Mesomphalia Hope, 1839

Simões, Marianna V. P. & Monné, Marcela L., 2014, Taxonomic Revision of the genus Mesomphalia Hope, 1839 (Insecta, Coleoptera, Chrysomelidae), Zootaxa 3835 (2), pp. 151-197 : 153-155

Mesomphalia Hope, 1839

Mesomphalia Hope, 1839: 94 ; Chapuis, 1875: 394; Boheman, 1850: 112, 1856: 37; Chapuis 1875: 394; Wagener, 1881: 62; Spaeth, 1914: 32; Jolivet & Hawkeswood, 1995: 163; Borowiec, 1999: 117; Borowiec & Świętojańska2014. Stolas subgenus Mesomphalia: Hincks, 1952: 334 ; Seeno & Wilcox, 1982: 174; Chaboo, 2007: 237.

Type species. Cassida gibbosa Fabricius, 1781 (by original designation).

Diagnosis. Mesomphalia is distinguished from other Mesomphaliini genera by the following combination of features: integument black and sculptured, 11 cylindrical antennomeres, with four basal subglabrous; short and curved mandibles; maxillary palpomere I long, twice as long as III; mentum short; labium membranous; prosternum Rounded with elongated and longitudinally grooved process; anterior third of elytra with shared acute conical gibbosity; prosternal collar with anterior margin curved, lateral extremities projected and divergent, followed medially by transverse sulcus; elytra, in lateral view, with abrupt anterior slope and gradual posterior slope.

Description. Body almost circular (except M. sublaevis , with length 1.3x width) in dorsal view; head partially concealed; pronotum and elytra slightly contiguous. In lateral view, body with gibbosity at the basal third of the elytra. Pronotal and elytral lateral margins explanate.

Dorsal integument black and sculptured, abdominal ventrites smooth surfaced. Head ( Figs. 1–3 ) matt with erect, long and dense setae. Eyes ( Figs. 1–3 ) oval, 1.5x wider than long, finely faceted and laterally prominent. Vertex with erect, long and sparse setae, coarse and dense punctures. Frontal tubercles ( Fig. 3 ) well-defined, slightly protuberant, and directed posteriorly. Coronal suture ( Fig. 1 ) deep, with smooth depression at apex. Frontoclypeus ( Fig. 3 ) protuberant anteriorly, with dense setae and coarse punctation; epistomal suture discernible. Mandibles short and curved; maxillary palpomere I long, twice as long as III; mentum short; labium membranous; prosternum rounded with elongated and longitudinally grooved process. Antennae ( Figs. 11 , 91–93 ) filiform, slightly flattened dorso-ventrally, wider at apex, with 11 cylindrical antennomeres, reaching anterior margin of elytra when reflexed. Scape, pedicel, and antennomeres III–IV with long and sparse setae; V–XI with short and dense setae on the sides and sparse setae at apex of antennomeres. Scape globose, 2.5–3.0x longer than pedicel; XI wider at post-median region, narrowing to truncate apex, 1.5– 2 x length of X.

Prothorax ( Figs. 12–15 , 94–96 ) matt and transverse. Pronotum ( Figs. 12 , 94–96 ) about twice as long as wide; anterior margin slightly concave, exposing head; longitudinal median line ( Figs. 94–95 ) smooth and glabrous, not reaching the margins; disc elevated; posterior angle ( Figs. 96 ) slightly projecting posteriorly. Prosternal collar ( Figs. 13–14 , 98 ) with anterior margin curved, lateral extremities projecting and divergent; median region with transverse sulcus. Prosternal process ( Fig. 13 ) narrowed medially with longitudinal sulcus; apical region expanded. Scutellum (Fig. 23) triangular and smooth.

