Aphis polaris Stekolshchikov & Khruleva, 2014, sp. nov.
Creators: name: Stekolshchikov, Andrey V.
name: Khruleva, Olga A.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Aphidomorpha
Aphididae
Aphis
Aphis polaris

description: Aphis polaris sp. nov.
(Figs. 9–15, 16–25, Table 2)
Type material. Holotype: apterous viviparous female, No. 10148, slide No. 1, “ Aphis polaris sp. n., Chukotka Autonomous Okrug, Iultinsky District, Wrangel Island, the middle course of the Mamontova River, 30.vii.2006, raised terraces with forbs-legume-dryad vegetation, leg. O.A. Khruleva”. Paratypes: 2 fund., No. 10140, from the same locality as holotype, Astragalus alpinus L., 10.vii.2006; 3 fund., No. 10141, from the same locality as holotype, 28.vi–9.vii.2006, pitfall traps; 19 fund., No. 10142, from the same locality as holotype, 9–19.vii.2006, pitfall traps; 1 fund., No. 10143, from the same locality as holotype, 12.vii.2006, sweeping; 1 ovip., No. 10144, Somnitel’nye Mountains, 14.vii–15.viii.2006, sand-pebbly river floodplain with moss-forbs-semishrub (dryad, dwarf willows) vegetation, pitfall traps; 1 ovip., No. 10145, Somnitel’nye Mountains, 16.vii–13.viii.2006, dampish bottom of a hill with shrub-grassy-moss vegetation, pitfall traps; 16 fund., 1 al. and 3 ovip., No. 10146, Somnitel’naya Bay, 16.vii–14.viii.2006, a zoogenic mesophytic meadow around an owl resting site, pitfall traps; 1 fund., No. 10147, from the same locality as holotype, 19.vii–2.viii.2006, pitfall traps; 3 fund., 1 apt., 1 al. and 1 ovip., No. 10149, from the same locality and the same data as holotype, Astragalus alpinus L.; 1 ovip., No. 10150, from the same locality as holotype, 31.vii–8.viii.2006, pitfall traps; 3 fund., No. 10278, Somnitel’naya Bay, Oxytropis sp., 9.vii.1989, moderate humid plain with moss-legume-forbs-shrub vegetation; 6 fund. and 4 ovip., No. 10282, Somnitel’naya Bay, 19–31.vii.1988, river valley with forbs-grass-shrubby (dryad, willow) vegetation, pitfall traps; 10 fund., No. 10284, from the same locality as holotype, 9–19.vii.2006, pitfall traps; 4 fund., No. 10285, Somnitel’naya Bay, 15.vi–16.viii.2006, a zoogenic mesophytic meadow around an owl resting site, pitfall traps; 2 fund., No. 10287, the upper course of the Neizvestnaya River, 5.vii–3.viii.2006 moderate humid ridges with moss-herb-shrub (dryad, hemi-creep willows) vegetation, pitfall traps; 1 fund., No. 10289, from the same locality as holotype, 8–20.vii.2006, pitfall traps; 2 ovip., No. 10291, from the same locality as holotype, Astragalus alpinus L., 30.vii.2006; 1 apt. and 1 ovip., No. 10292, from the same locality as holotype, Astragalus alpinus L., 30.vii.2006; 186 fund. and 2 apt., No. 10294, the lower course of the Tundrovaya River, 29.vi–19.vii.1989, sandpebbly river floodplain with moss-forbs-semishrub (dryad, dwarf willows) vegetation, pitfall traps; 120 fund., No. 10295, Somnitel’naya Bay, 30.vii–8.viii.1989, moderate humid plain with moss-legume-forbs-shrub vegetation, pitfall traps.
The apterous viviparous female is described in greatest detail. For the other morphs, the differences from the latter are pointed out.
The holotype of A. polaris sp. nov. is deposited at the Zoological Institute of the Russian Academy of Science, St. Petersburg, Russia (ZIN); paratypes and other materials are deposited at ZIN, the Natural History Museum, London, the United Kingdom, and the Muséum national d'Histoire naturelle, Paris, France.
