Limnogeton hedenborgi ( Stål, 1854 ), Stal, 1854

Ribeiro, José Ricardo I., Meyin-A-Ebong, Solange E., Le-Gall, Philippe & Guilbert, Eric, 2014, A taxonomic synopsis of Limnogeton Mayr, 1853 (Insecta: Hemiptera: Heteroptera: Belostomatidae), Zootaxa 3779 (5), pp. 573-584 : 578-581

Limnogeton hedenborgi ( Stål, 1854)

( Figs. 3–4 )

Borborotrephes hedenborgi Stål, 1854: 240 .

Limnogeton hedenborgi: Mayr (1863) : 360.

Limnogeton fieberi: Mayr (1871) : 431 (nec Mayr). Limnogeton hedenborgi: Montandon (1896) : 517. Limnogeton hedenborgi: Poisson (1949) : 7.

Limnogeton expansum: Poisson (1949) : 9 (in part) (nec Montandon). Limnogeton hedenborgi: Poisson (1954) : 12.

Limnogeton hedenborgi: Poisson (1967) : 1324.

Limnogeton fieberi: Poisson (1968a) : 26.

Limnogeton hedenborgi: Poisson (1969) : 16.

Limnogeton fieberi: Linnavuori (1971) : 355 (in part). Limnogeton expansum: Linnavuori (1971) : 356 (in part).

Types. Limnogeton hedenborgi was described based on a holotype which was labeled as being from Egypt (according to Stål 1854), deposited in NHRS. This specimen was not examined.

Material examined. [?]. “Place” Kusodaso, “Date” 23.III.1955, “Host ---”, “2582”, N. Nieser det. 1976 [as L. scutellatum ], J. R. I. Ribeiro det. 2013 [as L. hedenborgi ]: 1 f (NC). SENEGAL. Kolda, 05.II.1981, (B. Sigwalt “leg.”), J. R. I. Ribeiro det. 2011: 1 f ( MNHN). EGYPTE. 1880, (Letourneux), J. R. I. Ribeiro det. 2011, A. L. Montandon det. 1899: 2 f ( MNHN); identified as Borborotrephes hedenborgi by H. Lucas det.: 1 f ( MNHN); Suez, XI.1868: 1 f ( MNHN); (Letouneux 66-96): 1 f ( MNHN); (Noualhier coll. 1898), identified as Borborotrephes hedenborgi : 1 f ( MNHN). CAMEROON. Garoua, 2012, (Meyin), S. E. Meyin det. 2013: 1 f (SM); Yaoundé, 1975- 1986, (Gaétan Moller leg.), J. R. I. Ribeiro det. 2011: 1 f ( MNHN). IVORY COAST. Bouaké, 09.VIII.1969, [Ioc?], (D. Duviard “Rec.”), J. R. I. Ribeiro det. 2011: 1 f ( MNHN). DEMOCRATIC REPUBLIC OF CONGO. “ Congo Belge ”, [P.N.G.], Miss. H. de Saeger, [I/b/2”], 29.II.1950, [Réc. G. Demoulin.364], [with eggs on dorsum]: 1 m ( MRAC); [II/Je/13], 11-V-1951, Réc. P. Schoemaker 1782: 1 m ( MRAC); Katanga, Kapanga, V.1933, (G. F. Overlaet), [R. DET. 7123A, COLL. MUS. CONGO], J. R. I. Ribeiro det. in 2013: 2 f ( MRAC); Sandoa, XI.1931, (G. F. Overlaet) [R. DET. 7123A, “ MUSÉE DU CONGO ”]: 1 f ( MRAC); Tanganyika, Mpala, Oberthür, [“9898”], identified as L. fieberi by A. L. Montandon 1899, J. R. I. Ribeiro det. in 2011: 1 m ( MNHN). UGANDA. Victoria Nyanza, Ukerewe, VIII.1938, (R. P. Conrads) [R. DET. 7123, COLL. MUS. CONGO], J. R. I. Ribeiro det. in 2013: 1 f ( MRAC) [20]. CONGO. N. Rhodesia, [Kienge or Klenge?], 18.I.1938, (H. J. Brédo) [R. DET. 7123A, COLL. MUS. CONGO], J. R. I. Ribeiro det. in 2013: 1 m ( MRAC).

Distribution. Mabwe, Upemba ( Democratic Republic of Congo) ( Poisson 1954); Sudan, Egypt, Cameroon, central Africa, and Palestine; Brazzaville ( Congo) ( Stål 1854, Poisson 1967); Bangweulu Lake [as Région du Lac Bangweolo] (Samfya, Zambia), Région de la Kafubu (Lubumbashi, Democratic Republic of Congo) ( Poisson 1968a); Luanza (Kaluko River, Zambia) ( Poisson 1969). This species are herein newly recorded from Bouaké ( Ivory Coast), Kolda ( Senegal), and Victoria Nyanza ( Uganda).

Measurements (m / f): Total length (from apex of head to apex of abdomen at rest): 52.0–57.9 / 48.0–60.5; greatest width of body: 25.0–27.3 / 21.5–27.2.

General coloration. Almost uniformly brown. Body ovate with wings either covering or not covering abdomen.

