Acyrthosiphon pilosum Nieto Nafría, Aldea & Castro, 2015

Nieto Nafría, Juan M., Aldea, Marta & Castro, Marta, 2015, A new species of Acyrthosiphon (Hemiptera, Aphididae) from France and Spain, Zootaxa 3919 (2), pp. 335-342 : 335-340

Acyrthosiphon pilosum Nieto Nafría, Aldea & Castro , sp. n.

Diagnosis. Aphids 2.1–3.8 mm long; green when alive; brownish yellow when mounted. First segment of tarsi with 5 setae (infrequently 4 or 3); ultimate rostral segment with 19–36 accessory setae, and longer than second segment of hind tarsus; marginal tubercles present on prothorax and several abdominal presiphuncular segments; antennal and dorsal abdominal setae at least 0.4 times the basal width of antennal segment III; antennal segment III with 3–11 secondary sensoria (exceptionally up to 22) on its proximal half in apterous viviparae and 12–30 along length of segment in alate viviparae.

Description. Apterous viviparous females ( Figure 1 ), described from 166 specimens, of which 117 have been measured. Shiny green when alive. Brownish yellow in general (see details below) when mounted ( Figure 1 A). Metric and meristic features in Table 1. Head (including clypeus, labrum and mandibular and maxillar laminae) brownish. Frons with prominent lateral tubercles (approximately 0.5 times length of antennal segment I), wide frontal sinus and small and flat medial tubercle. Dorsum of head smooth. Antennal segments I–III usually as pale as head (darker in pigmented specimens); segments I and II smooth, proximal part of segment III with small spinules, remaining length of this segment imbricated ( Figure 1 B); segments IV–VI also imbricated, darker than the previous ones, especially in pigmented specimens. Secondary sensoria round and flat, ventrally aligned on proximal third to half of segment III ( Figure 1 B). Cephalic dorsal and antennal setae stiff and with diffuse apices. Rostrum reaching hind coxae and darkening to apex. Last rostral segment provided with many accessory setae, which are long and slightly curved ( Figure 1 C); ultimate rostral segment elongate wedge shaped. Dorsum of thorax and abdomen in general paler than dorsum of head and more-or-less wrinkled. Legs mostly pale like abdominal dorsum, tarsi and apices of tibiae pale brown ( Figure 1 A). First segments of tarsi usually with 5 setae ( Figure 1 D), but the eight specimens of one sample—from Le Casset—have 3 or 4 setae. Prothorax and several of abdominal segments 2–5 with marginal tubercles that are unusually large for an Acyrthosiphon species ( Figure 1 E). Spinal tubercles absent on head and abdomen. Thoracic and abdominal dorsal setae similar in shape to cephalic ones. Intersegmental and spiracular sclerites usually inconspicuous ( Figure 1 A), only evident in darkest specimens. Marginal areas of abdominal segment 6 (postsiphuncular), and transverse bands of segments 7 and 8 with spinules. Siphunculi pale, very variable in length, even in specimens from the same sample, subcylindrical, with enlarged base, thin but sometimes slightly swollen on the distal third, scabrous or imbricated over their entire length, and with subapical incision (with 1-3 transversal lines) and flange ( Figure 1 F). Cauda pale or dusky, broad triangular, with obtuse apex; caudal setae thick and slightly curved ( Figure 1 G). Subgenital plate also pale, and anal plate pale or dusky ( Figure 1 A).

apt.viv.fem. al.viv.fem. ov.fem.

Body [mm] 2.400–3.725 2.125–3.525 2.400–2.600 Antenna [mm] 2.260–3.360 2.530–3.300 2.610–2.620 Antenna / Body [times] 0.80–1.22 0.85–1.19 1.00–1.01 Antennal segment III [mm] 0.56–0.88 0.60–0.81 0.52–0.64 Antennal segment IV [mm] 0.38–0.66 0.42–0.65 0.35–0.43 Antennal segment V [mm] 0.29–0.47 0.36–0.49 0.30–0.36 Antennal segment VI base [mm] 0.10–0.19 0.13–0.18 0.12–0.14 Antennal segment VI processus terminalis [mm] 0.65–1.06 0.80–1.05 0.71–0.85 Antennal segment VI processus terminalis / Ant. segm. III [times] 1.03–1.44 1.09–1.48 1.28–1.37 Antennal segment VI: processus terminalis / base [times] 4.65–7.00 5.11–6.71 5.86–6.07 Secondary sensoria on Ant. segment III [number] 3–11(22) 12–30 2–5

