Table Of ContentRecords of the Western Australian Museum 18: 233-261 (1997).
Australian water mites of the genus Arrenurus, with the description of
twelve new species from northern and western Australia
(Acari: Hydrachnellae: Arrenuridae)
Harry Smit
Emmastraat 43-a, 1814 DM Alkmaar, The Netherlands
Abstract - Two new subgenera of the genus Arrenurus, viz., Dividuracarus
(type species Arrenurus (Dividuracarus) tripartitus sp. nov.) and
Brevicaudaturus (type species Arrenurus lohmanni Piersig, 1898), and 12 new
species, viz., A. (A.) ensifer, A. (A.) harveyi, A. (A.) Uliaceus, A. (A.)
manlonensis, A. (Dividuracarus) gereckei, A. (Dividuracarus) tripartitus, A.
(Megaluracarus) caeruleus, A. (Megaluracarus) gilvus, A. (Micruracarus)
anbangbang, A. (Micruracarus) jabiruensis, A. (Micruracarus) purpureus and A.
(Micruracarus) separatus are described from Northern Territory and Western
Australia. Further, a description is provided for the females of A.
(Brevicaudaturus) lohmanni Piersig, A. (A.) balladoniensis Halik and A.
(Megaluracarus) vanderpalae Smit, while a more detailed description is given
for A. (Megaluracarus) thienemanni K.O. Viets. In addition, three species are
reported new for the fauna of Australia. A key is given for the Australian
species of the genus Arrenurus.
INTRODUCTION Zoological Museum of the University of
Two genera of the water mite family Arrenuridae Amsterdam (ZMA).
have been reported from Australia, Wuria and The following abbreviations have been used (see
Arrenurus. Although the genus Arrenurus has a Figure 9): Ll-4 lateroglandularia 1-4; Al-2 pre-
cosmopolitan distribution and is one of the most and post-antennal glandularia; Dl-4
species-rich in the water mites, not more than 20 dorsoglandularia 1—4; CXI—4 coxal plates 1-4; PI-
species and subspecies have been reported from PV palp segments 1-5; l.p. ligulate process; SMF -
Australia (see Table 1). These species belong to the Forschungsinstitut und Naturmuseum
subgenera Arrenurus, Megaluracarus, Micruracarus Senckenberg. All measurements are in pm,
and Truncaturus. Only one species of Wuria, W. measurements of leg and palp segments are of the
boutit, is known (Harvey 1989). dorsal margins. Measurements of paratypes in the
On a trip through the Northern Territory and description of new species are given in brackets.
Western Australia, areas seldom visited by Unless otherwise stated, all species have the
acarologists, I collected 15 Arrenurus species new second, third and fourth legs with numerous
for the fauna of Australia, of which 12 species are swimming setae
new to science. Further, two new subgenera of this
genus are described. A number of females of
previously known species are described for the SYSTEMATICS
first time, and three species new to the Australian
Arrenurus (Arrenurus) balladoniensis Halfk
fauna are reported, i.e. Arrenurus gracilipes Piersig,
Figures 1-2
A. lohmanni Piersig and A. rouxi Walter.
Separate keys are given for the males and Arrenurus balladoniensis Halik, 1940: 283; Halik,
females of the Australian members of the genus 1941: 106; Cook, 1986: 305; Smit, 1992: 106.
Arrenurus.
Arrenurus Cjuadripapillatus Lundblad, 1941: 120;
All materia! has been collected by the author.
Lundblad, 1947: 74.
Western Australia and Northern Territory
holotypes and paratypes have been deposited in Material Examined
the Western Australian Museum (Perth) (WAM), Australia: Northern Territory: 13 6,13 $, ponds
and in Northern Territory Museum (Darwin) in Ormiston Creek, Ormiston National Park, 6
(NTM) respectively. Further, paratypes and almost August 1994 (ZMA). Western Australia: 2 6, 2 9,
all non-type material have been deposited in the Lake Monger, Perth, 26 August 1994 (ZMA).
234 H. Smit
Description Park, Western Australia, Australia, 13 August 1994
(WAM).
