Revision of the tropical African genus Tetraconcha ( Orthoptera : Tettigoniidae : Phaneropterinae ) with the description of ten new species

Only five species of the genus Tetraconcha Karsch, 1890 have been previously known; they inhabit tropical forests of central and western Africa. Generally, specimens belonging to this genus are scarcely represented in museum collections, probably due to the difficulty in finding them, but also for the fragility of their body and legs. During some recent expeditions in the Central African Republic and Ivory Coast it was possible to put together an abundant amount of specimens. This allowed the present author to revise the genus and to find valid characters to distinguish different species. On the whole, ten new species were discovered and the total number now amounts to fifteen species. Interestingly, in the Dzanga-N’Doki National Park (Central African Republic) seven sister species, previously unknown, live together with T. smaragdina; it was possible to separate them by the shape and number of teeth of the stridulatory file under the left tegmen, and later other taxonomical characters were provided. This may be considered a case of evolutionary radiation; that is, Tetraconcha species in the Dzanga-N’Doki National Park evolved traits that primarily linked to sound communication. This radiation very probably occurred randomly, possibly driven by genetic drift.


Introduction
According to Ragge (1962), the genera Drepanophyllum Karsch, 1890, Stenamblyphyllum Karsch, 1896, Debrona Walker, 1870, and Tetraconcha Karsch, 1890 are a fairly well-defined group of African Phaneropterinae, in which the fore tibiae are biconchate and the fastigium of the vertex has a steeply sloping or vertical sulcus. Females have a greatly reduced ovipositor, crenulate at the tip. Actually the tribe Otiaphysini Karsch, 1889 contains only the genera Tetraconcha and Debrona, while Drepanophyllum is the only species of the Karschiae group, and Stenamblyphyllum is not listed in any tribe or group of Phaneropterinae (Cigliano et al. 2017). The genus Tetraconcha was described by Karsch (1890a) for the species T. fenestrata; in the same year Karsch (1890b) described another species, T. stichyrata. The following year, Brunner von Wattenwyl (1891) described T. smaragdina and T. scalaris: the latter was synonymized with T. stichyrata by Kirby (1906). T. stichyrata was indeed overlooked by Brunner von Wattenwyl (1891). Due to the remarkable sexual dimorphism, Bolívar (1893) erected the new genus Tellidia for the female of another new species (longipes), which Bolívar (1906) later synonymized with Tetraconcha.
The availability of a long series of specimens procured in 2005-2012 by Philippe Annoyer and Philippe Moretto from the Central African Republic provided the possibility to divide them into seven taxonomic units, vaguely similar to T. smaragdina. Specimens were collected during the night, attracted to a lamp in the same site and dates within the tropical forest of the Dzanga-N'Doki National Park. During a visit to the Naturhistorisches Museum of Vienna the type of T. smaragdina, considered probably lost (Cigliano et al. 2017), was re-discovered. This allowed the author to identify some of the specimens collected in the Central African Republic as belonging to T. smaragdina and to note that the other specimens belonged to undescribed species. Additionally, a series of other specimens of Tetraconcha collected by Marios Aristophanous, Philippe Moretto and Enrico Ruzzier for the British Museum of Natural History in the Ivory Coast in 2014-2015 was obtained on loan; this material provided another two undescribed species. Finally, during an expedition in the Taï National Park (Ivory Coast) in 2017, further specimens were collected by P. Annoyer, S. Danflous, P. Moretto and the present author: among this material another undescribed species was discovered. The high diversity of the genus, previously unrecorded, deserves particular attention. This paper deals with the known species as well as a number of new species and attempts to place them within their evolutionary context.

Material and methods
Series of specimens were obtained from Marios Aristophanous, Philippe Annoyer, Samuel Danflous, Philippe Moretto, Enrico Ruzzier and the present author; further specimens were examined from collections housed in the museums cited below.
The distribution of the genus Debrona covers the eastern and southern areas of Africa, from Tanzania and Kenya to South Africa. Drepanophyllum and Stenamblyphyllum species occur in central Africa, while Tetraconcha is restricted to central and western Africa.
