Unilobothrips, Nakahara, Sueo & Foottit, Robert G., 2012

Nakahara, Sueo & Foottit, Robert G., 2012, Review of Chirothrips and related genera (Thysanoptera: Thripidae) of the Americas, with descriptions of one new genus and four new species, Zootaxa 3251, pp. 1-29 : 24-27

Unilobothrips gen.n.

Type species: Unilobothrips cornuatus sp.n.

Female. Macropterous. Antennal segment I not enlarged, segment II asymmetrical, segments III and IV each with forked sense cones. Head with truncate, interantennal process with short subapical tooth on each side, longer than and as wide as antennal segment I ( Fig. 53 ); lateral margin of vertex anterior of compound eyes rather straight then broadly curved above antennal socket, spine-like setae anterior of fore ocellus; venter of head with cluster of longer spine-like setae between compound eyes ( Fig. 54 ) Pronotum subtrapezoidal, with 2 pairs of posteromarginal setae; discal setae few; basantra membranous, without setae; prospinasternum a transverse band with conical spina. Mesonotum with bristle-like setae, submedian setae far anterior of posterior margin, posterior setae far anterior of posterior margin and slightly behind submedian setae; mesosternal furcal invaginations fused. Metanotum with 2 pairs of bristle-like setae. Fore wing with costal setae. Abdominal tergites with few setae; posteromarginal flange short, as conical teeth submarginally, medially as low lobes ( Fig. 59 ); sternites with posteromarginal setae; ovipositor well developed, about 170 µm.

Male. Brachypterous. Head with conical, interantennal process shorter than antennal segment I ( Fig. 58 ); abdominal sternite with glandular area.

Etymology. Composed from Latin “uni” (one), “lobus” (lobe) and “ thrips ” (common name of Thysanoptera ). The female of this monotypic genus has an elongate, truncate interantennal process.

Comments. The females have an elongate interantennal process with truncate apex which is not found in the other chirothripine genera. Moreover, a cluster of small, spine-like setae on the venter of the head of females of this genus is found only in some members of the Arorathrips .

Unilobothrips cornuatus sp. n. ( Figs 52–67 )

Female. Macropterous. Body brown; legs brown except all tarsi yellow, fore tibiae yellowish brown distally; ocellar crescent not seen; body setae pale brownish yellow; fore wings light yellowish brown; antennae brown except apex of segment II yellow, III with pedicel yellow and rest of segment yellowish brown.

Antenna ( Fig. 52 ): Segment I smaller than segment II, with dorsal transverse ridge; segment II slightly asymmetrical; segments III–V about as long as wide; segment VIII longer than VII; forked sense cones on segments III and IV, segment VI with inner sense cone in anterior 1/2, extending to segment VII.

Head ( Figs. 53, 54 ): Prolonged anterior of eyes; interantennal process broad, truncate at apex, with rounded tubercle or broad tooth-like process on each side, wider than segment I, extending to about midlength of segment II; lateral margin of vertex anterior of compound shorter than length of occiput; compound eyes about twice as long as occiput; transverse striae on occiput, absent between and anterior of compound eyes; 17 (16) short, spine-like setae cephalad of fore ocellus, ocellar setae between anterior and posterior ocelli, postocular seta minute, 1 just caudad of posterior ocelli, 2 just caudad of compound eyes; 22 (20) ventral setae in addition of normal setae, slightly longer than those on dorsum; mouthcone with broadly rounded apex.

Pronotum ( Fig. 55 ): Posterior part wider than anterior part, wider than long, completely sculptured with anastomosing lines; about 79, short, rather stout discal setae, 5–10 µm long, in broad median and submarginal bands; 2 pairs of well developed posteroangular setae, 11 posteromarginal setae, median pair slightly longer than others. Prosternum ( Fig. 58 ) with basantra finely granulose, lacking setae; ferna well developed, divided; prospinasternum strap-like, with produced spina. Mesonotum ( Fig. 56 ): sculptured with transverse lines and reticulations, striae lacking minute teeth; 2 anteromedial campaniform sensilla present; median setae far anterior of posterior margin, posterior setae far anterior of margin slightly behind median setae; 65 sternal setae present. Mesonotum without spinula ( Fig. 58 ). Metanotum ( Fig. 57 ): reticulated, median setae slightly caudal of anterior margin, about as long as lateral setae; 2 campaniform sensilla in posterior 1/3 of notum; 28 sternal setae present. Fore legs: Well developed, apical margin of femora not reflected, apex of tibiae truncate.

Fore wings: Rather straight, tapering to a blunt apex; 22 (19) costal setae, those at midlength about as long as width of wing; 24 (20) slightly wavy anterior fringe cilia; fore vein with 6 (4) setae in proximal 1/2, 2 setae in distal 1/2; hindvein with 5 (5) setae; scale with 5 marginal and 1 discal setae.

