Research Article |
Corresponding author: Hans R. Feijen ( hans.feijen@naturalis.nl ) Academic editor: Rudolf Meier
© 2021 Hans R. Feijen, Frida A. A. Feijen, Cobi Feijen, Benoît Gilles.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Feijen HR, Feijen FAA, Feijen C, Gilles B (2021) A review of Madagopsina Feijen, Feijen & Feijen (Diptera, Diopsidae) with description of a new species, key to the species, and discussion of intrageneric relationships. ZooKeys 1057: 1-21. https://doi.org/10.3897/zookeys.1057.67433
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For the recently established genus Madagopsina (Diopsidae, stalk-eyed flies), Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov. is described from Madagascar. A concise catalogue is given for the genus and an identification key is presented for its six species. The differential character states are listed for the two species groups of the genus: the Madagopsina apollo species group and the Madagopsina apographica species group. The intrageneric relations are discussed based on morphology, geometric morphometrics analysis of wing shape, and allometric data for eye span against body length. Each of these three procedures places the new species in the M. apollo species group with Madagopsina parvapollina as its closest relative. New records are presented for M. apographica and M. parvapollina.
Allometry, catalogue, Madagascar, stalk-eyed flies, wing morphometry
In 2018, Feijen et al. erected Madagopsina Feijen, Feijen & Feijen and Gracilopsina Feijen, Feijen & Feijen as endemic genera for Madagascar. These new genera were placed in a Diopsidae clade with irrorated wings, named the Teleopsis genus group. In Madagopsina, two earlier described species were placed: Diopsis apollo Brunetti and Diopsis (Eurydiopsis) apographica Séguy. In addition, three new species were described for Madagopsina: M. freidbergi, M. parvapollina, and M. tschirnhausi. Shortly after the 2018 publication, a single specimen of Madagopsina was received which turned out to be an undescribed species. This species is described herein. In Madagopsina, two species groups were distinguished by
The description of M. makayensis Feijen, Feijen & Feijen, sp. nov. is based on a single male specimen that was preserved in alcohol. The holotype is now pinned with the genitalia placed in a genitalia tube attached to the pin. Some additional records for Madagopsina became known via photographs placed on www.iNaturalist.org. For the rate of dimorphism D, the difference between males and females in allometric slope for eye span on body length is used in the Diopsidae (
AU Approximately Unbiased p-value,
BP Bootstrap Probability values,
D Rate of Dimorphism,
SE Standard Error.
Diopsidae Billberg, 1820: 115 (as Natio Diopsides). Type genus: Diopsis Linnaeus, 1775: 5.
Madagopsina Feijen, Feijen & Feijen, 2018:145. Type species Diopsis apollo Brunetti, 1928.
Eurydiopsis
sensu Séguy & Vanschuytbroeck (nec Frey) - in part;
A concise catalogue for the genus is given below. For details on the type series, records, and combinations to various other genera of the earlier described species can be referred to
Diopsis (Eurydiopsis) apographicus Séguy, 1949: 69.
Eurydiopsis anjahanaribei Vanschuytbroeck, 1965: 336.
Madagopsina apographica;
Madagascar, 1 ♀, Fianarantsoa, Vatovavy, Fitovinany, Ifanadiana, 21°15'34"S, 47°24'55"E, 977 m, 7.xi.2014, lemurtaquin, (ref. www.inaturalist.org/observations/36199753); 1 ?sex (probably ♀), Antsiranana, Sava, Sambava, rainforest, 14°26'60"S, 49°43'10"E, 1310 m, 30.x.2016, Éric Mathieu (ref. www.inaturalist.org/observations/69807405). The new records fall well within the eastern forests distribution as indicated in
Diopsis apollo Brunetti, 1928: 280.
Madagopsina apollo;
Madagopsina freidbergi
Madagopsina parvapollina
Madagascar, 1 ♂, Mahajanga, Boeny, 16°24'44"S, 45°18'48"E, 123 m, 23.x.2016, Gernot Kunz (ref. www.inaturalist.org/observations/20766277); 1 ?sex (probably ♂), Mahajanga, Boeny, Soalala, 16°26'4"S, 45°21'20"E, 138 m, Josiane Lips, Olivier Testa (ref. www.inaturalist.org/observations/37503778 and www.inaturalist.org/observations/37503777), the photograph formed part of a batch made during a caving expedition in Namoroka caves, while all pictures were taken in caves or at the entrance; 1 ♂ Makay, canyon, sous-bois, rive d’une rivière [undergrowth, riverbank], 21°10'11"S, 45°22'15"E, 528 m, 30.vii–3.viii.2017, leg. Benoît Gilles. The new records fall well within the western forests distribution as indicated in
Madagopsina parvapollina, live photographs by Gernot Kunz, Mahajanga, Boeny (www.inaturalist.org/observations/20766277) 1 anterior view 2 dorsal view.
