Scaria sp.

Kasalo, Niko, Deranja, Maks, Adzic, Karmela, Sindaco, Roberto & Skejo, Josip, 2021, Discovering insect species based on photographs only: The case of a nameless species of the genus Scaria (Orthoptera: Tetrigidae), Journal of Orthoptera Research 30 (2), pp. 173-184 : 173

Scaria sp.

Material examined. -

Peru •1 M, 1 F; Department of Amazonas: Bongará Province: Peroles near Yambrasbamba , mountain rainforest belonging to the Peruvian Yungas biogeographic ecoregion; 5.67°S, 77.92°W; 1905 m a.s.l.; 19 August 2008; R. Sindaco leg.; photographs only, available on iNaturalist (https://www.inaturalist.org/observations/9968031), supplemented by Figures in this publication .

Habitat. -

The specimens were observed and photographed on the ground inside a well-preserved patch of forest with muddy base covered by abundant leaf litter; tree trunks were covered by mosses, rich epiphytic vegetation (many Bromeliaceae ), and arboreal ferns.

Specific traits. -

The main differences between Scaria sp. and the five other morphologically similar species that occur in the region are listed in Table 2 . The unnamed species is easily distinguished from other Scaria species by the following set of characters: 1) vertex wider than in any other known Scaria species, 2) small apical teeth on mid femora (in almost all the other species, teeth are larger), 3) longer fore and mid femora (length/width ratio of 6 or more) than in any other species, 4) generally stouter appearance than any other Scaria species, 5) yellow stripe placed medially on tegmina, and 6) distinctive coloration pattern of pronotum. Concerning the key to Scaria species by Cadena-Castañeda et al. (2019), our unnamed species shows a unique combination of characters not present in any other known species, namely yellowish face, eyes projected above the dorsalmost level of tegmina, absence of dorsal midline (coloration), lightly colored stripe covering the median part of tegmina, and absence of stripe on the upper half of the lateral margin of pronotum. The only Scaria species similar to this unnamed one is Scaria veruta (Grant, 1956), which also has longer fore and mid femora.

Morphological description. -

General characters and coloration: Relatively slender body, slightly stouter than other Scaria species described so far. Body smooth, without warts or dorsal projections. Coloration pattern of the entire body homogeneous, with interchanging black and yellow coloration. Yellow coloration varying from dark to paler yellow (close to white coloration) in some parts of the body. Antennae black, sometimes with a paler tip. Head exhibiting similar coloration and texture to that of the rest of the body, with black stripe behind the eyes. Compound eyes pale at the top, otherwise black. Carinae of pronotum (interhumeral carinae, external lateral carinae, internal lateral carinae, prozonal carinae, and median carina) mostly yellow to light yellow. Fore and mid femora black with all carinae yellow; fore and mid tibiae following the same pattern. Hind femora bearing a yellow to light yellowish stripe in the mid part. Front and mid tarsi dark; hind tarsi lighter but with dark coloration on the first segment ventrally. Tegmen black with a yellow longitudinal stripe in the middle covering more than three quarters of the area of the tegmen.

Head: (Fig. 2A, E ) Antennae with 20 antennomeres. Scapus oval in cross-section. Short axis of the scapus 1.5 times wider than second antennomere (pedicel); long axis 2 times wider than second antennomere. Second antennomere 1.5 times wider than the third and all other antennomeres. Basal antennomeres from 3rd to 7th, central antennomeres from 8th to 14th, preapical antennomeres from 15th to 17th, and apical antennomeres final three segments (18th to 20th) reduced. Pale rings in joints visible in central segments. In fronto-lateral view: Frontal costa bifurcates above the middle of the compound eyes (Fig. 5 ). Head below level of pronotum (head in contact with the underside of the anterior side of pronotum). Lateral ocelli barely above mid-level of a compound eye. Fastigium verticis barely below level of dorsal margin of a compound eye. Frontal costa bulging for half the length of scapus. Pedipalps white. Transverse carinae concave. Fossulae deep and pronounced. Median carina absent. In dorsal view: Vertex the same width as compound eye (male) or 1.7 times as wide as compound eye (female). Eyes of a bulbous kidney shape. Frontal costa not straight after bifurcation (see Fig. 4A ).

