Zealantha fasciolata, Roháček, 2021

Roháček, Jindřich, 2021, New species and records of Anthomyzidae (Diptera) from the East Palaearctic, with a checklist of taxa occurring in the area, Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 61 (1), pp. 261-288 : 281-286

Zealantha fasciolata sp. nov.

( Figs 56–69 )

Type material. Hඈඅඈඍඒඉൾ: ♀, labelled:‘Toyotomi, HOKKAIDO, 29.VI. 1967, T. SAIGUSA’ (Indian ink handwriting) and ‘ Holotypus ♀, Zealantha fasciolata sp. n., J. Roháček det. 2020’ (red label) ( SIINH, genit. prep.).

Description. Male unknown.

Female. Total body length 2.94 mm. Body distinctly bicolourous ( Figs 57–61 ), head and thorax dorsally pale brown and ventrally yellow, with light-grey microtomentum, while abdomen and extremities are yellow-and-brown (or pale brown) variegated. Head ( Figs 57, 59, 60 ) about as long as high, anteriorly (in profile) almost rectangular, with frons somewhat projecting in front of eye, pale brown and yellow. Occiput dorsomedially strongly concave (as in Zealantha thorpei Roháček, 2007 ), brown medially and ochreous yellow laterally, with a distinctive crescent-shaped patch of silvery-white microtomentum above foramen (a pair of stripe-like patches in Z. thorpei ). Frons relatively narrow (as in Amygdalops species ), largely pale brown ( Fig. 60 ) but orbital plates and anterior part of frons dirty yellow to orange yellow, and ocellar triangle dark brown, all dull due to dense greyish microtomentum. Orbital plate mostly yellow, brownish only at base of vte, all sparsely whitish microtomentose. Frontal triangle narrow, somewhat longer than broad, distinctly delimited because depressed (see Fig. 57 ) and reaching to anterior two-fifths of frons; band-like areas between orbital plates and frontal triangle brown striated (as in Z. thorpei ) and reaching anterior margin of frons ( Fig. 57 ). Ocellar triangle flat, dark brown but with silvery bluish-grey microtomentum; ocelli relatively large ( Fig. 60 ). Frontal lunule very small and narrow, depressed but visible, light yellow. Face relatively narrow, medially weakly sclerotized and somewhat depressed, pale brown but whitish microtomentose; parafacialia and gena yellowish-white and silvery-white microtomentose, both narrowly ochreous margined but on gena this stripe anteroventrally widened to form a distinctive brown elongate spot below vi and subvibrissa (see Fig. 59 ); postgena pale yellow ventrally to pale brown dorsally, silvery-white microtomentose. Mouthparts small, yellow, with clypeus and palpi yellowish white. Cephalic chaetotaxy ( Figs 57, 59, 60 ): pvt relatively small but with apices crossed; vti slightly shorter than vte, the latter and posterior ors longest of cephalic setae; oc as long as vti and arising outside of ocellar triangle (as in Z. thorpei ); 3 ors, posterior as long as vte, middle somewhat shorter, anterior short and thin (about half length of, and arising close to middle ors) and somewhat inclinate; no microsetula in front of anterior ors; only 1 pair of minute medial microsetulae just at anterior margin of frons; 1 inclinate setula behind vte; postocular setulae (9–11) short, in single dense row; postgena with a few setulae and 1 relatively short posteroventral seta; 1 vi (slightly shorter than middle ors); subvibrissa well developed, as long as vi but thinner; 5 or 6 short and fine peristomal setulae. Palpus slender, yellow, with 1 ventral preapical seta and 3 or 4 small ventral setulae in proximal half. Eye convex, relatively large, elongately elliptical ( Fig. 59 ), with longest diameter oblique and about 1.5 times as long as the shortest. Eye lacking pilosity ( Figs 57, 59 ) in contrast to that of Z. thorpei . Gena short, shortest height about 0.11 times shortest eye diameter. Postgena with posteroventral corner almost right angled ( Fig. 59 ). Antenna strongly geniculate, entirely ochreous yellow; scape minute; pedicel short, simple, not cap-like overlapping base of 1st flagellomere, with a number of short dark setulae at distal margin and 1 anterodorsal seta as long as anterior ors; 1st flagellomere strongly flattened laterally, with white pilosity on anteroventral margin longer than dark cilia on arista. Arista brown with pale brown basal segment, about 1.8 times as long as antenna, relatively shortly ciliate.

