Milesia cretica Bot & van Steenis, 2022

Bot, Sander, Mengual, Ximo, Steenis, Jeroen van & Skevington, Jeffrey H., 2022, A new species of the genus Milesia Latreille (Diptera: Syrphidae) from Crete, European Journal of Taxonomy 846, pp. 110-125 : 112-120

Milesia cretica Bot & van Steenis sp. nov.

urn:lsid:zoobank.org:act:8DBF585C-4511-4600-A7E1-4BC10B851E60

Figs 1–3 , 7–8

Differential diagnosis

Milesia cretica sp. nov. ( Figs 2–3 ) belongs to the Milesia crabroniformis species group (see Remarks below), of which M. crabroniformis hitherto was the only member ( Hippa 1990). It differs from M. crabroniformis ( Fig. 4 ) as follows: vertex blackish caused by less dense pollinosity, completely yellow in M. crabroniformis ; female frons medially with indistinct brown longitudinal vitta caused by the absence of pollinosity, completely yellow in M. crabroniformis ; ground colour of the scutum is black except for a small rectangular orange brown part between the postalar calli, in M. crabroniformis the orange brown ground colour is much more extensive forming longitudinal vitta on the posterior part of the scutum; scutum with heavy yellow pollinose pattern on both anterior and posterior part of scutum, in M. crabroniformis the yellow pollinosity is less extensive on the posterior part, making the orange brown ground colour pattern visible, creating a colour contrast between the yellow pollinose pattern on the anterior part and an orange brown ground colour pattern on the posterior part; on the medial part of the scutum two short yellow pollinose vittae depart as part of the anterior vittae into the posterior part, in M. crabroniformis these yellow pollinose vittae are absent; the anterior half of the scutellum is black, in M. crabroniformis the scutellum is usually all red or only with a small anterior portion black, anterior half seldom black; scutellum completely yellow pilose, at least one or a few black pili present in M. crabroniformis ; in the male, pleura, coxae and trochanters largely black, on average with more yellow markings in M. crabroniformis . Legs are more extensively black marked but less extensively black pilose in Milesia cretica sp. nov.; metatibia medially with black markings and ventrally covered with black pile for some 25% of the length of the tibia in the male, in M. crabroniformis no black markings are present on metatibia, but black pile is more extensive, covering at least 40% of the length of the tibia; in the female, the metatibia is covered with black pile for some 10% of the length of the tibia, at least 30% in M. crabroniformis . Milesia cretica sp. nov. has the anterior half of the wing not clearly yellowish tinged and without subtle darker greyish subapical macula, the former character (clearly yellowish tinged) always present and the latter (subtle darker greyish subapical macula) usually present in M. crabroniformis . Terga 2–4 yellow and dark yellow with sharply demarcated black pattern in the new species, in M. crabroniformis colour pattern rather diffuse, extending from yellow to dark brown, without sharply demarcated black pattern. No diagnosable differences in male genitalia between the two species could be detected ( Fig. 7 ).

Etymology

The species name is from the Latin ‘ creticus, cretica ’, meaning ‘Cretan’ and it refers to the type locality of this Milesia , the island of Crete.

Type material

Holotype GREECE • ♂; Crete, Chania, Imbros Gorge ; 35°13′57.4″ N, 24°09′46.1″ E; alt. 554 m; 8 Oct. 2021; S. Bot leg.; ZFMK-DIP-00083005 .