Etymology. Specific epithet polaris is a Latin adjective meaning polar.
Description. Fundatrix. Body broad elliptical, 1.3–1.7 (1.4–1.6) times as long as wide. The living specimens are bluish-black. Pro-, meso-, and metanotum and all tergites of abdomen with more or less large sclerotized band; pro- and mesonotum with large marginal sclerites; metanotum and abdominal segments I–VII with small marginal sclerites, sometimes absent on one or several segments. Sclerotized bands on metonotum and tergites I–V often interrupted in the middle and seldom divided into very small, almost invisible separate sclerites, in which case band on pro- and mesothorax and on tergites VI–VIII not large, thin. Setae on dorsal surface of thorax and abdomen blunt or, rarely, pointed; marginal setae 0–2, 1–3, 1–3, 0–4, 1–3, 0–4 and 1–2 on each side of abdominal segments I–VII; abdominal tergite III with 0–4 (1.0–3.0) dorsal setae. Meso- and metathorax with 0–2 (0.0–1.6) marginal tubercles. Frontal tubercles not high, but clearly marked; median tubercle surpassing or, rarely, not reaching the level of antennal tubercles. Occipital and frontal setae on head blunt or, rarely, pointed. Antennae 5-segmented due to fusion of initial 3rd and 4th segments. Setae on antennae blunt or pointed; basal part of 5th antennal segment with 1–3 (1.8–2.1) setae, longest seta 0.86–1.38 (1.00–1.23) times as long as diameter of base of the segment. Ultimate rostral segment elongated wedge-shaped with slightly concave sides, 1.78–2.60 (2.07–2.43) times as long as its basal width. Ventral seta on hind trochanter 0.49–1.39 (0.59–0.94) times as long as basal diameter of hind femur. Chaetotaxy of first tarsal segments 3,3,2 and only sometimes one or both fore or middle tarsus with 2 setae. Second segment of hind tarsus 3.64–4.60 (3.73–4.24) times as long as its maximum width, with 0–2 (0.0–1.0) ventral setae in addition to the three apical pairs, dorsal setae absent. Arms of mesosternal furca connected by wide sclerotized stem. Siphunculi narrowing towards apex, with clear narrowing before flange, imbricate, with small flange. Cauda elongated-triangle or triangular. Hind tibia with 0–7 (0.0–2.1) rounded or oval pheromone plates.
Measurements of one specimen. Body—2051×1452, antennae—872: III—306×25 (in the middle), IV—180, V—109+134; hind femur—401, hind tibia—711; siphunculus—137×53 (in the middle); cauda—177×159 (at base) x 132 (before base). For more biometric data see Table 2.
Apterous viviparous female. Body elliptical, 1.5–1.8 (1.6–1.8) times as long as wide. Living specimens bluish-black. Cleared specimen with head, 1st antennal segment, 2nd–4th rostral segments, sclerites at base of coxa, coxa, trochanter, femur (except for its base), base and apex of tibia, bands and marginal sclerites on dorsum of thorax and abdomen, peritreme, siphunculus, subgenital and anal plates and cauda dark brown; 2nd–6th antennal segments, tibia, and tarsus brown. Pro-, meso- and metanotum and all abdominal tergites with sclerotized band; all segments of thorax and abdominal segments I–VII with marginal sclerites; the size and level of sclerification of these bands and sclerites variable, with most individuals intermediate; one specimens is almost totally sclerotized, the others have relatively smaller sclerotized parts and one weakly sclerotized (bands on abdominal tergites I–IV divided into sclerites and with thin and relatively short bands on all others tergites of body); in more heavily sclerotized specimens bands on tergites II–VI, or III–VI, or IV–VI fused anterolaterally in a sclerotized shield with a membranous area on the boundary between tergites. Surface of head smooth, weakly wrinkled; occiput and dorsal side of thorax and abdominal tergites I–VI distinctly reticulate (contours of cells formed by thick, irregular lines); tergite VII with rows of pointed spinules sometimes situated in form of cells; on tergite VIII spinules partially fused and forming short