Cricotopus annuliventris (Skuse)

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 : 8-10

Cricotopus annuliventris (Skuse) .

( Figs 1 C, 2C, 4C, 5E, 6B, 7D, 8C, 10C)

Orthocladius annuliventris Skuse, 1889: 255

Cricotopus annuliventris (Skuse) ; Freeman, 1961: 646. Cricotopus annuliventris (Skuse) ; Drayson, 1992: 81. Cricotopus annuliventris (Skuse) , Cranston 1996: 86

Type material. Lectotype ♂ here designated: AUSTRALIA: Lawson [no further data, specimen ex-Macleay collection] slide-mounted in Euparal from dry specimen by Cranston. Pinned specimen bears red Lectotype label ‘ Orthocladius annuliventris Skuse’ in black ink, but designation (by unknown person) appears to be unpublished. Paralectotype, ♂ as Lectotype.

Other material examined. Qld.: Pe, Eungella NP, Mt Dalrymple,? Cattle Ck., 21°02S 148°35'E, 22.iii.1998 (Cranston). NSW: ♂, Le/Pe/♀, Sugarloaf Ck., Clyde Mt., 35°33'S 149°58'E, 10.i.1988 (Cranston); 1 Pe, Albury, Murray R. Stn 6, 36°06'S 147°01'E, 17.v.1989 (Cook); 2 Pe, Jindabyne, Rush's Ck., 12.xii.1987 (Cranston); 8♂, Le/Pe/♀, 3 Pe, Rutherford Ck., Brown Mt., 36°36'S 149°47'E, 17.xii.1990 (Cranston). ACT : 2♂, ♀, Canberra, Black Mt., 35°17'S 149°05'E, 29.vii.1989 (Reid); 3♂, 4♀, Corin Rd, Gibraltar Falls, 35°28'S 148°55'E, 29.x.1990 (Drayson). Vic: Pe, Wodonga, House Ck. up-stream, 36°10'S 146°52'E, 19.xii.1989 (Cook); Pe, Mitta R., 10km E. Mitta, 36°32'S 147°25'E, 30.x.1989 (Cook). SA: ♂, 4L, Cox Ck., Bonython Rd, 29.ix.1989 (Madden); ♂, 2L, Piccadilly Valley, Vince Ck., 29.ix.1989 (Madden).

Molecular material. NSW: L, Kosciuszko NP, sphagnum bog, 36°26'S 148°20'E, 2–3.xii.2010 (Cranston) (Mv-NSWKos1); L, Kosciuszko NP, stream next to Wright's Ck., nr 36°7'S 148°20'E, 3.xii.2010 (Cranston) (Mv- KNPCric8); P, Kosciuszko NP, Wragge's Ck., 36°23'S 148°27'E, 1.xii.2010 (Cranston) (Mv-KNPCric13); 3L, Warrumbungles, Castlereaigh R., 31°16'S 149°11'E, 27.vii.2005 (Cranston) (Mv-NSW2M1, 2, 5). ACT : ♂, P, Condor Ck., 35°22'S 148°51'E, 14.vi.2012 (Cranston) (Mv-ACTCon 6, 7). Vic: L, Dobson’s Lane, Dandenong Ck., 37°50'S 145°19'E, 24.x.2006 (Carew) (Mv-DOL3). SA: L, P, ♀, below Hindmarsh Falls, Hindmarsh R., 35°26'S 138°58'E, 3.x. 2013, 220 m asl (Krosch & Cranston) (Mv-HF3, HFP 1, SAHF 3.1); 2L, Deep Creek Conservation Park, Tapanappa Rd, 35°36'S 138°14'E, 3.x. 2013, 260 m asl (Krosch) (Mv-DC1, 4). Tas: Mt Field NP, Russell Falls Ck., 42°40'S 146°42'E, 3.xii. 2013, 196 m asl (Krosch) (Mv-TAS13.9.2).

Description. MALE ( Figs 1 C, 2C) 2.8–4.2 mm.

Head. Ant 832–1088 µm; Fl 1–12 392–480 µm, Fl 13, 416–448 µm. A.R. 0.91–1.19. Palp 424–592 µm. 2 Fr; 6–10 Po.

