Pteremis vlasovi ( Duda, 1938 ), 2024

Pteremis vlasovi ( Duda, 1938) View in CoL comb. nov.

( Figs 149–167 View Figs 149–151 View Figs 152–157 View Figs 158–161 View Figs 162–164 View Figs 165–167 )

Limosina (Paraspelobia) Vlasovi Duda, 1938: 96 (both sexes, illustr.). Type locality: Turkmenistan, Ashkhabad env. Lectotype:J (designated by RoHÁĆFK 1983: 230) (ZISP).

Paraspelobia vlasovi View in CoL : RoHÁĆFK (1983): 230–232 (generic combination, redescription,illustr.); PAPP (1984):87 (Palaearctic catalog); RoHÁĆFK et al. (2001): 189 (world catalog).

Type material examined. LFCToTYPF (designated by RoHÁĆFK 1983): J ( ZISP), labelled (in Russian handwritten alphabet, cf. Fig. 150 View Figs 149–151 ): ‘okr. Ashkhabada 28.II.32 Vlasov’, ‘Bugristye peski, glubokaya raskopka nory Sp. lept.’, ‘ Paraspelobia Vlasovi Duda J d. Duda’ (handwritten by O. Duda) and ‘ Lectotypus J, Paraspelobia vlasovi Duda, J. Roháček des. 1980’ (red-framed label) (intact). PARALFCToTYPFs (examined by RoHÁĆFK 1983): 7 JJ 6 ♀♀, with same data as for lectotype; 2 JJ 1 ♀, labelled: ‘okr. Ashkhabada 18.III.933 Vlasov’, ‘Bugrist. peski, v nachale Sp. lept.’; 1 ♀, labelled: ‘19 23/IV nora Rhombomys opimus Licht. , Vlasov’. All deposited together with about 40 additional type specimens (to be considered paralectotypes) in ZISP. There are 11 more type specimens (also to be considered paralectotypes, 5 of them pinned on the same bricket of elder pith, examined by author in 2022) in the collection of O. Duda ( ZMHB), labelled similarly as those in ZISP but with red labels ‘Typus’ or ‘Paratypus’ (see Fig. 150 View Figs 149–151 ).

Redescription (adapted from RoHÁĆFK 1983). Male (cf. Figs 149, 151 View Figs 149–151 ). Total body length ca 1.3–1.6 mm; general colour brown to pale brown (probably dark brown when alive), with greyish brown microtomentum, subshining on thorax and abdomen, otherwise relatively dull.

Head ( Figs 149, 151 View Figs 149–151 , 155 View Figs 152–157 ) about 1.5× higher than long, brown, paler anteriorly. Frons relatively wide in consequence of strongly reduced eyes ( Fig. 151 View Figs 149–151 ), brown, darker posteriorly, ochreous to yellowish at anterior margin, microtomentose, largely dull; occiput dark brown. Orbits, very narrow interfrontalia and ocellar triangle with pale grey (slightly glittering) microtomentum; frontal triangle similarly but very sparsely microtomentose. Dull brown stripes between orbits and interfrontalia twice wider than those between interfrontalia and frontal triangle, together almost forming dull M-shaped mark ( Fig. 151 View Figs 149–151 ) although less distinct than in other Pteremis species; frontal triangle very narrow and almost reaching anterior margin of frons; the latter narrowly ochreous to dirty yellow. Frontal lunule relatively long and narrow (almost as long as broad), ochreous-yellow, yellowish white microtomentose, hence lighter than anterior margin of frons or face. Face brown ( Fig. 151 View Figs 149–151 ), sparsely whitish grey microtomentose; facial cavities below antennae deeply concave (see Figs 149 View Figs 149–151 , 155 View Figs 152–157 ) and medial carina well developed, both more shining than rest of head. Gena high because of reduced eye ( Fig. 155 View Figs 152–157 ), brown, greyish microtomentose and distinctly separated from occiput by a very narrow shining perpendicular stripe on postgena ( Fig. 149 View Figs 149–151 ). Cephalic chaetotaxy ( Figs 151 View Figs 149–151 , 155 View Figs 152–157 ): macrosetae less robust and shorter than in congeners; pvt small but well developed, strongly convergent to crossed; occe and occi subequal, about half length vti; vti longest of frontal setae; vte shorter than vti, and about as long as posterior ors; oc as long as vte; 2 ors, posterior about as long as oc and about 1.5 times as long as anterior ors; 4 or 5 ifr, all relatively short and weak, two middle pairs usually longer but also slender; 5–9 ads inside and below ors well developed and also setulae on ocellar triangle unusually long; g short weak and almost hidden among a number of (only slightly shorter) setae behind and below it ( Fig. 155 View Figs 152–157 ); vi long (slightly shorter than vti) but not robust, peristomal setulae almost as long as but finer than g and rather numerous (8–10); postocular setulae somewhat shorter than peristomals, in single long row. Eye reduced and flattened ( Figs 149 View Figs 149–151 , 155 View Figs 152–157 ), subcircular to suboval, narrowed posterodorsally ( Fig. 155 View Figs 152–157 ), with longest diameter 1.2 to 1.3 times as long as smallest genal height. Antenna brownish yellow (obviously darker when alive), with 1 st flagellomere usually darker and only a little longer than pedicel, having whitish ciliation on apex slightly longer than cilia on arista. Arista long, about 5.3 times as long as antenna, with short but dense ciliation.

