Pteremis canaria ( Papp, 1977 )

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 : 176-181

Pteremis canaria ( Papp, 1977)

( Figs 75–78 , 81–97 )

Leptocera (Pteremis) canaria Papp, 1977: 126 (both sexes, illustr.). Type locality: Canary Islands, Tenerife, Mte Realejo Alto. HT male (ULCI). Pteremis canaria : PAPP (1982): 130 (generic combination); PAPP (1984): 87 (Palaearctic catalog); RoHÁĆFK et al. (2001):210 (World catalog); RoHÁĆFK et al. (2003): 61 (additional records).

Type material examined. HoLoTYPF: J ( ULCI), labelled:‘TENERIFE, Mte Realejo Alto, I-76, ≠ M. Baez ≠’ (obverse) and ‘ex larva Boletus sp. ’ (reverse) and ‘ Holotypus L. (Pteremis) canaria L. Papp J’ (red-framed label with red printed ‘Holotypus’) (see Fig. 77 ). The specimen is intact, but immature ( Fig. 75 ), minutia-pinned on oblong card. PARATYPFs: SPAIN: CANARY ISLANDS: TENERIFE: 1 J, ‘TENERIFE, Las Lagunetas, 25-I-74, ≠ M. Baez ≠’ (obverse), ‘ex - larva on „ Boletus “’ (reverse) (immature specimen with abdomen mounted on microslide pinned below specimen, ULCI); 1 J, ‘TENERIFE, Cumbre de Realejo Bajo, 1-11-73, M. Baez’ ( HNHM, genit. prep.). Both paratypes with type and determination labels as in holotype but with red printed ‘Paratypus’. Paratype ♀ (not examined), with same data as the above paratype male from Las Lagunetas ( HNHM, see PAPP 1977: 126).

Additional material examined. SPAIN: CANARY ISLANDS: TENERIFE: Las Lagunetas, 29.i.1974, 1♀ ex larva on Boletus , 19.xii.1973; Tenerife, Realejo Alto, 19.ix.1978, 1♀, both M. Baez leg. ( ULCI); Tenerife,Aguamansa nr. Orotava 1 km S, sweeping vegetation along brook in ravine, 12.v.1999, 2 ♀♀ (1 ♀ genit. prep.), J. Roháček leg. ( SMOC).

Redescription. Male. Because the holotype and one male paratype are immature, pale-pigmented specimens, the only other available male (paratype from HNHM) can be used for description of colour characters. Total body length 1.59–1.79 mm; general colouration and microtomentum of body as in P. fenestralis , or somewhat lighter, brown to dark brown.

Head (cf. Figs 75, 76 ) almost 1.6× higher than long (thus shorter than in P. fenestralis ), darker posterodorsally, paler anteroventrally. Frontal pattern is characterized by pale brown (to ochreous) orbits, interfrontalia and frontal triangle, and darker (blackish brown) stripes surrounding them and almost forming M-shaped mark; also occiput dark brown and all frons grey microtomentose, only interfrontalia with microtomentum lighter, pale to silvery grey; frontal triangle pale as orbits, thus well delimited and reaching to anterior fourth or fifth of frons; anterior margin of frons brown, in contrast to pale ochreous or dirty yellow frontal lunule. Face usually dirty yellow (but it can be unnaturally darkened in some specimens), whitish grey microtomentose; medial carina poorly developed as in P. fenestralis . Gena yellowish ochreous and all microtomentose and separated from occiput by dark glossy perpendicular stripe on postgena (as in P. fenestralis ). Cephalic chaetotaxy closely resembling that of P. fenestralis but differing as follows: pvt minute (smaller than in P. fenestralis ) but with apices meeting medially; occi longer than occe but markedly shorter than vti; 3 ifr, two anterior pairs longer and more robust, and sometimes with 1 microseta in front of anterior ifr; g usually longer than anterior peristomal setula and 1 or 2 setae behind as long as peristomals; vi very long and robust, often slightly longer than vti; about 5 sparse peristomal setulae being almost as long as 2 postgenal setae. Eye subcircular (18:17), with longest diameter about 4 times as long as smallest genal height.Antenna with scape and 1 st flagellomere only slightly lighter than pedicel; 1 st flagellomere and arista similarly ciliate as those of P. fenestralis , the latter about 3.8 times as long as antenna.

Thorax dark brown to ochreous and grey microtomentose; mesonotum dark brown but humeral callus and notopleural area pale brown to ochreous; pleuron brown to (sternopleuron) pale brown, sutures between pleural sclerites and also ventral corner of sternopleuron can be pale ochreous. Scutellum large, flat and formed as in P. fenestralis . Thoracic chaetotaxy as in P. fenestralis but 1 hu longer than anterior npl; 1 prs as long as anterior npl and 1 shorter sa; the outer pa as long as dc, the latter relatively longer than that of P. fenestralis ; 4 or 5 dc microsetae in front of dc distinctly longer than ac microsetae; 6 or 8 rows of ac microsetae on suture; 2 very long and robust sc, laterobasal longer than that of P. fenestralis because apical sc only 1.2‒1.4 times as long as laterobasal; only 1 distinct and very long stpl because anterior stpl is reduced to a hardly visible microsetula or is absent.

