Aphis eucollinae López Ciruelos & Ortego, 2016

López Ciruelos, Sara I., Durante, M. Pilar Mier, Ortego, Jaime, García-Tejero, Sergio & Nieto Nafría, Juan M., 2016, Three new South American species of genus Aphis (Hemiptera: Aphididae) living on species of Euphorbia (Euphorbiaceae), Zootaxa 4085 (1), pp. 103-118 : 111-114

Aphis eucollinae López Ciruelos & Ortego , sp. n.

Types. Holotype: apterous viviparous female (measured specimen number 2 of sample ARG-137) ARGENTINA, Mendoza, Malargüe (35º 28’ S, 69º 34’ O, 1420 m), 19 April 1996, on Euphorbia collina, Ortego leg.; collection of the University of León ( León , Spain ) . Paratypes: 1 viviparous apterous female and 26 oviparous females collected at the same time as the holotype; 165 apterous viviparous females, 7 alate viviparous females, 17 oviparous females and 7 males, ARGENTINA, Mendoza, Malargüe, 5 and 21 April 1995, 29 Mars 1996 and 29 January 2003; collections of University of León, Natural History Museum , London (U.K.) and of Jaime Ortego (Mendoza, Argentina ) .

Apterous viviparous females ( Figs. 3A, 3B , 4C , 5C, 5K ), from 167 specimens, of which 49 have been measured. When alive long oval-shaped, yellow coloured sometimes with brown dorsal markings, and with appendages and siphunculi brownish to brown. When mounted generally pale with brown parts (see details below). Metric and meristic features in Table 4. Frons nearly flat. Head, including clypeus and mandibular and maxillary lames, pale brown. Antennal segments I, partially VI, and apically IV and V more or less darker than head, other parts of antennae pale or very slightly pigmented; segments I and II nearly smooth, II with sparse and small spinules on ventral face, segments IV to VI imbricated. Rostrum just reaches to the hind leg coxae, brownish, with last two segments darker; the ultimate segment carries two accessory setae. Most part of legs yellowish, only tarsi and a distal portion of tibiae brown, more-or-less pigmented like most of siphunculi and always darker than cauda. Marginal tubercles on prothorax protuberant, taller than wide. Summer specimens with a very limited dorsal sclerotization and pigmentation on thorax and abdomen, usually a narrow strip on prothorax and on abdominal segments 6 (sometimes), 7 and 8, small and brownish intersegmental sclerites and light spiracular sclerites. Autumnal specimens with individual transverse bands (sometimes fragmented) on prothorax and mesothorax, marginal sclerites on metathorax, spinal sclerites (sometimes coalescent) and very small marginal sclerites on abdominal segments 2–5, postsiphuncular and spinal (sometimes lacking) sclerites on segment 6 and individual transverse bands on 8 and 9; intersegmental sclerites dark brown, and spiracular sclerites small and yellowish. Marginal tubercles of abdominal segments 1 and 7 smaller than prothoracic tubercles. Intermediate abdominal segments usually without marginal tubercles, in several specimens one to three tubercles have been observed, always very small, nearly undetectable. Siphunculi subcylindrical or proximally tapered and distally cylindrical, imbricated, with a very small flange or without it; very pale yellow at base and progressively pigmented to dark brown at apex, which is darker than head or cauda, but always paler than tarsi. Genital and anal plates and cauda brownish. Cauda triangular. Setae of dorsum of head, thorax and abdomen relatively thick with truncated or blunt apex; other setae thinner and pointed.

Alate viviparous females ( Figs. 3C , 4F , 5F, 5N ), from 7 specimens, which 6 have been measured. When alive black (head and thorax) and yellow, with appendages brown and siphunculi brownish. In mounted specimens antennae and femora more extensively pigmented. Dark areola around each ocellus. Autumnal specimens frequently with individual spinal bands or pairs of sclerites on abdominal segments 1–4, always broad marginal sclerites on segments 2–5 and individual transverse stripes on segments 7, 8 and sometimes 6; summer specimens without spinal sclerites, and with other sclerites smaller and paler. Antennal segment III with unequal and mostly large 5–9 secondary sensoria, aligned on ventral face of segment. Other qualitative features similar to those of apterae. Metric and meristic features in Table 4.

Oviparous females ( Figs. 3D , 4G , 5G, 5O ), from 43 specimens, of which 11 have been measured. Pink coloured when alive. Similar to autumnal apterous viviparae but segments 7 and 8 without transverse pigmented stripes. Hind tibiae slightly thickened, with 51–105 scent plates, which are badly defined and very pale. Genital plate pale in the middle. Meristic and metric features in Table 4.

Males ( Figs. 3E , 4H , 5H, 5P ), from 7 specimens. Apterous, when alive darker than alate viviparous females. Qualitative features similar to those of the apterous viviparous females, but femora darker than in these females, and head and antennae darker than alate viviparous females. Antennal segment III with 12–33 secondary sensoria placed on the ventral face of distal two thirds. Metric and meristic features in Table 4.

Biology. Aphis eucollinae sp. n. lives on Euphorbia collina Phil. , which is usually considered a valid species (Missouri Botanical Garden 2015; Instituto de Botánica Darwinion 2015), although some authorities (e.g. The Plant List 2015) place it as a subspecies of E. portulacoides L. The differences observed between autumnal and summer viviparous females are frequent in species of Aphis , and are less pronounced in the studied species than in other Argentinean species, for example A. melosae and A. mendocina (see Mier Durante et al. 2006; Mier Durante & Ortego 1999). The species is monoecious and holocyclic. Eggs are laid on the stems near the ground; they are shiny yellow when fresh.

Distribution. The species is only known from Malargüe ( Argentina, Mendoza), although it may be much more widespread in the highlands where its host plant grows, as E. collina is known from many Argentinean provinces and in southern Chilean regions (Andrew W. Mellon Foundation 2015; Instituto de Botánica Darwinion 2015; Fundación Flora Chilena Darian Stark 2015).

Etymology. The specific epithet eucollinae is formed by the specific name of the host plant of this aphid in genitive singular, and the prefix eu, which means true, because these aphids were truly caught on Euphorbia collina .

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Figures

FIGURE 3. A – E, Aphis eucollinae López Ciruelos & Ortego, sp. n.; A, apterous viviparous females, habitus; B, variation of sclerotization and pigmentation; C, alate viviparous females, abdomen (dorsal view); D, oviparous female, hind tibia; E, apterous male.

FIGURE 4. Antennae. A, D, Aphis tehuelchis Nieto Nafría & López Ciruelos, sp. n.; B, E, Aphis maulensis Mier Durante & García-Tejero, sp. n.; C, F – H, Aphis eucollinae López Ciruelos & Ortego, sp. n.; A – C, apterous viviparous females; D – F, alate viviparous females; G, oviparous female; H, male.

FIGURE 5. Siphunculi and caudas. A, D, I, L, Aphis tehuelchis Nieto Nafría & López Ciruelos, sp. n.; B, E, J, M, Aphis maulensis Mier Durante & García-Tejero, sp. n.; C, F – H, K, N – P, Aphis eucollinae López Ciruelos & Ortego, sp. n.; A – C, I – K, apterous viviparous females; D – F, L – N, alate viviparous females; G, O, oviparous female; H, P, male.