Aphis tehuelchis López Ciruelos & Durante & Ortego & García-Tejero & Nieto Nafría 2016, sp. n.

Aphis tehuelchis Nieto Nafría & López Ciruelos, sp. n.

Types. Holotype: apterous viviparous female (measured specimen number 4 of sample ARG-111), ARGENTINA, Santa Cruz, Gobernador Gregores (48º 45´S, 70º 15’ W, 288 m), 19 January 1996, on Euphorbia sp., J. Ortego leg.; collection of the University of León (León, Spain). Paratypes: 64 viviparous apterous females, collected at the same time as the holotype; 11 apterous viviparous females, ARGENTINA, Neuquén, Lago Tromen, 23 January 2000; 7 apterous viviparous females, ARGENTINA, Neuquén, La Rinconada, 23 January 2000; 3 apterous viviparous females and 3 alate viviparous females, ARGENTINA, Neuquén, Nahuel Huapi, 14 December 2009; 50 apterous viviparous females and 2 alate viviparous females, ARGENTINA, Neuquén, Puerto Huemul, 21 January 2000; all of them collected on Euphorbia sp.; collection of the University of León (León, Spain), of Natural History Museum (London, United Kingdom) and of J. Ortego (Mendoza, Argentina).

Apterous viviparous females (Figs. 2A, 2B, 2C, 4A, 5A, 5I). From more than 500 specimens, of which 56 have been measured. When alive oval-shaped, green coloured with or without black or brown dorsal markings, partially brownish antennae and legs and dark brown to black siphunculi. When mounted, specimens are generally pale with brown parts (see details below). Metric and meristic features in Table 3. Head, including clypeus and mandibular and maxillar lames, brown. Frons nearly flat. Antennal segment I as dark as head and darker than segment II, both smooth; antennal segment III pale, dorsally smooth and ventrally spinuled; other segments imbricated; IV pale, V proximally pale and progressively darkened, VI as dark as head. Rostrum reaches to or slightly beyond the hind leg coxae; its ultimate segment is darker than the others and has two accessory setae. Most of legs pale, coxae, most of femora, apex of tibiae, and tarsi brown. Prothorax with brown transverse dorsal band, sometimes fragmented and with flat and large marginal tubercles. Both mesothorax and metathorax with a brown transverse dorsal band entire or fragmented, or only with marginal patches, all of them reticulated like other sclerotized areas of thorax and abdomen. Dorsum of abdominal segments 1–6 variably brown sclerotized: spinal sclerites present on one or several segments, entire or fragmented spinal or pleuro-spinal bands, or with a spinal or pleuro-spinal plate, usually irregularly edged and with light lines or spots. Marginal tubercles on abdominal segment 1, broad and taller than wide, bigger than those always present on abdominal segment 7; several on abdominal segments 2–6, smaller than the others but always very evident. Dorsum of abdominal segments 7 and 8 sometimes with pale brown separate sclerites or individual narrow transverse band. Intersegmental sclerites and spiracular sclerites, which are small, usually dark brown, like siphunculi. Siphunculi nearly cylindrical, with a larger small proximal portion, homogeneously dark, imbricated, with a very small flange if present. Genital plate dark with a pale medial-anterior portion. Cauda smoky and long-triangular to finger-shaped and usually longer than siphunculi. Dorsal setae on head, thorax and abdominal segments 1–6(7) truncated, other setae pointed.

Alate viviparous females (Figs. 2D, 4D, 5D, 5L), from 13 specimens. When alive similar in coloration to apterous viviparae with black head and thorax and darker appendages. In mounted specimens antennae and femora more extensively and intensively pigmented than in apterous viviparae. Antennal segment III with unequal and mostly large 4–8 secondary sensoria, aligned along segment. Abdominal segments 2–6 with marginal sclerites and individual transverse pale brown stripes on abdominal segments 6–8. Other qualitative features similar to those of apterae. Metric and meristic features in Table 3.

Aphis tehuelchis sp. n. Aphis maulensis sp. n. ......continued on the next page Aphis tehuelchis sp. n. Aphis maulensis sp. n. Biology. The type specimens of Aphis tehuelchis sp. n. were collected on an unidentified species of Euphorbia, perhaps E. schickendanttzii Hieron., E. hieronymi Subils or E. collina Phil., considering the distribution of all of these plant species provided by Subils (1977), Instituto de Botánica Darwinion (2015) and Marchessi (pers. com.). No data exists about the life cycle of the species; it should be holocyclic without host alternation, as usual in the species of this genus in the far south of America.

Distribution. Aphis tehuelchis sp. n. is known from the Argentinean provinces of Santa Cruz and Neuquén; it is reasonable to think that it also occurs in the provinces located between them (Chubut and Rio Negro) and perhaps in southern Chilean regions.

Etymology. The specific epithet tehuelchis is a Latinized noun in genitive singular, from Tehuelche, name of an indigenous people of South Patagonia.