Paratendipes sinespina, Cranston, 2020

Cranston, Peter S., 2020, Life histories of Paucispinigera Freeman, Paraborniella Freeman and Paratendipes Kieffer (Diptera: Chironomidae) with phylogenetic considerations, Zootaxa 4853 (4), pp. 527-547 : 540-545

Paratendipes sinespina sp. n.

( Figs 8–10 )

urn:lsid:zoobank.org:act:0908E66F-415D-4307-8FF1-A249D687D94C

Paratendipes ‘K1’ Cranston 1991, 1996.

Material examined. Holotype, here designated: Le/Pe/ ♂, AUSTRALIA, Northern Territory, Kakadu N.P., Radon Springs [headwater Gulungul Ck.], 12°45’S 132°55’E, 13/ 14.iv.1989 (Cranston)(ANIC).

Paratypes (collected Cranston , deposited ANIC, unless otherwise stated). 4♂, as holotype; P ♂, Magela Ck, 12°35’S 132°52’E, iv–v.1992 (Hardwick); ♂, Magela Ck, Ranger outfall, 12°41’S 132°55’E, 20.v.1988 (Wells & Suter) ; 4♂, 14Pe, P/ ♂, 9P/ ♀, ‘Treehouse’, Magela Ck, below Bowerbird Billabong, 12°47’S 133°03’E, 28.v.1988 (3 BMNH, 3 ZSM); Pe , Hickey Ck, 12°55’S 132°50’E, 29.v.1988 ; Le / Pe / ♀, Wildman R. @ Arnhem Hwy X., 12°50’S 132°01’E, 2.vi.1988 ; Pe , Barramundie Ck, below falls, 13°22’S 132°28’E, 28.v.1988 ; 6 Pe, P ♂, P ♀, 13°30’S 132°30’E, Rockhole Mine Ck , RMC site A, 25.iv.1992 (Hardwick) ; Pe , Koolpin Ck, 13°29’S 132°35’E, 25.v.1988 , Pe , same except 15/16.1992; Pe, S. Alligator R., Fisher Ck, 13°33’S 132°33’E, 24.v.1988 ; 5♂, Pe, Le / Pe / ♂, 13°34’S 132°35’E, S. Alligator R., Gimbat spillway, Coronation Hill, 13°34’S 32°35’E, 19/ 20.iv.1989 .

Other material. Queensland: Pe, U. Brisbane R., 26°48’S 152°16’E, 20.ix.1989 .

Western Australia: ♂, Kimberley, Vynnot Ck , 16°31’S 125°16’E, 17–20.vi.1998 (Weir) .

Etymology. sine spina (‘without’ ‘spine’ L.), refers to the simple anterior tibial apex lacking the fine spine that characterises nearly all Paratendipes .

Description. Male (n=10). Body length 4.0– 4.4 mm, wing length 2.0– 2.3 mm. Wing hyaline with weak pattern as in Fig. 8A , when on slide, seen best under semi-dark field. Pale brown with darker vittae. Legs with faint pattern of dark femora and ‘knee’, tibiae pale until apex, and darker on distal tarsomeres (as with wing, best seen under dark field).

Antenna. With 13 flagellomeres; Fl 1-12, 380–410, Fl 13 340–370. A.R. 0.9–1.1

Head. Eye bare, with dorsomedial parallel-sided extension 5–6 ommatidia long, separated medially by c. 10 ommatidia. Temporals 5–10 uniserial; clypeals 8–12. Frontal tubercles absent. Palp 5-segmented, segment 2 globular, segments 3, 4 and 5 quite similar in length, variably contracted; segment 3 lacks sensilla.

Thorax ( Fig. 8C ). Antepronotal lobes taper dorsally, medially slightly divided at notch, without lateral antepronotal setae. Scutum, smoothly curved in profile without tubercle, not overreaching antepronotum. Ac c. 6 –14 uni-biserial starting from front, ending mid-thorax; 8–15 uniserial Dc each arising from pale spot; Pa 3; Scts 5–9 uniserial or if>6, with 2 in more posterior position.

Wing ( Fig. 8A ). Membrane with neither setae nor microtrichia. Consistently patterned with faint pale brown clouds in mid cell r 4+5, mid and subapical in m 1+2, mid m 3+4, distal cu and bordering An vein. Anal lobe shallow. Costa ends at apex of R 4+5 just proximal to wing apex. R 2+3 distinct, ending midway between apices of R 1 and R 4+5’ FCu distal to RM, VR 1.2–1.3. Anal vein distinct with associated darkening. Brachiolum with 2 setae. R setose (9–11), R 1, R 4+5 bare. Squama bare.

