Amytta digitata, Hemp, Claudia & Heller, Klaus-Gerhard, 2017

Hemp, Claudia & Heller, Klaus-Gerhard, 2017, Revision of the genus Amytta (Orthoptera: Tettigoniidae, Meconematinae) and new species from East Africa, Zootaxa 4263 (2), pp. 295-317 : 297-300

Amytta digitata n. sp. Hemp

( Figs. 1 A, 3 A, 7 A, 8 A, 17)

http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:496651

Holotype male, Tanzania, West Usambara Mountains, Lutindi Forest , 1300 m, December 2014; Depository MfN.

Paratypes. 1 female, same data as holotype but January 2015 ; Depository MfN. Further paratype material: 5 males, 4 females, same data as holotype but October 2014, January, March and October 2015 and June 2016. Collection C. Hemp.

Description. Male. General body shape and colour: Fully alate, small, elongated and of uniformly light yellowish-green colour. Behind eyes two lateral yellow lines, which continue along the whole length of pronotum. Head and antennae: Fastigium of vertex smooth conical, conus between eyes about half the size of first antennal segment. Antennae thin, whitish. Eyes brown-reddish, circular, prominent. Thorax and legs: Cuticle of pronotum shiny with few short scattered hairs. Tegmina and alae fully developed with median brown line along whole length where tegmina touch each other when folded ( Fig. 3 A). Stridulatory area hidden under flap-like elongated posterior margin of pronotum. Fore tibiae with oval and open tympanum, with 5 outer and 5 inner predatory spines, apical with a ventral minute pair of spurs. Mid tibiae mostly with 4–5 outer and 4–5 inner spines. Abdomen: Last tergite transverse and broad with posterior margin broadly incurved. Cerci expanded and shovel-like with subapical expansion, tips also expanded and in-curved ( Fig. 1 A). Near the base of each cercus finger-like process. Subgenital plate elongated, narrowing posteriorly; posterior margin forming two broad round lobes with longish and flattened styli.

Female. As male, fully winged but without brown lines along costal margin of tegmina. Subgenital plate very broad, almost rhombic, broader than long ( Fig. 8 A). Ovipositor of female slender and smooth, only slightly upcurved.

Measurements.

males (n = 3)

Body length 11.4–12.5 Median length of pronotum 3.7–4.0

Length of hind femur 7.8–8.5

Tegmina length 14.5–16.3

females (n = 2)

Body length 10.1–10.9 Median length of pronotum 3.6–3.7

Length of hind femur 9.5–10.0 Length of elytra 18.0–19.0 Length of ovipositor 8.8–9.5 Habitat. Submontane forest.

Distribution. Tanzania, West Usambara Mountains, at present only recorded from Lutindi Forest. Diagnosis. Besides A. pellucida Karsch and A. ukamica Beier , A. digitata n. sp. is fully alate and thus is easily distinguished from all other known Amytta species that are flightless having reduced wings, the tegmina not surpassing the abdomen. A. digitata n. sp. is distinguished from A. ukamica by the completely different male anatomy of the apex. The posterior margin of the last abdominal tergite is undifferentiated, just broadly incurved in A. digitata n. sp. while in A. ukamica two processes are present at the posterior margin of the last abdominal tergite. The male cerci in A. ukamica are differentiated into two complicated wound branches while in A. digitata n. sp. the male cerci are strongly laterally expanded, with a lobe-like expansion subapically. The tips of the cerci are also broadly expanded and strongly inwardly curved. In A. pellucida ( Fig. 1 F) the last abdominal tergite is similar shaped as in A. digitata n. sp. but differences are found in the male cerci which are laterally expanded in both species but differently shaped. In A. pellucida there is no inner finger-like process at the bases of the male cerci as in A. digitata n. sp. ( Fig. 1 A).

Etymology. From Latin digitus = Finger, because of the finger-like appendix at the base of the male cerci.

Figures

FIGURE 1. Detail images of abdominal apices of male Amytta species, dorsal view. A. A. digitata n. sp. B. A. olindo Hemp C. Amytta meruensis n. sp. D. A. hanangensis n. sp. E. A. abbreviata Beier F. A. pellucida Karsch (source OSFO).

FIGURE 3. East African Amytta species. A. Male A. digitata n. sp., Lutindi forest, West Usambara Mountains, 1250 m B. Male A. olindo Hemp, Mt Kilimanjaro, southern slopes, Mrusunga valley, 1600 m C. Male A. merumontana n. sp., Mt Meru, eastern slopes, lower montane forest 1700 m D. Female A. merumontana n. sp., same locality as male.

FIGURE 8. Subgenital plates of female Amytta species. A. A. digitata n. sp. B. A. pellucida C. A. olindo D. A. meruensis n. sp. E. A. hanangensis n. sp. F. A. kilimandjarica G. A. merumontana n. sp. H. A. kilomeni n. sp. I. A. judithae n. sp.