Thorax. Uniform mid- to dark brown. Lapn 1–5, Ac 15–28, Dc 18–25, Pa 2–4, Scts 6–10.

Wings. 2.0– 2.7 mm. Sq 7–15, R 2–9.

Legs. Femora mid-brown: tibiae of fore and mid-legs with white ring on proximal third. Distal 2/3 of fore and mid-tibiae, all of hind tibia and all tarsomeres mid-brown.

Abdomen. TI very pale; broad anterior pale bands on TII, IV,V, and VI, not III; narrow posterior pale bands on TIV, V, and VI; otherwise mid- to dark brown.

Hypopygium ( Fig. 2 C). Gcx 180–250 µm, iv rounded and usually notched posteriorly. Gst 66–100 µm, about 2/5 Gcx (0.35–0.45); crista dorsalis large, bare and hyaline.

FEMALE (n=6). As in male except: 4.1–4.3 mm.

Head. Ant 337–428 µm. Palp 544–644 µm.

Wing. 2.0– 2.7 mm. Sq 8–13, R + R 1 17–19, R4+ 5 13–15.

Abdomen. As male.

Genitalia. Spermathecae comprising mid-brown, spheroid capsules, with very narrow "neck" and recurved ducts ( Fig. 4 C).

PUPA ( Figs 7 D, 8C). 3.5–4.7 mm, pale brown to very pale, almost hyaline.

Cephalothorax. Slightly rugose dorsally. Th 56–114 µm; hyaline, cylindrical, tapered to point, covered with sparse scales, especially distally. 0 Fs.

Abdomen. PSB on II and sometimes much reduced on III. Hook row on T II always <0.5 width of segment (0.35–0.47). Ls on VIII long, Ls4 about 1/4 width of segment (0.22–0.31) ( Fig. 5 E). Ms 80–96 µm, <1/12 abdomen length (0.06–0.08).

4TH INSTAR LARVA ( Fig. 10 C) (n = 9). 3.5–5.4 mm. H.l. c 650 µm pale to mid-brown with mid-to dark brown posterior rim; abdomen hyaline; procercus usually hyaline, sometimes with pale brown marking.

Head. Ant 72–86 µm, 1st 42–52 µm, 2–5 28 –341 µm; A.R. 1.40–1.64. Md 144–160 µm, with smooth outer margin and serrate inner margin, pale brown with distal 1/3 mid-to dark brown. Mentum 120 µm, pale brown basally, mid-brown distally; 6 pairs laterals, 2nd slightly reduced.

Abdomen. Pc 18–28 µm, A.s. 560–700 µm.

Remarks. Adults of this species can be distinguished by the pale bands on legs being restricted to the fore and mid-tibiae, and by pale bands on abdomen TII, IV and V, but not on III. Pupae can be recognised by lack of frontal setae, presence of medio-lateral spinule fields on TII with none developed as a spine band, and with 4 long Ls on VIII. Larvae can be recognised by a combination of mandible with smooth outer and serrate inner surfaces, antenna length less than 90 µm, and AR less than 1.64. Adult specimens perfectly fit the descriptions of Freeman (1961) and Hergstrom (1974). A highly genetically divergent larval form is recognized from three specimens from the Castlereaigh River (Warrumbungles, NSW). These specimens do not cluster with other C. annuliventris (Krosch et al., submitted), but form a group unto themselves, and with some relationship to both C. annuliventris and C.

tasmania . On morphology these larvae key to C. annuliventris , but may be differentiated by the mandible pigment extending to the base with less strong contrast to the mid-brown head capsule, a narrow mola, a broad rounded median mentum tooth and second lateral mentum teeth no smaller than the first laterals.

C. annuliventris is restricted to south-east Australian cool streams, often at elevation and shaded. All sites are unpolluted.

Figures

FIGURE 1. Cricotopus adult males. Columns (left to right): legs, anterior to posterior; thorax; dorsal abdomen. 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 2. Cricotopus male genitalia, part, (inset variations in inferior volsella above, gonostylus below). A. C. acornis, B. C. albitarsis, C. C. annuliventris, D. C. brevicornis, E. C. conicornis, F. 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 10. Cricotopus larva, mentum, mandible, antenna. A. C. acornis, B. C. albitarsis, C. C. annuliventris, D. C. brevicornis.