Thorax slightly narrower than head, ochreous to pale yellow with brownish longitudinal vittae, light-grey microtomentose, subshining to dull. Mesonotum ochreous yellow, with 3 brownish longitudinal vittae: 1 narrow unpaired medial (running from anterior margin to scutellum where widened) and 2 broad (from dc line to sa line) laterals (cf. Figs 57, 58 ); humeral and notopleural areas yellow; scutellum largely brownish on disc but ochreous yellow laterally. Pleuron yellow to (ventrally) whitish yellow but dorsally with distinctive brown band extending from cervix to base of abdomen and posteriorly also widened on postscutellum and metanotum. Thoracic chaetotaxy: 1 hu (longer than posterior npl); 2 npl (anterior distinctly longer than hu); 0 prs and 0 sa (both reduced to microsetae); 1 pa (as long as hu); 2 postsutural dc, anterior short and weak (less than half length of posterior), posterior long and strong (almost as long as apical sc); 6 or 7 dc microsetae, 1 in front of anterior dc enlarged (on left side of holotype twice as long as others); 4 rows of ac microsetae on suture but only 2 rows behind anterior dc, the latter reaching behind level of posterior dc; 2 sc, laterobasal very weak and only as long as hindmost ac microseta, apical sc long (longest thoracic seta) and robust, slightly longer than posterior dc; 1 minute ppl, reduced to microseta in contrast to that of Z. thorpei ; 2 relatively long and strong stpl (anterior shorter and thinner) and 2 pale microsetae in dorsal half of sternopleuron; its ventral part with 4 longer pale setae. Scutellum rounded triangular, about 1.5 times as wide as long, flat dorsally; postscutellum well developed, distinctly bulging. Legs dirty yellow; all femora with darker (pale brown) subapical annulus and whitish knee (see Figs 32–34 ); tibiae variably variously coloured, t 1 with some darkening proximally but with base whitish ( Fig. 32 ), t 2 uniformly yellow, t 3 almost entirely darkened (except for whitish base); tarsi entirely yellow or pale yellow, including last tarsal segment. f 1 ( Fig. 32 ) with ctenidial spine entirely absent, thus with only long thin setae in posteroventral (1 seta longer) and posterodorsal (2 setae longer) rows; f 2 and f 3 uniformly setulose ( Figs 33, 34 ); t 2 with short (about as long as maximum width of tibia) ventroapical seta ( Fig. 33 ); t 1, t 3 ( Figs 32, 34 ) and all tarsi simply setulose, only fore basitarsus with 2 proximoventral setulae somewhat prolonged but fine ( Fig. 32 ). Wing ( Fig. 56 ) moderately long, not very narrow, with pale ochreous-brown veins and membrane, the latter hyaline. C with very small and sparse spinulae between apices of R 1 and R 2+3 (not visible in Fig. 56 because situated on other side of wing), as in Z. thorpei . Sc well developed basally and fused with R 1 apically to form a small preapical kink at level of subcostal break. R 2+3 long, distinctly sinuous distally, running parallel to C but subapically somewhat diverging and with apex upcurved; the cell r 1 narrow, only half the width of cell r 2+3; R 4+5 slightly bent along its entire length, subparallel to M distally. M (beyond dm-cu) almost straight. Cell dm relatively small and distally narrow ( Fig. 56 ), with r-m situated at about basal third. Apical portion of CuA 1 long, about 3.3 times as long as dm-cu, slightly downcurved, not reaching wing margin; A 1 short, ending far from it. Alula small, narrow. Wing measurements: length 2.82 mm, width 0.93 mm, Cs 3: Cs 4 = 1.42, r-m\dm-cu: dm-cu = 3.63. Haltere pale ochreous-yellow.

Abdomen relatively slender, elongate, largely pale ochreous-yellow but with terga (T2–T6) with distinctive transverse brown bands covering posterior half of each sclerite (see Fig. 61 ) but very posteriorly yellowish-white margined (in Z. thorpei these terga only posterolaterally dark spotted). T1 with brown subtriangular spot in posterolateral corner (as in Z. thorpei ). T1 and T2 dorsally separate, the former with very short and sparse setulae, mainly laterally. T2 slightly shorter than T3; T3–T5 subequal in length, broad, bent onto lateral sides of abdomen, all with sparse, short but relatively robust setae (longest at posterior margin); T5 ( Fig. 63 ) narrower than T4 and distinctly tapered posteriorly. Preabdominal sterna paler than terga, yellowish white, relatively large and all, except for S1, finely setose. S1 short, much shorter than wide, and bare. S2–S4 of similar size and each somewhat wider than long, with corners rounded; S2 and S3 wider anteriorly than posteriorly; S4 slightly transversely suboblong; S5 (on the contrary) wider posteriorly than anteriorly ( Fig. 65 ). Spiracles situated in pleural membrane near ventral margin of terga.