Thorax dark brown to brown, greyish brown microtomentose; mesonotum subshining, pleuron dull. Sutures between pleural sclerites narrowly pale brown to ochreous only in posterior half of pleuron ( Fig. 149 View Figs 149–151 ). Mesopleuron with small and narrow shining spot above fore coxa. Scutellum large and relatively long, rounded subtriangular, slightly convex dorsally. Thoracic chaetotaxy: mesonotal macrosetae relatively weak ( Figs 149, 151 View Figs 149–151 ); 1 hu (almost as long as anterior npl) and 1 enlarged microseta on humeral callus; 2 npl (posterior short, as long as sa); 1 small prs and 1 small sa; 2 pa, the outer long (as long as dc), the inner small and situated rather far from outer pa; only 1 long posterior dc (shorter than laterobasal sc) in prescutellar position, 2 or 3 dc microsetae in front of dc macroseta only slightly enlarged, somewhat longer than ac microsetae); 6–8 rows of ac microsetae on suture but only 4 in front of scutellum; medial prescutellar ac pair not longer than other ac microsetae; 2 very long and robust sc, laterobasal longer than dc or outer pa, apical (by far longest thoracic seta) almost twice longer than laterobasal; 2 stpl, posterior not very long (as long as anterior npl) but also anterior distinct though short (one-third to half length of posterior).

Legs relatively long and slender (particularly tarsi), yellowish brown, trochanters, knees and tarsi often yellow, femora usually darker. Pedal chaetotaxies: f 1 with a row of 4 or 5 posterodorsal setae and with a longer and denser row of 8 or 9 posteroventral setae (those in middle of tibia longest). f 2 anteriorly with a short subapical row of 1 (most distal) longer seta and 2 or 3 short setae. t 2 ventrally (see Fig. 153 View Figs 152–157 ) with only 2 setae, 1 long robust subapical (slightly diverging from axis of tibia) seta considered to be a distally shifted vpa and 1 short anteroventral below middle; thus va seta absent; dorsally ( Fig. 152 View Figs 152–157 ) with chaetotaxy similar to that of other Pteremis species but both posterior setae very small and weak (often hair-like), and also both short setae above distal pair of long setae weak; apex of tibia provided with 3 small subapical setae anteriorly ( Fig. 154 View Figs 152–157 ) and 2 longer posteriorly. t 3 with 1 small but distinct va setula. Other parts of femora and tibiae uniformly finely setulose. Mid basitarsus (mt 2) long and always with 1 short but distinct ventral seta ( Figs 153, 154 View Figs 152–157 ). Hind basitarsus (see Fig. 149 View Figs 149–151 ) relatively slender and more elongate than in all other congeners as are also all other segments of tarsi. Ratio t

2

: mt

2

= 1.53–1.73.

