Rhyzobius albinos, Czerwiński & Szawaryn & Tomaszewska, 2020

Czerwiński, Tomasz, Szawaryn, Karol & Tomaszewska, Wioletta, 2020, Three new species of the genus Rhyzobius Stephens, 1829 from New Guinea (Coleoptera: Coccinellidae: Coccidulini), European Journal of Taxonomy 692, pp. 1-17 : 2-7

Rhyzobius albinos sp. nov.

urn:lsid:zoobank.org:act:BA648A58-DE41-49CE-B3DA-F7D06F2E868C

Figs 1 A–D, 2A–I, 4A–C, 5A–D

Diagnosis

This species is most similar to R. poorani Tomaszewska, 2010 and R. jaya Tomaszewska, 2010 in body colouration. However, R. albinos sp. nov. differs from R. poorani by having simple, not swollen pronotal anterior corners and a prosternal process with complete lateral carinae, joined anteriorly in the form of a triangle. Rhyzobius jaya has a smooth prosternal process without carinae, and straight ventral antennal grooves reaching beyond the posterior margin of the eyes, whereas R. albinos sp. nov. has ventral antennal grooves distinctly circularly bent towards the outer margin of the eyes. From all other New Guinean species of Rhyzobius , R. albinos sp. nov. can be distinguished by the bright, almost white ventral body surface, excluding meso- and metaventrite.

Etymology

The specific epithet is a noun in apposition, it means ‘albino’ in Polish and refers to the bright colouration of most of the ventral surfaces, not observed in other species of Rhyzobius .

Material examined

Holotype

NEW GUINEA • ♂; Madang Province , Mt Wilhelm, Bananumbo; 5º45ʹ33.4ʺ S, 145º14ʹ08.2ʺ E; 1700 m a.s.l.; 9–11 Nov. 2012; “06686- CoCocc Ibisca Niugini 2012”; FIT-MW1700-O-8/8-d16; plot 15, order 17260; MNHN.

Paratypes

NEW GUINEA – Madang Province • 1 ♂; same collection data as for holotype; MNHN • 1 ♂; Mt Wilhelm; 2200 m a.s.l.; 18–20 Oct. 2012; “04064-CoCocc Ibisca Niugini 2012”; FIT-MW2200-C- 2/8-d03; plot 3, order 1603; MNHN • 1 ♂; Mt Wilhelm; 2200 m a.s.l.; 19–21 Oct. 2012; “09588-CoCocc Ibisca Niugini 2012”; FIT-MW2200-C-2/8-d04; plot 11, order 6111; MNHN • 1 ♂; Mt Wilhelm; 1200 m a.s.l.; 29–31 Oct. 2012; “16881-CoCocc Ibisca Niugini 2012”; FIT-MW1200-J-3/8-d05; plot 10, order 6033; MNHN • 1 ♂; Mt Wilhelm; 1700 m a.s.l.; 27–29 Oct. 2012; “P1927-CoCocc Ibisca Niugini 2012”; FIT-MW1700-G-2/8-d03; plot 7, order 18341; MNHN • 1 ♂; Mt Wilhelm; 2200 m a.s.l.; 20–22 Oct. 2012; “P2334-CoCocc Ibisca Niugini 2012”; FIT-MW 2200-I-3 /8-d05; plot 9, order 18623; MNHN • 1 ♂; Mt Wilhelm; 1700 m a.s.l.; 9–11 Nov. 2012; “06696-CoCocc Ibisca Niugini 2012”; FIT-MW1700- S-8/8-d16; plot 19, order 5202; MIZ • 1 ♂; Mt Wilhelm; 2200 m a.s.l.; 27–29 Oct. 2012; “02308-CoCocc Ibisca Niugini 2012”; FIT-MW2200-N-6/8-d12; plot 14, order 1630; MIZ • 1 ♂; Mt Wilhelm; 2200 m a.s.l.; 20–22 Nov. 2012; “P2294-CoCocc Ibisca Niugini 2012”; FIT-MW2200-D-3/8-d05; plot 4, order 18478; MIZ.

Type locality

Papua New Guinea, Madang Province, Mt Wilhelm, Bananumbo.

Description

MEASUREMENTS. Length 2.00– 2.25 mm; TL/EW = 1.42–1.50; PL/PW = 0.52–0.56; EL/EW = 1.06–1.07.

BODY ( Figs 1 A–C, 2A). Moderately oval and convex dorsally, winged; with antennae, mouthparts, hypomera, apex of elytra, most of abdominal ventrites and legs except coxae whitish; frons, anterior and lateral margins of pronotum, preapical parts of elytra, prosternum, epipleura, coxae and partially abdominal ventrite 1 pale brown; vertex, posterior and central parts of pronotum, most of elytra, meso- and metaventrite blackish or dark brown. Elytra with weak bluish, metallic sheen. Dorsum with moderately long and uniform pubescence, not forming pattern on elytra. Elytral bristles absent.

