 Ixodes anatis female (figure adapted from Dumbleton (1953)) (click on thumbnail for larger image). |
 Ixodes anatis larva (figure adapted from Dumbleton (1953)) (click on thumbnail for larger image). |
 Ixodes anatis male (figure adapted from Dumbleton (1953)) (click on thumbnail for larger image). |
Species name
Ixodes anatis Chilton, 1904
Common name
Kiwi tick
Naming history
Ixodes anatis Chilton, 1904 (accepted name)
Hosts
Kiwi (Apteryx sp.), Grey duck (Anas superciliosa), Canada goose (Branta canadensis ).
Description of larva
From Dumbleton (1953).
- Body sub-circular; length including hypostome 1.5 mm, width 1.2 mm, setae present, about same size as in I. eudyptidis.
- Capitulum
- Palpi palpal article 1 transverse, 2 and 3 not separated; combined length 0.13 mm, width 0.05 mm, long and thin, slightly flattened mesally; 4 inserted ventrally on apex of 3, sub-glohose. Basis ventrally with 2 para-median sensory pores or short setae.
- Hypostome spatulate; length 0.13 mm, width 0.05 mm; dentition 2/2, with about 8 teeth per file.
- Scutum wider than long; length 0.32 mm, width 0.35 mm, widest anteriorly at about length. Four setae on anterior margin behind neck, 2 on each side before lateral angle.
- Legs
- Coxae coxae 1�3 with posterior external spurs, coxal setae 3, 2, 2 or 3, 3, 2.
- Tarsi tarsus 1, length 0.25 mm, slightly humped and tapering abruptly.
- Metatarsus metatarsus 3, 0.07 mm long, tarsus 3, 0.16 mm long.
- Anal lobes one seta on each.
Description of nymph
From Dumbleton (1953).
Resembles female
- Scutum length 0.61 mm., width 0.67 mm.
- Dentition 2/2, with 10 teeth in outer file.
- Legs
- Coxae coxa 1 with prominent external spur, coxae 2 and 3 with very small spurs.
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Description of female
From Dumbleton (1953).
- Body engorged specimens up to 10 mm long, 7 mm wide.
- Capitulum
- Basis capituli short and broad with straight rounded ridge dividing it from neck, sides with slight rounded cornua posteriorly. Porose areas separated by slightly less than their length.
- Palpi with article (segment) 1 large and massive, and article (segment) 2 twice as long as 3.
- Hypostome dentition 3/3 apically, then 2/2, 12 to 14 teeth in outer file.
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- Scutum Sub-pentagonal, wider than long, length 1.5 mm, width 1.65 mm, lateral and posterior angles broadly rounded.
- Venter Anal grooves not joining in front of anus hut forming two crescentic lines converging in front of and behind anus.
- Legs
- Coxae coxa1 with external spur, coxae 2�4 without spurs.
- Trochanters trochanter 1 with dorsal spur. Trochanters 1�4 with distal posterior gibbosity or spur.
- Tarsi tarsus 4 short, slightly humped, and tapering abruptly.
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- Spiracle long, ovoid, long axis transverse.
Description of male
From Dumbleton (1953).
-
Body oval 3.4 mm., width 2.2 mm (including capitulum).
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Capitulum
- Basis capituli widest, 0.47 mm., immediately behind article 1 of palps, sides strongly converging posteriorly to neck, basis and neck separated dorsally by a straight carina, not separated ventrally. Ventrally there is a short seta on each side of basis behind article 1 of palps. Cornua and auriculae absent. Neck width 0.30 mm., sides sub-parallel or slightly divergent posteriorly. Palpal joints 2 and 3 sub-equal, combined length 0.30 mm.
- Palpi short. clavate, rounded apically, article (segment) 4 small, rounded.
- Hypostome short, stout; length 0.25 mm. slightly swollen apically and slightly emarginate at tip, but not strongly bifid. Dentition variable 2/2 or 3/3, outer file of 6 broad teeth which are twice as wide as the inner teeth: teeth of inner files only present in first three or four rows.
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- Scutum length 2.8 mm., width 2.0 mm., smooth, shining, hairless,. castaneous. Scapulae small, cervical grooves not strongly developed, lateral carina absent, marginal body-fold narrow.