Remarks.-The main characters of the genus are the following (Karsch 1890a;pers. obs.): head small, fastigium of vertex raised, tuberculated, not contiguous with fastigium of frons, sulcate, first antennal segment clearly larger than others. Eyes round, very prominent, antennae very delicate. Pronotum narrow and compressed, flat above, enlarged posteriorly, anterior margin straight, posterior margin rounded, humeral sinus rounded and deep, lateral lobes longer than high, lower margin rounded. Tegmina narrow, exceeding hind femora, anterior margin rounded, posterior margin sinuous, apex obliquely cut. Hind wings longer than tegmina. Legs very fragile and long. Fore femora compressed, lower margin armed, hind femora thin. Both inner and outer tympana of fore tibiae conchate. Cerci of male short incurved and pointed, subgenital plate more or less bilobed or pointed, styli absent. Tegmina and legs are always narrow and give to the species the long-limbed aspect. The name Tetraconcha derives from the conchate tympana (from Greek tetra = four).

Species account
Tetraconcha ruzzieri sp. n. http Color.-Head and pronotum yellow-green, abdomen brown, cerci yellow, black at the tip, tegmina green-yellow, brownish in the strid-ulatory area, with a translucent area. Fore femora brown with 4-6 black spots, mid and hind tibiae brown. One wide black spot is visible laterally on the metanotum, below the hind wing, present only in T. danflousi sp. n. This exclusive character excludes that it is the male of T. longipes, known only from the female sex, and was also collected from the Ivory Coast, along the coast next to the border with Ghana.
Description.-Males. Head and antennae: Fastigium of vertex narrow, sulcate above, separated from fastigium of frons. Eyes round-ed, well projecting. Antennae longer than body. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed on dorsal side, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 10-12 spines, fore tibiae with 4-5 spines + 1 spur on inner side and 3 small spines on anterior ventral side, 4 spines + 1 spur on outer dorsal side, mid femora armed with 5-6 spines on outer ventral side, mid tibiae with 12-13 spines on outer and inner ventral sides + 1 spur on each side, and 7 spines + 1 spur on inner dorsal side, hind femora armed with 3-4 small spines on outer side, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices, with an evident translucent area (window), laterally on the left and on the right of stridulatory areas of the left and right tegmina, respectively. Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig. 11, veinlets of left tegmen in Fig. 99; stridulatory file arched and interrupted at the mid by a bulge, the half whitish proximal part composed of ca. 80 very dense and evenly spaced teeth, the central brown part (including also the bulge) composed of ca. 30 widely spaced teeth, and the distal brown part composed of ca. 80-90 dense and evenly spaced teeth (Fig. 12). Abdomen: Subgenital plate with a well-developed concavity, cerci slender, fairly straight and incurved at the tip (Figs 13-14).
Measurements.-Cf. Tables 1 and 2. Diagnosis.-T. ruzzieri sp. n. seems to be related to T. fenestrata, but its windows (translucent areas) on the tegmina are differently placed, like all veinlets (compare Figs 69,71,99). Different between males of the two species are also the subgenital plates, the stridulatory files and cerci. It is also related to T. danflousi sp. n., which has only one small window on the tegmina and a clear concavity between the stridulatory file and the rest of the tegmina.
Etymology.-This species is named after Enrico Ruzzier, who, together with M. Aristophanous and P. Moretto, collected many specimens of Orthoptera in the Ivory Coast by means of light traps in 2015; the material caught was sent on loan to the present author. Remarks.-T. fenestrata is the type species of the genus Tetraconcha.
The ratio length/width tegmina in males is between 3.5 and 3.6, in females it is between 2.6 and 3.4 (Bolívar 1906;present study). Kirby (1906) cited it from Ivory Coast, Bolívar (1906) described the female. Griffini (1906) cited 1♂ from Fernando Póo, and later Griffini (1908) described the female and recorded 3♂ and 8♀ from Cameroon. Sjöstedt (1912) recorded 3♀ from Buea (Cameroon). The name fenestrata refers to the wide translucent area (from Latin fenestra = window) on the tegmina. The stridulatory area of left and right tegmina are shown in Fig. 15; stridulatory file arched and interrupted before the proximal end by a bulge, followed by ca. 15 teeth decreasing in size, distal part (including also the bulge) is composed of ca. 35 widely spaced teeth (Fig. 16), subgenital plate with a narrow concavity, cerci stout and incurved at the tip (Figs 17-18).
1.3 2.9-3.8 0.4-0.5, 0.2-0.5 T. omonomai sp. n.  Color.-Head and pronotum yellow-green, abdomen yellowbrown, cerci brown, tegmina green with black spots on the anterior margin and along the diagonal veinlets. A translucent area at the base of tegmina. Like T. ruzzieri sp. n., one wide black spot is visible laterally on the metanotum, below the hind wing. This conspicuous character allows to exclude it as male of T. longipes, known only from the female sex, also collected in the Ivory Coast, along the coast next to the border with Ghana.