Female
Body 1944 (1848-2232) long and 1656 (1656-1932)
Paratypes
wide. Body colour yellow. Anterior body margin
Australia: Western Australia: 1 S (not fully
slightly concave. Posterolateral comers of body
sclerotized) (ZMA), 1 2 (WAM) and 1 nymph (?)
absent. Dorsal shield slender (Figure 2), rounded
(ZMA), Ashburton River at crossing with North
anteriorly, truncated posteriorly; dorsal shield 1272
West Coastal Highway, 18 August 1994.
long and 708 wide. Capitular bay V-shaped.
Distance of CX4 about two times width of one
genital valve. Medial margin of CX3 and CX4 of Diagnosis
equal length. Gonopore 175 long. Genital valves Petiole sword-like, dorsal shield of male
with small chitinous patches. Genital plates truncated. Dorsal shield of female slender, D1 and
straight and narrow, sloping posteriorly, slightly L4 on humps.
widened laterally (Figure 1). Lengths of PI-PV: 55,
137, 115,156, 92; PII with two setae on medial side.
Description
Lengths of I-leg-4-6: 243, 223, 223. Lengths of IV-
leg-4-6 310, 291, 252.
Male
Body 1280 long (including petiole) and 1038
Remarks
wide. Body colour yellowish. Anterior body
A widespread species in Australia, known from margin concave. Dorsal shield 713 long and 446
Western Australia, Victoria and Queensland. Only wide, tapering posteriorly, truncated (Figure 3). D1
the male of this species was known hitherto, a on large humps (Figure 5). Cauda short, almost
description of the female is given above. absent. Pygal lobes well developed, broad and
The shape of the dorsal shield of the female is rounded. Hyaline membrane large. Gonopore 68
similar to that of A. fissipetiolatus Lundblad and A. long. Genital plates not extending to lateral body
ensifer sp. nov.
margin, widened medially (Figure 4). Petiole
sword-like, 232 long (measured from ventral view).
Ligulate process absent. Curved setae extending to
Arrenurus (Arretturus) ensifer sp. nov.
posterior margin of petiole. Lengths of PI-PV: 43,
Figures 3-8
130, 108, 130, 86; PII with 2 heavy setae on medial
Materia] Examined side near anterior margin of segment; P1V with an
angular anteroventral comer. Paratype male with 4
Holotype setae on medial side of PII, of which 2 near
6, pool, Joffre Gorge, Hamersley Range National anteroventral comer of segment. Lengths of I-leg-
Australian Arrenurus 235
Figures 3-8 Arrenurus (Arrenurus) ensifer sp. nov., holotype S (unless stated otherwise): 3, ventral view; 4, dorsal
view; 5, lateral view; paratype 2; 6, ventral view; 7, dorsal view; 8, palp. Scale lines, 50 pm (Figure 8),
200 pm (Figures 3-6), 500 pm (Figure 7).
236 H. Smit
Figures 9-14 Arrenurus (Arrenurus) harveyi sp. nov., holotype 6 (unless stated otherwise): 9, dorsal view (for
explanation of abbreviations see introduction); 10, detail of petiole; 11, ventral view; 12, lateral view; 13,
palp; 14, ventral view, paratype ?. Scale lines, 50 pm (Figure 10, 13), 200 pm (Figures 9, 11,12, 14).
Australian Arrenurus 237
4-6: 223, 204, 213. Lengths of IV-leg-4-6: 296, 175, pygal lobes well developed (Figure 9). Dorsal
194; IV-leg-4 with a short spur. shield incomplete, anterior part more or less
triangular. D1 on small hump; D3 on large fused,
Female obtuse hump (Figure 12). Gonopore 49 long.