Madagopsina tschirnhausi
Holotype, ♂ (
Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov. can be recognised by its medium size (body length ♂ 7.3 mm), brown colour (however, due to conservation in alcohol it is likely that all the brown colours would be more yellowish in a live specimen, like in the other Madagopsina species), body mainly thinly pruinose (pollinose) with few small setulae, only katepisternum and katepimeron glossy, absence of facial teeth, medium-sized inner vertical seta (1.7 × stalk diameter), scutellar spines 2.0 × as long as scutellum, quite large apical seta (45% of scutellar spine length), incrassate fore femora with around 48 tubercles, irrorated wings with three vague crossbands including an H-shaped configuration with central and preapical crossbands, wing apex infuscated, central band slightly broader than preapical band, pale wing spots in cell r2+3 and cell m1, a vague pale spot in cell m4, abdomen club-shaped, no pruinose spots on tergites, ♂ spiracles 7 in slit of synsternite 7+8, surstyli rounded and bulbous with an apically rounded apophysis, microtrichia on posterior apical third, phallapodeme with ratio posterior arm/anterior arm 1.05, straight ejaculatory apodeme with only a slight sickle-shape apically, phallus remarkably broad and sclerotised, assumed moderate sexual dimorphism with regards to eye span (D ≈ 1.0), ratio eye span/body length ~ 1.20 in ♂. Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov. belongs to the M. apollo species group, which furthermore includes M. apollo and M. parvapollina.
Measurements . Body length ♂ 7.3 mm; eye span 8.8 mm; wing length 5.9 mm; length of scutellar spine 1.01 mm.
Head. Central part brown, ocellar tubercle and arcuate groove dark brown; central head thinly pruinose (Figs
Thorax. Collar, scutum, scutellum and postscutellum pruinose, brown (Figs
Wing. Irrorated with a rather vague, brownish, H-shaped configuration; apex (8% of wing length) with brownish infuscation (convex on proximal side); 3 crossbands, the basal and central band hardly separated, a pale preapical band and three pale spots (Figs
Legs. Coxa 1 pale yellowish, glossy but with dense white pruinescence on anterior side, trochanter 1 pale, pruinose; fore femur yellowish brown but dorsally darker, glossy but dorsally and apically pruinose; fore tibia and metatarsus darker brown, other fore tarsi pale and covered with whitish pruinescence; mid- and hind legs more uniformly yellowish, femora pruinose dorsally and with dark brown spot on apical fifth; femur 1 (Figs
Preabdomen. Abdomen club-shaped (ratio length/broadest width 2.8); syntergite gradually widening posteriorly, seam between tergites 1 and 2 not visible, suture between tergites 2 and 3 distinct (Fig.
Postabdomen male. Sternite 4 a rectangular plate; sternite 5 (Fig.
Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov., ♂, holotype, Makay 18 epandrium with surstyli and cerci, posterior view 19 surstylus, inner view 20 hypandrial clasper, lateral view 21 phallapodeme and phallus, lateral view 22 ejaculatory apodeme and sac. Scale bars: 0.5 mm (18, 21); 0.1 mm (19, 20, 22).
The new species is only known from the Makay massif in Toliara province. The Makay is a mountain range of almost 4000 km2 in southwestern Madagascar. The altitude varies from 200 m at the bottom of canyons to 1000 m for the plateaus. The Makay with its exceptional biodiversity (see
This species is named M. makayensis Feijen, Feijen & Feijen, sp. nov., referring to the place of origin of the holotype.
