Lispe caesia, Meigen, 1826

Vikhrev, Nikita E., 2020, Lispe (Diptera, Muscidae) of the Palaearctic region, Amurian Zoological Journal XII (2), pp. 158-188 : 180-181

III. Lispe caesia group

I only partly considered the Lispe caesia group in previous papers. The L. caesia group was proposed by Hennig (1960) for 6 Palaearctic taxa: L. caesia caesia Meigen, 1826 ; L. caesia microchaeta Seguy, 1940 ; L. candicans Kowarz, 1892 ; L. halophora Becker, 1903 ; L. leucocephala Loew, 1856 and L. odessae Becker, 1904 . Hennig (1960) wrote that the L. caesia group is one of the most clearly bordered and pointed out its following diagnostic characters: (1) frontal triangle broad, with convex margins; (2) femora with ventral rows of short spines; (3) abdomen with characteristic pattern. However, there is an evident discrepancy in Hennig’s approach to the L. caesia group: he included in the group L. leucocephala , which has neither spines on femora, nor the typical abdominal pattern, while he did not include in the group L. marina , which has all the diagnostic characters except broad frontal triangle. In the recent review of the L. caesia group, Zhang et al. (2016) included in the group several other species with narrow frontal triangle (again except for the unlucky L. marina ), but did not give any substantiation of this. Zhang et al. (2016) included in the L. caesia group the following Palaearctic taxa: 5 out of 6 Hennig’s taxa (except for L. odessae previously synonymized to L. caesia ) and 6 new taxa: L. aquamarina Shinonaga & Kano, 1983 ; L. flavicornis Stein, 1909 ; L. hirsutipes Mou, 1992 ; L. lanceoseta Wang & Fan, 1981 ; L. palawanensis Shinonaga & Kano, 1989 ; L. patellitarsis Becker, 1914 . Later, Chinese colleagues and I ( Vikhrev et al. 2016) refuted the groundless synonymy of L. odessae , but synonymized L. c. microchaeta to L. c. caesia . In the present paper L. palawanensis known from Philippines is excluded as a non-Palaearctic species and L. hirsutipes is excluded as synonym. Three species, L. bengalensis Robineau-Desvoidy, 1830 ; L. marina Becker, 1913 and L. astakhovi sp. nov. are included here in the L. caesia group for the first time. Thus, in the present paper 11 Palaearctic species of the L. caesia group are considered in total.

I suppose that characters offered by Hennig for the L. caesia group are really apomorphic, because they do not occur among other species of Lispe . I add one more character: hind coxa with seta on inner posterior margin. (It should be mentioned that the seta on the hind coxa occurs also in three species of Lispe belonging to the L. palposa group.) This seta on the hind coxa is absent in several species distributed in Australia and Sundaland and in Paleotropical L. bengalensis . Pont (2019) proposed to include several Australian species with bare hind coxa in a separate L. cana group, but I am inclined to regard these Lispe as belonging to the L. caesia group. According to so far unpublished molecular data on phylogeny of Lispe obtained by Zhang Dong, his co-workers and me, at least L. bengalensis is closely related to other Palaearctic species of the L. caesia group.

So, the L. caesia group has the following set of characters:

1. Femora with ventral rows of short spines (more distinct in females, less so in males) ( Fig. 48 ).

2. Abdomen with characteristic pattern: black dorsal spots on posterior part of tergite 4 fused with antero-lateral spots on tergite 5 (see Fig. 47 or Zhang et al. 2016: Figs 8 a and e ).

3. Frontal triangle broad, with convex margins; often the frons is evenly and densely silvery-white ( Fig. 5 ) or yellow dusted so frontal triangle is hardly distinct.

