Leproscirtus granulosus ( Karsch, 1886 )

Heller, Klaus-Gerhard, Hemp, Claudia, Liu, Chunxiang & Volleth, Marianne, 2014, Taxonomic, bioacoustic and faunistic data on a collection of Tettigonioidea from Eastern Congo (Insecta: Orthoptera), Zootaxa 3785 (3), pp. 343-376 : 367-368

Leproscirtus granulosus ( Karsch, 1886)

Leproscirtus ebneri Karny, 1919 , syn. n.

Leproscirtus karschi Karny, 1919 , syn. n.

Leproscirtus granulosus aptera Karny, 1919 , syn. n.

[A] CH 4983–4 2 ♂♂, CH 4938, CH 4989, CH 4993 3 ♀♀

While the arrangement of the specimens in this genus is quite clear, the identification to species level is difficult from two reasons, from the variation of the diagnostic characters and from the definition of the species. The genus was considered as monotypic, until Karny (1919) described four new species. One of them, L. brunneri , seems to differ from all others by a double tooth on each tergite. In the same paper Karny described another new species from literature, L. griffinii , but the sole diagnostic character, the unusual length of tegmina, was obviously based on a printing error, and the species was synonymised by Ebner (1943). The remaining three species are relatively similar to each other, and differ according to the descriptions in the colour of some body parts and the shape of the male subgenital plate.

Our female specimens (habitus Fig. 13 H) agree exactly with the description of the holotype of L. granulosus Karsch (1886) (single known specimen at that time; holotype probably lost, missing in MfN at least since 1974 according to a note in the collection) having rudimentary tegmina, the tip of the ovipositor not reaching knees of hind legs (except one leg; see below) and face and other parts not bright yellow (no yellow markings mentioned in description in contrast to specimens described later (1891) by Karsch). The tegmina overlap the caudal edge of the mesonotum, longer than described for L. karschi ( Karny, 1919: p. 288) in which also the hind femora reach the tip of the ovipositor. Karny (1919), however, defines L. granulosus Karsch as having face, genae, lower edge of pronotum and mesopleura bright yellow, probably influenced by a series of specimens (from Barombi Station, Cameroun) described by Karsch (1891) which all show this character, and own new material (at least two females). According to the material in MfN, the coloration can be variable even in individuals of the same locality (yellow in 2 of 8 specimens (and in female deposited in Geneve; Hollier 2010) from Buea, Cameroun, and in 7 out of 8 specimens from Victoria, Cameroun). Only from Barombi, all specimens in MfN are yellow as noted by Karsch (1891). Karny (1919) splits the former L. granulosus in three species distinguished by the shape of the male subgenital plate and colour (yellow body parts diagnostic for ‘true’ L. granulosus ). Unfortunately, however, as mentioned above, the holotype of L. granulosus was very probably not yellow. The females of Karny’s granulosus have also clearly longer hind femora than the type (30.5–30.8 mm, type 26.8 mm, our specimens CH 4993 left side 24 (shorter), right 25 (longer than ovipositor), CH 4989 both sides 26, CH 4938 left side 25, right 24.5 mm (longer than ovipositor)). So our specimens seem to be true granulosus . Possibly Karsch (1891) and Karny (1919) assumed a second species (?) to be granulosus , which is larger (no measurements in Karsch 1891, but according to own measurements 32 mm (one female) and 27-30 mm (4 males; specimens from Barombi)) than the original species and which has bright yellow markings. Karny was aware of this possibility, however, he was erroneously asking, if Karsch’s animal from 1886 (holotype of granulosus ) might be in fact his new karschi ! The combined data from all specimens in MHB (13 males, 17 females) do not show a clear bimodality, although the yellow individuals tend to belong to the larger ones.

In the males from Cameroun, Karny (1919) distinguished three types of subgenital plates. In his ‘ ebneri ’ (some syntypes in MfN, although not mentioned by Karny as types, but same place, date and collector (Buea, 1-10th April 1891, Preuss; determined by Karsch 1892 as L. granulosus )), the median incision of the narrow subgenital plate is very short, much shorter than the lobes carrying the styli ( Fig 14 C). In ‘ karschi ’ this incision is much larger, longer than the lobes (as in Fig. 14 E, F). In Karny’s ‘ granulosus ’ the situation is intermediate ( Fig. 14 D; male from Barombi Station). In Dibongo, both types (and/or yellow and not yellow specimens) are possibly found together (same locality for both species; Karsch 1919). Our males ( Fig. 14 F; both very similar to each other) are clearly nearest to ‘ karschi ’, although they have special characters.

Instead of describing a new species, we propose to consider L. ebneri and L. karschi as synonyms of L. granulosus due to the above mentioned taxonomic problems and missing clear diagnostic characters. The high variability within Cameroun requires detailed studies throughout the range of this widespread species (see long list of references in OSF).

If the above mentioned second large and yellow species should turn out to be a good species, it must be called L. aptera Karny, 1919 . The name was coined for the missing female tegmina, but the diagnostic characteristics would be colouration and size. Otherwise aptera characterises a variety, but not a geographic subspecies.

Song. The calling song ( Fig. 15 ) consisted of isolated syllables, repeated at intervals of 10–15 s, and was heard only at night. One syllable contained ca. 35 clearly separated (im)pulses with a frequency peak at 9 kHz. We recorded two males singing closely together (in captivity). The song of the leader was followed by that of the second male usually within ca. 0.7 s and often not only by one, but by several (up to three) syllables.

The stridulatory file on the lower side of the left tegmen carries a dense series of broad teeth and ends distally in an unusual knob ( Fig. 16 A). In contrast to the upper, leather-like appearing left tegmen the lower right one presents a large transparent mirror ( Fig. 16 B).

Figures

FIGURE 13. Habitus. A— Oxyaspis congensis, active, B— Oxyaspis congensis, nearly at rest, C— Zabalius apicalis inversus, D— Pantecphylus (P.) helleri, E— Batodromeus subulo, F— Lichenochrus congicus, G— Leproscirtus granulosus ♂, H— Leproscirtus granulosus ♀, I— Karniella crassicerca, J— Plastocorypha ituriana.

FIGURE 14. A—Subgenital plate of male Lichenochrus congicus. B—Subgenital plate of male Lichenochrus marmoratus (part of photo in OSF; Source: Sweden, Stockholm, Naturhistoriska Riksmuseet (NHRS);. C-F—Subgenital plate of male Leproscirtus granulosus. C ‘ ebneri’ syntype, D ‘ granulosus’ Barombi-Station, E ‘ karschi’ Cameroun MfN _ 6194, F CH 4983; details see text. Scales 1 mm.

FIGURE 15. Oscillograms of the calling songs of pseudophylline, mecopodine and tettigoniid species (Leproscirtus granulosus two males calling; 2 s sequence).

FIGURE 16. A—Stridulatory file Leproscirtus granulosus (three-quarter view; articulation below); B—Right tegmen of Leproscirtus granulosus; C—Stridulatory file of Plastocorypha ituriana (articulation below). Scales 1 mm.