Revision of the Afrotropical genus Leiodontocercus (Orthoptera, Tettigoniidae, Phaneropterinae) with a description of four new species

Abstract

Specimens belonging to the genus Leiodontocercus are rare or even absent in natural history museum collections; this is likely due to at least two reasons, notably, their relatively small size, and, the sheer difficulty in finding them in dense Afrotropical forests. Until recently, three species from less than fifteen specimens were known from this genus, whose identification relied on a singular diagnostic character, that is, the shape of the male cerci. The present contribution is based on the examination of thirty specimens collected from various countries, ranging from central to west Africa; apart from the male cerci, a second diagnostic character – the stridulatory file – is used to distinguish species, even though it is difficult to examine in mounted specimens. As a result, four new species were detected, namely, L. vicii sp. nov. , L. spinicercatus sp. nov. (from the Central African Republic), L. muticus sp. nov. (from Gabon and Cameroon) and L. philipporum sp. nov. (from Côte d’Ivoire). Moreover, L. condylus is recorded from the Central African Republic, the only country where three species of this genus co-occur. It is suggested that population isolation during fluctuating humid and dry periods, consequent to the influence of Ice Age impact during the Pleistocene in tropical central Africa, is the best explanation for the adaptive radiation of the group.

Full text

Revision of the Afrotropical genus Leiodontocercus
(Orthoptera, Tettigoniidae, Phaneropterinae) with a
description of four new species
Bruno Massa1
1 Department of Agriculture, Food and Forest Sciences, University of Palermo, Italy
Corresponding author: Bruno Massa (bruno.massa@unipa.it)
Academic editor: Tony Robillard |  Received 30 April 2020  |  Accepted 9 June 2020|Published 22 July 2020
http://zoobank.org/96D4ECCD-ECAB-4942-9FE5-FB55D6D1C7B3
Citation: Massa B (2020) Revision of the Afrotropical genus Leiodontocercus (Orthoptera, Tettigoniidae, Phaneropterinae)
with a description of four new species. ZooKeys 951: 47–65. https://doi.org/10.3897/zookeys.951.53814
Abstract
Specimens belonging to the genus Leiodontocercus are rare or even absent in natural history museum col-
lections; this is likely due to at least two reasons, notably, their relatively small size, and, the sheer diculty
in nding them in dense Afrotropical forests. Until recently, three species from less than fteen specimens
were known from this genus, whose identication relied on a singular diagnostic character, that is, the
shape of the male cerci. e present contribution is based on the examination of thirty specimens collected
from various countries, ranging from central to west Africa; apart from the male cerci, a second diagnostic
character – the stridulatory le – is used to distinguish species, even though it is dicult to examine in
mounted specimens. As a result, four new species were detected, namely, L. vicii sp. nov., L. spinicercatus
sp. nov. (from the Central African Republic), L. muticus sp. nov. (from Gabon and Cameroon) and
L.philipporum sp. nov. (from Côte d’Ivoire). Moreover, L. condylus is recorded from the Central African
Republic, the only country where three species of this genus co-occur. It is suggested that population
isolation during uctuating humid and dry periods, consequent to the inuence of Ice Age impact during
the Pleistocene in tropical central Africa, is the best explanation for the adaptive radiation of the group.
Keywords
Central and West Africa, leaf katydids, new species, speciation, taxonomy
ZooKeys 951: 47–65 (2020)
doi: 10.3897/zookeys.951.53814
https://zookeys.pensoft.net
Copyright Bruno Massa. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
RESEARCH ARTICLE
Launched to accelerate biodiversity research
A peer-reviewed open-access journal

Bruno Massa / ZooKeys 951: 47–65 (2020)
48
Introduction
e genus Leiodontocercus was described by Chopard (1954) together with its type-
species L. angustipennis from Mt. Nimba (Guinea, tropical Africa). Ragge (1962), sub-
sequently revised the genera of the tribe Phlaurocentrini Karsch, 1889, describing two
new species within this genus, L. condylus from the Democratic Republic of Congo
and L. malleus from Ghana; Ragge’s new descriptions were based on the shape of the
male cerci. Since these initial works, very few specimens were studied: Chopard (1954)
examined only one specimen, Ragge (1962) studied a further 12 specimens, while
Massa (2013) examined another seven specimens, recorded from the Central African
Republic; nally, Massa et al. (2020) listed 21 specimens. e present author studied
a total of 30 specimens for this revision, most of which were collected during dierent
entomological expeditions to the Côte d’Ivoire, Central African Republic, Cameroon
and Gabon, respectively.
Material and methods
e species currently grouped in Leiodontocercus were, until recently, recognized only
by the shape of the male cerci; no other characters have hitherto been known or pro-
posed to separate the species. In this paper, the stridulatory le under the male’s left
forewing and the associated number and arrangement of teeth have been used as di-
agnostic characters. ey are useful characters that determine whether species are bio-
acoustically separated from another one (Ragge 1980, Heller 2006).
Specimens studied for this contribution were collected at night time, attracted
to a light trap (UV) that was set up both on the ground and in the canopy (35
to 55 meters high) in central-western countries of tropical Africa (Côte d’Ivoire,
Gabon, Cameroon and the Central African Republic). Before mounting the speci-
mens, the left wing of every male characterized by dierent cerci was spread in
a manner that allowed a clear examination of the stridulatory le under the fore
wing. Some specimens were dissected to inspect organs as well as to extract eggs
from female specimens. Characters of specimens, stridulatory area, stridulatory
le, cerci in frontal and lateral views were photographed with a Nikon Coolpix
4500 digital camera, mounted on a Wild M3 Stereomicroscope. Photographs were
integrated using the freeware CombineZP (Hadley 2008). Mounted specimens
were measured with a digital caliper (precision 0.01 mm); the following measure-
ments were taken (in mm): body length: dorsal length from the head to the apex of
the abdomen; pronotum length and height; tegmina: length and maximum width;
hind femora length.
In view of the diculty to distinguish between females of dierent species, in the
present paper they are listed together with male specimens that were collected in the
same locality and on the same date. For the same reason, no females are listed within
the paratypes of new species, but merely as material examined. us, the description of
female characters is reported within that of the genus.