This key is a revised version of the Madagopsina section of the key in
Posterior view of Madagopsina surstyli 23–25 M. apollo species group 26–28 M. apographica species group 23 M. apollo 24 M. makayensis Feijen, Feijen & Feijen, sp. nov. 25 M. parvapollina 26 M. apographica 27 M. freidbergi 28 M. tschirnhausi. Scale bar 0.1 mm (all drawn to the same scale). Figures 25–28 (
1 | Fore femur incrassate in females (ratio length/width 3.4–3.5) and males (ratio length/width 3.2–3.7) (Figs |
2 (Madagopsina apollo species group) |
– | Fore femur moderately incrassate to slender in females (ratio length/width 4.6–6.0) and males (ratio length/width 4.6–6.3), pleurotergal spines posterolaterally directed, dark preapical wing band (width 13–14% of wing length) distinctly narrower than central band and darker (Figs |
4 (Madagopsina apographica species group) |
2 | Large – females on average 9.6 mm (range 8.3–10.2), males on average 9.5 mm (range 8.0–10.1), inner vertical seta 0.8 × stalk diameter, small apical seta (23% of length of scutellar spine), male sternite 5 without combs, apophysis of surstylus short (~ 30% of length of surstylus) and bulbous (Fig. |
Madagopsina apollo |
– | Medium-sized – females on average 6.1 mm (range 5.4–6.8), males on average 6.3 mm (range 5.6–7.0) or just larger to 7.3 mm (M. makayensis Feijen, Feijen & Feijen, sp. nov.), inner vertical seta 1.6–1.7 × stalk diameter (Figs |
3 |
3 | Body length of male 7.3 mm, apical seta 45% of length of scutellar spine, anterior central hyaline wing spot in cell r2+3 and not extending into cell r1 (Fig. |
Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov. |
– | Body length males on average 6.3 mm (range 5.6–7.0), apical seta on average 37% of length of scutellar spine, anterior central hyaline wing spot in cells r1 and r2+3 (Fig. |
Madagopsina parvapollina |
4 | Inner vertical seta 2.3 × stalk diameter, femur 1 moderately incrassate in females and males (ratio length/width in both sexes 4.6), ratio scutellar spine/scutellum 2.1–2.3, dark preapical wing band rather vague but slightly darker than central band (Fig. |
Madagopsina tschirnhausi |
– | Inner vertical seta 1.1–1.4 × stalk diameter, femur 1 slender in females (ratio length/width 5.3–5.9) and males (ratio length/width 5.3–6.3), ratio scutellar spine/scutellum 2.5–3.1, dark preapical wing band distinct and much darker than central band (Figs |
5 |
5 | Inner vertical seta 1.4 × stalk diameter, femur 1 slender in females and males (ratio length/width 5.3), ratio scutellar spine/scutellum 2.9–3.1, preapical dark band uniformly dark, only paler in cell r1 (Fig. |
Madagopsina apographica |
– | Inner vertical seta 1.1× diameter of stalk, femur 1 very slender in females (ratio length/width 6.0) and males (ratio length/width 6.3), ratio scutellar spine/scutellum 2.5, preapical dark band with distinctly darker spot around vein R4+5 (Fig. |
Madagopsina freidbergi |
For all five Madagopsina species included in
Eye span plotted against body length for the three species in the Madagopsina apollo species group: M. apollo, M. parvapollina and M. makayensis Feijen, Feijen & Feijen, sp. nov. Note the position of the single data point for the ♂ of the latter species, in line with the ♂ data points for M. parvapollina.
According to
Due to the description of a new species in the M. apollo species group, the list of differences with the M. apographica group has to be somewhat revised. A major difference between the two groups, according to
Differential character states for the Madagopsina apollo species group and Madagopsina apographica species group.
Character | Madagopsina | ||
---|---|---|---|
apollo species group | apographica species group | ||
head | arista | basal half finely microtrichose | almost bare |
thorax | scutum length/width | 0.80–0.88 | 0.93–0.95 |
pleurotergal spines | laterally directed | posterolaterally directed | |
wing | width dark preapical band/wing length | 0.18–0.20 | 0.13–0.14 |
dark preapical band | as broad as central band and equal in colour | distinctly narrower than central band and darker | |
femur 1 | ratio length/width ♀ | 3.4–3.5 | 4.6–6.0 |
ratio length/width ♂ | 3.2–3.7 | 4.6–6.3 | |
abdomen | shape | club-shaped | slender |
ratio length/broadest width | ≤3 | ~4 | |
tergite 3 | no spots | one pair of lateral spots | |
sternite 2 length/width | 1.2–1.6 | 1.9–2.8 | |
length St1+St2+St3/ width posterior St2 |
2.8–3.1 | 4.1–4.8 | |
genitalia | ratio posterior/anterior arm of phallapodeme | 1.1–1.4 | 0.7–0.9 |
The division of Madagopsina into the M. apollo species group and the M. apographica species group is consolidated by the inclusion of the morphological data for M. makayensis Feijen, Feijen & Feijen, sp. nov. Within the M. apollo group, the new species is more closely related to M. parvapollina. The division into two species groups and the closer relationship of M. makayensis Feijen, Feijen & Feijen, sp. nov. to M. parvapollina is fully supported by the geometric morphometrics analysis of wing shape and the analysis of the allometric data with regard to eye span.
The many live Diopsidae photographs made available via www.iNaturalist.org are greatly appreciated. Via this website, photographs and/or records supplied by “lemurtaquin”, Éric Mathieu, Gernot Kunz, Josiane Lips, and Olivier Testa could be examined. The permission to use two photographs by Gernot Kunz is gratefully acknowledged. We are grateful to the editor-in-chief of Tijdschrift voor Entomologie, Herman de Jong, for permission to reuse figures earlier published in that journal. The comments by Steve Gaimari and an anonymous reviewer were greatly appreciated.