Description.-Male. Head and antennae: Fastigium of vertex flat and sulcate, separated from the fastigium of frons. Eyes rounded, well-projecting. Antennae longer than body. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed above, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 9 spines, fore tibiae with 7 spines + 1 spur on both ventral sides, 7 spines + 1 spur on outer dorsal side, mid femora armed with 8 spines on anterior ventral side, mid tibiae with 25-26 spines on both ventral sides + 1 spur on each side, and 9 spines + 1 spur on inner dorsal side. Hind femora unarmed, hind tibiae with many spines on both dorsal and ventral sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lateral lobes rounded. Tegmina narrow with rounded apices. Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig. 19, characterised by a protruding stridulatory file at the base of the left tegmina, separated by the rest of wing by a concavity (see arrow in Fig. 19) and a translucent area on both bases of tegmina ( Fig. 19) that replaces the cubital areas. Stridulatory file curved, ca. 1.0 mm long, composed by ca. 100 very dense and evenly spaced teeth (Fig. 20). Abdomen: Subgenital plate with a "V"-shaped concavity, cerci stout and incurved (Figs 21-22). Female. Unknown.
Diagnosis.-T. danflousi sp. n. may be easily recognised by its translucent area at the base of tegmina, by protruding stridulatory area and a well-developed concavity between the stridulatory area and the rest of the left tegmen (Fig. 19) , the high number of spines on mid tibiae.  Remarks.-When Karsch (1891) established the synonymy of T. scalaris from Gabon with T. stichyrata, he also briefly described the female of T. stichyrata, and gave its measurements, including the length (31.5 mm) and width (10 mm) of tegmina; however, according to Karsch (1891) the ratio length/width of tegmina in the males of this species should be 3.1, but it actually varies between 3.0 and 4.6, while in the females it lies between 4.0 and 4.8.
Journal of orthoptera research 2017, 26(2) The stridulatory area and stridulatory file of T. stichyrata are shown in Figs 23-24; the stridulatory file is ca. 1.7 mm long, curved and consists of ca. 60 evenly spaced teeth; cubital areas are very wide (Fig. 24). The subgenital plate of this species is completely different from that of all other species of the genus being apically pointed not concave (Fig. 25). T. stichyrata has tegmina comparatively shorter than other species of the genus, so that the hind wings, when closed, remarkably exceeds the tegmina, both in males and in females.
Distribution.-T. stichyrata has been recorded in Cameroon and Gabon; it is here reported from Ivory Coast. Very probably its distribution covers central and western regions of tropical Africa. Remarks and distribution.-Only the female is known from Assinie (Ivory Coast) (Bolívar 1893(Bolívar , 1906. The ratio length/width of tegmina is 3.4. Chopard (1954) also recorded one female from Mt. Nimba (Ivory Coast). However, since now new species are recorded from Ivory Coast it is doubtful that the specimen from Mt Nimba is conspecific with T. longipes (see section on female characters). According to Bolívar (1893) this species has small blackish spots along the veinlets of tegmina and the ovipositor is 2.5 mm long. Griffini, 1909 http://lsid.speciesfile.org/urn:lsid:Orthoptera.speciesfile. Remarks.-When Griffini (1909) described T. banzyvilliana on a female, he established to include the species of Tetraconcha with long and thin legs to the subgenus Tellidia. However, only after the description of the genus Tellidia (Bolívar, 1893), Bolívar (1906) realized that it was synonymous with Tetraconcha, represented by species characterised by very long legs (see Table 2). Thus, the subgenus Tellidia has to be considered definitely synonymous with Tetraconcha. Leroy (1970)

Tetraconcha banzyvilliana
The stridulatory area is reported in Fig. 26. We know the pattern of the stridulatory file, thanks to the short and interesting note by Leroy (1970) photographing the structure with a SEM; it is curved and characterized by a proximal part with many dense and evenly spaced teeth and a distal part with few widely spaced teeth (Fig. 27), similar to that of T. perezi sp. n. Ratio length/width tegmina in females is 6.5.
Color.-Head, antennae, pronotum and abdomen brown, face with a yellow spot, cerci yellow, tegmina with a black spot at their base, brown with yellow veinlets, bright yellow in the stridulatory area. Femora yellow-brown or green-brown (Figs 73, 96).