African Leiodontocercus and its species 49
Abbreviations used in this paper
ANHRT African Natural History Research Trust, Hereford, UK;
BMPC Bruno Massa Private Collection, Palermo, Italy;
MNHN Muséum National d’Histoire Naturelle, Paris, France;
MSNP Museo di Storia Naturale, University of Pavia, Italy;
NHW Naturhistorisches Museum Wien, Vienna, Austria;
PAPC Philippe Annoyer Private Collection, Sainte Croix Volvestre, France.
Results
Characters of Leiodontocercus Chopard, 1954 (species-type: L. angustipennis
Chopard, 1954)
e word Leiodontocercus derives from the Greek and means “cercus with a smooth tooth”
(λέιος = smooth, ὀδόντος genitive of ὀδούς = tooth). Leiodontocercus is characterized by a
strongly compressed fastigium of vertex which slopes to the frons and is sulcate above; teg-
mina are very narrow, obliquely truncate apically; male last sternite without styli, and cerci
stout and enlarged apically. Like in the other Phlaurocentrini, the 10th abdominal tergite
of the female is hood-like and conceals the supra-anal plate; the ovipositor is very similar
to that of Buettneria Karsch, 1889, it is much reduced and with smooth and short valves.
Ventral valves are short, upward and apically pointed, dorsal valves longer than ventral ones,
straight like two short ngers; the subgenital plate of the female lacks diagnostic characters,
in all specimens examined it is triangular with a central ne keel (Figs 1–3). us, like in the
other genera of the tribe Phlaurocentrini the valves of the ovipositor are not attened later-
ally. is indicates that the eggs are not inserted between the layers of the leaf epidermis, as
in most Phaneropterinae, but possibly they are laid between cracks of tree bark. e eggs of
Leiodontocercus species are not at, like most species of Phaneropterinae, but nearly round
and thick, similarly to species of Phlaurocentrum Karsch, 1889. Very likely this shape con-
veys a high resistance to desiccation (very thick chorionic layers that reduce the rate of water
loss). e number of eggs found within the female oviduct was low (between 10 and 15).
Annotated list of species
Leiodontocercus angustipennis Chopard, 1954
Figs 14, 16, 16a
Leiodontocercus angustipennis Chopard 1954. Mem. Inst. franc. Afr. Noire 40(2): 84;
type locality: Mt. Nimba, Guinea (MNHN).
Material examined. Guinea, Mt. Nimba (♂ holotypus) (MNHN)
Distribution. After the description by Chopard (1954), Ragge (1962) recorded
another specimen from Sierra Leone. Massa (2013) recorded L. angustipennis also from

