Monatractides (Monatractides) australicus ( Cook, 1986 )

Pešić, Vladimir & Smit, Harry, 2012, Water mites of the genus Monatractides (Acari: Hydrachnidia, Torrenticolidae) from Australia, with descriptions of four new species, Zootaxa 3248, pp. 1-24 : 2-12

Monatractides (Monatractides) australicus ( Cook, 1986)

( Figs. 1–4 , 14A–D )

Torrenticola (Monatractides) australica Cook 1986: 50 .

New records. Queensland: Broken River, Eungella NP, 25.x.2005, 21º 10.069 S 148º 30.676 E 3/0/0 (1/0/0 mounted); Broken River near Conical Pool, Eungella NP, 18.ix.2000 1/1/0; Rawsons Creek, Eungella NP, 25.x.2005 9/6/0 (2/0/0 mounted); Finch Hatton Gorge Creek, downstream of Araluen Falls, Eungella NP, 25.x.2005 5/5/0; Babinda River, Wooroonooran NP, 16.x.2005, 17º 20.484 S 145º 52.113 E, 0/ 2 juvenile /0; Behana Creek, S of Gordonvale, Wooroonooran NP, 16.x.2005, 17º 10.705 S 145º 49.750 E 4/ 2juvenile /1; Double Barrel Creek, Babinda, 20.x.2005, 17º 20.852 S 145º 53.075 E 7/5/0 (3/2/0 mounted); Big Crystal Creek at Paradise Pool, Paluma Range NP, 18º 58.754 S 146º 15.231 E, alt. 48 m asl, 2/5/0 (1/0/0 mounted); Whyanbeel Creek, N of Mossman, 16º 22.205 S 145º 19.633 E, alt. 143 m asl, 15.x.2005 4/2/0 (1/0/0 mounted); West Canungra Creek at crossing with road Lamington NP-Canungra, 28º 04.400 S 153º 06.762 E, alt. 138 m asl, 17.xi.2003 1/0/0; Bundaroo Creek, Conondale NP, 03.xi.2005, 26º 41.653 S 152º 36.767 E 1/0/0; Kongaboola Creek before confluence with Carnarvon Creek, Carnarvon NP, 29.x.2005 0/1/0; Mickey Creek downstream of confluence with Warrumbah Creek, Carnarvon NP, 28.x.2005, 25° 4’51.49” S 148° 15’9.86” E, 2/4/0 (2/1/0 mounted); Hellhole Gorge, Carnarvon NP, 29.x.2005, 25° 3’24.82” S 148° 12’42.63” E, 1/2/0; Violet Creek, Carnarvon NP, 29.x.2005 1/3/0; Wards’s Canyon, upstream of Lower Aljon Falls, Carnarvon NP, 29.x.2005, 25° 2’34.75” S 148° 12’8.97” E, 1/2/0; Josephine Creek, downstream of Josephine Falls, Wooroonooran NP, 19.x.2005 0/2/0 (0/1/0 mounted); Dalrymple Creek, Goomburra Forest Reserve, 27º 58.781 S 152º 20.621 E, alt. 690 m asl, 05.xi.2005 0/1/0. New South Wales: Minnemurra River, Minnemurra Rain Forest, 34º 38.183 S 150º 43.272 E, 18.xii.2003 0/1/0; Upper Minnamurra River, W of Robertson, 06.xi.2001 1/0/0; Yarrangobilly River near Thermal Pool, Mt Kosciuszko NP, 35º 43.899 S 148º 29.091 E, alt. 910 m asl, 09.xii.2003 2/0/0; Swampy Plains River at crossing with Alpine Way, Mt Kosciuszko NP, 36º 23.121 S 148º 10.837 E, alt. 425 m asl., 9.xii.2003 15/23/0 (4/2/0 mounted); Cabbage Tree Creek at crossing with Kings Highway, 35º 34.367 S 150º 02.537 E, alt. 260 m asl, 16.xii.2003 5/0/0 (1/0/0 mounted); Never Never Rıver near Tallywood Point, 30º 21.624 S 152º 54.269 E, 23.xii.2003 2 (juvenile)/2 (1 juvenile)/0; Never Never Rıver near Tallywood Point, 30º 21.624S 152º 54.269E, 07.xi.2005 1/2/0; Sugarloaf Creek at crossing with Misty Mountain Road, Monga NP, 15.xii.2003, 35° 33’44.70” S 150° 0’48.61” E 2/4/0; Six mile Creek, South East Forest NP, 10.xii.2003 1/1/0; Nymboida River at Platypus Flat, Nymboi-Binderay NP, 30º 11.146 S 152º 41.499 E, 0/2/0; Upper Kangaroo River, N of Kangaroo Valley, 07.xi.2001 0/2/0; Tributary of Sawyers Creek, S of Kangaroo Valley, 06.xi.2001 0/1/0; Dena River at Dena River Camping Area, Dena NP, 35º 44.957 S 145º 54.961E, alt 94 m asl, 14.xii.2003 1/5(1 juvenıle)/0; Wog Wog River at crossing with Wog Way, 37º 04.986 S 149º 29.027 E, alt. 332 m asl, 10.xii.2003 1/0/0 (mounted); Bugong Creek near Morton NP, 05.xi.2001 1/0/0 (mounted); Urumbilum River, Bindarri NP, 30º 15.966 S 152º 57.042 E, alt. 137 m asl, 07.xi.2003 2/0/0; Cool Creek, 30º 26.814 S 152º 37.124 E, 22.xi.2003 0/1/0; Nulla Nulla Creek near Nulla Nulla Picnic Area, 24.xi.2003 1/1/0; Rosewood River at crossing with Little North Arm Road (near Thora), 22.ix.2003, 30º 24.133 S 152º 46.380 E 0/2/0; Carters Creek at crossing with Western Distributor Road, 16.xii.2003, 35º 30.914 S 150º 03.546 E 2/5/0. Victoria: Eurobin Creek, downstream of Mt Buffalo National Park entrance, 36º 41.745 S 146º 51.453 E, alt. 293 m asl, 10.iii.2008 1/1/0 (1/0/0 mounted); Ovens River East Branch, Harrietville, 36º 53.563 S 147º 03.965 E, alt. 516 m, 10.iii.2008 1/2/0 (0/1/0 mounted); Buckland River at Twelve Mile, 36º 51.199 S 146º 51.621 E, alt. 381 m, 10.iii.2008 1/1/0 (1/0/0 mounted); Buckland River at crossing with Buckland Valley Rd (W of Bright), 11.x.1997 0/6/0 (0/1/0 mounted).

