Conosiphon ianus Alvarez Fidalgo & van den Broek, 2023

van den Broek, Reinoud, Alvarez Fidalgo, Piluca & Smit, John, 2023, A new species of the genus Conosiphon Becker, 1923 and the first records of this genus for Europe (Diptera, Asilidae), ZooKeys 1181, pp. 59-79 : 59

Conosiphon ianus Alvarez Fidalgo & van den Broek sp. nov.

Figs 1 , 2 , 3 , 4 , 5 , 6

Examined material.

Type material. Holotype Almería, Spain • 1 ♂; Cabo de Gata; 36°49.3'N, 2°15.4'W, 20 m a.s.l.; 02.I.2022; F. Rodríguez leg.; MNCN_ Ent 344922; pinned . Paratypes Almería, Spain • 2 ♂; same collection data as for holotype • 5 ♀♀; same collection data as for holotype; pinned. The holotype, 1 ♂ paratype and 4 ♀♀, are stored in MNCN (MNCN_ Ent 344923-27), the remainder in PAFC. • 1 ♂; Aguadulce (Roquetas de Mar); 36°49.7'N, 2°35.2'W, 170 m a.s.l.; 03.XII.2015; F. Rodríguez leg. ; MNCN_ Ent 361026; pinned and dissected, genitalia stored in phial. • 1 ♂ + 1 ♀; same collection data; 25.XII.2015 ; RVDBC; pinned. • 3 ♂ + 3 ♀; same collection data; 01.XII.2016 ; RVDBC; pinned. • 3 ♂; same collection data; 11.XII.2016 ; RMNH; specimens in ethanol. • 2 ♂ + 2 ♀; same collection data; 21.IX.2017 ; 1 ♂ + 1 ♀ at ZMHB, 1 ♂ + 1 ♀ at USNM; pinned. • 2 ♂ + 1 ♀; same collection data; 07.XII.2017 ; PAFC; pinned. • 1 ♀; same collection data; 12.I.2019 ; PAFC; pinned. • 2 ♂; Almerimar (El Ejido); 36°41.7'N, 2°45.9'W, 40 m a.s.l.; 14.XII.2017; F. Rodríguez leg. ; MNCN (MNCN_ Ent 344928-29); pinned. • 2 ♂; Cabo de Gata; 36°49.6'N, 2°13.6'W, 30 m a.s.l.; 29.XI.2015; F. Rodríguez leg. ; RMNH; stored in alcohol. • 2 ♂ + 2 ♀; same collection data and date; RVDBC; pinned. • 1 ♂; El Parador ( Vícar); 36°49.2'N, 2°36.1'W, 115 m a.s.l.; 22.XI.2015; F. Rodríguez leg. ; RVDBC; pinned. • 1 ♂ + 2 ♀; same collection data; 05.I.2019; F. Rodríguez leg. ; PAFC; pinned. • 3 ♂ + 3 ♀; same collection data; 05.I.2020; F. Rodríguez leg. ; RMNH; in ethanol. • 1 ♂; Rambla Morales , Cabo de Gata; 36°49.6'N, 2°13.6'W, 30 m a.s.l.; 08.XII.2015; P. Álvarez leg. ; RMNH; in ethanol. • 1 ♂ + 1 ♀; Rambla del Aguila , Santa María del Águila (El Ejido); 36°49.0'N, 2°46.2'W, 380 m a.s.l.; 10.XII.2015; P. Álvarez leg. ; PAFC; pinned. • 1 ♂; Retamar , Cabo de Gata; 36°49.6'N, 2°13.6'W, 30 m a.s.l.; 08.XII.2015; P. Álvarez leg. ; RMNH; in ethanol. • 1 ♀; Sorbas ; 37°08.5'N, 2°02.6'W, 365 m a.s.l.; 01.I.2019; F. Rodríguez leg. ; MNCN_ Ent 344930; pinned. • 1 ♂; Tabernas; 36°49.2'N, 2°36.1'W, 115 m a.s.l.; 19.XI.2015; F. Rodríguez leg. ; MNCN_ Ent 361025; pinned and dissected, genitalia stored in phial .

Diagnosis.

Head proportionally large; facial protuberance strong and prominent, occupying most of the face, its upper margin very well developed, more than in any other species of Conosiphon ; ventral macrosetae of fore femora absent, only long and thin setae present; macrosetae of mystax very dense and at least as long as the antennae, or longer; legs entirely dark, only basal part of the tibiae narrowly pale coloured; acrostichal macrosetae long and abundant. Hypopygium with a small and pointy epandrial lobe on the dorsal inner side, just before the apex. Hypandrium with a blunt projection on hind margin.

