very slightly surpassing apex of head; antennomere 2 (pedicel) very long, not subdivided, with erect pubescence; antennomeres 3 and 4 subequal in length, together about as long as antennomere 2, without erect pubescence. Bucculae low, diverging posteriad; maxillary plate tubercle developed; rostrum long, reaching or surpassing metacoxae; first rostral segment not surpassing posterior margin of eyes, hidden between bucculae.

Pronotum trapezoidal ( Fig. 28 ); anterior margin more or less slightly concave, anterolateral angles touching posterior margins of eyes; antero-lateral margins rounded, more or less diverging posteriad; humeral angles always very prominent and spinuously produced ( Fig. 2 ); posterior margin skewed posteriad to antero-lateral scutellar angles, margin anterior to scutellum concavely sinuate. Scutellum triangular, longer than clavi. Hemelytra narrow; clavi narrowly triangular (anteriorly with two rows of punctures, posteriorly with one row); corium long, triangular, acutely attenuated posteriorly and reaching middle of membrane, its posterior inner margin concave; suture between corium and membrane brown; membrane large, long oval, slightly brownish infuscated, translucent, slightly surpassing (exceptionally nearly surpassing) apices of postero-lateral angles of abdominal sternum 7 ( Fig. 14 ).

Prosternum with deep median groove, flanked by longitudinal, prominently elevated carinae. Mesosternal carina flattened laterally, extending anteriorly between procoxae and reaching posterior margin of prosternal groove, posteriorly reaching between metacoxae. Metathoracic scent gland complex inconspicuous ( Fig. 31 ); ostiole small, situated laterally between meso- and metacetabula; peritreme horizontal, slightly raised above metapleura, oval, shining; evaporatorium small, narrowly surrounding ostiole and peritreme. Metapleura swollen ( Fig. 14 ) or not. Legs pale, ochraceous, with short to very short pubescence; femora twice as long as tibiae; tarsi 2-segmented; claws slender, long, straight, apically abruptly rectangularly curved; parempodia and pulvilli developed.

Abdomen with median carina well developed on sterna 3-6 in males ( Fig. 4 ) and on sterna 3-4 in females ( Fig. 5 ), produced anteriad as abdominal spine reaching between metacoxae, resting against mesosternal carina. Connexiva (especially its posterolateral corners) with more or less prominent spines (variable between species and sexes) ( Figs. 4-5, 14, 16 ); especially postero-lateral angles of sternum 7 in males conspicuously produced; sternum 8 slightly incised posteromedially.

Male genitalia. Pygophore subquadrate ( Figs. 7, 17 , 25 ), more or less dorso-ventrally flattened ( Figs. 6, 16 , 24 ); margins of external opening setose; dorso-lateral angles slightly produced, with tuft of conspicuous setae; proctiger large, convex, exposed; hypophyses of parameres exposed from pygophore ( Figs. 7, 17 , 25 ); parameres flat, head enlarged, not bifurcate, bearing setae ( Figs. 18 , 26 ); vesica of aedeagus long, deeply sinuated ( Fig. 19 ) or looped ( Fig. 27 ).

Sexual dimorphism strongly developed. Body of females behind humeral angles less narrowed; metapleura only slightly swollen; abdomen broader, median carina short, posterior part of abdomen flat; connexival spines with more than one spine per sternum, especially on sterna 5-7; Pendergrast’s organ not developed. Hind femora and tibiae are most probably sexually dimorphic in some/all species; I cannot confirm that given the lack of material.

Differential diagnosis. According to KUMAR (1974), the presence of both abdominal spine and mesosternal carina places Mahea as a member of the subfamily Acanthosomatinae . Within the Acanthosomatinae , Mahea and Catadipson are the only genera with 4-segmented antennae. Catadipson differs from Mahea in the following characters: elongate oval species; head very broad, slightly broader than two thirds of pronotal width; apex of clypeus free; mandibular plates projected as conspicuous apical spines; humeral angles of pronotum not produced, rounded; metathoracic scent gland complex as in Fig. 32 ; connexival margins without apparent spines; head and pronotum with very large black punctures.

Distribution. This genus is known only from Madagascar (four species) and the Seychelles (Island of Mahé) (one species).

Comments. KUMAR (1974) noticed the resemblance in the descriptions of Mahea and Muschalea and considered them to be synonymous. He, however, did not examine Cachan’s type specimens of Muschalea . This synonymy is herein confirmed based on the study of type material.

Figures

Figs. 1-5. Mahea sexualis Distant, 1909. 1 – head, dorsal view; 2 – pronotum, dorsal view; 3 – pronotum, posterior view; 4 – abdomen of male (lectotype), ventral view; 5 – abdomen of female (paralectotype), ventral view.

Figs. 11-16. Mahea distanti sp. nov. 11 – antenna; 12 – pronotum, dorsal view; 13 – pronotum, posterior view; 14 – pleural margin and connexiva, dorsal view; 15 – hind leg (tarsomeres and claws missing); 16 – abdomen, ventral view.

Figs. 28-30. Mahea parvula sp. nov. 28 – pronotum, dorsal view; 29 – pronotum, posterior view; 30 – abdomen, ventral view.

Figs. 6-7. Mahea sexualis Distant, 1909. Pygophore (lectotype). 6 – posterior view; 7 – ventral view. Scale bars 0.5 mm.

Figs. 24-27. Mahea durrelli sp. nov. 24 – pygophore, posterior view; 25 – pygophore, ventral view; 26 – left paramere, ventral view; 27 – aedeagus (basal articulatory apparatus omitted). Scale bars 0.5 mm.

Figs. 31-34. Pleura and metathoracic scent gland opening, most exposed view. 31 – Mahea sexualis Distant, 1909; 32 – Catadipson imernensis (Cachan, 1952); 33 – Noualhieridia rufa Cachan, 1952; 30 – Ibocoris ficivora Roche, 1947.