Description.-Males. Head and antennae: Fastigium of vertex tuberculated, narrow, separated from fastigium of frons, little sulcate. Eyes rounded, well projecting. Antennae longer than body, exceeding hind femora, first segment well developed, comparatively to the other species of the genus. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed dorsally, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 6-7 spines, fore tibiae with 6-7 spines + 1 spur on inner ventral side and 6 small spines on outer ventral side, 5 spines + 1 spur on outer dorsal side, mid femora armed with 6-7 spines on outer ventral margin, mid tibiae with 15-17 spines on outer and inner ventral sides + 1 spur on each side, and 3 spines + 1 spur on inner dorsal side, hind femora armed with 1-2 small spines on outer and inner ventral sides, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin straight, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices. Cubital area of the left tegmen narrow (Table 1). Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig. 28; stridulatory file strongly curved and interrupted in the mid section by a bulge, followed by ca. 40 evenly spaced teeth, the distal part is composed of ca. another 40 widely spaced teeth (Fig. 29). Abdomen: Subgenital plate with a very small concavity, cerci stout and much incurved at the tip (Figs 30-31).
Diagnosis.-T. perezi sp. n. is very characteristic for the narrow fastigium of the vertex, the bright yellow stridulatory area, the subgenital plate with a very small concavity, cerci stout and strongly incurved, and the uniform brown color. Journal of orthoptera research 2017, 26 (2) The 'smaragdina-group' Redescription.-Males. Head and antennae: Fastigium of vertex narrow, sulcate above, separated from fastigium of frons, furrowed. Eyes rounded, well projecting. Antennae longer than body. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed dorsally, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 7-10 spines, fore tibiae with 6-7 spines + 1 spur on inner side and 3-4 small spines on outer ventral side, 3 spines + 1 spur on outer dorsal side, mid femora armed with 7-8 spines on outer ventral side, mid tibiae with 12-13 spines on outer and inner ventral sides + 1 spur on each side, and 3 spines + 1 spur on inner dorsal side, hind femora armed with 2-5 small spines on the outer [Brunner von Wattenwyl (1891) recorded 5 spines] and 1-2 on inner ventral sides, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices. Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Figs 32-33, veinlets of left tegmen in Fig. 88; stridulatory file arched and composed of ca. 65-70 dense and evenly spaced teeth plus 3-4 widely spaced teeth in the distal part (Fig. 34). Abdomen: Subgenital plate long and apically narrowed with a narrow concavity protruding beyond cerci, and two longitudinal carinae on the sides; cerci stout at their base and incurved (Figs 35-36).
Female. Bolívar (1906) described the female, but considering the presence and the co-occurrence of more than one species of the 'smaragdina-group', the description cannot be considered to belong to T. smaragdina for certain. One female collected in Cameroon (Mukonje Farm) and dubiously reported by Griffini (1908) as T. smaragdina, very probably belongs to this species. The ratio length/width of tegmina in the specimen cited by Griffini (1908) is 4.6 (Fig. 84).
Diagnosis.-Characters of T. smaragdina are: stridulatory area of left and right tegmina and stridulatory file as in Figs 32-33 and 34, subgenital plate of male long and narrow with two parallel longitudinal keels, ending with a narrow concavity, protruding beyond cerci, when viewed from above (Fig. 35).
Measurements.-Cf. Tables 1 and 2. Distribution.-T. smaragdina is present in Cameroon, the Democratic Republic of Congo and Central African Republic; according to Ragge (1967) very probably its distribution covers all Central Africa from Democratic Republic of Congo to Liberia, but in the present paper the high diversity of the 'smaragdina group' is shown, and many records from some countries possibly have to be referred to other species.

Tetraconcha loubesi sp. n.
http://lsid.speciesfile.org/urn:lsid:Orthoptera.speciesfile. Color.-Head and pronotum yellow-green, abdomen yellowbrown, cerci yellow, tegmina with a black spot at their base, green with black spots on back veinlets, brownish in the stridulatory area. Description.-Males. Head and antennae: Fastigium of vertex narrow, sulcate above, separated from fastigium of frons. Eyes rounded, well projecting. Antennae longer than body. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed dorsally, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 9-10 spines, fore tibiae with 6-7 spines + 1 spur on inner side and 3-4 small spines on outer ventral side, 2 spines + 1 spur on outer dorsal side, mid femora armed with 7-8 spines on outer ventral side, mid tibiae with 15-17 spines on outer and inner ventral sides + 1 spur on each side, and 3 spines + 1 spur on inner dorsal side, hind femora armed with 5-6 small spines on outer and 1-2 on inner ventral sides, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices. Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig.  37, veinlets of left tegmen in Fig. 89; stridulatory file arched and composed of ca. 100 very dense and evenly spaced teeth plus 7-8 widely spaced teeth in the distal part, followed by ca. 6-7 very small and little raised teeth (Fig. 38) Color.-Head and pronotum yellow-green, abdomen yellowbrown, cerci black, tegmina with a black spot at their base, green with black spots on veinlets, in most specimens the stridulatory area is brown (Fig. 41).