Mesoventrite ( Figs. 16, 18 ) transverse. Mesoventral process depressed, with protuberant lateral margins. Elytra macroreticulate (Figs. 21–22) with basal margin faintly crenulate; lateral margins slightly or markedly oblique on males and rounded on females; apical 2/3 of margin flattened and explanate; apical posterior angle slightly projected; anterior third with shared acute conical gibbosity; in lateral view, with abrupt anterior slope and gradual posterior slope. Humeral angle rounded, smooth and glabrous (except M. tumidula ), slightly projected anteriorly. Disc with conical gibbosity at the basal third, height about twice the greatest elytral width; in lateral view, with abrupt anterior slope and gradual slope posteriorly. Metaventrite ( Figs. 16, 18 ) with anterior margin excavated, adjacent to metacoxae.

Legs ( Figs. 25–39 ) subequal in length and clothed in decumbent, long and sparse setae, except tibia, with setae becoming denser towards apex. Pro- and mesocoxae globose; metacoxae transverse; trochanters triangular; femora fusiform with basal third smooth, dilated, and apical 2/3 microreticulate and depressed; tibia slightly expanded to apex, with apicodorsal surface notched to receive tarsus. Tarsomeres ( Figs. 28–29, 33–34, 38–39 ) II–III bilobed; tarsomere I half the length of II; II as long III, but more robust; IV absent; V slightly longer than III. Tarsal claws ( Fig. 40 ) reddish-brown, curved, tapered and appendiculate.

Abdomen completely covered by elytra. Ventrites shiny, except ventrite I with microreticulation on basal third to two-thirds; ( Figs. 41–43 , 48–49 ) I–IV subequal in length; V with erect, long setae, becoming denser towards median region and covering apical third, with flat posterior margin on males and preapical median depression on females.

Remarks. Hope (1839) described Mesomphalia in detail. Spaeth (1901) revised Mesomphalia and redefined it with the following attributes: prosternum with anterior margin projected anteriorly, with divergent anterolateral angles, followed by a transverse sulcus; elytra with gibbosity at basal third and an acuminate apex. In addition, all species of Mesomphalia have: black integument without metallic iridescence; deep coronal suture; basal antennomeres subglabrous, with long and sparse setae; pronotum and elytra with setae, always forming macules on the pronotum.

Within the tribe Mesomphaliini , Mesomphalia resembles Cyrtonota Chevrolat, 1836 , Trilaccodea Spaeth, 1902 and Stolas . Cyrtonota and Mesomphalia share the following: subglabrous basal antennomeres, pronotum transverse with subparallel lateral margins, elytra with basal margin crenulate, disc convex, tarsal claws apendiculate and divaricate. Cyrtonota is distinguished by: integument may be irridescent metallic; antennomere V subglabrous; pronotum varying from nearly impunctate to coarsely punctate; prosternal collar not projecting, and without transverse sulcus.

Mesomphalia and Trilaccodea share: pronotum transversely pentagonal, with impunctate, dull, base on each side with distinct impression; surface of pronotum with setae on the surface; prosternal collar elongate, often angulate on sides. However, they differ greatly in other aspects. Trilaccodea has: integument with color patterns or metallic; elytra extremely broad, base around twice width base of pronotum; disc with large, blunt postscutellar tubercle; profile behind the tubercle sinuous or slightly concave with apical angle of elytra pointed downwards (Borowiec 2007). Mesomphalia always has: integument strictly black, not metallic; elytra not wider than pronotum base; disc with sharply conical postscutellar gibbosity; profile behind the gibbosity slightly straight, with apical angle of elytra pointed upwards.

The similarity between Stolas and Mesomphalia is strong and led previous authors to synonymise them ( Hincks 1952; Seeno & Wilcox 1982; Chaboo 2007), but without clear justification. Stolas and Mesomphalia share the following features: basal antennomeres subglabrous; pronotum in some species with subtriangular macules of yellowish-brown setae; elytra with basal margin faintly crenulate and disc with gibbosity at basal third. However, in Stolas the integument may be metallic, the parascutellar disc may have macules of yellowish-brown setae (e.g. Stolas brevicuspis (Spaeth, 1922)) , the prosternal collar is never projecting and the prosternal transverse sulcus is absent.

