Thitarodes caligophilus Maczey

Maczey, Norbert, Dhendup, Kuenzang, Cannon, Paul, Hywel-Jones, Nigel & Rai, Tek Bahadur, 2010, Thitarodes namnai sp. nov. and T. caligophilus sp. nov. (Lepidoptera: Hepialidae), hosts of the economically important entomopathogenic fungus Ophiocordyceps sinensis in Bhutan, Zootaxa 2412, pp. 42-52 : 47-51

Thitarodes caligophilus Maczey , sp. nov.

Figs. 25–35

Etymology. Latin for ‘the fog and gloom loving one’; the name refers to weather conditions prevalent during the flight period of this species.

Male. Description based on holotype ( Figs. 25 , 29, 32 ).

SIZE: Wingspan: 44.0 mm; forewing length: 20.0 mm; hindwing length: 17.0 mm; body length: 14.5 mm.

ANTENNAE: Uniformly rust brown.

BODY: Head and thorax red-brown covered densely with ochraceous hairs; prothorax interspersed with some dark brown hairs; abdomen brown, covered in ochraceous yellow hairs.

FOREWINGS: Mainly different shades of grey derived from a mixture of silvery, golden and dark brown scales, mottled with dark brown markings; between C and R uniformly golden grey; narrow sub-terminal fascia grey-white extending from R3 to Cu2, interrupted between M2 and Cu2 by dark spots, basally accompanied by wavelike black fascia of varying width, extending basad towards centres of cells; oval dark brown stigma with small silvery-white discal spot; sub-basal patch of grey-white and black spots; large black spot bordered by a lining of golden-grey scales filling cell between vein A and dorsum reaching distal ¼ of wing length; second large black spot filling the centre of cell between Cu2 and A; borders of spot lobed; fringe dark brown in regular intervals interspersed with yellow scales. Costa straight; Sc unbranched; R2 and R3 stalked, length of stalk about ¾ length from base of R2+3 to margin; R4 and R5 stalked, length of stalk about 1/6 of length from base R4+5 to margin; cross vein R5-M1 well discernible, reaching R5 distad from furcation of R4 and R5; two cross veins between A and CuP; one crossvein between Cup and CuA; A reaching margin.

HINDWINGS: Uniformly dark grey, covered with light brown hairs, slightly translucent; fringe uniformly brown; wing venation similar to forewing but CuP reaching margin; vein A weak, not reaching margin.

LEGS: All legs densely setose with ochraceous hairs, lacking spurs; hind tibia slightly broadened and dorsally densely covered with ochraceous 6 mm long scent-brushes.

GENITAL STRUCTURES: In caudal view tegumen triangular, elongated towards the inner process. Dorsal process of tegumen obtusely lobed and only weakly sclerotised. Caudal margin of tegumen curved outwards in basal half, but almost straight dorso-ventral in inner half (in caudal view). Margin of tegumen curved caudal along inner half, margin smooth. The caudal margin is sclerotised dark brown to almost black; the inner half particularly including the inner process is fully sclerotised. Base of vinculum with evenly curved-shaped dilation. Saccus evenly curved without any indentation. Valve densely hairy, base sclerotised dark brown with acute, spine-like apex; single acute spine diverging from valve at 1/3 of its length. Juxta almost quadratical, posterior end with rounded edges. Aedeagus not sclerotized.

Female. Description based on paratype ( Figs. 26 , 35 ). Similar to male with the exceptions described below.

SIZE: Wingspan: 51.5 mm; forewing length: 24.0 mm; hindwing length: 20.0 mm; body length: 15.0 mm.

ANTENNAE: Uniformly rust brown, dorsally slightly darker.

BODY: Head and prothorax interspersed with some dark brown hairs; abdomen brown covered in brown hairs.

FOREWINGS: Sub-terminal fascia very similar to the one in male, but basally accompanied by wavelike, interrupted black fascia, extending basally towards centres of cells; oval dark brown stigma, bordered by a line of golden scales; large black spot filling centre of cell between Cu2 and A; in centre with silvery-white discal spot, borders of spot lined with golden-grey scales; wing venation as in male.

HINDWINGS: As in male.

LEGS: All legs densely setose with ochraceous hairs, lacking spurs.

GENITAL STRUCTURES: Preanal sclerite triangular, densely setose; lateral arms of prevulvar sclerite rectangular and elongated, densely setose; intergenital lobe rectangular with slightly dilated and rounded corners dorsally, densely setose; intergenital sclerite as slightly curved rectangle.

Holotype. Male, labelled: Bhutan, Namna, N 27°44’02.3’’ E 89°23’32.2’’; Altitude 4,750 m a.s.l., 20.vii.2007, 19:31, Kuenzang Dhendup leg., 10027.

Paratypes (same data as holotype except collection date and label nr.). Female, 19.vii.2007, 09:10, 10028, male, 15.vii.2007, 19:25, 10025; male, 20.vii.2007, 19:25, 10026.

All specimens are deposited at the National Biodiversity Centre (NBC) in Serbithang, Bhutan; holotype collection-nr. 10027; paratypes collection-nr. 10025, 10026 & 10028.

Diagnosis. Thitarodes caligophilus is a medium-sized and only slightly dimorphic representative of its genus. With a wingspan ranging from 44.0 to 47.0 mm males are smaller than the only measured female (wingspan 51.5 mm). In comparison to other species of the genus it is characterised by a rather bluntly rounded apex of the forewings, which display a characteristic colour pattern of different shades of grey. The species can easily be identified by the shape of the valve of the male genitalia with its combination of a spinelike apex plus a single acute spine diverging from the valve at one third of its length ( Figs. 29–34 ).

Discussion. RELATED SPECIES FROM NEPAL. Size and colour scheme differ from Thitarodes species described from Nepal so far. Specimens of T. caligophilus are generally larger although females from T. danieli can be of similar size as T. caligophilus . Colour pattern in this species is characterised by a more uniform pattern of different shades of grey not showing as prominent large spots or fasciae as in the species from Nepal. There are distinctive differences in the male genitalia between all three species described from Nepal. The main difference from T. eberti , the species with the greatest similarities to T. caligophilus , is in the shape of the valve with its combination of a spine-like apex plus a single acute spine diverging from the valve at 1/3 of its length. The latter spine is missing in all species described from Nepal.

RELATED SPECIES FROM CHINA. On the basis of wing venation Thitarodes caligophilus seems to be closely related to T. jialangensis and T. namensis . However, the position of the spine on the valve differs significantly from the species as it does with all other species described from China.

RELATED SPECIES FROM JAPAN. Thitarodes nipponensis is surprisingly similar to T. caligophilus with regards to its wing venation; however, it differs significantly in the shape of the male genitalia, particularly the shape of the valves.

Figures

FIGURES 25 – 28. Thitarodes caligophilus: 25. holotype, male, label 10027; 26. paratype, female, label 10028; 27. paratype, male, label 10025; 28. paratype, male, label 100026.

FIGURES 29 – 35. Thitarodes caligophilus, genitalia: 29 – 31. caudal, 32 – 35. latero-caudal view; 29. & 32. holotype, male, label 10027; 30. & 33. paratype, male, label 10025; 31. & 34. paratype, male, label 100026; 35. paratype, female, label 10028.