General features. Frontal plate broad (L/W 1.6–2.3); area of primary sclerotization of the dorsal plate with four dorsoglandularia; capitular bay slender (L/W ratio 3.0–3.8); posterior suture line of Cx-4 well accentuated and directed posterolaterally; excretory pore in an identation of the line of primary sclerotization, Vgl-2 posterior to excretory pore; distal margins of P-2 and -3 without denticles, P-4 with small denticle near the insertion of the ventral hairs, P-4 ventral hairs inserted more distally; I-L-6 relatively stout (L/H ratio 2.3–2.6).

Description. Male (from Swampy Plains River, New South Wales, n = 4; in parentheses measurements of the specimens from Double Barrel Creek, Queensland, n = 3): Idiosoma (ventral view: Fig. 1B ) L 712–812 (714–756), W 505–581 (456–469); dorsal shield ( Fig. 1A ) L 588–675 (575–600), W 423–488 (394–406), L/W ratio 1.36–1.41 (1.45–1.51); dorsal plate 537–613 (531–550); shoulder plate L 175–216 (163–172), W 68–81 (59–66), L/W ratio 2.57–2.7 (2.55–2.86); frontal plate L 120–136 (117–123), W 63–78 (52–64), L/W ratio 1.74–2.0 (1.94–2.26); shoulder/frontal plate L ratio 1.43–1.59 (1.35–1.41); capitular bay L 141–150 (154–156), W 48–56 (47–50), L/W ratio 2.68–3.0 (3.1–3.28); Cx-1 total L 268–279 (267–276), Cx-1 medial L 117–134 (113–121), Cx-2+3 medial 70–84 (73–82); ratio Cx-1 L/Cx-2+3 medial L 3.2–3.9 (3.37–3.78); Cx-1 medial L/Cx-2+3 medial L 1.39–1.86 (1.45–1.63); genital field L/W 128–151 (139–144)/113–128 (115–119), L/W ratio 1.13–1.18 (1.19–1.21); ejaculatory complex ( Fig. 1E ) normal in shape, L 177–190 (178–206); distance genital field–excretory pore 150–216 (166–191), genital field–caudal idiosoma margin 239–294 (220–245); capitulum ( Fig. 1F ) ventral L 164–185 (178–186); chelicera total L 200–220 (211–214); palp ( Figs. 1G–H ): total L 172–187 (180–181), dL: P-1, 26–28 (26–28); P-2, 50–55 (53–55); P-3, 33–39 (35–37); P-4, 46–51 (46–47); P-5, 16–18 (16–17); P-2/P-4 ratio 1.06– 1.13 (1.15–1.17); L I-4-6 ( Fig. 1D ): 92–104 (93–97), 95–111 (99–103), 100–110 (103–106); I-L-6 L/H ratio 2.46– 2.6 (2.44–2.46).