Body 1416 long and 1296 wide. Anterior and Genital plates narrow and long, extending onto
posterior body margin concave. D1 and L4 on lateral sides of body (Figure 11). Hyaline
humps. Dorsal shield slender, rounded anteriorly membrane well developed, trapezoid, posterior
and truncated posteriorly (Figure 7). Medial margin concave. Petiole 146 long (measured from
margin of CX4 longer than medial margin of CX3. ventral view), extending beyond pygal lobes,
Distance of CX4 larger than one genital valve. rounded posteriorly. Ligulate process reversed
Gonopore 145 long, genital valves with small mushroom-shaped (Figure 10). Curved setae
chitinous patches. Genital plates narrow and short, extending to posterior margin of petiole. Lengths
slightly bowed (Figure 6). Excretory pore of PI-PV: 36, 77, 60, 96, 58; PII with 4 seta on
surrounded by a large sclerotization. Lengths of medial side, of which 2 setae in anteroventral
PI-PV: 48, 113, 98, 124, 82; palp as in male, but PII comer (Figure 13). Lengths of I-leg-4-6: 155, 146,
has in anteroventral comer two large and one small 204; lengths of IV-leg-4-6: 286, 107, 146; IV-leg-4
seta (Figure 8). Lengths of I-leg-4-6: 213, 204, 204; with a spur.
lengths of IV-leg-4-6: 272, 233, 243.
Female
Remarks Body 1038 long and 825 wide. Anterior body
The female of the new species has a similar margin rounded. Posterolateral corners very
dorsal shield as A. balladoniensis, but is smaller, distinct. L3 on small humps. Gonopore 87 long;
with distinct humps on the dorsum. Males of the genital valves with small, rounded chitinous
two species differ in the shape of the petiole. The patches; anterior and posterior patch connected by
shape of the petiole separates the male from other a small strip. Genital fields straight and narrow,
species. slightly sloping, laterally rounded (Figure 14).
Length of PI-PV: 29, 67, 50, 88, 49. PII with 2 setae
Etymology on medial side, of which one seta located
The species is named after the sword-like petiole. anteroventrally. Length of I-leg-4-6: 87, 68, 145.;
length of IV-leg-4-6 175, 145,136.
Arrenurus (Arrenurus) harveyi sp. nov. Remarks
Figures 9-14 The assignment of the female is somewhat
uncertain, as two different Arrenurus species
Material Examined
Holotype Table 1. Previously reported Arrenurus species from
S, Chinderwariner Pool, Millstream-Chichester Australia (compiled from Cook 1986; K.O.
National Park, Western Australia, Australia, 15 Viets 1975; K.O. Viets 1981; Smit 1992; Smith
August 1994 (WAM). and Harvey 1989).
Arrenurus (Arrenurus) nuslralicus Lundblad 1941
Paratypes A. (Arrenurus) balladoniensis Halfk 1940
Australia: Western Australia: 2 d (ZMA), 1 9 A. (Arrenurus) fissipetiolatus Lundblad 1947
(WAM), same data as holotype. A. (Arrenurus) pseudoaffinis Piersig 1906
A. (Megaluracarus) cheetus Cook 1986
Diagnosis A. (Megaluracarus) harpagopalpus Walter 1929
A. (Megaluracarus) margatellus Cook 1986
Petiole of rounded shape, ligulate process
A. (Megaluracarus) olodus Cook 1986
reversed mushroom-shaped. Female with distinct
A. (Megaluracarus) roobeeki Smit 1992
posterolateral comers of the body; genital plates
A. (Megaluracarus) restrains Daday 1898
straight and narrow, slightly sloping; genital valves A. (Megaluracarus) rostratus degeneratus K.O. Viets 1984
with small, rounded chitinous patches, connected A. (Megaluracarus) thienemanni K.O. Viets 1984
by a small strip. A. (Megaluracarus) tricornutus K. Viets 1955
A. (Megaluracarus) vanderpalae Smit 1992
Description A. (Megaluracarus) victorianus K.O. Viets 1978
A. (Micruracarus) forpicatoides Lundblad 1941
Male A. (?Micruracarus) kitchingi Smith and Harvey 1989
Body 1154 (1096-1135) long (including petiole) A. (Truncaturus) haswelli Cook 1986
and 766 (732-745) wide. Body colour blueish. A. (Truncaturus) novaehoUandiae Lundblad 1947
Anterior margin of body concave. Cauda and A. (Truncaturus) tasmanicus Lundblad 1941
238 H. Smit
Figures 15-19 Arrenurus (Arrenurus) liliaceus sp. nov., holotype 6 (unless stated otherwise): 15, ventral view; 16,
dorsal view; 17, lateral view; 18, palp; 19, ventral view, paratype 9. Scale lines, 50 pm (Figure 18), 200
pm (Figures 15-17,19).
