Nigritergaphis, Zhang, Bin, Lou, Ya-Meng & Qiao, Ge-Xia, 2013

Zhang, Bin, Lou, Ya-Meng & Qiao, Ge-Xia, 2013, A new genus and species of Macrosiphini (Hemiptera, Aphididae) from China, living on Isodon eriocalyx, ZooKeys 359, pp. 1-12 : 2-3

Nigritergaphis gen. n.

Type-species.

Nigritergaphis crassisetosa sp. n.

Etymology.

The generic name, Nigritergaphis is feminine in gender and derived from the Latin words terms “nigr-” (=shining black), and “terg-” (=dorsum or back) combined with “aphis” (=plant louse).

Generic diagnosis.

In apterae: Body elliptical, of medium size. Median frontal tubercle poorly developed, antennal tubercles developed, diverging, slightly higher than median frontal tubercle, so that frons is shallowly “W” -shaped. Tergum smooth and sclerotic. Dorsal setae of body numerous, long, thick, stiff, and arising from tuberculate bases; ventral setae very sparse. Ultimate rostral segment longer than second hind tarsal segment, with 2-3 pairs of accessory setae. Eyes with relatively few facets. Antennae 5- or 6-segmented, much shorter than body, without secondary rhinaria; processus terminalis about 2-3 times longer than base of the last segment. Mesosternal furca with a short stem or separate arms. First tarsal chaetotaxy 2, 2, 2. Spiracles small, oval or reniform, open; spiracular plates oval. Marginal tubercles absent. Siphunculi short and tapering, slightly swollen towards base, with distinct imbrication and a well-developed flange, and sometimes with one seta. Cauda helmet-shaped, but slightly acute at apex, with 4 setae. Genital plate with 2 anterior setae and 10-12 posterior setae. In alatae: Abdominal tergites each with one pair of marginal patches and an imperfect spino-pleural dark band. Antennae 6-segmented, segments III–V with large and round secondary rhinaria. Fore wing median vein with two-forks, hind wing with two obliques, all veins without fuscous borders.

Taxonomic notes.

Nigritergaphis belongs to the tribe Macrosiphini of the family Aphididae , but has a unique combination of features justifying the erection of a new genus. Compared with other aphid genera associated with Lamiaceae , it differs by having numerous, thick long and stiff dorsal setae arising from tuberculate bases, and first tarsal chaetotaxy: 2, 2, 2. It is similar to Roepkea Hille Ris Lambers in the shape of the cauda, dorsal ornamentation and lack of marginal tubercles, but differs from that genus as follows: siphunculi only with weak imbrications (in Roepkea : ornamented with transverse rows of small spicules); body dorsum completely sclerotic and smooth (in Roepkea : usually dark, sclerotic, but with pale patches on the marginal areas, and with numerous small spicules). The new genus resembles Brachycaudus van der Goot in the shape of cauda, and in dorsal sclerotization, but may be distinguished from that genus by the following: lack of marginal abdominal tubercles (in Brachycaudus these are frequently present on several body segments); spiracular pores oval or reniform (in Brachycaudus they are circular and large); siphunculi imbricated and without a sharply limited subapical constriction (in Brachycaudus rather smooth, and with a sharply limited constriction below the flange). The new genus resembles Dysaphis Börner in the shape of spiracular pores and the shape of the cauda, but differs from Dysaphis as follows: abdomen of apterae with a complete sclerotic shield (in Dysaphis dorsal sclerotization never forms a complete shield); without spinal and marginal tubercles (in Dysaphis spinal and marginal tubercles are characteristically present).