Research Article |
Corresponding author: Charly Oumarou Ngoute ( coumaroungoute@yahoo.fr ) Academic editor: Corinna S. Bazelet
© 2017 Charly Oumarou Ngoute, Sévilor Kekeunou.
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.
Citation:
Ngoute C, Kekeunou S (2017) Redescription and diagnosis of the African genus Gemeneta Karsch, 1892 (Orthoptera: Acrididae: Catantopinae). Journal of Orthoptera Research 27(2): 161-170. https://doi.org/10.3897/jor.26.19995
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The subfamily Catantopinae is a poorly defined subfamily of the Acrididae, having many genera that require taxonomic clarification. The genus Gemeneta from this subfamily is found in African forests and has only two described species, Gemeneta terrea and Gemeneta opilionoides. However, the original descriptions of the genus relied heavily on external female morphology, and a description of male G. opilionoides was completely lacking. The present work provides the first description of the male of G. opilionoides, a morphological description of both species, including internal genitalia, and clarifies the generic diagnosis. This study is a contribution to a better understanding of the taxonomy of Catantopinae in the tropical forests of Africa.
Caelifera , Cameroon, forest, genitalia, male description, taxonomy, Uganda
The grasshopper subfamily Catantopinae is a rather large taxon with many genera and a great variety of forms, including around 16 tribes, about 382 genera and 52 species distributed over the Old World (
The distributions of the two species overlap in the Congo Basin forests (Fig. 1), but G. opilionoides is very rare and difficult to find there, suggesting that it has a specialized ecological niche in the forests. Deforestation poses a high risk of extinction for this already scarce species, especially in Cameroon where almost all forests are being rapidly destroyed through human activities. Hence, there is an urgent need to ascertain the taxonomy, biology and ecology of this species. The original descriptions of the genus Gemeneta relied heavily on external female morphology, and a description of male of G. opilionoides is lacking. Although
The specimens used in this study were collected in the forest margin benchmark area of the Southern Cameroon plateau and in the Mpanga forest in the south of Uganda. The Southern Cameroonian plateau (between 3°27'N, 11°32'E and 4°10'N, 11°49'E), with an average altitude of 650–700 m, is a part of the plateau which forms the northern and western edge of the Congo basin (
The morphology of all the specimens was described and measured using a Wild microscope under 25-50× magnification with a digital stage and a graticule eyepiece. Drawings were made using the same microscope with drawing tube attachment and edited in Photoshop CS6 (Adobe Systems Inc., San José, California, USA).
The following measurements were made (Table
The mean and standard error of each measurement was calculated by the software PAST version 3.12.
Standard methods for the extraction and preparation of the internal genitalia were used to extract the male and female genitalia studied. The internal genitalia were extracted, macerated in 8% KOH solution, neutralized in 5% dilute acetic acid, then stained in acid fuchsin and stored in glycerine before examination and drawing. The terminology of phallic complex used is derived from
General terms: Ectophallus: external part of the phallus organ consisting mainly of the ectophallic membrane plus the cingulum and its rami; Endophallus: internal part of the phallic organ, consisting of the aedeagus and its appendices, ejaculatory and spermatophore sac, and the ventral valves of the aedeagus; Epiphallus: strongly sclerotinized sclerite located on the dorsal part of the phallic organ; Spermatheca (S): a vesicle or a blind-ending duct, the part of the female genitalia that receives and stores the ejaculatory product from the male.
Specific terms: Ancorae (A), Ventral aedeagal valves (Vv), Apodemes of cingulum (Apd), Bridge (B), Columella (C), Valves of cingulum (Cv), Ectophallic sheath (Es), Egg-guide (Eg), Floor pouches (Fp), Gonopore processes (Gpr), Lophi (L), Preapical appendix (Pa), Posterior edge (Pe), Zygoma (Zyg) (see Figs 7–8).
Escalera
= Bolívar, 1905 (syn.
G. terrea
The generic description presented in this work differs somewhat from the description of
Body with integument slightly or strongly tuberculate and granulated; antenna longer than head and pronotum together; head conical, frons incurved; fastigium of vertex elongate-angular and sloping forwards; frontal ridge weak, strongly constricted below lateral ocelli; eyes convex; ocelli small. Pronotum cylindrical, with median and lateral carinae substituted by granulae; dorsum crossed by three sulci; prosternal process conical; external apical spine of the hind tibia absent; elytra and wings absent; the third segment of foot longer than the first, and the first longer than the second. Male supra-anal plate elongated, angular, with deep transverse furrow. Subgenital plate conical, with acute apex. Valves of ovipositor long, straight, with slightly curved apices; cercus conical. Epiphallus with wide bridge, small ancorae and incurved lobiform lophi; ventral aedeagal valves and valves of cingulum elongated, enclosed in a wide ectophallic sheath; anterior apodemes of aedeagus divergent with rounded apices; gonopore process pointed; zygoma wide, apodemes of cingulum parallel with acute apices.
