Cricotopus wangi Cranston & Krosch

Drayson, Nick, Cranston, Peter S. & Krosch, Matt N., 2015, Taxonomic review of the chironomid genus Cricotopus v. d. Wulp (Diptera: Chironomidae) from Australia: keys to males, females, pupae and larvae, description of ten new species and comments on Paratrichocladius Santos Abreu, Zootaxa 3919 (1), pp. 1-40 : 21-22

Cricotopus wangi Cranston & Krosch sp. n.

( Fig. 3 E, 5A,D, 9E, 12C)

urn:lsid:zoobank.org: act :52659DBB-8F1F-471B-BF66-3047F4C10C8E

Cricotopus “wongi” sp. nov. Cranston, in Cranston, 1996: 86 [Invalid; author states ‘not formal publication for nomenclatural purposes]

Type material. Holotype: Le/Pe/♂, AUSTRALIA: NT, Litchfield NP, Wangi Falls, 13°10'S 130°41'E, 6.viii.1990 (Cranston). Paratypes: Le/Pe/♀, Le/Pe, 4L, as holotype; Le/Pe, Pe, NT/Qld, Border Waterhole, 18°37'S 137°59'E, 19.v.1995 (Cranston); WA, Hamersley Range NP, Fortescue Falls, Circular Pool, 22°28'S 118°33'E, 23–24.iv.1992 (Cranston).

Molecular material. 2P, 2L, as holotype except 29.vii.2014 (Cranston & Krosch) (Mv-NT14.1.P1, P2, NT14.1.1, 1.3); L, Kakadu NP, Rockhole Ck., 13°34'S 132°15'E, 30.vii.2014 (Cranston & Krosch) (Mv- NT14.3.1); 2P, 3L, Kakadu NP, Gimbat, Upper S. Alligator R., 13°34'S 132°36'E, 31.vii.2014 (Cranston & Krosch) (Mv-NT14.6P1, P2); 3P, 2L, Kakadu NP, Gunlom, Waterfall Ck., 13°25'S 132°25'E, 1.viii.2014 (Cranston & Krosch) (Mv-NT14.7.P1-3).

Description. MALE (n=1, immature pharate). 3.0 mm.

Head. Ant 505 µm; Fl 1–12, 300 µm, Fl 13, 225 µm; A.R. 0.75. Palp 308–324 µm. Clyp sparsely setose, 9.

Thorax. Brown. Laps 2–3; Ac 20, Dc 20 biserial. Pa and Scts not visible.

Wing, legs and abdomen not measurable.

Hypopygium ( Fig. 3 E). Gcx 175, iv with medio-posteriorly rounded lobe; Gst 85 µm, about 1/2 (0.48) gcx; crista dorsalis not developed.

FEMALE (n = 1, pharate). 3.2 mm.

Head. Ant 245 µm. Fr 2, Po 2, Clyp 17; Palp 350 µm.

Thorax. Laps 2, Ac 9, Dc 20–21, Pa 2–4, Scts 6–8.

Wing, legs and abdomen not measurable.

Genitalia. Spermathae comprising ovoid capsules with tapering "neck" and gently curved ducts (as in Fig. 4 B).

PUPA (n=6). 2.7–3.2 mm, pale to mid-brown.

Cephalothorax. Moderately rugose dorsally. Th 100–138 µm, width 37–50 µm; hyaline, elongate ovoid, without apical scales or spines ( Fig 7 B). Fs 120–138, long, semi-taeniate, on frons ( Fig. 5 A).

Abdomen ( Fig. 9 E). PSB on I, II and III. Hook row broad, about 2/3 of segment (0.65–0.72). No spinules or spines on TI or anterior to hook row on TII; anterolateral patches of very weak spinules on VII, VIII and IX. Paraterga bare. Ls 3 VIII 20 –25 µm, <1/15 segment width (0.06) ( Fig. 5 D).

Ms 60–80 µm, anteriormost displaced medially from margin 44–70 µm, <1/25 length of abdomen (0.04).

4TH INSTAR LARVA (Fig. 12C). 3.7–4.1 mm. H.l. 350 µm, dark-brown; mandibles, mentum, occipital margin black; thorax yellow-green, abdomen blue-pigmented; procercus hyaline; procercal anal setae and posterior parapod claws black.

Head. Ant 52–55 µm; 1, 30–32 µm; 2–5, 21–22 µm; A.R. 1.36–1.41; blade 25–27 µm extending beyond apical segment.

Md 107–120 µm, outer margin strongly crenulate, inner smooth, completely dark brown (a little paler basally); seta subdentalis a spine.

Mentum 80–85 µm, dark brown; 6–7 pairs laterals, first well developed, second slightly reduced, outermost mentum may be worn or appressed with 7th lateral indistinct.

Abdomen. l4 seta not plumose. Pc very short, with brown pigment patches, 12–14 µm, A.s. 250–280 µm.

Etymology. The epithet wangi derives from the name of the waterfall in Litchfield National Park, Northern Territory where the first specimens were collected (although in manuscript spelled as ‘wongi’). The name is a noun in apposition.

Remarks. The combination of long frontal setae located on the frons, short L setae on VIII, hyaline nonspinose thoracic horn and short anal macrosetae with displaced basal setae allow easy recognition of the pupa of C. wangi . Larvae are characterised by the fully dark head capsule, including all-dark mandible. The mandible has strong crenulations on the outer margin and smooth mola, with a simple lance-shaped seta subdentalis. The antenna is uniquely short, maximally 55 µm long.

Cricotopus wangi sp. n. appears to be restricted to northern Australia where the immature stages live on hygropetric surfaces of waterfalls, with few exceptions in riffles in permanent creeks.

Figures

FIGURE 3. Cricotopus male genitalia, part. A. C. howensis, B. C. parbicinctus (inset variation in inferior volsella above, gonostylus below), C. C. tasmania, D. C. varicornis, E. C. wangi. Tergite III, IV setation: F. C. varicornis, G. C. hillmani.

FIGURE 4. Cricotopus female. Spermathecae. A. C. acornis, B. C. albitarsis, C. C. annuliventris, D. C. brevicornis, E. C. conicornis, F. C. hillmani, G. C. parbicinctus, H. C. tasmania, I. C. varicornis.

FIGURE 5. Cricotopus pupa. Frons: A. C. wangi, B. C. howensis, C. C. parbicinctus. Lateral segment VIII: D. C. wangi, E. C. annuliventris, F. C. tasmania. Anal lobe: G. C. wangi. Anterior tergites: H. C. brevicornis, I. C. varicornis.

FIGURE 7. Cricotopus pupa, thorax and thoracic horn. A. C. varicornis, B. C. wangi. Variation in thoracic horn shape and size (all drawn to scale). C. C. albitarsis, D. C. annuliventris, E. C. brevicornis, F. C. conicornis, G. C. hillmani, H. C. parbicinctus, I. C. tasmania, J. C. varicornis s. s., K. C. varicornis f. cooki.

FIGURE 9. Cricotopus pupa, tergites. A. C. howensis, B. C. parbicinctus, C. C. tasmania, D. C. varicornis, E. C. wangi.