Pteremis ferreus, Roháček, 2024

Roháček, Jindřich, 2024, The genus Pteremis (Diptera: Sphaeroceridae) in the West Palaearctic area, with description of four new species, Acta Entomologica Musei Nationalis Pragae 64 (1), pp. 153-206 : 182-187

Pteremis ferreus sp. nov.

( Figs 98–102 , 104–118 )

Pteremis canaria (in part.): PAPP (1982): 130 (record from El Hierro, misidentification); RoHÁĆFK et al. (2003):62 (record from El Hierro, misidentification).

Type material. HoLoTYPF: J ( ULCI), labelled: ‘HIERRO, Raya de Llanía, 9-V-99, M. Báez’ (partly handwritten), ‘ Pteremis canaria Papp J, J. Roháček det. 2000’, ‘ HOLOTYPUS J, Pteremis ferreus sp. n., J. Roháček des. 2023’ (red label) ( Fig. 100 ). The specimen (see Figs 98, 99 ) is intact, dry mounted on minutia pinned to rectangular card. PARA- TYPFs: SPAIN: CANARY ISLANDS: EL HIERRO: 1 JJ 4 ♀♀ (1 J 2 ♀♀ genit. prep.), with same data as for holotype (1 J 2 ♀♀ SMOC, 2 ♀♀ ULCI); 1 J (immature, mid leg mounted on microslide, pinned below specimen), labelled:‘Can.Hierro, El Pinar,27. 3. 50, Lindberg’ ( MZHF). All paratypes with yellow label ‘ PARATYPUS J or ♀, Pteremis ferreus sp. n., J. Roháček des. 2023’.

Description. Male ( Figs 98, 99 ) closely resembling P. fenestralis and P. canaria , in particular. Total body length 1.97–2.10 mm; general colour as in both these species but head (lower parts in particular) darker.

Head ( Figs 98, 99, 101 ) about 1.45× higher than long. Frons dark brown to blackish except for orange-brown or reddish brown anterior margin. Microtomentose pattern well developed, including silvery grey glittering orbits, interfrontalia and frontal triangle and dull blackish brown M-shaped mark surrounding them (see Fig. 101 ); frontal triangle narrow and almost reaching anterior margin of frons. Extent of reddish or orange-brown colouration of frontal margin rather variable, narrow (as in Fig. 101 ) to extend over anterior third of frons and also including anterior corner of frontal triangle. Frontal lunule more or less concolorous with anterior frontal margin and face, but seemingly paler due to light grey microtomentum. Face orange-brown to brown, usually lighter at ventral margin, grey microtomentose; medial carina better developed than in P. fenestralis , distinct also more ventrally. Gena reddish brown to brown, usually darker than face, particularly posteriorly, grey microtomentose; shining dark postgenal stripe as in other species. Cephalic chaetotaxy (cf. Fig. 101 ) very similar to that of P. fenestralis but pvt yet smaller, with apices not meeting medially; occi longer than occe and nearly parallel (hardly inclinate) and about two-thirds of vti; vti normally longer (sometimes distinctly) than vte; posterior ors as long as or longer than oc (sometimes as long as vte) and about 1.4 times as long as anterior ors; 4 ifr, two middle pairs distinctly longer, more robust and usually crossed medially; g short but usually longer and more robust than anterior peristomal setula. Eye subcircular (10:9), with longest diameter about 5 times as long as smallest genal height hence gena lower than that of P. fenestralis . Antenna with scape brown to pale brown, pedicel and 1 st flagellomere blackish brown. Arista about 3.8 times as long as antenna, very shortly and densely ciliate.

Thorax generally coloured and microtomentose in P. fenestralis , including brown (not ochreous) notopleural area (in contrast to that of P. canaria ) but not only sutures between pleural sclerites ochreous but also sternopleuron distinctly paler than other pleural sclerites. Thoracic chaetotaxy: mesonotal macrosetae somewhat longer than in P. fenestralis ; 1 hu, anterior npl and, particularly, prs distinctly longer (the latter only slightly shorter than hu markedly longer than sa); outer pa as long as dc but inner pa distinctly longer than those of P. fenestralis and P. canaria ; dc microsetae (in front of dc) more enlarged, 2.5–3 times as long as ac microsetae and also the latter longer than in P. fenestralis ; both sc very long and robust, laterobasal sc as long as or almost as long as apical sc (longest thoracic seta); only 1 long (posterior) stpl because anterior stpl reduced to a hardly visible hair.