Bruno Massa / ZooKeys 951: 47–65 (2020)
50
the Central African Republic, but later Massa et al. (2020) stated that the specimens
were erroneously identied and actually they belong to L. condylus; in addition, they
wrote that other specimens belong to another two undescribed species, described below.
Leiodontocercus philipporum sp. nov.
http://zoobank.org/18E7A412-0C64-44B7-808C-C250EA4479BF
Figs 1, 7, 12, 19, 20
Material examined. Côte d’Ivoire, Lamto Nature Scientic Reserve, Bandama River,
4.IX.1982 (♂ holotypus) (BMPC); Côte d’Ivoire, Taï National Park, Research Station,
22.III–4.IV.2017, P. Moretto & P. Annoyer (3♀) (BMPC).
Description. Male. General habitus and colour. Predominantly green-brown,
two lateral black spots on fore margin of pronotum and corresponding hind margin
of head, black stripe interrupted on the hind margin of pronotum, abdomen yellow,
last abdominal tergite orange, antennal segments reddish, legs yellowish, hind tibiae
yellowish with black rings. Head and antennae. Eyes oval-roundish, prominent, an-
tennae long and thin. orax. Anterior margin of pronotum slightly concave, poste-
rior margin straight. Lower margin of pronotal lobes rounded. Tegmina very narrow.
Central part of the stridulatory le consists of ca 60 teeth (Fig. 7). e stridulatory
area of the left tegmen wider than the rest of tegmen (Fig. 12). Right tegmen without
mirror. Legs. Fore coxae armed. Tympana on fore tibiae open on outer, closed on in-
ner side. Fore femora with 8 inner ventral spines, fore tibiae with 4 inner and outer
ventral spines. Mid femora armed with 7 outer ventral spines, mid tibiae dorsally
with 2 inner spines, 7 spines on outer and inner ventral margins. Hind femora with
8–9 outer and inner ventral spines, hind tibiae straight with many ventral spines. Two
pairs of small spines on the outer and inner knees of hind femora. Abdomen. Cerci
stout and hairy, in frontal view apically triangular with serrated margins; ventrally
they have a long-tipped appendage (Figs 19, 20). Hind margin of the subgenital plate
nearly straight, styli absent.
Measurements (mm). Body length: 19.4; length of pronotum: 3.0; depth of prono-
tum: 3.2; length of hind femora: 20.0; length of tegmina: 24.4; width of tegmina: 3.3.
Etymology. Leiodontocercus philipporum sp. nov. is named after Philippe Annoyer
and Philippe Moretto, who organized a one-month entomological mission to Taï Na-
tional Park and Mt. Tonkoui of the Côte d’Ivoire, helping me in the night trapping
and generously providing all Orthoptera collected there.
Leiodontocercus spinicercatus sp. nov.
http://zoobank.org/F34AB84D-BFF9-4505-8CCE-C35AAB07FCCE
Figs 2, 3, 5, 10, 23, 24
Material examined. Central African Republic, Dzanga-Sangha Special Reserve, Camp
5, 15–16.II.2005, P. Annoyer (♂ holotypus); Dzanga-Sangha Special Reserve, Camp 5,

African Leiodontocercus and its species 51
Figures 1–3. Female ovipositor of Leiodontocercus: 1 10th abdominal tergite concealing the supra-anal
plate in the female of L. muticus sp. nov. from Gabon 2 ventral view of the ovipositor of L. spinicercatus
sp. nov. from Central African Republic 3 lateral view of the ovipositor of L. spinicercatus sp. nov. from
Central African Republic.

Bruno Massa / ZooKeys 951: 47–65 (2020)
52
7–8.II.2005 (light), P. Annoyer (1♀); Dzanga-Sangha Special Reserve, 15–16.X.2008
(light), P. Annoyer (1♀) (BMPC).
Description. Male. General habitus and colour. Predominantly green-brown,
two lateral black spots on fore margin of pronotum and corresponding hind margin
of head, black stripe interrupted on the hind margin of pronotum, abdomen yellow,
last abdominal tergite orange, antennal segments reddish, legs yellowish, hind tibiae
yellowish with black rings. Head and antennae. Eyes oval-roundish, prominent, an-
tennae long and thin. orax. Anterior margin of pronotum slightly concave, poste-
rior margin straight. Lower margin of pronotal lobes rounded. Tegmina very narrow.
Central part of the stridulatory le consists of ca 55 teeth (Fig. 5). e stridulatory
area of the left tegmen wider than the rest of tegmen (Fig. 10). Right tegmen without
mirror. Legs. Fore coxae armed. Tympana on fore tibiae open on outer, closed on in-
ner side. Fore femora with 7 inner ventral spines, fore tibiae with 4 inner and outer
ventral spines. Mid femora armed with 9 outer ventral spines, mid tibiae dorsally with
2 inner spines, 7 spines on outer and inner ventral margins. Hind femora with 8–9
outer and inner ventral spines, hind tibiae straight with many ventral spines. 2 pairs of
small spines on the outer and inner knees of hind femora. Abdomen. Cerci stout and
apically incurved, with an apical ventral pointed tip (Figs 23, 24). Hind margin of the
subgenital plate nearly straight, styli absent.
Measurements (mm). Body length: 14.2; length of pronotum: 2.9; depth of prono-
tum: 2.5; length of hind femora: 19.7; length of tegmina: 23.4; width of tegmina: 3.2.
Etymology. Leiodontocercus spinicercatus sp. nov. is named after the ventral spine
on the male cerci.
Distribution. It is known from the Dzanga-Sangha Special Reserve (Central Af-
rican Republic).
Leiodontocercus vicii sp. nov.
http://zoobank.org/6F371136-432D-4F01-B6AD-4FDDC631CB2C
Figs 4, 9, 21, 22
Material examined. Central African Republic, Dzanga-Ndoki NP, Lake 1, 8–10.
II.2012, SANGHA2012 Team (♂ holotypus) (BMPC); Dzanga-Ndoki NP, Lake 1, 20–
23.II.2012 (hand catching and light), SANGHA2012 Team (1♂ paratypus) (BMPC).
Description. Male. General habitus and colour. Predominantly green-brown,
two lateral black spots on anterior margin of pronotum and corresponding hind mar-
gin of head, black stripe interrupted on the posterior margin of pronotum, abdomen
yellow, last abdominal tergite orange, antennal segments reddish, legs yellowish, hind
tibiae yellowish with black rings. Head and antennae. Eyes oval-roundish, prominent,
antennae long and thin. orax. Anterior margin of pronotum slightly concave, poste-
rior margin straight. Lower margin of pronotal lobes rounded. Tegmina very narrow.
Central part of the stridulatory le consists of ca 50 teeth (Fig. 4). e stridulatory
area of the left tegmen less protruding backwards than in the other species (Fig. 9).

