Tenerasphaga mpwapwae, Hemp & Heller, 2019

Hemp, Claudia & Heller, Klaus-Gerhard, 2019, Orthoptera (Tettigoniidae and Acridoidea) from Miombo woodlands of Central Tanzania with the description of new taxa, Zootaxa 4671 (2), pp. 151-194 : 167-170

Tenerasphaga mpwapwae n. sp. Hemp C.

( Figs. 15–20 )

Holotype. Male. Tanzania, Mpwapwa District, Dodoma Region, grasslands between maize fields on the Mpwapwa plateau, 1850 m, March 2017 . Paratypes 3 males, 2 females, same data as holotype. Depository: Collection C. Hemp .

Description. Male. General habitus and colour pattern. Predominantly green with brown-reddish and yellow fasciae on pronotum, on stridulatory area of left tegmen and along margins of tegmina ( Fig. 15 A, B ). Head and antennae. Antennae reddish to tawny, thick and much longer than body length. Fastigium verticis sulcate ridge, pointed at apex, with reddish lines. Thorax. Pronotal disc rounded. Body length to maximal pronotal width 5.6. Tegmina very long and slender for genus, ratio of tegmina length to width 7.6. Stridulatory file on underside of left tegmen differentiated into two parts: an inner one with densely set small teeth, separated by gap; outer part with fewer teeth increasing in size ( Fig. 16 C ). Legs. All femora in most specimens unarmed, some specimens with few very tiny spinules. Tibiae with four rows of irregular set spinules. Fore tibia in area of conchate tympana very slightly inflated. Abdomen. 10 th abdominal tergite undifferentiated, with incurved posterior margin ( Fig. 16 A ). Cerci getting gradually more slender to apex; apices of cerci slightly flattened and in-curved, tip with sclerotized small spine ( Fig. 16 A, B ). Subgenital plate broad with two broad lobes at posterior end ( Fig. 16 B ).

Female. In size and habitus very similar to male but without reddish-brown and yellow fasciae and thus more green ( Fig. 15 C ). Ovipositor long but stout, slightly curved ( Fig. 17 B ). Subgenital plate tri-angular with indentated posterior margin ( Fig. 17 A ).

Measurements, males (N = 4): Total length of body 19.6–21.6; Median length of pronotum 4.5–4.6; Length of hind femur 25.7–27.3; Length of tegmina 28.4–30.6.

Measurements, females (N = 2): Total length of body 22.0–24.0; Median length of pronotum 4.8–4.9; Length of hind femur 25.2; Length of tegmina 31.1–35.5; Ovipositor 11.7–12.6.

Diagnosis. Tenerasphaga mpwapwae n. sp. is somewhat intermediary between the two genera Lamecosoma and Tenerasphaga . The ratio body length to pronotal width (5.6) is typical for Tenerasphaga while the ratio tegmen length to width (7.6) is typical for Lamecosoma , the tegmina being very acute and slender. One generic character for Tenerasphaga are unarmed femora. However, some individuals of T. mpwapwae n. sp. have very tiny spinules ventrally on the fore and especially mid femora while some specimens investigated had unarmed femora. Molecular studies have to be applied to clarify the status of Lamecosoma and Tenerasphaga .

Distinguished from T. nanyuki Hemp, 2018 by the 10 th abdominal tergite being undifferentiated while T. nanyuki has a 10 th abdominal tergite divided into two tube-like parts and a stridulatory file with conspicuous bumps (figures in Hemp et al. 2018). T. mbulu Hemp, 2018 has a continuous stridulatory file and is stouter in its appearance compared to T. mpwapwae n. sp. A stridulatory file similar to T. mpwapwae n. sp. is found in T. chyuluensis Hemp, 2018 . However, T. chyuluensis has strongly flattened tips of the male cerci while in T. mpwapwae n. sp. the male cerci are only very slightly compressed at their tips. Further T. mpwapwae n. sp. has a very elongate appearance due to its very narrow and acute tegmina while Tenerasphaga species usually are of more stout appearance. The song of T. mpwapwae reminds strongly of the song of Horatosphaga heteromorpha (Karsch, 1889) also in terms of its loudness and thus differs very much from the monotonous or very faint songs of other Tenerasphaga species. Further Tenerasphaga species are at present all restricted to certain areas— T. bazeletae (Massa, 2017) to the Transvaal area of South Africa, T. chyuluensis to the Chyulu Hills in southern Kenya, T. mbulu to the Mbulu highlands around Mt Hanang in north-western Tanzania, T. nanyuki to the northern foothills of Mt Kenya in central Kenya, T. meruensis (Sjöstedt, 1910) to a small area between Mts Kilimanjaro and Meru in northern Tanzania, T. tenera (Hemp, 2007) to the Ngong Hills and surrounding in Kenya and T. nuda (Ragge, 1960) to the Imatong Mountains in southern Sudan.

Song. Surprisingly the song of Tenerasphaga mpwapwae n. sp. was found to be very similar to that of Horatosphaga heteromorpha (see Hemp et al. 2018). The single recorded male produced echemes with a duration of 2–3 s ( Fig. 18 ), separated by intervals of around 15 s or longer. The first part of an echeme consisted of a sequence of elements, crescending in amplitude and duration (from 70 to 120 ms; Fig. 19 ). Each element started by a loud, isolated impulse, followed by a series of impulses at intervals of 1 to 3 ms. After an interval of about 5 ms a second soft group of impulses followed, which did not show clear intervals. 20 to 30 ms later, the next element followed. Isolated by a long interval of 200 ms, the loudest element of the verse closed the unit. Sometimes two of these loud elements followed immediately one after another, as also observed in H. heteromorpha . The peak of the carrier frequency was between 15 und 20 kHz ( Fig. 20 ).

Habitat. Open grasslands.

Distribution. At present only known from the Mpwapwa plateau at around 1800 m in Central Tanzania.

Etymology. Named after the Mpwapwa plateau where this species was collected in grasslands.

Figures

FIGURE 15. Tenerasphaga mpwapwae n. sp. A, B. Male C. Female D. Apex of freshly killed male.

FIGURE 16. Morphological details of male Tenerasphaga mpwapwae n. sp. A. Rear view on male apex B. Subgenital plate C. Stridulatory file.

FIGURE 17. Morphological details of female Tenerasphaga mpwapwae n. sp. A. Subgenital plate B. Ovipositor.

FIGURE 18. Oscillograms of calling songs of Horatosphaga, Peronura and Tenerasphaga species, overview. 30-s-sections. Recording of H. leggei from Bukoba, 1–15 xi 2018, leg. Claudia Hemp.

FIGURE 19. Oscillograms of calling songs of Horatosphaga, Peronura and Tenerasphaga species, details. 4-s-sections.

FIGURE 20. Power spectra of the calling songs of the Acrometopini species studied here.