Marmenuera ida (Tillyard)

Dean, J. C., Forteath, G. N. R. & Osborn, A. W., 2008, Marmenuera, a new genus of leptophlebiid mayfly (Insecta: Ephemeroptera) endemic to Tasmania., Memoirs of Museum Victoria 65, pp. 43-50 : 47-48

Marmenuera ida (Tillyard)

Figures 17–29

Atalophlebia ida Tillyard, 1936: p. 42 , fig. 7, plate I(10).

Massartellopsis ida Scholes, 1961: p. 30 , plate 2.

Genus W sp.AV2 Dean, 1999: p. 86, figs 242, 243.

Types. Holotype: female imago, Tasmania, Dee Bridge , 7 Feb 1933, R. J. Tillyard ( BMNH) . Paratypes: five female imagos, collected with holotype ( BMNH) ; one male subimago, Lake St Clair , 6 Feb 1933, R . J. Tillyard ( BMNH). Types not examined .

Material examined. Tasmania. 5N, Lake Pedder, Trappes Inlet, February and April 1997, N. Forteath; 3FI (2 reared), 1FS (reared), same location, 1 Feb 1998, N. Forteath; 1MS (reared), same location, 12 Jan 1998, N. Forteath; 1MS (reared), same location, 4 Mar 1998, N. Forteath; 6MI,5FI (all reared), 21N, same location, Nov–Dec 2006, N. Forteath and A. Osborn; 1N, Lake Lilla, Cradle Mountain, 25 Mar 1998, J. Dean; 1N, Dip River Falls, 31 Oct 1998, D. Cartwright; 4FI, Huon River Crossing, 16 Feb 1971, A. Neboiss; 1MI, 1MS, 1FS, D’Entrecasteaux Passage, Exit Cave, Jan1993, A. Clarke.

Description. Male imago. Length: body 11.0– 12.4 mm, forewing 11.2–12.0 mm, caudal filaments 18.4–24.2 mm. Eyes: upper lobes pale pink/brown, in contact on meson of head, lower lobes grey. Thorax: medium-dark brown; pronotum with narrow raised carina along median line, dark brown markings medially on posterior margin, along lateral margins and parallel to lateral margin approximately midway between margin and medial carina. Legs: predominantly yellow, all femora with two broad dark brown bands, one just beyond midlength and the other subapical; tarsal claws similar, each claw with terminal sclerotised hook and opposing ventral process. Forewing (fig. 17): membrane hyaline, stigmatic region slightly opaque, white; all costal, subcostal and R 1 – R 2 crossveins heavily suffused with dark brown, crossveins in vicinity of MA fork also strongly suffused with dark brown; large brown blotch filling area between veins Sc and R 2 at midlength of wing. Abdomen: strongly contrasting pattern of dark brown and yellow; terga 2-7 yellow in anterior half and dark brown in posterior half, yellow colouration extended back as narrow band along median line (fig. 22), extent of yellow colouration increasing from segments 6 to 8, segments 9 and 10 predominantly brown; sterna reddish brown, pale yellow along lateral margins, segments 2-7 with two pairs of small pale spots, the anterior pair more widely eparated than the posterior pair (fig. 23). Genitalia (figs 24–25): penes lobes fused basally, widely separated apically; each lobe relatively broad, apex rounded and turned slightly inwards, subapically with outer margin evenly curved, three moderate sized ventral spines posterior to where the lobes separate. Female imago. Length: body 11.6–14.8 mm.; forewing 12.0– 14.2 mm; caudal filaments 18.2–22.2 mm. Forewing: pigmentation more extensive than in male; dark brown suffusions around costal, subcostal and R 1 – R 2 crossveins broad, almost circular; large brown blotch surrounding MA fork. General colour and abdominal markings similar to male imago. Mature nymph. Body length ranging from 12–16 mm; antennae a little over half length of body; cerci about 1¼–1½ body length, terminal filament a little longer. General colour yellow with brown markings; abdomen with conspicuous pattern of dark brown and yellow, segments 2-8 yellow towards anterior margin and dark brown to the posterior (fig. 26); all legs yellow with dark banding. Mouthparts: Labrum (fig. 27) a little broader than clypeus; maximum width 1.7–1.9 times length along median line; maximum width at about 2/3 labrum length, basal to this the lateral margins relatively straight and diverging; anterior margin moderately concave, with five well developed medial denticles. Legs moderately broad (fig. 28); forefemora length a little over 3 times width, outer margin bearing moderate length spine-like setae and also some longer, hair-like setae; fore-tarsus with 15–20 ventral spines (fig. 29); tarsal claws smooth, without ventral teeth. Postero-lateral spines on abdominal segments 7 (small) and 8-9 (relatively large); posterior margins of abdominal terga with series of large, conspicuous spines interspersed with the occasional shorter spine. Gills lanceolate, lateral tracheae moderately developed.

Remarks. Although the holotype has not been examined the description and, in particular, the image of the female forewing presented by Tillyard (1936) leave no doubt as to the identity of this species. The species is readily distinguished from M. tillyardi in the adult by the abdominal colour pattern, the more extensive pigmentation of the forewing and the structure of the male genitalia, and in the nymph by the abdominal colour pattern and the structure of the labrum and foreleg. Scholes (1961) referred this species to the genus Massartellopsis , presumably based on advice from Edgar Riek ( CSIRO Division of Entomology), but it is now known that the genus Massartellopsis is endemic to South America.

Scholes (1961) suggested the common names “Large Speckled Spinner” and “Large Speckled Dun” for the imago and subimago respectively of Marmenuera ida , and we consider this appropriate.

Keys to species

1. Adults 2

– Nymphs 3

2. Forewings heavily pigmented, crossveins around MA fork suffused with brown (figs 17,19); male imago with outer margin of penes lobes evenly rounded (fig. 24) Marmenuera ida

– Forewings lightly pigmented, crossveins around MA fork not suffused with brown (figs 1,3); male imago with outer margin of penes lobes angular (fig. 7) Marmenuera tillyardi

3. Foretarsus with 15–20 ventral spines (fig. 29); forefemur with spines along outer margin relatively long (fig. 28) Marmenuera ida

– Foretarsus with 30–40 ventral spines (fig. 14); forefemur with spines along outer margin relatively short (fig. 13) Marmenuera tillyardi

Figures

Figures 17–21. Marmenuera ida. Male imago: 17, forewing; 18, hindwing. Female imago: 19, forewing; 20, hindwing; 21, forewing, holotype.

Figures 22–29. Marmenuera ida. Male imago: 22, abdomen, dorsal; 23, abdomen, ventral; 24, penes, dorsal; 25, penes, ventral. Nymph: 26, abdomen, dorsal; 27, labrum; 28, forefemur; 29, foretarsus.