Libethra inchoata Brunner von Wattenwyl, 1907

Murcia, Andres David & Cadena-Castañeda, Oscar J., 2023, The stick insects (Insecta: Phasmatodea) from the Cloud Forest of the Chicaque Natural Park, Colombia, Insecta Mundi 2023 (20), pp. 1-45 : 10-15

Libethra inchoata Brunner von Wattenwyl, 1907

( Fig. 9–12 )

Diagnosis. Body medium-sized (50–57 mm.), in shades of brown, males slim and slender, females robust. Head longer than wide, flat in males or with two prominent irregular tubercles in females; medium-length filamentous antennae. Thorax smooth in males or rough and slightly granular in females. All femora transversely trapezoidal with smooth ventromedial carina, smooth or with small lobes; profemur strongly compressed basally; tibiae without area apicalis. Abdomen smooth or with tiny granules and small foliose structures on tergite VII in females. Poculum large and strongly convex with posterior margin lanceolate and flexed, extending from the middle of the anal segment. Subgenital plate three times wider than long and progressively constricted towards apex, convexly elevated, and carinate on the posterior section. Apex with two points and centrally excavated. Cerci short, flattened dorsoventrally, and curved in males.

Description. Male. Dull brown body coloration. Body smooth, without tubercles or granules ( Fig. 9A–B , 12 ). Head. Smooth and unarmed, distinctively longer than wide, with flattened vertex; eyes spherical and prominent ( Fig. 9C–D ). Antennae reaching the tergite VII ( Fig. 9A–B ); scape wide and rectangular in dorsal view, flattened dorsoventrally; pedicel semi-cylindrical, transversely shorter than scape; third antennomere twice as long as the scape, the other 35 antennal segments variable in length. Thorax. Pronotum smooth, rectangular, longer than wide, but shorter than head, with a transverse suture in the middle ( Fig. 9C–D ). Mesonotum elongated, approximately six times longer than pronotum ( Fig. 9A–B ). Metanotum is as long as half of the length of the mesonotum ( Fig. 9B ). Prosternum compressed anteriorly by the prothoracic coxae. Mesosternum smooth, elongated, with parallel sides. Metasternum half the length the mesosternum, dilating progressively towards the posterior section; metafurcal groove Y-shaped, near the posterior margin. Legs. Pro and metathoracic legs equal in length but longer than mesothoracic legs. All femora transversely trapezoidal, with smooth ventromedial carina, profemora strongly compressed basally. All tibiae with four prominent borders and without area apicalis. Pro- and mesotibiae longer than pro- and mesofemur, metatibia as long as metafemora. Basitarsi elongated as long as the rest of the tarsi combined. Abdomen. Segments smooth. Median segment as long as half of the second tergite, wider than long, anterior margin convex. Tergites II–VII longer than wide; tergites VIII-X with a longitudinal carina; tergite VIII wider than long, widening from anterior margin to posterior one; tergite IX longer than wide, compressing on posterior margin; tergite X wider than the rest of the tergites, divided into two lobes by a smooth carina that crosses it from anterior to the posterior margin, posterior margin is concave with emarginated apex. Sternites I-VI approximately equal in length, with two small closely spaced granules near the posterior margin; sternite VII wider than long, posterior margin convex and abruptly raised, sternite VIII twice as wide as long, traversed from the anterior to posterior margins by a carina and completely elevated above the other tergites. Poculum large and strongly cupuliform, posterior margin lanceolate and flexed, extending to the middle of the anal segment, cerci robust and curved ( Fig. 9E–G ).

Redescription of the female. Body dark brown, smoothly wrinkled, as long as male but more robust ( Fig. 10A–B ). Head longer than wide, with two very prominent irregularly shaped tubercles near the posterior portion of the head; genae granulated, vertex with small spines; eyes spherical ( Fig. 10C–D ). Antennae reach the median segment ( Fig. 10–A ); scape wide, compressed dorsoventrally; pedicel cylindrical in cross-section, and shorter than scape; the others flagellomeres variable in length. Thorax. Rough and slightly granular. Pronotum longer than wide, in dorsal view as wide as head but slightly shorter ( Fig. 10–D ). Mesonotum elongate, 4.5 times longer than pronotum, widening near posterior margin ( Fig. 10–B ). Metanotum gradually widened from its anterior to posterior margin, as long as half the length of mesonotum ( Fig. 10–B ). Prosternum as wide as long, compressed anteriorly by the prothoracic coxae. Mesosternum granular, 4.5 times longer than prosternum, with invaginated mesofurcal groove near posterior margin. Metasternum widened from anterior to posterior margin, with small tubercles and invaginated metafurcal groove near posterior margin. Legs. Long, shape and proportions similar to those in males; mesofemur ventrally smooth, dorsally slightly toothed and basally provided with a pair of lobes on its margins; metafemur dorsally toothed. Pro- and mesotibiae with small spines on their dorsal margins and smooth ventrally, metatibia with a dorsal tooth near its basal area, all tibiae similar in length. Pro and mesobasitarsi as long as the next three tarsomeres combined, metabasitarsus similar in length to following four tarsomeres combined. Abdomen. Robust in dorsal view and grainy textured. The median segment about half as long as tergite II, 2.5 times as wide as long. Tergites II-VII wider than long; tergite VII with a slight foliose prolongation; tergite VIII longer than wide, tapering towards the posterior margin; tergite IX wider than long, with half the length of tergite VIII, narrower and more compressed on posterior margin; tergite X in dorsal view completely covering the subgenital plate, as long as tergite IX but about half as wide, divided by a median suture running through it from anterior to posterior margin, the posterior margin is emarginated in a triangle shape. Cerci reduced, shorter than anal segment, slightly compressed dorsoventrally. All sternites granular, sternites II–VII wider than long; subgenital plate elongated, three times longer than wide, progressively constricting towards the apex and rising convexly from the tergite VIII–IX, posterior portion longitudinally carinate, apex ending in two points centrally excavated ( Fig. 10E–G ).

