Aphis oxalicola, Stekolshchikov, 2024

Stekolshchikov, Andrey V., 2024, A contribution to the aphid fauna (Homoptera, Aphidinea) of the Republic of Dagestan (the Russian Federation), with descriptions of three new species, redescription of Macrosiphum pulcherimum Nevsky, 1928, and descriptions of previously unknown morphs of three species, Zootaxa 5545 (1), pp. 1-68 : 40-42

Aphis oxalicola sp. nov.

( Figs 78–87 , Table 7)

Type material. Holotype: apterous viviparous female, No. 11900, slide No. 6, “ Aphis oxalicola sp. nov., 19.ix.2023, Republic of Dagestan, Magaramkentsky District, National Park “Samursky”, sector “Samur River delta”, nearby Bilbil-Kazmalyar Vill., Oxalis stricta L., on the base of leaf petioles, leg. A. V. Stekolshchikov”. Paratypes: 15 apterous viviparous females, same data as holotype.

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Etymology. The specific name “ oxalicola ” is an adjective in feminine gramatical gender derived from the genus name of host plant ( Oxalis ) and the Latin suffix “-cola” (from cŏlo meaning to inhabit).

Description. Apterous viviparous female. Body broadly elliptical, 1.5–1.9 (1.7) times as long as wide. Living specimens dark gray green, dull shiny or matte above, matte below; apices of antennae, hind femora, apices of tibiae, tarsi, siphunculi and cauda dark. Cleared specimens with frons, siphunculi and cauda dark brown; with head (except frons), 1st and 2nd antennal segments, two last segments of rostrum, sclerites in base of coxae, coxae, trochanters, middle and hind femora (except base), apices of tibiae and tarsi of all legs, and sclerites and bands on all segments of thorax and abdomen, peritremes on abdominal segments, anal and subgenital plate brown; with 3rd–6th antennal segments, fore femora and all tibia (except apices) light-brown. Degree of sclerotization of individuals varies from strong, with wide sclerotized bands and large marginal sclerites on all thoracic tergites, bands on abdominal tergites I – VI and marginal sclerites on abdominal segments II – V fused into a single carapace and distinct bands on abdominal segments VII – VIII, to middle, when bands on thoracic tergites divided into separate sclerites, and band on metanotum sometimes almost completely disappears, band on Ist abdominal segment also divided into separate sclerites, marginal sclerites on abdominal segments absent, bands on tergites II – VI fuse only partially and carapace strongly fragmented, with many transparent “windows”, and bands on tergites VII – VIII are thin, poorly visible and often completely disappear. Surface of head, dorsal side of thorax, abdominal tergites I–VII reticulate; contour of cells on thorax and abdominal tergites I–VI formed by wide irregular line, and on tergite VII, by flat fused large spinules. Surface of abdominal tergite VIII with long rows of small pointed spinules which partially fusing and forming scales. Surface of ventral side of thorax reticulate, contour of cells formed by small pointed spinules; the same of abdomen with long rows of small pointed spinules sometimes forming strongly stretched reticulate cells. Setae on head, antennae, dorsal and ventral sides of thorax and abdomen blunt; numbers of marginal setae 1, 1–2, 1– 2, 1–2 1–2, 1–3, 0–1 on each side of abdominal segments I–VII, respectively. Marginal tubercles always present on prothorax and abdominal segments I and VII, and often on abdominal segments II – VI, number of marginal tubercles on abdominal segments II – VI—5–9 (7.2); marginal tubercles protuberant or strongly protuberant, small tubercles up to nipple-shaped, diameter of tubercles on segments II – VI 0.8–2.8 times as long as high, 1.0 – 3.6 times as wide as width of siphunculi in the middle. Head without epicranial suture or with its weak traces. Frontal tubercles distinct but not well developed; antennal tubercles relatively high; median tubercle wide and flat, not surpassing the level of antennal tubercles. Antennae 6-segmented; 1st, 2nd and base of 3rd antennal segment slightly wrinkled, almost smooth, 3rd (except base) and 4th–6th segments with large scales.Antennae without secondary rhinaria and only one individual has 1 rhinaria on 3rd antennal segments. Rostrum reaching metathorax or abdominal segment II. Ultimate rostral segment elongate wedge-shaped, with straight or slightly concave sides, 2.00–2.56 (2.25) times as long as its basal width. Legs normally developed; setae on tarsi pointed, on tibiae blunt or pointed, on coxae, trochanters and femora blunt. Chaetotaxy of first tarsal segments 3, 3, 2. Arms of mesosternal furca connected by wide sclerotized base. Spiracles reniform. Siphunculi almost cylindrical, gradually tapering towards apex, sometimes very weak curved outward, with relatively small, but distinct flange. Surface of siphunculi imbricated, covered by rough scales which sometimes formed by partially fused large pointed spinulae. Subgenital plate oval, with pointed setae. Setae on anal plate finely pointed. Cauda finger-shaped, with distinct constriction in basal third, then almost cylindrical with rounded apex and long finely pointed setae.

Measurements of the holotype. Body—1555×910, antenna—1004: III—204×63 (in middle), IV—145, V— 149, VI—98+265; hind femur—396, hind tibia—714; siphunculus—261×47 (in middle); cauda—84×130 (at base) ×79 (before base). Additional measurements are given in Table 7.

Distribution. Known only from the type locality— Russia, Republic of Dagestan, Magaramkentsky District, National Park “Samursky”, sector “Samur River delta”, nearby Bilbil-Kazmalyar Vill.

Biology. Life cycle is unknown.A colony of this species consisted of apterous viviparous females and immatures was found on 19.ix.2023 on the base of leaf petioles of Oxalis stricta L. and were covered with soil by ants.

Systematic relationships. Aphis oxalicola sp. nov. is very close to Aphis craccivora Koch, 1854 , but differs from it in the presence of marginal tubercles on abdominal segments II–IV and VI, and also sometimes on abdominal segment V, and in the number of marginal tubercles on abdominal segments II–VI—5–9 (7.2). In Aphis craccivora Koch, 1854 , marginal tubercles on abdominal segments II–VI are rare, the number of marginal tubercles on abdominal segments II–VI is 0–3 (0.7), and only one aberrant aptera from Melilotus with 8 tubercles on abdominal tergites II–VI was observed ( Stroyan 1984).

Rusanova (1942) and Abashidze (1950) indicate that they found the species Aphis oxalina Theobald, 1925 in Azerbaijan and Georgia, respectively, which Eastop & Hille Ris Lambers (1976) consider as a synonym of Aphis craccivora Koch, 1854 . It cannot be excluded that these findings from the Caucasus do not refer to A. craccivora , which is capable of living on Oxalis , as is shown by the established fact of synonymy of A. oxalina and A. craccivora , but to the new species described here.

Figures

FIGURE 78. Apterous viviparous female of Aphis oxalicola sp. nov., habitus.

FIGURE 79. Apterous viviparous female of Aphis oxalicola sp. nov., habitus. Specimens with extreme variants of sclerotization: A. minimal; B. maximal.

FIGURES 80–87. Aphis oxalicola sp. nov., apterous viviparous female. 80, antennae; 81, 3rd antennal segment; 82, last antennal segment; 83, head; 84, III and ultimate rostral segments; 85, hind tarsus; 86, siphunculus; 87, cauda.