Oxyethira (Pacificotrichia) melasma Kelley

Wells, Alice & Johanson, Kjell Arne, 2015, Review of New Caledonian species of Oxyethira Eaton, with description of 17 new species, and new records for Hydroptila Dalman and Hellyethira Neboiss (Trichoptera, Hydroptilidae), ZooKeys 530, pp. 37-90: 61-62

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Oxyethira (Pacificotrichia) melasma Kelley


Taxon classification Animalia Trichoptera Hydroptilidae

Oxyethira (Pacificotrichia) melasma Kelley   Figs 55-57, 105

Oxyethira melasma   Kelley, 1989: 200, figs 37, 45, 59.


A mismatch between the published description and Kelley’s (1989) figures and the holotype specimen in the BPBM labelled " Oxyethira melasma   " is a puzzle. The genital features of the holotype (examined by AW) are as in Fig. 56, and disagree with Kelley’s text description and illustrations (his figs 37, 45, 59) of " Oxyethira melasma   ". However, the tibial spur count of the holotype is 0,2,4, as given by Kelley, and as in the type species. Kelley’s three figures of genital structures agree with the features of a series of specimens, described here as Oxyethira nehoue   and illustrated in Figs 58-60; in contrast to Kelley’s “holotype”, these specimens all have a tibial spur count of 0,3,4.

Oxyethira melasma   Kelley is here redescribed and figured from the holotype specimen. We can only suggest that Kelley had several specimens at hand, macerated one and labelled it “holotype”, but described and illustrated a specimen other than that labelled “Type”. The type has to be the name-bearing specimen and is redescribed here.

Revised diagnosis.

Males resemble Oxyethira nehoue   sp. n., Oxyethira spicula   sp. n., and Oxyethira ouenghi   in having have a more or less triangular median ventral processes in the male genitalia. However, they most closely resemble Oxyethira nehoue   sp. n. from which they are distinguished by spur count 0,2,4, gonopods fused, in ventral view sharply tapered proximally, narrowly parallel-sided distally, rounded apically, apex of phallic apparatus rounded without apical spine, in contrast to Oxyethira nehoue   sp. n. in which the fused gonopods appear triangular in ventral view, and acuminate apically, and ventral process in lateral view sclerotised and arched ventrally.

Revised description

male. Antennae with 19-26 flagellomeres, apical 3 flagellomeres pale, next 5 dark, then 13 pale and basal flagellomeres dark; anterior wing length 1.4-1.9 mm (n=10); tibial spurs 0,2,4; abdominal sternite VII with small sharp median spine, offset from margin.

Male, genitalia (Figs 55-57). Abdominal segment VIII more or less conical, a deep broadly V-shaped excision apico-ventrally. Abdominal segment IX in lateral view broadly bell-shaped; in ventral view rounded proximally, tapered distally, a pair of small short processes apically, each bearing a single seta. Gonopods sclerotised, fused, tapered to narrowly truncate apex, basal setose processes widely separated, slender, elongate, but shorter than fused gonopods, a slender basal apodeme midventrally; subgenital plate broad based, tapered to rounded apex, mostly membranous, but with a small ventrally curved prominence subapically. Phallic apparatus swollen in basal third, narrow in distal 2/3, without apical spine, ejaculatory tube medial.

Material examined.

Holotype. Male, Mountain stream up Boulari River ( BPBM). Other material. 18 males, Province Sud, W part of Plaine des lacs, 150 m downstream bridge at La Capture, 22°15.967'S, 166°49.493'E, 261 m, 04-22.xi.2003, Malaise trap, loc#007, leg. K.A. Johanson ( NHRS); 31males, Province Sud, Mt Dzumac, source stream of Ouinne River, near crosspoint to mountain track, 22°02.073'S, 166°28.460'E, 810 m, 18. xi– 4.xii.2003, Malaise trap, loc#030, leg. K.A. Johanson ( NHRS); 1 male, Province Sud, Mt Dzumac, source stream of Ouinne River, downstream crosspoint to mountain track, 22°01.997'S, 166°28.486'E, 795 m, over about 30 m waterfall, 18. xi– 4.xii.2003, Malaise trap, loc#031, leg. K.A. Johanson ( NHRS); 1 male (on slide), Province Sud, W slope Mt Ningua, Kwé Néco, Stream, at Camp Jacob, 3.7 km WNW summit of Mt Ningua, on Boulouparis–Thio Road, about 50 m upstream road, 21°43.613'S, 166°06.567'E, 150 m, 29. xi– 12.xii.2003, Malaise trap, loc#054, leg. K.A. Johanson ( NHRS); 4 males, Province Sud, Co Rigule Stream, 2.1 km N bridge over Baie de Yaté, 4.3 km S Wé Ngéré, 22°08.147'S, 166° 56.072'E, 14 m, 18.i.2004, light trap, loc#122, leg. K.A. Johanson ( NHRS).


The species was taken at a number of sites in the southern province of the island (Fig. 105).