Description.-Males. Head and antennae: Fastigium of vertex narrow, sulcate above, separated from fastigium of frons. Eyes rounded, well projecting. Antennae longer than body. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed on upper margin, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 10-12 spines, fore tibiae with 5 spines + 1 spur on inner side and 2 spines on outer ventral side, 2 spines + 1 spur on outer dorsal side, mid femora armed with 7-8 spines on outer ventral side, mid tibiae with 10-12 spines on outer and inner ventral sides + 1 spur on each side, and 3 spines + 1 spur on inner dorsal side, hind femora armed with 5-6 small spines on outer and 1-2 on inner ventral sides, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices. Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig. 41, veinlets of left tegmen in Fig. 90; stridulatory file arched and composed by ca. 20 very dense, little raised and evenly spaced teeth in the proximal part (ca. 1/3 of the length), and ca. 14-15 widely spaced teeth in the distal part (ca. 2/3 of the length) (Fig. 42) Abdomen: Subgenital plate large and short with a fairly developed concavity, cerci slender, fairly straight and incurved at the tip (Figs 43-44). Female (Fig. 85). A female was collected together with some males. It has the same characters of the male except of the following: The color of the fore legs, mid tibiae and first antennal segments are blackish, tegmina green with brownish veinlets. Fore femora with 6 spines, mid femora with 8 spines and hind femora with 4 spines. The ovipositor is very short (2.5 mm).
Etymology.-This species is gratefully named after the French colleague Philippe Moretto, who collected a long series of specimens of Tetraconcha and other interesting species from the Central African Republic and the Ivory Coast. Color.-Head and pronotum yellow-green, abdomen yellowbrown, tegmina with a black spot at their base, green with yellow spots between veinlets.
Description.-Males. Head and antennae: Fastigium of vertex narrow, sulcate dorsally, separated from fastigium of frons. Eyes rounded, well projecting. Antennae long. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed on upper margin, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 6-7 spines, fore tibiae with 4-5 spines + 1 spur on inner side and 3 spines on outer ventral side, 3 spines + 1 spur on outer dorsal side, mid femora armed with 6-7 spines on outer ventral side, mid tibiae with 15-16 spines on outer and inner ventral sides + 1 spur on each side, and 4 spines + 1 spur on inner dorsal side, hind femora armed with 6-7 small spines on outer and 1-2 on inner ventral sides, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices. Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig. 45, veinlets of left tegmen in Fig. 94; stridulatory file curved and composed of ca. 30 very dense and evenly spaced teeth in the proximal part (ca. ¼ of the length), and 8-10 widely spaced teeth in the distal part (ca. ¾ of the length) (Fig. 46). Abdomen: Subgenital plate short with a little concavity, cerci slender and incurved (Figs 47-48).
Color.-The whole body yellowish, tegmina with a black spot at the base, many yellowish or whitish spots between veinlets; black spots along the veinlets of posterior area of tegmina; ventral side of hind femora generally brownish.
Description.-Males. Head and antennae: Fastigium of vertex narrow, sulcate above, separated from fastigium of frons. Eyes rounded, well projecting. Antennae long. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed dorsally, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 7-8 spines, fore tibiae with 5-6 spines + 1 spur on inner and on outer ventral sides, 3 spines + 1 spur on outer dorsal side, mid femora armed with 8-9 spines on outer ventral side, mid tibiae with 15-16 spines on outer and inner ventral sides + 1 spur on each side, and 4-5 spines + 1 spur on inner dorsal side, hind femora armed with 6 small spines on outer and 3 on inner ventral sides, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices. Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig. 49, veinlets of left tegmen in Fig. 91; stridulatory file arched and composed by ca. 100 very dense and evenly spaced teeth in the proximal part (ca. 1/3 of the length), and 15 widely spaced teeth in the distal part (ca. 2/3 of the length) (Fig. 50). Abdomen: Subgenital plate short with a wide concavity, cerci slender and incurved (Figs 51-52).
Etymology.-This species is named after Philippe Annoyer, President of the Association Insectes du Monde and organizer of the expedition Sangha 2012; he also collected many interesting Orthoptera during the expedition to the Taï Forest (Ivory Coast) in 2017.
