Dracontogena Diakonoff, 1970

Aarvik, Leif, Karisch, Timm & Marthinsen, Gunnhild, 2012, Review of the Afrotropical genus Dracontogena Diakonoff, 1970 (Lepidoptera, Tortricidae) with descriptions of eight new species, Zootaxa 3478, pp. 345-372 : 347

Genus Dracontogena Diakonoff, 1970

Dracontogena Diakonoff, 1970: 122 . Type species: Dracontogena niphadonta Diakonoff, 1970 .

Diagnosis

The forewing pattern of Dracontogena with the two white marks on dorsum is characteristic. The only other African tortricid genus having this trait is Multiquaestia Karisch, 2005 . Males of the latter genus can easily be distinguished by the presence of a hair-pencil extending from the hind margin of the hind wing and inserted into an area of raised scales on the dorsal side of the abdomen ( Aarvik & Karisch 2009). In some species of Dracontogena the characteristic forewing white markings are partially obscured by the presence of dark suffusion. In other species the two white maculae are interconnected by a broad white band, but in most cases they are narrowly connected along the dorsal edge. In the male genitalia Multiquaestia differs from Dracontogena by the much narrower “neck” of valva, the small cucullus, and the absence of a large cornutus in the phallus. Females of Multiquaestia have the anterior edge of sternite 7 strongly sclerotised. Comprehensive descriptions of Dracontogena were given by Diakonoff (1970) and Karisch (2005).

Subdivison of Dracontogena

Karisch (2005) divided Dracontogena into two species groups, viz., the D. niphadonta group and the D. metamorphica group. This subdivision was based on characters of the male genitalia and secondary sexual characters of the male hindwing. In the present work we modify the concept of the niphadonta -species group by including all species that posses secondary sexual characters in the male. These characters are absent in the metamorphica -group. In the hindwing the following modifications may be present: 1) concavity of termen by vein CuA2; 2) black sex scales forming distinct patch on upperside distally by cell; 3) upperside basal scales narrowed; 4) fringe reduced along termen above concavity; and 5) rhopaloid scales at anal corner of hindwing. In all species of the group, abdominal segment 8 of the male has coremata consisting of a pair of lateral tufts containing long filiform scales. Inside the valva there is a circular field of large scales. The external surface of the valva has a circular opening at the centre of the scale ring. The abdominal coremata and valva scale ring are present in all known species of the group. None of these modifications are present in the metamorphica -group. The proposed subdivision of the genus is supported by the DNA-sequence data ( Fig. 78 ).

According to the male genitalia, members of the niphadonta -group can be further divided into three subgroups, one containing D. niphadonta Diakonoff, D. continentalis Karisch , D. agassizi n. sp., D. rubondoensis n. sp. D. bjornstadi n. sp. and D. angolensis n. sp. These six species have a relatively long and slender phallus, and the cucullus is only weakly demarcated from the rest of the valva. The two species D. bernardi Karisch and D. solii n. sp. form a second subgroup, sharing a short, bottle-shaped phallus and an incision on the dorsal edge of the valva which forms a distinct demarcation of the cucullus. Dracontogena tonitrualis (Meyrick) has an isolated position due to its remarkably bent and slender valva. It is noteworthy that among closely related pairs, secondary sexual characters of the male hindwing may be present in one and absent in the other. Examples of this are found in D. continentalis Karisch and D. agassizi n. sp. and the pair D. bernardi Karisch and D. solii n. sp. In the latter case no differences in the genitalia were detected. The male genitalia of the species in the metamorphica -group are rather uniform. Only D. deltozyga (Meyrick) differs strongly from the other species due to its very broad cucullus.

Systematic position

The genus belongs to the Grapholita genus group sensu Komai (1999) which is a part of the tribe Grapholitini . In the male genitalia the ventral margin of the sacculus is nearly straight, not strongly convex as in the Cydia genus group. The tegumen is strongly curved at the base. There are pencils of coremata laterally on abdominal segment 8 in males (absent in metamorphica -group), and a scale brush on the male hind tibia. The female corpus bursae has a diverticulum, a synapomorphy for the Cydia genus group + Grapholita genus group. The sister genus is likely Thaumatotibia Zacher, 1915 . The male genitalia, sternum 8, tergite 8, and pencils of coremata ( Fig. 1 ) are essentially the same among the two genera (see figures of the type species, T. leucotreta (Meyrick, 1913) in Komai 1999: figs. 63, 64). The rhopaloid scales, which are situated at the anal corner of the hindwing, are present in Thaumatotibia leucotreta and members of the Dracontogena niphadonta species group. They have not been found in other genera of Grapholitini that we have examined. Karisch (2005) compared additional characters of the genitalia in both sexes with those of Thaumatotibia and Cryptophlebia Walsingham, 1899 .

Figures

FIGURE 1. Pregenital structures in male abdomen in Dracontogena solii n. sp. (slide NHMO 2010). Scale 3 mm.

FIGURE 78. Neighbour-joining tree based on COI sequences. The Kimura- 2 substitution model is applied. Numbers at nodes indicate bootstrap support based on 1000 replications. The Thaumatotibia leucotreta sequence used as outgroup is taken from Genbank, accession number is given.