Postabdomen ( Figs 63–65 ) relatively short, tapered posteriorly. T6 large and broad (but much narrower than T5, see Fig. 63 ), transversely subtrapezoid, thus tapered posteriorly, pale yellow, with brown transverse band covering posterior half except for pale posterior margin (thus similarly coloured as preceding terga), short-setose on dark part of tergum, with setae at posterior margin longer. S6 relatively large, of similar size and shape to that of S5 (see Fig. 65 ), thus slightly wider than long, subtrapezoidal (wider posteriorly) but with sides rounded (convex), shortly setose in posterior half, with longer setae at posterior margin only. T7 and S7 separate (in contrast to those of Z. thorpei ). T7 much narrower than T6 but bent farther onto lateroventral sides of postabdomen ( Fig. 64 ), slightly tapered posteriorly, dark brown in posterior two-thirds, whitish yellow anteriorly ( Fig. 63 ), with short thicker setae on dark part, and with 7th spiracle embedded in pale anterolateral corner (cf. Fig. 64 ). S7 comparatively large and broad ( Fig. 65 ), almost square-shaped, pale pigmented, finely short-setose in posterior two-fifths. T8 relatively broad (slightly narrower than T7) plate-shaped, transversely suboblong with rounded corners ( Fig. 63 ), flat, pale pigmented and microtomentose, with a few fine setae at posterior margin, including 1 or 2 longer in posterolateral corner. S8 ( Fig. 65 ) only slightly shorter but narrower than T8, transversely trapezoidal but posteromedially somewhat prominent ( Fig. 68 ) and with narrow fissure (better visible in caudal view), densely micropubescent and finely setose. Genital chamber (uterus) relatively narrow, with internal sclerotization ( Figs 68, 69 ) composed of a pair of posterior, flat, crooked, pale-pigmented sclerites and 1 anterior annular sclerite, the latter ribbon-shaped, strongly (fronto-caudally) compressed and bent onto lateral surfaces of genital chamber (somewhat resembling that of A. aspina sp. nov.). Ventral receptacle ( Fig. 67 ) formed by broad, relatively short and membranous tube-like proximal duct and distinctly sclerotized, shortly subconical distal part gradually projecting into curved digitiform process. Remnant of accessory gland ( Fig. 69 ) hyaline, small, and connected to short, very slightly (in the middle) dilated and indistinctly ringed duct. Spermathecae (1+1) subovoid to shortly pyriform ( Figs 62, 66 , 68 ), each with plain surface and long slender slightly bent sclerotized cervix (half to two-thirds length of spermathecal body) (similar to that of Z. thorpei ); spermathecal duct ( Fig. 68 ) relatively short (only as long as genital chamber) and broad, terminally twice wider than cervix. T10 ( Fig. 63 ) small, transversely suboblong, with rounder posterior corners, pale, with 1 pair of long setae at posterior margin surrounded by some micropubescence. S10 ( Figs 65 , 68 ) larger than T10, wider than long, transversely pentagonal, micropubescent in posterior two-thirds and with some fine setulae at posterior margin. Cercus ( Figs 63–65 ) very short, broad, with relatively short setosity, including some thicker setae, dorsopreapical seta somewhat longer than others.