Leg. Apex of fore tibia with rounded scale, without spur ( Fig. 8D ). Mid and hind tibiae apically with two slightly separated combs, combined occupying about 60% circumference, each comb with short straight spur ( Fig. 8E ). Leg ratios: LR 1 1.14–1.31, BV 1 1.74–1.82, SV 1 1.62–1.82; LR 2 0.52–0.58, BV 2 3.4–3.7, SV 2 3.5–4.1; LR 3 0.63–0.68, BV 3 2.7–2.8, SV 3 2.8–3.1. Pulvilli absent, empodium small.

Abdomen. Tergites I–VII with sparse irregular setae.

Hypopygium ( Fig. 8 H–K). Anal tergite with bands delineating 6-8 median anal tergal setae, band petering out prior to base of anal point, microtrichiose to near anal point origin, tergite IX with submarginal short and longer setae. Gonocoxite 60–65 long; gonostylus 70–75 with straight inner margin tapering to rounded apex, strongly microtrichiose and conventionally setose. Anal point relatively short (30–32), bare, near parallel-sided to slightly broadened in mid-section, with rounded apex. Superior volsella 50–52 long ( Fig. 8 H–J), swollen digitiform with downcurved (ventrally-directed) apex, on dorsal surface with 3 linear aligned setae close to base, without more distal setae; ventrally with setose lobe without microtrichia. Median volsella 35–38 long with short stem (10–12), distally with> 10 taeniate setae tightly clustered, curving to terminate posteriorly-directed ( Fig. 8K ). Inferior volsella 50–55 long, free from gonocoxite from base, microtrichiose and with long simple setae mostly orientated antero-medially, lacking distinct apical seta. Transverse sternapodeme dark, square-arch shaped, phallapodeme narrow.

Female (n=2) (teneral, some partially dissected from pupa, allowing limited description).

As male, except: Antenna: 55–78, 40–55, 50–75, 40–55, 82–101; A.R. 0.38–0.40. Temporals 15-17, clypeals 15–18. Palpomeres: 50,134,140,170. Thorax ( Fig. 8B ) more setose than male; Ac 10–12, Dc 18–19 with 4–5 in humeral area, each arising from small pale spot; Pa 3; Scts 13–16. Wing crumpled, teneral, seemingly as in illustrated male, with pigmentation no stronger; setation: R 15–16, R 1 8–12 and R 4+5 18–20. Legs (n=1): LR 1 0.60, BV 1 1.85, SV 1 1.88; LR 2 0.51, BV 2 2.26, SV 2 4.14; LR 3 0.59, BV 3 2.8, SV 3 3.2. Pulvilli absent, empodium weak.

Genitalia as in Saether (1977). Ovoid seminal capsules (110–140 x 75–100) are located more caudal in abdomen with relatively straight seminal ducts abruptly narrowed and connecting immediately prior to common opening. GpVIII comprises only modest dorsomesal lobe. Cerci squat, 75 x 75-80.

Pupa. Medium-sized, ca 4.5–5.5 mm long. Thorax and cephalic area golden brown, abdomen pale hyaline with little indication of darker apophyses; comb and anal lobe golden-brown.

Cephalothorax. Frontal apotome smooth without cephalic tubercles or frontal warts; frontal setae (55–60 μm) arising direct from frons ( Fig. 9A ). Thoracic horn with apically bluntly-spinose, basal branch (c. 120 μm long) ( Fig. 9B ), divided into 5–6 intertwined hyaline branches; basal ring small, oval and with small tracheal ‘bundle ‘. Anterior thorax and median suture rugulose with small tubercular scales, strongest at mid-scutum. Prealar tubercle absent. Antepronotum with 1 median, 1 lateral setae; 2 precorneals; dorsocentrals (Dc) each c. 25–35 μm long with Dc1 and Dc 2, near contiguous to each other and well separated (200 μm) from the also near adjoining paired Dc 3 and Dc 4.

