Pherbellia shatalkini Rozkošný, 1991

Vikhrev, Nikita E. & Murphy, William L., 2022, Notes on the taxonomy of species of Sciomyzini with a predominantly setulose anepisternum (Diptera, Sciomyzidae), Amurian Zoological Journal XIV (2), pp. 281-298 : 285-287

Pherbellia shatalkini Rozkošný, 1991

Figs. 3 , 4, 6

Type material: Holotype, ♂: RUSSIA: Amur Reg., Zeya env., (53.7 ° N, 127.3 ° E), A. Shatalkin, 13.09.1981 . Paratypes: the same locality and collector as the holotype : 21.06.1978, 1♂; 10.07.1978, 1♂ (all ZMUM) .

Other specimens examined:

MONGOLIA, Arkhangai aimak (48 ° N, 101 ° E) , 28.08.1967, V. Zaitsev, 1♂ ( ZIN) .

RUSSIA: Khabarobsk Reg.: Khabarovsk, 48.6 ° N, 135.1 ° E, 2– 6.06.2014, N. Vikhrev, 1♂; Sindinskoe L., 48.92 ° N, 136.24 ° E, 7.06.2014, N. Vikhrev, 1♂; Komsomolsk-on-Amur, Mylki L., 50.5°N, 136.98°E, 21.06.2022, N. Vikhrev, 1♂ (all ZMUM) ;

Khakassia Reg., Beltirskoe env., 53.038 ° N, 90.462 ° E, 10.05.2018, N. Vikhrev, 2♂ ( ZMUM) ;

Tuva Reg.: Kyzyl env., 51.7 ° N, 94.7 ° E, 17– 25.05.2018, N. Vikhrev, 3♂, 2♀; Uyuk R ., 800 m, 52.07 ° N, 94.04 ° E, 27.05.2018, N. Vikhrev, 1♀ (all ZMUM) .

USA, Alaska, Matanuska (61.4 ° N, 150.2 ° W), 8.10.1944, J. C. Chamberlin, 1♂, 1♀ (♀ with G. C. Steyskal’s identification label Ph. griseola ; both ♂ and ♀ with presumably K. Elberg’s handwritten label “not griseola — hind 1/2 mspl. haired”) (all ZIN) .

Remarks. Specimens from Alaska show that Ph. shatalkini is actually a Holarctic species, while the record of Ph. griseola ( Steyskal 1954: 55) is misidentification. Steyskal (1954: fig. 1 and here Fig. 6 ) wrote, “A figure of the male terminalia of one of the Matanuska specimens is presented to facilitate eventual check against Palaearctic material.” This case illustrates how difficult it is to use the male genitalia for identification. Steyskal’s drawing of the posterior surstylus shows it to be similar to those of both Ph.

shatalkini and Ph. griseola . His drawing of the anterior surstylus shows it to be more similar to that of Ph. shatalkini than to the “dog head profile like” shape of that of Ph. griseola . Illustrations of the genitalia of Ph. shatalkini from the original description by Rozkošný (1991: figs. 13–14) are shown in Fig. 4 . Kurina et Knutson (2019) recently redescribed the male genitalia of Ph. shatalkini , noting that the anterior surstylus bears 7–8 rather strong spinules ( Fig. 3 ). The anterior surstylus of Ph. griseola also has been depicted as spinulose ( Rozkošný 1991: fig. 37 and our Fig. 5 ; Vala 1989: fig. 33c; Rivosecchi 1992: fig. 46b and tab. IXe). In fact, the anterior surstylus of Ph. griseola does not bear spinules but bears rather very fine and barely visible hairs on the inner side. To summarise, Steyskal (1954) drew the terminalia of Ph. shatalkini , while the presence of Ph. griseola in the Nearctic requires confirmation. These species may be identified as follows:

— Anepisternum with weak setulae on most of it surface. Arista bare. Postpedicel mostly black. Crossveins only slightly darkened. ♂: anterior surstylus with strong spinules.......................... Ph. shatalkini

— Anepisternum with setulae along posterior margin only, stronger than those on anepisternum of Ph. shatalkini . Aristal hairs almost as long as half width of postpedicel. Postpedicel yellow. Crossveins distinctly darkened. ♂: anterior surstylus with fine hardly visible hairs on inner surface................................... Ph. griseola

Distribution. Holarctic species. In eastern Palaearctic known from 90 ° E to Far East (136 ° E), also S Korea ( Son, Suh 2019); north to 53 ° N, south to 48 ° N. Alaskan specimens have been collected much farther north (61.4 ° N). Other Nearctic records require reexamination as follows from Remarks, above.

