Gymnoscirtus corifterus, Hemp, 2020

Hemp, Claudia, 2020, New species of Mecopodinae (Orthoptera, Tettigoniidae) from Tanzania, Zootaxa 4790 (1), pp. 138-150 : 142-146

Gymnoscirtus corifterus n. sp.

( Figs. 7–11 )

Holotype male. Tanzania, Udzungwa Mountains National Park , Sonjo Trail, submontane forest, May 2019, about 7°45´15´´ S 36°53´24´´ E. Depository: CCH. 2 males, 1 female, same data as holotype and August 2019.

Description. General body shape and colour: elongated but stout body, of predominantly dark brown colour ( Fig. 7 A, C ). Head and antennae.—Antennae about 1.5 times of the body length, about 4.5 cm long, thin and of same colour as body. Fastigium verticis typical for Gymnoscirtus – globose, width between scapi about 2.3– 2.3 mm and thus 3.8 times the width of one scapus ( Fig. 8 A, C ); met by fastigium of the face by broad line ( Fig. 8 A ). Thorax.—Pronotum with typical „hourglass“ shape, lateral sides deep black ( Fig. 8 C ); disc of pronotum rather smooth with numerous impressed dots, lateral lobes more rugose, deeply cut by first and second sulcus. Tegmina strongly reduced to tiny lobes, hardly protruding from posterior margin of pronotum ( Fig. 10 A , arrow). Legs.—Legs long and slender, base of hind femur more stout. Hind femora surpassing apex of body about 1.5 times of their length, hind tibiae as long as femora. Tympana of fore tibiae oval and open on both sides. Fore and mid femora roundish, unarmed. Hind femora with double row of irregular set spines at posterior part. Fore and mid tibiae almost quad- rangular in diameter; with double row of numerous ventral spines. Fore tibiae dorsally with 1–3 spines at outer side, inner side unarmed. Mid tibiae with a double row of 2–3 irregular set dorsal spines. Hind tibiae quadrangular with a dense double row of ventral spines and less densely set double row of dorsal spines. Abdomen.—Abdominal tergites medially from segment 2 onwards with rounded knobs getting gradually larger to 9th abdominal segment; 10th abdominal segment this median knob is inconspicuous. Cerci short and comparatively thick, slightly incurved; base of cerci bulbous, strongly narrowing at about middle, remaining part slightly laterally compressed ( Fig. 9 A ). Subgenital plate long with a narrow middle part, fork v-shaped with blunt apices ( Fig. 9 C ). With tiny styli.

Female. Larger than male ( Fig. 7 B, D ) with same „hourglass“ -shaped pronotum with deep black markings at lateral lobes ( Fig. 11 A ). Tegmina very tiny longish structures lateral protruding from pronotum ( Fig. 10 B ). Legs as in male. Ovipositor stout and slightly up-curved at posterior part ( Fig. 7 B ). Subgenital plate broad plate, posterior and anterior margins slighly in-curved medially ( Fig. 11 C ).

Measurements, males (mm) (N = 3). Body length 24.4–27.4. Length of pronotum 4.7–5.4. Length of hind femur 26.5–28.3.

Measurements, female (mm) (N = 1). Body length 26.1. Length of pronotum 5.3. Length of hind femur 29.3. Ovipositor length 20.2.

Diagnosis. The easiest character to distinguish G. corifterus n. sp. from G. unguiculatus is the presence of shortened tegmina in the male of G. unguiculatus and lateral lobes not touching each other but being well visible in the female while G. corifterus n. sp. has tiny rests of the tegmina only in both sexes (compare Figs. 8 , 10 , 11 ). The male of G. corifterus n. sp. has short incurved cerci while G. unguiculatus has slender and long cerci ( Fig. 9 A, B ). Also, the subgenital plate is morphological different between the males of the two species. While G. corifterus n. sp. has a v-shaped fork apex, typical for many Mecopodinae (and for Apteroscirtus , see above), in G. unguiculatus the fork is rounded with a short inner dent and tiny styli ( Fig. 9 B, D ). Females are very similar in size and body shape and also the subgenital plate shows little distinguishing characters. However, while in G. corifterus n. sp. the female subgenital plate is inwardly curved at both its margins, the margins of the subgenital plate in G. unguiculatus are almost straight ( Fig. 11 C, D ).

Habitat. Found in litter and on herbs a night in submontane wet forest.

Distribution. At present only known to the Udzungwa Mountains National Park in Tanzania.

Etymology. From Greek: - coris, without and fterá = wings since the new species has almost completely reduced tegmina.

Figures

FIGURE 7. Habitus of Gymnoscirtus corifterus n. sp. A, C. Male, lateral and dorsal B, D. Female, lateral and dorsal.

FIGURE 8. Morphological details of Gymnoscirtus species. G. corifterus. sp. face (A) and dorsal view of head and pronotum. Arrow points to the strongly reduced tegmen of the left side. G. unguiculatus, face (B) and dorsal view on head and pronotum (D).

FIGURE 9. Morphological details of Gymnoscirtus species. G. corifterus n. sp., dorsal view on male apex (A) and subgenital plate (C). Gymnoscirtus unguiculatus, dorsal view on male apex (B) and subgenital plate (D).

FIGURE 10. Reduced tegmina (arrows) of male Gymnoscirtus corifterus n. sp. (A) and female (B).

FIGURE 11. Female Gymnoscirtus species A, C. Dorsal view on head and pronotum of G. corifterus n. sp. (A) and subgenital plate (C) B, D. Gymnoscirtus unguiculatus, dorsal view on head and pronotum (B) and subgenital plate (D).