Drosophila (Sophophora) chocolata Yassin & David, 2019

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 : 15-16

Drosophila (Sophophora) chocolata Yassin & David sp. nov.

urn:lsid:zoobank.org:act:F34BF7C9-1143-4093-80E5-47A239D5C86C

Figs 1–2 , 4 G–H, 5D–F, 6G–H

Diagnosis

Male and female body pigmentation brown, halters white, with male femurs darker on all legs ( Fig. 4 G– H); male abdominal tergites T2–T4 entirely dark brown, T5 and T6 entirely black ( Fig. 4G ); dorsalmost surstylus prensiseta on the same axis with remaining prensisetae ( Fig. 5 D–E); hypandrial median process lobate; aedeagus spatulate ( Fig. 5D, F ); female T2–T7 entirely dark brown ( Fig. 4H ); oviscapt fourth posterior peg-like outer ovisensillum not on the same axis with the third and fifth ovisensilla ( Fig. 6G ), with anterior ovisensilla short and thick ( Fig. 6H ).

Etimology

In reference to body color.

Type material

Holotype

MADAGASCAR • ♂; Andasibe ; 17°20′ S, 48°54′ E; 16–17 Feb. 2008 (ex-laboratory strain Jul. 2014); J.R. David & A. Yassin leg.; MNHN.

Paratypes

MADAGASCAR • 9 ♂♂, 10 ♀♀; same collection data as for holotype; MNHN .

Other material

MADAGASCAR • 5 ♂♂, 2 ♀♀; same collection data as for holotype; ZUAC .

Description

Male

HEAD ( Fig. 4G ). Frons brown, frontal length 0.38 mm; frontal index = 1.00, frontal tapering ratio = 1.47. Frontal triangle concolorous; ocellar triangle slightly darker, about 40% of frontal length. Orbital plates shining, apically slightly diverging from eye margin, about 87% of frontal length. Orbital setae black, distance of or3 to or1 = 67% of or3 to vtm, or1/or3 ratio = 1.29, or2/or1 ratio = 0.33, postocellar setae = 73%, ocellar setae = 47%, vibrissal index = 1.00. Face grayish. Carina flat. Cheek index about 12.50. Eye dark red, eye index = 1.39. Antennae dark brown. Arista with five dorsal, two ventral branches, plus terminal fork. Proboscis brown.

THORAX ( Fig. 4G ). Length 1.2 mm. Scutum brown, shining, darker before scutellum and having a darker median stripe on dorsocentral region, six rows of acrostichal setulae. H index = 0.50. Transverse distance of dorsocentral setae 160% of longitudinal distance; dc index = 0.88. Scutellum dark brown; scut index = 0.83. Pleura dark brown, shining. Legs dark brown, sex combs on protarsomeres 1 and 2, with about 21 and 16 peg-like setae, respectively. Wing hyaline, veins reddish, length 2.02 mm, length to width ratio = 2.18. Indices: C = 2.20, ac = 2.46, hb = 0.52, 4C = 1.88, 4v = 3.68, 5x = 0.61, M = 1.38, prox. x = 0.94. Haltere white.

ABDOMEN ( Fig. 4G ). Entirely brown, shining, tergites T5 and T6 completely black.

TERMINALIA ( Figs. 5 D–F). Epandrium black, with six setae, the lower most being particularly long; epandrial ventral lobe black with eight bristles. Cercus black; cercal ventral lobe yellow, partially separated from cercus, with a series of three strong, curved spines on the inner margin, and smaller spines along the ventral, outer and dorsal margins, larger dorsally. Surstylus with a regular row of five short, stout peg-like prensisetae, and a ventromedial cluster of prensisetae, the innermost pointing dorsally. Hypandrium black anteriorly, dark posteriorly, as long as broad, with a lobate medial posterior extension bearing two short, divergent thick bristles; posterior margin microtrichose with long fine hairs. Outer paraphyses large, S-curved, transverse, bearing three minute setulae. Inner paraphyses as long as aedeagus, swollen medially, broad and lobate apically. Aedeagus broad, hirsute, subapically narrowed. Aedeagal apodeme black anteriorly.

Female

HABITUS ( Fig. 4H ). Similar to male but with no sex combs on protarsi.

TERMINALIA ( Fig. 6 G–H). Valve of oviscapt mediodorsally mostly membranous, posteriorly rounded, ventrally slightly concave, with no discal and twelve marginal, peg-like, pointed-tipped, short and thick ovisensilla on the outer surface and one long, straight, subterminal and three tiny (microscopic) trichoid-like ovisensilla on the inner surface. The fourth peg-like ovisensillum characteristically dorsally positioned in respect to the main axis of ovisensilla insertion on the ventral margin of the oviscapt valve.

Distribution

Madagascar (endemic).

Remarks

Specimens of this species were collected from different localities in Madagascar:Andasibe (800–1200 m a.s.l.), Antananarivo (1300 m a.s.l.) and Mandraka (1400 m a.s.l.) during the 2008 expedition by J.R. David and A. Yassin. It was also collected from Ranomafana (600 m a.s.l.) in 2009 by J.R. David, V. Debat and A. Yassin. This indicates that D. chocolata sp. nov. is widespread and that, unlike D. ifestia Tsacas, 1984 , is not mountainous. The species can be maintained on a ‘standard Drosophila medium’ in the laboratory.A mutant strain from Antananarivo was established having a light abdomen in both sexes, but both the mutant and the original strains were subsequently lost.

The species resembles D. ifestia , a species endemic to high mountains in East Africa, in males having entirely dark abdomen. However, D. ifestia differs from D. chocolata sp. nov. in the color of the thorax being lighter with the halters reddish brown ( Fig. 7 A–B), which are white in D. chocolata sp. nov. ( Fig. 6 A–B), in the lack of long innermost prensiseta on the surstylus (present in all species of the ‘ D. seguyi species complex’), and in the shape of the hypandrial median process being broadly truncated in D. ifestia with the hypandrial bristles extending in parallel to each other (divergent in all species of the ‘ D. seguyi species complex’). We therefore concur with the conclusion of Tsacas (1984) that D. ifestia does not belong to any of the defined species complexes of the ‘ D. seguyi species subgroup’.

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. 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..

Fig. 6. Female oviscapts of the ‘D. seguyi species complex’. A–B. D. seguyi Smart, 1945 (MNHN). C–D. D. malagassya Tsacas & Rafael, 1982 (MNHN). E–F. D. curta Chassagnard & Tsacas, 1997 (MNHN). G–H. D. chocolata Yassin & David sp. nov. (MNHN). Scale bars: A, C, E, G = 100 µm; B, D, F, H = 50 µm.

Fig. 7. Photomicrographs of D. ifestia Tsacas, 1984. A. Holotype (P. Vanschuytbroeck and J. Kelenbosch leg.; MNHN). B. Paratype (P. Vanschuytbroeck and J. Kelenbosch leg.; MNHN). Scale bar = 1 mm.