Paraborniella tonnoiri Freeman, 1961

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 : 535-539

Paraborniella tonnoiri Freeman

( Figs 4–7 )

Paraborniella tonnoiri Freeman 1961: 717 ; Cranston 1996, 2000

Material examined (collected Cranston, deposited ANIC unless stated). AUSTRALIA: New South Wales: 2L, Pe / ♂, ♀, Beardy Waters, 6 ml n.e. Glen Innes, 29º06’S 151º46’E, 24.i.1969 (Martin) , from egg mass; 2L, Le / Pe / ♂, 2 km n.e. Nerriga, roadside drain, 35º06’S 150º07’E 2.ix.1988 ; 2L(3i), Morton N.P., 5–8 km. s. Sassafras, 35º08’S 150º16’E, 1.ii.1988; 4♂, Oallen, ‘Neverdie’, 35º07’40”S 150º00’44”E,. ix.2016 .

South Australia: Le / Pe / ♂, Pildappa Rocks , 22º32’S 134º21’E, 27.ii.1969 (R.E. Jones) det. D.H.D. Edward.

Western Australia, 5 L, Mt. Lesueur , site 10, 24.viii.1990 (Edward), ‘VML1’, det. D.H.D. Edward ; 4L, Yorkrakine Rock , 31º42’S 117º30’E, 19.viii.1985 (Edward) det. D.H.D. Edward.

Northern Territory: 2 Pe, West MacDonnell Ranges, Serpentine Gorge (inner), 22º35’S 132º31’E, 8.iii.1995 ; 6L, Kata Tjuta, Valley of the Winds , 25º20’S 130º43’E, 5.vi.1992 .

Description (genus and species). Adult Male (n=5–8). Body length 1.9–2.4 mm, wing length 1.7–2.1 mm. Wing hyaline, plain. Alcohol-preserved and slide-mounted dark brown.

Antenna. With 13 flagellomeres; Fl 1-12 350–450, Fl 13 650–820; A.R.1.6–2.0. Apex squared off ( Fig. 4B ).

Head. Eye bare, with dorsomedial parallel-sided extension 5–6 ommatidia long, separated medially by width of 10 ommatidia. Temporals 9–14; clypeals 12–13. Frontal tubercles absent. Palp 5-segmented, segment 2 globular, segments 3 and 5 subequal in length, 4th shorter (210–340 μm); segment 3 lacks sensilla.

Thorax. Antepronotal lobes tapering dorsally, slightly divided medially at notch, without lateral antepronotal setae. Scutum curved in profile without tubercle, not overreaching antepronotum. Without humeral pit. Ac 12–16, uni-biserial starting from front, ending mid-thorax; Dc 8–15 uniserial, each arising from small pale spot; Pa 3–5; Scts 8–13, uniserial.

Wing ( Fig. 4A ). Membrane without setae or microtrichia. Anal lobe moderately developed. Costa ends at apex of R 4+5 both terminating just prior to wing tip. R 2+3 distinct and ending 1/3 distance apex of R 1 and R 4+5’ FCu distal to RM, VR 1.1–1.2. Brachiolum with 2 setae. R, R 1, setose, R 4+5 bare. Squama with 5–6 setae.

Leg. Apex of fore leg tibia with rounded scale, without spur ( Fig. 4C ). Mid and hind Ti apically with two slightly separated combs, combined occupying about 50% circumference, shorter comb with curved spur ( Fig. 4D ), the wider comb lacking spur. Leg ratios: LR 1 1.42–1.60, BV 1 1.58–1.85, SV 1 1.46–1.56; LR 2 0.56–0.57, BV 2 2.56–2.67, SV 2 3.48–3.69; LR 3 0.79–0.82, BV 3 1.9–2.0, SV 3 2.5–2.6. Pulvilli absent, empodium weak.

Abdomen. Tergites I–VII with dense irregularly-distributed setae.

Hypopygium ( Fig. 4 E–I). Anal tergite with neither bands nor setae, microtrichia extending onto base of anal point, with many setae baso-laterally along submargin of tergite IX. Anal point relatively short, bare apically, near parallel–sided with rounded apex ( Fig. 4F ). Superior volsella ( Fig. 4H ) 70–80 long, swollen almost bi-lobed, basal dorsal area with 2–3 longer curved setae towards outer margin, arising from paler ovoid-rectangular microtrichiose area, becoming darker and curved medially to taper to weak point or hook. Median volsella ( Fig. 4I ) 65–70 long with distinct stem (15 long), distally with 2–3 longer and several shorter taeniate setae. Inferior volsella free from gonocoxite from its base, elongate with dorsal longitudinal ridge bearing numerous long simple setae mostly directed antero-medially, without long setae in macrotrichiose lateral and part dorsal surface, extending to mid-gonostylus, without distinct apical seta. Transverse sternapodeme dark, squared-arched; phallapodeme weak ( Fig. 4G ).

Adult Female (n=1) (unknown to Freeman, 1959)

As male except: Body length 3.2 mm, wing length 5.5 mm.