Abdomen ( Fig. 9C ). Tergite I bare, II–VI each with extensive subquadrate spinule patch, not differentiated into transverse bands of stronger anterior or posterior spinules; pleurae bare except for small posterolateral area of fine spinules on V. Tergites VII–VIII with small patches anterolateral spinules, anal segment bare. Tergite II hook row continuous, comprising 20–25 hooks, 35–46% width of segment II. Narrow transverse bands of spinules on conjunctives of III and IV. Vortex only on IV. Only sternal armament a small patch of fine spinules of max. length 6 μm, near base of L 4 on V. Pedes spurii B strongly developed only on segment II. Posterolateral corner of segment VIII (‘comb’) with golden-brown teeth, posteriormost tooth dominant, with 2–3 shorter, curved pointed teeth (Fig, 9D). Apophyses weak / indistinct. Segment I with 3D, 1V and 1L setae; II with 4D, 3V and 3L; III with 5D, 4V and 3L; IV with 5D, 4V and 3L setae of which L 1 and L 3 taeniate (LS), V with 5D, 4V and 3LS, VI, VII with 5D, 4V, 4LS unevenly spaced, L 1 & 2 well separated from approximated posteriorly located LS 3 & 4. VIII with 1D, 1V and 4LS evenly spaced in posterior 2/3 segment. ‘O’ setae very fine, definitely on TII–VIII, uncertain / absent on sternites. Anal lobe elongates semicircular with uniseriate fringe of 19-30 long taeniae, with fine, slender 25–30 long, dorsal seta. Genital sac of male extends beyond anal lobes, female shorter.

Larva (n=2). As generic diagnoses with specific and mensural characters as follows: Body colour, length and morphology unknown (only exuviae); head length 500μm, postmentum length 180. Head capsule pale yellow with darker yellow to brown teeth of the dorsomentum, inner mandible and premandible. Genae / postmentum pale; occipital margin narrow, darker yellow-brown than postmentum.

Antenna ( Figs 9E , 10A ). 6-segmented, lengths 52–55, 20–24, 12–15, 7–8, 4–5, 3–4; A.R. 1.2-1.3. Lauterborn organs well developed on pedestal in mid-2nd and sessile on apex of 3rd segment. Style subapical on 3rd segment. Blade 56, extending slightly beyond antennal apex.

Labrum ( Figs 9F , 10D ). SI and SII setae plumose, SI on common base, not fused. Labral lamellae c. 20 evensized spines on single plate. Pecten epipharyngis 3 simple lobes. Chaetulae of ungula short, squat, not differentiated into laterales and basales. Premandible with 2 teeth, beard of stubbly spinules.

Mandible ( Figs 9G , 10E ) 70–90, with pale dorsal tooth, larger darker triangular apical tooth and 2 darker inner teeth; darkened distal mola rounded. Seta subdentalis 12, slender, short.

Mentum ( Figs 9H , 10B, C ). Ventromentum delimited, comprising 8 teeth; pale median 4 subequal teeth flanked by 2 darker teeth, the inner smaller than next lateral tooth; 4 darker dorsomental teeth each diminishing slightly in size laterad. Ventromental plate fan-shaped with micro-crenulate anterior margin, internally with 5–6 broad coarse striae restricted to the lateral 3/4 of plate, each terminating anteriorly in a prominent triangular spine, associated with one crenulation of the plate margin.

Abdomen (n=1, exuviae), with small pale (almost hyaline) simple parapod claws. Body setae 24–30 long, simple. Procercus minute, squat, 5 high x 10 wide, bearing 6 apical setae of length 300–350; 2 procercal setae displaced to cuticle a short distance from procercus, 110–130 long. Posterior parapod c. 350–400 long, with anal seta 110–130 long.

Comments. The associated larva and pupa of Paratendipes sinespina conform substantially to the Holarctic diagnoses of Pinder & Reiss (1983, larva, 1986, pupa) including after expansion by recognition of the life stages of Paratendipes basidens Townes ( Epler & Ferrington 1994) and Paratendipes nubilus Meigen ( Biro & Klink 2005) as incorporated into Epler et al. (2013) for larvae. The flat foretibial apex lacking any spine in both sexes of P. sinespina appears significant. Never-the-less, Paratendipes inarmatus Freeman from Batu Caves, Malaysia, also has a simple apex on the foretibia, and here Freeman’s (1962) comments are relevant “Even though the presence of this spur is an important character of the genus, inarmatus resembles other species so closely in hypopygial and thoracic structure that I have not thought it wise to place it in a new genus. The African P. seydeli Freeman [1957] also lacks this spur, but that is not such an otherwise typical species as inarmatus ” ( Freeman 1962: p.131). With the allocation of P. seydeli to the recently described Paraskusella Cranston (2018), we can see that Freeman also surely was correct about P. inarmatus .