African Leiodontocercus and its species 53
Figures 4–8. Stridulatory le and detail of teeth in the following species of Leiodontocercus: 4L.vicii
sp.nov. 5 L. spinicercatus sp. nov. 6 L. condylus 7 L. philipporum sp. nov. 8 L. muticus sp. nov.
Right tegmen without mirror. Legs. Fore coxae armed. Tympana on fore tibiae open
on outer, closed on inner side. Fore femora with 8 inner ventral spines, fore tibiae with
4 inner and outer ventral spines. Mid femora armed with 7 outer ventral spines, mid
tibiae dorsally with 2 inner spines, 7 spines on outer and inner ventral margins. Hind
femora with 7–8 outer and inner ventral spines, hind tibiae straight with many ventral
spines. 2 pairs of small spines on the outer and inner knees of hind femora. Abdomen.
Cerci stout and apically swollen, with the apex down curved and its margins serrated
(Figs 21, 22). Posterior margin of the subgenital plate nearly straight, styli absent.
Female. Unknown.
Measurements (mm). Body length: 13.5–15.5; length of pronotum: 3.1–3.2;
depth of pronotum: 2.8–2.9; length of hind femora: 20.0–20.1; length of tegmina:
24.7–24.8; width of tegmina: 2.3–2.4.
Etymology. Leiodontocercus vicii sp. nov. is named after the nickname of my son-
in-law Vincenzo Cigna, as sign of his esteem and sincere friendship.

Bruno Massa / ZooKeys 951: 47–65 (2020)
54
Distribution. Presently it is only known from the Dzanga-Ndoki National Park
(Central African Republic).
Leiodontocercus condylus Ragge, 1962
Figs 6, 13, 15, 15a, 16, 27
Leiodontocercus condylus Ragge. 1962. Bull. Br. Mus. (Nat. Hist.) Ent. 13: 15; type
locality: Kibali-Ituri, Yindi (Democratic Republic of Congo) (NHM).
Material examined. Central African Republic, Dzanga-Ndoki National Park,
Dieké 25.XI.2010, P. Annoyer (1♂, 1♀); Dzanga-Ndoki National Park, Lake 1,
31.I–2.II.2012 (1♀), 12–13.II.2012 (1♂), 13–14.II.2012 (3♂), 17.II.2012 (1♀);
20–23.II.2012 (1♀), 22–23.II.2012 (1♀); 28–29.II.2012 (1♂) (hand catching
and light), SANGHA2012 Team; Lake 3, 25–26.II.2012 (light), P. Annoyer (1♀)
(BMPC & PAPC); Central African Republic, La Maboké, M’Baiki II.1964, M.
Pavan (1♂) (MSNP).
Remarks. Leiodontocercus condylus has the central part of the stridulatory le with
ca 50 thick teeth, that appear just deeper than in the other species (Fig. 6). e stridu-
latory area of the left tegmen is a little backwards protruding, more than in the other
species (Fig. 13). is species is characterized by cerci stout with an apical swelling
with the outer margin serrated and the inner part with two pointed black tipped teeth
(Figs 15, 16).
Distribution. Leiodontocercus condylus has been described from Zaire (= Dem-
ocratic Republic of Congo) and has been reported from Central African Republic
(Dzanga-Ndoki National Park) by Massa et al. (2020); it is here recorded also from
the M’Baiki forest in Central African Republic. Presently females are not recognized
at species level and were identied as L. condylus because they were collected together
with the males of this species.
Leiodontocercus muticus sp. nov.
http://zoobank.org/10E50D8E-F830-4D8D-B231-A74919255CB5
Figs 8, 11, 25, 26
Material examined. Gabon, Mikongo (Rougier), Mts de Cristal (secondary forest)
(430 m) 0°29'47"N, 11°10'42"E, 28.VII–12.VIII.2019 (MV Light Trap), Albert,
Aristophanous, Bie Mba, Dérozier, Moretto (♂ holotypus, 1♂ paratypus) (ANHRT);
Gabon, Mikongo (Rougier), Mts de Cristal (secondary forest) (430 m) 0°29'47"N,
11°10'42"E, 28.VII–12.VIII.2019 (Actinic Light Trap), Albert, Aristophanous, Bie
Mba, Dérozier, Moretto (1♀) (ANHRT); Gabon, Nyonié (lowland forest) 0°2'22"S,
9°20'25"E (10 m) 23–28.VIII.2019 (LepiLED Light Trap), Albert, Aristophanous,
Bie Mba, Dérozier, Moretto (1♂ paratypus) (BMPC); Gabon, Lope National Park

African Leiodontocercus and its species 55
Figures 9–14. Dorsal view of the head, pronotum and the stridulatory area of the following species of Lei-
odontocercus: 9 L. vicii sp. nov. 10 L. spinicercatus sp. nov. 11 L. muticus sp. nov. 12 L. philipporum sp.nov.
13 L. condylus 14 L. angustipennis (holotypus).

