Macrosiagon elegans ( Marseul, 1876 )

Batelka, Jan, 2010, A review of Ripiphoridae in the Arabian Peninsula (Coleoptera: Tenebrionoidea), Acta Entomologica Musei Nationalis Pragae 50 (1), pp. 157-166 : 159

Macrosiagon elegans ( Marseul, 1876)

( Figs. 1–9 , 18 )

Published records. MARSEUL (1876: 27) (as Rhipiphorus elegans ): ‘Arabie, Djeddah, TYPE’. BATELKA (2007: 242): ‘S. Arabia, Jidda, 1 ♀, LECTOTYPE’.

New records. ‘ARABIA’: 1 ♀ ( BMNH), ‘Arabia [hw] // F. Bates / 81 – 19 [p, form A, det. K.G. Blair]’. SAUDI ARABIA: 1 J 1 ♀ ( BMNH), ‘Arabia: / Hejaz, / Jidda. [p] / 4.xii. [hw] 1926. / H. St. J. B. Philby. [p] // Brit. Mus. / 1927 – 30. [p, form B + C, det. K.G. Blair]’. YEMEN: 1 ♀ ( BMNH), ‘4049 // Millin / gen // Arabia / Yemen [hw] // Fry Coll. / 1905. 100 [p] // Rhipiphorus / elegans Mars [hw] / det. K.G.B. [p, form A, det. K.G. Blair] ’; 1 ♀ ( BMNH), ‘4048 // Millin / gen // Arabia / Yemen [hw] // Fry Coll. / 1905. 100 [p] // form / B [hw, det. K.G. Blair] ’.

Variability. Two female forms could be distinguished in the available specimens. Form A ( Figs. 5–8 ) sensu K. G. Blair (see New records) is represented by typically coloured females with a completely orange body except of the black metepimeron and two black spots on each elytron, one isolated in the middle and one small at the apex. Female form B ( Figs. 1–4 ) is light red with black middle and hind legs and a black mesepisternum, metepimeron, mesepimeron, metepisternum and metaventrite. The elytra are orange with a black basal band, isolated central spot and black apical spot. The length of metatarsomeres is also different: form A has the 2 nd metatarsomere short and robust (but not flattened from above as in M. bipunctata ) and shorter than the 3 rd ( Figs. 6–7 ). Form B has the 2 nd metatarsomere long and slender and almost as long as the 3 rd ( Figs. 2–3 ). Moreover, the species is quite variable in the shape of the elevated process at the apex of pronotum: in form A it is quite distinct and long ( Fig. 8 ), while in form B it is reduced with a small cavity ( Fig. 4 ). Both forms are 6–10 mm long and overlap in their range of distribution. I assume that the morphological and colour differences between both forms are related to their development (possibly different hosts?) and have no taxonomic value. Form C ( Fig. 9 ) is a 4 mm long male, which is completely black with light yellow, basally and apically black elytra (sexual dichroism) and fuscous antennae and tarsal segments; the elevated process at the apex of pronotum is reduced with a small cavity.

Biogeography. Macrosiagon elegans belongs to the rather speciose M. ‘ bifasciata ’ species group ( BATELKA 2008b), to which also belongs M. fortieri (Chobaut, 1893) described from Egypt. Macrosiagon elegans seems to be more closely related to M. bifasciata (an Eastern Palaearctic and Oriental species) or to M. meridionalis (Costa, 1859) (a Mediterranean species) than to M. bipunctata (with which it occurs sympatrically in Yemen) or to M. fortieri . However, these affinities cannot be proved without a comparison of molecular data of all related species.

Distribution. Eritrea, Saudi Arabia, Yemen (new country record).

Figures

Figs. 1–8. Macrosiagon elegans (Marseul, 1876). 1–4 – female form ‘B’ from Yemen; 5–8 – female form ‘A’ from ‘Arabia’. Not to scale.

Figs. 9–14. Arabian Macrosiagon. 9 – M. elegans (Marseul, 1876), male; 10 – M. bipunctata (Fabricius, 1801), female from Dhawran; 11 – M. ferruginea (Fabricius, 1775), female from Jebel Jibir; 12 – M. oberthurii (Fairmaire, 1879), female from Bahrain; 13–14 – M. terminata (Laporte, 1840), females, two colour forms from Wadi Wurayah. Not to scale.

Fig. 18. Distribution of the Ripiphoridae in the Arabian Peninsula.