Limnia pacifica Elberg, 1965

Vikhrev, Nikita E., 2023, Notes on the Palaearctic fauna of Limnia (Diptera, Sciomyzidae), Amurian Zoological Journal XV (2), pp. 284-292 : 289-291

Limnia pacifica Elberg, 1965

Figs. 5‒8 , 14

Limnia japonica Yano, 1978 syn. nov.

RUSSIA, Sakhalin Reg.: Kunashir Isl.: Alekhino (≈ 43.917 ° N, 145.528 ° E), 2.06.1968, E. Narchuk, 1♀ ; Mendeleevo (43.957 ° N, 145.689 ° E), 29‒ 30.07.1971, E. Narchuk, 1♂, 1♀ ; Sernovodsk : (≈ 43.906 ° N, 145.642 ° E), 30.06.1971, E. Narchuk, 1♀ ; I. Kerzhener , 26.08.1973, 1♀ ; Tretyakovo (≈ 43.988 ° N, 145.644 ° E): 4‒ 5.07.1968, E. Narchuk, 1♂, 2♀ ; 9.07.1971, E. Narchuk, 1♂; V. Tanasiychuk , 6.09.1971, 1♀ (all ZIN) ; Mendeleev volcano env. (≈ 43.98 ° N, 145.73 ° E), 20.07.1985, S. Churkin, 1♀ ; Stolbchaty cape (≈ 44.02 ° N, 145.69 ° E), 13.07.1985, S. Churkin, 1♀ ; Andreevsky Cordon , 43.54 ° N, 145.37 ° E, 6‒ 8.07.2014, A. Gomyranov, 1♂, 1♀ ; Saratovsky Cordon , 44.15 ° N, 146.06 ° E, 19‒ 23.07.2014, A. Gomyranov, 1♀ ; Yuzhno- Kurilsk , 43.59 ° N, 145.38 ° E, 15‒ 18.07.2014, A. Gomyranov, 1♀ ; Shikotan Isl., Tserkovnaya Bay , 43.75 ° N, 146.70 ° E, 11‒ 17.06.2012, Yu. Sundukov, 1♂ ; Iturup Isl., Goryachie Kluchi , 45.0 ° N, 147.8 ° E, 17‒ 29.08.2022, V. Savitsky, 1♂ .

DISTRIBUTION. Restricted to Pacific Islands: the Kuril Islands (Kunashir, Shikotan and Iturup) and Japan (known from Honshu and Kyushu).

REMARKS. Two females from Kunashir have strong (as in Psacadina ) seta on anepisternum.

SYNONYMY. Alas, it is sometimes assumed that for describing a new species, it is enough to indicate a character not mentioned in the original description of a similar species, though this character well may be a result of intraspecific variability. In the worst case, not a single character is even indicated, as in the case of L. japonica . On the other hand, many colleagues are convinced that serious justifications are required for the suggestion of synonymy. With this approach, it becomes increasingly difficult to distinguish species, but biodiversity gets “enriched” every year. Meanwhile, in accordance with the basic method of scientific knowledge (Occam's principle), any doubts should be interpreted in favor of synonymy, so as not to produce unnecessary entities. Synonymy is not a verdict but only a statement of the fact that there is no reason to consider some species as different, for example, the populations of unguicornis -like Limnia in the Kuril and Japanese Islands. No comprehensible difference follows either from the original description or from other publications, while a short publication with an indication of reliable diagnostic characters would be enough for the resurrection of the synonymized species.

L. japonica was described from specimens collected from Honshu and Kyushu Islands of Japan. Yano (1978: 5–10) compared his other species ( L. setosa ) with hardly similar L. pacifica , but Yano compared L. japonica only with the W Palaearctic L. unguicornis but not with L. pacifica distributed in the Pacific Islands. According to Yano, L. japonica and L. unguicornis differ only in the male genitalia structure. Actually, as follows from the discussion under L. unguicornis and Figs. 5–8 , L. japonica has the same genitalia as L. pacifica . Rozkosny (1987: 66–67) tried to save the validity of L. japonica proposing brownish longitudal stripe in the middle of the face as a diagnostic character. However, Sueyoshi (2001: 497–498) found out, after examination of a large series, that there is a gradual intraspecific variability: the facial stripe is distinct in S Japan and indistinct in N Japan (we could add: usually absent in the Kuril Islands). So, L. pacifica Elberg, 1965 = L. japonica Yano, 1978 syn. nov.

Limnia kassebeeri Mohamadzade Namin, 2017 REMARKS. The species was described from a series of specimens from NW regions of Iran (Kurdistan, E Azerbaijan and Gilan provinces). According to the diagnosis, “… in some specimens of L. kassebeeri , anepisternum contains one small seta in addition to fine hairs. Hypandrium in L. kassebeeri sp. n. has two ventral processes, whereas in L. unguicornis and L. paludicola the number of ventral processes of hypandrium is three ...“. In the photo of the holotype of L. kassebeeri ( Sadr, Namin 2017: fig. 2A) we can see: (a) scutum with grey submedian vittae; (b) postpedicel about as long as pedicel; (c) costal margin of wing with distinct round dark spots; (d) rather strong seta on anepisternum.

Characters a and b are typical for L. unguicornis .

Character c is typical for L. pacifica . Some specimens of L. unguicornis have indistinct costal spots, only one female from S Dagestan (again Caspian region) has very distinct dark costal spots.

Character d was never found in L. unguicornis . Two our specimens of L. pacifica have remarkably strong anepisternal seta, several more specimens have shorter but still elongated setulae on anepisternum.

We have a female specimen from Lichk ( Armenia), collected 30 km north of some specimens from E Azerbaijan province listed as L. kassebeeri by Sadr & Namin (2017). This female is typical L. unguicornis .

I tend to regard the above data as manifesting a curious variability of Limnia . However, if to correct wording by Sadr & Namin (2017) from “some specimens” to “those specimens which have seta on anepisternum and bilobed hypandrium in male”, then L. kassebeeri would at least have a comprehendible diagnosis with two independent diagnostic characters. Thus, my decision is to postpone L. kassebeeri for now for the future reexamination of the type material and examination specimens to be collected in the Caspian region.

Figures

Figs. 2–8. Hypandrium of Limnia: 2–4, L. unguicornis: 2 — our photo; 3 — L. paludicola; 4 — L. unguicornis (3, 4 from Elberg 1965: figs. 16, 17); 5–8 — L. pacifica: 5 — our photo; 6 — (from Elberg 1965: fig. 18); 7 — (from Przhiboro 2016: fig. 13); 8 — (from Yano 1978: fig. 9)