HEAD ( Fig. 1D ). Dorsally exposed with eyes almost entirely visible; ventral antennal grooves distinctly circularly bent towards outer margin of eye; corpotentorium absent. Eyes dorsally with inner orbits arcuate, closest at middle; ocular canthus distinct; interocular distance 0.50–0.52 times as wide as head across eyes; interfacetal setae distinct. Antenna ( Fig. 2B ) 0.77–0.80 times as long as head capsule width, composed of 11 antennomeres; scape 1.65–1.70 times as long as pedicel; pedicel narrower than scape, barrel-shaped, 1.25–1.28 times as long as wide; antennomere 3 about 2.5 times longer than wide, and 2.15–2.30 times as long as antennomere 4; antennomere 4 as long as 5; antennomeres 6 and 7 quadrate. Antennal club consisting of 3 antennomeres, with two subterminal segments asymmetrical; penultimate antennomere as long as terminal one; terminal antennomere rounded apically. Anterior clypeal margin ( Fig. 2E ) distinctly emarginate with rounded lateral lobes and median area membranous. Labrum truncate at apex. Maxillary cardo transverse with outer angle reaching slightly outside of mouth cavity; terminal palpomere 1.30–1.35 times as long as wide, expanded apically. Mentum weakly transverse, 1.5 times as broad as long; anterior margin weakly arcuate; ventral surface with horseshoe-like impression; prementum transverse; ligula parallel-sided; labial palps separated by distance about equal to width of palpiger; apical palpomere as long and as broad as penultimate one; submentum distinct.

PRONOTUM ( Fig. 2F ). With anterolateral angles rounded, scarcely produced anteriorly, not swollen with regular border; anterior and hind margin without border; lateral margin with entire border. Prothoracic hypomeron with weak, broad, concave area along anterior half of prothoracic lateral margin; notosternal suture weakly visible, simple; prosternal process ( Fig. 2G ) 0.55 times as broad as longest coxal diameter, its surface with lateral carinae complete, convergent and joined anteriorly forming a triangle; prosternum in front of coxa about 0.45 times as long as coxal longitudinal diameter at the same position; anterior margin continuing as weakly arcuate line, much more posterior than anterior pronotal margin; procoxal cavity distinctly transverse, without visible bordering line.

PTEROTHORAX. Anterior margin of mesoventrite with complete raised border ( Fig. 2G ); mesoventral process at median length of coxa 1.25–1.30 times as broad as corresponding coxal diameter; mesometaventrite articulation with suture visible; junction angulate posteriorly. Scutellar shield transverse, triangular; surface punctate and setose. Elytra with sides subparallel; with lateral margins very narrow but entirely visible from above; surface with single size punctures ( Fig. 2I ), elytral epipleuron comparatively narrow, 1.5 times as wide as corresponding metaepisternum, incomplete apically ( Fig. 2A ), inner margin with border area narrow throughout and border line fading before base of elytron. Metaventrite with discrimen long but incomplete anteriorly; metaventral postcoxal lines distinctly separated at middle, laterally complete and recurved; metaepisternum with external process interlocking with fovea on elytron; metaepimeron indistinct.

LEGS. With trochanters angulately produced ( Fig. 2A , G–H); tibiae without visible apical spurs; fore and mid tarsal claws appendiculate ( Fig. 2C ); metatarsal claws with quadrate basal tooth ( Fig. 2D ).

ABDOMEN ( Figs 2H , 4A ). With five ventrites, ventrite 6 partially visible; ventrite 1- 1.6 times as long as ventrite 2; abdominal postcoxal lines separate medially, recurved and complete anteriorly, deep, posteriorly almost reaches ventrite 2; hind margin of ventrite 5 covered with long setae and deeply emarginate; hind margin of ventrite 6 weakly emarginate, tergite VIII widely truncate apically ( Fig. 4B ).

MALE TERMINALIA AND GENITALIA ( Figs 4C , 5 A–D). Sternite IX with central part membranous ( Fig. 4C ); apodeme of male sternum IX with its apical half rod-like, base of spiculum broadly widened. Penis base with outer arm reduced, inner well developed; penis apex as in Fig. 5 A–B. Parameres ( Fig. 5 C–D) articulated with phallobase, well developed, simple and separated, slightly longer than penis guide, with apices covered with long setae; penis guide simple, subtriangular in inner view, without additional processes, with acute apex and lateral sides symmetrical throughout and pointed apex; tegminal strut simple, slightly expanded at apex.

Female. Not known.

Distribution

Papua New Guinea: Mt Wilhelm.

Figures

Fig. 1. Habitus of new species of Rhyzobius spp. (holotypes). A–D. R. albinos sp. nov., ♂ (MNHN). E–H. R. atramentarius sp. nov., ♂ (MNHN). I–L. R. serratus sp. nov., ♂ (MNHN). A, E, I. Dorsal view. B, F, J. Ventral view. C, G, K. Lateral view. D, H, L. Frontal view. Scale bars = 0.5 mm.

Fig. 2. SEM images of Rhyzobius spp. (holotypes). A–I. R. albinos sp. nov., ♂ (MNHN). J. R. atramentarius sp. nov., ♂ (MNHN). A. Habitus, ventral. B. Antenna. C. Protarsal claws. D. Hind tarsal claws. E. Head, ventral. F. Pronotum. G. Pro-, meso- and metathorax, ventral. H. Abdomen, ventral. I–J. Details of elytral punctation. Scale bars: A = 1.00 mm; B = 0.2 mm; C–D = 0.1 mm; E–F = 0.3 mm; G = 0.4 mm; H–J = 0.5 mm.

Fig. 4. Abdomens and male terminalia of Rhyzobius spp. A–C. R. albinos sp. nov. D–F. R. atramentarius sp. nov. G–I. R. serratus sp. nov. A, D, G. Abdomen. B, E, H. Abdominal segment VIII, ventral. C, F, I. Male genital segment, dorsal. Scale bars: A, D, G = 0.5 mm; B–C, E–F, H–I = 0.2 mm.

Fig. 5. Male and female genitalia of Rhyzobius spp. A–D. R. albinos sp. nov. E–I. R. atramentarius sp. nov. J–M. R. serratus sp. nov. A, E, J. Penis, lateral. B, F, K. Apex of penis. C, G, L. Tegmen, inner view. D, H, M. Tegmen, lateral. I. Female genitalia. Scale bars: 0.2 mm.