Wednesday, June 30, 2010

Xylorycta austera

Xylorycta austera (T.P. Lucas, 1898)

Xylorycta austera, ♂ - NSW, Como West, 6. Jan. 1977, L.S. Willan V.J. Robinson leg. (LWC). [AMO].
Xylorycta austera, Don Herbison-Evans

Xyloricta austera T.P. Lucas, 1898, Descriptions of Queensland Lepidoptera. Arctiadae. Proceedings of the Royal Society of Queensland 13: 59–86 [85]. Holotype SAMA ♂, Brisbane, Qld.
Xyloricta austera, Lucas. Lucas, T.P., 1900: New Species of Queensland Lepidoptera. Proc. R. Soc. Qld. 15: 137-161 [159].
Xylorycta austera T.P. Lucas, 1898. Common, in Nielsen, Edwards, & Rangsi, 1996, Checklist of the Lepidoptera of Australia. Monographs on Australian Lepidoptera, 4: i-xiv, 1-529 & CD-ROM [89].
Xylorycta austera T.P. Lucas, 1898. Common, in Nielsen, Edwards, & Rangsi, 1996, Checklist of the Lepidoptera of Australia. Monographs on Australian Lepidoptera, 4: i-xiv, 1-529 & CD-ROM [89].
Xylorycta austera T.P. Lucas, 1898. Edwards, E. D. (2003), Xyloryctinae. Australian Faunal Directory. Australian Biological Resources Study, Canberra. [accessed 19 June 2010].

Original description, Lucas 1898
Xyloricta [sic] austera. sp. nov.
♂ mm 26. Head and  thorax creamy white. Antennae, stalk creamy white, pectinations fuscous. Palpi, creamy fuscous. Abdomen creamy white, third segment ferrous fuscous on dorsum. Forewings elongate, costa gently rounded; hind margin oblique. almost straight, creamy white, with light fuscous lines and markings; fuscous line on costa, attenuated at base; a medium fuscous line from base of wing near costa to anal angle of hind margin, suffused toward inner margin; a broader band branches from this median line at one-sixth to one-third hind margin, and a second branch at one-half extends to apex, attenuated at origin, but diffused toward costa; fuscous lines on veins in hinder half of wings; an ochreous fuscous suffusion along inner margin. Cilia creamy white, with a fuscous basal line and a median fuscous band. Hindwings creamy straw colour. Cilia white, with a straw-colour band near base. One specimen at light, Brisbane.
Subsequent description, Lucas 1900
Xyloricta [sic] austera. Lucas.
(Tr. Roy. Soc. Dec. 11, 1898.)
♂♀ 24-35 mm. As I have this year obtained better specimens of this moth, I here append a fuller description. The thorax is creamy white, with three arrow triangles of ochreous fuscous; the dorsal one is narrow, the lateral ones broader at base and bordered outwardly with fine blackish chocolate line. The segments of abdomen are creamy, shaded with ochreous along base, and a broad blotch of coppery ochreous on second segment. The forewings are cream colour, with chocolate fuscous longitudinal bifurcating bands, 1st along costa, 2nd from centre of base of wing, bifurcating at 1/6, the inner branch to anal angle of hindmargin, the other toward costa; this again bifurcates beyond middle of wing, the one branch to costa before and along apex, the other to hindmargin before middle; 3rd, a border band from near base along inner margin, thinning out to anal angle; a discoidal spot at 2/3 and touching band to hindmargin; a row of fine lines beyond and below this to hindmargin. May Orchard, Brisbane, at light, and bred.
Xylorycta austera, ♂head, gvc6451 collected by Graeme Cocks.
Xylorycta austera, ♂ antennal ciliation, K-0817, Kuranda

Antennae in the female filiform, in the male ciliated in fan-shaped fascicles borne ventrally on very short bases, less than ½ .

Xylorycta austera, ♂ wing venation, K-0817, Kuranda, collected by David Rentz
Xylorycta austera, ♂ genitalia, gvc6451 Townsville, collected by Graeme Cocks.
Xylorycta austera, ♂ uncus and gnathos, K-0817, collected by David Rentz, Kuranda

Xylorycta austera, aedeagus. K-0817, collected by David Rentz, Kuranda

Food plants:
Flight period: January.
Distribution: New South Wales, Queensland. Endemic. (Edwards, 2003).

Remarks: The male genitalia have an unusual bifurcate uncus and closely resemble those of Cryptophasa flavolineata. This bifurcate uncus occurs in the Indian genus Amorbaea Meyrick 1908, and elsewhere in Xylorycta, for example in X. assimilis, but is most unusual for Cryptophasa. 

These two species could be placed together in a genus of their own. There are several closely related unnamed species which could also be placed here.

Barcode results show the two species to be extremely closely related. The main physiological difference is in the wing coloration and shape, X. austera having narrower wings.

Amorbaea subtusvena, Diakonoff 1967, ♂  genitalia
Amorbaea subtusvena, Diakonoff 1967, ♂  aedeagus