Pronotum: Frontal view is not seen in the photographs. In lateral view: Pointy short frontomedial (anterior spine) present in the anterior margin. Prozonal carina visible, yellow in coloration. Sulci visible, dark in coloration. Humeroapical carina connected with external lateral carina, both yellow in coloration. Posterior margin of the lateral lobe yellow/pale with ventral sinus more obtuse than tegminal sinus. Pronotal disc flat; median carina flat except on the places of promedial and first metamedial projections. Pronotum reaching far beyond hind knees. Extralateral carina not visible, but a yellow spot in its place. Infrascapular area virtually non-existent. In dorsal view: Pronotum covering the whole abdomen. Pronotal apex surpassing hind femora. Coloration of pronotum similar to rest of body. promedial projection with characteristic yellow coloration. Prozonal carinae parallel. Humeral angles slender, oblique. Pronotal process bearing yellow to pale yellowish x-shaped mark. Median carina present, clearly visible thanks to the contrast in coloration, but rather flat. Internal lateral carina yellow to pale yellow and clearly visible. Posterior margin of pronotum truncated. Interhumeral carina absent. Characteristic yellow line visible in the area where an interhumeral carina is usually present.

Wings: Macropterous specimen. Wings (alae) well developed, visibly longer than pronotum, black with white anterior edge. Tegmina present; reaching coxa of hind legs; black with thick yellow medial stripe from anterior to posterior part of tegmen.

Legs: Fore legs: Femora and tibiae smooth, without teeth. Yellow and black stripes following visually unperceivable carinae on femora. Fore femora 6 times longer than wide. Yellow and black stripes present on tibiae as well. Tarsi two segmented. Proximal segment much shorter than distal. Mid legs: Femora and tibiae smooth except for the apical (genicular) teeth present and clearly visible in distal part of femora. Yellow and black stripes, which are 6 times longer than wide, following virtually non-existent carinae on femora. Yellow and black stripes present on tibiae. Tarsi two segmented, proximal segment much shorter than distal. Hind legs: Femora 3.6 times longer than wide. Dorsal margin with minuscule teeth along dorsal margin. Genicular and antigenicular teeth clearly visible, but small. Ventral margin smooth. Inner external area of hind femora with a few transverse ridges of yellow color. In the mid length of femur, a transverse yellow to pale yellow band is present. Tibiae yellow in dorsal, black in ventral part, with recognizable miniscule teeth on dorsal margins with few larger, but still tiny, teeth. Third segment of arsus (Fig. 2C ) 1.4 times longer than proximal segment. Tarsal pulvilli orbicular, first and second of same length, third (= distal) 1.4 times longer than first two. Proximal segment of tarsus in dorsal part yellow to light yellowish; in ventral part black, but tarsal pulvillus pale.

Sexual dimorphism. -

This unnamed species exhibits marked sexual dimorphism in general appearance of sexes, vertex width, pronotum stature, and coloration. Some of the observed differences could be due to the limited sample, i.e., we have examined photographs of only one male and one female, but we nonetheless decide to discuss them as they could prove to be useful in the future. Vertex: Ratio of vertex width and width of compound eye in dorsal view much higher in female (1.7) than in male (1). Pronotum: Ratio of width between prozonal carinas and the width between humoral angles are equal in both sexes. However, the ratio of the length of the pronotum and the widest width between the humeral angles is much less in the female (5.15) than in the male (5.7). Coloration: Observed pattern of coloration is almost identical in both sexes, with varying degrees of color saturation in certain areas. Legs in male appear more saturated than in female. Pronotum of female appears more saturated than that of male.

Limits of the description from photographs. -

Since some angles are missing from the pictures, certain characters were described incompletely or were not described at all. We must stress, once again, that those characters do not limit us in concluding that this is a new species, but could limit the comparison with future specimens or photographs. The following is a list of characters seen only in frontal and ventral views, which should, for detailed description, be examined in a laboratory environment when a physical specimen is collected. Frontal view: level of bifurcation of the frontal costa; scutellum width; position of the antennal grooves; distance between the antennal grooves; position of lateral ocellus; shape of the vertex. Ventral view: shape of thoracal and abdominal sternites (incl. sternomentum and subgenital plate).

Measurements. -

No specific measurements can be given due to lack of physical specimens, but some specific proportions can be calculated from photographs (see Table 2 ).

Figures

Figure 2. Example of AI enhancement of Scaria sp. body details compared to original photography in the background. A. Upper part of the head, showing an eye, a scapus, and a pedicel; B. Ovipositor; C. Hind tarsus; D. Ventral and tegminal sinuses; E. Bottom part of the head, showing the mouthparts. Photo credit: Roberto Sindaco.

Figure 4. Living female of Scaria sp. in A. Dorsal view; B. Lateral view. Photo credit: Roberto Sindaco.

Figure 5. Living female of Scaria sp. in frontolateral view. Photo credit: Roberto Sindaco.