Wing measures of 97 species of Drosophilidae (Diptera) photographed by Duda in 1924

The taxonomy of the
Drosophilidae of New Guinea requires detailed knowledge of the fauna of
neighbouring regions to the south (Australia), the east (islands of the South
Pacific), the west (Indonesia) and the northwest (Philippines). The majority of
species known from Indonesia were collected on Java and Sumatra by Jacobson in
the period 1906–1929; he deposited all his specimens in Dutch museums and they are
now at Naturalis in Leiden. De Meijere and Duda worked independently on this
material in the first decades of the twentieth century and between them
described most of it. Since then very little taxonomic research has focused on
the drosophilid fauna of this part of the world. Duda (1924) published
photographs of the wings of 103 fly species including 48 drosophilids from Southeast
Asia (mainly Java and Sumatra). The venation, visible in each photo, has now
been measured and tabulated here (Table 1). It is known that wing venation is variable
between, but not significantly within, species and therefore provides a useful
diagnostic tool. Diagnostic success is greatly enhanced when comparative
analysis involves many metrics screened simultaneously. About seven standard
wing indexes that describe ratios of vein lengths and sections (e.g., C, 4v, 4c,
M, 5x, hb, prox.x, etc., see Table 2) are available for almost all drosophilids
described since the 1950s. Standard measure-points or landmarks of the
drosophilid wing are given by McEvey (2017). Datasets of wing indexes can be
assembled from the literature. It is possible to interrogate such datasets with
the measurements of an unknown taxon to produce a shortlist of one or several
taxa that are possibly conspecific. The tables presented here list the wing
indexes of all 103 species pictured by Duda (1924), many of them are given here
for the first time. These metrics can be appended to available datasets greatly
facilitating research on the largely undescribed drosophilid fauna of New
Guinea.
Table 1. Wing measures based on 104 fly
wing photos published by Duda (1924, Arch.
Naturgesch. 90(A3): 172–234). Heavy setation in the third costal section is
not visible and could not be measured; in several instances dark wings obscured
venation; Duda’s original 1924 figure captions are given as well as the
currently valid name (Taxon); all photos are at the same scale (Vergrößerung einheitlich), wing length
(WL) in the D. melanogaster photo (Fig. 82) is, from other data, 1.63 mm
and so magnification factor is 18 not 11 as stated by Duda. SEA = present in
southeast Asia; * see Brake & Bächli (2008, Drosophilidae (Diptera).
World Catalogue of Insects).
Table 2. Key to abbreviations for wing
measures and indexes used in Table 1; a vein or vein-section length is the
distance between two measure-points or landmarks (see labelled diagrams of
measure-points in McEvey, 2017).