Pseudepisothalma Han
Creators: name: Xue, Dayong
name: Wang, Xuejian
name: Han, Hongxiang
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Geometridae
Pseudepisothalma

description: Pseudepisothalma Han gen. nov.
Type species. Episothalma ocellata Swinhoe, 1893.
Description. Head: Antenna ciliate in male. Frons with scales smooth, moderately protruding. Labial palpus short, not extending beyond frons. Thorax: Forewing with apex falcate; outer margin concave from apex to vein M3, and straight from vein M3 to anal angle; anal angle nearly quadrate. Hind wing with apex rounded, outer margin deeply concave between vein M1 and M3, forming large teeth on both veins; anal angle nearly quadrate. Venation same as that of Episothalma. Abdomen: Male genitalia (Figs. 22, 33). Uncus sclerotized, slender, tapered and pointed at tip. Socii broad, slightly sclerotized, shorter than uncus. Gnathos with median process long and pointed. Valva moderately sclerotized, terminal part with ventral half truncate, dorsal half with a strongly sclerotized, spinose process; costa forming a large sclerotized, rounded, spinose process near center; costal terminal process membranous, long and slender; ventral margin of valva concave at middle. Transtilla slightly sclerotized. Juxta sclerotized, labiate. Saccus not protruding. Coremata present. Aedeagus with terminal part sclerotized, spinose. Female genitalia unknown.
Etymology. This generic name is from the Latin pseud- and the genus Episothalma, which means not true Episothalma.
Diagnosis. The type species of this new genus Pseudepisothalma was originally placed in Episothalma, but the male genitalia are absolutely different from those of the members of that genus. For example: the gnathos of Pseudepisothalma has a developed median process, but it is absent in Episothalma; Pseudepisothalma does not have the typical hook-like structure on the valva, but has a developed process on the costal margin and a terminal process on the valva, which are absent in Episothalma. The aedeagus has many small spines on the manica in Pseudepisothalma, but has large processes or none in Episothalma. In wing pattern, Pseudepisothalma is different from Episothalma in having radial lines outside the postmedial lines on the dorsal side, a different colour and distinct straight postmedial lines on the ventral side.
The ventral side of the wings is reminiscent of that of Chlorodontopera discospilata (Moore, 1868), which is the only member of that genus with a yellow ventral side, in having a yellow background colour and straight dark postmedial lines. But the bipectinate antennae in the male immediately separates Ch. discospilata from Pseudepisothalma. Pseudepisothalma is also distinguished from Ch. discospilata by features of the male genitalia. For example, the uncus is deeply bifid and Y-shaped in Ch. discospilata, but is tapering and sticklike in Pseudepisothalma; the lateral arms of the gnathos of Ch. discospilata are separate though very long and with modification, but they are joined together in Pseudepisothalma and form a simple median process. In addition, Ch. discospilata has much larger discal spots on the dorsal side of the wings; Ch. discospilata bears two pairs of spurs in the male hind tibia, while Pseudepisothalma only has one pair of terminal spurs; sternite 3 in the male bears a pair of setal patches in Ch. discospilata, which are absent in Pseudepisothalma.
The male genitalia of the specimens on which Pseudepisothalma is based have uncus and socii reminiscent of the Hemitheini on the basis of the following characters: the socii and uncus are closely adpressed; the socii are shorter than the uncus; veins M3 and CuA1 of the hind wing are stalked. On this basis, they fall clearly within the tribe Hemitheini. But within the tribe, the male genitalia of this species are distinctive in having a very special unusual valva shape: the ventral half is truncate and a spinose process is present on the dorsal half, whereas other genera in the Hemitheini usually have blunt and rounded apices; the costal terminal process is membranous, but is usually sclerotized in the Hemitheini where it exists, for example in Culpinia diffusa (Walker). We conclude that it is not possible to fit this species convincingly into any other existing genus.
description: Published as part of Xue, Dayong, Wang, Xuejian & Han, Hongxiang, 2009, A revision of Episothalma Swinhoe, 1893, with descriptions of two new species and one new genus (Lepidoptera, Geometridae, Geometrinae), pp. 12-25 in Zootaxa 2033 on page 23, DOI: 10.5281/zenodo.186318