Distribution.-Known only from Central African Republic. Color.-Head and pronotum yellow-green, abdomen yellowbrown, tegmina with a black spot at their base, green with yellow spots between veinlets.
Description.-Males. Head and antennae: Fastigium of vertex narrow, sulcate above, separated from fastigium of frons. Eyes rounded, well projecting. Antennae long. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed dorsally, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 8-9 spines, fore tibiae with 4-5 spines + 1 spur on inner and on outer ventral sides, 2-3 spines + 1 spur on outer dorsal side, mid femora armed with 5 spines on outer ventral side, mid tibiae with 13 spines on outer and inner ventral sides + 1 spur on each side, and 4 spines + 1 spur on inner dorsal side, hind femora armed with 5 small spines on outer ventral side, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices. Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig. 53, veinlets of left tegmen in Fig. 92; stridulatory file angularly arched and composed of ca. 120 very dense and evenly spaced teeth in the proximal part (ca. 2/3 of the length), and 6 widely spaced teeth in the distal part (ca. 1/3 of the length) (Fig.  54). Abdomen: Subgenital plate short with a little concavity, its appendices close together, cerci stout and incurved (Figs 55-56). Female. Unknown.
Diagnosis.-T. fijalkowskii sp. n. is characterised mainly by the presence of yellow spots on tegmina (Fig. 92), its stridulatory area of the left and right tegmina (Fig. 53), its peculiar stridulatory file (Fig. 54), its subgenital plate with narrow appendices (Figs 55-56). Note also the short size of the hind femur.  Color.-Head and pronotum yellow-green, abdomen yellowbrown, tegmina with a black spot at their base, green.
Description.-Males. Head and antennae: Fastigium of vertex narrow, sulcate above, separated from fastigium of frons. Eyes rounded, well projecting. Antennae long. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed dorsally, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 4-5 spines, fore tibiae with 4-5 spines + 1 spur on inner and on outer ventral sides, 3 spines + 1 spur on outer dorsal side, mid femora armed with 6-7 spines on outer ventral side, mid tibiae with 7-9 spines on outer and inner ventral sides + 1 spur on each side, and 4 spines + 1 spur on inner dorsal side, hind femora Journal of orthoptera research 2017, 26 (2) armed with 6-7 small spines on outer ventral side, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices. Compared to other species of the "smaragdina-group" cubital area between cubitus of the left tegmen narrower (Table 1). Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig. 57, veinlets of left tegmen in Fig. 93; stridulatory file arched and composed by ca. 30 very dense and evenly spaced teeth in the distal part (ca. ¼ of the length), ca. 15 widely spaced teeth in the central part (ca. 2/4 of the length), and ca. 10 dense and evenly spaced teeth in the proximal part (ca. ¼ of the length) (Fig. 58). Abdomen: Subgenital plate long with a wide concavity, cerci slender, fairly straight and incurved at the tip (Figs 59-60). Female. Unknown.
Etymology.-This species is named after Dieu béni Bongola Omonoma, local collector of insects within the forest during the expedition Sangha 2012. Color.-Head and pronotum green-brown, abdomen brown, tegmina green with some yellow spots between veinlets, abdomen brown, cerci brown.
Description.-Males. Head and antennae: Fastigium of vertex narrow, sulcate above, separated from fastigium of frons. Eyes round-ed, well projecting. Antennae long. Legs: Fore coxae armed with a small spine. Fore tibiae furrowed dorsally, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 13-14 spines, fore tibiae with 6 spines + 1 spur on inner and on outer ventral sides, 1-3 spines + 1 spur on outer dorsal side, mid femora armed with 10-12 spines on outer ventral side, mid tibiae with 14-15 spines on outer and inner ventral sides + 1 spur on each side, and 3-4 spines + 1 spur on inner dorsal side, hind femora armed with 7-8 small spines on outer and 1-2 on inner ventral sides, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Thorax: Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Tegmina narrow with rounded apices. Wings longer than tegmina. Stridulatory area of left and right tegmina shown in Fig. 61, veinlets of left tegmen in Fig. 95; stridulatory file arched and composed of ca. 100 teeth, 75-80 dense and evenly spaced teeth in the proximal half, and ca. 20-22 widely spaced teeth in the distal half (Fig. 62). Abdomen: Subgenital plate long and with a more or less narrow and deep concavity, cerci stout, fairly straight and incurved at the tip (Figs 63-64).
