Valalyllum folium, Deranja & Kasalo & Adžić & Franjević & Skejo, 2022

Deranja, Maks, Kasalo, Niko, Adzic, Karmela, Franjevic, Damjan & Skejo, Josip, 2022, Lepocranus and Valalyllum gen. nov. (Orthoptera, Tetrigidae, Cladonotinae), endangered Malagasy dead-leaf-like grasshoppers, ZooKeys 1109, pp. 1-15 : 1

Valalyllum folium sp. nov.

Fig. 2

Material examined.

Holotype. Madagascar • 1 ♂; East Madagascar, Belanono, " 30 km SW de Sambava , sur la route d’Andapa” [along the road to Andapa]; Valdon and Peyrieras leg.; MNHN.

Diagnosis.

Large (> 11 mm long), apterous, leaf-like, rectangular, and cryptic species endemic to northern Madagascar. Antennae are short and filiform, composed of 15 antennomeres. Upper margins of the antennal groove in the level of the lower margin of a compound eye. Frontal costa bifurcates between the eyes into parallel facial carinae (more rounded in Lepocranus ), between which there is a wide scutellum, as wide as a compound eye. Vertex obliquely projected above the eyes in the frontal view. Vertex about 3 times wider than a compound eye (measured at its widest part as seen in the frontal view). In the frontal view, a compound eye is ovoid (rounded in Lepocranus ). Pronotum is rectangular and 1.75 times as long as high (2.4 times in Lepocranus ) because of the compressed and elevated median carina. In the dorsal view, the median carina of the pronotum is sulcate. Median carina of the pronotum is undulated in a sinusoid fashion in the dorsal view (straight in Lepocraus ). Pronotum dips above the head in dorsal view, then smoothly curves upwards and sharply descends towards the posterior apex. The posterior slope of the pronotum is abrupt (gradual in Lepocranus ), forming a right-angle (obtuse angle in Lepocranus ), and undulated. The posterior apex of the pronotum is bilobated in the dorsal view. Pronotum covers the whole abdomen (last segments not covered in Lepocranus ). Dorsal margin of the hind femora bears three small projections (lappets). Genicular and antegenicular teeth are small and angular. Mid tibia is stout. Top margins of the mid and the fore femora lack tubercules. Pulvilli of the hind tarsi are rounded.

Etymology.

The specific epitheton is a noun in apposition, from Latin " folium, -i, n. " leaf, because of the species’ leaf-like morphology.

Proposed vernacular name.

Malagasy Litterhopper

Description.

Holotype (male). General appearance. Valalyllum folium gen. et sp. nov. is a large (> 11 mm); smooth; rectangular; cryptic; dead-leaf-mimicking species with fine leaf-like venation on the elevated part of pronotum; uniformly brown except for the yellowish tarsi of all legs, as well as pale-yellowish hind tibiae.

Head. Antenna (Fig. 2B, C ) short, filiform, composed of 15 antennomeres. The first segment is the largest scapus, second is a barrel-like pedicel, both circular in cross-section, while the remaining 13 antennomeres make up the flagellum. Segments 3rd to 6th are basal segments of the flagellum and they are robust, about two times as long as wide. Segments 7th to 10th are the central segments, and they are elongated, from four to five times as long as wide. Segments 11th to 13th are the subapical segments, shorter and bulkier than the mid segments. Last two antennomeres, i.e., 14th and 15th are reduced apical antennomeres. In the frontal view (Fig. 2B, C ), the vertex is 3 times wider than the width of the compound eye (1.2 mm wide vertex, 0.4 mm wide compound eye); the vertex tip is above the top margin of the compound eyes, forming a smooth convex bulge. Frontal costa is smooth before the bifurcation, without visible projections or teeth. Bifurcation of the frontal costa is situated just below the line connecting the mid portion of the compound eyes. Height of the compound eye is greater than the height of the scutellum. Compound eye is ovoid. Width of the compound eye is the same as the width of the scutellum. Scutellum in its widest part and at the level of antennal groove is significantly wider than the antennal groove. Facial carinae are visible, and run straight after the bifurcation. Facial carinae are however, slightly sub-parallel, so the scutellum is slightly widened at the level of the median ocellus. Facial carinae are compressed and elevated but smooth. Paired ocelli are situated below the line connecting the mid portion of the compound eyes, but above the lower margin of compound eyes. Top margin of the antennal groove is placed at the level of the bottom margin of the compound eyes. In the lateral view (Fig. 2A ), both vertex and face are visible around an ovoid compound eye. Fastigium protrudes beyond the furthest margin of the compound eyes for a half of the compound eye width. Occipital area is visible and narrow. In the dorsal view (Fig. 2D ), the vertex is 3 times wider than the width of the compound eye. However, in this view, the vertex is also visibly very short and reaches to about a third of the compound eye length, i.e., it is not projected, but indrawn. Lateral and transverse carinae are slightly visible and elevated. Medial carina not visible due to pronotal occlusion.

