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341

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339

340 Figures 339 and 340, 0, dorsal and ventral views

Figure 341, 2, dorsal view

IXODES ALLUAUDI
(After Theiler 1941)

PLATEC

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This nymph was taken at 8000 feet elevation in the Imatong Mountains from the tail of an unidentified Crocidura shrew. It is specimen number 1950.3_20-42 in British Museum (Natural History) collections and has recently been identified by Arthur (1956 correspondence).

DISTRIBUTION

Ixodes alluaudi is known only from the Imatong Mountains of the Sudan, highland forests and alpine meadows of Tanganyika, Kenya, and several localities in Basutoland and the Union of South Africa. Intervening populations undoubtedly have been overlooked.

EAST AFRICA: SUDAN (Not previously recorded. Arthur, ms.). TANGANYIKA (Neumann 1913). KENYA (Arthur, ms.).

SOUTHERN AFRICA: UNION OF SOUTH AFRICA (Theiler 1941. Arthur, 3.). BASUTOLAND (Arthur, ms.).

HOSTS

The species of the Sudan host is not known. Crocidura shrews recorded from the Imatong Mountains during the present study are C. hildegardeae phaios and C. nyansae toritensis (common), both of which are described as new subspecies (Setzer 1956). The host of Neumann's material was not stated.

From Theiler's (1941) study of South African data it appears that the red shrew, c. flavescens, may be the true host and infes_ tation of other rodents and insectivores is incidental. These hosts are the vlei or groove_toothed rat, Otomys irroratus subsp.; the four-striped grass mouse, Rhabdomys pumilio subsp.; Brant's gerbil, Tatera brantsi maecalinus; Lobengula's gerbil, T. loben gulae subsp.; and the Eastern Province golden_mole, Amblysomus hottentotus subsp. Thirteen collections were made from red shrews and twelve from other hosts. Collections from red shrews also contained the most specimens. Arthur (ms.) records the same hosts and adds Cryptomus capensis.

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BIOLOGY

Life Cycle

"Probably a three host tick; adults, nymphs, and larvae invariably have been collected separately except for two records from Brant's gerbil when adults and nymphs were taken together" (Theiler 1942).

Ecology

The fact that the few specimens known from the Sudan and Tanganyika were taken in highland forests or alpine zones is of some interest. In southern Africa this altitudinal distri. bution is not so restricted.

The red shrew frequents runways made by rodents in long grass beside streams and rivers. In drier areas, this tick is taken in the smaller and shorter runways of other rodents associated with bunches of grass at the base of thorn bushes and other shrubs. Red shrews also inhabit the underground nesting burrows abandoned by rodents (Theiler 1941).

REMARKS

Theiler (1941) has made an extensive study of the morpho logical features of this species to show its exceptionally prim itive characters. This report should be studied by anyone in terested in tick morphology or phylogeny.

IDENTIFICATION

The following notes are a brief abstract of Theiler's (1942) descriptions, which also include those of the larva and nymph. Arthur (ms.) also redescribes this species; his manuscript is not available at the time this is written but he has (correspondence) confirmed the accuracy of Theiler's description and of this sum mary

Male. This is a small light brown tick with slender legs. The scutum, approximately twice as long as wide and sharply pointed at both ends, bears fine, evenly distributed punctations posteriorly and coarser punctations anterolaterally. Cervical grooves are vaguely indicated. The short, converging palpi, which overlap the short, blunt hypostome, are borne on a lateral projection of the basis capituli. The ventral plates and coxae are most distinctive (Figure 340).

Female. Palpi are narrow and elongate but also borne on a lateral projection from the basis capituli. The scutum is widest just posterior of midlength and abruptly converging posteriorly; its faintly reticulate surface bears a few medium size punctations and scattered hairs; cervical grooves are absent; lateral grooves are fine. Ventrally, genital grooves are long, straight, diver. gent; anal grooves are truncate anterior of the anus, thence long and subparallel tending to converge distally.

IXODES RASUS

ARTHUR (1956 correspondence). Preliminary study of a large amount of material referrable to this name reveals that five species with closed circular or pointed anal grooves are involved. Incidental ly, Neumann's type material, from hyrax has pointed anal grooves. Rio Muni specimens especially are easily distinguishable from all others. Neumann's material from Togo (Berlin Museum), now at Toulouse, is I. oldi, although Neumann had identified it as I.

What Nuttall considered as I. rasus is a new species that is now being described. Schulze's descriptions of the I. rasus group are very vague and it is difficult to associate his so-called subspecies with available material. I. rasus and related species are no more variable than other Ixodes species and are easily separated once adequate criteria have been established.

rasus.

N.B. The exact status of the pair of specimens illustrated herein (Figures 222 to 225) and of the single male from the Sudan (page 550) has not yet been determined.

EXODES SCHILLINGSI

TENDEIRO (1955). Mozambique. Review of previous reports from

colony.

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