Head, thorax, and abdomen. Pronotum with longitudinal median carina usually developed only on posterior portion ( Fig. 3 A, LMC); prosternal keel elongate and cylindrical, spiniform, usually robust, with apex truncate or obtuse ( Figs. 4 B–C), sometimes projecting anteriorly ( Fig. 4 B, BC). Pilosity poorly developed, covering almost half of connexivum (as Fig. 3 C), slightly constricted between spiracles, not extending posteriorly along genital operculum.

Male genitalia: Parameres symmetrical with distal section curved, directed upward, strongly curved near to apex, with small hook; length of phallotheca about 1.80 times ventral diverticulum in dorsal view; ventral diverticulum robust; dorsal arms of phallotheca directed parallel, not divergent, symmetrical, not connected or fused along basal portion, poorly associated with each other, U-shaped, rounded, not gradually narrowing at apex ( Fig. 3 D, DA); ventral diverticulum with anterior margins strongly sclerotized, broader, somewhat parallel posteriorly in ventral view ( Fig. 3 E, MVD); lateral outer margins of ventral diverticulum sinuous ( Fig. 3 E–F, LOM).

Taxonomic notes. Mayr (1871) and Linnavuori (1971) argued that L. hedenborgi does not seem to differ from L. fieberi in body shape. Based on Poisson’s (1949) study of external characteristics, L. fieberi can otherwise be distinguished from L. hedenborgi by (1) its female genital operculum rounded apically and (2) a slender body whose length is about 2.4 to 2.5 times its width in dorsal view. In fact, L. hedenborgi was also used as a valid name by Poisson (1947, 1949, 1952, 1954, 1968a, 1968b, 1969) and Poisson & de Sallier-Dupin (1970), even though they had neither seen Mayr’s specimens nor had any idea of its true specific identity. Conversely, according to Linnavuori (1971), L. fieberi has the female genital operculum variable in shape (especially at apex) in the Egyptian series, and the shape of male styli is also variable.

Members of this species may be mistakenly keyed out to L. expansum in Poisson’s (1949) key to Limnogeton species. In the key, the author distinguishes both L. expansum and L. scutellatum from the other species on the basis of body size, which is no more than twice the greatest width of body in these species. In addition, L. expansum is always 50.0 mm long whereas L. scutellatum is smaller than 50.0 mm. Nevertheless L. hedenborgi can be easily separated from other Limnogeton species by its aedeagal morphology, being the only Limnogeton species with robust, more rounded dorsal arms and having the ventral diverticulum with its lateral margins sinuous, in part because of its sclerotized borders are easily seen in ventral view ( Figs. 3 E–F).

In the Poisson’s (1949) key to African species, some L. fieberi specimens keyed out as L. hedenborgi , especially because of their body size. In addition, there is some variation in the prosternal carinae of female specimens from Egypt and Senegal, although this prosternal carina is always robust. A female from Senegal bears the prosternal carina slightly more curved than that of the female from Egypt ( Figs. 4 B–C), which is straight. Given that the prosternal carina in Limnogeton seems to be also linked to body size, a sexual size dimorphism in this genus might lead to some misunderstandings concerning reliable identifications both in L. fieberi and L. hedenborgi . It would therefore not be unlikely to identify some females of L. fieberi as L. hedenborgi , because females are usually bigger than males in Limnogeton (J.R.I. Ribeiro, unpubl. data), and have variable development of their prosternal carina. Despite this, the shape of prosternal carina in L. hedenborgi still seems to be distinctive enough to be used as a reliable characteristic distinguishing both species. Limnogeton hedenborgi specimens bear cylindrical prosternal keels, usually robust, with the apex truncate or obtuse ( Figs. 4 B–C), whereas L. fieberi specimens bear prosternal keels that are strongly spiniform, with the apex acute ( Fig. 2 B). We are consequently confident in not synonymizing these species.

Figures

FIGURE 2. Limnogeton fieberi Mayr, external morphology and male genital structures. 2 A, Dorsal habitus showing pronotum with longitudinal median carina. 2 B, Head showing prosternal carina, lateral view. 2 C – D, Male genital structures: 2 C, Dorsal apical membranous processes arising from phallotheca. 2 D, Ventral diverticulum of phallosoma showing anterior margins, ventral view. LMC, longitudinal median carina; MVD, margins of ventral diverticulum; PC, prosternal carina.

FIGURE 3. Limnogeton hedenborgi (Stål), external morphology and male genital structures. 3 A, Dorsal habitus showing pronotum with longitudinal median carina. 3 B, Head showing prosternal carina, lateral view. 3 C, Ventral aspect of abdomen showing poorly developed pilosity covering almost half of connexivum. 3 D – F, Male genital structures: 3 D, Dorsal apical membranous processes arising from phallotheca. 3 E – F, Ventral diverticulum of phallosoma showing anterior margins, ventral view. DA, dorsal arms of phallotheca; LMC, longitudinal median carina; LOM, lateral outer margins of ventral diverticulum; MVD, margins of ventral diverticulum; PC, prosternal carina; PIL, pilosity of connexivum.

FIGURE 4. Limnogeton hedenborgi (Stål), external morphology. 3 A, Dorsal habitus showing pronotum with longitudinal median carina. 3 B – C, Head showing prosternal carina, lateral view: 3 C, Female specimen from Egypt. 3 D, Female specimen from Senegal. LMC, longitudinal median carina; PC, prosternal carina.