Legs coloured similarly as those of P. fenestralis but usually only fore leg with knee yellowish ochreous, t 2 and t 3 unicolorous brown. Pedal chaetotaxies differing from those of P. fenestralis as follows: f 2 anteriorly with a short row of 3 distinct subapical setae, the most distal longest. t 2 chaetotaxy ( Figs 116–118 ) most similar to that of P. canaria (cf. Figs 95–97 ) but distinguished by strongly reduced but present va seta ( Fig. 118 ), 3 short setae dorsally above distal pair of long setae ( Fig. 117 ), proximal posterior short seta situated more distally (almost at level of short av seta, cf. Figs 116, 117 ) and apex of t 2 posteriorly with 3 small setae ( Fig. 118 ). Mid basitarsus (mt 2) usually without enlarged ventral (or anteroventral) setula ( Fig. 118 ). Ratio t 2: mt 2 = 1.75–1.80.

Wing normally developed ( Fig. 102 ), most resembling that of P. canaria (with C less produced beyond apex of R 4+5 and A 1 darker pigmented) but relatively (length compared to width) shorter, also dm cell somewhat shorter and membrane yet more darkened along veins (cf. Figs 78 and 102 ). Wing measurements: length 1.87–1.93 mm, width 0.83–0.85 mm, C-index = 1.03–1.05, r-m\dm-cu: dm-cu = 1.94–2.14. Haltere bicolorous, with pale ochreous to yellow stem and brown knob, the latter more slender than that of P. fenestralis .

Abdomen generally formed and coloured as P. fenestralis but T1+2 longer, about 1.6 times as long as T4; T3 not wider than T1+2; T4 narrower but slightly longer than T3; S1+2 longer and wider (similar to that of P. canaria ); both S3 and S4 large, trapezoidal (wider posteriorly); S3 narrower but slightly longer than S4. S5 ( Fig. 108 ) as broad as but shorter and more transverse than S4, with large pale-pigmented and finely micropubescent semicircular area (much larger than in P. canaria ) in front posteromedial comb of spines, being widest of all those in Pteremis species and composed of dense fine spines; lateral setae of S5 fine but more numerous than in P. canaria . S6+7 as in P. fenestralis , but with 2 + 2 setae finer and S8 dorsally with a pair minute microsetae.

Genitalia. Epandrium ( Figs 104, 105 ) resembling that of P. canaria but with setae denser and finer, more asymmetrical in caudal view ( Fig. 104 ), and anal fissure more narrow, elongately ovoid, thus tapered dorsally. Cerci large, each dorsally laterally somewhat bulging ( Fig. 104 ) and ventrally flattened, projecting into distinctive ventromedial flat but acutely pointed and bare apex ( Figs 104, 105 ). Medandrium medially long, narrowly darkened and reaching almost to apex of cerci ( Fig. 104 ). Hypandrium with apodeme distinctly longer than in P. fenestralis , thus more similar to that of P. canaria but less flattened. Gonostylus ( Figs 104–106 ) very characteristic, unlike all other W Palaearctic species its anterior lobe with anterodorsal process extremely long, far projecting (almost) dorsally ( Fig. 106 ); also division of anterior lobe of gonostylus into anterodorsal pale part and posteroventral dark-pigmented and strongly sclerotized part very characteristic; the latter part ventrally with 2 strong curved setae and 1 robust, darkened, posteriorly directed projection with simply pointed apex ( Fig. 106 ); posterodorsal part of anterior lobe pale-pigmented and also more or less separate, carrying usual oblique longitudinal spinulose ledge. Posterior lobe (see Fig. 106 ) relatively small, hidden behind anterior lobe because situated medially (cf. Fig. 104 ) and terminated by robust blunt spine and 2 or 3 fine subapical setae; its posterior subconical process robust and projecting more ventrally than main part, with 1 usual, medially curved seta on apex. Aedeagal complex ( Fig. 107 ) constructed similarly as in other Pteremis species, characterized by combination of relatively robust phallophore with blunt (ventral) apex, proximally strongly tapered and distally strongly dilated distiphallus having a small finely haired area in middle part of its dorsal side. Postgonite sinuate in lateral view as that of P. fenestralis but its dilated apex different, rather shortly lancet-shaped than knob-like, and minute anterodorsal sclerite (= remnant of pregonite) with 2 fine setulae. Ejacapodeme not observed.