Australian Arrenurus 239
occurred at the type locality, both represented by of body concave. Posterolateral corners very
one female. I assigned the small female to A. distinct. Gonopore 145 long; genital valves with
harveyi, the large female to A. liliaceus sp. nov., large chitinous patches, the anterior patch
because the male of liliaceus is larger than harveyi. triangular, the posterior patch rounded. Genital
The female of A. harveyi is close to A. liliaceus and plates long, straight and narrow, not extending to
A. pseudoaffinis and differs only in the shape of the lateral body margin, laterally widened (Figure 19).
chitinized patches of the genital valve. The shape V2 on humps. Lengths of PI-PV: 29, 77, 62, 96, 60.
of the ligulate process separates the male from PII with 2 anteroventral and 1 more dorsally
other species. located seta on medial side of PII; hump of PIV
absent. Lengths of I-leg-4-6: 170, 155, 165; lengths
Etymology of IV-leg-4-6 223, 175,165.
The species is named after Dr M.S. Harvey.
Remarks
Arrenurus (Arrenurus) liliaceus sp. nov. The male is close to A. shoesmithi Wiles from
Figures 15-19 Malaysia (Wiles 1993). This last species has a
petiole gradually tapering posteriorly, a trapezoid
Material Examined hyaline membrane with a posterior margin which
is only slightly concave, and a dorsal shield not
Holotype
narrowed in the middle. Females of the two species
8, Chinderwariner Pool, Millstream-Chichester
differ in the shape of the genital plates. The male of
National Park, Western Australia, Australia, 15
A. latipetiolatus Piersig from the Bismarck-Archipel
August 1994 (WAM).
(Piersig 1903) also has a wide petiole, but this
Paralype petiole is narrowed anteriorly. For similar species
Australia: Western Australia: 1 $, same data as of the female see discussion at A. harveyi sp. nov.
holotype (WAM).
Etymology
Diagnosis The species name is derived from the fact that
Male with a broad, posteriorly rounded petiole; the type locality the Chinderwariner Pool, has an
ligulate process absent; hyaline membrane large abundant growth of water lilies.
but thin, indented laterally and posteriorly.
Females with distinct posterolateral comers of the
body, genital valves with chitinous patches, Arrenurus (Arrenurus) mantonensis sp. nov.
anterior patch triangular, posterior rounded; Figures 20-24
genital plates straight and narrow, laterally
Material Examined
widened.
Holotype
Description 8, Manton Dam, Northern Territory, Australia, 1
Male August 1994 (NTM).
Body 1242 long and 883 wide. Body colour
blueish-green. Anterior margin of body concave. Par a types
Cauda and pygal lobes well developed. Dorsal Australia: Northern Territory: 1 8 (not fully
furrow incomplete (Figure 16). D1 and D4 on sclerotized) (ZMA), 2 9 (one not fully sclerotized)
humps (Figure 17). Gonopore 65 long. Genital (ZMA, NTM), 2 nymphs (ZMA), same data as
plates long, wing-shaped, not extending to lateral holotype.
body margin (Figure 15). Hyaline membrane
present, but very thin and difficult to observe, Diagnosis
laterally and posteriorly indented. Petiole large, The very slender PIV is diagnostic for the new
widened in the middle, posterior margin convex. species. Petiole with bifurcated setae; hyaline
Petiole 184 long (measured from ventral view) and membrane absent.
155 wide. Ligulate process absent. Lengths of PI-V:
41, 91, 89, 118, 73. PIV with a hump; P1I with one
Description
seta near anteroventral corner and two setae
located near the middle of anterior margin (Figure Male
18). Lengths of I-leg-4-6: 214, 180, 221; lengths of Body 917 long (including petiole) and 689 wide.