Head. Antenna ( Fig. 5A ): 5-segmented, lengths: 105; 65; 70; 80; 165; A.R. 0.5. Temporals 9–10, clypeals 18. Palp 2–5: 50, 150, 165, 215.

Thorax. Ac uniserial, c. 10, Dc 12 uniserial, including 2 isolated humerals, 3 Pa; 8 Scts.

Wing. VR 1.3. Setation: R 17, R 1 22, R 4+5 33; sq 9–10.

Legs. P 1: 255, 185, 195, 110, 95, 60, 40; LR 1 1.05, BV 1 2.28, SV 1 2.08; P 2: 250, 235, 130, 65, 60, 35; LR 2 0.55, BV 2 3.7, SV 2 2.56; P 3: 1129, 1120, 760, 480, 400; 160; LR 3 0.67, BV 3 3.0, SV 3 2.94.

Genitalia ( Fig. 5B, C ). Notum robust 225 long, with strong rami making 300 total. Dark, strong gonocoxapodeme curved 'under' (dorsal to) gonapophysis VIII and fused medially via weakly sclerotised section. Coxosternapodeme IX strongly sclerotized, anteriorly curved to traverse notum. Labia well developed, with hyaline scales.

Seminal vesicles ovoid, large, 175 long, maximum width 100, with tapering dark brown neck before curved (maybe forming one loop) spermathecal ducts ending separately. Gonocoxite IX protruding, with 4–5 long setae. Cerci 125 long by 50 wide. Gonapophysis VIII with large microtrichiose dorsomesal lobe, continuous with inner contour of vagina; ventrolateral lobe either lacking or perhaps represented by few short scales. Postgenital plate elongate, densely setose.

Pupa. Medium-sized, c. 4.0–5.0 mm long. Cephalic area and thorax pale gold with brown tinged margins to appendages, abdomen pale hyaline with little indication of darker apophyses, comb and anal lobe.

Cephalothorax. Frontal apotome weakly wrinkled, without frontal warts; frontal setae (c. 50 μm) located on conical cephalic tubercles (50–60 μm), apex blunt or pointed sclerotised ‘nipple’ ( Fig. 6A ). Thoracic horn comprising 6 stout smooth hyaline branches, longest 600 μm; basal ring oval and with well-developed tracheal ‘bundle’. Median suture smooth anteriorly, tuberculose medially. Prealar tubercle absent. Antepronotal and thoracic setae uncertain; 2 precorneals, others including dorsocentrals not determinable in specimens available.

Abdomen ( Fig. 6 B–D). Tergite I bare, II–V each with broad anterior band of slightly stronger spinules merging posteriorly in more-or-less subquadrate pattern; TVI spinulation stronger anteriorly, weaker posteriorly, TVII with only anterior fine spinulation, TVIII and anal lobe bare ( Fig. 6B ). Tergite II hook row discontinuous, comprising 17–20 hooks each side, c. 40% width of segment II, narrowly but clearly separated medially. Broad transverse spinule bands on conjunctive IV is scarcely separated from more anterior spinule area. Pleurae of III and IV with few scattered spinules. Sternites bare except for SIV with fine laterally-directed spinules of <4 μm ( Fig. 6C ). Vortex on IV larger and more anteriorly located than usual. Pedes spurii B developed, on segment II only. Posterolateral corner of segment VIII (‘comb’) with 8-11 brown sharp teeth, none dominant ( Fig. 6D ). Apophyses weak.

Segment I with 2D, 3V and without L setae; II with 3D, 3V and 3 L; III with 4D, 3V and 3L; IV–VII with 5D, 3–5 V and 4 taeniate LS, VIII with 1D, 1V and 4 taeniate LS. O setae very fine, present on TII–VII, uncertain ventrally, but present on sternite IV.

Anal lobe elongate semicircular with fringe of 30–40 taeniae, uniserial anteriorly, unevenly biserial posteriorly, with dorsal seta. Genital sac of male extends beyond anal lobes; of female unknown or male-like.

Larva (4th instar) (n=10). Body ( Fig. 7E ) bright red in life, up to 10 mm long. Ventral head length c. 500 μm. Head capsule pale yellow with golden-brown dorsomental, apical mandibular and premandibular teeth. Genae and submentum pale to slightly darkened; occipital margin narrow, dark.

Dorsal head ( Fig 6E ) with frontoclypeus narrowed anterior prior to subterminal flare to lateral points, without frontal pit. Cephalic S3 (clypeal) setae close to anterior margin, S2 seta on broad granulose area, S1 outside of labrum.

Antenna ( Fig. 6F , 7A ) 6-segmented, with segments 2, 3, 4 subequal, each longer than shorter 5th and short 6th; 62–75; 15–17; 15–20; 14–20; 8–12; 5–7; A.R. 0.95–1.25; Lauterborn organs well developed (12–15 long), sessile, alternate on apices of 2nd and 3rd segments. Ring organ in basal 1/4 of segment 1, lying distal to extended weaklysclerotised, elongate-ovoid region (‘pouch’?), seta absent. Blade extends to mid-4th segment, much shorter than antennal flagellum, accessory blade short.