Female. Similar to male unless mentioned otherwise. Total body length 2.02–2.26 mm. Mid basitarsus (mt 2) sometimes with 1 slightly enlarged ventral setula in proximal fourth; mt

2

longer on the average: ratio t

2

: mt

2

= 1.78–1.80. Wing measurements: length 1.73– 195 mm, width 0.77–0.85 mm, C-index = 0.91–1.06, r-m\dm-cu: dm-cu = 1.53–1.87.

Abdomen resemblingthatof P.fenestralis but T1+2 longer (about 1.7 times as long as T3); T3 somewhat narrower than T1+2; T5 distinctly longer than T4; S1+2 longer and wider, S3 and S4 subequal in length and S5 distinctly shorter than S4 (as those of P. canaria ); S3 narrower than S4 and more trapezoidal; S5 only slightly narrower than S4 and posteriorly somewhat tapered, thus not transversely oblong but trapezoidal, with rounded corners.

Postabdomen ( Figs 109–111 ) also similar to those of P. fenestralis and P. canaria . T6 transversely subtrapezoidal and yet wider than that of P. canaria but with posterior margin pale-pigmented; T6 and T7 ( Fig. 110 ) with more setae than those of both these relatives and lacking pale posterior marginal stripe. T8 with dorsomedial part relatively broad, pale-pigmented and micropubescent in only posterior half (membranous areas between the latter and dark lateral parts without micropubescence - Fig. 110 ). T10 slightly longer than broad, roughly pentagonal and its posterior half micropubescent ( Fig. 110 ). S6 more transverse and uniformly pigmented as in P. fenestralis but with richer setae ( Fig. 111 ). S7 entirely dark-pigmented ( Figs 109, 111 ), larger, wider and more setose than that of both P. fenestralis and P. canaria . S8 species-specific ( Figs 111 , 112 ), transversely semioval, with only 2 pairs of setae (lateral longer) and micropubescence sparse and restricted to small posteromedial area of anterior pigmented part; posterior membranous part provided with a medial group of 2 long sinuate and 4 short setae between them, all on elevated sockets ( Fig. 112 ). S10 (in largest extension) only slightly narrower than S8, transversely subpentagonal, but anteriorly broadly emarginate (deeper than in P. fenestralis ), largely micropubescent and relatively long but finely setose in front of posterior margin ( Fig. 114 ). Spectacles-shaped sclerite ( Fig. 113 ) developed as a pair of unpigmented, irregularly ovoid rings, most similar to those of P. canaria . Spermathecae 2+1 most resembling those of P. canaria , pyriform, but having basal conical part separated from ovoid body by only 1 complete ring-shaped ledge; terminal parts of ducts formed as in P. canaria but those of paired spermathecae more divergent (see Fig. 115 ). Cerci ( Figs 109, 110 ) robust and subconical, thus resembling those of P. canaria including setosity.

Etymology. The name is a Latin adjective ferreus (= iron, ferrous, but also meaning hard) and is derived from El Hierro (= iron in Spanish), the island from which the new species originates and also refers to the hard, heavily sclerotized ventral process of the anterior lobe of its gonostylus.