Discussion. This peculiar (even in the female sex) species differs distinctly from all described Anthomyzidae both in external appearance and internal structures. Although its head and body are somewhat reminiscent of an Anthomyza species , the structures of the female postabdomen and construction of the internal genitalia prevent its distinct affiliation with any of the described genera. Because some of its distinctly apomorphic characters are shared with Zealantha thorpei Roháček, 2007 (type and only species of the genus), the new species is tentatively placed in Zealantha . The relationship of Z. thorpei and Z. fasciolata sp. nov. is mainly supported by shared characters of the female post- abdomen, viz. the broad and flat T8 ( Fig. 63 ), compact S8 with only a small posteromedial incision ( Fig. 68 ), ventral receptacle composed of a relatively short broad duct and short distal sclerotized part terminating in a curved digitiform apical process ( Fig. 67 ) and, particularly, strikingly similar spermathecae with a plain surface and a very long sclerotized cervix ( Fig. 62 ), the latter two features considered apomorphies of the genus Zealantha (see RඈIJගඹൾκ 2007). There are also some other shared external features treated as apomorphies of Zealantha , e.g. oc arising outside the ocellar triangle. A relationship between these two species can also be supported by a silvery microtomentose spot on the strongly concave occiput (solid in Z. fasciolata but divided into 2 stripes in Z. thorpei ), a flat ocellar triangle with large ocelli, a similar cephalic chaetotaxy (but with pvt short in Z. fasciolata ), reduced prs and sa (which have entirely vanished in Z. fasciolata ), variegated abdominal terga (dark-banded in Z. fasciolata , dark spotted in posterior corners in Z. thorpei ), the similarly shaped although differently micropubescent T10 and S10 and the short female cercus. However, it cannot be denied that there are also characters markedly different in both these taxa, which prevent unequivocal classification of Z. fasciolata within Zealantha . These particularly include the absence of autapomorphies considered unique for Zealantha , viz. eye densely long-pilose, head and thorax with peculiar velvety dark bluish-grey microtomentum, and also the following: pvt unusually long, ppl long, female T7 and S7 fused to form a tergosternal ring (but with S7 indicated by posterior incisions, see RඈIJගඹൾκ 2007: fig. 18) and female S10 almost bare (RඈIJගඹൾκ 2007). Moreover, the annular sclerite in the female genital chamber is quite dissimilar being elongately ovoid in Z. thorpei while compressed in Z. fasciolata . For all the above reasons, the new species is only provisionally described as a Zealantha pending discovery of males (and knowledge of male genital characters) for clarification of its generic affiliation.Therefore, it is suggested that the generic diagnosis of Zealantha is not modified for the time being. Zealantha fasciolata can be easily distinguished from all known Anthomyzidae by a combination of the following external characters: head with elongately ovoid eyes, long subvibrissa, thorax with darker longitudinal vittae, prs and sa setae absent, f 1 without ctenidial spine, wing with cell dm narrow and apical portion of CuA 1 long, and, particularly, abdomen with dark transversely banded terga. The latter colouration of the abdomen occurs infrequently in the Anthomyzidae , known e.g. in the Nearctic Anthomyza dichroa Roháček & Barber, 2016 and its relatives (see RඈIJගඹൾκ & Bൺඋൻൾඋ 2016) but hitherto not recorded in the Palaearctic species ofAnthomyzidae. Of course, the female postabdominal characters (see above) of Z. fasciolata are also highly species-specific.

Etymology. The species is named using the Latin adjective fasciolatus (-a, -um) meaning belted, for its dark transverse bands on the abdominal terga.

Biology. Unknown. The holotype female was encountered in June.

Distribution. Japan: Hokkaido.

Figures

Figs 56–61. Zealantha fasciolata sp. nov., female holotype. 56 – left wing, length 2.82 mm; 57 – head and thorax, anterodorsally; 58 – female after dissection, laterally (wing length 2.82 mm); 59 – head and thorax, laterally; 60 – head, frontally; 61 – abdomen, dorsally (photographed relaxed in glycerine). Photos by J. Roháček.

Figs 62–66. Zealantha fasciolata sp. nov., female holotype. 62 – spermatheca; 63 – postabdomen + 5th abdominal segment, dorsally; 64 – the same, laterally; 65 – the same, ventrally; 66 – spermatheca. Scales = 0.05 mm (Figs 62, 66) and 0.2 mm (Figs 63–65). For abbreviations see p. 263.

Figs 67–69. Zealantha fasciolata sp. nov., female holotype. 67 – ventral receptacle, laterally; 68 – genital chamber with S8, S10 and spermathecae, ventrally; 69 – the same, without spermathecae, laterally (setosity on T8 and S8 omitted). Scales = 0.05 mm (Fig. 67) and 0.1 mm (Figs 68, 69). For abbreviations see p. 263.

Figs 29–35. Legs and their parts of Anthomyzidae. 29–31 – Anthomyza breviclavus sp. nov., female holotype: 29 – left f1, t1 and fore basitarsus posteriorly (chaetotaxy partly reconstructed); 30 – distal end of right t2 and mid basitarsus, anteriorly; 31 – apex of left t3 and hind basitarsus, anteriorly; 32–34 – Zealantha fasciolata sp. nov., female holotype: 32 – left f1, t1 and fore basitarsus, posteriorly; 33 – left f2 and t2, anteriorly; 34 – right f3 and t3 posteriorly; 35 – Fungomyza cercata Roháček, left f3, t3 and hind basitarsus, anteriorly. All scales = 0.5 mm. For abbreviations see see p. 263.