Legs (in contrast to those of P. fenestralis ) uniformly coloured, ochreous to brown, with trochanters, tibiae and tarsi very little or not paler than femora and coxae (cf. Fig. 76 ); tibiae not variegated, i.e. without lighter basal and apical ends. Chaetotaxy of femora and tibiae as in P. fenestralis but t 2 ventrally (see Figs 95, 97 ) with only 2 setae, 1 long and strong vpa and 1 short and weak av near middle, i.e. va seta absent; dorsally ( Fig. 96 ) with the same setae as in P. fenestralis but distal anterodorsal seta longer; apex of tibia provided with only 2 short (1 longer) subapical setae anteriorly ( Fig. 97 ) and 2 posteriorly ( Fig. 95 ). Mid basitarsus (mt 2) often with 1 enlarged ventral setula (see Fig. 97 ). Ratio t

2

: mt

2

= 1.85–1.94.

Wing always normally developed (cf. Fig. 78 ). Membrane distinctly brownish fumose, more darkened along some veins. Wing relatively broad, with venation closely resembling that of the macropterous form of P. fenestralis but C less produced beyond apex of R 4+5, the sinuate A 1 darker pigmented and alula with apex more rounded. Wing measurements: length 1.54–1.69 mm, width 0.66–0.73 mm, C-index = 0.81–0.92, r-m\dm-cu: dm-cu = 1.85–2.08. Haltere with pale ochreous stem and brown knob having often lightened apex.

Abdomen constructed, coloured and setose similarly as that of P. fenestralis but slightly differing as follows: T1+2 (largest tergum) posteriorly as wide as or slightly wider than T3. Seta in posterior corner of T5 very long and robust, longer than this sclerite. S1+2 (or S2) larger, posteriorly as wide as S3 anteriorly, ochreous in contrast to all subsequent abdominal sterna. S5 ( Fig. 84 ) distinctly shorter than S4 and also somewhat shorter and more transverse than that of P. fenestralis , characterized by short and sparsely micropubescent pale area in front of posteromedial comb of more numerous and denser spines; setae laterally surrounding posteromedial pale area and also those on lateral parts of S5 relatively sparse. Postabdominal sterna (S6–S8) very similar to those of P. fenestralis including setae.

Genitalia. Epandrium ( Figs 81, 82 ) somewhat shorter and narrower in caudal view ( Fig. 81 ) and anal fissure distinctly wider and more rounded than in P. fenestralis . Cerci distinguished by characteristic micropubescence (in two separate groups: on convex posteromedial part and on distal part), medially separated with relatively short but very narrow incision. Each cercus terminated by a small rounded and bare lappet (see Fig. 83 ) and with 1 long sinuate subventral seta, 1 shorter seta more dorsally and 2 short setae near apex, close to above lappet. Medandrium low (short) and broad as in P. fenestralis but with posteromedial part not darker than other parts of sclerite ( Fig. 81 ). Hypandrium with distinctly longer and somewhat curved but also strongly asymmetrical flattened anterior apodeme ( Fig. 82 ). Gonostylus ( Figs 82, 85 ) having anterior lobe without projecting anterodorsal process, with only a corner (cf. Fig. 82 ), 3 curved anteroventral setae more robust, and posteriorly directed ventral projection spiky jagged and pale-pigmented ( Fig. 85 ); posterior lobe of gonostylus differing from that of P. fenestralis by shorter and more robust seta on posterior subconical process (see Fig. 86 ). Aedeagal complex ( Fig. 87 ) with phallophore more acute ventrally, distiphallus (dorsoventrally) distally dilated and postgonite distally elongately spatulate, with apex rounded; its minute anterodorsal sclerite (= remnant of pregonite) very small. Ejacapodeme also very small, as in P. fenestralis .

Female. Head, thorax, legs and wings as in male unless mentioned otherwise below. Total body length 1.82–2.26 mm. Body colouration (thorax in particular) somewhat darker ( Fig. 76 ). Anterior fourth or third of frons sometimes (seen in one specimen) orange ochreous and concolorous with frontal triangle, interfrontalia and orbits. Frons with 3 or 4 ifr setae and ads more distinct. Prescutellar ac microsetae (2 pairs) often somewhat enlarged (as in P. fenestralis ) and anterior stpl sometimes represented by well-developed microseta. Mid basitarsus relatively longer: ratio t 2: mt 2 = 1.71–1.80. Wing measurements: length 1.91–2.04 mm, width 0.83–0.91 mm, C-index = 0.87–1.08, r-m\dm-cu: dm-cu = 1.88–2.31. Abdomen generally as in P. fenestralis but S1+2 longer and wider (as in male), with reduced setosity; S3 and S4 subequal in length and S5 distinctly shorter than S4 (only slightly longer than S1+2).