Comments. Pteremis ferreus sp. nov. externally resembles P. canaria in having strongly reduced va seta on the mid tibia ( Fig. 118 ) but it differs from this and other Pteremis species as follows: male S5 armed by a very wide posteromedial comb of dense spines ( Fig. 108 ), apex of male cercus flat but acutely projecting ( Fig. 104 ), anterior lobe of gonostylus somewhat tripartite and with anterodorsal process extremely long and projecting dorsally, and its ventral projection robust, dark, simply pointed ( Fig. 106 ), distiphallus dorsoventrally strongly dilated but with micropubescence restricted to small dorsal area ( Fig. 107 ). Female P. ferreus is best characterized by the transversely semioval shape of S8 ( Fig. 112 ) and spermathecae with the basal conical part separated from the ovoid body by only 1 complete ring-shaped ledge ( Fig. 115 ). Spermathecal structures suggest a relationship to P. pulliceps , P. canaria and (possibly) P. apterina , as discussed above under P. pulliceps . The long anterodorsal process of the anterior lobe of the gonostylus is similar to that of the Nearctic P. wirthi (see below) but the latter species is considered more closely allied to P. fenestralis (see comments above under this species).

Biology. Six type specimens were collected by sweeping undergrowth of native laurel forest ( Fig. 103 ) in the protected area Raya de La Llanía in the central montane part of El Hierro I. in May 1999 (M. Báez, personal communication, 2023). The remaining (immature) paratype was captured in March.

Distribution. Canary Is.: El Hierro. Apparently, P. ferreus is endemic to this island.

Figures

Figs 98–103.Pteremis ferreus sp. nov. and its habitat. 98 – male, holotype, left laterodorsally; 99 – ditto, right lateroventrally; 100 – labels of the holotype; 101 – head and thorax of the holotype, subdorsally; 102 – right wing, male paratype; 103 – laurel forest (Laurisilva) in type locality (El Hierro, La Llanía), habitat of the species. Scales = 0.5 mm (Figs 98, 99, 102), 0.3 mm (Fig. 101). Photo by E. García (103) and J. Roháček (others).

Figs 104–108. Pteremis ferreus sp. nov., male, paratype. 104 – external genitalia, caudally (aedeagal complex and left gonostylus omitted); 105 – ditto, left laterally; 106 – gonostylus, left laterally; 107 – aedeagal complex (with aedeagus separated), laterally; 108 – male S5, ventrally. Scales = 0.1 mm (Figs 104, 105, 107, 108), 0.05 mm (Fig. 106).

Figs 109–111. Pteremis ferreus sp. nov., female, paratype. 109 – postabdomen, laterally; 110 – ditto, dorsally; 111 – ditto, ventrally. Scale = 0.1 mm.

Figs 112–118. Pteremis ferreus sp. nov., male and female, paratypes.112 – S8, ventrally; 113 – spectacles-shaped sclerite, ventrally; 114 – S10, ventrally; 115 – spermathecae; 116 – male left t2 and mt2 posteriorly; 117 – ditto, dorsally; 118 – ditto, anteriorly.Scales = 0.05 mm (Figs 112–115), 0.2 mm (others).

Figs 91–97. Pteremis canaria (Papp, 1977), female (Tenerife, Aguamansa nr. Orotava). 91 – S8, ventrally; 92 – spectacles-shaped sclerite, ventrally; 93 – S10, ventrally; 94 – spermathecae; 95 – left t2 and mt2 posteriorly; 96 – ditto, dorsally; 97 – ditto, anteriorly. Scales = 0.05 mm (Figs 91–94), 0.2 mm (others).

Figs 75–80. Pteremis canaria (Papp, 1977) and its habitats. 75 – male, holotype, left laterally; 76 – female (Canary Is, Tenerife,Aguamansa nr. Orotava), left laterally; 77 – labels of the holotype (locality label with obverse and reverse); 78 – right wing, female (from Aguamansa); 79 – valley of a dry brook in a pine forest, habitat of P. canaria near Aguamansa; 80 – pine forests (Pinus canariensis) in the vicinity of Aguamansa. Scales = 0.5 mm. Photo by M. Deml (76) and J. Roháček (others).