Paratypes GREECE • 1 ♀; Crete, Chania, Ammoudari ; 16 Jun. 1971; W. Gross leg.; ZFMK-DIP-00061225 • 1 ♂; Crete, Rethymno, Monastiraki ; 35°13′44.4″ N, 24°40′33.6″ E; alt. 305 m; 6 Oct. 2021; M. van Zuijen leg.; MZW, MPZ015125 • 5 ♂♂; same collection data as for holotype; SBH, ZFMK-DIP-00083001 , ZFMK-DIP-00083002 • 1 ♂; same collection data as for holotype; AET • 4 ♂♂; same collection data as for holotype; W. van Steenis leg.; WSB, wvs11055 to wvs11058 • 1 ♂; Crete, Chania, Karanos ; 35°23′31.2″ N, 23°55′30.0″ E; alt. 580 m; 8 Oct. 2021; F. Van de Meutter leg.; FMT • 1 ♀; same collection data as for preceding; ZFMK-DIP-00082510 • 1 ♂; same collection data as for preceding; W. Opdekamp leg.; WOA • 1 ♂, 1 ♀; Crete, Chania, Askordalos ; 35°24′50.4″ N, 23°56′24.0″ E; alt. 280 m; 8 Oct. 2021; F. Van de Meutter leg.; FMT • 1 ♀; Crete, Chania, Plokamania , valley ; 35°20′50.3″ N, 23°34′53.8″ E; alt. 200 m; 8 Oct. 2021; L.J. van der Ent leg.; LEW, LJE100052 • 2 ♂♂, 3 ♀♀; same collection data as for holotype; 9 Oct. 2021; J. van Steenis leg.; JSA, 2021-001.025 to 2021-001.029 • 2 ♂♂, 1 ♀; same collection data as for holotype; 9 Oct. 2021; M. van Zuijen leg.; MZW, MPZ014979 , MPZ014977 , MPZ014990 • 1 ♀; Crete, Chania, Askordalos ; 35°24′49.3″ N, 23°56′24.0″ E; alt. 285 m; 9 Oct. 2021; S. Bot leg.; SBH • 1 ♂; Crete, Chania, near Vathi; 35°22′01.9″ N, 23°36′16.9″ E; alt. 550 m; 9 Oct. 2021; W. Opdekamp leg.; WOA • 3 ♂♂, 5 ♀♀; same collection data as for holotype; 10 Oct. 2021; F. Van de Meutter leg.; FMT • 1 ♀; same collection data as for holotype; 10 Oct. 2021; F. Van de Meutter leg.; CNC • 1 ♂, 3 ♀♀; same collection data as for holotype; 10 Oct. 2021; W. Opdekamp leg.; WOA • 2 ♂♂; same collection data as for holotype; 11 Oct. 2021; L.J. van der Ent leg.; LEW, LJE100152 , LJE100153 • 1 ♀; same collection data as for holotype; 11 Oct. 2021; L.J. van der Ent leg.; LEW, LJE100151 • 1 ♂; Crete, Rethymno, near Argyroupoli; 35°17′17.2″ N, 24°19′47.6″ E; alt. 135 m; 11 Oct. 2021; M. van Zuijen leg.; MZW, MPZ015018 • 1 ♀; same collection data as for preceding; 13 Oct. 2021; S. Bot leg.; SBH • 1 ♀; same collection data as for preceding; ZFMK-DIP-00083000 • 1 ♂; same collection data as for preceding; ZFMK-DIP-00083006 • 1 ♂; same collection data as for preceding; CNC • 1 ♂; same collection data as for preceding; USNM • 3 ♂♂, 2 ♀♀; same collection data as for preceding; F. Van de Meutter leg.; FMT • 1 ♂, 1 ♀; Crete, Rethymno, Monastiraki ; 35°13′44.4″ N, 24°40′33.6″ E; alt. 850 m; 17 Oct. 2021; J. van Steenis leg.; JSA, 2021-001.295 , 2021-001.296 • 1 ♀; same collection data as for preceding; M. van Zuijen leg.; MZW, MPZ015125 • 4 ♂♂, 1 ♀; same collection data as for holotype; 22 Oct. 2021; G. Pennards leg.; GPA .

Type locality

GREECE: Crete, Chania, Imbros Gorge; 35°13′57.4″ N, 24°09′46.1″ E; alt. 554 m.

Description

Male

LENGTH (N = 9). Body: 20–24 mm; wing: 15–17 mm.

HEAD. Face yellow; yellow pollinose; laterally yellow-pilose; in lateral profile nearly rectangular; shallowly concave; slightly tuberculate ventrally. Gena brownish black; shiny. Frons yellow; yellow pollinose; dorsally with long yellow pile. Vertical triangle with long yellow pile; yellow pollinose; black except yellow anterior of ocellar triangle. Occiput heavily yellow pollinose. Antenna yellow brown;

basoflagellomere round, as long as broad or slightly longer than broad; arista with short semi-erect pile on basal part. Eye bare.