Ultimate rostral segment [mm] 0.15–0.24 0.18–0.23 0.18–0.19 Ultimate rostral segment / its basal basal width [times] 2.05–4.00 2.22–3.64 2.53–2.53 Ultimate rostral segment / hind tarsus 2nd segment [times] 1.00–1.62 1.06–1.68 1.31–1.46 Hind femur [mm] 0.80–1.28 0.85–1.23 0.78–0.85 Hind tibia [mm] 1.42–2.30 1.60–2.30 1.42–1.60 Scent plates (pseudosensoria) —– —– 102–125 Hind tarsus 2nd segment [mm] 0.13–0.18 0.13–0.17 0.13–0.15 Abdominal (segment 2-5) marginal tubercles [number on one side] 3–4 3–4 4

Siphunculus [mm] 0.52–1.09 0.62–0.88 0.60–0.65 Body / Siphunculus [times] 2.91–5.18 3.43–4.86 3.93–4.06 Siphunculus / head diameter [times] 1.30–2.31 1.44–2.02 1.50–1.67 Siphunculus / Ant. segment III [times] 0.87–1.37 0.89–1.24 1.00–1.17 Siphunculus / its basal width [times] 4.27–7.54 4.47–8.86 4.57–5.55 Siphunculus / its middle width [times] 8.83–19.60 10.83–15.40 10.00–10.83 Siphunculus / Cauda [times] 1.63–2.50 1.74–2.48 2.21–2.26 Cauda [mm] 0.30–0.47 0.25–0.43 0.27–0.29 Cauda / its basal width [times] 1.50–2.37 1.68–2.77 1.80–1.81 Setae on …

… antennal segment I [number] 4–15 5–12 7–8

… antennal segment II [number] 3–9 4–11 5–6

… antennal segment III [number] 15–37 20–34 17–22

......continued on the next page apt.viv.fem. al.viv.fem. ov.fem. … antennal segment III [µm] 15.0–42.5 17.5–27.5 25.0–25.0 … antennal segment III / basal width ant. segment III [times] 0.4–1.1 0.5–0.9 0.6–0.7 … vertex [µm] 32.5–55.0 32.5–50.0 37.5–50.0 … vertex / basal width ant. segment III [times] 0.9–1.8 1.0–1.5 1.1–1.3 … ultimate rostral segment [number] 19–36 21–30 23–28 … hind femur, ventral [µm] 15.0–40.0 20.0–30.0 20.0–35.0 … hind femur dorsal / basal width ant. segment III [times] 0.5–1.3 0.5–0.8 0.6–1.0 … hind femur ventral / basal width ant. segment III [times] 0.4–1.3 0.5–0.9 0.6–0.9 … hind tibia, dorsal [µm] 20.0–42.5 23–35 27.5–35.0 … hind tibia / tibial diameter (at middle) [times] 0.4–1.0 0.5–0.8 0.5–0.6 … abdominal segment 3 [number] 8–16 8–14 10 … abdominal segment 3 [µm] 20.0–50.0 25.0–40.0 27.5–40.0 … abdominal segment 3 / basal width ant. segment III [times] 0.5–1.7 0.7–1.3 0.8–1.1 … abdominal segment 7 [number] 5–14 6–14 7–9 … abdominal segment 8 [number] 4–9 4–8 6–8 … abdominal segment 8 [µm] 32.5–65.0 32.5–52.5 45.0–57.5 … abdominal segment 8 / basal width ant. segment III [times] 0.8–1.9 0.9–1.9 1.3–1.5 … cauda [number] 7–15 9–12 12 –14 … genital plate, discal [number] 4–25 8–16 14–16 … genital plate, marginal [number] 8–23 13–20 16–17 Alate viviparous females ( Figures 2 A–B) described from 37 specimens, 27 of which have been measured. Colour when alive unknown. Head brown with areas around ocelli darker; other parts of head pigmented as in aptera; prothorax pale brown; pterothorax brown with darker spots; marginal abdominal and postsiphuncular sclerites conspicuous but sometimes completely pale, with spinules; transverse sclerites on abdominal segments 7 and 8 also pale or tenuously smoky, and also with spinules; antennae; legs and sometimes siphunculi more intensely and extensively pigmented than in aptera ( Fig. 2 A). Secondary sensoria more-or-less in a line over entire length of segment ( Figure 2 B). Other qualitative features like those in aptera. Meristic and metric characters in Table 1.

