Manohyphella keiseri Allen, 1973

Oliarinony, Ranalison, Elouard, Jean-Marc & Sartori, Michel, 2016, Complementary description of the genus Manohyphella Allen, 1973 (Insecta: Ephemeroptera: Teloganodidae), with some comments on its ecology in the Andasibe area (East Coast, Madagascar), African Invertebrates 57 (1), pp. 1-14 : 3-5

Taxon classification Animalia Ephemeroptera Teloganodidae

Manohyphella keiseri Allen, 1973

Manohyphella keiseri Allen, 1973, Pan-Pacific Entomology 49: 160-162; terra typica: Madagascar, Ranomafana

Manohyphella animosa McCafferty & Benstead, 2002, Annals Limnology 38: 44-46; terra typica: Madagascar, Ranomafana, syn. n.

Manohyphella sphyxia McCafferty & Benstead, 2002, Annals Limnology 38: 46-47; terra typica: Madagascar, Ranomafana, syn. n.

Description.

Male imago. Body length: 6.5-7.1 mm; forewing length: 6.8-8.1 mm; hindwing length: 1.11-1.15 mm.

Head: frons dark brown; ocelli whitish with blackish stem; upper part of compound eyes light grey, lower part dark grey; antennae whitish.

Pronotum: light brown, with some blackish maculae and a black sagittal line; foreleg with coxa and trochanter light brown, femur medium brown, tibia dark brown in the basal half, light brown in the apical one, tarsi yellowish brown; leg formula: femur 1.4 mm, tibia 2.5 mm, tarsus 2.15 mm (ta1 0.9 mm, ta2 0.8 mm, ta3 0.3 mm, ta4 0.15 mm); tarsal claw dissimilar.

Meso- metathorax: medium brown, washed with grey; coxa and trochanter washed with black, femur medium brown with two longitudinal blackish stripes, femoro-tibial articulation blackish, tibia and tarsus light brown; tarsal claw dissimilar. Forewing (Fig. 1) translucent with base tinted with dark brown; longitudinal veins medium to light brown, crossveins translucent; a single intercalary between IMP and MP2, one between MP2 and CuA, and three between CuA and CuP; hindwing (Fig. 2) entirely dark brown, costal process pointed and located ca ⅓ along the tip of the wing; mesoscutellum with well-developed posterior processes.

Abdomen: tergites greyish brown, colour intensity increasing toward the tip; presence of two rounded and whitish spots in postero-lateral position of each segment, especially well marked on segments VI–IX; abdominal sternites light grey.

Genitalia (Fig. 5): styliger plate light brown, with a rounded process in the middle of the posterior margin; gonopods light brown, three-segmented, the first one stout, just over half the length of segment II; segment III ovoid and short; inner margin of gonopods bearing stout and short scale-like setae; penes lobes medium brown stout and almost completely fused except at the tip, shorter than the gonopods; no spines or ornamentation present. Cerci broken.

Female imago.

Body length: 6.1-6.2 mm; forewing length: 8.7-9.8 mm; hindwing length: 0.97-1.02 mm.

Similar to the male, except as follows: legs uniformly light brown; forewing (Fig. 3) with subcostal field entirely brownish, hind wing (Fig. 4) light brown, with costal process located ca ⅕ of the tip of the wing; abdominal patterns visible but less contrasted, sternites greyish brown; subanal plate slightly incised in the middle; cerci entirely whitish.

Female subimago.

Similar to the adult female, except general coloration reddish brown, wings entirely medium brown, subanal plate regularly rounded.

Nymph (Fig. 11).

The species has been described by McCafferty and Benstead (2002), with the following important complements:

Patch of setae on the outer margin of the mandibles variable in number and often broken, their insertion only visible at high magnification. Maxilla with a spoon-like tooth, and with two stout and curved dentisetae; patch of setae at the base of the galea composed of 2-5 long, thin setae. Labium with submentum well developed, antero-lateral corners more or less rounded; base of the 3rd segment of the labial palp as wide as the articulation with the 2nd segment.

Gills (Figs 6-10) present on segments I–V. Gill I (Fig. 6) small, finger-like and one segmented, covered with long and thin setae. Gill II (Fig. 7) with a plate like dorsal lobe, and a ventral lobe constituted of costal and anal branches, dorsal gill more or less quadratic, with a distinct longitudinal ridge. In the distal ¼ of the dorsal lobe, a weak line well visible and almost reaching the middle of the plate, probably allowing the larva to lift the distal part of the gill. Dorsal plate of gill III (Fig. 8) quadratic, outer margin concave and with long, thin setae. Dorsal plate of gill IV (Fig. 9) transverse, with long, thin setae on the margin. Gill V (Fig. 10) identical to the previous one, smaller and without ventral lobe. Single postero-median tubercles on tergites variable in size and orientation depending on the developmental stage of the larva. Cerci and terminal filament with rows of stout, long setae.

Ecology.

Manohyphella keiseri larvae were almost exclusively found in the three forested localities (BT, MA, RA) and were virtually absent from the Savoka open canopy localities (4 specimens captured in the three localities in one year), confirming that the species is strictly bound to the forest cover. Populations in BT were not dense enough to proceed to life cycle analyses. Mean densities in MA and RA over the investigated period were 12.50 ± 17.93 and 10.56 ± 11.18 ind. m-2 respectively. Mean biomass was 8.17 and 7.07 mg DW m-2 respectively.

The life cycle exhibits a seasonal pattern which is not characteristic of tropical species (Fig. 12). Mature nymphs were found between September and November, at the end of the dry season.