Abdomen: Tergites ( Fig. 59 ) transversely sculptured; median setae on tergite I minute, median setae on anterior 1/2 on tergites II–VIII, slightly anterior of median campaniform sensilla, slightly shorter to about as long as D2 setae; posteromarginal flange as lobes medially, submarginally and laterally with teeth; tergite IX shorter than XI with 2 pairs of campaniform sensilla, B1 setae slightly longer than tergite X; tergite X almost or completely divided by dorsal split. Pleurotergites ( Fig. 60 ) with posteromarginal teeth. Sternites ( Fig. 60 ) transversely sculptured; sternite I with anteromedial setae; sternite II with 2 pairs of posteromarginal setae, sternites III–VII with 3 pairs, median pair on VII slightly cephalad of posterior margin margin, closer to B2 setae than to each other; low posteromarginal lobes on sternites II–VI, more distinct on anterior sternites; ovipositor about 185 µm long.

Measurements of holotype female (and female paratype): Body length 1.37 mm, 1.91 mm distended. Other measurements in µm. Antenna: total length 220 (213); length and width of antennal segment I 24 (27), 24 (24); II 30 (3l), 30 (28); III 35 (32), IV 33 (35), 37 (32); V 32 (32), 30 (32); VI 37 (371, 35 (37); VII 10 (8), 10 (7); VIII 15 (12), 5 (5). Head: length from interantennal process 151 (141); lateral margin cephalad of compound eye 12 long; compound eye 62 (67) long; occiput 24 (24) long. Pronotum 215 (200) long, 254 (235) wide. Fore wings 902 (783) long, 54 (50) wide at midlength. Abdominal segment IX 64 (62) long, X 91 (86) long. Setal lengths: pronotal discal setae 7–10 long, posteroangular setae outer pair 40–50 (42), inner pair 42–47 (35–37), posteromarginal median pair about 10 long; metanotal median setae 27 long, lateral setae 37 long; abdominal tergite IX with B1 setae 100 (84) long, B2 setae 104 (89) long, tergite X with B1 setae 86 (84) long.

Male. Brachypterous. Similar to female in coloration.

Antenna ( Fig. 61 ): Segment II asymmetrical, segment III apparently with simple sense cone, segment IV with main sense cone simple, a well developed simple sense cone on outer margin.

Head ( Fig. 62, 63 ): Longer than wide, prolonged anterior of eyes; interantennal process conical, ventrally with tooth on each side near apex, apex resembling a "rounded, sclerotized cap”, narrower and shorter than than antennal segment I; antennal base reduced, lateral part resembles a tooth; compound eye with 2 pigmented ommatidial facets; ocelli absent; 7 setae on vertex; ocellar setae posterior of and separated from setae on vertex; 2 short, postocular setae on each side just caudad of eyes; venter with normal, bristle-like setae in contrast to female.

Pronotum: Transversely sculptured; 32 discal setae in 2 submedial rows and on submargins, 2 developed posteroangular setae, 8 posteromarginal setae. Mesonotum: Similar to that of female. Metanotum ( Fig. 64 ): Subrectangular with transversely oriented sculpturing; median and lateral setae posterior of anterior margin; 2 campaniform sensilla in about midlength as widely separated as median setae.

Fore wing: Brachypterous.

Abdomen: Tergite IX ( Fig. 65 ) with B1 setae posteromediad of longer Dl setae, B2 setae closer to long, posterolateral setae than to B1 setae; campaniform sensilla between B1 and B2 setae, another pair anterior of Dl setae near anterior margin. Abdominal sternites III ( Fig. 67 ) and IV each with circular glandular area, 27 µm wide, 24 µm long on III, slightly larger on IV.

Measurements of male paratype. Body length 1.38 mm distended. Other measurements in µm. Antenna: Total length 169; length and (width) of segment I 17 (24); II 24 (22); III 30 (21); IV 30 (22); V 24 (17); VI 37 (17); VII 7 (7); VIII 10 (5). Length of head from interantennal process 114, eye 50, occiput 31. Pronotum 148 long, 178 wide. Setal length: pronotal posteroangular setae outer pair 24, inner pair 35–37 long; on abdominal tergite IX Dl setae 37 long, B1 setae 12 long, B2 setae 10 long.

Type material. Holotype female ( CAS), 1 female and 1 male paratype: Three Forks (on Madison River), Gallatin Co., Montana, sweeping, 23-VII-83, J. D. Pinto (UCR-83-125) ( CAS).

Distribution. United States (MT).

Etymology. Specific epithet from Latin “ cornuatus ”, horn-like, in reference to the horn-like interantennal process of this species.

Comments. No other North American species has a long interantennal process.

Figures

FIGURES 52 – 60. Unilobothrips cornuatus sp. n., holotype female. (52) right antenna, dorsal aspect; (53) head, dorsal aspect; (54) head ventral aspect; (55) pronotum; (56) mesonotum; (57) metanotum; (58) pro- and mesosterna; (59) abdominal tergite IV; (60) abdominal segment VI, sternites and pleurites. Scale bar 100 μm.

FIGURES 61 – 67. Unilobothrips cornuatus sp. n., male paratype. (61) right antenna, dorsal aspect; (62) head, dorsal aspect; (63) head, ventral aspect; (64) metanotum; (65) abdominal tergites IX and X; (66) mesosternum; (67) abdominal sternite III. Scale bar 100 μm.