Linguisaccus, Han & Galsworthy & Xue, 2012

Han, Hongxiang, Galsworthy, Anthony C. & Xue, Dayong, 2012, The Comibaenini of China (Geometridae: Geometrinae), with a review of the tribe, Zoological Journal of the Linnean Society 165 (4), pp. 723-772 : 761

LINGUISACCUS GEN. NOV.

Type species: Comostolodes subhyalina Warren, 1899

Description

Adults: Antenna in male basally bipectinate, terminally filiform, filiform in female. Frons moderately protruding. Labial palpus elongate in female. Hind tibia in male dilated, with hair-pencil and terminal extension.

Wing shape and pattern. Wings green. Forewing a narrow white band along costal area, bordered externally and internally purple-red, extending inwards at one-third and two-thirds; marginal area similarly bordered, appearing as linked bead-like white patches, larger on tornal angle and sometimes on M 3, the other patches being approximately of equal size; another three white spots ringed with purplish red present respectively on the middle of M 3, the base of CuA 2 (quite small) and the middle of the inner margin. Hindwing with outer margin area similar to forewing, and the middle of the inner margin with a long and narrow purplish-red streak. Brown discal spots on both wings small. Underside much paler, dull whitish green; forewing with costal area brown; streaks on upperside discernible.

The eighth segment is modified, both the tergite and sternite being concave at middle, with a pair of sclerotized lateral processes.

Male genitalia. Uncus vestigial. Socii developed, tapering. Gnathos indistinct and ring-like. Valva short, simple. Saccus developed, tongue-like. Aedeagus broader than that of Comibaena , sclerotized, coecum penis more slender than aedeagus body.

Female genitalia. Sterigma simply to complexly modified. Ductus bursae very slender or quite short. Corpus bursae large or small, very weak. Signum absent.

Diagnosis: The wing pattern of this genus is very similar to that of Chlorochromodes and Argyrocosma . However, the male genitalia of Linguisaccus are quite different from those two genera in having a simple, tongue-like, not bifid saccus, and in the simple valva lacking any decoration.

Distribution: China, India, Nepal, Pakistan.

Etymology: The generic name, which is masculine, derives from the Latin words meaning tongue and saccus.

Remarks: Han & Xue (2011) reported that the distinct characters of the species known then as Comibaena subhyalina might justify the erection of a new genus. We now formalize this proposition.

As explained in the Introduction, Linguisaccus has a differently shaped saccus in the male genitalia from other members of the Comibaenini , and thus lacks the principal synapomorphy of the tribe. However, its wing pattern is almost identical to that of Chlorochromodes and Argyrocosma , and it shares a simple valva with Thetidia and some species of Comibaena and Protuliocnemis . It does not fit in any other tribe of the Geometrinae . Although the position is not entirely satisfactory, we consider that for the moment it is best retained within the Comibaenini .