Bruno Massa / ZooKeys 951: 47–65 (2020)
56
Figures 15–20. Frontal and lateral view of cerci of the following species of Leiodontocercus: 15, 16 L. condylus
(inset 15a: cercus after Ragge 1962), 17 L. angustipennis (holotypus; inset 17a cercus after Ragge 1962)
18L. malleus (holotypus; inset 18a cercus after Ragge 1962) 19, 20 L. philipporum sp. nov. 17 and 18after
OSFonline (http://orthoptera.speciesle.org/Common/basic/Taxa.aspx?TaxonNameID=1136208).

African Leiodontocercus and its species 57
Figures 21–26. Frontal and lateral view of cerci of the following species of Leiodontocercus: 21, 22L.vicii
sp. nov. 23, 24 L. spinicercatus sp. nov. 25, 26 L. muticus sp. nov.

Bruno Massa / ZooKeys 951: 47–65 (2020)
58
Figure 27. Multi-stratied can opy of the forest of the Dzanga-Ndoki National Park (Central African Re-
public), where Leiodontocercus species may occur exploiting dierent ecological niches (Photo by P. Annoyer).
4.IV.2014 (light), N. Moulin (1♀) (BMPC); Cameroon, Campo Ma’an National
Park (lowland rainforest) (950 m) 10–22.III.2018 (MV Light Trap), Fotsing, Ishmael,
Miles, Saan (1♂ paratypus, 1♀) (ANHRT); Cameroon, Mundame (1♀) (NHW).
Description. Male. General habitus and colour. Green-brown, tegmina brown-
ish, abdomen yellow, last abdominal tergite brown, cerci brown, antennal segments
reddish, legs yellowish. Head and antennae. Eyes oval-roundish, prominent, antennae
long and thin. orax. Anterior margin of pronotum slightly concave, posterior mar-
gin rounded. Lower margin of pronotal lobes rounded. Tegmina very narrow. Central
part of the stridulatory le consists of ca 100 teeth (Fig. 8). e stridulatory area of
the left tegmen wider than the rest of tegmen (Fig. 11). Mirror absent on the right
tegmen. Legs. Fore coxae armed. Tympana on fore tibiae open on outer, closed on
inner side. Fore femora with 9 inner ventral spines, fore tibiae with 6 inner and outer
ventral spines. Mid femora armed with 8 outer ventral spines, mid tibiae dorsally with
2 inner spines, 6 spines on outer and inner ventral margins. Hind femora with 9–10
outer and inner ventral spines, hind tibiae straight with many ventral spines. 2 pairs of
small spines on the outer and inner knees of hind femora. Abdomen. Cerci stout and
hairy, in frontal view slightly incurved with an apical bulge just serrated on inner mar-
gin (Figs 25, 26). Posterior margin of the subgenital plate nearly straight, styli absent.

African Leiodontocercus and its species 59
Female. Interestingly, the females collected with males of L. muticus sp. nov. have
black spots on the pronotum and black rings on the hind legs, like the other species of
the genus. In addition, an alive female specimen photographed by P. Moretto (Fig. 29)
shows alternate black and white abdominal sternites. In the males of L. muticus sp. nov.
these black markings are absent. e female from Mundame (Cameroon) at NHW is
tentatively identied, in absence of males.
Measurements (mm). Body length: 12.9–14.9; length of pronotum: 2.9–3.2;
depth of pronotum: 3.0–3.2; length of hind femora: 19.6–19.7; length of tegmina:
24.4–24.6; width of tegmina: 3.4–3.5.
Etymology. Leiodontocercus muticus sp. nov. is named after the complete absence
of any spine or appendage on the male cerci.
Distribution. is species is known from some forested areas in Gabon and in
Cameroon, situated about 300 km apart.
Leiodontocercus malleus Ragge, 1962
Fig. 18, 18a
Leiodontocercus malleus Ragge. 1962. Bull. Br. Mus. (Nat. Hist.) Ent. 13: 14; type lo-
cality: Western Region, near Wiawso (Ghana) (NHM).
Notes. is species is presently known only from the male holotype, another male
paratype from Tafo (Ghana) and one female paratype from Ashanti (Ghana), localities
not far to the north-east of Wiawso. Cerci are shown in Fig. 18 and 18a.
Discussion
The structure of the stridulatory file
e song produced by species of this genus is, to date, still unknown. Nonetheless,
the stridulatory le (the structure that allows most Orthoptera to produce a song) was
examined in detail for any discernable morphological dierences. All the species of Lei-
odontocercus have a very short stridulatory le under the male’s left forewing, no longer
than 0.5 mm (Figs 4–8). At rst glance, even at very high magnication, it appears
identical in all the males. However, a closer and more detailed examination revealed
dierences in the number of teeth, but not in their arrangement. e stridulatory le
consists of very thick central teeth, that vary in number in the dierent species; in ad-
dition, the distal and the proximal parts of the stridulatory le have a small number
of evenly-spaced small teeth. Evidently, the dierence in the number of teeth (even
though their structural arrangement is similar) and their dierent depth will produce a
dierent song, which permits the male to attract a female of the same species. Among
the examined species, the highest number of teeth in the central part of the stridula-