Female. Two females collected in the same area with some males (Mt. Tonkoui and Taï Nat. Park, Res. Station) were available, and it is also possible to describe this sex, which resulted to be clearly different from T. longipes (compare Figs 82 and 83), also described from the Ivory Coast, along the coast next to the border with Ghana. Same characters of the male, with the following differences: Body stout, tegmina wider than in males (see Table  2), tubercle of frons much smaller, and mandibles stouter than in males (Figs 65-66). Coxae armed with a very small spine. Femora brown, some black spots between posterior veinlets of tegmina, 4 big spines on lower side of fore and mid femora, 6 on hind femora. Ovipositor short (2.5 mm) and crenulated at the tip of lower valve. The ratio length/width of tegmina is 3.3.
Diagnosis.-T. aristophanousi is characterised by its stridulatory area, stridulatory file (Figs 61, 62) and the subgenital plate, long and with a more or less narrow and deep concavity, cerci are stout basally (Figs 63, 64).
Etymology.-This species is dedicated to Marios Aristophanous, who, together with P. Moretto and E. Ruzzier collected in the Ivory Coast with a light trap many specimens of Orthoptera and made them available to the author.
Distribution.-T. aristophanousi is known from Ivory Coast and Sierra Leone; it probably covers other intermediate western African countries.

Characters of females of the genus Tetraconcha (Figs 79-85)
Females may be separated by the ratio length/width of tegmina, lying between 2.6 and 3.4 in T. fenestrata, 3.3 in T. aristophanousi sp. n., 3.4 in T. longipes, between 4.0 and 4.8 in T. stichyrata, 5.0 in T. morettoi sp. n., 6.5 in T. banzyvilliana. In T. smaragdina, according to Bolívar (1906), the ratio length/width tegmina in a female from Cameroon was 2.5, in another 4.5, but since now more new species belonging to the "smaragdina-group" were discovered, it is unlikely that the female described by him belongs to T. smaragdina or to another new species of the group. In addition, there are 3-4 diagonal veinlets with small brownish spots in T. fenestrata and in T. aristophanousi sp. n., a net of veinlets with black spots in T. stichyrata, a very singular color in T. banzyvilliana, while in T. longipes the pattern of black spots in the tegmina is very similar to that of T. stichyrata.
The genus Tetraconcha is known for its high sexual dimorphism. It has not been previously mentioned that males and females differ considerably by the size of the tubercles on the frons (smaller in females) and the larger size of the mandibles in females; e.g. in T. aristophanousi sp. n. the maximum width of female mandible is 0.8, while in the male it is 0.4 mm (Fig. 83). Probably, the size of the mandibles depends on the females need to open hard vegetal tissues into which they can insert the very short ovipositor to lay eggs.
The eggs of Tetraconcha are similar to those of the genus Phlaurocentrum Karsch, 1889(Massa 2013. In difference to the majority of the other genera, eggs of Tetraconcha and Phlaurocentrum are not flat, but, even if oval, they are fairly round and thick. The morphology of eggs suggests a high resistance to desiccation (very thick chorionic layers that reduce the rate of water loss). Additionally, the valvules of the ovipositor are not laterally flattened, which indicates that the eggs are not inserted between the layers of the leaf epidermis. This is possibly due to the fact that they lay their eggs in clusters between cracks of tree bark.
Key to males of species of the genus Tetraconcha Karsch, 1890 (cf. also Tables 1 and 2).
T. longipes (Bolívar, 1893) is not included, being known only from the female sex) 1 Tegmina with a translucent area (

Concluding remarks on the evolutionary radiation of Tetraconcha
Tetraconcha species are certainly not an iconic group, like Darwin's finches of the Galápagos or the Cichlids of Lake Victoria (cf. Soulebeau et al. 2015), and their biology is fairly unknown. However, that of Tetraconcha is a case of multiple speciation, not in islands or lake systems, but within a tropical forest ecosystem. The emergence of many species from a common ancestor and the phenotypic diversification within the same environment deserve discussion. Evolutionary radiation is comparatively poorly studied in tropical rainforests of Central Africa, because the local biodiversity has been little documented (Soulebeau et al. 2015 (Massa 2013, 2015, 2016, Hemp and Massa 2017. Also other groups of insects have representatives in this protected forest area and species of different orders have the specific name ndokiensis or ndoki (e.g. Tortorici et al. 2016). This demonstrates directly the high local biodiversity and indirectly the high variety of habitats. Thus, similar groups of insects evolved in similar environments, possibly promoted by similar local factors stimulating adaptation.