Africa, West-Central Tropical Africa Cameroon: Buea; 2 ♂♂, 1 ♀; MfN.
Buea, Cameroon (4°15'27"N, 9°24'1"E) by
Uganda, Mpanga forests, 4 ♂♂, 3 ♀♀, in the collection of Dr. Rowell, Switzerland; Cameroon, Zamakoe forests, 1 ♂, 1 ♀; Ongot forests, 1 ♀, in the Laboratory of Zoology, University of Yaoundé 1, Cameroon.
Body slightly elongated, 5 to 6 times the length of the pronotum; integument rugose. Head conical, the maximum width of head across the eyes almost as long as the pronotum in the males, slightly shorter in females; fastigium of vertex clearly projecting forward with a deep furrow which merges with frontal ridge sulcus, apex of fastigium rounded, fastigium 1/4 the length of pronotum and about 1/2 the length of the fastigium of G. opilionoides (Table
Body generally brownish. Antenna brown; eyes black with a characteristic brown band in the upper half; prothoracic and mesothoracic legs brown mottled with light green in life; internal face of hind femur blackish, external upper area brown, median external area green drying black, lower inner area of hind femur and tibia slightly greenish to blueish in life.
Measurements (mm) of G. terrea and G. opilionoides. The values in the table represent: mean ± standard error (min–max). All measurements for G. terrea repeated for five specimens, except tarsal measurements which were repeated for four specimens. Only one male and one female of G. opilionoides were available for study so no range of values could be provided for this species.
Species | G. terrea | G. opilionoides | ||
---|---|---|---|---|
Sex | Male | Female | Male | Female |
L | 20.02±0.36 (18.87–20.97) |
29.89±0.93 (27.52–32.02) |
21.94 | 29.43 |
FL | 0.99±0.04 (0.86–1.13) |
1.26±0.03 (1.15–1.33) |
1.52 | 2.15 |
CV | 4.51±0.09 (4.16–4.7) |
5.97±0.25 (5.54–6.7) |
4.8 | 5.81 |
P | 3.37±0.06 (3.24–3.58) |
4.97±0.14 (4.49–5.35) |
3.83 | 4.73 |
F | 12.31±0.15 (12.06–12.92) |
16.48±0.18 (15.99–17.07) |
14.66 | 19.33 |
FD | 2.67±0.03 (2.61–2.79) |
3.44±0.11 (3.07–3.67) |
2.56 | 3.48 |
Ta1 | 1.34±0.09 (1.11–1.54) |
1.65±0.05 (1.53–1.79) |
1.67 | 1.86 |
Ta2 | 0.51±0.04 (0.44–0.62) |
0.58±0.04 (0.45–0.66) |
0.48 | 0.63 |
Ta3 | 1.60±0.07 (1.43–1.77) |
2.01±0.06 (1.83–2.13) |
2.08 | 2.50 |
Characters | G. terrea | G. opilionoides |
---|---|---|
Body coloration | Body generally entirely brownish; median inner area of hind femur blackish (Figs 2–3) | Body greenish mottled with brown dark; median inner area of hind femur greenish (Figs 4–5) |
Integument | Integument less granulated and less tuberculate in pronotum (Figs 2, 6C) | Integument granulated and strongly tuberculate in pronotum (Figs 4, 6D) |
Fastigium of vertex | Fastigium of vertex with a deep apical furrow (Fig. 6A) | Fastigium of vertex without apical furrow (Fig. 6B) |
Length of cercus | Cercus shorter than the paraproct in female (Fig. 6E) | Cercus almost as long as the paraproct in female (Fig. 6F) |
Apical valves of penis | Ventral aedeagal valves slender and strongly elongated (Figs 7E, G, I) | Ventral aedeagal valves dorsally flattened and curved outwards (Figs 7F, H, J) |
Lophi | Lophi lobiform and narrow (Figs 8C, G) | Lophi lobiform and wide (Figs 8D, H) |
Escalera
opilionoides
= Bolívar, 1905 (syn.
Gemeneta
rostrotuberculata
= Kevan, 1956 (syn.
E. opilionoides: Africa, West-Central Tropical Africa, Equatorial Guinea, Cabo San Juan, Biafra; 1 ♀; MNCN Madrid Mus.
Biafra, Equatorial Guinea (1°18'284"N, 9°36'336"E) By
Cameroon, Ngutadjap forests, 1 ♂, 1♀, in the Laboratory of Zoology, University of Yaoundé 1, Cameroon.