Wing ( Fig. 156 View Figs 152–157 ) peculiar with its whitish membrane ( Fig. 149 View Figs 149–151 ) and yellowish white veins, only C pale yellowish brown. C not extended beyond apex of R

4+5

. Cs

1

with relatively short setulae, though longer than those on rest of C. Cs 2 distinctly longer than Cs 3. R 2+3 relatively long, basally almost straight, apically slightly upcurved to C; R 4+5 sinuate, but distally only slightly upcurved to C and ending closer to apex of wing, than to venal fold of M. Discal cell (dm) relatively long but not narrow and distally slightly tapered, with small process of M and longer one of CuA 1 beyond dm-cu; that of M continued by venal fold almost to wing margin; both outer corners of dm cell slightly obtuse-angled. A 1 moderately long, with only basal part fully developed, more distally represented by colourless fold ending far from wing margin. Anal lobe well developed; alula small and narrow. Wing measurements: length 1.33–1.78 mm, width 0.51–0.70 mm, C-index = 1.48–1.72, r-m\dm-cu: dm-cu = 2.33–3.27. Haltere yellowish, knob slightly darker.

Abdomen brown, sparsely greyish microtomentose, rather weakly sclerotized. Preabdominal terga T2–T5 sparsely (less than sterna) and relatively shortly setose, also setae in posterior corners short and weak. T1+2 largest tergum, with rather characteristic structure and pigmentation (cf. Fig. 162 View Figs 162–164 , same in both sexes). In contrast to female, preabdominal terga (T3–T5) and sterna (S2–S5) not reduced, broad. S5 ( Fig. 157 View Figs 152–157 ) comparatively large, transversely oblong, with rounded corners. It carries a posteromedial, relatively long, comb consisting of a row of blunt spines (those lateral shortened) and a row of small tuberculiform spines in front of it. In contrast to other Pteremis species, there is no pale-pigmented and micropubescent semicircular area in front of posteromedial comb but a group of shorter inclinate setae on each side is present ( Fig. 157 View Figs 152–157 ); setae in posterior two-thirds of lateral parts of S5 well developed, longer and thicker. Disc of S5 (medially, behind anterior margin) with transverse, strongly sclerotized and dark-pigmented stripe.

Genitalia. Epandrium ( Figs 158, 159 View Figs 158–161 ) small compared to other parts of postabdomen, symmetrical, uniformly shortly and densely setulose, particularly around anal fissure ( Fig. 159 View Figs 158–161 ), the latter narrow, elongately suboval, with lateral margins almost parallel. Cerci large, each partly (anterolaterally) separated by an incision from epandrium, far projecting ventrally but distally flattened ( Fig. 158 View Figs 158–161 ) and weakly sclerotized, finely micropubescent, lateroventrally with 1 long and 1 short seta, and ventrally terminated in flat, submembranous appendage, with 2 microsetae on apex ( Fig. 159 View Figs 158–161 ). Cerci medially separated by a deep and very narrow incision, only dorsally, below anal fissure, narrowly fused ( Fig. 159 View Figs 158–161 ). Medandrium low (short) and broad, with usual lateral arms, each connected with posterior part of gonostylus, posteromedially with narrow but short, dark-pigmented keel ( Fig. 159 View Figs 158–161 ). Hypandrium with short and asymmetrical anterior apodeme ( Fig. 158 View Figs 158–161 ) as in other Pteremis species, but its internal arms (connected posteriorly with postgonites) carrying a pair of very slender, long and apically acutely pointed appendages projecting ventrally (visible medially between cerci, see Fig. 159 View Figs 158–161 ). Gonostylus ( Figs 158–160 View Figs 158–161 ) of the same general construction as in other Pteremis species ( Figs 28–30 View Figs 28–32 ), of complex structure, composed of larger (longer) anterior lobe and of smaller (shorter and more medial) posterior lobe. Anterior lobe ( Fig. 160 View Figs 158–161 ) pale-pigmented, flat, with rounded rectangular anterodorsal corner, 3 thicker, slightly curved to sinuate setae anteroventrally plus 1 slender seta close to posterior pair and terminated by 1 ventral, posteriorly directed projection having a pair of small curved spines on apex; posterior part of anterior lobe of gonostylus with oblique longitudinal spinulose ledge (as in other congeners). Posterior lobe of gonostylus more heavily sclerotized and dark-pigmented (cf. Fig. 158 View Figs 158–161 ), projecting ventrally and terminated by robust (somewhat bent medially) spine (see Figs 158, 159 View Figs 158–161 ) apart from 2 fine subapical setae; posterolaterally there is a short process carrying a robust, slightly bent and ventrally (or posteroventrally) directed seta (see Fig. 160 View Figs 158–161 ). Aedeagal complex ( Fig. 161 View Figs 158–161 ) of typically simple construction, surprisingly most similar to that of P. apterina . Phallapodeme simply rod-like, as long as aedeagus, with reduced dorsal keel. Aedeagus with compact, relatively long (as in P. apterina ) phallophore ( Fig. 32 View Figs 28–32 ) having shortly bicuspidate (ventral) apex. Distiphallus largely membranous, weakly sclerotized and pale-pigmented mainly proximoventrally, basally narrow, distally dilated (most in the middle), laterally with an usual pair of slender, pale, band-like sclerites. Middle part of distiphallus with small and slender transverse horseshoe-shaped dorsolateral sclerite (similar to that of P. apterina ); dorsoproximal part of distiphallus finely haired and its dorsal sclerite very slender and pale-pigmented ( Fig. 161 View Figs 158–161 ). Postgonite as long as distiphallus or phallophore, slightly sinuate in lateral view, with proximal third more slender than in all relatives, widest in the middle; distal third slender and relatively straight but ending in terminal knob having a few microsetulae on apex. Ejacapodeme small, with short digitiform process distally (see Fig. 161 View Figs 158–161 ).

