Andricus guanajuatensis Pujade-Villar, 2013
Andricus guanajuatensis Pujade-Villar, In Pujade-Villar et
al. (2013b: 188)

Gall (Figs. 3f-h). Plurilocular, they develop on the branches, chestnut-red in color, large (2.0–6.0 x 1.0–5.0 cm) and regular. They are composed of smaller, hard, completely fused globular masses that surround the branches. The surface is light green when they are young and light gray at maturity, delicately rough and wrinkled; the network-shaped anastomosis have a color similar to that of the depressed areas and are often slightly cracked (this structure is visible under stereomicroscope magnification). The larval chambers (3.0 x 4.5 mm) are widely separated, not very numerous. The chamber walls are thick, yellowish, and very hard (2-3 mm thick). The galls remain on the branches for several years and become darker over time.

Hosts. Quercus obtusata and Q. rugosa (Quercus section); also mentioned on Quercus castanea Née, 1801 (Lobatae section) in the original description, but this data needs to be verified.

Biology. Species known only for the asexual generation. The adults emerge between September and May; in Santa Fe, emergences occurred in May.

Distribution. Cited in the states of Guanajuato and Queretaro (Pujade-Villar et al. 2013a); first record for Mexico City (Santa Fe) and first record on Q. rugosa.

Andricus guanajuatensis Pujade-Villar n. sp.

Gall (Fig. 14f). Galls are chestnut red, large regular, woody enlargements partially surrounding small twigs and composed by small, distinct, thoroughly fused globular masses surrounding twigs. Polythalamous, 2.0–6.0 x 1.0–5.0 cm, with hard tissue. The grey to woody coloured gall surface is delicately rough and wrinkled; the net-like anastomose are similar coloured than the depressed areas and often weakly cracked. This structure is visible under stereomicroscope magnification. The larval chambers (3.0 x 4.5 mm) are separately situated inside the gall, not very numerous. Walls of chambers are yellowish, big and very hard (2-3 mm thick). Galls remain on oak branches several years and turn darker over time.

Host.Quercus castanea Née and Q. obtusata Humb. & Bonpl. (section Quercus).

Distribution. Guanajuato and Michoacán (Mexico).

Biology. Only the asexual generation is known. Adults emerge in September and May. Gall tissues are very hard.

Etymology. Related to the State where these galls were collected.