Moiradiomus nanita, Vandenberg & Hanson, 2019

Vandenberg, Natalia J. & Hanson, Paul E., 2019, Overview of the lady beetle tribe Diomini (Coleoptera: Coccinellidae) and description of a new phytophagous, silk-spinning genus from Costa Rica that induces food bodies on leaves of Piper (Piperaceae), Zootaxa 4554 (1), pp. 255-285 : 277-278

Moiradiomus nanita sp. nov.

( Figs. 19, 20 , 28 , 32 , 41 )

Diagnosis. This species is readily distinguished from its congeners by the male genitalia ( Fig. 32 ) with its short, broad paramere (length only 2× width), basal lobe in ventral view strongly tapered toward apex with rounded apical knob, and penis tube with slight angulation and irregular swelling near distal ½. In addition, the adult form ( Figs. 19, 20 ) is smaller and relatively shorter than in the other species, and the prosternal carinae ( Fig. 28 ) are nearly parallel, framing a subtrapezoidal depression. It is also distinguished by its larval host plant: P. reticulatum L., 1753.

Description of holotype (male) ( Fig. 19 ). Length 1.3 mm, width 0.9 mm. Form shortened, oval weakly convex. Metathoracic wing present. Dorsal surfaces feebly shining, distinctly punctate, pubescent with fimbriate borders. Head, pronotum, appendages including mouthparts, straw yellow, with meso- metacoxae slightly darkened; base of pronotum in front of scutellar shield with light brown smudge; scutellar shield light brown; elytron light brown with apex narrowly yellow brown, epipleuron yellow brown, nearly transparent; pubescence shiny, off white. Venter predominantly light brown; prosternum pale yellow; mesepimeron, mesepisternum paler than surrounding sclerites except posterior margin of mesepimeron narrowly darkened; abdomen light brown, lighter, yellower toward apex; tarsal claw, mandibular apex dark reddish amber. Dorsal punctation moderately coarse; punctures separated by approximately 1× diameter, on elytron equal in width to eye facet, finer on head, pronotum. Dorsal pubescence semi erect, moderately dense, evenly distributed, lacking distinct setal pattern; individual setae equal to about 2/3 to 1× length of scutellar shield, arcuate; elytral setae mostly directed posteriorly except directed outwardly at sides of body, posterolaterally near suture. Head large, 0.80× width of pronotum; eye large, finely facetted, with interfacetal setae, weakly notched near antennal insertion by small rounded ocular canthus; inner orbits arcuate, strongly diverging toward vertex, weakly diverging toward clypeus, with minimum separation at slightly below midlength; interocular distance 1.2× width of eye in frontal view. Antenna composed of 10 antennomeres; antennomere 3 elongate, about 1.8× length of antennomere 4; last 4 antennomeres forming gradual club expanding apically from antennomere 7–9; antennomere 10 subrhomboidal, slightly narrower, slightly longer than 9. Maxillary palp with terminal palpomere short, strongly expanded distally; with oblique apex. Pronotum transverse, width 2.0× length, weakly, evenly convex. Elytron in dorsal view with lateral margin weakly arcuate; elytral apices dehiscent. Ventral surfaces pubescent, distinctly punctate, except glabrous, impunctate in posterior 4/5ths of metacoxal plate; punctation coarser, denser on abdomen. Prosternum ( Fig. 28 ) with carinae of intercoxal process extending to apex, subparallel, framing subtrapezoidal depression. Suture between abdominal ventrites 1 and 2 distinct, linear; 5 th ventrite with apex truncate; 6 th ventrite with apex shallowly, roundly emarginate in median ½. Tarsal claw with broad scythe-like inner tooth extending from base to apical 1/3rd or beyond.

Male genitalia ( Fig. 32 ). Basal lobe in ventral view ( Fig. 32b ) strongly, unevenly tapered toward apex, with small knob at distal most point, slightly shorter than paramere; in lateral view ( Fig. 32a ) nearly flat in basal 2/3rds sinuous in apical third with upturned apex; paramere short and broad, strongly expanded toward obliquely rounded apex, about 3.0× as long as wide, slightly longer than longest setae. Penis ( Fig. 32c ) lacking apical flagellum, slender with irregular swelling at apical ½; capsule wedge shaped.

Female ( Fig. 20 ). Similar to male except pronotum light brown; prosternum, mesepimeron, mesepisternum medium brown. 5 th abdominal ventrite with posterior margin truncate; 6 th ventrite with posterior margin arcuate. Tarsal claw with short triangular tooth near base, not extending beyond apical ½.

Variation. Length 1.1–1.5 mm. Individuals vary slightly in the extent and degree of dark pigmentation on dorsal and ventral surfaces.

Trophic relations. Larvae develop on food bodies of P. reticulatum ( Fig. 41 ).

Etymology. Nanita, proper noun in apposition, from Nan (a version of Ann) + ita (diminutive). A reference to an old nursery rhyme or cantrip used to encourage a coccinellid to fly from your fingertip: Ladybird, ladybird, fly away home. Your house is on fire. Your children all roam, except little Nan, who sits in a pan, weaving gold laces as fast as she can.

Type material. Holotype (male) with labels: “ COSTA RICA: Heredia: OTS-La Selva , 100m II.2013, P. Hanson / ex. Piper reticulatum ” ( USNM) ; 9 paratypes (4 males, 5 females): 8 with same labels as holotype; 1 with labels: “ COSTA RICA: Puntarenas: Rincon de la Osa, I.2017, P. Hanson / ex. Piper reticulatum ” (5, USNM; 4, MZUCR).

Figures

FIGURES 17–20. Moiradiomus species habitus illustrations. 17, M. atropos: holotype, male; 18, M. atropos: paratype, female. 19, M. nanita: holotype, male; 20, M. nanita: paratype, female. Scale bar = 0.5 mm.

FIGURES 25–28. Diagrammatic ventral view of Moiradiomus prosterna (setae, color patterns, and surface punctation not indicated): 25, M. clotho; 26, M. lachesis; 27, M. atopos; 28, M. nanita.

FIGURES 29–32. Male genitalia of Moiradiomus species (a, left lateral view of phallobase; b, ventral view of phallobase; c, left lateral view of penis; d, apex of basal lobe, enlarged): 29, M. clotho; 30, M. lachesis; 31, M. atopos; 32, M. nanita.

FIGURES 40–42. Tents of Moiradiomus spp.: 40, M. lachesis on Piper lanosibracteum; 41, M. nanita on P. reticulatum; 42, M. atropos on P. friedrichsthalii.