scales; ventral side of thorax slightly reticulate (contour of cells formed by thin, irregular line or by small pointed spinules); ventral side of abdomen with long rows of small spinules sometimes forming strongly stretched cells. Setae on dorsal thorax and abdomen pointed or blunt, not long; on ventral surface they are pointed or finely pointed; marginal setae 1, 2–3, 2–3, 2–3, 1–2, 1–2 and 1–2 on each side of abdominal segments I–VII; abdominal tergite III with 2–3 dorsal setae. Marginal tubercles always present on prothorax and abdominal segments I and VII and sometimes present on segments II–IV, number of marginal tubercles on abdominal segments II–IV 1–5 (3.0); marginal tubercles on prothorax and abdominal segments I and VII not large, strongly protuberant up to nipple-shaped and conical, on segments II–IV smaller, nipple-shaped. Head without trace of epicranial coronal suture. Frontal tubercles not high, weakly marked; median tubercle surpassing the level of antennal tubercles. Occipital and frontal setae on head and setae on antennae pointed or blunt. Antennae 6- segmented, without secondary rhinaria. Basal part of 6th antennal segment with 2–4 (2.8–4.0) setae, longest seta 0.88–1.29 (1.05) times as long as articular diameter of basal part of the segment. Rostrum reaching mesothorax. Ultimate rostral segment elongated wedge-shaped, 2.08–2.47 (2.19) times as long as its basal width. Legs strong, setae on legs pointed or finely pointed; ventral seta on hind trochanter 0.60–1.00 (0.77) times as long as basal diameter of hind femur. Chaetotaxy of first tarsal segments 3,3,2 and only one specimen with 2 seta on one fore leg. Second segment of hind tarsus 3.67–4.70 (3.81–4.46) times as long as its maximum width, with 1–3 (2.0) ventral setae in addition to the three apical pairs, dorsal setae absent. Siphunculi faintly narrowed to apex, imbricate, almost cylindrical, with clear narrowing before flange. Subgenital plate oval. Setae on anal plate finely pointed. Cauda elongated-triangle. One hind legs of one individual with a pheromone plate irregular to somewhat oval in shape.
Measurements of holotype. Body—2101×1188, antennae—1135: III—263×38 (in the middle), IV—197, V—210, VI—126+190; hind femur—462, hind tibia—843; siphunculus—164×54 (in the middle); cauda—190×163 (at base) ×132 (before base).
Alate viviparous female. Two considerably damaged specimens. The living specimens are bluish-black. Cleared specimen with head, thorax, 1st antennal segment, sclerite at base of coxa, coxa, trochanter, femur (except for its base), base and apices of tibia, bands, and marginal sclerites on dorsum of abdomen, peritremes, siphunculus, subgenital and anal plates, and cauda dark brown; 2nd–6th antennal segments brown; tibia light brown. Abdominal dorsum with two small sclerites on tergites I and V, bands on tergites VI–VIII and small marginal sclerites on I, V and VII abdominal segments and large marginal sclerites on II–IV and VI segments. Head, dorsal and ventral side of thorax and abdominal tergites I–V smooth, weakly wrinkled; abdominal tergite VI with sparse, large, pointed spinules sometimes situated on a contour of cells. Marginal setae 1, 2, 2, 2, 1–2, 1–2 and 1 on each side of abdominal segments I–VII. One marginal tubercle present on segments II–IV. Frontal tubercles clearly marked. Basal part of 6th antennal segment with 1–3 setae, longest seta 1.00–1.25 times as long as articular diameter of basal part of the segment. Third antennal segment with 8–10 secondary rhinaria on distal 2 / 3, 4th segment with 1–3 (0–0.2) and 5th segment with 0–1 secondary rhinaria; secondary rhinaria rounded or oval, larger rhinaria sometimes with a constriction as in a figure 8, weakly projecting. Ultimate rostral segment 2.24–2.35 times as long as its basal width. Ventral seta on hind trochanter 0.60–0.65 (0.63) times as long as basal diameter of hind femur. Second segment of hind tarsus 4.50–4.84 (4.67) times as long as its maximum width.