THORAX. Scutum black; posteriorly between postalar calli with rectangular part orange brown; scutum with extensive thick yellow pollinose striped pattern ( Fig. 2 ); with erect yellow pile except fascia of black pile between wings. Postpronotum yellow; with yellow pollinosity and yellow pile. Postalar callus yellow; covered in yellow pollinosity and yellow pile with anteriorly one or a few black pili. Scutellum with anterior half black, posterior half reddish; yellow pilose; ventral scutellar fringe yellow. Posterior spiracle opened only on dorsal part. Proepisternum yellow; yellow pilose. Posterior anepisternum and dorsal part of katepisternum with large yellowish pollinose macula, remainder of katepisternum, anterior anepisternum and metasternum black. Halter yellow except base blackish. Calypter whitish with yellow posterior margin; ventral calypter with long yellow pile on posterior margin; dorsal calypter with short brown pile.

WING. Wing including alula entirely microtrichose except cell cup bare on very base and narrow vitta along anterior margin in basal half. Very base of wing and first and second costal cells slightly tinged yellow, rest of wing hyaline

LEGS. Coxae and trochanters with black and dark yellow pattern. Profemur orange; with yellow pile; with basoventral area black and weakly depressed, covered with black setulae. Mesofemur orange; ventrally with black vitta; slightly ventrally flattened; with black pile at and around ventrally flattened area, otherwise with yellow pile. Metafemur orange; with vague incomplete black ring at one third from base; ventrally with black pile, dorsally with yellow pile; ventrally at three-quarter of its length from base with well-developed spina. Pro- and mesotibia yellow; with yellow pile. Metatibia yellow; with indistinct black markings in the medial part; with yellow pile, but medio-ventrally and posterolateral with black pile, largely coinciding with black colour, covering some 25% of length of tibia. Tarsi largely dark red.

ABDOMEN. Surface of terga semi dull with shiny posterior part of tergum 4. Tergum 1 black. Terga 2, 3 and 4 largely yellow anteriorly; dark yellow posteriorly; with sharply demarcated black pattern ( Fig. 2 ). Tergum 1 with mainly black pile. Terga 2 and 3 anteriorly with yellow pile; medial black vitta and anterior part with black pile. Tergum 4 with yellow pile. Terga 7 and 8 yellow; yellow pilose. Sternum 1 black. Sterna 2 and 3 whitish-yellow; with large triangular black macula. Sternum 4 largely black; anteriorly narrowly yellow. Sterna 1–4 with long erect mainly yellow pile. Genitalia ( Fig. 7 ): Surstyli symmetrical; broad at base, horizontally elongate; with narrow pointed apicodorsal lobe and broad apicoventral lobe. Hypandrium symmetrical; ventrally mixed black and yellow pilose. Superior lobes apically with one to two spinae; position and number can differ intraspecifically between right and left superior lobes. Aedeagus symmetrical; with paired apico-dorsal lobe, ventral margin of each lobe continues as an elevated carina along the posterior margin of aedeagus.

Female

LENGTH (N = 6). Body: 17–20 mm; wing: 15–17 mm.

Similar to male except for normal sexual dimorphism and as follows: frons medially with indistinct brown longitudinal vitta caused by absence of pollinosity; femora and metatibia completely orange, without black markings; profemur with more extensive black pile; ventral black pile on metatibia covering some 10% of length of tibia.

Ecology

All collected specimens were visiting flowering Hedera helix ( Fig. 8 ). The localities of the H. helix differed, ranging from dry river beds with old Platanus trees to gardens, gorges and edges of groves. A female was flushed from a deep crevice with decaying wood at 0.5 m height in a Platanus orientalis L. Afterwards , it hovered some time with its extended ovipositor curled under de abdomen in front of this crevice before flying off. A male was seen hovering around a Castanea sativa Mill. tree as if it were defending a territory. This suggests that M. cretica sp. nov. uses P. orientalis and possibly also C. sativa as its breeding habitat.

Distribution

The species is only known from the island of Crete, Greece and is presumed to be a Cretan endemic. During the field work, Milesia cretica sp. nov. was collected from seven locations; all specimens were collected by hand with an entomological net. On the website iNaturalist under catalogue number 67354454 another observation was found: https://www.inaturalist.org/observations/67354454. All known localities are visualized in Figure 1 .

DNA barcode analysis

A total of 54 COI sequences for different species of Milesia were analysed, including our five sequences of M. cretica sp. nov. ( Fig. 9 ). The NJ tree depicts well-defined, genetically divergent clusters that reflect morphological species with high bootstrap support values (BS> 92). Our analysis recovered the Milesia crabroniformis group (BS = 99.5), our new species (BS = 100) and M. crabroniformis (BS = 100) with high support.