The species differs from G. terrea in having the integument strongly granulated and tuberculate, body greenish mottled with dark brown; median inner area of hind femur greenish, fastigium of vertex without apical furrow, cercus almost as long as the paraproct in female, ventral aedeagal valves dorsally flattened and curved outwards, lophi lobiform but wide.
Body slightly elongated, 5 to 6 times the length of the pronotum; integument granulated and strongly tuberculate in pronotum. Head strongly conical, the maximum width of head across the eyes almost as long as the pronotum; fastigium about 1/2 the length of the pronotum and nearly 2 times longer than the fastigium of G. terrea (Table
Body greenish with brown color in some parts; vertex, frons and genae green mottled brown; antennae brown basally, blackening distally. Pronotum greenish brown with discontinuous brown bands on the lateral lobes in life; knee light brown; median inner and external areas of femur light green, lower inner and external areas greenish; upper inner and external areas greenish but mottled brown; posterior tibia greenish; tarsus red-brown. Abdomen greenish with discontinuous brown bands in the lateral parts, most pronounced behind the hind femur; external genitalia green-yellowish.
Ectophallus and endophallus of Gemeneta spp. A, B. Entire phallic complex without epiphallus in lateral view; C, D. Entire phallic complex without epiphallus in dorsal view; E, F. Endophallus in ventral view; G, H. Endophallus in lateral view; I, J. Endophallus in dorsal view; A, C, E, G, I. G. terrea and B, D, F, H, J. G. opilionoides; Apodemes of cingulum (Apd): pair of ectophallic sclerotized structures situated dorsally to endophallus; Valves of cingulum (Cv): pair of valves projecting from the posterior end of the cingulum from the arch of cingulum; they form the upper valves of the aedeagus; Ectophallic sheath (Es): the membrane part of ectophallus covering the ventral aedeagal valves and valves of cingulum, often partially sclerotized; Gonopore processes (Gpr): pair of ventral processes from the aedeagal valves, functioning as a pinch valve between the ejaculatory and spermatophore sacs; Ventral aedeagal valves (Vv): endophallic valves, divided in two parts; Zygoma (Zyg): transverse dorsal part of cingulum, connecting the apodemes. Scale bars = 0.5 mm.
Ectophallus, epiphallus, spermatheca and subgenital plate of Gemeneta spp. A, B. Ectophallus in ventral view; C, D. Epiphallus in axial view; E, F: Epiphallus in lateral view; G, H. Epiphallus in dorsal view; I. Spermatheca in dorsal view; J. Subgenital plate in lateral view; K. Subgenital plate in dorsal view; A, C, E, G, I, J, K. G. terrea and B, D, F, H. G. opilionoides; Ancorae (A): a pair of processes or projections from the anterior margin or the dorsal surface of the epiphallus; Bridge (B): transverse part of epiphallus connecting the lateral parts; Lophi (L): lobiform processes near the posterior margin of the epiphallus; Columella (C): columnar structures on either side of the egg-guide in the subgenital plate; Egg-guide (Eg): median, dorsally produced part of the posterior edge in the subgenital plate; Floor pouches (Fp): pair of short anterior invaginations in the floor of the subgenital plate; Preapical appendix (Pa): preapical dilatation of the spermathecal duct; Posterior edge (Pe): pair of short posterior invaginations of the border that meets the floor in the subgenital plate. Scale bars = 0.5 mm.
The presence of a fastigial furrow in G. terrea is a strange character, because the fastigial furrow is not a common morphological structure in the Catantopinae but rather typical for the Pyrgomorphidae. As shown above, this is not in fact a generic character of Gemeneta, but only of the species G. terrea. Nevertheless, there is a strong resemblance between the different genital parts of G. terrea and G. opilionoides. Only minimal differences were observed in the width of the lophi as well as the form of the apical valves of the penis.
Based on these characters, the genus Gemeneta can be maintained in the Catantopinae. The structure of the spermatheca in G. terrea is typical for the Catantopinae, with a long tubular duct and vermiform preapical appendix, and lacking distinct terminal ampullae. Indeed, when
The distribution of G. terrea and G. opilionoides in Africa is poorly known and needs to be clarified. However, G. terrea is found in the Congo Basin forests, in West Africa (Nigeria, but not in Ghana (
We thank Miss F.C.A. Um Nyobe and Mr. A.R. Nzoko Fiemapong, two students of the University of Yaoundé 1, who helped in collecting specimens in the field. We thank Dr. M. Lecoq and Dr. D. Hunter for improving the manuscript. We also extend thanks to Prof. C.H.F. Rowell for his support, instruction and orientation during this work. This work was also made possible by funding from the Rufford Small Grant (Application ID: 19665-1) to the first author of this manuscript.
Data type: Microsoft Excel 97-2003 Worksheet (.xls)
Explanation note: Table