Measurements of one specimen. Fore wing—3208, antennae—1191: III—298×35 (in the middle), IV—223, V—200, VI—129+195; hind trochanter+femur—579, hind tibia—954, siphunculus—152×42 (in the middle); cauda—157×142 (at base) ×111 (before base). For more biometric data see Table 2.
Oviparous female. Body elliptical, 1.4–1.6 (1.5) times as long as wide. Pro-, meso- and metanotum with large sclerotized bands; band on metanothum often interrupted in the middle and sometimes divided into separate sclerites; bands on abdominal tergites I–VI always interrupted in the middle and often divided into large or small paired or unpaired separate sclerites; band on abdominal segment VII always divided into very small paired separate sclerites; band on tergite VIII often interrupted in the middle. Setae on dorsal surface of thorax and abdomen blunt, rarely pointed; marginal setae 1, 2–3, 1–3, 2–3, 1–4, 1–3 and 0–1 on each side of abdominal segments I–VII. Basal part of 6th antennal segment with 2–3 (2.6) setae, longest seta 1.08–1.45 (1.08–1.25) times as long as articular diameter of basal part of the segment. Ultimate rostral segment 1.63–2.37 (1.95–2.27) times as long as its basal width. Setae on legs blunt, pointed or finely pointed; ventral seta on hind trochanter 0.50–0.83 (0.57–0.83) times as long as basal diameter of hind femur. Second segment of hind tarsus 3.90–4.56 (3.95–4.56) times as long as its maximum width, with 1–3 (1.0–2.0) ventral setae in addition to the three apical pairs, dorsal setae absent. Cauda triangular or elongated triangle. Hind tibia with 20–57 (20.0–41.3) rounded or oval pheromone plates.
Measurements of one specimen. Body—1929×1274, antennae—951: III—211×30 (in the middle), IV—134, V—172, VI—129+167; hind femur—406, hind tibia—736; siphunculus—154×52 (in the middle); cauda—159×190 (at base) ×139 (before base). For more biometric data see Table 2.
Distribution. The species is known only from Wrangel Island.
Biology. Aphis polaris is the most common and widespread species of aphid on Wrangel Island. It was found in cold northern and southern coastal localities (the lower course of the Tundrovaya River, Somnitel’naya Bay, Rogers Bay) and in the central area of the island (the middle course of the Mamontovaya River). In the coastal areas, A. polaris occurred in river flood plains and in moderate humid stations on the plain with moss-forb-shrub and moss-forb-sedge assemblages. In the central part, this species was recorded but sporadic. Its abundance in well-defined habitats varied greatly from season to season. In the middle course of the Mamontovaya River in 1992, A. polaris was collected on the elevated terraces in forbs-legume-dryad associations with a high abundance of Astragalus alpinus L. and Oxytropis spp., but it was not recorded in this habitat in 1993 or 1994. In 2006, A. polaris was collected not only in this habitat, but also in different sites of the river valley. That same year it was also recorded in the upper course of the Neizvestnaya River and in the interior part of the Somnitel’nye Mountains, ~ 10 km from the coast.
Aphids were twice collected on Astragalus alpinus L. in 2006 and once on Oxytropis sp. in 1989. Most of the other specimens were collected from pitfall traps, thus exact dates of their appearance are uncertain. However, adult fundatrices appeared prior to July 9 (collection date of sample No. 10141) and persisted at least until the end of July (sample No. 10149, collected on July 30 from Astragalus alpinus L.). Moreover, the state of the collected individuals suggests this morph could also be found at a later time. The same sample also contained an oviparous female. Apterous viviparous females and one alate viviparous female were collected on the same day, July 30. Apparently, the life cycle of the new species is similar to the reduced life cycle of Acyrthosiphon svalbardicum Heikinheimo, 1968, which has been studied in detail (Strathdee et al., 1993; Strathdee & Bale, 1995; Hodkinson et al., 2002, etc.). In this Acyrthosiphon species, the fundatrix produces oviparous females and viviparous females form only a tiny part of her progeny. The fundatrix of A. svalbardicum also produces males; however, it remains unknown whether this is the case in Aphis polaris, or if males of this species can be born only by viviparous females of the second generation.