Description.

Male (Figs 1 - 3 , 6 ). Length of the body: 9 mm, length of the wing: 6.5 mm. Head. Frons, facial protuberance, genae and occiput, covered with pale grey tomentum. Ocellar tubercle rather high, reaching eye level, and bearing several long and erect black piliform macrosetae. Frons with some much shorter mainly black true setae. Facial protuberance strong and prominent, occupying most of the face, its upper margin well developed; distance of the upper margin to antennal socket slightly shorter than the length of the pedicel. Mystax dense and black, consisting of black piliform macrosetae, as long as or even longer than the antennae, in the lower part mixed with very few pale ones. Eyes dark brown. Face narrow, its width somewhat less than half one eye. Short macrosetae placed on top of occiput black, some shorter and white ones on both sides. All setae on the back of the head white, longer on top, shorter behind, the lower occipital macrosetae and setae white and very long. Proboscis and palpi black, both with some white setae on tip.

Antenna black, covered with grey tomentum. Ratio scape: pedicel: flagellum, 2:1:5. Scape ~ 5 × longer than broad, cylindrical in lateral view and bearing some stiff white seta-like macrosetae dorsally; more and longer mainly black ones ventrally. Pedicel much shorter (~ 1/2 the length of the scape), conical (narrower on the base and broader apically) in lateral view, bearing only short and stiff black macrosetae on the apical area, both dorsally and ventrally. Flagellum bare and nearly as long as the two basal antennal segments together. Postpedicel ~ 3 × the length of the pedicel. Style three-segmented (1:4:1), bare and nearly half as long as the postpedicel, last segment very narrow.

Thorax. Antepronotal macrosetae pale, well developed and mixed with numerous pale setae. Postpronotal lobe with some longish white setae. Scutum, scutellum, and pleurae black, covered with dense brownish grey tomentum. Dusting less dense along the median line of the scutum, giving the appearance of having a dark middle band along the mesonotum. Mesonotal setae very thin, scattered, and black, some pale ones hardly noticeable. On the mesonotal line, five pairs of presutural dorsocentrals, and six or seven pairs of post-sutural ones. The post-sutural macrosetae are thinner in the prescutellar area, here similar to acrostical macrosetae. The acrostical macrosetae are black, slightly shorter and stouter than dorsocentral ones and more abundant than mesonotal setae. All macrosetae located over the mesonotal middle line from the pronotal area to the prescutellar area. Scutellar surface bearing several long and soft white setae; scutellar margin with four stout and very long black macrosetae (and a fifth central thick seta that might be considered a macroseta). Notopleural, supraalar, and postalar macrosetae long and black. Anepisternum and katepisternum almost bare, with only some isolated thin pale setae, and a few dark macrosetae-like setae on dorsal area of anepisternum. Anepimeron with a set of seven or eight pale dorsal macrosetae and katatergite with a row of seven or eight long pale macrosetae. Halteres brown.

Legs. Coxae heavily grey tomentose, with several long macrosetae and setae. Legs shiny black and thin, covered with short pale setae. Only the area of connection of femora and tibiae pale, with apex of femora and basal part of the tibiae both narrowly yellowish. No ventral macrosetae on fore femur, but long, thin, black and white setae are present. Macrosetae on femora, tibiae, and tarsi stout, predominantly pale on fore and mid legs, and predominantly black on the hind legs. Claws black. Pulvilli brownish yellow.

Wing. Hyaline, slightly darkened in the apical area. Costa with black fine setae. Veins dark brown, only pale brown on the basal area.

Abdomen. Abdomen black, covered with dense brownish grey tomentum, like the mesonotum; tomentum less dense on the dorsal area of each tergite, giving an appearance of having dark patches. Tergal setae whitish, except on the dorsal area of the tergites, where they are longer, thicker, and black. Tergite I with dorsal setae particularly longer, pale, and more erect on the basal part, black and more adpressed on the marginal area. Tergites II and III with shorter black setae dorsally and more adpressed than those on tergite I. Dorsal black setae even shorter and more adpressed on tergites IV-VIII. Tergites I-VI with two or three thick, very long, pale marginal macrosetae laterally. Sternite I with very long, erect and dense whitish filiform setae, sternite II bare, the remaining sternites with long, thin, erect white setae, but shorter than those on sternite I. Sternites IV-VII with a pair of long true macrosetae, not as strong as those on terga, directed outwards and placed near the margin of the sternites; on the remaining sternites, macrosetae thinner and hardly differentiated from the true setae.