Female ( Fig. 149 View Figs 149–151 ). Head, thorax, legs and wings as in male unless mentioned otherwise. Total body length 1.3–2.3 mm. Legs more slender than in male; t 2 with setae longer on the average, and often with an additional small seta above most proximal anterodorsal seta; mid tarsus slightly longer including mt

2

. Ratio t

2

: mt

2

= 1.50–1.67. Wing measurements: length 1.15–1.75 mm, width 0.53–0.81 mm, C-index = 1.40–1.89, r-m\dm-cu: dm-cu = 2.35–3.18.

Abdomen ( Figs 162, 163 View Figs 162–164 ) with preabdominal terga and (less so) sterna reduced and pleural membranous part enlarged, very dilatable during gravidity. T1+2 as large as that of male but T3–T5 markedly shortened and narrowed: T3 as long as but distinctly wider and more transverse than T4 and is the largest and widest tergum; T5 longer but narrower than T4 ( Fig. 162 View Figs 162–164 ), all very shortly and sparsely setose. Preabdominal sterna narrower but S3 and S4 longer than adjacent terga. S2 (or S1+2) unusually larger than S5 but slightly transverse (narrower anteriorly); S3 larger than other sterna ( Fig. 163 View Figs 162–164 ), roughly transversely hexagonal; S4 transversely suboblong, slightly larger than (darker) S5; S2–S5 with long, dense fine setae.

