Rhithrogeniella ornata Ulmer, 1939

Sartori, Michel, 2014, Status of the enigmatic Oriental genus Rhithrogeniella Ulmer, 1939 (Ephemeroptera, Heptageniidae), ZooKeys 429, pp. 47-61 : 49-55

Taxon classification Animalia Ephemeroptera Heptageniidae

Rhithrogeniella ornata Ulmer, 1939

Rhithrogeniella ornata Ulmer, 1939, male, female imagos and subimagos

Rhithrogena ornata Wang & McCafferty, 2004

Material.

One male holotype, one female allotype: Indonesia, Java, Buitenzorg, VII 1932, Dr. Lieftinck leg. [ZMH]

Paratypes: 4 female subimagos, 1 male subimago: Indonesia, Java, Buitenzorg, Bellevue, caught at light, VII.1929, Prof. Thienemann leg. [ZMH]; 4 female imagos, 2 male subimagos: Indonesia, Sumatra, Padang, VII 1925, Prof. Fulmek leg. [ZMH]; 1 male subimago: Indonesia, Sumatra, Pangkalang, Kota baru, X 1925, Prof. Fulmek leg. [ZMH]

All specimens in ethanol, except fore- and hind legs, fore- and hind wings of the male subimago from Buitenzorg mounted on slide in Canada balsam.

Other material: 5 nymphs: Indonesia, Sumatra Barat, Sawahlunto, stream, 275m, 00°41.33'S, 100°46.72'E, (UN5), 10.XI.2011, M. Balke leg. [ZML]; 26 nymphs, of which two entirely mounted on microscopic slides: Indonesia, Sumatra Barat, Talawi, Ombilin River, 277m, 00°34.15'S, 100°43.54'E, (UN4), 8.XI.2011, M. Balke leg. [ZMH, MZL, LIPI]

Complementary description of the male imago (holotype).

Specimen completely faded; for color patterns see Ulmer (1939).

Mesonotum with transverse suture; medial depression of furcasternum sub parallel anteriorly.

Foreleg with tarsi sub equal in length to the tibia, which is 1.25x longer than the femur. Tarsal composition: 2>3>4>5>1.

Genitalia (Fig. 1): margin of the styliger fig straight to slightly convex, with two small sub-lateral rounded processes; last gonopod segment ca 0.7 × the length of the previous, both together ca 0.75 × the length of the antepenultimate. Penis constituted of two kidney-shape lobes, separated by a “U” incision, i.e. the inner margin of each lobe is concave and slightly hooked near the apex. No lateral or median titillators, no apical spines visible.

Complementary description of the male subimago.

Fore leg (Fig. 2) with femur ca 1.15x the length of tibia, which is subequal in length to tarsi. Tarsal composition 4≥2>3≥1>5.

Hind leg (Fig. 3) with femur ca 1.35x the length of tibia, which is ca 1.45 × the length of tarsi. Tarsal composition 1=2=5>3≥4.

Genitalia (Fig. 4) with penis lobes rounded, ellipsoid, without any spine or titillators; in median position, a pair of membranous processes ending with a spine like sclerotization present in ventral view.

Complementary description of the female imago (allotype).

Thoracic structures similar to the male.

Eggs (Fig. 5): ovoid, ca 130 µm × 90 µm; chorion regularly covered with hexagonal mesh ridges, with KCT in-between, not larger at poles; micropyle rounded to slightly oval in equatorial area.

First description of the nymph.

Size: Body length: up to 5.2 mm and 5.6 mm for male and female respectively; cerci and terminal filament subequal and ca ¾ the length of the body.

Coloration similar to Figs 6 and 7.

Labrum (Fig. 8) moderately expended laterally, ca 2.6 × wider than long; lateral margins regularly rounded; no anteromedian emargination; dorsal face covered with long and thin setae anteriorly; ventral face with shorter and stout setae along the anterior margin. Mandibles covered with numerous long and thin setae on the outer margin; right mandible with outer incisor saw-like, inner one with a trifid apex with 2-3 pectinate setae below it, and 2-3 long and simple setae below the mola; left mandible with outer incisor saw-like, inner one with a bifid apex with 3-4 pectinate setae below it, and 3-4 long and simple setae below the mola. Maxillary palp three-segmented; first segment covered with thin setae on inner and outer margin; second segment with thin setae on the outer margin; third segment slightly pointed, only with long and thin setae. Maxillae with fimbriate scattered setae on the ventral surface (Fig. 13): 13-14 comb-shape setae on the crown of the galea, median ones with 10-11 teeth (Fig. 14); proximal dentiseta bifid, outer margin feathered; distal dentiseta simple, entire and unbranched (Fig. 12). Labium (Fig. 9) with glossae rhomboid, inner margin covered with long and thin setae, apex characteristic with scale-like margin (Fig. 10); paraglos sae moderately expended laterally. Hypopharynx (Fig. 11) with rhomboid lingua bearing a tuft of short and thin setae at apex; superlinguae well developed and expended laterally with rounded apex and setae on the outer margin extended beyond the apex.

Pronotum moderately expended laterally. Foreleg with femur ca 2.6 × longer than wide; outer margin covered with long and stout setae, becoming thinner near the apex; inner margin with only few spine-like setae on the distal third. Outer margin of tibia with very few thin and short setae (Fig. 15), inner margin with few spine-like setae in the middle; tarsi with only a few spine-like setae in the middle of the inner margin. Hind leg similar, except the spine-like setae on inner margin of the femur present on the whole margin; outer margin of tibia with a row of long and thin setae (Fig. 16) and inner margin with more numerous spine-like setae. Middle leg similar to hind leg, except spine-like setae on the inner margin of the femur only present on the distal half. Bristles on the upper face of femora variable in length, always with divergent margins and rounded apically (Fig. 17). Tarsal claw moderately hooked, bearing 4-6 teeth (Fig. 18). No supracoxal spurs present.

Abdomen with posterolateral extensions weakly developed, visible only on segments V–VIII. Gills present on abdominal segments I–VII. Gill I banana-shape (Fig. 20), with fibrillar part well developed, gill IV ca 1.5 × longer than wide, strongly asymmetrical (Fig. 21), gill VI with well-developed fibrillar part, more elongated and slightly asymmetrical (Fig. 22), gill VII ca 2.5 × longer than wide, without fibrillar part and slightly asymmetrical (Fig. 23). Posterior margin of abdominal terga with weakly developed spines of different size and shape (Fig. 19). Cerci and terminal filament with long and stout setae in whorls on the proximal part (Fig. 24), together with long and thin setae in the median and distal part (Fig. 25).

Sequence data.

One specimen has been used for the study by Vuataz et al. (2013) under the name " Heptageniidae 1" in figures and " Heptageniidae sp. 1" in table S1, with one mitochondrial (CO1) and two nuclear genes (H3, wg) sequenced. Access numbers in GenBank are for CO1: HF536605, for wg: HF536598, for H3: HF536591.