Bruno Massa / ZooKeys 951: 47–65 (2020)
60
tory le (ca 100) has been found in L. muticus sp. nov., while a lowest number (ca 50)
has been found in L. condylus, L. spinicercatus sp. nov. and L. vicii sp. nov., and an
intermediate number (ca 60) was noted in L. philipporum sp. nov. Very likely, the song
is produced using both central, distal and proximal teeth. It is remarkable to note that
the three species with similar stridulatory les co-occur in the same areas of Central
African Republic.
The stridulatory area
e left and right tegmina of males bear the stridulatory area; this body portion is
generally well characterized for each species. However, species of Leiodontocercus do
not show great dierences: the right forewing lacks the characteristic mirror, while the
left forewing has an evident arched bulge that corresponds to the stridulatory le un-
der the wing (Figs 9–14). Small diagnostic characters are recognizable in the dierent
taxa: L. vicii sp. nov. has the left tegmen particularly narrow also in the stridulatory
area, while the other species described in the present work have a deeper stridulatory
area compared with the rest of the wing. In addition, L. muticus sp. nov., the species
with the highest number of teeth in the stridulatory le, has a matching area on the
dorsal left tegmen that is longer compared to other species. Furthermore, L. condylus
has a stridulatory area that protrudes further backwards than that of the other species,
while L. malleus has a brownish stridulatory area, sharply contrasting with the rest of
the green-coloured tegmina (Ragge 1962); this brownish stridulatory area may also be
observed in L. condylus.
The shape of male cerci
e shape of the male cerci is the best diagnostic character of this genus; currently
three dierent species have been described on the basis of the dierent cerci, and fur-
ther, four new species are here described, mainly based on the shape of the cerci. e
best way to observe cerci is through frontal and lateral views (Figs 15–26); this allows
visibility of a possible ventral appendage, not otherwise visible through a dorsal view.
Cerci are used by males during mating; many species of Tettigoniidae have been ob-
served to use their cerci as a pincer that immobilizes the female’s ovipositor or abdo-
men (e.g., Vahed et al. 2014). It is highly likely that the shape of the male cerci and
mating modality are congruent and that a female would recognize the male of the
same species by the song it emits. us, we may presume that the female reacts to the
stimulus originating from the song of a male of the same species and, subsequently, the
male cerci could act as a second stimulus during mating.
Habitat and habits of Leiodontocercus species
e Guineo-Congolian region, the tropical forest region of Central and West Africa,
covers about 90% of the total forest surface in central Africa, but merely 6% in West

African Leiodontocercus and its species 61
Africa (Malhi et al. 2013). Most species of tropical African Tettigoniidae live in the
multi-stratied canopy, and are nocturnal. All the species of Leiodontocercus have been
found (generally single individuals) in multi-stratied and well-preserved primary for-
ests (Fig. 27), and, in some cases, in secondary forests.
One live male specimen of L. condylus was photographed by Samuel Danous in
the Central African Republic (Dzanga-Ndoki National Park) in 2010 and one female
of L. muticus sp. nov. was photographed by Philippe Moretto in Gabon (Figs 28, 29).
ey show a peculiar leg posture, with the femora more or less vertically positioned
in respect to the body, similar to the posture of a spider or some grasshoppers of the
Eumastacidae (C. Hemp, pers. comm.). e dark rings on hind tibiae, when exposed
(as in these cases), and dark spots and markings on the body (including the abdomen
of the female), may function in disruptive mimicry. Dark markings on the wings or on
the legs are common within those species occurring inside the canopy (e.g., Enochletica
ostentatrix Karsch, 1896, Myllocentrum species, some Arantia and Eurycorypha species,
among others); it is very likely an adaptation to minimise predation by birds or other
forest vertebrates, as well as invertebrates through mimicry.
Speciation in Leiodontocercus
Leiodontocercus specimens are scarce in museums and collections, and this is probably
the reason why their diversity has not been appreciated earlier. In addition, the species
belonging to this genus are very small and delicate, with a body length that does not
exceed 20 mm (15 mm on average) and a stridulatory le of no more than 0.5 mm;
this makes it all the more dicult to study the very few existing, previously mounted
specimens, accurately. Figure 30 shows the distribution of the currently known seven
species of Leiodontocercus; interestingly, only the Central African Republic (protected
areas Dzanga-Ndoki and Dzanga-Sangha) holds three species, which very likely occur
syntopically. is nding probably results from more intensive research carried out in
those areas, mainly through the use of light traps (UV), both on the forest oor and
in the canopy (35 to 55 meters high) (cf. Massa 2013, Massa et al. 2020). e co-
occurrence of dierent species distinguished by their dierent songs, dierent court-
ship behaviour, and small morphological dierences including male cerci indicates the
existence of reproductive barriers between them.
e high local biodiversity in central-western tropical African forests is shown by
the high number of species of insects, Orthoptera being a case point. Generally, African
Phaneropterinae are considered a taxonomic group with a great propensity to speciate;
probably it is the forest ecosystem that facilitated speciation of most African Phan-
eropterinae. Leiodontocercus species, under a selective regime, may have acquired ad-
vantageous traits, that have increased local dierentiation rate (cf. Simões et al. 2016).
e case of speciation in Leiodontocercus is similar to that of Tetraconcha Karsch, 1890
(Phaneropterinae, Otiaphysini) (Massa 2017). Both genera show multiple speciation
within tropical forest ecosystems of central and western Africa. Concerning Leiodon-
tocercus, the small morphological disparity is very likely the eect of an evolutionary

