Rhagiosoma madagascariense ( Heyden, 1877 ) Sekerka, 2007

Sekerka, Lukáš, 2007, On the genus Rhagiosoma and the identity of R. madagascariense (Coleoptera: Chrysomelidae: Sagrinae: Megamerini), Acta Entomologica Musei Nationalis Pragae 47, pp. 195-202 : 198-200

Rhagiosoma madagascariense ( Heyden, 1877) comb. nov. & stat. restit.

( Figs. 3 a-c)

Mecynodera madagascariensis Heyden, 1877: 105 . Rhagiosoma madagascariense Chapuis : REINECK (1913): 303 (incl. genitalia), misidentification.

Type locality. ‘Nossi-Bé. Madagascar’ [= Nossi Bé Island NW of Madagascar].

Type material. LECTOTYPE (designated here): J, ‘Nossi-Bé. [w, hw, h] / Mecynodera / madagascariensis [w, hw, h]’ ( ZMHB) . PARALECTOTYPES: J, ‘ Fauna / Ins. Nossibé. [w, p, s] // madagascariensis / [w, hw, s] // Coll. / B. Schwarzer [w, p, h] // Senckenberg- / Museum / Frankfurt / Main [w, p, h]’ ( SMF) ; J, ‘ Nossibé / 96.70 [w, hw, s] // Mecynodera / madagascariensis / Nossibé [w, hw, s]’ ( BMNH) ; J, ‘ Fauna / Ins.Nossibé. [w, p, s] // Mecynodera / madagascariensis / Nossibé [w, hw, s] // Coll. Kraatz [w, p, h] // coll. DEI / Müncheberg [w, p, h]’ ( DEI). The specimens are provided with the following label : ‘ LECTOTYPUS [or PARALECTOTYPUS] / Mecynodera / madagascariensis / Heyden, 1877 / L. Sekerka des. 2007 [red, p, bb, h]’.

Additional material examined. MADAGASCAR: Nossi-bé , 2 JJ 1♀, without additional data ( ZMHB) ; Ins. Nossibé , 1J, without additional data ( DEI) ; Nossibé , 2 JJ 1 ♀, without additional data ( BMNH) ; Nossi-bé , 1885, 5 JJ, Stumpff ( SMF) .

Differential diagnosis. Rhagiosoma madagascariense is very similar to R. chapuisi nom. nov. and R. grossum Reineck, 1913. Rhagiosoma grossum distinctly differs from both species in a stouter and larger body (length/width body ratio in R. grossum : males below 3.15 and females below 2.50; in R. madagascariense : males over 3.20 and females over 2.60); distinctly more convex body, more convergent elytra (converging from 1/3 of the length), well-marked elytral punctuation and striae, and punctures with distinct fovea. On the other hand, R. madagascariense and R. chapuisi nom. nov. have elytra almost parallel-sided and converging only near apex, only slightly convex on the disc, and smooth surface without distinct foveae at punctures and without impressed striae.

The latter two species are extremely close and can be reliably identified only by the structure of the aedaeagus. The aedaeagus of R. chapuisi is distinctly stouter and larger with a more curved lobe and without deep sulci ( Figs. 3a,b ). The aedaeagus of R. madagascariense has a nearly straight lobe and distinct sulci stretching from apex to half length of the tube ( Figs. 2a,b ); the parameres have a deep basal sulcus ( Fig. 2c ) and a deeper cleft than in R. chapuisi ( Fig. 3c ).

However, it is also possible to distinguish the two species by some external morphological characters. Rhagiosoma madagascariense is somewhat less arched with elytral plate rather depressed, and has a dull pronotum with irregular punctuation, several wrinkles, and a smooth and impunctate medial area extended from the base to the anterior margin. The pronotum of R. chapuisi is stouter with somewhat elevated anterior margin, shiny and nearly regularly punctate without wrinkles.

Distribution. Madagascar, Antsiranana province, Nossi-bé Island.

Comments. Mecynodera madagascariensis was described from Nossi-bé Island ( HEYDEN 1877) and was omitted in all catalogues and papers until MONRÓS (1958) cited it, without any comments, as a synonym of R. madagascariense . Even in his revision of the genus Megamerus, MONRÓS (1956) pointed out only the occurrence of Mecynodera Hope, 1840 , in Madagascar without any additional data.

Both species are very close, and R. madagascariense may represent only an insular form of R. chapuisi . Besides types, I have seen only limited material of R. madagascariense . All examined specimens show constant morphology in both species, thus both are treated as valid. It is necessary to examine more material from various Madagascan localities to verify their status.

The number of available specimens and deposition of type(s) was not mentioned in the original description of M. madagascariensis by HEYDEN (1877). Heyden’s collection is spread among several museums and institutions. According to L. Zerche (2006, pers. comm.), DEI houses mainly the Palaearctic part of Heyden’s collection and exotic specimens are deposited in SMF. I found a total of four specimens bearing the identification label ‘ Mecynodera madagascariensis ’. Their labels are handwritten by Heyden and they are deposited in museums which contain parts of his collection. These facts lead me to suppose that with great probability they belong to syntypes, and I designate them as lectotype and paralectotypes.

Figures of genitalia given in REINECK (1913) correspond with R. madagascariense and not with R. chapuisi . I have examined several specimens with locality ‘Nossi-bé’ dissected by Reineck (deposited at ZMHB) and confirm that they belong to R. chapuisi .

Figures

Figs. 1-3. 1 – Megamerus kingi MacLeay, 1827; 2 – Rhagiosoma madagascariense (Heyden, 1877); 3 – R. chapuisi nom. nov.; a – aedeagus, dorsal view; b – aedeagus, lateral view; c – parameres, dorsal view.