Female (from Swampy Plains River, New South Wales, n = 2; in parentheses measurements of the specimens from Double Barrel Creek, Queensland, n = 2): Idiosoma (ventral view: Fig. 2B ) L 900–903 (772–800), W 613– 628 (504–513); dorsal shield ( Fig. 2A ) L 738–744 (627–644), W 519–538 (431–434), L/W ratio 1.39–1.43 (1.44– 1.49); dorsal plate 666–681 (581–600); shoulder plate L 212–219 (169–184), W 84–89 (58–63), L/W ratio 2.44– 2.56 (2.72–3.12); frontal plate L 141–143 (116–125), W 78–87 (58–59), L/W ratio 1.64–1.81 (2.0–2.16); shoulder/ frontal plate L ratio 1.48–1.55 (1.38–1.59); capitular bay L 172–177 (161–167), W 53 (50–53), L/W ratio 3.25 (3.03–3.3); Cx-1 total L 300–306 (283–284), Cx-1 medial L 128–130 (119–122), Cx-2+3 medial 53–62 (59–63); ratio Cx-1 L/Cx-2+3 medial L 4.8–5.8 (4.5–4.8); Cx-1 medial L/Cx-2+3 medial L 2.06–2.45 (1.89–2.07); genital field L/W 188 (166)/167–184 (153–156), L/W ratio 1.02–1.13 (1.06–1.09); distance genital field–excretory pore 219–228 (166–191), genital field–caudal idiosoma margin 338–339 (263–278); capitulum ventral L 202–204 (192–195); chelicera total L 234–235 (223–226); palp ( Fig. 2D ): total L 207–208 (191), dL: P-1, 30–31 (29); P-2, 61–62 (56–57); P-3, 42–43 (39); P-4, 54–55 (47–49); P-5, 19 (17); P-2/P-4 ratio 1.1–1.13 (1.16–1.19); L I-4-6: 112–114 (99–100), 114–115 (106–108), 114–115 (103–109); I-L-6 L/H ratio 2.47–2.58 (2.46–2.5).

In addition we give measurements of the male and female from Mickey Creek downstream of confluence with Warrumbah Creek, Queensland (general differences see below in the “remarks”-section).

Male (n = 2): Idiosoma (ventral view: Fig. 4B ) L 763–784, W 572–625; dorsal shield ( Fig. 4A ) L 625–631, W 488–538, L/W ratio 1.17–1.28; dorsal plate 569–572; shoulder plate L 188–192, W 73–81, L/W ratio 2.36–2.63; frontal plate L 128–141, W 69–75, L/W ratio 1.7–2.0; shoulder/frontal plate L ratio 1.36–1.49; capitular bay L 159–170, W 48–49, L/W ratio 3.3–3.5; Cx-1 total L 281–291, Cx-1 medial L 120–22, Cx-2+3 medial 67–78; ratio Cx-1 L/Cx-2+3 medial L 3.7–4.2; Cx-1 medial L/Cx-2+3 medial L 1.54–1.82; genital field L/W 144–148/125– 132, L/W ratio 1.12–1.15; ejaculatory complex L 178–198; distance genital field–excretory pore 141–172, genital field–caudal idiosoma margin 238–282; capitulum ventral L 182–206; chelicera total L 222–229; palp: total L 184–196, dL: P-1, 28–31; P-2, 55–60; P-3, 37–38; P-4, 48–50; P-5, 16–17; P-2/P-4 ratio 1.15–1.2; L I-4-6: 100– 105, 102–105, 99–100; I-L-6 L/H ratio 2.42.