IV-leg-4-6: 291,194, 184. IV-leg-4 with a long spur. Body colour yellowish. Anterior body margin V-
shaped. Cauda well developed, pygal lobes short
Female and broad. Dorsal furrow extending onto cauda
Body 1140 long and 951 wide. Anterior margin (Figure 21). D1 on humps, lateral of D4 a seta on
240 H. Smit
Figures 20-24 Arrenurus (Arrenunis) mantonensis sp. nov., holotype 6 (unless stated otherwise): 20, ventral view; 21,
dorsal view; 22, lateral view; 23, palp; 24, ventral view, paratype $. Scale lines, 50 pm (Figure 23), 200
pm (Figures 20-22, 24).
humps (Figure 22). Gonopore 68 long. Genital Female
plates long and narrow, extending onto lateral side Body 941 long and 844 wide. Anterior body
of body (Figure 20). Posterior margin of genital margin slightly concave. Posterolateral comers of
plates with numerous long setae. Petiole 155 long body distinct, posterior body part truncated,
(measured from ventral view) and 102 wide, with posterior body margin straight. Dorsal furrow
a rhomboid hyaline area. Petiole ventrally with two complete, dorsal shield 815 long. D1 on very small
bifurcated setae, medial part of petiole with a humps. Medial margin of CX4 larger than medial
finely serrated lateral margin. Hyaline membrane margin of CX3. Medial distance of CX4 less than
absent. Cauda dorsally with a tubercle, just width of one genital valve. Gonopore 107 long,
anterior of petiole. Lengths of PI-PV: 29, 54, 31, 82, genital valves without chitinous patches. Genital
29; PII with 3 setae on medial side, PIV very plates long and straight, anterior margin slightly
slender, with a very short anterior margin (Figure undulating (Figure 24). Lengths of Pl-PV: 25, 52,
23). Lengths of I-leg-4-6: 146, 136, 194. Lengths of 34, 78, 25; palp as in male. Lengths of I-leg-4-6: 160,
IV-leg-4-6: 204, 165, 112; IV-leg-4 without a spur. 165, 175. Lengths of IV-leg-4-6: 228,194, 175.
Australian Arrenurus 241
Figures 25-29 Arrenurus (Megaluracarus) caeruleus sp. nov., holotype <J (unless stated otherwise): 25, ventral view; 26,
dorsal view; 27, lateral view; 28, palp; 29, ventral view, paratype 9. Scale lines, 50 pm (Figure 28) 200
pm (Figures 25-27, 29).
Remarks Material Examined
The very slender PIV, with the very short Australia: Western Australia: 1 $, Deep Reach
anterior margin, is unusual in Arrenurus, and easily Pool, Millstream-Chichester National Park, 15
separates the new species from other members of August 1994 (ZMA).
the genus.
Remarks
Etymology A widespread species, known from New
Named after the type locality. Caledonia, Sumatra, Java, Burma, India, Burma,
Singapore, Sri Lanka and Sulawesi. The new record
is the first for Australia.
Arrenurus (Arrenurus) rouxi Walter
Arrhenurus pseudoaffims (in part, $) Piersig, 1906:
360. Arrenurus (Megaluracarus) caeruleus sp. nov.
Figures 25-29
Arrhenurus rouxi Walter, 1915: 120; Walter, 1928:
259. Material Examined
Arrenurus rouxi Walter: K. Viets, 1935: 9; Cook, Holotype
1967: 228; Lundblad, 1969: 417; Wiles, 1990: 281. <J, Pools upstream of Waterfall Creek, Kakadu
242 H. Smit
National Park, Northern Territory, Australia, 25 Megaluracanis have been described from Australia.