Bruno Massa / ZooKeys 951: 47–65 (2020)
62
Figures 28, 29. Mimicry of Leiodontocercus condylus Ragge, 1962, Central African Republic, Dzanga-
Ndoki National Park, 25th November 2010 (Photo by S. Danous) (above) and of L. muticus sp. nov.,
Gabon, Mikongo, 12th August 2019 (Photo by P. Moretto) (below).
radiation, which may depend on local isolation. In the case of Tetraconcha, the mor-
phological character observed to distinguish species is the stridulatory system, and in
the case of Leiodontocercus, the main dierences lie in the shape of the male cerci. Both
the stridulatory system and cerci shape are linked to courtship and mating.

African Leiodontocercus and its species 63
Figure 30. Updated distribution of the seven currently known species of the genus Leiodontocercus.
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). In accordance with
Maley (1996), African rainforests retreated during dry periods after the Ice Age, and
climate uctuations would have favored the dispersion of species. e climate of tropi-
cal Africa following the Ice Age was warmer and wetter than present (African humid
period; Willis et al. 2013); in most Central African areas it shifted to a drier regime
between 4000 and 2000 years BP, when the forest cover retreated (Willis et al. 2013).
is may have allowed local isolation of populations that evolved in the absence of gene
ow. Speciation events are often correlated with humid and dry periods; forest expan-
sion during humid periods and retraction during dry periods are considered the best
explanation for the patterns of geographical species distribution found on East African
mountains (Schultz et al. 2007, Hemp et al. 2015); this climatic episode has also been
proposed for Tetraconcha by Massa (2017) and is here proposed also for Leiodontocercus.
Acknowledgements
I wish to thank Philippe Moretto and Philippe Annoyer, Organizer of the expedition
Sangha 2012 and President of the Association Insectes du Monde (www.insectesdu-
monde.org), respectively, who kindly let me study the material collected during the
2005–2012 Sangha entomological missions (Central African Republic), as well as to
Samuel Danous and Matias Loubes for their collaboration and help during the col-
lecting nights at light in the Taï National Park (Côte d’Ivoire) in March 2017, both
at ground level and in the canopy. I am grateful to Samuel Danous for providing an
interesting photograph of a species of Leiodontocercus taken in Central African Repub-
lic, to Philippe Moretto for a photograph of a female of Leiodontocercus from Gabon
and to Philippe Annoyer for a photograph of the forest habitat of the Dzanga-Ndoki
National Park (Central African Republic). I am indebted to Richard Smith, Chairman

Bruno Massa / ZooKeys 951: 47–65 (2020)
64
of the African Natural History Research Trust (ANHRT) (Hereford, UK), who loaned
specimens collected in Gabon and Cameroon, to Hitoshi Takano, researcher and cura-
tor of ANHRT and to the collectors and collaborators of the Cameroon and Gabon
entomological expeditions, which were carried out by ANHRT and the Association
Catharsius (in Gabon: Philippe Moretto, Marios Aristophanous, Violette Dérozier
and Jean-Louis Albert; in Cameroon: Ernest Fotsing, Kobe Ishmael, William Miles,
Szabolcs Saan and Gábor Simonics). ANHRT and I would very much like to extend
our thanks to the following: Ministre des Eaux et Forêts of Gabon, Prof. Lee White;
Monsieur l’Administrateur Général of Centre National de la Recherche Scientique
for the research authorizations; the Rector of the Université des Sciences et Techniques
of Masuku, Prof. Ella Missang Crépin; the director of the Département de Biologie,
Prof. Nicaise Lepengue and Dr Stefan Ntie. Finally, I thank Nicolas Moulin for provid-
ing one female specimen from Lope National Park, in Gabon.
I am indebted with Claudia Hemp, who revised the rst manuscript, and to Louis
Cassar for the English revision. is research received support from the Synthesys Project,
which was nanced by European Community Research Infrastructure Action under the
FP7 “Capacities” Programme at the Museo Nacional de Ciencias Naturales, Madrid (CSIC)
(2013: ES-TAF-2438), the Museum für Naturkunde, Berlin (2014: DE-TAF-4109),
the Naturhistorisches Museum, Vienna (2016: AT-TAF-5324), the National Museum,
Prague (2016: CZ-TAF-5559) and the Royal Belgian Institute of Natural Sciences, Brux-
elles (2017: BE-TAF-6319). I am especially indebted to Mercedes Paris (Museo Nacional
de Ciencias Naturales of Madrid), Michael Ohl (Museum für Naturkunde of Berlin),
Suzanne Randolf and Harald Bruckner (Naturhistorisches Museum, Vienna), Jérôme
Constant (Royal Belgian Institute of Natural Sciences, Bruxelles), Martin Fikáček (Na-
tional Museum Natural History, Prague), Laure Desutter (Muséum National d’Histoire
Naturelle, Paris), Stefano Maretti and Jessica Maei (Museo Storia Naturale University of
Pavia), who facilitated the examination of specimens preserved in their museums.
Collecting authorizations and research permits were obtained as follows: 019/
UB/DSV2012 of 16.I.2012 from Bangui University, Central African Republic; 021/
MESRS/DGRI of 15.II.2017 from the Ministère de l’Einsegnement Supérieur e de la
Recherche Scientique of Côte d’Ivoire; AR0029/19/MESRSTT/CENAREST/CG/
CST/CSAR of 11.VII.2019, issued by the Commission Scientique d’Examen des
Demandes d’Autorisations de Recherche of the Ministère de l’Enseignement Supé-
rieur, de la Recherche Scientique et du Transfert des technologies du Gabon.
References
Chopard L (1954) La réserve naturelle intégrale du Mont Nimba. II. Orthoptères Ensifères. Mé-
moires Institut français Afrique noire 40: 25–97. https://doi.org/10.1111/j.1365-2311.1954.
tb00767.x
Hadley A (2008) Combine Z. www.hadleyweb.pwp.blueyonder.co.uk [downloaded on Febru-
ary 2009]