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Number of marginal tubercles on abdominal segments 0–6 1–5 1 0–5
II–VI (0.0–5.0) (2.0–4.0) (1.0–5.0)
Se- on head occi- length 15–38 20–28 23–25 20–25
tae pital (20–25) (23) (23)
length / articular diameter 0.80–1.38 0.89–1.22 1.13–1.29 0.89–1.25 of 3rd antennal segment (0.94–1.23) (0.89–1.19) (0.89–1.18) frontal length 25–48 25–38 30–33 25–43 (29–39) (29) (25–43) length / articular diameter 1.22–2.38 1.10–1.67 1.50–1.71 1.11–1.89 of 3rd antennal segment (1.33–1.77) (1.11–1.62) (1.11–1.89)
on 3rd number 3–9 6–10 8–9 5–8
antennal (4.0–7.6) (7.0–10.0) (5.7–7.0)
segment length 18–25 15–25 18–20 18–25
(19–25) (18–24) (22) length / articular diameter of 3rd 0.83–1.43 0.67–1.11 0.88–1.00 0.88–1.25 antennal segment (0.89–1.20) (0.73–1.03) (0.88–1.18) longest dorsal / mid-diameter of the 0.75–1.33 0.86–1.06 0.94–1.13 0.80–1.11 hind tibia (0.84–1.09) (0.87–1.00) (0.84–1.11)
on dorsal length 18–25 20–24 18–25 18–25
ab- (20–25) (22) (21)
do- length / articular diameter of 3rd 0.78–1.43 0.85–1.06 0.88–1.25 0.88–1.18
mi- antennal segment (0.89–1.16) (0.95–1.03) (0.88–1.18)
nal mar- length 18–35 20–38 25–30 23–30
ter- ginal (26–35) (25–38) (24–30)
gite
III length / articular diameter of 3rd 0.93–1.86 1.00–1.67 1.25–1.50 1.11–1.41 antennal segment (1.20–1.65) (1.13–1.58) (1.11–1.41) ven- length 30–53 30–41 35–38 28–43
tral (33–41) (32–41) (33–39)
length / articular diameter of 3rd 1.44–2.63 1.30–1.78 1.72–2.14 1.38–2.13 antennal segment (1.44–2.02) (1.44–1.73) (1.56–1.88) ......continued on the next page
Last antennal length of base 106–132 111–139 116–134 116–129
segment (114–126) (118–126) (121)
length of processus terminalis 111–152 164–192 195–218 101–185 (119–150) (164–190) (154–172) length of processsus terminalis / 0.94–1.33 1.36–1.50 1.51–1.87 0.87–1.52 length of base (0.94–1.25) (1.44) (1.25–1.40)
Ultimate number of accessory setae 2–3 1–2 2 2
rostral segment (2.0–2.5) (1.8)
length 109–132 116–126 119 109–121 (117–128) (120) (115) length / head width across the 0.24–0.29 0.25–0.28 0.27–0.28 0.25–0.28 compound eyes (0.24–0.27) (0.27) (0.26) length of 2nd segment of 1.02–1.27 1.02–1.24 1.02–1.04 1.01–1.15 hind tarsus (1.07–1.17) (1.05–1.13) (1.07) length of base of last 0.93–1.16 0.87–1.07 0.89–1.02 0.88–1.04 antennal segment (0.94–1.10) (0.94–1.00) (0.95)
Second length 96–116 96–119 114–116 101–113
segment of (103–114) (110) (107)
hind tarsus length / head width across the 0.22–0.25 0.23–0.27 0.27 0.24–0.25 compound eyes (0.22–0.24) (0.25) (0.24) Systematic relationships. There are 13 species of the genus Aphis living on Astragalus (Blackman & Eastop, 2014; Holman, 2009)— Aphis astragali Ossiannilsson, 1959, A. astragalicola Holman & Szelegiewicz, 1971, A astragalina Hille Ris Lambers, 1974, A. ciceri F. P. Müller, 1986, A. craccae Linnaeus, 1758, A. craccivora Koch, 1854, A. cytisorum Hartig, 1841, A. fabae Scopoli, 1763, A. gallowayi Robinson, 1991, A. gossypii Glover, 1877, A. loti Kaltenbach, 1862, A. masoni Richards, 1963, A. tacita Huculak, 1968, and 7 species of the genus Aphis living on Oxytropis—A. oxytropis Pashtshenko, 1993, A. oxytropiradicis Pashtshenko, 1993 and aforementioned A. astragali Ossiannilsson, 1959, A. craccae Linnaeus, 1758, A. craccivora Koch, 1854, A. fabae Scopoli, 1763, and A. masoni Richards, 1963. Aphis cytisorum and A. loti were found on Astragalus only once and probably were on it accidentally. The differences between apterous viviparous females of all these species and those of Aphis polaris sp. n. are detailed in Table 3.