Outside Mesomphaliini , the most similar genus is Goniochenia Weise, 1896 . It belongs to the tribe Goniocheniini Spaeth, 1942, which is characterized by the toothed claw and claw segment, while Mesomphaliini has untoothed claws ( Hincks 1952). Apart from variation in this tribal character,, Goniochenia (s. str.) and Mesomphalia share integument without metallic iridescence, basal antennomeres subglabrous, and pronotum transverse, width at least 2x length.

Little biological information is available for Mesomphalia . Haitlinger (1991) reported an association of a canestriniid mite Arrunsithiana battisi with M. gibbosa ( Fabricius, 1781), 1781 , and 14 species of Stolas . Jolivet & Hawkeswood (1995) recorded Ipomea L. ( Convolvulaceae ) as the host plant of Mesomphalia , but without citing a reference for this. The only confirmed host plant species is Mikania glomerata Spreng. (Asteraceae) , which is attributed to M. gibbosa ( Flinte et al. 2008) .

Figures

FIGURES 1 – 10. Mesomphalia gibbosa (Fabricius, 1781) (male). 1 – 3, head: 1, dorsal view; 2, lateral view; 3, ventral view; 4 – 7, mandibles: 4, dorsal view; 5, ventral view; 6, superior lateral view; 7, inferior lateral view; 8, labrum, dorsal view; 9, labium, ventral view; 10, maxillae, dorsal view. Scale = 1 mm.

FIGURES 11 – 15. Mesomphalia gibbosa (Fabricius, 1781) (male). 11, antenna, dorsal view; 12 – 15, prothorax: 12, dorsal view; 13, ventral view; 14, lateral view; 15, frontal view (pr, proendosternite; ps, prosternal sulcus). Scale = 1 mm.

FIGURES 91 – 97. Mesomphalia gibbosa (Fabricius, 1781). 91 – 93, antenna: 91, general aspect, arrows showing longitudinal grooves; 92, antennomere VI, with long and erect setae at the apex, and longitudinal suture next to the apex; 93, antennomere XI, with longitudinal suture at the median region; 94 – 97, pronotum: 94 – 95, median line smooth; 96 – 97, projection of posterior margin.

FIGURES 98 – 100. Mesomphalia variolaris Boheman, 1850. 98, ventral view; 99, dorsal view; 100, lateral view (pc, prosternal collar; ed, elytral disc; gb, gibbosity; lm, lateral margin; ts, transversal sulcus).

FIGURES 16 – 20. Mesomphalia gibbosa (Fabricius, 1781) (male). 16, meso – and metaventrites; 17, meso – and metendosternite; 18, meso – and metathorax; 19 – 20, metendosternite: 19, dorsal view; 20, ventral view (a, arm, la, lamina; me, mesendosternite; te, tendon). Scale = 1 mm.

FIGURES 25 – 40. Mesomphalia gibbosa (Fabricius, 1781) (male). 25, procoxa; 26, profemur; 27, protibia; 28 – 29, protarsomere: 28, dorsal view; 29, lateral view; 30, mesocoxa; 31, mesofemur; 32, mesotibia; 33 – 34, mesotarsomere: 33, dorsal view; 34, lateral view; 35, metacoxa; 36, metafemur; 37, metatibia; 38 – 39, metatarsomere: 38, dorsal view; 39, lateral view; 40, apendiculate claws. Scale = 1 mm.

FIGURES 41 – 47. Mesomphalia gibbosa (Fabricius, 1781) (male). 41, abdomen, ventral view; 42, ventrite V, general aspect; 43, tergite VIII, dorsal view; 44 – 45, median lobe; 44, lateral view; 45, dorsal view of the apex; 46 – 47, tegmen: 46, dorsal view; 47, lateral view. (ed, ejaculatory duct; ma, manubrium; o, ostium; te, tegmen). Scale = 1 mm

FIGURES 48 – 54. Mesomphalia gibbosa (Fabricius, 1781) (female). 48, abdomen, ventral view; 49, sternite VII, general aspect; 50, sternite VIII; 51, sternite IX; 52, tergite X; 53, sternite IX and tergite X, lateral view; 54, spermatheca (am, ampulla; ed, spermatheca duct; Gl, ductus glandula auxiliaris; va, vasculum). Scale = 1 mm.