Rozkošný (1987: 18) described the genus Ditaeniella as follows: “Frons mainly matt, mid-frontal stripe elongated and tapered anteriorly, only one orbital seta present. Propleural seta distinct, prosternum haired, also mesopleuron covered with distinct hairs. Inner posterior margin of hind coxa with several hairs. Anal vein on wing reaching posterior wing margin. Male sternum 7 haired, gonostyli partly reduced and postgonites with conspicuous spines.” He noted, “This combination of characters, the majority of which (especially 1 orbital seta, spines on postgonites, partly reduced gonostyli) belongs obviously to apotypic ones, is not known in any [other] group of the Sciomyzini .” As we mentioned in the Introduction, distinguishing between Ditaeniella and other taxa of Sciomyzini with a predominantly setulose anepisternum is not as straightforward as it is with most other taxa of Sciomyzini .

We compare the diagnostic morphological characters of these five taxa in Table 1.

Table 1 Comparison of morphological characters of Ditaeniella with those of other taxa of Sciomyzini with a predominantly setulose anepisternum* ТабΛица 1 Сравнение морфоΛогических признаков Ditaeniella с таковыми у Áругих таксонов Sciomyzini с анэпистернумом, преимущественно покрытым воΛосками*

1. The midfrontal stripe of Ditaeniella differs slightly in different specimens. It usually appears as a long sharp-angled triangle ( Fig. 16 ). It is not as long and parallel sided as in Ph. cinerella but it is noticeably different from the short, pointed triangle found in more typical Pherbellia taxa.

2. Ditaeniella species have one pair (posterior) of fronto-orbital seta. Similarly, only one pair of fronto-orbital setae is present in Pteromicra glabricula , in both species of Salticella , and in several taxa of Tetanocerini . In Atrichomelina , a weak anterior pair of fronto-orbital setae are sometimes present.

3. Among Sciomyzini with a predominantly setulose anepisternum, a setose prosternum is unique in Ditaeniella sensu Rozkošný (bare in D. trivittata ). A setose prosternum also is found in Sciomyza species and several taxa of Tetanocerini .

4. The anepisternal setulae are slightly less extensive in Ph. shatalkini and much less extensive in D. trivittata than in D. grisescens . In the Ph. dorsata group, the anepisternum is setulose along the posterior margin only. In the Tetanocerini , the presence of setulae or setae on the anepisternum is a genus-specific character.

5. In the Nearctic Ph. seticoxa , the hind coxa bears a few fine hairs on the inner posterior margin ( Murphy et al. 2018: 65, 80). In the Tetanocerini , the presence of hairs on the inner posterior margin of the hind coxa is a genus-specific character.

6. Species of Ditaeniella have very similar genitalia that differ only in fine details ( Figs. 7–9 , 13, 15 ). Likewise, the general genitalic structure of Ph. pilosa and Ph. shatalkini is similar to that of each other ( Figs. 1, 3 ). In contrast to these similarities, the genitalic ground plans of Ditaeniella , Atrichomelina , and taxa of Pherbellia with a setulose anepisternum differ conspicuously from each other. Thus, the genitalic ground plan may be used as generic character, although applicable to male specimens only.

7. Microsetulae are present on the meron of species of Ditaeniella and Atrichomelina ( Fig. 10 ). The diagnostic value of these microsetulae is limited because they are not distinct in all specimens and have been overlooked in previous published descriptions of species. The same microsetulae usually are present on meron of Ph. cinerella , and stronger setulae are present on the meron of species in the Ph. dorsata group.

8. As with Atrichomelina , some specimens of Ph. shatalkini lack strong seta(e) on the anepimeron.

9. Males of Ditaeniella have two rows of strong, short setae on the ventral side of the hind femur, one anteroventral and one posteroventral, with no setae between the rows, only setulae ( Figs. 11 , 12 , 17 ). The rows extend almost the full length of the femur and are denser on the apical half than on the basal half. Neither Atrichomelina nor species of Pherbellia with a predominantly setulose anepisternum have such rows of spinulose av and pv setae, although ventral setulae (longer or shorter, dense or sparse) may be present. Females of Ditaeniella usually have at least 1–2 av seta(e) near the apex of the hind femur, except for D. milleri sp. nov., which has 4–5 av and 2–4 pv setae.