Female (n = 1): Idiosoma (ventral view: Fig. 4D ) L 963, W 772; dorsal shield ( Fig. 4C ) L 809, W 644, L/W ratio 1.26; dorsal plate 738; shoulder plate L 247–249, W 94–98, L/W ratio 2.54–2.63; frontal plate L 147–153, W 89–94, L/W ratio 1.56–1.72; shoulder/frontal plate L ratio 1.61–1.69; capitular bay L 188, W 50, L/W ratio 3.7; Cx-1 total L 322, Cx-1 medial L 136, Cx-2+3 medial 70; ratio Cx-1 L/Cx-2+3 medial L 4.6; Cx-1 medial L/Cx-2+3 medial L 1.94; genital field L/W 197/186, L/W ratio 1.06; distance genital field–excretory pore 200, genital field– caudal idiosoma margin 356; capitulum ventral L 223; chelicera total L 257; palp: total L 218, dL: P-1, 34; P-2, 65; P-3, 44; P-4, 56; P-5, 19; P-2/P-4 ratio 1.16; L I-4-6: 114, 119, 109; I-L-6 L/H ratio 2.42.

Remarks. Monatractides australicus belongs to the M. macroporus ( K. Viets, 1935) species-complex (see: Pešiċ & Smit 2009). In the original description Cook (1986) compared M. australicus with M. macrognathus (Java, Indonesia) and mentioned that the latter species differs in the shoulder plates noticeably bulging anteriorly and a proportionally much longer genital field in the male. Further, M. australicus has four dorsoglandularia on the area of primary sclerotization of the dorsal plate, while M. macrognathus has only two (see: Pešiċ & Smit 2009). Due to the latter character, M. australicus resembles M. major ( K. Viets, 1935) , a species originally described as a "forma" of M. macrognathus , but later raised to species level by Wiles (1991). M. australicus can be distinguished from M. major (see K. Viets 1935), in having broader frontal plates and a less elongated genital field.

Cook (1986) described M. australicus based on the holotype male and two paratype males from New South Wales (Tuntable Creek near falls, north of Nimbin) and one male paratype from Queensland (Cattle Creek somewhat W of Gargett, W of Mackay). This is the first description of the female.

The specimens examined from Australia fit the description of M. australicus . However, we found considerable variability in the colour pattern and in the idiosoma and gnathosoma measurements of the populations from different parts of its distribution area. In the original description, Cook (1986) mentioned that a colour pattern is absent. The specimens examined from New South Wales and Victoria ( Fig. 14C ) match this description, but specimens from Queensland have a characteristic colour pattern on the dorsal shield as shown in Figs. 14A–B . The populations from Big Crystal Creek and Whyanbeel Creek have a colour pattern on the ventral shield as illustrated in Fig. 14D . Populations of M. australicus from Queensland differ from populations from the southern part of its distribution area (New South Wales and Victoria) in generally minor idiosoma and gnathosoma dimensions, a slightly more elongated idiosoma, less broader frontal plates and a relatively shorter postgenital area ( Figs. 3A–D ; Table 1 ). However, in some populations from Queensland and New South Wales an overlap was found in these measurements (see Tables 1–2 ). In all other important diagnostic features the examined specimens are in good agreement with the description of Cook (1986).

The populations from Carnarvon National Park differ from typical M. australicus populations in the more roundish idiosoma shape ( Figs. 4A–D ). The fact that these populations are from a lowland area separated by Great Dividing range from the other M. australicus populations, may suggest that there is some degree of genetic isolation. However, understanding of these populations is not possible without the application of molecular genetic techniques.

Malformations. In one female (from Josephine Creek, Qld), fused frontal plates were observed ( Fig. 2E ).

Distribution. Widespread in Australia; known from Queensland, New South Wales and Victoria.

Monatractides (Monatractides) kotooma ( Cook, 1986) 1 ( Figs. 5A–F )

Torrenticola (Monatractides) kotooma Cook, 1986: 49 .

