Oecetis magelensis, Wells, 2006

Wells, Alice, 2006, A review of Australian long-horned caddisflies in the Oecetis pechana-group (Trichoptera: Leptoceridae), with descriptions of thirteen new species, Memoirs of Museum Victoria 63 (2), pp. 107-128 : 110-111

Oecetis magelensis sp. nov.

Figures 9–11, 59

Material examined. Holotype. Male, NT, Alligator R. region, Magela Creek , OSS Site 009, 12°42'S, 132°57'E, 17 Jan 1992, Wells ( ANIC).

Paratypes. NT: 24 males, ARR, Magela Creek site 009, 15 Feb 1991, Wells ( ANIC); 5 males, 5 females, ARR, Magela Creek at Rum pipeline, 18–19 Feb 1991, P. Dostine ( NMV) .

Other material. NT: 1 male, Mataranka HS, Roper R., 25 Jan 1977, M.S. and B.J. Moulds ( NMV) ; 1 male, 1 female, 12°42'S, 132°57'E, Kakadu National Park , Magela Creek, OSS Site 009, 28–29 Jan 1991, P. Dostine ( NTM) ; 2 males, 12°42'S, 132°57'E, Kakadu National Park , Magela Creek, OSS Site 009, 15 Feb 1991, Wells ( NTM) ; 3 males, ARR, Magela Creek at Rum pipeline, 1–2 Apr 1991, P. Dostine ( NMV) ; 3 males, 12°42'S, 132°57'E, Kakadu National Park , Magela Creek, OSS Site 009, 1–2 Apr 1991, P. Dostine ( NMV) ; 3 males, 1 female, Jabiru Town Lake , 12°40'S, 132°53'E, 5 Apr 1991, Wells and Webber ( NTM) ; 6 males, 12°42'S, 132°57'E, Kakadu National Park , Magela Creek, OSS Site 009, 24 Apr 1991, Wells and Webber ( NTM) ; 1 male, 1 female, 12°42'S, 132°57'E, Alligator R. Region, Magela Creek , OSS Site 009, 28–29 Apr 1991, P. Dostine ( NTM) ; 1 male, 1 female, Gregory National Park , Limestone Gorge, 25–26 Oct 1991, J. Webber ( NTM) ; 1 male, 1 female, 12°42'S, 132°57'E, Kakadu National Park , Magela Creek, OSS Site 009, 3–4 Feb 1992, P. Dostine ( NTM) ; 1 male, 12°42'S, 132°57'E, Kakadu National Park , Magela Creek, OSS Site 009, 21–22 Mar 1992, P. Dostine ( NTM) . WA: 2 males, 2 females, Maggie Creek , 3 Feb 1978, J.E. Bishop ( NMV) ; 3 males, Maggie Creek , 90 km Kununurra-Wyndham, 3 Feb 1978, J.E. Bishop ( NMV) ; 1 male, stream opposite Dead Horse Gap , Lake Argyle, 19 Feb 1977, J.E. Bishop ( NMV) ; 1 male, 4 females, Lily Creek Waterhole, 15 km W of Kununurra, 22 Feb 1977, J.E. Bishop ( NMV) ; 1 male, 1 female, Dunham R. W of Kununurra, J.E. Bishop , 22 Feb 1977 ( NMV) ; 1 male, Ord R. at Kununurra Dam, 22 Feb 1977, J.E. Bishop ( NMV) .

Diagnosis. Males resemble O. pechana and O. walpolica , the male genitalia appearing closely similar in ventral view, but are distinguished from the former by the shorter phallus with a strongly arched paramere, and from both O. pechana and O. walpolica by features of the inferior appendages: in ventral view, the mesial margin is lined proximally with a row of small setae, then excavated to form a small concavity; apically a cluster of short setae; in lateral view the narrower distal section of the inferior appendages is shorter and more closely resembles that of O. suteri sp. nov.

Description. Male. Forewing slender, length 5.0–9.0 mm, with short hair on veins, dark spots at vein junctions formed by pigmented membrane and darker vestiture; and a single broad patch of scales. Abdominal segments II–IV with tergites darkly scerotised, IX short, pale, slightly produced mid-dorsally, X a simple, membranous plate, triangular distally. Genitalia (figs 9–11). Pre-anal lobes length about 1.5 times width, apically rounded. Phallus membranous, length equal to 2–3 abdominal segments, apico-ventral portion of phallotheca sharply beak-like and down-turned, paramere darkly sclerotised, in lateral view strongly arched dorsally. Inferior appendages stout throughout length in ventral view, apically rounded, mesial margin lined proximally with short setae, abruptly excavated at about two-thirds length, with a pouch meso-dorsally on basal section; in lateral view stout, with a short, rounded lobe dorsally.

Distribution. Found in the north of WA and the NT.

Remarks. Oecetis magelensis is difficult to distinguish from O. walpolica , but has the inferior appendages in lateral view with distal narrower section shorter and in ventral view tending to converge, whereas in O. walpolica the inferior appendages tend to turn outward toward apices.