The immature stages and male genitalia locate P. sinespina within Paratendipes , as with Malaysian P. inarmatus Freeman , albeit both as slightly atypical species. Essentially the expansion needed for the generic diagnosis is inclusion of the flat apex on the foretibia without a spine in both sexes of the adult, and the unusual distribution of taeniate L setae on abdominal segments IV and V, seen otherwise only in modified form in P. subaequalis and an unidentified species from Singapore.

For reasons given above, the Australian species is treated as an endemic and new to science. However, northern Australian tropical species of several Chironomini are distributed also in Asia and extra-limital taxa need consideration. Excepting the plain winged P. inarmatus , none elsewhere are reported to lack the fore-tibial spine. Disregarding this, amongst species with bare squama and tapering anal point (the nudisquama group), the wing patterning resembles two others, namely the Asian P. nigrofasciatus Kieffer 1916 ( Yamamoto & Yamamoto 2012) and P. nubilipennis Freeman 1957 from Africa and Saudi Arabia (Cranston 1989). Neither species agrees exactly with the leg and/ or wing pattern of P. sinespina although pigmentation is weak and the pattern must be determined on a microscope slide with slightly ‘out of phase’ optics, or ‘pseudo-dark’ field. Pale pigmentation may be consequence of rapid development in warm tropical waters as seen in other tropical taxa such as Polypedilum johannseni Sublette & Sublette ( Tang & Cranston 2019) . The median volsella of P. sinespina differs from all illustrated male genitalia of Paratendipes , being ‘bushier’ with dense taeniae significantly overlapping with those opposite then curved to orientate and terminate more distally. The superior volsella with a ventral setose lobe also may differ, but existing illustrations are inconsistent regarding this feature. The distribution of taeniate lateral setae on the pupa of P. sinespina sp. n. might be unique in the genus but this cannot be verified due to the paucity of published evidence from rearings, especially lacking in Chinese material (e.g. Qi et al. 2009). The larva is typical for Paratendipes , including with the proximal Lauterborn organ pedicellate, originating prior to the apex of the segment, rather than sessile on the apex as the distal. This pedicellate proximal Lauterborn organ occurs in several larvae allocated to Paratendipes , although on a very short segment it is nearer the apex. This structure seems not to occur in other genera with alternate Lauterborn organs on a 6 segmented antenna. This condition needs to be examined at oil immersion magnification, with phase contrast to allow interpretation: illustrations may not represent accurate observations.

Paratendipes sinespina is restricted to the northern monsoonal seasonal tropics associated with sandy-bedded but perennial creeks. Although a suite of congeners from more temperate Australia are yet to be differentiated, P. sinespina is the dominant Australian tropical species of the genus, but larvae are rare in contrast to the abundant pupal exuviae.

Discussion. Detailed examination of the morphology of all life stages of the monotypic genera Parvitergum and Paraborniella shows both similarity and distinction from each other, and each from Paratendipes . Nothing refutes the molecular evidence, albeit derived from limited taxon sampling. The morphology of these genera support the current status and any synonymy would be premature without global study inclusive of all taxa related to Paratendipes . Interestingly, Imparipecten a genus of Chironomini described on the adult by Freeman (1961), after remaining monotypic for over 50 years, has larvae in south-east Asia ( Cranston et al. 2011) and recently was found in South America ( Fusari et al. 2018). Fears of taxonomic redundancy inherent in description of monotypic higher taxa are tempered by such examples.

Figures

FIGURE 8. Paratendipes sinespina sp. n. male (except B). A. Wing; B. Thorax lateral (♀), C. Thorax lateral (♂); D. Foretibial apex; E. Inner spur and comb of hind tibia; F. Hypopygium, left side hypopygium, dorsal view; G. ventral view, right side (stylised); H–J. Superior volsella: H, dorsal, I. ventral, J. dorso-lateral view of apex; K. Median volsella.

FIGURE 9. Paratendipes sinespina sp. n. Pupa. A-D: A. Cephalic area; B. base of thoracic horn; C. Abdomen; D. Posterior of VIII (‘comb’). Larva: E. Antenna; F. Labrum-epipharynx; G. Mandible; H. Mentum and ventromental plate.

FIGURE 10. Paratendipes sinespina sp. n. Larva. A. Antenna (inset, apical segments); B. Mentum; C. Ventromental plate; D. Labrum-epipharynx; E. Mandible.