Measurements (mm). ♂ / ♀ TL: 50.2–50.4 / 55–57, Pr:2.5–3 / 3.5–3.8, Ms:14–15 / 14–16, Mt: 9–9.2 / 6–6.5, MSeg: 1.5–2 / 2–2.2, Pf: 16–17 / 14–15, Mf: 11–12 / 10–11, Hf: 14–16 / 15–17, Pt: 17–20 / 17–18, Mt: 11–13 / 12–12.5, Ht: 15–17 / 16–17, Ant: 38–45 / 30–31.

Eggs. Dark brown and slightly shiny, with a light-colored region surrounding the collar, extending on the dorsal part around the micropylar plate, near the posterior polar zone ( Fig. 11 ). Capsule moderately rough, 1.5 times longer than wide and oval ( Fig. 11B ); dorsal surface progressively narrowing towards the polar zone, ovoid operculum with numerous hairs wholly surrounded by the collar, inserted at an angle of 22° ( Fig. 11A–C ). Micropylar plate on the central region of the dorsal capsule, elongated with conspicuous margin, slightly compressed laterally, inner part slightly rough. Micropylar cup small, extending beyond the posterior margin of the micropylar plate. A prominent midline is reaching the polar zone ( Fig. 11A ).

Measurements (mm). Length: 2.8, capsule height: 1.9, capsule width: 1.6, operculum diameter: 1.2.

Specimens and eggs examined. 7 males and 4 females: 2♂ and 2♀ 4°36′25″N 74°18′38″W. 2301 m. 22 May 2021. 3♂ 2♀ 4°36′22″N 74°18′30″W. 2404 m. 5 June 2021. 2♂ 4°36′43″N 74°18′31″W. 2284 m. 21 January 2017. 7 eggs examined. (CAUD).

Distribution. Only known from its type locality, Bogotá, Colombia.

Comments. A redescription of the female of L. inchoata is provided, comparing with the collected females, which fit the morphological characteristics of the lectotype female, differing in the shape of the leafy projection of the abdomen, which are more developed in the II–III tergites, these are inconspicuous in the female specimens examined here, this character has a variable development, especially in the Libethra species, and may be poorly developed, in an intermediate state, or conspicuous ( Gutiérrez-Valencia et al. 2017). The prolongation of the tergite VII is similar both in the lectotype and in the females studied here. The description of the unknown male and the unknown eggs are also provided.

The association of the two sexes of this species was clarified, because the specimens were usually collected in copulation; morphologically both species differ as mentioned in the descriptions and redescriptions. Additionally, the species were not found together, but rather each species was in a different area and path of the park.

Tribe Diapheromerini Kirby, 1904

Comments. Ramandeun Murcia and Cadena-Castañeda , new genus, is included in the tribe Diapheromerini because it shares the following characters with the other members of the tribe: 1) tibia without area apicalis, 2) abdomen at least as long as or longer than the thorax, 3) femora trapezoidal, in section transverse, 4) profemur not serrated, meso and metafemora not evenly serrated ventrally, 5) antennae distinctly longer than the profemur 6) rarely winged, new genus wingless, 7) anal segment of male not divided or bilobed, 8) eggs without capitulum ( Zompro 2001).

Figures

Figure 9. Libethra inchoata (Male). A–B) Habitus in lateral and dorsal view. C–D) Head and pronotum in lateral and dorsal view. E–G) Terminalia in lateral, dorsal, and ventral views, respectively.

Figure 10. Libethra inchoata (Female). A–B) Habitus in lateral and dorsal view. C–D) Head and pronotum in lateral and dorsal view. E–G) Terminalia in lateral, dorsal, and ventral views, respectively.

Figure 11. Libethra inchoata. Eggs. A) Dorsal view. B) Ventral view. C) Anterior pole.

Figure 12. Libethra inchoata. Live male.