Diagnosis. A. pistaciae is very similar to A. minimella, male differs by the absence of a central yellow spot on the forewing underside and absence of costal bristles; also the hairpencil is more distinct in pistaciae. Male genitalia characterized by medial toothed lobe of valva in contrast to the basal lobe in minimella, and by the U-shaped ventral process; the female genitalia are distinguished by the elaborate vaginal sclerotisation with three processes and the 2½ convolutions in the ductus spermathecae (3 in minimella).
Description. Male. Forewing length 1.8–2.4 mm, wingspan 4.0–5.3 mm. Frontal tuft ochreous white to yellowish white, occasionally with few fuscous scales. Scape white, antenna with 27–33 segments. Thorax and forewing ochreous, irrorate with few light brown scales, cilia white, cilia line indistinct; underside without yellow spot; basalmost dorsal cilia forming long hairpencil. Hindwing grey, costal bristles absent; distinct, yellowish brown hairpencil arising near frenulum; mixing with forewing hairpencil; underside yellow basally. Abdomen yellow with darker middorsal line; anal tufts grey.
Female. Forewing length 1.6–2.2 mm, wingspan 3.7–4.9 mm. Antenna with 20–30 segments. Hairpencils absent. Abdomen dorsally brown, abdominal tip broadly rounded.
Male genitalia. Measurements: see Table 3. Vinculum anteriorly concave, ventral plate not large. Tegumen small, triangular; uncus band-shaped, with indistinct central process, in lateral view split distally; gnathos with long narrow central element. Valva narrow, with medial inner lobe, with variably toothed margin and a smaller lobe dorsally, hidden by ventral lobe. Transtilla without transverse bar, sublateral process distinct. Aedeagus with bifurcate ventral carina or with 4–5 lobes, ventrally tightly fused to U-shaped ventral process; a pair of curved dorsal carinae present; vesica with large curved cornutus and basal sclerotisation associated with cathrema; many smaller cornuti.
Female genitalia. T8 narrow, with produced lateral corners, two small groups of scales and some setae. Anal papillae conspicuous, with 15–20 setae; apophyses straight, of approximately same length. Total length of bursa ca. 530–760 μm. Vestibulum with elaborate sclerotisations, more or less forming ring and three apophyses, partly serrate. Ductus bursae with many pectinations; corpus bursae without pectinations; with reticulate signa, shortest ca. 285–325 μm, longest 310–420 μm long, margin crenate and narrow, 2–3 cells wide. Ductus spermathecae with 2½ convolutions.
Final instar larva. Head capsule ca. 315–380 μm wide. Mandibular cusps blunt. A9 with 3 pairs of setae. Integument covered with extremely short microtrichia (ca 1μm long) on all segments. No obvious differences with A. minimella.
Host plants: Pistacia terebinthus and P. lentiscus (Anacardiaceae), frequently found on both hosts.
Egg on leaf upperside, usually close to a vein. Leafmine on P. lentiscus indistinguishable from that of minimella, starting as an extremely narrow gallery filled with frass; the thin part is more than half the total length of the mine; later, mine widening gradually and becoming more contorted, less often in a zigzag course than minimella, with blackish or brownish frass coiled or in loose pellets filling about two thirds of mine width; exit hole on leaf upperside. Mines in the thinner leaves of P. terebinthus a narrow gallery throughout, gradually widening, frass leaving clear margins, occasionally frass line becoming wider. The mine on both hosts may be confused with that of Simplimorpha promissa; see under A. minimella.
Eastern Mediterranean region: Widespread in Greece, including its islands, and in Cyprus and Turkey. To be expected in Syria and Lebanon. Mines collected in Israel by Amsel & Hering (1931) and identified as Simplimorpha promissa (Staudinger) are tentatively regarded to be this species, although no adults were seen. The distribution of A. pistaciae is apparently completely vicariant with that of A. minimella, the contact zone (if any) may be found between Montenegro and northern Greece.
This taxonomic description is based on Van Nieukerken (2007).