July 1994 (NTM). Most closely related are A. margatelhis Cook, which
differs from the new species in medial projection at
Paratypes the posterior margin of the cauda, and A. cheetus
Australia: Northern Territory: 2 <J, 6 2, same Cook, which has a different petiole. The female is
data as holotype (NTM); 2 <J, Lily Ponds Falls, very close to A. thienemanni K.O. Viets. The dorsal
Katherine Gorge National Park, 27 July 1994 shield of caeruleus is smaller, the ratio of body
(ZMA); 1 6 (WAM), 4 2 (WAM, ZMA), Plunge length/length of dorsal shield is 1.58-1.70 for
Pool, Edith Falls, Katherine Gorge National Park, caeruleus and 1.39-1.48 for thienemanni. Further, A.
30 July 1994. caeruleus does not have the large anterior seta on
the dorsal margin of PIV. Like thienemanni, females
of caeruleus are variable in body shape.
Diagnosis
PII with patch of setae; body dorsally with short
projection (rostrum). Cauda of male rounded and Etymology
slightly enlarged posteriorly; posterior margin of The species is named for its conspicuous blue
cauda with a small, irregular shaped hyaline area. colour.
Female with short and broad genital plates, sloping
posteriorly.
Arrenurus (Megaluracarus) gilvus sp. nov.
Figures 30-34
Description
Material Examined
Male
Body 902 (854-1028) long and 475 (466-524)
Holotype
wide. Body colour blue. Anterior body margin
<5, Lily Ponds Falls, Katherine Gorge National
straight. Anterior end of body dorsally with a short
Park, Northern Territory, Australia, 27 July 1994
projection (rostrum). Dorsal shield incomplete,
(NTM).
dorsal furrow extending onto lateral sides of body.
D1 on small humps (Figure 27). Cauda well
Paratypes
developed, 330 long, posterior part slightly
Australia: Northern Territory: 1 2, same data as
enlarged, posterior margin rounded (Figure 26).
holotype (NTM); 1 6, Southern Rockhole,
Posterior margin of cauda with a small, irregular
Katherine Gorge National Park, 27 July 1994
shaped hyaline area. Gonopore 58 long. Genital
(ZMA).
plates short, anterior and posterior margins
rounded, extending to lateral body margin (Figure
25). Petiole present, dagger-like; one of the Diagnosis
paratypes has a double petiole. Lengths of PI-PV: Body colour yellowish, body dorsally with small
29, 62, 35, 69, 26; PII with a patch of setae (Figure rostrum. PII with large patch of setae. Cauda of
28). Lengths of I-leg-4-6: 114, 126, 116. Lengths of male posteriorly widened, with straight to slightly
IV-leg-4-6: 155, 136, 165; IV-leg-4 with a short, concave posterior margin; posterodorsally on
truncated spur. cauda two peg-like setae; posterior margin of
cauda with small hyaline area. Female with short,
broad, posteriorly sloping genital plates.
Female
Body 863 (728-883) long and 698 (611-737) wide.
Body slender to broad egg-shaped, posterolateral Description
comers absent or present. Anterior body margin
Male
rounded, rostrum short. D1 not on humps. Dorsal
Body 1048 (1004) long and 524 (495) wide. Body
shield complete, 427-504 long. Medial margin of
colour yellowish. Anterior body margin rounded,
CX4 larger than medial margin of CX3. Medial
near anterior margin a small rostrum. D1 on small
distance of CX4 about as large as width of one
humps (Figure 32). Postocularia and associated
genital valve. Gonopore 126 long; genital valves
setae of D2 very long. Cauda well developed,
without chitinous patches. Genital plates short and
longer than wide, posteriorly widened, posterior
broad, sloping posteriorly (Figure 29). Lengths of
margin of cauda straight to slightly concave (Figure
PI-PV: 29, 73, 36, 52, 34; palp as in male. Lengths
31). Dorsally on cauda, near posterior margin two
of I-leg-4-6: 116, 126, 97. Lengths of IV-leg-4-6: 165,
rounded peg-like setae; posterior margin of cauda
175, 165.
with a very small hyaline area. Genital plates short
and broad, extending to lateral body margin
Remarks (Figure 30). Lengths of PI-PV: 29, 65, 35, 68, 23; PII
A small number of species of the subgenus with large patch of setae on a bulge (Figure 33).
