Holothrips Karny, 1911

Mound, Laurence A. & Tree, Desley J., 2014, Fungus-feeding phlaeothripine Thysanoptera in the genus Holothrips from Australia and New Caledonia, with a structurally similar new genus, Holoengythrips, Zootaxa 3860 (2), pp. 125-148 : 126-127

Holothrips Karny

Holothrips Karny, 1911: 502 . Type species Holothrips ingens Karny by monotypy.

Eleven generic names are currently listed as synonyms of this genus, and as a result it includes almost 130 species (ThripsWiki 2014). Okajima (1987) provided a generic diagnosis and a taxonomic account of 72 Holothrips species from the Old World, including three species from Australia. For the many New World species in this genus ( Mound & Marullo 1996) the only revisionary study is a key to 12 species from Mexico ( Johansen & Mojica 1994). The genus is placed in a subgroup of the Phlaeothripinae known as the Docessissophothrips genus-group ( Dang et al. 2014), together with a few related genera. One conclusion reached here is that the apparent length of the mouth cone may not provide a reliable distinction between species.

The Australian species of Holothrips share the following character states: Antennae 8-segmented but with the suture between VII–VIII variably incomplete or even absent and thus producing a 7-segmented condition; antennal segment III with 3 sensoria, IV with 4; maxillary stylets 3–6 microns wide, retracted to compound eyes, close together medially for full length of head, often with a small or large loop within the prothorax; pronotum transverse, with 5 pairs of major setae, notopleural sutures complete; fore tarsus with tooth in both sexes; fore wing parallel-sided, with duplicated cilia; metanotum usually with some small discal setae on anterior third, median setal pair weak; mesothoracic sternopleural sutures present, often long; pelta without campaniform sensilla; tergites II–VI with 2 pairs of wing-retaining setae, but anterior pair on each tergite often weakly developed, both pairs often weak or absent on VII; tergite IX major setae long, setae iS short; tube shorter than head, commonly yellow in part with grey terminal band; male sternites with no pore plate on VIII, sternites IV–VII commonly with paired areas of specialized reticulation.

Key to Holothrips species from Australia

1. Mesoeusternum anterior margin eroded medially with mesopresternum projecting posteriorly into this eroded area ( Figs 17, 18 ); inter-antennal distance 1.0–2.0 times as wide as antennal segment I ( Figs 1, 3 ); antennal segments VII–VIII with suture complete dorsally and ventrally.......................................................................... 2

-. Mesoeusternum anterior margin complete and transverse ( Figs 29, 30 ); inter-antennal distance less than 0.8 times as wide as segment I; antennal segments VII–VIII with suture varying, either absent or complete ventrally but usually not complete dorsally................................................................................................ 3

2. Inter-antennal distance at least 1.5 times width of segment I ( Fig. 3 ).................................... eurytis sp.n.

-. Inter-antennal distance 1.0 times width of segment I ( Fig. 1 ).............................................. australis

3. Body bicoloured, pterothorax brown laterally but paler medially, tergites II–VII brown with posterior margin yellow, tergites VIII–IX yellow; antennal segments I–II largely yellow............................................ lamingtoni sp.n.

-. Thorax and abdomen uniformly brown, antennal segment I usually brown......................................... 4

4. Mid and hind tibiae yellow in sharp contrast to brown femora.................................................. 5

-. Mid and hind tibiae brown to light brown, or yellow with brown shadings, but never sharply paler than femora........... 9

5. Apterous; metanotal sculpture of concentric reticulation ( Fig. 21 )..................................... circulus sp.n.

-. Macropterous or micropterous; metanotal sculpture different or absent........................................... 6

6. Antennal segment III no more than 1.8 as long as wide; postocellar setae long and capitate................... frerei sp.n.

-. Antennal segment III 1.9–2.1 times as long as wide; postocellar setae acute, usually shorter than length of one hind ocellus.. 7 7. Pelta broad, basal width more than 1.7 times median length ( Fig. 22 ); tube brown subterminally before terminal grey band.............................................................................................. bunyai sp.n.

-. Pelta elongate, basal width less than 1.3 times median length ( Figs 11, 12 ); tube yellow subterminally before terminal grey band............................................................................................... 8

8. Mouth cone long, projecting beyond rounded labium ( Fig. 30 ), extending across prosternum between fernal sclerites................................................................................................. speciosissimus

-. Mouth cone shorter, not projecting beyond rounded labium ( Fig. 29 )...................................... oceanicus

9. Postocular setae capitate ( Fig. 4 ); tube with sides straight and evenly tapering to apex ( Fig. 15 )............. federicae sp.n.

-. Postocular setae long and pointed; tube slightly constricted beyond widened base, and more sharply constricted at apex ( Fig. 16 )................................................................................................ 10

10. Antennal segment III brown, yellow only at extreme base, IV–VI uniformly brown; tube golden brown; fore wings distinctly shaded.................................................................................... notialis sp.n.

-. Antennal segment III yellow at least in basal half, IV–VI yellow at base ( Fig. 17 ); tube dark brown; fore wings very weakly shaded [ New Caledonia]....................................................................... lafoae sp.n.

Figures

FIGURES 17–24. Holothrips from Australia. Thoracic sternites 17–18: (17) australis; (18) eurytis sp.n. Pterothorax and tergites I–II 19–22: (19) australis; (20) federicae sp.n.; (21) circulus sp.n.; (22) bunyai sp.n. (23–24) notialis sp.n. pelta variation.

FIGURES 1–9. Holothrips from Australia. Heads: (1) australis; (2) bunyai sp.n.; (3) eurytis sp.n.; (4) federicae sp.n.; (5) circulus sp.n.; (6) frerei sp.n. (7) lamingtoni sp.n.; (8) notialis sp.n.; (9) lafoae sp.n.

FIGURES 25–33. Holothrips from Australia. Antenna 25–28: (25) bunyai sp.n.; (26) frerei sp.n.; (27) lafoae sp.n.; (28) lamingtoni sp.n. Mouth cone and thoracic sternites 29–30: (29) oceanicus; (30) speciosissimus. Male sternite VII 31–33: (31) australis; (32) lafoae sp.n.; (33) speciosissimus.

FIGURES 10–16. Holothrips from Australia. Pterothorax and tergites I–II 10–12: (10) frerei sp.n.; (11) speciosissimus; (12) oceanicus. (13) lafoae sp.n., tergites I–II. Tergite IX and tube 14–16: (14) circulus sp.n.; (15) federicae sp.n.; (16) notialis sp.n.