Merma ankarana, Szawaryn & Czerwiński, 2023

Szawaryn, Karol & Czerwiński, Tomasz, 2023, Three new species of Merma Weise (Coleoptera: Coccinellidae: Epilachnini) from Madagascar, Zootaxa 5306 (2), pp. 266-276 : 267-270

Merma ankarana sp. nov.

Figs 1A–C , 2

urn:lsid:zoobank.org:act:FDDD4E80-8E44-45E6-AAE8-41AA169DBDDD

Diagnosis. Coloration of M. ankarana is identical to all other Malagasy species of the genus Merma . From M. hovana and M. quadriguttata it can be easily separated by its larger body size, tarsal claws with additional subquadrate basal tooth and emarginate apex of ventrite 5 in male (males of M. hovana and M. quadriguttata have arcuate apex). General body outline and less explanate lateral elytral margin M. ankarana sp. nov. shares with M. fisheri sp. nov., while M. antakotako has slightly more explanate elytral margin. Merma ankarana also has the largest elytral spots, however, it is based only on a single holotype specimen. With M. antakotako it shares emarginate ventrite 5 in male, while in M. fisheri it is rounded. The most reliable character to separate that species are structures of the male genitalia: penis guide in lateral view with inner margin distinctly sinusoidal in middle; penis with narrow lateral thorn-like projection, and a single row of small thorns.

Etymology. The specific epithet is given after the Réserve spéciale d’Ankarana, where the holotype was collected.

Description. Length 5.5 mm, width 4.8 mm; length/width ratio = 1.14. Body ( Fig. 1A–C ) roundly oval, strongly convex, dorsum pubescent. Head, mouthparts, legs and abdomen reddish-orange. Pronotum chestnut brown with anterior corners and lateral margins orange. Elytra chestnut brown, with two orange or reddish maculae on each elytron, the first placed below humeral callus, the second in apical part of elytron.

Head transverse, partially concealed in prothorax. Interocular distance about 0.6 times of head width. Inner eye orbits slightly emarginate antero-medially, closest in the middle. Antenna composed of 11 antennomeres, about as long as 0.6 head width; scape large, elongate, slightly swollen; pedicel distinctly narrower than scape, elongate; antennomere 3 elongate, 1.3 times longer than pedicel; antennomeres 4–7 elongate, about 1.5 times as long as its width; antennomere 8 as long as wide; antennomeres 9–11 forming a distinct asymmetrical club. Ventral antennal grooves distinct in anterior part, moderately long and straight, along inner margin of eye. Clypeus short, parallel-sided, its anterior margin emarginate, smooth without groove. Labrum transverse, short, anterior margin emarginate, membranous.

Prothorax. Hypomeron smooth, simply / finely punctate. Prosternal process smooth, without carinae, bordered laterally. Prosternum in front of coxa about as long as coxal longitudinal diameter; anterior margin, uniformly arcuate, bordered; posterior margin with bordering line starting from the base of prosternal process, laterally reaching notosternal suture. Surface of prosternum covered with sparse small punctae.

Pterothorax.Mesoventral process covered with small tubercles along lateral margins, about as wide as mesocoxal diameter; meso-metaventral suture straight. Elytra with puncte of two sizes; lateral margins distinctly explanate, entirely visible from above. Epipleuron complete, broad, with distinct depressions to accommodate mid and hind legs in repose, inner margin with broad bordering line present in median and apical part. Mesoventrite covered with sparse and small punctures, with just a few larger in median part. Metaventral postcoxal lines joined on metaventral process forming straight line, recurved and then descending laterally.

Legs short and stout with apices of mid and hind femora not protruding from outer margin of elytral epipleuron. Trochanters elongate, angulately produced, with bordering line on their outer surfaces, and cavities on their inner surfaces for receiving tip of tibiae in repose. Protibiae slightly widened, all tibiae on outer edge with oblique carina near apex, without distinct apical spurs. Tarsal claws double with additional subquadrate basal tooth, empodium absent.

Abdomen with five ventrites with ventrite 5 emarginate posteriorly ( Fig. 2A ). Abdominal postcoxal lines descending, sub-parallel to posterior margin of ventrite 1, recurved shortly laterally. Apical margin of tergite VIII rounded ( Fig. 2B ) and sternite VIII straight ( Fig. 2C ); apodeme of sternum IX ( Fig. 2E ) rod-like.Tergite X transverse, truncate apically ( Fig. 2E ).

Male genitalia ( Fig. 2D, F–I ). Tegminal basal piece with a pair of indistinct spines on inner margin near base of tegminal strut. Penis guide symmetrical in inner view ( Fig. 2F ), as long as parameres, distal ¼ of its length strongly tapering into apex; in lateral view ( Fig. 2D ) outer edge straight with strongly curved tip and with densely setose field in the median part, inner edge strongly sinusoidal in median part. Parameres well developed, rounded apically. Tegminal strut distinctly shorter than penis guide, stout, strongly expanded distally. Penis rod-like, sinuate ( Fig. 2G ); penis tip ( Fig. 2H ) asymmetrical, with narrow thorn-like projection; apex in inner view ( Fig. 2I ) with narrow thorn-like projection on one side and with row of denticles on the other side; penis capsule with arms weakly developed.

Distribution. Madagascar ( Fig. 6 ).

Type material. Holotype: male, “ Madagascar, Ankarana , 25 X 45, Vadon ”( MNHN).

Figures

FIGURE 1. Habitus of Merma species. A–C) M. ankarana sp. nov., male, holotype (MNHN); A) dorsal; B) lateral; C) frontal; D–F) M. antakotako sp. nov., male, paratype (MNHN); D) dorsal; E) lateral; F) frontal; G–I) M. fisheri sp. nov., male, holotype (CAS); G) dorsal; H) lateral; I) frontal.

FIGURE 2. Merma ankarana sp. nov., male, holotype (MNHN): A) abdomen; B) tergite VIII; C) sternite VIII; D) tegmen, lateral; E) abdominal segments IX and X; F) tegmen, inner; G) penis, lateral; H) penis tip, lateral; I) penis tip, inner.

FIGURE 6. Distribution map of Merma.