Note. The signs and indices which distinguish Aphis polaris from other species most distinctly are marked out by clarendon.
In addition, A. astragalicola, A. ciceri, and A. oxytropiradicis have well-developed, dome-like marginal tubercles on all abdominal tergites II–IV, whereas marginal tubercles are only sporadically present on abdominal tergites II–IV of A. polaris. Apterous viviparous females of A. gallowayi have secondary rhinaria on the third antennal segment, whereas they are absent in A. polaris. Aphis fabae and A. tacita have only a short transverse band on abdominal tergite VIII, which is not extended lateroventrally. Aphis polaris has a transverse band that extends lateroventrally, encircling the segment almost to the subgenital plate. The dorsal abdomen of A. oxytropiradicis is devoid of any sclerotization, whereas A. polaris has transverse bands on all abdominal tergites.
The new species is most similar to A. craccae and A. astragali. Both latter species are characterized by a different type of sclerotization: abdominal tergites I–III are much less sclerotized compared to tergites IV–VI, where bands often form a single patch. If these anterior abdominal tergites are merged in A. craccae, usually a solid inverted T-shaped patch is visible. In contrast, in all apterous morphs of A. polaris, the increase in the degree of sclerotization from the first to the last abdominal tergites is gradual, exhibiting no abrupt transitions. Aphis craccae is also characterized by a greater length of the processus terminalis in relation to that of the base of the last antennal segment (Table 3) and by a greater absolute length of the second segment of the hind tarsus—148–162 Μm (Heie, 1986; Stroyan, 1984) (96–119 Μm in A. polaris). Aphis polaris differs from A. astragali by a different caudal shape and length: the cauda of the apterous viviparous female of A. astragali is long (230–325 µm), elongate tongueshape, nearly parallel-sided (Heie, 1986; Heikinheimo, 1984; Ossiannilsson, 1959), whereas the cauda of the apterous viviparous female of A. polaris is relatively short (162–210 µm), elongated-triangular. The cauda of the alate viviparous females and oviparous females of A. astragali (fundatrices of Aphis astragali are unknown) also is long (250 and 180–230 µm, respectively) and tongue-shaped (Heikinheimo, 1984); the cauda of alate viviparous females and oviparous females of A. polaris is short (142–157 and 142–177 µm, respectively) and elongatedtriangular as in apterous viviparous females.
description: Published as part of Stekolshchikov, Andrey V. & Khruleva, Olga A., 2014, A contribution to the aphid fauna (Hemiptera: Aphididae) of Wrangel Island, pp. 298-320 in Zootaxa 3887 (3) on pages 304-312, DOI: 10.11646/zootaxa.3887.3.2, http://zenodo.org/record/225982