Afroagraecia nguruensis, Hemp & Heller, 2019

Hemp, Claudia & Heller, Klaus-Gerhard, 2019, New Agraeciini species from the Eastern Arc Mountains, East Africa (Orthoptera: Tettigoniidae; Conocephalinae; Agraeciini), Zootaxa 4664 (3), pp. 301-338 : 320-322

Afroagraecia nguruensis n. sp. Hemp C.

( Figs. 26 , 27 A ; 28 A–C; 29 A, B, 40, 42, Table 1 )

Holotype: male. Tanzania, Nguru Mountains , Morogoro District, submontane forest, November 2017. Depository: collection C. Hemp.

Further paratype material: 5 males, 7 females, 1 male nymph, same data as holotype and February 2017, June 2017 and January 2018. Depository: collection C. Hemp.

Description. Male ( Fig. 26 A ). General habitus and coloration. Uniformly to mottled brown, most specimens with dark to light brown median fascia from head over disc of pronotum; face with black triangle as typical for most other species of Afroagraecia . Head and antennae. Fastigium verticis dorsally dark brown, conical, laterally compressed, shorter than scapus, tip acute. Cuticle of head slightly wrinkled, shining. Ocellus cream coloured. Antennae more than twice the length of body, thin, of brown reddish colour with irregular darker spots along length. Thorax. Pronotum in most individuals with brown to black median fascia, somewhat constricted on mesozona and then widening on metazona, sometimes interrupted or obsolete ( Fig. 26 A ). Anterior margin of pronotum rounded, posterior margin truncate; metazona slightly elevated. Lateral lobes of pronotum rounded, at height of metazona margin incurved. Prosternum bispinose; meso- and metasterna unarmed. Tegmina and wings slightly shorter than body length. Tegmina with numerous dark spots on light brown surface. Legs. Fore coxa with well-developed spine. As in A. mangula spination of femora variable, different numbers of spines were counted even within one individual between each pair of legs. Fore femora with 3–4 outer and 1–2 inner ventral spines; mid femora with mostly 3 (sometimes 4) outer ventral spines, inner side unarmed. Hind femora with 4–6 dark spines on outer ventral side, unarmed on inner side or with a tiny spine near joint with tibia in some individuals. Abdomen. Tenth abdominal tergite shield-like, posterior margin medially slightly incurved, cuticle shiny. Supra-anal plate finger-like elongated, basal half deeply sulcate, proximal part rounded. Male cerci with broad base, densely hairy and two inner processes ( Fig. 27 A ), the basal one blunt and longer than spine midway. Apices of cerci narrow ending in two acute black sclerotized spines. Subgenital plate elongate, posterior margin v-shaped incurved and with two short styli.

Female. General coloration as in male. Slightly larger than male. Ovipositor long, slender and slightly up- curved ( Fig. 26 B ). Subgenital plate triangular with pointed apex ( Fig. 29 A ).

Measurements, males (mm) (N = 5). Body length 24.4–29.1. Length of pronotum 6.9–7.9. Length of elytra 16.1–18.8. Length of hind femur 13.7–14.4.

Measurements, females (mm) (N = 5). Body length 24.8–29.6. Length of pronotum 6.8–7.4. Length of elytra 19.5–21.5. Length of hind femur 15.2–16.3. Ovipositor length 14.5–16.8.

Song. The recorded male produced relatively long (mean duration ca. 20 seconds) sequences of syllables (SRR ca. 19 Hz). See Fig. 40 , 42 and Table 1 for details.

Diagnosis. A long-winged species morphologically very similar to A. mangula Hemp, 2017 . All specimens of A. mangula have a well developed dark fascia on the pronotum, often divided into four dark stripes on the metazona. In A. nguruensis n. sp. the pronotal fascia is not as well developed, often even obsolete. On the metazona the fascia is sometimes also divided into four stripes, as in A. mangula but mostly the fascia is obsolete on the metazona or reduced to small brown dots at the posterior margin of the pronotum. A. mangula is generally slightly larger in body size and stouter, especially the females. The tegmina are slightly longer in A. mangula compared to A. nguruensis n. sp. Differences are seen when comparing the male cerci. In A. nguruensis n. sp. the inner basal spine or process is blunt ( Fig. 27 A ) while it is short acute and sclerotized in A. mangula ( Fig. 27 B ). Also A. kisarawe is morphologically similar to A. mangula and A. nguruensis n. sp. However, A. kisarawe is a fragile and smaller species and the male cerci show differences, compared to A. mangula and A. nguruensis n. sp. ( Fig. 27 C ). In A. kisarawe both inner processes are thick and blunt, and may be reduced in some specimens. Differences between A. nguruensis n. sp. and A. mangula are also seen in the morphology of the tegmina—the shape of the stridulatory file (compare Fig. 28 A, C and D, F ) and the mirror area ( Fig. 28 B and E ). Except for slight differences in general body size ( A. mangula being slightly larger than A. nguruensis n. sp.) and differences in the expression of the pronotal fascia (mostly faint to obsolete in A. nguruensis n. sp.) females of both species are difficult to distinguish. But since A. mangula is restricted to the forested areas of the Udzungwa Mountains National Park and A. nguruensis n. sp. (compare Fig. 29 A–D) to the Nguru Mountains further north best distinguished by area of occurrence.

Habitat. On branches and leaves on bushes and trees in understorey vegetation in closed forest.

Distribution. Tanzania, submontane forest.

Etymology. Named after the Nguru Mountains of Tanzania.

Figures

FIGURE 26. Afroagraecia nguruensis n. sp. Male (A) and female (B).

FIGURE 27. Male cerci of Afroagraecia species. A. A. nguruensis n. sp. B. A. mangula C. A. kisarawe.

FIGURE 28. Tegminal characters of Afroagraecia nguruensis n. sp. (A–C) in comparison with A. mangula (D–F). A, D. Stridu- latory area on upper side of left tegmen B, E. Mirror area on upper side of right tegmen C, F. Stridulatory file on underside of left tegmen.

FIGURE 29. Subgenital plates of female Afroagraecia species. A, B. A. nguruensis n. sp. (A, preserved, B, freshly killed specimen) C. A. mangula D. A. kisarawe.

FIGURE 40. Oscillograms of the calling song of Afroagraecia species.

FIGURE 42. Power spectra of the calling song of Afroanthracites, Afroagraecia and Dendrobia species. In A. guttatus the restricted frequency range is marked by a black line at its end.