Trionymus bocheri, Gertsson & Hodgson

Gertsson, Carl-Axel & Hodgson, Chris, 2005, Four new species of mealybug (Pseudococcidae) and a new species of soft scale (Coccidae: Coccoidea: Hemiptera) from Greenland and redescriptions of a mealybug and a soft scale from Arctic Canada, Zootaxa 897, pp. 1-24 : 8-11

TRIONYMUS BOCHERI Gertsson & Hodgson spec. nov. ( Fig. 3 )

(Described from 1 specimen in good condition but missing all but 1 complete leg and 1 antenna).

Unmounted material. Not known.

Mounted material. Elongate oval in outline, 3550 µm long and 1575 µm wide; anal lobes rounded and moderately sclerotised; antennae 8 segmented; legs relatively quite short; circulus small and round; with 2 pairs of distinct cerarii; oral rim ducts absent.

Dorsum. Membranous; setae rather few and quite short, each mainly 13–25 µm long but with some on head up to 50 µm. Trilocular pores frequent and fairly evenly distributed. Simple (discoidal) pores scarce throughout; also with 1 small convex pore dorsad to each scape. Cerarii clearly present on abdominal segments VII and VIII, each with two stout spinose setae (stoutest on VIII), length of cerarian setae on VIII 16–18 µm, those on VII about 13 µm; with 9 or 10 auxiliary setae, longest about 55–60 µm. Anal lobe distinctly sclerotised, with about 20–22 trilocular pores on each sclerotised area. Ostioles membranous, each lip of posterior pair with 6–8 trilocular pores, no setae; anterior pair with no pores on anterior lips and about 5 on posterior lips, no setae. Oral rim ducts absent. Oral collar ducts of two sizes; larger ducts (each about 4 µm wide, 8 µm long, without a thin inner ductule) frequent throughout; smaller ducts (each about 1.5–2 µm wide, 6–7 µm long, with a long thin inner ductule) very scarce on abdominal segments only. Multilocular disc­pores each 10 µm wide, present as follows: VIII 2; VII 5 along posterior margin and 2 more medially; VI 1 post., 2 elsewhere; V 4 post. + 4 elsewhere, and IV 2. Anal ring 80 µm wide, with 6 setae, each about 100 µm long.

Venter. Membranous, with frequent fine setae, most clearly longer than those on dorsum, each 25–65 µm long, but some on head up to 75 µm; suranal setae 50 µm long; both long anal lobe setae broken off; each anal lobe with a small sclerotisation near base of anterior seta. Trilocular pores frequent and fairly evenly distributed. Simple (discoidal) pores as on dorsum. Oral rim ducts absent. Oral collar ducts of two sizes as on dorsum, both sizes present throughout but larger ducts most frequent on posterior abdominal segments, otherwise mainly along posterior margin of posterior abdominal segments; smaller ducts generally much less frequent, in a transverse line medially across segments II –VII and on each anal lobe; very scarce on thorax and head. Multilocular disc­pores each about 10 µm wide, present on abdomen as follows (approximate totals across segment): VIII 45 throughout segment; VII 40 along posterior margin and 40 elsewhere; VI 42 post., + 30 elsewhere; V 26 post. + 5 elsewhere; IV 10 post. + 1 elsewhere; III 0; II 1 medially; absent more anteriorly apart from 0–2 more or less laterad to posterior spiracles. Circulus small and oval, 36 µm wide and 23 µm long, without an intersegmental fold. Eyespot about 28 µm wide and 25 µm long. Antennae 8 segmented, 330 µm long; scape with 4 setae; pedicel with 5 setae + campaniform pore; segments III –VII each with usually 4 or 5 setae; preapical segment also with a fleshy seta; apical segment longest, with 8 hair­like setae, 3 fleshy setae and about 7 stiff setae near apex; apical seta about 30 µm long. Clypeolabral shield about 180 µm long; labrum about 85 µm long, with 11 pairs of setae. Spiracles: width of peritremes, anterior 26–30 µm; posterior 40–42 µm. Metathoracic legs (only part of 1 leg present): lengths (µm): coxa 140; trochanter + femur 232; number of setae on metathoracic leg: coxa 6 + 2 at base; trochanter 6; femur 10. Measurements of prothoracic leg: coxa 116; trochanter + femur 207; tibia 125; tarsus 75; claw 22; number of setae: coxa 8 (only 1 basally); trochanter 5 (long trochanter setae 75 µm); femur 13; tibia 8 + 2 spurs, each 16–18 µm long; tarsus 7; translucent pores on metacoxae few, none on metafemur. Tarsal digitules: one thinner and slightly shorter than other but both capitate and longer than claw; claw digitules both slightly longer than claw and capitate; claw without a denticle. Vulva obvious, between segments VII and VIII.

Material examined. HOLOTYPE Ψ: GREENLAND: Narsarsuaq, 1991, in pit­fall trap, J. Böcher ( ZMUC): 1 / 1 adΨ.

Comment. The adult female of T. bocheri spec. nov. is very similar to those that of T. perrisii (Signoret) , but differs (character­states on T. perrisii in parentheses) mainly in (i) the complete absence of multilocular disc­pores on the dorsum anterior to abdominal segment IV (present sparsely throughout dorsum) and (ii) their almost complete absence ventrally anterior to abdomen (present sparsely on thorax and head).

T. bocheri differs most obviously from T. elymus , described as new above, in having a small, almost round and slightly sclerotised circulus, without an intersegmental membrane. This type of circulus is also found on T. thulensis Green (another Trionymus species known from Greenland), from which it differs (character­states on T. thulensis in brackets) in having (i) some multilocular disc­pores on the abdominal dorsum (absent) and (ii) oral collar ducts of 2 sizes on dorsum (of one size only).

Etymology: this species is named after Dr. Jens Böcher, The Zoological Museum, University of Copenhagen, Denmark, who collected so much of the material seen during this study.

Figures

FIGURE 3. Adult female of Trionymus bocheri Gertsson & Hodgson. Labels etc as on Fig. 1.