Aerotegmina megaloptera Hemp

Hemp, Claudia, 2013, Annotated list of Tettigoniidae (Orthoptera) from the East Usambara Mountains Tanzania and new Tettigoniidae species from East Africa, Zootaxa 3737 (4), pp. 301-350 : 321-322

Aerotegmina megaloptera Hemp n. sp. ( Fig. 12 A–D)

http://lsid.speciesfile.org/urn:lsid: orthoptera .speciesfile.org:TaxonName:180006

Holotype male, Tanzania, coast region Kisarawe district, Kazimzumbwi forest reserve, 39° 03´E 6° 57´S, Jan–Feb 1991, leg. FRONTIER Tanzania, depository ZMUC.

Paratypes.— 1 male nymph, last instar, same data as holotype, depository ZMUC.

Description.—Male. Colour probably green, specimens stored in alcohol. Head and antennae.—Antenna in holotype about 1.5 times as long as body length, but probably apical parts broken and thus much longer in life. Of dark colour with irregular annulate markings ( Fig. 12 A). Cuticle of head smooth. Fastigium verticis small, strongly laterally compressed, conical with acute tip. Eyes almost circular, prominent. Thorax.— Surface shining and smooth but large rugosities caused by pronotal sulci and up-lifted anterior margin of pronotum. Posterior margin strongly up-lifted ( Fig. 12 D). Acoustical chamber large and strongly inflated, closed by flap-like alae ventrally ( Fig. 12 C). Stridulatory file transverse, thickened and long, occupying almost whole anterior part of left tegmen ( Fig. 12 E). Anterior part of tegmina in the area of stridulatory file vertically raised, then strongly ballon-like rounded. Radius surrounding stridulatory area in large bow, afterwards fan-like divided into many radial side veins. These veins connected by numerous cross veins. Alae much reduced, flap-like, apically pointed, closing the acoustical chamber ventrally ( Fig. 12 C). Legs— Fore and mid femora with ventral double row of each four stout spines. Apically with a pair of short spurs. Hind femur with six small outer and three–four small inner spines, distally one spur at each side. Fore and mid tibiae with five pairs of long predatory spines at each side, apically with a pair of spurs. Hind tibiae with four rows of small spines getting denser more distally. With well developed tarsal arolium. Abdomen.— Subgenital plate symmetrical, broad and convex at apical part with smooth and shiny surface, apically divided into two stout lobes ( Fig. 12 C). Cerci strongly inflated at base, then narrowing to form slightly curved slender distal part with sclerotized tip ( Fig. 12 C).

Measurements, male (mm) (N=1). Total length of body 16. Length of pronotum 6. Length of hind femur 16.5. Length of tegmina (as seen from above) 24.

Female. Unknown.

Diagnosis.—Easily distinguished from all other described species of Aerotegmina , A. kilimandjarica Hemp, 2001 , A. shengenae Hemp, 2006 and A. taitensis Hemp, 2013 by the large size and the extremely ballon-like inflated tegmina (see Fig. 12 A, comparison with A. kilimandjarica ). A. megaloptera n. sp. shows a well developed pattern of tegminal veins while in all other Aerotegmina species the main veins are obsolete on the tegmina. The stridulatory file in A. megaloptera n. sp. is large and pronounced and the mirror on the right tegmina obsolete. In all other Aerotegmina species the stridulatory file is smaller and not as conspicuous visible on the left tegmen and on the right tegmen a large mirror is present, oval-round and hyaline. The stridulatory area is not vertically raised in the northerly distributed Aerotegmina species while in A. megaloptera n. sp. this area is almost vertically oriented ( Fig. 12 A).

Distribution: Known only from the type locality near Dar es Salaam on the Tanzanian coast but surely occurs also in other coastal forests along the coast.

Habitat: Canopy dweller in coastal forest.

Remarks: The size and shape of A. megaloptera n. sp. suggests a different evolution from the more northernly occurring Aerotegmina species of southern Kenya and northern Tanzania. It changes the picture of the evolutionary processes of this genus. From the northern species having a strikingly different morphology and also occupying a different ecological niche A. megaloptera n. sp. seems to have evolved isolated for a long geological time. A. megaloptera n. sp. is much larger than any other described species of Aerotegmina and it was collected in coastal forest while all other known species are restricted to montainous forests in the submontane and montane zones of mountains and mountain ranges. Morphologically similar is a yet undescribed species from the Udzungwa Mountains of Tanzania having the same large acoustical chamber and general habitus as A. megaloptera n. sp.

Subfamily Meconematinae

Figures

FIGURE 12. Male holotype Aerotegmina megaloptera n. sp. A. Comparison with A. kilimandjarica. B. Face. C. Ventral view on abdominal apex with spathulate alae in the backgroud. D. Lateral view on head and pronotum. E. Dorsal view on stridulatory area of left tegmen.