Postabdomen ( Figs 165–167 View Figs 165–167 ) narrow and telescopically retractile into preabdomen (cf. Fig. 162 View Figs 162–164 ). T6 narrower but darker than T5, simply suboblong ( Fig. 165 View Figs 165–167 ), with short setae in posterior half; T7 as wide as but yet longer than T6, distinctive by its posterior, almost membranous part being anteromedially deeply extended into anterior darker and shortly setulose part; medially, in submembranous part, there is a pair of robust short setae ( Fig. 165 View Figs 165–167 ). T8 dorsally with tripartite pigmentation composed of pale brown medial spot and dark-pigmented lateral parts ( Fig. 165 View Figs 165–167 ) being shortly setose posterodorsally, and bare, with broadly pale ventral margin (see Figs 166, 167 View Figs 165–167 ). T10 relatively broad, transversely rounded pentagonal, medially pale-pigmented and carrying 2 pairs of short setae ( Fig. 165 View Figs 165–167 ). S6 slightly narrower and longer than T6, with rounded anterior corners and shortly setulose in posterior half. S7 narrower than S6, somewhat tapered anteriorly, with subcordate darker pigmentation, thus posteromedially with pale-pigmented rounded triangular area; dark part of T7 with very short setulae. S8 ( Fig. 167 View Figs 165–167 ) small, of peculiar form, besides main anterior pale-pigmented but bare plate with dark medial stripe, there is a very small, posterior, transverse, frame-shaped structure carrying 4 setulae posteriorly; an additional pair of small setulae arise on connective membrane between these structures. S10 also distinctive: its lateral parts convex, dark, heavily sclerotized and shortly setulose; its pale medial part bears an unusual, ventrally projecting, fillet-like structure resembling a very narrow U in ventral view ( Fig. 167 View Figs 165–167 ). Spectacles-shaped sclerite not observed. Spermathecae ( Fig. 164 View Figs 162–164 ) blackish, pear-shaped, with elongate, strongly curved and sclerotized distal parts of ducts; proximal part of spermathecal bodies with several small tubercles and thornlets. Cerci ( Figs 165, 166 View Figs 165–167 ) small, subconical, micropubescent, each with several short, hair-like, slightly sinuate or curved setae, apical longest. Comments. DUDA (1938) placed this unusual species in its own subgenus Paraspelobia and discussed its affinity (on the basis of some external characters) to Spelobia Spuler, 1924 and Chaetopodella Duda, 1920 , both clearly unrelated groups of Limosininae . HACKMAN (1969) placed it near Chaetopodella . RoHÁĆFK (1983), based on examination of the male and female terminalia, recognized its affinity to Pteremis species but retained it in the redescribed genus Paraspelobia because of several distinct differences.

For the reasons given in the introduction, but mainly because of clearly identical construction of the male genitalia, the species is now considered a member (albeit most aberrant) of the genus Pteremis and a sister group to the rest of the genus. Pteremis species other than P. vlasovi share the following putative synapomorphies: mid basitarsus with ventral seta reduced or absent; male S5 with membranous area in front of posteromedial comb of spines; ventral projection of anterior lobe of gonostylus projecting posteriorly, posterior lobe of gonostylus with setae adjacent to terminal spine long and strong; female S8 with posteromedial group of setae on elevated sockets; paired spermathecae with sclerotized parts of ducts fused behind its common proximal end.

Externally, P. vlasovi can easily be recognized by the reduced eyes and high gena ( Fig. 155 View Figs 152–157 ), t 2 with vpa seta shifted distally and so resembling va seta ( Fig. 153 View Figs 152–157 ), mt 2 with distinct basitarsal seta ( Fig. 154 View Figs 152–157 ), wing with milky white membrane and C not extended beyond apex of R 4+5 ( Fig. 156 View Figs 152–157 ). Further, its epandrium is very shortly setose ( Fig. 159 View Figs 158–161 ), female T7 ( Fig. 165 View Figs 165–167 ) and S7 ( Fig. 167 View Figs 165–167 ) are modified, female S8 and S10 ( Fig. 167 View Figs 165–167 ) carry peculiar structures, female T10 has 2 pairs of small setae, cerci are small ( Fig. 165 View Figs 165–167 ) and spermathecae ( Fig. 164 View Figs 162–164 ) have distal sclerotized parts of ducts strongly curved.

Biology. Judging from label data of type specimens and also the adult morphology (reduced eyes, prolonged legs, partly desclerotized abdomen) the species is microcavernicolous, inhabiting burrows and nests of small rodents, viz. the long-clawed ground squirrel Spermophilopsis leptodactylus (Lichtenstein, 1823) (for its current classification see KRYšTUrFK et al. 2016) and (less frequently) also the great gerbil Rhombomys opimus (Lichtenstein, 1823) in sandy desert habitats, see also RoHÁĆFK (1983). Adults were recorded in II–V and VIII ( DUDA 1938, Ro- HÁĆFK 1983, type material examined) but surely occur in burrows also in other months of year as is usual for strictly subterranean species of Limosininae .

Distribution. Turkmenistan; the species is hitherto only known from (the long) type series from the vicinity of Ashkhabad, the capital of the country.

Key to West Palearctic species of Pteremis View in CoL , including