Labrum ( Figs 6G , 7D ). Labral SI on separated bases, broadly plumose; SII serrate apically, widely separated at origin. SIII simple, short; SIV moderately developed. With 7–8 plumose chaetae. Seta premandibularis simple. Lamellae finely-toothed, broad, undivided plate. Pecten epipharyngis comprising three separate lobes each with 5–7 rounded teeth, variably sized in some specimens. With 7–8 apically plumose chaetulae laterales, 2 apically branched chaetulae basales. Premandible with 2 teeth, with strong brush.

Mandible ( Fig. 6H , 7B ) with short pale dorsal tooth, darker larger apical tooth and 2 modest inner teeth; distal mola darkened not tooth-like. Pecten mandibularis weak, but extending to margin of mandible. Seta subdentalis squat, retracted on mola arising from ventral surface, parallel-sided to rounded apex, ending level with 2nd inner mandibular tooth. Mola and inner margin smooth. Seta interna quite densely plumose.

Mentum ( Fig. 6I , 7C ) with delimited ventromentum of 8, uneven-sized, teeth; dorsomentum on each side with 4 teeth rather darker than ventromentum, each diminishing slightly in size laterad. Ventromental plates fan-shaped, widely separated medially, about 2 times as wide as high, subequal in width to mentum, curved and moderately striate. Striae dense, narrow, almost straight, arrayed across the plate. Setae submenti simple.

Body ( Figs 7D, E ). Without lateral or ventral tubules. Anterior parapod claws dense, fine, simple, pale; posterior parapods claws pale, simple. Procercus weakly pigmented, small, as high as wide, bearing 7–8 anal setae. Anal tubules short, rounded.

Discussion. The adult male of Paraborniella was described by Freeman as having genitalia very similar to Paratendipes . In the Holarctic key to males of subfamily Chironominae ( Cranston et al. 1989) Paraborniella with 13 flagellomeres and foretibae lacking scale and spur would group with Microtendipes with fringed squama, whereas the bare squama would arrive at Apedilum and Paralauterborniella . However the key errs in that the Paratendipes albimanus group has squamal setae. Microtendipes is denied by Paraborniella lacking the diagnostic apicomedian patch of posteriorly-directed setae on the fore-femora.

As recognised by Saether (1977) the female adult of Paraborniella would key with Parvitergum and Paratendipes based solely on non-genitalic features. Using the Holarctic key to pupae, Paraborniella would head towards Microtendipes and Paralauterborniella but the latter has 4L on II–IV, and a ‘nose’ on the wing. Other genera in the ‘Microtendipes’ group are eliminated by permutations of the number and distribution of taeniate LS setae, the presence of frontal setae and developed pedes spurii B. The somewhat similar Kribiodorum Kieffer (= Stelechomyia ) also differs in the distribution of LS setae. The key did not purport to be phylogenetic, lacks many austral genera and as such, multivariate diagnostic features are ineffective here.

Concerning the larva, Paraborniella keys in Cranston (1996, 2000) with cluster of genera with alternate Lauterborn organs, and in the regional key of Cranston (2019b) it is separated from Paraskusella ( Cranston 2018) by a different median mentum structure.

Molecular data suggested that Paraborniella was proximate (but without support) to Paucispinigera the sister taxon to Microtendipes amongst the genera sampled ( Cranston 2011). Other putatively related genera sampled for molecular data, namely Apedilum Townes , and Zavreliella Kieffer + Lauterborniella Thienemann & Bause form a well-supported cluster as sister to Skusella Freeman + Conochironomus Freeman , in turn sister to Paratendipes Kieffer + Paralauterborniella Lenz. This inclusive clade, informally termed the ‘ Microtendipes group’, finds subsequent support including from an expanded molecular analysis by Han et al. (2020), although it was not recovered in the large and densely sampled morphological analysis of Andersen et al. (2017).

Figures

FIGURE 4. Paraborniella tonnoiri Freeman, male. A. Wing; B. Antennal apex; C. Foretibial apex; D. Hind tibial inner comb; E. Male hypopygium (from Freeman 1961); F. Left side hypopygium, dorsal view; G. ventral view, right side (stylised); H. Superior volsella (dorsal); I. Median volsella.

FIGURE 5. Paraborniella tonnoiri Freeman, female. A. Antenna; B. Abdomen, dorsal; C. somewhat stylised ventral genitalia.

FIGURE 6. Paraborniella tonnoiri Freeman, pupa.A. Cephalic area; B. Abdomen, tergites; C. Sternite IV; D. Posterior of VIII (‘comb’). Larva: E. Anterior dorsal head; F. Antenna; G. Labrum; H. Mandible; I. Mentum and ventromental plates.

FIGURE 7. Paraborniella tonnoiri Freeman, larva. A. Antenna (b. ‘pouch’ on segment 1, c. with flagellum); B. Labrum, epipharynx, mandible; C. Mentum and ventromental plate; D. Head, anterior body; E. Habitus.