Trionymus icelandensis Gerő & Szita, 2025

Gerő, Kornél, Alfreðsson, Matthías & Szita, Éva, 2025, New data on the scale insect (Hemiptera, Coccomorpha) fauna of Iceland, with description of a new species, ZooKeys 1236, pp. 119-128 : 119-128

Trionymus icelandensis Gerő & Szita sp. nov.

Fig. 1

Material examined.

Holotype • 1 adult ♀ mounted singly on a slide; left label: NSII 113860 / PPI 13482 (work) / ICELAND / Vík í Mýrdal / 63°25'13"N, 18°59'58"W / 15 Sep. 2022 / Festuca vivipara ; right label: Trionymus / icelandensis / Gerő & Szita / 1 ♀, holotype / Leg. K. Gerő / Det. É. Szita . Paratype • 1 adult ♀ mounted singly on a slide; ICELAND, Vík í Mýrdal ; 63°25'12"N, 19°00'06"W; 16 Sep. 2022; K. Gerő leg.; Poa pratensis ; NSII code: 113859; PPI work code: 13481 . (Both holotype and paratype are deposited in NSII)

Description.

Unmounted adult female. Body elongate oval, light yellow, covered with fine powdery wax.

Slide-mounted adult female. Body elongate oval, 1.68–1.69 mm long, 0.83–0.86 mm wide. Eyes marginal, each 24–26 μm wide. Antennae each 6 segmented, 258–264 μm long in total. Length of antennal segments: 1 st 36–43.2 μm, 2 nd 31.2–36 μm, 3 rd 38.4–43.2 μm, 4 th 19.2 μm, 5 th 24–28.8 μm, 6 th 72.8–79.2 μm, segments nearly parallel sided. Apical segment with 1 apical seta, 32–34 μm long; with 4 subapical setae, each 30–32 μm long, and with 5 fleshy setae, each 32–35 μm long. 5 th segment with 1 fleshy seta, 32 μm long. Other setae throughout the segments hairlike, slightly curved with fine tip, 25–40 μm long. Clypeolabral shield not visible. Labium 3 segmented, 80–91 μm long, 81–82 μm wide, 5 or 6 setae each 12–20 μm long. Anterior spiracles each 36–38 μm long, and about 14 μm wide across atrium; posterior spiracles each 40–42 μm long, and about 15 μm wide across atrium. Legs well developed; hind leg without translucent pores, segment lengths (in μm): coxa 68–75; trochanter + femur 165–168; tibia + tarsus 207–210; claw 22–23. Ratio of lengths of tibia + tarsus to trochanter + femur 1: 1.23–1.27; ratio of lengths of tibia to tarsus 1: 1.14–1.27; ratio of lengths of hind trochanter + femur to greatest width of femur 1: 2.37–2.65. Tarsal digitules hairlike, each 27–30 μm long. Claw digitules capitate, 24–25 μm long. Both pairs of ostioles present, lips not sclerotized; anterior ostioles each with a total for both lips of 5–8 trilocular pores and no setae; posterior ostioles each with a total for both lips of 7 or 8 trilocular pores and no setae. Anal ring 74–75 μm wide, with two complete rows of pores, the outer row with spiculae, ring bearing 6 setae, each seta 110–130 μm long.

Dorsum. Derm membranous; with two pairs of cerarii on last abdominal segments. Setae flagellate, slightly curved, of 3 sizes: small setae each 12–15 μm long; mid-sized setae each 19–23 μm long; and longest setae each 27–30 μm long. Longest setae distributed mainly marginally, others scattered throughout. Trilocular pores numerous throughout, each about 3.2 μm in diameter. Oral collar tubular ducts of one size, outer ductule 4 μm wide, 6.5 μm long. Multilocular disc-pores absent.

Venter. Derm membranous; one small circulus, present on middle of abdominal segment III, 24 μm long and 26.4 μm wide. Apical seta on each anal lobe 130–132 μm long. Body setae flagellate, slightly curved, in 4 sizes: shortest setae each 11–14 μm long, present throughout; middle-sized setae each 25 – 26 μm long, present throughout; second longest setae each 40–43 μm long, situated on margins of abdomen and a few present in medial zone of abdomen; and longest setae each 66–80 μm long, situated medially on head. Trilocular pores numerous, each about 3.2 μm in diameter. Oral collar tubular ducts of one size, same as on dorsum. Multilocular disc-pores, each about 8 μm in diameter with 10 loculi, numbering 2–8, present on abdominal segments III – VIII and occasionally also on mesothorax.

Diagnosis.

Trionymus icelandensis Gerő & Szita , sp. nov. can be recognised by possessing the following combination of features: (i) antennae each six segmented; (ii) eyes present; (iii) legs well developed, without translucent pores; (iv) one small circulus; (v) oral collar tubular ducts of one size present on both surfaces; (vi) multilocular disc-pores few, present on venter only, on abdominal segments III – VIII and occasionally on thoracic segment II; and (vii) body setae flagellate, in 3 sizes on dorsum, and in 4 sizes on venter, longest ones on venter of head.

Comments.

Trionymus icelandensis is similar to three other species of Trionymus . It resembles T. artemisiarum ( Borchsenius, 1949) in having two pairs of cerarii, lacking multilocular pores on dorsum, and in having 6 - segmented antennae; however, it differs as follows (character states of T. artemisiarum are given in brackets): (i) having one circulus (circulus absent); (ii) oral collar tubular ducts of one size (two sizes); and (iii) hind coxa without translucent pores (translucent pores present).

Trionymus icelandensis resembles T. massiliensis (Goux, 1941) in lacking multilocular pores on dorsum; however, it differs as follows (character states of T. massiliensis are given in brackets): (i) having two pairs of cerarii (one pair); (ii) one circulus (circulus absent); (iii) oral collar tubular ducts of one size (two sizes); (iv) hind coxa without translucent pores (translucent pores present); and (v) antennae each with six segments (seven segments).

Trionymus icelandensis resembles T. thulensis Green, 1931 in having two pairs of cerarii, one circulus, and in lacking multilocular pores on dorsum; however, it differs as follows (character states of T. thulensis are given in brackets): (i) having oral collar tubular ducts of one size (two sizes); (ii) hind coxa without translucent pores (translucent pores present); and (iii) antennae each with six segments (seven or eight segments).

Etymology.

The species is named in homage to the country of Iceland; the epithet is formed by the combination of the island name, Iceland, with the Latin suffix “ - ensis ”, meaning “ originating from ”.

Distribution.

Iceland.

Host plants.

Poaceae : Festuca vivipara , Poa pratensis .

Scale insect species list for Iceland

With this study, the total number of scale insect species with breeding populations recorded in Iceland was increased to ten species (Table 1 ). Of these, seven species can be found in outdoor conditions, three are indoor species. Five species were found exclusively on imported fruits and are not considered to be established in Iceland (Table 2 ).

Figures

Figure 1. Trionymus icelandensis Gerő & Szita, sp. nov., holotype female. On antenna and legs, ventral setae are coloured grey, and dorsal setae are black.