Pronotum In the frontal view (Fig. 2C ), the pronotum is visible above the head as a large, compressed and elevated and undulated projection with sulcated (ditched) ridge. In lateral view (Fig. 2A ), the pronotum has the appearance of a dead leaf, because of the strongly compressed and elevated median carina of the pronotum. Prozonal and extralateral carinae are invisible. The pronotum is long (13.4 mm) and high (7.6 mm), giving a rectangular shape to the insect. Tip of the median carina of the pronotum has striped pale-dark-pale-dark coloration. Anterior margin is projected above the head as an oblique projection and then goes in circular fashion towards the dorsal portion, where it becomes the highest in the level of the mid coxae. After its highest portion, the dorsal margin of the median carina slowly decreases in height, and then in the level of the subgenital plate it abruptly falls in almost rectangular angle. The whole distal portion of the pronotum after this abrupt slope is finely toothed and undulated. Ventral sinus of the pronotum is large and visible, while tegminal sinus lacks because of the absence of wings. Infrascapular area, covered by the hind femora, is wide, smooth and convex. The compressed dorsum of pronotum is finely granulated and intercepted with many fine veins (carinulae), giving an insect even more credible dead-leaf mimicry. Paranota are triangular, with truncate-oblique apex. In the dorsal view (Fig. 2D ), the median carina has a sulcated ridge and forms a sinusoid undulation from the head caudad. The pronotum is finely granulated. Prozonal and extralateral carinae are absent, not visible. No pronotal projections visible. Shoulders (humeral angles) oblique, not projected outwards. Posterior apex of the pronotum is widely bilobate.

Legs. Fore legs (Fig. 2A, C, D ). The fore femur is stouter than the mid one, length/width ratio is about 3.1. The dorsal margin of the fore femur has a continuous carina without tubercles. Ventral margin with the same femur has one tubercle close to the femur’s distal end. The fore tibia is finely serrated and rectangular in cross-section. Distal segment of the fore tarsus is much longer than the proximal one. Mid legs (Fig. 2A, D ). Dorsal and ventral margins of the mid femur bear continuous carinae, but ventral carina also has three small tubercles. Length/width ratio of the mid femur is 3.7. The mid tibia is finely tuberculated and rectangular in cross-section. Distal segment of the fore tarsus is much longer than the proximal one. Hind legs (Fig. 2A, D ). The dorsal margin of the hind femur bears three large, but relatively blunt teeth. Ventral margin with continuous carina. Length/width ratio of the hind femur is 2.7. The hind tibia bears numerous strong teeth, but otherwise has a very smooth surface. First segment of the tarsus bears three strongly protruding, smooth and rounded pulvilli. First tarsal segment is much longer than the third.

Measurements

(male holotype). Body length (from the tip of head to the tip of the subgenital plate) 11.3 mm. Pronotum length 13.4 mm. Pronotum maximum height 7.6 mm. Pronotum width between lateral lobes 5.2 mm. Pronotum width between the shoulders 3.5 mm. Eye width 0.4 mm. Vertex width 1.2 mm. Fore femur length 2.5 mm. Fore femur width 0.8 mm. Mid femur length 3.3 mm. Mid femur width 0.9 mm. Hind femur length 7.5 mm. Hind femur width 2.8 mm. Hind femur length/width ratio 2.7.

Locus typicus.

Madagascar, Sava region, Belanono (rainforest between Sambava and Adapa).

Proposed IUCN Red List Assessment.

Similar to the Leatherback Pygmy Grasshopper ( Lepocranus fuscus ) ( Danielczak et al. 2017), the Malagasy Litterhopper ( Valalyllum folium gen. et sp. nov.) should be immediately listed as an endangered species in the IUCN Red List because (1) of a very small geographic range it inhabits (known from a single locality, (2) the population might be fragmented and (3) the decline in both the number of mature individuals and the size and quality of the range because of expected severe deforestation.

Figures

Figure 2. Valalyllum folium gen. et sp. nov. from Madagascar, male holotype, deposited in MNHN Paris. A habitus in left lateral view B head in frontal view C habitus in frontal view D habitus in dorsal view. Photo J. Skejo and MNHN Paris.