Drosophila (Sophophora) mylenae David & Yassin, 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 : 21-22
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|Drosophila (Sophophora) mylenae David & Yassin|
Male abdominal tergites T5 and T6 with a distinct dark brown stripe expanding in the middle and fainting towards the margins ( Fig. 8B View Fig ); hypandrium broad with a short anterior phragma; outer paraphases posterior margin not curved; aedeagus pilosity broad at tip ( Fig. 9B, D View Fig ); female abdominal tergites T2–T4 with a diffuse pale region on the antero-distal margins, T5 with distinct dark stripe ( Fig. 8D View Fig ); oviscapt fourth posterior peg-like outer ovisensillum on the same axis with the third and fifth ovisensilla, with anterior ovisensilla short and thick ( Fig. 9F View Fig ).
A species dedicated to Mylène Dauvergne, co-collector of the type strain.
MADAGASCAR • 9 ♂♂, 10 ♀♀; same collection data as for holotype; MNHN GoogleMaps .
MADAGASCAR • 5 ♂♂, 5 ♀♀; same collection data as for holotype; ZUAC GoogleMaps .
HEAD ( Fig. 8C View Fig ). Frons pale brown, frontal length 0.35 mm; frontal index = 1.00, frontal tapering ratio = 1.29. Frontal triangle concolorous; ocellar triangle slightly darker, about 43% of frontal length. Orbital plates about 86% of frontal length. Orbital setae black, distance of or3 to or1 = 50% of or3 to vtm, or1 / or3 ratio = 1.33, or2/or1 ratio = 0.38, postocellar setae = 29%, ocellar setae = 50%, vibrissal index = 1.00. Face white. Carina prominent, narrow. Cheek index about 12.00. Eye red, eye index = 1.15. Antennae whitish. Arista with four dorsal, three ventral branches, plus terminal fork. Proboscis brown.
THORAX ( Fig. 8C View Fig ). Length 1.13 mm. Scutum mid brown, shining, darker before scutellum, six rows of acrostichal setulae. H index = 1.17. Transverse distance of dorsocentral setae 200% of longitudinal distance; dc index = 0.61. Scutellum dark; scut index = 0.80. Pleura slightly darker, shining. Legs whiteyellow, sex combs on protarsomeres 1 and 2, with about 18 and 13 peg-like setae, respectively. Wing dark, length 1.54 mm, length to width ratio = 2.08. Indices: C = 1.93, ac = 3.06, hb = 0.62, 4C = 1.72, 4v = 3.03, 5x = 0.56, M = 1.13, prox. x = 0.72. Haltere brown.
ABDOMEN ( Fig. 8C View Fig ). Yellow, tergites T2–T4 with a diffuse brown posterior stripes, tergites T5 and T6 pale with small posterior stripes.
TERMINALIA ( Figs 3C View Fig , 9B, D View Fig ). Epandrium pale brown, with 6 setae, the lower most being particularly long; ventral lobe with 5–7 bristles. Cercus pale brown; 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 yellow, slightly longer than broad, with a pointed medial posterior extension bearing two short, divergent thick bristles; posterior margin microtrichose with long fine hairs. Outer paraphyses large, ovoid, transverse, bearing three minute setulae. Inner paraphyses almost as long as aedeagus, swollen medially, tapering and incurved medioposteriorly. Aedeagus hirsute, broad at tip, subapically narrowed. Aedeagal apodeme yellow, broadened laterally.
HABITUS ( Fig. 8D View Fig ). Similar to male, but with no sex combs on protarsi and with abdominal tergites brown.
TERMINALIA ( Fig. 9F View Fig ). 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) trichoidlike ovisensilla on the inner surface.
Drosophila mylenae sp. nov. resembles D. vulcana in the shape of the male periphallic structures (compare Fig. 3C View Fig with figure 1 in Rafael 1984) and the female ovipositor ( Fig. 9 View Fig E–F) as well as in the abdominal pigmentation pattern of females being darker than males ( Fig. 8 View Fig ), which is rare among drosophilids. However, they differ in the degree of abdominal pigmentation for both sexes and in multiple phallic structures ( Figs 8–9 View Fig View Fig A–D). The two species show a very low mitogenomic divergence of 0.5% ( Figs 1–2 View Fig View Fig ). However, on the nuclear gene Amyrel they are quite distinct ( Fig. 2 View Fig ), with an overall nuclear genome-wide divergence of 2.35% (Yassin, in prep.).
Drosophila mylenae sp. nov. was only collected in the littoral forest on Nosy Be. It is absent from material collected from the inland, humid forests of Madagascar, i.e., Antananarivo, Mandraka, Andasibe and Ranomafana. It is also absent from Mayotte or other islands of the Western Indian Ocean. Females do not exhibit a sex-limited color dimorphism.
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