New record. Queensland: Emmagen Creek, Daintree NP, 02.ix.2000 1/0/0 (mounted).

General features (based on our specimen and original description, Cook 1986). Frontal plate slender (L/W> 2.5); idiosoma elongated (dorsal shield L/W> 1.5); capitular bay relatively wide (L/W ratio 2.6); posterior suture line of Cx-4 well accentuated and directed posterolaterally; excretory pore on the line of primary sclerotization, Vgl-2 posterior to the excretory pore; distal margins of P-2 and -3 without denticles, P-4 with well developed denticle near the insertion of the ventral hairs, I-L-6 relatively stout (L/H ratio 2.8).

Description. Male: Idiosoma (ventral view: Fig. 5B ) L 738, W 491; dorsal shield ( Fig. 5A ) L 619, W 400, L/ W ratio 1.55; dorsal plate 581; shoulder plate L 164–172, W 56–58, L/W ratio 2.9–3.0; frontal plate L 122–127, W 47, L/W ratio 2.6–2.7; shoulder/frontal plate L ratio 1.29–1.41; colour pattern absent; capitular bay L 152, W 59, L/ W ratio 2.58; Cx-1 total L 269, Cx-1 medial L 117, Cx-2+3 medial 56; ratio Cx-1 L/Cx-2+3 medial L 4.8; Cx-1 medial L/Cx-2+3 medial L 2.1; genital field L/W 138/125, L/W ratio 1.1; ejaculatory complex normal in shape, L 188; distance genital field–excretory pore 209, genital field–caudal idiosoma margin 259; capitulum ( Fig. 5D ) ven-

1. The name kotooma is an arbitrary combination of letters (Cook in litt.), and is therefore considered by us as a noun in apposition. According to article 34.2.1 of the International Code of Zoological Nomenclature the name must not be changed to agree in gender with the generic name.

tral L 182; chelicera total L 215; palp ( Figs. 5E–F ): total L 194, dL: P-1, 27; P-2, 62; P-3, 35; P-4, 52; P-5, 18; P-2/ P-4 ratio 1.19; L I-4-6 ( Fig. 5C ): 106, 115, 112; I-L-6 L/H 2.8.

Remarks. The single male specimen examined from Emmagen Creek fits the description of M. kotooma which was based on one male and one female specimen from Babinda Creek at Babinda, Queensland ( Cook 1986). This species belongs to the M. luteus ( K. Viets, 1935) species-complex, characterized by the presence of anteriorly broad and shorter Cx-1, a relatively wide capitular bay, a relatively short medial suture line of Cx-2+ 3 in both sexes and I-L-6 not greatly expanded ( Pešiċ & Smit 2010). Due to the elongated idiosoma (e.g., dorsal shield L/W> 1.5) and the shape of the capitular bay which is more rounded at its proximal end, Monatractides kotooma most closely resembles M. nipsanicus Pešiċ & Smit, 2011 , known from a single male from New Guinea. The new species differs in minor idiosoma and gnathosoma dimensions and a less elongated genital field (see Pešiċ & Smit 2011). Furthermore, M. kotooma is characterized by having relatively narrower frontal platelets.

Distribution. Australia: Queensland ( Cook 1986, present study).

Figures

FIGURE 1 A – H. Monatractides australicus (Cook, 1986), male, Swampy Plain River (NSW): A = dorsal shield; B = ventral shield; C = anterodorsal portion of ventral shield; D = I-L- 4 – 6; E = ejaculatory complex; F = capitulum and chelicera; G = palp, medial view; H = palp, lateral view. Scale bars = 100 μm.

FIGURE 2 A – E. Monatractides australicus (Cook, 1986), female (A – D = specimen from Swampy Plain River, NSW; E = specimen from Josephine Creek, Qld): A, E = dorsal shield; B = ventral shield; C = anterodorsal portion of ventral shield; D = palp, medial view (P- 1 missing). Scale bars = 100 μm.

FIGURE 3 A – D. Monatractides australicus (Cook, 1986), Double Barrel Creek (Qld) (A – B = male, C – D = female): A, C = dorsal shield; B, D = ventral shield. Scale bar = 100 μm.

FIGURE 4 A – D. Monatractides australicus (Cook, 1986), Mickey Creek, Carnarvon NP (Qld) (A – B = male, C – D = female): A, C = dorsal shield; B, D = ventral shield. Scale bar = 100 μm.

