Moiradiomus, 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 : 278

Key to species of Moiradiomus

The species of Moiradiomus can be readily separated by characteristics of the male genitalia and the species of larval host plant. Additional morphological and color differences are added to the key as confidence characters, but we project that these will prove insufficient for identification purposes, particularly considering our small sample sizes and the potentially large number of undescribed species in the genus.

1. Male genitalia with short, broad paramere (length only 2× width) ( Fig. 32a ); basal lobe in ventral view ( Fig. 32b ) strongly tapered toward apex with rounded apical knob. Penis tube ( Fig. 32c ) with slight angulation and irregular swelling near distal ½. Larvae develop on food bodies of P. reticulatum . Adults proportionally shorter ( Figs. 19, 20 ) than other known species, with prosternal carinae ( Fig. 28 ) nearly parallel, framing subtrapezoidal depression......................... M. nanita , n. sp.

1’. Male genitalia with paramere longer (length approximately 2.5–3.0× width) ( Figs. 29a, 30a, 31a ); basal lobe not as above. Penis tube without angulation and swelling near distal ½ ( Figs. 29c, 30c, 31c ). Larvae develop on other Piper hosts. Adult form elongate oval ( Figs. 13–18 ), prosternal carinae more or less distinctly converging toward apex, framing subtriangular to ovoid depression ( Figs. 25–27 )........................................................................... 2

2. Male genitalia with basal lobe strongly unevenly tapered in apical half ( Fig. 29b ), terminating in hook-shaped process resembling a vulture’s head ( Fig. 29d ). Larvae develop on food bodies of Piper holdridgeianum . Adult with terminal maxillary palpomere elongate, moderately expanded distally ( Figs. 13, 14 )....................................... M. clotho , n. sp.

2.’ Male genitalia with basal lobe nearly parallel-sided in apical half, terminating in oblique apex ( Figs. 30b, 31b ). Larvae develop on other Piper hosts. Adult with terminal maxillary palpomere short, strongly expanded distally ( Figs. 15–18 )............ 3

3. Basal lobe of male genitalia with pronounced dorsal hump at basal 1/3, forming a conspicuous subangulation in lateral view ( Fig. 31a ). Prosternum with strongly convergent carinae framing subtriangular depression with attenuate, narrowly rounded apex ( Fig. 27 ). Larvae develop on food bodies of Piper friedrichsthalii . Adult form narrow, tapered toward apex; male with scutellar shield same color as elytron, and base of pronotum in front of shield with light brown transverse mark ( Fig. 17 )........................................................................................... M. atropos , n. sp.

3’. Basal lobe of male genitalia with dorsal surface nearly flat, weakly sinuous in lateral view ( Fig. 30a ). Prosternum with weakly convergent carinae framing elongate ovoid depression ( Fig. 26 ). Larvae develop on food bodies of Piper lanosibracteum . Adult form less narrow, oval with lateral margins nearly parallel-sided, then rounded off in apical 2/5; male scutellar shield may be paler than elytron and base of pronotum in front of shield without brown transverse mark ( Fig. 15 )...................................................................................................... M. lachesis ., n. sp.

Figures

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 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 13–16. Moiradiomus species habitus illustrations. 13, M. clotho: holotype, male; 14, M. clotho: paratype, female. 15, M. lachesis: holotype, male; 16, M. lachesis: paratype, female. Scale bar = 0.5 mm.