Terminalia (Fig. 3 ). Hypopygium black, covered with stiff white setae. Phallus somewhat tubular, tapering at the tip (Fig. 3A, B ). Epandrium with a small, curved, and pointed lobe, located on the dorsal inner side, just before the apex (Fig. 3C ), simple in lateral view (Fig. 3D ). Gonostylus long, rounded at the tip, with a small depression in the middle (Fig. 3E ). Hypandrium with a blunt projection on hind margin, bearing thin white setae; anterior margin distinctly concave (Fig. 3F ).

Female (Figs 4 , 5 ). Very similar to male, slightly larger, only differs in that sternal macrosetae that are less developed and frequently black. The ovipositor is illustrated in Fig. 4C, D .

Variation.

The main variation involves the colouration of the wings of the males (Figs 1 , 2 , 6 ). It is remarkable that two colour forms coexist in all locations, one with hyaline wings (Fig. 2C ), which seem to be slightly commoner, and the other with darkened wings (Fig. 2D ), only hyaline on 1/3 of the basal area. Intermediate forms are rarely found, but they do exist. All females have hyaline wings. No relevant differences have been found in the genitalia of the males of both forms, nor do they differ in COI barcodes (see Fig. 11 and adjoining molecular analyses).

The number of dorsocentral macrosetae vary greatly, both in male and female, from 4-6 pairs of presutural, and six or seven pairs of postsutural ones, some thicker, some thinner, but always thinner on the prescutellar area, where they are approximately the same length or slightly shorter than the dorsocentrals (as mentioned in the description). It is remarkable that the number and position of the dorsocentral macrosetae are not even symmetrical within one single specimen.

The number of marginal scutellar macrosetae is very variable too in both sexes (2-6, sometimes 3 or 5, usually 4), and frequently some of them are slightly thinner and it is doubtful whether they can be considered macrosetae or not. Rarely one or two can be pale instead of black. Also, leg macrosetae are variable in colouration and in some specimens, occasionally the number of pale macrosetae on hind legs is higher than usual. Legs are entirely black or at most the knees are narrowly pale. There is no correlation between the dark-winged form and the darker colouration of the legs, nor for the clear-winged form and the lighter knees.

Size variation.

Length of the body: 8.5-9.5 mm, length of the wing: 6.0-6.5 mm.

Other material studied.

Type specimen of Conosiphon pauper (Becker, 1907). Holotype Algeria • 1 ♂ (Fig. 7A ); Algier IV, 52370; Dysm. Conosiphon pauper Beck det. Becker; Holotypus [red label]. Type specimen of Conosiphon similis Becker, 1923. Syntype Algeria • 1 ♀ (Fig. 7B ); El-Kantara, 52631; Conosiphon similis Beck; Typus [red label]. Both specimens studied through high resolution images provided by courtesy of Jenny Pohl, ZMHB .

Etymology.

The new species is named after the Roman deity Janus for two reasons: on the one hand, because Janus gives the name to the month of January, the peculiar flight period (mainly December and January) of this robber fly, and on the other hand, because Janus is represented showing two faces, expressed in C. ianus by the presence of two colour forms (clear-winged and dark-winged). The name ianus should be treated as a noun in apposition ( ICZN 1999).

Habitat, biology, and ecology.

The first evidence of the presence of this species dates back to the winter of 2009 (Fig. 1 ) when F. Rodríguez Luque photographed a peculiar looking male Asilinae in Roquetas de Mar. The typical habitat where he found the same species in later years consists of open ground with scarce bushy vegetation but with extensive esparto grass ( Stipa tenacissima ). This habitat is frequently found near the coast but can also be found in the interior, in ramblas and desertic areas with gypsiferous soil (Fig. 8 ).

Copulas were frequently observed, taking place always on the ground. Also, as occurs in other species of Asilidae , cannibalism was sometimes observed. Due to the limited number of hunting observations, little is known about their main prey. However, observations preserved in photographs exist of C. ianus feeding on Coleoptera , Diptera ( Bibio sp. (presumably Bibio gineri Gil Collado, 1932), Coenosinae , Musca sp., and Sarcophagidae ), Heteroptera , and Hymenoptera .

Distribution and phenology.

Up to this date, C. ianus Álvarez Fidalgo & van den Broek sp. nov. is only known from the province of Almería, southeastern Spain. It seems to be present in several coastal areas of the south of the province, being much more local in the east coast and in the semi-desertic interior of the province In order to provide a clearer view of the known distribution of this species, all available records were gathered and then located in a 5 × 5 km grid map of the province of Almería (Fig. 9 ). Records come from two sources, collected specimens and photographs taken in the wild uploaded to the online database BiodiversidadVirtual.org (2023). The locations of all the pinned specimens studied were already shown under the chapter 'Type material’. Suppl. material 1 provides information related to all material identified from photographs at BiodiversidadVirtual.org (2023). Only photographs where the specimens can be positively identified were used.

