Drosophila seguyi, Smart, 1945

Yassin, Amir, Suwalski, Arnaud & Raveloson Ravaomanarivo, Lala H., 2019, Resolving the synonymy and polyphyly of the ‘ Drosophila bakoue species complex’ (Diptera: Drosophilidae: ‘ D. montium species group’) with descriptions of two new species from Madagascar, European Journal of Taxonomy 532, pp. 1-26 : 9

‘ D. seguyi species complex’ Lachaise, 1971

Figs 1–2 , 3A , 4 , 5 E–F, 6

‘ D. seguyi species complex’ Lachaise, 1971: 1623.

‘ D. bakoue species complex’ Rafael, 1984: 179, syn. nov.

Diagnosis

Male abdominal tergites T2 to T4 yellowish with very distinct black stripes or entirely dark brown, T5 with broader stripe or completely black, T6 shiny black ( Fig. 4 ); cercal ventral lobe (secondary clasper) fused to cerci with two or three very large curved black medial teeth on the internal margin; surstylus quadrate with a lateral row of strong, short prensisetae on the outer and inner margins (with two medial prensisetae in D. chocolata sp. nov.), the innermost one significantly long; hypandrial median process tapering; aedeagus hirsute with fine cuticular scales; posterior parameres as long as aedeagus (slightly shorter in D. chocolata sp. nov.), with finely serrated margins ( Figs 3A , 5 ). Female abdominal tergites lighter than male’s or concolorously dark ( Fig. 4 ).

Remarks

The original ‘ D. seguyi species complex’ was renamed ‘ D. bakoue species complex’ without new definition or justification ( Rafael 1984). We consider here the ‘ D. bakoue species complex’ to be a junior synonym for the ‘ D. seguyi species complex’. Chassagnard et al. (1997) discussed a ‘ D. seguyi species complex’ comprising D. curta , D. seguyi and D. seguyiana in a table legend, but considered all these species members of the ‘ D. bakoue species complex’ in the main text. We restrict here the ‘ D. seguyi species complex’ to four monophyletic species, while placing D. seguyiana in the ‘ D. tsacasi species complex’ (see below). David et al. (2014) referred to three of these species as geographical strains of D. malagassya with partial reproductive isolation. Closer examination of their material revealed, however, that each strain was a distinct species (namely, D. seguyi , D. malagassya and D. curta ).

Taxon content

D. seguyi Smart, 1945 .

D. malagassya Tsacas & Rafael, 1982 .

D. curta Chassagnard & Tsacas, 1997 .

D. chocolata sp. nov.

Figures

Fig. 1. Bayesian phylogeny of 19 species from the ‘D. montium species group’ Da Lage, 2007 inferred from complete mitochondrial genomes. Nodes supported by 100% posterior probability (pp) are not labeled, those with pp> 90% or 60% are labeled with gray and white circles, respectively. Species belonging to the ‘D. bocqueti species complex’ and the ‘D. bakoue species complex’ are highlighted in orange and green, respectively. ‘K’ and ‘B’ refer to the strains of D. aff tsacasi Bock & Wheeler, 1972 from Kenya and Bioko Island, respectively.

Fig. 2. Comparison of Bayesian phylogenies of the ‘D. seguyi species subgroup’ Yassin, 2018 inferred from mitochondrial COI (left) and nuclear Amyrel (right) genes. Nodes supported by>95% posterior probability (pp) are labeled with black circles. An asterisk refers to species sequenced here, whereas two asterisks refer to the sequence of D. vulcana Graber, 1957 of Da Lage et al. (2007), which turned out to belong to D. seguyi Smart, 1945 from Kenya (see the text). Note the discrepancy in position of different geographical strains of D. bakoue Tsacas & Lachaise, 1974 (in red) between the two genes. Species belonging to ‘D. bocqueti species complex’ Tsacas & Lachaise, 1974, ‘D. bakoue species complex’ Rafael, 1984, ‘D. nikananu species complex’ Tsacas & Chassagnard, 1992, and ‘D. megapyga species complex’ Lachaise & Tsacas, 2001 are highlighted in orange, green, yellow and red, respectively.

Fig. 3. Photomicrographs of male periphallic organs. A. D. seguyi Smart, 1945 (MNHN). B. D. aff. tsacasi Bock & Wheeler, 1972 (MNHN). C. D. mylenae David & Yassin sp. nov. (MNHN). Scale bars = 0.1 mm.

Fig. 4. Adult habitus. A–B. D. seguyi Smart, 1945 (MNHN). A. ♂. B. ♀. C–D. D. malagassya Tsacas & Rafael, 1982 (MNHN). C. ♂. D. ♀. E–F. D. curta Chassagnard & Tsacas, 1997 (MNHN). E. ♂. F. ♀. G–H. D. chocolata Yassin & David sp. nov. (MNHN). G. ♂. H. ♀. Only dark morphs of females of species with female-limited color dimorphism are shown. Scale bar = 1 mm.

Fig. 5. Male terminalia of the ‘D. seguyi species complex’. A. D. seguyi Smart, 1945 (MNHN). B. D. malagassya Tsacas & Rafael, 1982 (MNHN). C. D. curta Chassagnard & Tsacas, 1997 (MNHN). D–F. D. chocolata Yassin & David sp. nov. Scale bars: A–D = 50 µm; E–F = 100 µm..