Concerning Tetraconcha, the increase in morphological disparity and taxonomic diversity in the 'smaragdina group' is very likely the effect of an evolutionary radiation, which may depend on 'adaptive' changes to micro-habitats within the wide tropical forest environment of central Africa. Seven species here treated were collected with the aid of a lamp in the same site and dates and certainly live close by. They may occupy different ecological niches (possibly different layers of vegetation), but live in the same forest site (Fig. 101) and have the same phenology, co-occurring and being active in January-March. In addition, three further undescribed species live together in the Ivory Coast, and probably a deeper examination of specimens preserved in Natural History Museums will result in the discovery of further undescribed species. One of the morphological characters observed to discriminate the above cited species is the stridulatory system: in these taxa, differences in the shape and number of teeth of stridulatory system result in a different sound, which in most Orthoptera is a very important species-specific barrier (Heller 2006).
Has the emergence of many new species from a common ancestor, occurred in sympatry, accompanied by an ecological and phenotypic diversification? Phenotypic diversity of Tetraconcha species was very likely linked to ecological diversity of the African tropical forest, and potential selective pressures might have promoted the speciation through their isolation. The potential selective pressures that could have promoted such strikingly high level of speciation are unknown, and the existence of any adaptation supposedly driving the radiation has not been tested. The necessary test in this case should be to find a pattern of ecomorphological divergence demonstrating that phenotypes and ecology are closely related (cf. Lieberman 2012), but this information is not available. However, African Phaneropterinae lie within a taxonomic group that has a great propensity to speciate.
According to Simões et al. (2016) there are various types of evolutionary radiation. Very probably, the genus Tetraconcha has undergone geographic radiation in Central and West Africa (allopatric speciation). Conversely, the case occurred in the Dzanga-N'Doki National Park is more difficult to understand. Tropical forest canopy is known as one of the most diversified environments, holding many ecological niches, where numerous species of insects and other animals adapted and evolved (Malhi et al. 2013). Some of them only live in well-defined layers of vegetation and only by chance that they may be detected during entomological researches (e.g. attracted by light during the night).
Thus, if we consider the ecological differences in the forest canopy of Central Africa, speciation may have occurred in Tetraconcha species both by adaptive and exaptive radiation, sensu Soulebeau et al. (2015) and Simões et al. (2016). According to Simões et al. (2016), adaptive radiation is the increase in the rate of speciation driven primarily by biotic factors in the form of adaptations associated both with ecological and morphological roles of individuals involved. Conversely, exaptive radiation is the increase in the rate of speciation driven by a previously acquired trait becoming advantageous under a new selective regime. Tetraconcha species in the Dzanga-N'Doki National Park evolved traits primarily linked to the sound communication and this very probably occurred when a selective regime was established. Changes in this kind of phenotypic trait through time may have occurred randomly, possibly driven by genetic drift. However, sound traits play an important role in the isolation and evolutionary radiation (Heller 2006); thus, the exaptive, more likely than adaptive radiation, has occurred in the case of the Dzanga-N'Doki Tetraconcha species.
Finally, a climatic radiation may have co-occurred, at least for some of the species involved. Tropical forest region of Central and West Africa, also termed Guineo-Congolian region, is the second largest tropical forest of the world, with 89.3% of the total forest surface in Central and 6.0% in West Africa (Malhi et al. 2013). According to Maley (1996) African rainforests retreated during dry periods, with slow-dispersed species, expanding slowly out of refugia. The rapid climate fluctuations after the Ice Age (between 11000 and 4000 years BP) would have favoured the dispersion of species. The climate of tropical Africa following the Ice Age was warmer and wetter than present (African humid period: Willis et al. 2013). The climate in most Central Africa shifted to a drier regime between 4000 and 2000 years BP, when the forest cover retreated (Willis et al. 2013). Climatic radiation is a type of geographic radiation in which allopatric speciation in the region is driven by changes in climate (Simões et al. 2016). Speciation events are often correlated with humid and dry periods; forest expansion during humid periods and retraction during dry periods are considered the best explanation Journal of orthoptera research 2017, 26 (2) for the patterns of geographical species distribution found on East African mountains (Schultz et al. 2007, Hemp et al. 2015. Thus, following the above reported reconstruction, we may hypothesize that in the area of Dzanga-N'Doki tropical forest the ancestor of 'smaragdina-group' could have remained isolated in patches of forest during a dry period and derived populations could have met each other when the climate shifted to a warmer regime (African humid period). They could have undergone multiple episodes of allopatric speciation, more probably than of sympatric radiation (Lieberman 2012). Bioacoustic differences allowed them to remain separated.