4. Hind coxa with seta on inner posterior margin (absent in L. bengalensis and L. lanceoseta ).

5. As to the current knowledge, all species are active predators on imago of other Diptera ( Figs 10 and 17 ). This habit is not common in Lispe , the only other example of obligatory predation on Diptera imago is L. geniseta Stein, 1909 (Vikhrev 2016). Typically, Lispe hunt on soft insect larvae (like Chironomidae larvae) or (and) feed on invertebrate carrion. The active hunting is closely associated with the presence of ventral spines on femora; the stronger development of spines in female sex shows that its function is not mating but hunting.

6. All species are confined to salt water (from brackish to hypersaline), they inhabit either seashores or inland salt basins.

7. Male genitalia with rather uniform, heart-shaped cercal plate but the shape of surstyli is often characteristic. The inner side of sternite 5 has a pair of internal sclerites, the shape of which is usually characteristic for species.

8. Male tar3-1 is often modified ( Figs 17 , 22 , 49, 50 ).

9. Meron is bare in all Palaearctic species (setulose in several species from Australia (see: Pont 2019) and Sundaland).

10. The L. caesia group is distributed in warm regions of the Old World. The northernmost species is L. caesia which extend till 56°N along the Atlantic coast; in W Siberia L. caesia and L. odessae are recorded at 51.3°N. No wonder that Bering Land Bridge was too cold for the species of the L. caesia group to spread to America.

Only the minority of species of the L. caesia group kept all these characters, while the majority lost some of them.

Figures

Figs 47–50. 47 —L. halophora, male;48 —L. bengalensis, ventral spines onf1; 49 —L. caesia, male tar3-1; 50 —L. odessae, male tar3-1 (49–50, from Hennig 1960, 404: textfigg 100 and 98) Рис. 47–50. 47 — L. halophora, самец; 48 — L. bengalensis, вентраΛьные шипики на f1; 49 — L. caesia, tar3-1 самца; 50 — L. odessae, tar3-1 самца (49–50, по Hennig 1960, 404: textfigg 100 and 98)

Figs 4–9. L. astakhovi sp. nov. (4–7): 4 — the holotype, general view, lateral; 5 — the holotype, head, anterior view; 6 — cercal plate;7 — sternite 5; L. marina, male (8–9): 8 — head, anterior view; 9 — mid tarsus, anterior view (from Bergerard 1995) Рис. 4–9. L. astakhovi sp. nov. (4–7): 4 — гоΛотип, общий виΑ сбоку; 5 — гоΛотип, спереΑи; 6 — церки; 7 — стернит 5; L. marina, самец (8–9): 8 — гоΛова, спереΑи; 9 — среΑняя Λапка, спереΑи (по Bergerard 1995)

Figs 10–15. L. candicans: 10 — male with another male as prey (Senegal);11 —f emale (Spain, photo Piluca Alvarez); 12 — sternites 5–6, West African male; 13 — sternites 5–6, Indian male; 14 — surstylus, West African male; 15 — surstylus, Indian male Рис. 10–15. L. candicans: 10 — самец, поеΑающий Αругого самца (СенегаΛ); 11 — самка (Испания, фото Piluca Alvarez); 12 — стерниты 5–6, самец из ЗапаΑной Африки; 13 — стерниты 5–6, самец из ИнΑии; 14 — сурстиΛь, самец из ЗапаΑной Африки; 15 — сурстиΛь, самец из ИнΑии

Figs 16–17. 16 — L. marina, male (photo: Rui Andrade); 17 — L. flavicornis, male with prey (Dolichopodidae, (Amblypsilopus?))

Figs 18–22. L. bengalensis, male (18–20): 18 — dorsal view; 19 — lateral view; 20 — head; L. lanceoseta, male (21–22) (from Zhang et al. 2016): 21 — mid leg; 22 — hind leg Рис. 18–22. L. bengalensis, самец (18–20): 18 — виΑ сверху; 19 — виΑ сбоку; 20 — гоΛова; L. lanceoseta, самец (21–22) (из Zhang et al. 2016): 21 — среΑняя нога; 22 — заΑняя нога