African Leiodontocercus and its species 65
Heller K-G (2006) Song Evolution and Speciation in Bushcrickets. In: Drosopoulos S, Clar-
idge MF (Eds) Insect Sounds and Communication. Taylor & Francis, Boca Raton, Lon-
don, New York, 137–151. https://doi.org/10.1201/9781420039337.ch9
Hemp C, Kehl S, Schultz O, Wägele JW, Hemp A (2015) Climatic uctuations and orogenesis
as motors for speciation in East Africa: case study on Parepistaurus Karsch, 1896 (Orthop-
tera). Systematic Entomology 40: 17–34. https://doi.org/10.1111/syen.12092
Maley J (1996) e African rain forest – main characteristics of changes in vegetation and
climate from Upper Cretaceous to the Quaternary. Proceedings of the Royal Society of
Edinburgh 104: 31–73. https://doi.org/10.1017/S0269727000006114
Malhi Y, Adu-Bredu S, Asare RA, Lewis SL, Mayaux P (2013) African rainforests: past, present
and future. Philosophical Transactions of the Royal Society B 368 (1625). https://doi.
org/10.1098/rstb.2012.0312
Massa B (2013) Diversity of leaf katydids (Orthoptera: Tettigoniidae: Phaneropterinae)
of Dzanga-Ndoki National Park, Central African Republic, with selected records from
other African countries. Journal of Orthoptera Research 22(2): 125–152. https://doi.
org/10.1665/034.022.0201
Massa B (2017) Revision of the tropical African genus Tetraconcha (Orthoptera: Tettigoniidae:
Phaneropterinae) with the description of ten new species. Journal of Orthoptera Research
26: 211–232. https://doi.org/10.3897/jor.26.21469
Massa B, Annoyer P, Perez C, Danous S, Duvot G (2020) Orthoptera Tettigoniidae (Cono-
cephalinae, Hexacentrinae, Phaneropterinae, Mecopodinae, Hetrodinae) from some
protected areas of Central African Republic. Zootaxa 4780(3): 401–447. https://doi.
org/10.11646/zootaxa.4780.3.1
Ragge DR (1962) A revision of the genera Phlaurocentrum Karsch, Buettneria Karsch and
Leiodontocercus Chopard (Orthoptera: Tettigoniidae). Bulletin British Museum (Natural
History) Entomology 13: 1–17. http://www.biodiversitylibrary.org/item/102952#page/8/
mode/1up
Ragge DR (1980) A review of the African Phaneropterinae with open tympana (Orthoptera:
Tettigoniidae). Bulletin British Museum (Natural History) Entomology 40: 1–192. http://
www.archive.org/details/bulletinofbritis40entolond
Schultz O, Hemp C, Hemp A, Wägele JW (2007) Molecular phylogeny of the endemic East
African ightless grasshoppers Altiusambilla Jago, Usambilla (Sjöstedt) and Rhainopomma
Jago (Orthoptera: Acridoidea: Lentulidae). Systematic Entomology 32: 1–8. https://doi.
org/10.1111/j.1365-3113.2007.00395.x
Simões M, Breikreuz L, Alvarado M, Baca S, Cooper JC, Heins L, Herzog K, Lieberman BS
(2016) e evolving theory of Evolutionary Radiations. Trends in Ecology and Evolution
31: 27–34. https://doi.org/10.1016/j.tree.2015.10.007
Vahed K, Gilbert JDJ, Weissman DB, Barrientos-Lozano L (2014) Functional equivalence of
grasping cerci and nuptial food gifts in promoting ejaculate transfer in katydids. Evolution
68(7): 2052–2065. https://doi.org/10.1111/evo.12421
Willis KJ, Bennett KD, Burrough SL, Macias-Fauria M, Tovar C (2013) Determining the re-
sponse of African biota to climate change: using the past to model the future. Philosophical
Transactions of the Royal Society B 368(1625). https://doi.org/10.1098/rstb.2012.0491