Cricotopus brevicornis 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 : 10-11

publication ID	https://doi.org/ 10.11646/zootaxa.3919.1.1
publication LSID	lsid:zoobank.org:pub:218630EE-6BF7-4E35-A8F6-9E8260D60FA0
DOI	https://doi.org/10.5281/zenodo.6122636
persistent identifier	https://treatment.plazi.org/id/1E863B19-6613-4C91-8861-F867AE4BF8DE
taxon LSID	lsid:zoobank.org:act:1E863B19-6613-4C91-8861-F867AE4BF8DE
treatment provided by	Plazi
scientific name	Cricotopus brevicornis Drayson & Cranston
status	sp. nov.

Treatment

Cricotopus brevicornis Drayson & Cranston View in CoL sp. n.

( Figs. 1 View FIGURE 1 D, 2D, 4D, 5H, 6C, 7E, 8D, 10D)

urn:lsid:zoobank.org: act :1E863B19-6613-4C91-8861-F867AE4BF8 DE

Cricotopus View in CoL ‘sp. II’ Drayson, 1992: 58

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

Type material. Holotype: P♂, AUSTRALIA: NSW, Albury, Murray R., Waterworks, 36°07'S 146°54'E, 21.xi.1989 (Cook)( ANIC). Paratypes: Qld.: 18 Pe, Carnarvon NP, Carnarvon Ck., 25°04'S 148°14'E., 4/ 5.vii.1991 (Black); 4 Pe, Conondale Range, Stony Ck. #2, 26°52'S 152°44'E, 24.v.1990 (Cranston). NSW: Pe, S.E. Araluen, Deua R., 35°45'S 149° 57'E, 29.iii.1988 (Cranston); Le/Pe/♀, Albury, Murray R., Noreuil Park, 36°05'S 146°56'E, 22.xii. l989 (Cook), Le/Pe/♀, same except 9.iv.1990; 2 Pe, Albury, Murray R. Stn 6, 36°06'S 147°01'E, 17.v.1989 (Cook); ♂, 23 Pe, Albury, Murray R., Waterworks, 36°07'S 146°54'E, 21.xi.1989 (Cook). Vic: 6 Pe, Albury, Middle Ck., Kiewa Valley Highway, 36°10'S 146°56'E, 26.ii.1990 (Cook); 4 Pe, Albury, Middle Ck., Street's Rd, 36°11'S 146°56'E, 26.ii.1990 (Cook); 8 Pe, Albury, Middle Ck., Beechworth Rd, 36°15'S 146°50'E, 26.ii.1990 (Cook). NT: Pe, Kakadu NP, South Alligator R., Gimbat, Coronation Hill, 13°34'S 132°35'E, 24.v.1988 (Cranston); 2 Pe, Kakadu NP, South Alligator R., Coronation Hill, 13°35'S 132°36'E, 4/ 5.vi.1988 (Cranston); Pe, Kakadu NP, Koolpin Ck., 13°35'S 132°36'E, 4/ 5.vi.1988 (Cranston).

Other material examined. Qld.: P♂, Mt. Lewis, trib. Churchill Ck., 16°34'S 145°20'E, 6-7.iv.1997 (Cranston), same except Pe, Davies Ck., above falls, 17°01'S 145°35'E, 11–12.iv.1997 (Cranston); 2L, many Pe, P♂, P♀, nr. Proserpine, Brandy Ck., 21–23.iii.1998 (Cranston); 7Pe, Bartle Frere, Junction Ck., 17°16'S 146°55'E, 17–18.iv.1997 (Cranston); Pe, Lawn Hill NP, Indarri Falls, 18°42'S 138°29'E, 16.v.1995 (Cranston). Western Australia, Pe, N.W. Coastal Hwy, Sherlock R., 20°57'S 117°36'E (Cranston); 2Pe, Millstream Chichester NP, Fortescue R., below homestead, 21°33'S 117°03'E, 24–25.iv.1992 (Cranston); 6Pe, Chinderwarrinder Pool, 21°35'S 117°04'E, 25.iv.1992 (Cranston). NT: 2Pe, Kakadu NP, South Alligator R., Fisher Ck., 13°33'S 132°33'E, 24.v.1988 (Cranston); 6L, Pe, ♂, P♂, Kapalga, 12°36'S 132°25'E, 16.xii.1993 (Douglas).

Molecular material. Qld: L, Finch Hatton Gorge NP, Rawson’s R., 21°04'S 148°38'E, 15.ix. 2008, 736 m asl (Krosch) (Mv-RAW3); 2♂, L, Andy Williams Pk., Cedar Creek Rd, Cedar Ck, 27°19'S 152°48'E, 21.iii. 2013, 143 m asl (Krosch) (Mv-CedP1, 2, Ced12); L, Bunya, n. Brisbane, Carter Court, South Pine R., 27°21'S 152°56'E, 21.iii.2013, 22 m asl (Krosch) (Mv-SPR17); 5L, Dayboro, n. Brisbane, Lee’s Crossing Rd, North Pine R., 27°12'S 152°48'E, 27.ii.2014, 64 m asl (Krosch) (Mv-NPR1.2, 1.4, 1.6, 1.9, 1.13); L, Arana Hills, Dawson Parade, Kedron Brook, 27°24'S 152°58'E, 27.ii.2014, 42 m asl (Krosch) (Mv-KBR2.4); 2L, Numinbah Valley, Nerang R., 28°7'S 153°14'E, 20.v. 2013, 120 m asl (Krosch) (Mv-Ner1, 2); L, Mt Barney NP, Seidenspinner Rd, Mt Barney Ck., 28°14'S 152°44'E, 21.iii. 2013, 176 m asl (Krosch) (Mv-MtBy8); L, Currumbin Valley, Currumbin Ck., 28°13'S 153°22'E, 20.v.2013, 88 m asl (Krosch). NSW, L, Capertee, Glen Davis Rd., Capertee R., 20.i.2013 (( Cranston) (Mv-NSW17.3.1). NT: 2L, Kakadu NP, Kambolgie Ck., 13°30'S 132°25'E, 30–31.vii.2013 (Cranston & Krosch) (Mv-NT14.5.1, 2).