Postabdomen ( Figs 88–90 ) generally similar to that of P. fenestralis but with T6 and T7 more transverse ( Fig. 89 ), the latter with pale posterior margin; T8, on the contrary, longer and less transverse (and more distinctly micropubescent) and T10 more rounded ( Fig. 89 ). T7 and S7 almost meeting laterally ( Fig. 88 ). S6 more suboblong, markedly narrower than T6 and with pale-pigmented posterior margin; S7 only a little narrower than S6 ( Fig. 90 ) dark-pigmented but with marginal pale-pigmented posterior band. S8 ( Figs 90 , 91 ) distinctive, longer than broad, pale-pigmented both anteriorly and posteriorly, with more but fine setae in the middle, and with a posteromedial group of 6 (2 more lateral long, 4 medial short) setae on elevated sockets ( Fig. 91 ). S10 (in largest extension) wider than S8, more elongate and tapered posteriorly than that of P. fenestralis , and with projecting anterolateral corners ( Figs 88 , 93 ), setose along posterior margin including 2 long setae. Spectacles-shaped sclerite represented by distinct but unpigmented ovoid rings ( Fig. 92 ). Spermathecae 2+1 ( Fig. 94 ) blackish, pyriform, each having basal conical part separated from spherical body by 3 or more transverse (usually incomplete) rings; terminal parts of ducts long, but thicker than those of P. fenestralis and those of paired spermathecae connected close to body of spermatheca. Cerci ( Figs 88, 89 ) relatively robust and rather conical, only slightly dorsoventrally flattened (see Fig. 88 ) in contrast to those of P. fenestralis .

Comments. Pteremis canaria was originally described from a series collected by M. Báez in Tenerife ( PAPP 1977). However, it was later also recorded from two other islands of the Canarian archipelago, viz. Gran Canaria ( PAPP 1982) and El Hierro ( PAPP 1982, RoHÁĆFK et al. 2003). During this study specimens from El Hierro proved to belong to a different species, P. ferreus sp. nov., described below. Unfortunately, the only specimen (male) recorded by PAPP (1982) from Gran Canaria (Barranco de Firgas) has not been traced so that its true identity remains unknown; it could possibly represent another unnamed species.

Pteremis canaria is best characterized by pale brown (to ochreous) orbits, interfrontalia and frontal triangle, entire absence of va seta on t 2 ( Fig. 97 ), S5 ( Fig. 84 ) with short, broad and sparsely micropubescent pale area in front of posteromedial comb spines, male cercus with micropubescence in two separate groups ( Fig. 81 ) and ventroapically with small rounded and bare lappet ( Fig. 83 ), anterior part of gonostylus with ventral projection unusually spiky jagged and pale-pigmented ( Fig. 85 ), female S8 ( Figs 90 , 91 ) longer than broad and with more fine setae in the middle than in relatives and spermathecae pyriform, with 3 or more transverse surface rings.

The shape and structure of female S8 and of spermathecae indicate affinity of P. canaria to P. pulliceps sp. nov; also apex of ventral process of anterior lobe of gonostylus can be considered similar in both species, in having apex more or less spiky (cf. Figs 48 and 85 ).

Biology. All eight specimens of P. canaria hitherto found in Tenerife were collected in native pine ( Pinus canariensis ) forests ( Figs 79, 80 ), including those (2 JJ 2 ♀♀) reared from larvae found in sporocarps of Boletus sp. (M. Báez, personal communication, 2023). Hitherto, no specimens of this species have been found in laurel forests in Tenerife despite much collecting effort in this habitat (cf. RoHÁĆFK et al. 2003). Consequently, P. canaria seems to really be closely associated with Pinus canariensis forests and probably develops in fungi.

Distribution. Canary Is.: Tenerife. P. canaria is to be considered endemic to Tenerife I. The Pteremis specimens from El Hiero proved to belong to a different species (see below) while specimen from Gran Canaria requires revision (see above).

Figures

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).

Figs 81–87. Pteremis canaria (Papp, 1977), male, paratype. 81 – external genitalia, caudally (aedeagal complex and left gonostylus omitted); 82 – ditto, left laterally; 83 – apical parts of cerci, ventrocaudally; 84 – male S5, ventrally; 85 – gonostylus, left sublaterally; 86 – posterior lobe of gonostylus, left laterally; 87 – aedeagal complex, laterally. Scales = 0.1 mm (Figs 81, 82, 84, 87), 0.05 mm (others).

Figs 88–90. Pteremis canaria (Papp, 1977), female (Tenerife, Aguamansa nr. Orotava). 88 – postabdomen, laterally; 89 – ditto, dorsally; 90 – ditto, ventrally. Scale = 0.1 mm.

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 46–51. Pteremis pulliceps sp. nov., male, paratype. 46 – external genitalia, left laterally; 47 – ditto, caudally (aedeagal complex and left gonostylus omitted); 48 – gonostylus, laterally; 49 – apex of cercus, left laterally; 50 – aedeagal complex, laterally; 51 – male S5, ventrally. Scales = 0.05 mm (Figs 46, 47, 50), 0.03 mm (Figs 48, 49), 0.1 mm (Fig. 51).