Exphora linnavuorii, Junkiert, Walczak & Bourgoin, 2017

Exphora linnavuorii View in CoL – description of the new colour form ( Fig. 14 View Fig )

Material examined

1 ♂ / Exphora linnavuorii / Junkiert & Walczak det. 2018 [red label]; Coll. R.I.Sc.N.B. / Madagascar ( 2090m) / Plateau Soaindrana [blue label] ( RBINS) .

Description

Description consistent with the holotype of Exphora linnavuorii Junkiert, Walczak & Bourgoin 2017 . Unlike the type specimen whose body is ochre-light brown (metope with keels distinctly red), this form has a light green body throughout (metope with keels distinctly reddish). Wings hyaline, with green veins (veins of the type specimen are light brown). Legs of the type specimen are ochre-light brown (anterior and median legs with darker colour shade), while this form has light green legs with spikes on metatibiae in the same colour as the leg and the sharp end of the spike is black.

Measurements (in mm, only male). Body length: 9.63; head width (with eyes): 1.61; metope length: 1.72; metope width: 0.97; metope length/metope width ratio: 1.77; coryphe length: 0.47; coryphe width: 0.69; coryphe length/coryphe width ratio: 0.68; fore wing length: 8.02; fore wing width: 3.43; mesonotum length: 1.90; mesonotum width: 2.10.

Distribution. Madagascar, Plateau Soaindrana [ 21°31’13.2” S, 47°02’18.6” E] ( Fig. 7 View Fig ).

Ultrastructural characters

The terminology used for specific parts of the body and sensilla is taken from Bourgoin and Deiss (1994), Brożek and Bourgoin (2013) and Schubnel et al. (2019). The use of a scanning microscope allowed to visualize some interesting structures that have not been presented for members of the genus Exphora so far. The images show what the compound eye looks like ( Fig. 15A View Fig ) and how trichoid sensilla are arranged on it ( Fig. 15B View Fig ). They are not evenly distributed and do not adhere to each ommatidium. The antennal pedicel is short and knobbed, with over a dozen sensory plate organs ( Fig. 15C View Fig ). Moreover, the antennae are covered with numerous sensilla chaetica type I, as well as shorter hairs with rounded ends ( Fig. 15D View Fig ). In figure 15C, the flagellum is broken at the base. Figure 16 View Fig shows the whole head in lateral view, with marked structures, in particular the subsequent segments of the labium.

Each metatarsomere is covered with numerous, long trichobothria ( Fig. 17 View Fig ). Distal margins of each metatarsomere bear spikes with longitudinal reticulation. Metatibiae are provided with distinct spines (4 or 5, depending on the species) and sensilla chaetica type II ( Fig. 18 View Fig ).

Figure 19 View Fig presents the ventral surface of the fore wing with description of particular veins and cells, corresponding to the descriptions given above. The SEM images show that in this group of tropiduchids, the pterostigma is not a structural character, but corresponds to an area of pigmentation of certain cells and veins. On the ventral side of the fore wing, a micro-sculpture on the veins is noticeable, which may have a strengthening function ( Fig. 20A,B View Fig ). On the dorsal side of the fore wing, sensilla chaetica type II occur only on the margin of the wing, while on the ventral side they occur all over the margin and on the veins of the membrane ( Fig. 20C,D View Fig ). At the ventral side of the first anal vein (fore wing) campaniform sensilla (mechanoreceptors) and sensilla chaetica type I are present ( Fig. 20E–F View Fig ). The area of microtrichia was found at the costa posterior vein of the fore wing (ventral side) ( Fig. 21A–D View Fig ). Examination of the area where the wing is attached to the body ( Fig. 22A View Fig ) showed that the thorax has a special depression where the postcubitus bulla ( Fig. 22B View Fig ) is hidden when the wings are folded on the body. In addition, the area of microtrichia at the mesopleuron has also been observed, and – while the wings are placed on the body – this area is in contact with the area of microtrichia at the costa posterior vein of the fore wing ( Fig. 22C–D View Fig ). Figure 23 View Fig presents how tegula and basal part of the wing look like, when the fore wing is placed on the body.

The hind wing is covered dorsally with sensilla chaetica type II on each vein (the jugal area was rolled up under the wing so it cannot be seen in the picture) ( Fig. 24 View Fig ). The SEM pictures of both wings show the hamuli in Exphora that allow the wings of insects to remain connected in flight ( Fig. 25 View Fig ). For members of the genus Exphora , the hamuli take the form of a fold at the edge of both wings. A higher magnification shows that the hamuli on the hind wing is covered with spines ( Fig. 26A–B View Fig ). A cuticular micro-sculpture of the fused veins (ScP+R+M) on the proximal part of the hind wing ( Fig. 26C–D View Fig ) was also observed.

Each metacoxa presents a protrusion shaped as a spine ( Fig. 27A–B View Fig ). At higher magnification, a dense pad of microtrichia can be observed ( Fig. 27C–D View Fig ).