Description. MALE ( Figs. 1 View FIGURE 1 D, 2D) n = 3 (pharate). 2.5–2.7 mm.

Head. Ant 725–880 µm; Fl 1–12 340–416 µm, Fl 13 375–472 µm; A.R. 0.9–1.1. Palp 275 µm. 1 Fr, 5 Po, Clyp moderately setose.

Thorax. All sclerites mid-brown. Laps 2–3, Ac 7–9, Dc 19, Pa 3, Scts 6.

Wings. Unmeasurable. Sq 5.

Legs. Unmeasurable.

Abdomen. TI pale, TII mid-brown with pale anterior band, TIII–IV mid-brown with pale anterior and posterior bands, other tergites mid-brown.

Hypopygium ( Fig. 2 View FIGURE 2 D). Gcx 128–162 µm, iv elongate, pointed and curved posteriorly. Gst 48–70 µm, about 2/ 5 (0.41) Gcx, all microtrichiose, blunt apically; crista dorsalis absent.

FEMALE (n=2) 1.9 mm.

Head. Ant 269 µm. Palp 310 µm. 2 Co, 2 Fs

Thorax. Uniform mid-brown. Laps 3, Ac 9–12, Dc 12–15, Pa 3–5, Scts 6–8.

Wings. 1.2–1.3 mm. Anal lobe weakly produced. Sq 1, R 1–2, R4+5 1–2.

Legs. Femora on all legs mid-brown; tibiae on all legs very pale, apically mid-brown; tarsomeres of foreleg basally pale, apically mid-brown, tarsomeres of mid- and hind leg white.

Abdomen. Brown.

Genitalia. Spermathecae comprising mid-brown, ovoid capsules and recurved ducts ( Fig. 4 View FIGURE 4 D).

PUPA. 2.6–4.3 mm, very pale brown.

Cephalothorax. Slightly rugose. Th 64–100 µm; hyaline, short, apically pointed, with pointed scales especially distally ( Figs. 6 View FIGURE 6 C, 7E). Fs (30–80 µm), on prefrons.

Abdomen ( Fig. 8 View FIGURE 8 D). PSB on II and sometimes much reduced on III. PSA distinct also on SVII. Hook row on TII usually less than half width of segment (0.38–0.53). One, sometimes two small sparse spinule fields anterior to hook row on TII. D4 seta on TIII clearly darker, longer and stouter than D4 seta on TII and IV. Ms 110–160 µm, about 1/20 (0.04–0.07) length of abdomen.

4TH INSTAR LARVA ( Fig. 10 View FIGURE 10 D) (n=5). 3.7 mm. H.l. 375–515 µm, very pale yellow-brown with darker apical mandible, mentum and occipital margin; abdomen blue; procercus hyaline with mid-brown-black patch. Anterior and posterior parapods yellow.

Head. Ant 68–77 µm, 1st, 38–45 µm, 2–5 26–33 µm; A.R. 1.25–1.5. Md 125–150 µm, with smooth inner and outer margin, pale to mid-brown with distal 1/3 darker. Mentum 105–112 µm, pale brown posteriorly, mid-to dark brown anteriorly: 6 pairs laterals, evenly decreasing on slope.

Abdomen. L4 plumose on segments A2–A6. Pc 15 µm, A.s. 500 µm.

Etymology. The epithet brevicornis derives from early recognition of the short (brevi-) thoracic horn (- cornis). This is no longer a discriminatory feature but the name is retained.

Remarks. Adults of C. brevicornis sp.n. can be recognised by the unique colour pattern of the abdomen ( Fig. 1 View FIGURE 1 D). Pupae have frontal setae on the prefrons, weak pattern on TII, no paratergal spinules, and stout D4 seta on TIII. Larvae can be recognised by the mandible uniquely amongst Australian Cricotopus being smooth on both inner and outer margins, and with small Lauterborn organs and 2nd antennal segment subequal to combined 3rd and 4th segments. These features however are shared with larvae of two or more Australian members of the genus Paratrichocladius . From ‘M1/FNQ1’ brevicornis is separated by the normal-length apical mandibular tooth, but separation from a taxon Paratrichocladius ‘SW QLD’ is very difficult, and features used in the key may not hold up (see Comments below).

C. brevicornis is widespread in warmer parts of Australia, absent from Tasmania and present in Victoria only in the north-east on the Murray River. The species tolerates elevated temperatures and nutrient levels, in both larger rivers and creeks.