Acanthosomatidae, Signoret, 1863

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 : 40-41

Key to the Acanthosomatidae of Madagascar and the Seychelles

1. Mesosternal carina not developed. Antennae 5-segmented, antennomere 2 not exceptionally long. Metathoracic scent gland complex as in Fig. 33 ; mesopleura with lateral round black spot. Broadly oval bugs of pentatomid appearance. Noualhieridia Breddin, 1898 ........................................................................................................ 2

– Mesosternal carina well developed. Antennae 4-segmented, antennomere 2 very long. Metathoracic scent gland complex different ( Figs. 31-32 ), mesopleura without lateral round black spot. Slender species, body more or less parallel. ......................................................................................................................................................... 4

2. Body dorsally (including connexiva), antennae and legs entirely terracotta orange to red. Antero-lateral margins of pronotum convex. ...................................................................................... Noualhieridia rufa Cachan, 1952

– Body dorsally, antennae and legs multicoloured. Antero-lateral margins of pronotum convex or concave with pale spot; base of corium with another pale spot laterally; postero-lateral angles of connexiva with black spots. ............................................................................................................................................................................. 3

3. Antero-lateral pronotal margins convex, with oval pale spot overlapping to pronotal disc; trochanters, apices of femora and entire tibiae, tarsi and antennae black. ............................... Noualhieridia ornatula Breddin, 1898

– Antero-lateral pronotal margins slightly concave, with long narrow pale spot not overlapping to pronotal disc; legs and antennae entirely pale, only apical halves of antennomeres 3-5 blackened. .......................................... ............................................................................................................ Noualhieridia marginata Cachan, 1952

4. 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. ........... Catadipson Breddin, 1903 : Catadipson imernensis ( Cachan, 1952)

– Not conspicuously elongate, parallel species. Head only as broad as ca one half to one third of pronotal width). Mandibular plates without apical spines, meeting or not in front of clypeus. Humeral angles of pronotum each with conspicuous spine. Metathoracic scent gland complex as in Fig. 31 . Connexival margins spinous. Head and pronotum with small dark punctures. Mahea Distant, 1908 ...................................................................... 5

5. Humeral angles gradually narrowed, each produced into conical spine, not constricted basally. ...................... 6

– Humeral angles abruptly narrowed, constricted, each with long needle-like spine. ........................................... 8

6. Smaller species (7.3 mm). Humeral angles of pronotum less prominent ( Figs. 28-29 ). Head slightly narrower than half of pronotal width. Clypeus narrowly free apically. Lateral connexival spines as in Fig. 30 . ................ ....................................................................................................................................... Mahea parvula sp. nov.

– Larger species (> 8 mm). Humeral angles of pronotum more prominent ( Figs. 8-9 , 12-13 ). Head as wide as about one third of pronotal width. Clypeus completely enclosed apically. Lateral connexival spines different ( Fig. 10 ). .............................................................................................................................................................. 7

7. Body almost uniformly yellowish ochraceous with small dark punctures (except darkened lateral corners of pronotum, apex of scutellum, antennae and paired black spots laterally on abdominal venter). Head with vague impressed rows of punctures. Apex of scutellum more broadly rounded. Sternum without black punctures. Hairs on antennomere 2 shorter than its diameter. Metapleura not swollen. Lateral connexival spines as in Fig. 10 .. ........................................................................................................................... Mahea andriai ( Cachan, 1952)

– Body more colourful, covered with prominent black punctures. Basic colour ochraceous, posterior part of pronotum with reddish tones. Anterior part of scutellum reddish brown, antero-lateral angles and posterior part contrastly pale, apex of scutellum black. Dark punctures on head, pleura and abdominal venter coalescent, forming conspicuous rows (usually impressed and darkened). Apex of scutellum narrowly rounded. Sternum with black punctures. Hairs on antennomere 2 as long as or slightly longer than its diameter. Metapleura conspicuously swollen. Lateral connexival spines as in Fig. 16 . ........................................................... Mahea distanti sp. nov.

8. Larger, more robust species (7.5-8 mm). Humeral angles not raised upwards ( Figs. 2-3 ). Male: metapleura swollen; hind femora and tibiae curved inwards; abdomen ventrally with only one row of black spots mediolaterally on sterna 3-7; connexiva as in Fig. 4 ; postero-lateral angles of sternum 7 triangular, not curved laterad ( Fig. 4 ). Female: connexiva as in Fig. 5 . ............................................................. Mahea sexualis Distant, 1908

– Smaller, more slender species (5.9-6 mm). Humeral angles raised askew upwards ( Figs. 20-21 ). Male: metapleura not swollen; hind femora and tibiae not curved inwards ( Fig. 22 ); abdomen ventrally with three rows of black spots on each side of sterna 3-6; connexiva as in Fig. 23 ; postero-lateral angles of sternum 7 broadly lanceolate, distinctly curved laterad ( Fig. 23 ). Female: unknown. ................................ Mahea durrelli sp. nov.

Figures

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.

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

Figs. 8-10. Mahea andriai (Cachan, 1952). 8 – pronotum, dorsal view; 9 – pronotum, posterior view; 10 – abdomen, 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. 17-19. Mahea distanti sp. nov. 17 – pygophore, ventral view; 18 – right paramere, dorsal view; 19 – aedeagus (basal articulatory apparatus omitted). Scale bars 0.5 mm.

Figs. 20-23. Mahea durrelli sp. nov. 20 – pronotum, dorsal view; 21 – pronotum, posterior view; 22 – hind leg (claws missing); 23 – abdomen, ventral view.

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