Oviparous females ( Figures 2 C–D), described from 3 specimens, all of them measured. Colour when alive unknown. Metric and meristic features in Table 1. Mounted specimens similar in shape and pigmentation to apterous viviparous females, but they have antennae and legs more extensively pigmented, spiracular and intersegmental sclerites always conspicuous and pigmented, siphunculi brown, and genital plate with two symmetric dusky spots ( Figure 2 C). Tibiae of hind legs slightly enlarged on the proximal half, with round and small scent plates on proximal three-quarters of their length ( Figure 2 D).

Biology. Acyrthosiphon pilosum sp. nov. lives on O. natrix , also on O. ramosissima , O. spinosa and possibly on other species of Ononis . Oviparous females were collected at two locations in southern France in mid-October, indicating that this species is holocyclic and monoecious, like other species of the genus.

Distribution. The type specimens were collected in three localities of southern Spain and in eight localities of south-eastern France. It could be assumed that this species also lives in areas of the Mediterranean coastal strip of Spain and France, but it must be very rare, since it has never been collected in the eastern Spanish provinces of Castellon, Valencia and Alicante, which have been intensively sampled by several authors. The known altitudinal range of the species is wide, from the sea level to 1700 m.

Types. Holotype: viviparous apterous female, FRANCE: Hautes-Alpes: Guillestre à Ceillac (1400 m), 23.VIII.1987, on O. natrix ; G. Remaudière leg.; collection of the Muséum national d’Histoire naturelle (Paris, France), sample 15425, measured specimen number 17. Paratypes: 65 viviparous apterous females and 6 alate females belonging to the same sample that the holotype; 66 apterous viviparous females, 27 alate viviparous females, FRANCE: Alpes-Maritimes: Coursegoules (640 m), 24.VI.1990, on O. natrix ; 1 apterous viviparous female, FRANCE: Hautes-Alpes: Guillestre à Ceillac (1400 m), 23.VIII.1987, on O. spinosa ; 1 oviparous female, FRANCE: Hautes-Alpes: La Grave (1520 m), 19.X.1986, on O. natrix ; 8 apterous viviparous females, FRANCE: Hautes-Alpes: Le Casset (1600 m), 9.VIII.1965, on O. sp.; 4 apterous viviparous females, 2 oviparous females, FRANCE: Hautes-Alpes: Risoul (1700 m), 16.X.1986, on O. natrix ; 8 apterous viviparous females, 4 alate viviparous females, FRANCE: Hautes-Alpes: Vars, nord (1550 m), 26.VII.1969, on O. natrix ; 1 apterous viviparous female, FRANCE: Hautes-Alpes: Villeneuve-la-Salle (1400 m), 19.VIII.1987, on O. natrix ; 4 apterous viviparous, SPAIN: Almería: El Alquián (5 m), 24.V.1980, on Ononis sp.; 2 apterous viviparous, SPAIN: Cádiz: Alcalá de los Gazules (170 m), 12.VI.1984, on Ononis ramosissima ; 6 apterous viviparous females, SPAIN: Granada: Lanjarón (660 m), 28.VI.1984, on O. natrix ; French specimens collected by G. Remaudière, and Spanish ones collected by Mier Durante & Nieto Nafría Muséum national d’Histoire naturelle (Paris, France) and Universidad de León (Leon, Spain) collections.

Etymology. The specific epithet of the new species, pilosum , is a Latin adjective in nominative singular and neutral gender, which means “hairy” and refers to the high number of setae that these aphids have on the first tarsal segments and on the distal segments of the rostrum.

Figures

FIGURE 1. Acyrthosiphon pilosum sp. n., apterous viviparous female: A, habitus; B, antenna, proximal; C, rostrum, distal; D, marginal zone of abdominal segment 1 – 5, with marginal tubercles; E, end of tibia and tarsus (in part) of a hind leg; F, siphunculus; G, cauda, and anal and genital (in part) plates.

FIGURE 2. Acyrthosiphon pilosum sp. n., A – B, alate viviparous female, C – D, oviparous female: A, C, habitus; B, III antennal segment; D, hind tibia.