Conclusions. 1) Both sexes of the five species considered in Table 1 may be distinguished reliably from each other on the basis of external morphology, without examination of the genitalia. 2) A generic diagnosis of a group consisting of Ditaeniella , Atrichomelina , and species of Pherbellia with a predominantly setulose anepimeron is difficult to formulate; thus, we think it is most reasonable to retain the currently accepted division by genera until further results of molecular phylogenetic analyses become available.

Figures

Figs. 1–3. 1 — Ph. pilosa, ventral view, postabdomen showing anterior surstyli (at bottom), each with about 15 spinules; 2 — Ph. pilosa, male terminalia, lateral view, anterior surstylus with spinules (from Rozkošný 1991: fig. 49); 3 — Ph. shatalkini, ventral view, postabdomen showing anterior surstyli (at bottom), each with 7–8 spinules stronger than those of Ph. pilosa (from Kurina, Knutson 2019) Рис. 1–3. 1 — Ph. pilosa, постабΔомен снизу, виΔны переΔние сурстиΛи, кажΔый с примерно 15 шипиками; 2 — Ph. pilosa, терминаΛии самца, виΔ сбоку, переΔние сурстиΛи с шипиками (по Rozkošný 1991: fig. 49); 3 — Ph. shatalkini, постабΔомен снизу, виΔны переΔние сурстиΛи, кажΔый с примерно 7–8 шипиками, которые сиΛьнее, чем таковые у Ph. pilosa (по Kurina, Knutson 2019)

Figs. 4–6. 4 — Ph. shatalkini, male postabdomen, ventral view, male terminalia, lateral view (from Rozkošný 1991: figs. 13–14); 5 — Ph. griseola, male terminalia, lateral view (from Rozkošný 1991: fig. 37); 6 — Ph. shatalkini (as Ph. griseola), male postabdomen, lateral and ventral views (from Steyskal 1954: fig. 1) Рис. 4–6. 4 — Ph. shatalkini, постабΔомен самца, виΔ снизу и сбоку (по Rozkošný 1991: figs. 13– 14); 5 — Ph. griseola, терминаΛии самца сбоку (по Rozkošný 1991: fig. 37); 6 — Ph. shatalkini (as Ph. griseola), постабΔомен самца, виΔ сбоку и снизу (по Steyskal 1954: fig. 1)

Figs. 16–19. Ditaeniella parallela, male: 16 — dorsal view; 17 — ventral view with arrow indicating ventral spines on f3; 18 — postabdomen, ventral view, postgonites are visible, each bearing only a single spine; 19 — postabdomen, lateral view with arrow pointing to apically curved sclerotised portion of cerci Рис. 16–19. Ditaeniella parallela, самец: 16 — виΔ сверху; 17 — виΔ снизу, стреΛка указывает на вентраΛьные шипики на f3; 18 — постабΔомен снизу, виΔны постгониты, кажΔый из которых несет по оΔному шипику; 19 — постабΔомен сбоку, стреΛка указывает на скΛеротизированные выросты на церках

Figs. 7–9. Postabdomen ofDitaeniella species in lateral view (modified from Steyskal 1963: figs. 8–10): 7 — D. grisescens; 8 — D. patagonensis; 9 — D. parallela Рис. 7–9. ПостабΔомен таксонов Ditaeniella, виΔ сбоку (по Steyskal 1963: figs. 8–10): 7 — D. grisescens; 8 — D. patagonensis; 9 — D. parallela

Figs. 12–15. Ditaeniella milleri sp. nov., male (12, 13): 12 — ventral spines at apex of anterior femora; 13 — postgonites; Ditaeniella grisescens, male (14, 15): 14 — ventral setae at apex of anterior femora; 15 — postgonites Рис. 12–15. Ditaeniella millerisp. nov., самец (12, 13): 12 — вентраΛьные шипы на переΔнем беΔре; 13 — постгониты; Ditaeniella grisescens, самец (14, 15): 14 — вентраΛьные шипы на переΔнем беΔре; 15 — постгониты

Figs. 10–11. Ditaeniella milleri sp. nov.: 10 — microsetulae on meron; 11 — male holotype Рис. 10–11. Ditaeniella milleri sp. nov.: 10 — воΛоски на мероне; 11 — гоΛотип, самец