Biology Reference
In-Depth Information
Genus
Hyalomma
These are medium-sized inornate ticks with long mouthparts, that is, longiro-
strate. The basis capitulum is subtriangular dorsally and eyes are situated in orbit-
like pits. The genus comprises 30 known species found all over the world, out of
which nine have been recorded from India. The male has one pair each of adanal
and accessory adanal plates. Coxa I is bifid. Hyalomma are tough, hardy ticks that
survive where humidity is low and climatic conditions are extreme. Hyalomma
species are either two- or three-host ticks.
Genus
Rhipicephalus
These are small brevirostrate, reddish or blackish brown ticks, and are inornate.
This genus contains 75 known species, eight of which occur in India, including those
belonging to Boophilus group which has been merged recently with this genus. The
basis capitulum is hexagonal dorsally and coxa I is bifid in both sexes. The male has
adanal and accessory adanal shields or plates, the shapes of which are of diagnosable
value. In ticks belonging to Boophilus group, the palpi are compressed and articles II
and III have transverse sides on the dorsal and lateral surfaces. Festoons are absent.
Males bear elongated posteriorly pointed adanal shields. Boophilus ticks are generally
one-host ticks, whereas Rhipicephalus are mostly three-host ticks.
Genus
Amblyomma
These are large ornate longirostrate ticks with festoons, but no ventral plates in the
male. The genus is represented by 12 species in India, including those belonging to
the Aponomma group which has been merged recently with this genus. There are 126
known species of this genus distributed all over the world. Species of the genus are
characterized by the usually long mouthparts. The palpal article 2 is about 2 or 3 times
as long as article 3. Almost all species belonging to Amblomma are three-host ticks,
whereas Aponomma species are usually one-host and feed exclusively on amphibians.
1.4 Keys to Genera of Indian Ixodidae
1.
Anal grooves surrounding the anus in front ................................................................ Ixodes
Anal groove distinct and contouring the anus behind or anal groove faint or
indistinct ....................... 2
2.
Without eyes ........................................................................................................ 3
With eyes ...................................................................................................................... 4
3.
Short conical palpi, article II projects laterally beyond the basis capituli, about twice as
broad as long ............................................................................ Haemaphysalis
Long narrow palpi, article II about twice as long as broad .................. Aponomma
4.
Palpi short and broad, that is, as broad as or broader than the length ................................. 5
Palpi longer than broad .........................................................................................................6
5.
Large ticks usually ornate, basis capituli rectangular dorsally ...............................6
Small inornate ticks, basis capituli usually hexagonal dorsally ............................. 7
6.
Large ticks usually ornate, basis capituli rectangular dorsally, in some species coxae
I
IV of the male increases progressively in size; coxa IV largest, spiracular plate is oval
or comma shaped................................................................... Dermacentor
Scutum ornate, male with adanal; accessory or subanal plates; each subanal plate with
three lobes ........................................................................................ Nosomma