From the newly obtained COI sequences for M. cretica sp. nov., the sequence ON059134 (paratype ZFMK-DIP-00083002) differs 0.152% from the other four sequences, which are identical. COI barcodes of M. cretica sp. nov. differ more than 2% from the sequences of M. crabroniformis (2.13–2.66%), while the intraspecific variability in the latter taxon is less than 1% (0.0–0.68%) among the studied European specimens. In general, the intraspecific divergence among the COI sequences from the studied species is always lower than 1%, except for M. virginiensis (Drury, 1773) whose COI sequences differ 0.46– 1.52%.

Remarks

In overall appearance, M. cretica sp. nov. is remarkably similar to the Nearctic species Milesia virginiensis ( Fig. 6 ), sharing the black and yellow pattern on terga 2, 3 and 4. This is unexpected since M. virginiensis occurs in a different realm and belongs to a different species group ( Hippa 1990). The Milesia crabroniformis group differs from the Milesia virginiensis group by, for example, slightly tuberculate face; alula and cell r completely microtrichose; profemur with flattened basoventral area; and male genitalia very different ( Hippa 1990).

Milesia cretica sp. nov. belongs to the crabroniformis species group as defined by Hippa (1990). The following morphological characters are shared by M. cretica sp. nov. with the crabroniformis species group: bare anterior anepisternum; bare pleura at ventral end of posterior spiracle; face not strongly produced; proboscis normal and with short labella; cell r 1 closed; alula and posterior part of cell br completely microtrichose; posterior spiracle open only on dorsal part; male profemur with a wide basoventral depressed area; and female abdominal tergum 5 medially submembranous and laterally compressed. Still, M. cretica sp. nov. does not key satisfactorily to any of the species groups in Hippa’s (1990) key. This is because it has a partly black vertex and partly black terga compared to M. crabroniformis , and thus, not all characters univocally key out to the M. crabroniformis group in couplets 15 and 16. When disregarding the colouration, but maintaining the structural characters, M. cretica sp. nov. keys out in the M. crabroniformis species group in Hippa’s (1990) key:

15. Posterior spiracle medially widely open ( Hippa 1990: fig. 13f) .................... M. semiluctifera group

– Posterior spiracle open only on dorsal part ( Hippa 1990: fig. 30e) ................................................ 16

16. Male profemur without a large basoventral depressed area, female abdominal tergum 5 uniformly sclerotized and rigid, not laterally compressed ( Hippa 1990: 62)......................... M. undulata group

– Male profemur with a wide basoventral depressed area, female abdominal tergum 5 medially submembranous and laterally compressed ( Hippa 1990: 58)...................... M. crabroniformis group

Figures

Fig. 1. Locations on Crete, Greece where Milesia cretica Bot & van Steenis sp. nov. was observed (green circles) or collected (red circles).

Fig. 2. Milesia cretica Bot & van Steenis sp. nov. ♂, (SBH), habitus dorsal. Collected on Crete, Imbros Gorge, 17 October 2017, leg. and coll. S. Bot.

Fig. 3. Milesia cretica Bot & van Steenis sp. nov., paratype, ♀ (SBH), habitus dorsal. Collected on Crete, near Lakkoi, 9 October 2021, leg. and coll. S. Bot.

Fig. 7. Milesia cretica Bot & van Steenis sp. nov. (SBH), male genitalia in lateral view. Collected on Crete, Imbros Gorge, 17 October 2017, leg. and coll. S. Bot. Abbreviations: a = aedeagus; s = surstylus; sl = superior lobe. Scale bar = 1 mm.

Fig. 8. Type locality of Milesia cretica Bot & van Steenis sp. nov. with flowering Hedera helix L.: Imbros Gorge, Crete, Greece, October 8, 2021 (photo Sander Bot).

Fig. 4. Milesia crabroniformis (Fabricius, 1775), ♂, (SBH), habitus dorsal. Collected in France, Midi- Pyrénées, 4 August 2010, leg. and coll. S. Bot.

Fig. 9. Neighbour-Joining tree using the 658 bp COI sequences. Numbers at nodes indicate the bootstrap support values above 80. Each specimen name has the morphological identification, the country of origin and the GenBank Accession Number.

Fig. 6. Milesia virginiensis (Drury, 1773), ♂, (SBH), habitus dorsal. Collected in the USA, South Carolina, 3 September 2018, leg. and coll. S. Bot.