Cricotopus tasmania Drayson & Cranston

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 : 18-19

Cricotopus tasmania Drayson & Cranston sp. n.

(Figs IH, 3C, 4H, 5F, 6H, 7I, 9C, 12A)

urn:lsid:zoobank.org: act :54846590-FE9A-439F-AB06-8B67ACF23663

Cricotopus ‘sp. E’ Drayson, 1992: 109

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

Type material. Holotype: ♂, AUSTRALIA: Tas, Mt. Field NP, Rodway Hut, 1200m. 42°41'S 146°34'E, 3.ii.1992 (Cranston) ( ANIC). Paratypes: 10 Pe, L/P, 2 L, as Holotype; Tas: 3 Pe, Lake St.Clair NP, Ranger Hut, Douglas Ck., 41°50'S 146°02'E, 25.i.1990 (Cranston).

Other material examined. Qld: 3 Pe, Eungella NP, Mt Dalrymple,? Cattle Ck., 21°02S 148°35'E, 22.iii.1998 (Cranston). Tas.: 10 Pe, L/P, 2 L; Mt. Field NP, Rodway Hut, 1200m. 42°41'S 146°34'E, 3.ii.1992 (Cranston).

Molecular material. ACT : ♂, Corin Rd, Gibraltar Falls, 35°28'S 148°55'E, 3.vii.2012 (Cranston) (Mv- ACTGF 27); 2♀, Brindabella, Goodradigbee R., 35°23'S 148°44'E, 27.vi.2012 (Cranston) (Mv-NSWGd11, 12). NSW: 2L, Bramina Ck., 35°23'S 148°44'E, 27.vi. 2012, 543 m asl, (Cranston) (Mv-NSWBramCr1, 2); Kosciuszko NP, L, trib. Bogong Ck., 36°21'S 148°02'E, 4.xii.2010 (Cranston) (Mv-KNPCric3); P♀, Pipers Ck., 36°23'S 148°26'E, 2.xii.2010 (Cranston) (Mv-KNPCric6); P♂, L, Leather Barrel Ck., 36°31'S 148°11'E, 4.xii.2010 (Cranston) (Mv-NSWKos13, 14). Tas: L, Devil’s Gulch Res., unnamed Ck., State Forest Rd, 41°38'S 146°17'E, 25.xi. 2013, 838 m asl (Krosch) (Mv-Tas13.1.3); L, Cradle Mountain NP, Pencil Pine Ck., 41°35'S 145°55'E, 26.xi. 2013, 811 m asl (Krosch) (Mv-Tas13.2.3); 3L, Cradle Mountain NP, Fagus Ck., 41°38'S 145°56'E, 27.xi. 2013, 920 m asl (Krosch) (Mv-Tas13.3.1, 3.12); 3L, Lake Saint Clair NP, unnamed Ck., 42°06'S 146°10'E, 1.xii. 2013, 764 m asl (Krosch) (Mv-Tas13.7.3, 7.7, 7.9); 2L, Mt Field NP, Rodway Hut, 42°41'S 146°34'E, 2.xii.2013, 1242 m asl (Krosch) (Mv-TAS13.8.1, 8.2); L, Mt Field NP, Russell Falls Ck., 42°40'S 146°42'E, 3.xii.2013 (Krosch) (Mv-TAS 13.9.14); L, Mt Field NP, Tyenna R., 42°41'S 146°43'E, 3.xii. 2013, 165 m asl (Krosch) (Mv-TAS 13.10.14).

Description. MALE (Fig. IH) (n=3, partial). 4.1–4.2 mm.

Head. Ant 960 µm; Fl 1–12, 440–480 µm, Fl 13, 520–535 µm; A.R. 1.1–1.2. Palp 490–690 µm. Fr 2–4, Po 8. Clyp sparsely setose (c 8 setae).

Thorax. Uniform mid-brown. Laps 2–3, Ac 17–23, Dc 15–21, Pa 2–3, Scts 7–10.

Wing. 2.4 mm. Sq 7–11, R 8, R4+5 0.