- Venter ventral plates smooth, shining, castaneous, impunctate except around genital region and between coxae 4 and spiracular plate. Hairless except for scattered short setae on anal and adanal plates. Median plate longer than wide, length 1.6 mm, width 1.3 mm. Anal plate approximately as wide as long, length 0.57 mm, anterior margin straight, lateral and posterior margins rounded, widest at mid length. Pregenital plate between coxae 1 transverse, somewhat crescentic, concave anteriorly and convex posteriorly. Jugular plates absent. Epimeral plates extending anteriorly to coxae 4, separated by unpigmented area from pigmented plate between coxae 2�4 and median plate. A narrow plate on anterior and mesal margins of spiracular plate.
- Legs
- Coxae contiguous. No internal spur on coxa 1; definite external spurs on coxae 1�3, small or absent on 4, the spurs more rounded than triangular. Setae not strongly developed or numerous.
- Trochanters posterior gibbosity on trochanters 1 and 2, spurs on 3 and 4. Dorsal spur on trochanter 1.
- Tarsi tarsis 1 humped; length 0.75 mm. Tarsus 4 tapering abruptly, length 035 mm. metatarsus 4, length 0.22 mm.
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- Spiracular plate ovoid, long axis longitudinal, macula slightly behind mid-length, length 0.45 mm.
- Genital aperture between coxae 2.
- Anal lobes three pairs of setae.
Disease relationships
Babesia kiwiensis is thought to be vectored by Ixodes anatis . However comfirmation of this releationship is still needed as the only evidense for this comes from B. kiwiensis DNA found in a tick taken from an infected bird.
Distribution
New Zealand: North and South Island.
Status in New Zealand
Endemic
Comments, identifying features and similar species
AsI. anatis has not yet been intensively studied little is known about its biolgy. However, it is likely to be a three host tick that is nidicolous (lives in the kiwi dens or burrows).
Ixodes anatis can be distingusihed from other Ixodes species that occur in New Zealand by the following features;
- Hosts: I. anatis is the only Ixodes species in New Zealand that has been confirmed as feeding on kiwi (Apteryx sp.). The only other tick that has been identified as feeding on kiwi is Haemaphysalis longicornis. The two species can be separated from each other by the anal groove (passes around the anterior of the anus in I. anatis and posterior of the anus in H. longicornis ), presence or absence of festoons (absent in I. anatis, present in H. longicornis) and shape of the second segment of the palps (extended laterally giving palps a wedge shaped appearance in H. longicorinis ).
- Males: The males of I. anatis can be separated from other species of Ixodes in New Zealand as the pregenital plate is transverse or bow shaped and the jugular plates are absent.
- Females: The females of I. anatis can be separated from other species of Ixodes in New Zealand as the suctum is broader than long, coxal armature is limited to a single external spur on coxa 1; the second palpal article (segment) is approximately twice as long as the third; hypostomal dentition is 2/2.
- Nymphs: The nymphs of I. anatis can be separated from other species of Ixodes by the coxal armature (coxa 1 with prominent external spur, coxae 2 and 3 with very small spurs); lack of auriculae on the basis capituli.
Useful references
Barker SC & Murrell A 2004. Systematics and evolution of ticks with a list of valid genus and species names. Parasitology, 129: S15-S36.
Bishop DM. & Heath ACG 1998. Checklist of ectoparasites of birds in New Zealand. Surveillance. Special Issue: Parasites of Birds in New Zealand. 25: 13-31.
Camicas, JL, Hervy JP, Adam, F & Morel PC 1998. Les Tiques de Monde. Nomenclature, stades decrits, hotes, repartition. The ticks of the world. Nomenclature, described stages, hosts, distribution (Acarida, Ixodida). France , Orstom Editions.
Chilton, C 1904 A species of Ixodes parasitic on the Grey Duck. Transactions of the New Zealand Institute, 36: 201-202.
Dumbleton, LJ 1953. The ticks (Ixodoidea) of the New Zealand sub-region. New Zealand Cape Expedition Series Bulletin, 14: 1-28.
Heath, ACG 1977. Zoogeography of the New Zealand tick fauna. Tuatara 23:26-39.
Heath ACG, 2009. A review of the ectoparasites of Apteryx spp.(kiwi) in New Zealand, with new host-parasite records, and an examination of the biology of Ixodes anatis (Acari: Ixodidae). In prep.
Horack IG, Camicas, J-L & Kierans, JE 2002 The Argasidae, Ixodidae and Nuttalliellidae (Acari: Ixodida): a world list of valid tick names. Experimental and Applied Acarology, 28: 27-54.
Jefferies R, Down J, McInnes L, Ryan U, Robertson H, Jakob-Hoff R & Irwin P 2008. Molecular characterisation of Babesia kiwiensis from the Brown kiwi (Apteryx mantelli). Journal of Parasitology 94 (2): 557-560.