Drosophila tsacasi, Bock & Wheeler, 1972

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 : 17

‘ D. tsacasi species complex’ new complex

Figs 1–2 , 3B

Diagnosis

Male abdominal tergites T2–T5 yellowish with usually distinct black stripes, T6 usually black; cercal ventral lobe (secondary clasper) fused to cerci with four or five very large curved black medial teeth arising from long dark chitinous roots on the internal margin; surstylus lobate with a lateral row of long, irregularly spaced prensisetae on the outer margin and a cluster of prensisetae on the inner margins (no medial prensisetae), the innermost one significantly long ( Fig. 3B ). Female abdominal tergites lighter than male’s or concolorously light.

Remarks

This complex contains two described species, D. tsacasi and D. seguyiana , and two putatively new species, D. aff. tsacasi (see above under D. curta ) and D. aff. bakoue (see above under D. bakoue ). The molecular, morphological and reproductive isolation between these species requires further investigation.

Taxon content

D. tsacasi Bock & Wheeler, 1972 .

D. seguyiana Chassagnard & Tsacas, 1997 .

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.