As can be seen from all the available records, this is a winter species. The earliest date it was found was 8 November and the latest 6 February. However, usually the first adults start to be seen in the third week of November. Normally, the peak of abundance occurs in December and the species is found still in good numbers till middle January. Numbers decline rapidly in the third week of January and the species is rarely seen during the first week of February. Fig. 10 shows the phenology of the species (based on the available records) in a graphic.

Molecular analysis.

Due to presence of two distinct morphological forms within the range of C. ianus sp. nov. (e.g., the colouration of the wings in the male), we analysed 12 specimens, including nine males: four clear-winged forms and five dark-winged forms. All specimens clearly group together in one clade, separate from other taxa in all analyses executed: Neighbour-Joining, Minimum Evolution and Maximum Likelihood. The results are presented in a Neighbour-Joining tree (Fig. 11 ), full details of the specimens of C. ianus sp. nov. used for DNA barcoding are provided as a supplementary.xlsx file (Suppl. material 2). There is considerable variation among the barcodes of C. ianus sp. nov. with three groups consistently resolved with bootstrap values of 100 and 98 respectively and an average K2P distance of 1.7% (0.9-2.3). The average distance among all Asilinae species included in the analyses is 19.8% (4.0-27.7). The three groups within C. ianus sp. nov. do not comply with the differences in wing colouration among the males, as indicated in Fig. 11 : clear-winged (blue), dark-winged (red). Therefore, although there is considerable variation among the barcodes of C. ianus sp. nov., we consider it to be a single variable species with two distinct colour forms in the males. Future analyses, including DNA barcodes of other congeneric species, should resolve whether or not C. ianus sp. nov. is indeed one single species or perhaps a complex of species.

Figures

Figure 1. Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov. Male (clear-winged form) in its natural habitat, El Parador (Roquetas de Mar), Almeria, Spain, 25 - XII- 2009. Photograph: F. Rodriguez Luque.

Figure 2. Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov., male holotype (MNCN _ Ent 344922) A habitus in dorsal view B habitus in lateral view Male paratype of the clear-winged form (PAFC) C wing. Male paratype of the dark-winged form (PAFC) D wing. Scale bars: 5 mm (A, B); 3 mm (C, D). Photographs: PAF.

Figure 3. Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov., male terminalia A phallus in dorsal view B phallus in lateral view C right epandrium in dorsal view D right epandrium in lateral view E left gonocoxite and gonostylus in lateral view F hypandrium. Drawings: M. Trillo Camprodon.

Figure 4. Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov. Female paratype (MNCN _ Ent 344924) A habitus in dorsal view B habitus in lateral view Female paratype from Aguadulce in PAFC C Ovipositor, dorsal view D ovipositor, lateral view. Scale bars: 5 mm (A, B); 1 mm (C, D). Photographs: PAF.

Figure 5. Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov. Female in its natural habitat, Aguadulce (Roquetas de Mar), Almeria, Spain, 7 - XII- 2015. Photograph: PAF.

Figure 6. Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov. Male (dark-winged form) in its natural habitat, Aguadulce (Roquetas de Mar), Almeria, Spain, 7 - XII- 2015. Photograph: PAF.

Figure 7. A holotype of Conosiphon pauper (Becker, 1907), male habitus in lateral view B syntype of Conosiphon similis Becker, 1923, female habitus in lateral view. Scale bars: 5 mm. Photographs: E. Wolff, courtesy of J. Pohl, ZMHB.

Figure 8. Four locations showing the habitat of Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov. in the province of Almeria, Spain A type location in Cabo de Gata B aguadulce C vicar D almerimar. Photographs: F. Rodriguez Luque.

Figure 9. Distribution map of Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov. in Spain, created from all available data, both collected specimens and published photographs. Map: M. Alvarez Fidalgo.

Figure 10. Graphic showing the flight period of Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov., based on the 105 records gathered from collections and photographs. Graph: M. Alvarez Fidalgo.

Figure 11. Neighbour-Joining tree for Conosiphon ianus Alvarez Fidalgo & van den Broek, sp. nov., and related genera of the subfamily Asilinae. Laphria flava (Linnaeus, 1761) is used as an outgroup. Red indicates dark-winged males and blue indicates clear-winged males of C. ianus.