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
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|Drosophila (Sophophora) chocolata Yassin & David|
Male and female body pigmentation brown, halters white, with male femurs darker on all legs ( Fig. 4 View Fig G– H); male abdominal tergites T2–T4 entirely dark brown, T5 and T6 entirely black ( Fig. 4G View Fig ); dorsalmost surstylus prensiseta on the same axis with remaining prensisetae ( Fig. 5 View Fig D–E); hypandrial median process lobate; aedeagus spatulate ( Fig. 5D, F View Fig ); female T2–T7 entirely dark brown ( Fig. 4H View Fig ); oviscapt fourth posterior peg-like outer ovisensillum not on the same axis with the third and fifth ovisensilla ( Fig. 6G View Fig ), with anterior ovisensilla short and thick ( Fig. 6H View Fig ).
In reference to body color.
MADAGASCAR • 9 ♂♂, 10 ♀♀; same collection data as for holotype; MNHN GoogleMaps .
MADAGASCAR • 5 ♂♂, 2 ♀♀; same collection data as for holotype; ZUAC GoogleMaps .
HEAD ( Fig. 4G View Fig ). 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 View Fig ). 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 View Fig ). Entirely brown, shining, tergites T5 and T6 completely black.
TERMINALIA ( Figs. 5 View Fig 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.
HABITUS ( Fig. 4H View Fig ). Similar to male but with no sex combs on protarsi.
TERMINALIA ( Fig. 6 View Fig 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.
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 View Fig A–B), which are white in D. chocolata sp. nov. ( Fig. 6 View Fig 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’.
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