Species Content Page

Non-insects
Australian paralysis tick
Ixodes holocyclus Neumann (Acarina: Ixodidae)
Status
Native to Australia
Dorsal view - female Zoomify

Caption: Australia: New South Wales
Source: Simon Hinkley & Ken Walker Museum Victoria

Diagnosis: A large tick when fully engorged; scutum about as long as broad and broadest a little posterior to mid length, with strong lateral carinae; capitulum relatively long porose areas deep, cornua usually absent, but when present at most only mild and rounded; auriculae present; hypostome lanceolate, dentition mainly 3/3; no sternal plate; anal grooves meeting at a point behind; all coxae with an external spur decreasing in size posteriorly; trochanters III and IV usually with small, pointed ventral spurs.

Description: Body Unfed specimens, oval , flat, yellowish, 2.6 x 1.1 mm - 3.8 x 2.6 mm; marginal groove well developed and continuous; hairs small, scattered, most numerous in region of marginal fold. Semi-engorged specimens frequently with body widest behind coxa IV and with a waist at level of spiracles. Fully engorged specimens broadly oval, attaining 13.2 x 10.2 mm, living ticks with blue-grey alloscutum, the dorsum light in colour, a dark band in region of marginal groove.  Capitulum Length 1.00- 1.035 mm. Basis dorsally 0.60- 0.68 mm in width, the lateral submarginal fields swollen and frequently delimited from the depressed, median field by ill-defined carinae; posterior margin sinuous, posterolateral angles swollen, sometimes mildly salient; porose areas large, deep subcircular or oval, the longer axis directed anteriorly, interval frequently depressed, at most about the width of one; basis ventrally with posterior margin rounded and with well-defined, blunt, retrograde auriculae. Palps long and slender, some long hairs ventrally; article I rounded and somewhat salient laterally, inner "ring" with dorsal tongue-like prolongation and ventrally semicircular and plate-like, the posterior margin of the plate extending beyond the palp; articles 2 and 3 with no apparent suture, 0.75- 0.85 mm in length and about four times as long as wide, narrowly rounded distally. Hypostome lanceolate and bluntly pointed; dentition mainly 3/3, the innermost file of small, spaced teeth, basally 2/2.
Scutum As wide as or a little wider than long, widest a little posterior to mid length, 1.6 x 1.7 mm- 2.4 x 2.4 mm, flat medianly, convex external to the long, strong lateral carinae; anterolateral margins practically straight, posterolateral margins mildly concave; posterior anle broadly rounded. Punctations numerous , fine, sometimes a little coarser medianly and laterally, shallow rugae frequently present posteriorly. Cervical grooves well defined but short. Emargination moderate. Scapulae blunt. Genital aperture On a level with coxa IV, but in engorged specimens sometimes just posterior to this level. Anal grooves Rounded anteriorly, curving behind anus to meet in a somewhat elongate point. Spiracular plate Subcircular, greatest dimension 0.40- 0.45 mm.
Legs Coxae smooth, I and II sometimes with mild rounded ridges externally, each with a row of long hairs posteriorly and an external spur, longer and more pointed than in male, and decresing in size posteriorly. Trochanter IV (and sometimes III) frequently with a small, ventral spur. Tarsi tapering a little abruptly; length of tarsus I 0.70- 0.80 mm, and of tarsus IV 0.60- 0.78 mm.

Source:

Norbert Fischer

See weblink http://www.tickalert.org.au/ixholdet.htm

Specimen contact point: Museum Victoria

Citation: Walker, K. (2006) Australian paralysis tick (Ixodes holocyclus) Pest and Diseases Image Library. Updated on 9/14/2006 1:57:55 PM. Available online: http://www.padil.gov.au

Created Date: 9/14/2006 1:57:55 PM

Last Updated: 9/14/2006 1:57:55 PM

Diagnostic Images

Abdomen

Leg Mid

Leg Mid

Mouthparts - dorsal view

Mouthparts - ventral view

Mouthparts - ventral view

Tarsi

Thorax Above

Overview Images

Dorsal

Lateral

Ventral

Other Images

Dorsal view

Engorged adult female dorsal view

Engorged adult female ventral view

Hypostome

Hypostome ventral diagnostic characters

Ventral view - female

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