FIGURE 14 A – I. Photographs of dorsal and ventral shields. A – D Monatractides australicus (Cook, 1986): A—specimen from Double Barrel Creek, Qld (male, dorsal shield), B—specimen from Double Barrel Creek, Qld (female, dorsal shield), C - specimen from Swampy Plain River, NSW (female, dorsal shield), D—specimen from Big Crystal Crek, Qld (male, ventral shield); E – F, H Monatractides polypapillatus sp. nov.: E—specimen from Double Barrel Creek, Qld (male, dorsal shield), F—specimen from Big Crystal Creek, Qld (male, ventral shield), H—specimen from Double Barrel Creek, Qld (female, dorsal shield). G Monatractides ironicus sp. nov.: specimen from Gordon Creek (Qld) (male, dorsal shield). I Monatractides harveyi sp. nov.: specimen from Barramundie Creek (NT) (male, dorsal shield).

FIGURE 5 A – F. Monatractides kotooma (Cook, 1986), male, Emmagen Creek (Qld): A = dorsal shield; B = ventral shield; C = I-L- 4 - 6; D = capitulum; E = palp, lateral view; F = palp, medial view. Scale bars = 100 μm.

Tables

TABLE 1. Measurements of Monatractides australicus from New South Wales (Tuntable Creek, Wog Wog River, Cabbage Tree Creek and Bugong Creek) and Victoria (Eurobin Creek and Buckland River).

Idiosoma L Idiosoma W Idiosoma L/W Ds L Ds L	Holotype 3 Wog Wog Tuntable River, 13 Creek (from Cook, 1986) 851 805 608 594 1.4 1.35 677 672 536 491	Cabbage Tree Bugong Creek, 13 Creek, 13 781 715 588 550 1.33 1.3 634 600 488 463	Eurobin Creek, 13 756 538 1.41 631 444	Buckland River, 13 763 544 1.4 638 463
Ds L/W Dp L Sh plate L	1.26 1.37 - 600 200 213–216	1.3 1.3 587 543 194–197 197–203	1.42 474 200	1.38 583 198–191
Sh plate W Sh plate L/W	81 83–86 2.47 2.48–2.6	80–81 78–84 2.4–2.46 2.5–2.53	77–78 2.56–2.6	72 2.65–2.75
F plate L F plate W F plate L/W	133 138 76 84 1.75 1.64	135–141 128–134 68–72 69–75 2.0 1.79–1.86	129–131 72 1.79–1.82	130–133 64–66 2.02–2.03
Sh pl L/f pl L Capitular bay L	1.5 1.54–1.56 162 161	1.38–1.46 1.54–1.56 158 141	1.53–1.55 150	1.44–1.52 145
Capitular bay W Cb L/W Cx-1 L	48 50 3.38 3.22 - 299	50 48 3.16 2.94 294 266	50 3.0 278	52 2.8 273
Cx-1 mL Cx-2+3 mL Cx-1 L/Cx-2+3 mL Cx-1 mL/Cx-2+3 mL Genital field L Genital field W Gf L/W Dist gf—expo	- 137 - 72 - 4.15 - 1.9 152 156 131 132 1.16 1.18 - 198	135 125 69 67 4.26 4.0 1.96 1.87 148 133 134 125 1.1 1.06 178 193	127 72 3.9 1.76 152 138 1.1 192	128 79 3.46 1.62 145 126 1.15 186
Dist gf—cauda	- 269	256 252	247	266
Ec L	- 185	203 172	194	178
Capitulum vL Chelicera L Palp, total L P-1 dL P-2 dL	211 189 229 228 193 201 25 27 55 59	187 174 212 205 190 183 27 26 55 53	185 - 189 27 55	178 206 187 29 54
P-3 dL P-4 dL P-5 dL dL P-2/P-4	40 42 52 54 21 19 1.06 1.09	37 38 54 49 17 17 1.02 1.08	39 49 19 1.12	37 50 17 1.08
I-L-4 L I-L-5 L I-L-6 L	107 103 111 109 111 114	103 97 106 100 111 106	102 106 112	99 102 104
I-L-6 L/H	- 2.47	2.48 2.34		2.54