Redescription of Haemaphysalis ( Rhipistoma ) elliptica ( Koch , 1844 ) , an old taxon of the Haemaphysalis ( Rhipistoma ) leachi group from East and southern Africa , and of Haemaphysalis ( Rhipistoma ) leachi ( Audouin , 1826 ) ( Ixodida , Ixodidae )

For those involved in their identification, the systematics of the African Haemaphysalis (Rhipistoma) leachi group of ticks has been fraught with problems. Before the studies of Hoogstraal and Camicas practically all ticks in the group were considered to belong to a single species, namely Haemaphysalis (Rhipisto ma) leachi (Audouin, 1826). However, a redescription of an Egyptian population of H. (R.) leachi by Hoogstraal (1958), and his designation of a neotype, stimulated taxonomic studies of ticks belonging to this cluster of species. During the 1970s and 1980s Camicas and Hoogstraal and their co-workers elucidated taxonomic problems associated with this group and described or re-established a number


INTRODUCTION
For those involved in their identification, the systematics of the African Haemaphysalis (Rhipistoma) leachi group of ticks has been fraught with problems.Before the studies of Hoogstraal and Camicas practically all ticks in the group were considered to belong to a single species, namely Haemaphysalis (Rhipisto ma) leachi (Audouin, 1826).However, a redescription of an Egyptian population of H. (R.) leachi by Hoogstraal (1958), and his designation of a neotype, stimulated taxonomic studies of ticks belonging to this cluster of species.During the 1970s and 1980s Camicas and Hoogstraal and their co-workers elucidated taxonomic problems associated with this group and described or re-established a number of species.Hoogstraal & Kim (1985) consolidated the accumulated data on Haemaphysalis Koch, 1844 and on the subgenus Rhipistoma Koch, 1844 as well as on the H. (R.) leachi group.They placed these ticks in three subgroups, namely H. (R.) leachi, Haem a physalis (Rhipistoma) pedetes and Haemaphysalis (Rhipistoma) spinulosa.Camicas, Hervy, Adam & Morel (1998) concurred with this decision and updated the species composition of the three subgroups.The H. (R.) leachi subgroup now consisted of five species, namely H. (R.) elliptica (Koch, 1844) (1998), in their review of the ticks of the world, created two problems within the taxonomy of the H. (R.) leachi group by re-establishing two names, namely H. (R.) elliptica and H. (R.) muhsamae.The present paper addresses the taxonomic status of H. (R.) elliptica, while that of H. (R.) muhsamae, which for several decades has been considered a junior synonym of H. (R.) spinulosa, will be tackled in a future communication.Koch (1844) originally described Haemaphysalis (Rhipistoma) elliptica (Koch, 1844) as Rhipistoma ellipticum.Neumann (1897) placed this species in the genus Haemaphysalis Koch, 1844 and synonymized it with H. (R.) leachi (Audouin, 1826).Thereafter the majority of tick taxonomists considered H. (R.) elliptica to be a junior synonym of H. (R.) leachi, or a nomen nudum (Nuttall & Warburton 1915;Camicas et al. 1972).Little more than a century later Camicas et al. (1998) re-established this taxon, but gave no reasons for their decision, thus begging the question, is H. (R.) elliptica a valid taxon or not?
After an exhaustive study of many collections of Haemaphysalis that had been identified as H. (R.) leachi, and a comparison of these ticks with true H. (R.) leachi from North Africa and with the holotype specimen of H. (R.) elliptica, we concluded that many of the southern and East African ticks previously identified as H. (R.) leachi are actually H. (R.) elliptica.Furthermore, these studies enabled us to delimit the geographic distributions of both ticks.We here redescribe the male [the first description is given by Koch (1844), under the name Rhipistoma ellipticum], and the larva [the first description is given by Bedford (1934), under the name Haemaphysalis leachi], and describe the female and nymph of H. (R.) elliptica for the first time.For comparative purposes we have also redescribed all stages of development of H. (R.) leachi.

MATERIAL EXAMINED
The material examined is summarized in Tables 1, 2 and 3. Specimens from South Africa and Mozambique were studied by IGH, or by IGH and DAA, and the remainder were examined by DAA.Because of difficulties experienced in the identification of specimens we used the following material for the present study: (i) All primary identifications have been based on males.(ii) With the exception of collections from Egypt and South Africa, collections containing only females have been excluded.(iii) Females in collections containing males of two or more species have been excluded.(iv) The immature stages that we have studied come only from laboratory-reared specimens from allopatric localities within the distribution ranges of the two ticks, namely South Africa for H. (R.) elliptica, and Egypt and the Central African Republic for H. (R.) leachi.
The records of JLC have not been included because they need to be rechecked in relation to the new characters that we have found.
The descriptions of the adults of various Haema physalis species by Hoogstraal and his co-authors are characterized by the use of proportions between measurements of particular structures, mainly those of the gnathosoma.However, we could not find any exact description of the scheme of measurements taken by Hoogstraal and his co-workers, who gave only brief explanations in the texts.The exact features or structures between which some of the meas-urements were made are for the most part quite easily recognizable, but for several they are not.
Con sequently, we have taken those measurements that we consider are the most suitable for describing the species.Except for the measurements for which an explanation is given in the text, a scheme of the measurements that we have taken is illustrated in Fig. 1.
Because the larva and nymph have sometimes been inadequately described or not described at all, our set of measurements for them does not differ substantially from that used for these stages of development of previously described species.For the adults we tried to follow Hoogstraal's format so that our measurements would at least approximate those that had been used before.
Measurements for the male conscutum and female scutum and their total lengths are given in millimetres (mm), and those for the immature stages in micrometres (μm).The measurements are arranged as follows: minimum -maximum (average ± standard deviation, n = number of specimens measured).
When measuring the dorsal and ventral spurs on palpal segments II and III, it must be noted that they are not in the same plane as the gnathosoma as they are directed either dorsally or ventrally.Con- sequently, the shape and the length of these spurs vary according to the plane along which they are observed.DAA's illustrations of the gnathosoma of the larvae and nymphs are based on slide-mounted specimens, but because of the differences in planes even in these preparations, the spurs on the palpal segments are in reality longer than illustrated.This observation has been verified by scanning electron microscopy.Furthermore, in order to simplify identification for persons who may in future examine these species we have attempted to use a minimum of poorly defined diagnostic characters.
Capitulum (Fig. Coxae (Fig. 5F): I to IV each with a short, subtriangular, more or less bluntly pointed spur, extending somewhat beyond coxal margin; spur on coxae IV subequal to that of coxae III.