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than any other arthropod. This variety is said to be greater on continental Africa than anywhere else in the world. Other injury, apparently due to toxins, in the form of tick paralysis may be locally important. Death, lameness, or serious debilitation of the 0st by exsanguination or as the result of secondary infections at the site of attachment is not uncommon. Economic loss due to numerous punctures of animal hides by the mouthparts of large ticks is frequently reported.
Of about a hundred Ambl omma species in the world, some twenty occur in Africa and eight in the Sudan. The specific identity of most common African species appears to be settled and only in ex. ceptional instances are specimens likely to be confused. One of the chief remaining taxonomic problems among common African amblyonh mas is the A. marmoreum group, in which the range of species varia. tion needs to 5; determined for several somewhat differing forms. Observations from the present study indicate need for further re. search on the relationship between A. varie atum and A. m sum and suggest that the latter may be no more %Han a subspecies of the former. Recently a few workers have designated certain African populations by subspecific ranks that challenge further investiga.
tion. Several West African species are known from so few specimens that their validity is questionable.
This genus has been the subject of an extensive review by Robinson (1926) comprising volume four of Nutta1l's Monograph on Ticks. The African species have been keyed by Rageau and Ver.
The imature stages of most African amblyommas remain to be described with satisfactory criteria for distinguishing them.
Economically, two African species have thus far been shown to harbor or transmit human disease organisms. A. hebraeum is considered an important boutonneuse fever (“tick_typhus“) vector in South Africa and A. varie atum has been found naturally in. fected with Q fever in Frencfi Equatorial Africa near the Sudan border. Several species are important transmitters of veterinary diseases, cause damage to animal skins, or debilitate animals through the volume of blood withdrawn or by initiating wounds that develop into ugly secondary sores.
Biologically, many gaps exist in ou knowledge of African
Amblyoma distribution, host.preferences, especially of immature
stages, and life history. Birds are important immature.stage
hosts but the full extent of their importance as hosts remains to be studied. Nymphal preferences may differ from those of adults, although in some species this may not be true. Host size appears to be of some importance, for most larvae parasitize small animals; nymphs attack larger animals; and adults feed on the largest available animals, except carnivores. Immature stages, however, more frequently parasitize carnivores. Cattle and, to some extent, other domestic animals are important adult hosts and wild antelopes are also frequently parasitized. The African tortoise, rhinoceros, elephant, and buffalo harbor species mostly restricted to themselves. In general, the domestic animal parasitizing spe_ cies are well represented in study collections; others are seldom collected.
Amblvomma ticks are usually three_host parasites ad, so far as known in Kfrica, there is usually only a single generation an. nually.
1. lateral grooves extending anteriorly at least to Of SO\.1'b\J.m.............¢-....un....--....¢2
Lateral g1‘0OV6S 8-bsentooooooooocoooooouooocoooo0oooooooooa07
2. Eyes small, hemispherical, situated in a well defined depression (i.e. orbited)...................3
Eyes flat or very slightly convex, not in a depressj-onOOOOQCOOOO0‘OOOIOOCIIOQOIOOOOIOOOOOOIOOIIOIO5
3. Festoons with two colors. (Scutal or. namentation always as illustrated)................A. IEPIDUM
FeS‘b0OnS Only COlOI‘ed...-....n.......................J|
4. Scutum with numerous coarse punctations, and with a red lateral spot. (Rare in
Scutum smooth, with few scattered coarse
lateral spot. (Common in Sudan)...............§. VARIEGATIM Figures Q Ed Q5
5. Scutum smooth, with only very fine punctations. Eyes slightly convex. (Chiefly from buffalo)..........................A. coeanasus
Scutum with scattered large punctations.
6. Smaller than A. marmoreum group, nnxi...
mum size 5.5 mm. x Z.§ mm. Dark scutal
areas than in £._. marmoreum (see Figures)........._§. NUTTAL'LI Figures '73 E '7'?
Size at least 6.0 mm. x 5.0 mm. Dark
scutal areas less widely separated from
each other by pale areas than in A.
7. Scutum dark, ornamented areas small, punctations only small. (Medium size, drab tick, chiefly from elephants)...............A. THOLLDNI
Scutum extensively ornamented, some
large punctations present. (Very
rhinOceroS)OQOOOOOIOOOOOOOOOOOOOOOOOOOOCOOO00&0 Figures QZ EH 35
Eyes in a well-defined depression (i.e. orbited), hemispherical or convex.."...'.'................'..'.'.........".2
Eyes not in a depression, flat or convexOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOQOOOOQI4
Scutal punctations very coarse, uneven,
some confluent; surface rugose poste
riorly; ornamentation absent or con
sisting of only a small pale area in
posterior field; length often no
greater than width. Eyes may be
convex but not hemispherical. (Ex
tremely rare in POMPOSUM
Figures 32 and 33
Scutal punctations not so coarse, sur
face not rugose, pale areas more ex-
Scutum narrowly rounded posteriorly;
Scutum more widely rounded posteriorly,
Scutum with central and lateral areas
Scutum with either central or lateral