Drosophila spinipes Lamb, 1914

Grimaldi, David A. & Jones, Lance E., 2020, A Revision of the Drosophila spinipes Species Group (Diptera: Drosophilidae), Zootaxa 4809 (1), pp. 1-28 : 8-10

Drosophila spinipes Lamb

Figs. 3 F–G, 4G, 5F, 7G

Drosophila spinipes Lamb, 1914: 336 .

Drosophila (Hirtodrosophila) spinipes Lamb : Tsacas, 1990.

Drosophila (Hirtodrosophila) suma Burla, 1954 : Tsacas, 2006 (as junior synonym).

Diagnosis: Thorax and head entirely light colored, a dark, dull, yellowish ochre, not dark black-brown or contrasting with legs and ventral pleura. Anterior reclinate midway between other two ipsilateral orbital setae; protarsomere 1 with 3 black, sclerotized spines (if present, spine no. 7 minute, unsclerotized), protarsomere 2 with 4 spines. Oviscapt uniquely with large terminal pegs and only 3 smaller pegs in ventral series. Male unknown.

Description: Coloration unique in group: light bodied, frons, face, mouthparts, scutum, scutellum, all of pleura dull, dark yellowish-ochre; abdominal tergites 2–5 with diffuse, darker markings, darkest on posterior margin of tergites, laterally diffuse. Setae, acrostichals reflect lighter than cuticle. Halter entirely light yellow. Costal spinules end ~0.3x distance from tips of R 2+3 and R 4+5. Protarsus with segment 1 slightly shorter than segment 2; with 7 black, heavily sclerotized spines, 4 on tarsomere 2, 3 spines on tarsomere 1 (spine 7 either absent or minute and not sclerotized), spine 8 slightly stouter than in other species. Oviscapt unique: apex truncate, pegs in dorsal triad and ventral pair in nearly a vertical row, these pegs significantly larger than ones in ventral series; apical notch deep, slight notch between ventral pair and ventral series, latter with only 3 small pegs. Measurements: Head: HD/HW 0.82; FL/LFW 1.41; EW/ED 0.71; OR2/OR1 0.81–0.88; OR3/OR1 1.09–0.94; OC/POC 1.50; FW/FD 0.62; ODB/ODA 0.52; Thorax: ThL mm.; UPS/LHS; LHS/ThL; ADC/PDC; AKE/PKE; LF1/LF2.

Holotype: None was designated by Lamb (1914), though specimen NHMUK 014335955 (described below) bears a small, round, red label “Type H.T.”, which may refer to “ holotype ”. Evenhuis (2007) gives a history of the BMNH practice of labeling specimens from an original syntype series, one as “ holotype ” and the others as “ paratype ”, as a wartime effort to sequester holotypes in a safe location outside London . Lectotype designations ideally should be made in the context of a revision. Regrettably, many entomologists studying the BM collections have mistakenly interpreted these syntypes as original holotypes and paratypes, as Evenhuis (2007) explains. NHMUK 014335955 is designated here as the lectotype .

Specimens Examined: Two specimens from the NHMUK were examined, both females and coming from two of the three localities in the Seychelles listed by Lamb (1914):

One, mounted with a minuten through a papered cork (handwritten “Praslin.48”) and through side of the thorax; minuten is corroded with crystalline raphides, otherwise the specimen is in relatively good condition with orbital and thoracic setae intact ( Figs. 3F , 4G ). Six labels, from top to bottom: a small, circular, blue-rimmed “ syntype ” label / a small, circular red-rimmed “Type H.T.” [? Holotype] label / “ Praslin ‘08, Seychelles Exp.” / “ Seychelles Is., Prof. J. S. Gardiner 1914-537” / small ID label “ D. spinipes Lamb [handwritten] TYPE” [the latter blue, printed, and glued onto it / dot matrix label: “ NHMUK 014335955 ”. Not dissected.

Second specimen is glued to its right side on small paper card (handwritten “36”), left wing missing, orbital setae intact but thoracic ones lost ( Fig. 3G ). Left tibia+tarsus and portion of abdomen removed and macerated by DG, stored in microvial on pin with specimen. Four labels from top to bottom: small, circular, blue-rimmed “ syntype ” / “Mahe 1908-9, Seychelles Exp.” / “ Seychelles Is., Prof. J. S. Gardiner, 1914-537, [handwritten] D. spinipes Lamb ” / dot matrix label: “ NHMUK 014335956 ” .

Comments: Lamb (1914) provided a description of the species that was far ahead of its time in detail. It was based on a series of 5 females that he reported had the head, palpi, thorax [scutum] and scutellum “orange”, and an arista with 3 dorsal branches (vs. the typical 2) plus the terminal fork. These features deviate from all continental Africa specimens, presumably why Burla (1954) decided that suma represented a different species. Our examination of two specimens from the series reveals that Lamb erred only with the number of aristal branches, which have the typical 2 dorsal ones.

Lamb (1914) mentioned specimens from three localities in the Seychelles: “Mahé, near Morne Blanc, X.1908 ”, “Silhouette: Mare aux Cochons, IX.1908 ”, and “Praslin: Côtes d’Or Estate, XI.1908.” Mahé is the largest, main island; the other two are considerably smaller, Silhouette ~ 25 km NW and Praslin ~ 35 km NE of Mahé. For geographical coordinates see the Appendix table .

In his identification of specimens from Natal, South Africa, Tsacas (1990) did not indicate how he distinguished D. spinipes from D. suma , and he later formally synonymized D. suma under D. spinipes ( Tsacas, 2006) . He must not have seen the NHMUK type series, which are immediately recognizable as distinct from the flies from Madagascar and continental Africa. Specimens in the Kwazulu-Natal Museum bear Tsacas’ identification labels, indicating that he dissected a male and female specimen from these ( Tsacas, 1990). Our study of these specimens and dissections and the undissected ones from Natal finds that they are D. phalloserra , n.sp.

Figures

FIGURE 3. Lateral and dorsal habitus of several Drosophila spinipes-group species. A. D. freidbergi n. sp. (HS-06). B. D. malagasy n. sp. (HS-18). C. D. nigrospinipes n. sp. (HS-24). D. D. phalloserra n. sp. (HS-08). E. Dorsal thorax, sp. C (HS-13). F. D. spinipes Lamb (NHMUK 014335955), dorsum. G. D. spinipes Lamb (NHMUK 014335956), lateral.

FIGURE 4. Photomicrographs, dorsolateral view, of the abdomen of several Drosophila spinipes-group species. A-C. D. malagasy n. sp. A.HS-16. B. HS-22. C. HS-18. D. D. nigrospinipes n. sp. (HS-24). E. D. phalloserra n. sp. (HS-07). F. D. suma Burla (HS-01). G. D. spinipes Lamb (NHMUK 014335955).