Urothrips calvus, Tong, Xiaoli & Zhao, Chao, 2017

Tong, Xiaoli & Zhao, Chao, 2017, Review of fungus-feeding urothripine species from China, with descriptions of two new species (Thysanoptera: Phlaeothripidae), Zootaxa 4237 (2), pp. 307-320 : 316-317

Urothrips calvus sp. n.

( Figs 23–30 )

Female. Apterous ( Fig. 23 ). Head and prothorax brown; pterothorax yellow, but mesothorax with brown areas anterolaterally and metathorax light brown laterally. Abdominal tergite I yellowish brown, tergites II–VIII yellow with brown markings laterally, tergite IX yellow with lateral margin brown, tube yellow with extreme apex brown. Antennae segments I–III yellow, IV–V yellowish brown. Fore coxae brown, froe femora brown with yellow apically, fore tibiae yellow; mid legs yellow, but coxae pale yellowish brown; hind legs brown, but femora and tibiae with extreme pale bases and apices; all tarsi pale yellow with a brown marking apically.

Head ( Figs 24, 25 ) slightly longer than wide, dorsal surface and cheeks strongly tuberculate; cheeks gradually widened towards base and constricted at base; head broadly rounded in front, without any longer cephalic setae on anterior margin. Eyes each with only 3 ommatidia dorsally; ocelli absent. Antennae 5-segmented (morphological segments III–V united) ( Fig. 26 ), segment III longest, with indistinct suture between morphological segments, segment V with an incomplete suture between morphological segments VII and VIII; antennal segment III with 3 sense cones (morphological segment VI with 2 sense cones and V with 1). Maxillary stylets retracted to eyes, about one-eighth head width apart medially.

Pronotum ( Fig. 24 ) transverse, approximately 1.8 times as wide as long, dorsal surface sculptured with irregular wrinkles medially and being surrounded by small tubercles; pronotum with a pair of prominent epimeral setae ( Fig. 24 ), slightly dilated at apices; epimeral suture incomplete. Basantra present laterally but weak and membranous submedially; ferna well-developed ( Fig. 27 ). Meso- and metanotum weakly sculptured medially, metaepimera slightly swollen, with small tubercles but lacking any epimeral setae; mesopresternum reduced and membranous; anterior margin of mesoeusternum with a longitudinal median split ( Fig. 27 ); meso- and metafurcae placed laterally and widely separated ( Fig. 27 ). Legs short and tuberculate; fore tarsus without humus, hind tarsi each with a dorsal claw.

Abdomen broadest at segment II and tapering evenly to the tube. Abdominal tergite I transverse and distinctly sculptured, closely fused to tergite II ( Fig. 28 ), and clearly separated from metanotum; tergite II with two pairs of minute posteromarginal setae and a transverse row of 18–20 minute setae, posterolateral setae minute with similar size as postermarginal setae; tergites III–VIII each with a pair of well-developed spatulate posterolateral setae ( Fig. 29 ), and intermediate tergites each with three pairs of short posteromarginal setae and a transverse row of 14–20 minute setae; tergite IX near 1.8 times as long as maximum wide, slightly shorter than head. Tube about 9 times as long as apical width, about 1.3 times as long as head; tube with 6 terminal setae apparently equal in length, anal setae 2.8 times as long as tube.

Measurements (holotype female in microns). Total distended body length 1310. Head length 188, maximum width 175. Pronotum length 110, median width 200, epimeral setae 13. Abdominal tergite IX length 175, maximum width near base 100 and distal width 45. Tube length 245, basal width 23 and apical width 28. Antennae segments I to V length (width) as follows: 20 (25), 30 (30), 95 (26), 23 (18), 38 (15). Anal terminal setae about 600.

Male. Unknown.

Specimens examined. Holotype female (in SCAU): CHINA, Jiangxi: Jinggangshan City, Jinggangshan National Nature Reserve (114°7′4″E, 26°37′23″N, alt. 1240m), in leaf litter of Cryptomeria fortunei (Taxodiaceae) , 26.viii.2015 (Chao Zhao) . Paratypes (in SCAU): 8 females, collected with holotype.

Distribution. China (Jiangxi).

Etymology. The specific epithet, calvus , is from the Latin adjective, meaning “bald-headed”, in reference to the anterior margin of head without any cephalic setae.

Comments. This new species differs from most species placed in Urothrips in having antenna 5-segmented (morphological segments III–V united), eyes reduced to only 3 ommatidia, the meso- and metafurcae placed laterally and widely separated, and anterior margin of mesoeusternum usually having a longitudinal median division. Although U. kobroi Ulitzka & Mound is similar to U. calvus by sharing antenna with 5 segments, the following combination of characteristics readily distinguish that species from calvus : (1) eyes with about 8 facets dorsally; (2) pronotal epimeral setae minute; (3) fore tarsi with a sharply recurved hamus on external margin; (4) mesoeusternum anterior margin entire; (5) abdominal tube slightly longer than segment IX. Although the appearance and color pattern of U. calvus are similar to Stephanothrips species, particularly to S. austrinus , U. calvus lacks any prominent cephalic setae on the anterior margin of the head, in contrast to all Stephanothrips species.

Figures

FIGURES 23 – 29. Urothrips calvus sp. n.: (23) habitus of female; (24) head and thorax; (25) head; (26) antenna; (27) ventral view of thorax; (28) meso- and metanotum, abdominal tergites I – II; (29) abdominal tergites I – III.

FIGURE 30. Distribution map of Stephanothrips species in China.