Kirlia aphid (Chaitoregma kirlia) from China named a character from Pokémon series

NEWS - Kirlia aphid (Chaitoregma kirlia sp. nov.) from Fujian (Mount Wuyishan) and Guangdong (Mount Lianhuashan), China, has a pair of front horns that eat bamboo and is nicknamed “kirlia”, a character from the popular Pokémon series, in honor of the graceful and elegant nature of this new species.

Chaitoregma Hille Ris Lambers & Basu 1966 with Oregma tattakana Takahashi 1925 as the type species is a small genus in the Cerataphidini (Aphididae, Hormaphidinae). Currently only 2 species and 1 subspecies (non-nominotypical): Chaitoregma tattakana tattakana (Takahashi, 1925), Chaitoregma tattakana suishana (Takahashi, 1929) and Chaitoregma aderuensis (Takahashi, 1935).

C. kirlia forms large colonies on the underside of host leaves and may be inhabited by ants, Crematogaster sp. In the wild, it has been observed that in addition to the purple individuals of this new species in the colonies, there are sometimes a few yellow individuals that are thought to be mixed colonies with another Chaitoregma species, possibly C. tattakana suishana.

The new species resembles the type species C. tattakana, but C. kirlia has distinct wax gland plates on the abd. I–VI margins, (vs. no distinct wax gland plates in the other species). Larger distance between the crests of the frontal horns, 0.109–0.135 mm (vs. 0.098–0.110 mm in C. tattakana tattakana).

Length of setae on the dorsum of the head: 0.050–0.066 mm, abd. tergite I: 0.035–0.059 mm and VIII: 0.042–0.072 mm (vs. 0.079–0.112 mm; 0.056–0.113 mm; 0.062–0.096 mm). HT 0.22–0.26 × body length (vs. 0.25–0.30×), PT 0.4–0.68 × Ant.IV (vs. 0.27–0.48×), URS 0.78–1.04 × URS_BW (vs. 1.16–1.43×), URS 0.60–0.75 × 2HT (vs. 0.54–0.58×). The number of setae on different body parts also differs.

C. kirlia differs from C. aderuensis by at least 0.26–0.30 mm HT (vs. 0.37 mm in C. aderuensis) and 0.18–0.21 mm WA (vs. 0.23 mm).

Genetic distance thresholds have been used as a basis for species classification within the aphid group, with the general range being from 2% to 2.5%. The K2P distance between C. kirlia and other species is about 7.19–7.61%. This significant genetic distance exceeds the general range of thresholds and supports C. kirlia as a distinct species.

DESCRIPTION

Apterous viviparous female: body oval, dark purple in life. Body dorsum slightly covered with white wax powders, marginal areas on body with undeveloped flaky wax powders in life.

Mounted specimens. Body oval and dark sclerotic, 1.62–1.82 × as long as its width, sclerotic areas evenly covered with numerous irregularly shaped wax facets, wax facets arranged radially at the intersegmental area. Head and pronotum fused, mesonotum, metanotum, abdominal segments I and VIII mutually free; abdominal segments II to VII completely fused, sutures not clearly distinct.

Head. Fronts with a pair of frontal horns, frontal horns cylindrical with broadly rounded tips, about 1.2–1.7 × as long as their basal width, smooth, with 6–12 short setae. Distance between the apex of the horns about 0.109–0.125 mm. Embryo with blunt frontal horns. Antennae 4-segmented, sometimes 5-segmented, about 0.15–0.19 × body length; length in proportion of segments I–IV: 25–37, 25–30, 64–73, 40–52, and 18–27. Antennal setae all fine, long with acute apices; segments I–V with 1–2, 2–3, 3–6, 1–2 setae, respectively; apical part of processus terminalis with 2–5 setae. Length of setae on segment III 0.02–0.045 mm. Segment III narrowed toward base, sensorium very small. Eyes with 3 facets in apterae. Rostrum short, reaching or nearly reaching mid-coxae; URS wedge-shaped, about 0.60–0.75 × of second joint of hind tarsi, with 3 pairs of long primary setae. Dorsal head and pronotum with 15–20 setae, 0.050–0.066 mm, fine wavy, with acute apices.

Thorax. Margin of the pronotum to metanotum each with some wax facets. Dorsal setae on thorax similar to head setae. Pronotum with 2 pairs of spinal setae and 2 pairs of marginal setae; mesonotum, and metanotum each with 2 pairs of spinal, 1–2 pairs of pleural and 2 pairs of marginal setae, respectively. Mesosternal furca with 2 separated arms, each arm 1.53–2.47 × as long as basal diameter of antenna segment III. Legs short, trochanters nearly fused with femora; hind tibia 0.22–0.26 × long axle body. Setae on legs fine and slightly long; setae on hind tibia 0.90–1.27 × as long as its diameter. First tarsal chaetotaxy: 4, 3, 2. The first fore tarsal joint of the legs with 2 long setae and 2 short setae, while the first hind tarsal joint with 2 long setae.

Abdomen. Abdominal tergites I–VII each with 1 pair of wax gland plates on marginal sclerites, composed with irregularly shaped to rounded wax gland facets, surrounding 1 marginal seta, wax gland facets composed with 2–5 facets. Abdominal tergites I–V each with 2 pairs of spinal setae, 2–4 pairs of pleural and 1 pair of marginal setae; tergites VI with 1 pair of spinal, 1 pair of pleural and 1 pair of marginal setae; tergites VI with 1 pair of spinal and 1 pair of marginal setae; tergite VIII with 8–16 setae, setae on abdominal tergite VIII 2.9–3.7 × as long as basal diameter of antennal segment III. Spiracles round, open. Siphunculae pore-like, about 0.03 mm, slightly elevated, not situated on setaceous cones. Cauda knobbed and constricted at base, with about 3–7 setae. Anal plate bilobed, with 5–7 setae on each lobe. Genital plate with 4 anterior setae and 7–9 posterior setae. Gonapophyses two, each with 5–7 setae.

Original research

Wang Y, Huang X (2024). Taxonomic notes on the genus Chaitoregma (Hemiptera, Aphididae, Hormaphidinae), with description of a new species from China. ZooKeys 1218: 35-47, DOI:10.3897/zookeys.1218.133287

Dlium theDlium