Legs. All legs very pale yellow-brown; without dark section(s).

Abdomen. TI and IV totally pale; broad anterior pale band on TII, narrower pale band anterior on V, evidence of pale anterior band on VI–VII.

Hypopygium ( Fig. 3 C). Gcx 245–248 µm, iv somewhat squared off. Gst 83–90 µm, 0.36 x Gcx, with triangular pointed to elongate rounded crista dorsalis.

FEMALE. ( Fig. 4 H) (n=1–2, partial). As male except: 4.2–4.6 mm.

Head. Ant 325–365 µm. Palp 420–690 µm. Co 0, Fr 2, Po 5, Clyp setose (c 20 setae).

Thorax. Vittae mid-brown against yellow background. Laps 2, Ac unviewable, Dc 18, Pa 5, Scts 10.

Wing. 2.6–2.7 mm. Sq 10–11, R + R 1 12–15, R4+5 0.

Genitalia. Spermathecae comprising mid-brown, variably ovoid to elongate-oval capsules tapering into long "neck" and ducts variably curved according to pressure on specimen ( Fig. 4 H, left specimen #Mv-Gd11, right #Mv-Gd12).

PUPA. 3.5–4.1 mm, pale to mid-brown.

Cephalothorax. Moderately rugose dorsally. Th 14–80 µm; hyaline to pale brown, variable in shape (see Fig. 6 H), may have apical scales ( Fig. 7 I). 0 Fs.

Abdomen ( Fig. 9 C). PSB on II only. TII with hook row>1/2 width of segment (0.27–0.44); narrow sparse spinule field anterior to hook row; two medio-Iateral spinule fields usually present. VIII with 5 prominent Ls (100–160 µm), Ls4> 1/4 width of segment (0.27–0.33) ( Fig. 5 F). Ms 160–200 µm, <1/12 length of abdomen (0.06–0.07).

4TH INSTAR LARVA (Fig. 12A) (n=4). 4.2–5.6 mm. H.l. 480–550 µm mid-brown with dark brown posterior margin; abdomen yellow-blue; procercus hyaline with mid-brown marking.

Head. Ant 72–90 µm; 1, 40–54 µm; 2–5, 32–36 µm; A.R. 1.25–1.69. Md with serrate inner and smooth outer margin, mid-brown with distal 1/3 dark brown; length 156–180 µm, about 2x antenna (1.98–2.18). Mentum 112–148 µm, mid-brown; 6 pairs laterals, 2nd slightly reduced.

Abdomen. Pc 22–27 µm, A.s. 500–530 µm.

Etymology. The epithet ‘ tasmania’, a noun in apposition, derives from its original collections suggesting endemism to Tasmania . We retain the name although there is molecular evidence showing the species presence in high elevation alpine and sub-alpine streams in south-eastern mainland Australia.

Remarks. Adults of C. tasmania can be distinguished by their uniformly pale legs, pattern of pale tergites and in the male the A.R. is unusually low. Pupae can be recognised by the presence of spine/spinule fields on TII and by the usual presence of 5 long L setae on VIII. Specimens from mainland Australia seemingly can lack the distinctive 5th L seta on VIII, but whether this is damage or true absence is unclear. Larvae can be recognised by the mandible having a smooth outer margin, serrate inner margin, and being narrow above the mola. The validity of the colour contrasts used in the key need verification.

The adult of this species resembles in colour and pattern C. phaeosomatus described by Hergstrom (1974), but differs in having the A.R. of adult males much less than the value of 1.9 (as inverse 0.53 of Hergstrom, and confirmed by Cranston).

Molecular data suggest monophyletic non-Tasmanian specimens are embedded in a diversity of Tasmanian sampled specimens (Krosch et al., submitted).

C. tasmania inhabits clean cool streams often at elevation, in south-east Australia including Tasmania where it appears widespread.

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 6. Cricotopus pupa, thorax and thoracic horns. A. C. albitarsis, B. C. annuliventris, C. C. brevicornis, D. C. conicornis, E. C. hillmani, F. C. howensis, G. C. parbicinctus, H. C. tasmania.

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.