HY ALOMMA HUSSAINI Sharif, 1928. (Figures 198 to 201) HUSSAIN'S INDIAN HYALOMMA AND REMARKS ON THE SUBGENUS HY ALOMMINA Special note should be made of the subgenus Hyalommina, established by Schulze (1919) for the new species H. rhipicephaloides from the Red Sea area. Subsequently, Schulze (1936) placed H. lewisi from Tanganyika (and Kenya) in this subgenus and Sharif 71928 and 1936) included H. kumari and H. hussaini from India. These are discussed below. The criterion proposed by Schulze for this subgenus is the absence of subanal shields. With regard to the so called "H. rhipicephaloides", it has been our experience during field collecting and study of Hyalomma material from the Near East, Asia Minor, Arabia, North Africa, and tropical Africa, that weak, poorly developed, apparently undernourished, runts of any Hyalomma species frequently lack subanal shields. Such individuals may be part of a series in which some are typical of a common species (such as H. excavatum) and others, usually smaller and weaker, conform to the same spe cies in morphological characters, except that they lack subanal shields. It has also been noted from personal field experience and from series in British Museum (Natural History) collections, especially those of the late Professor Buxton from Iraq and Palestine, that when nymphs are removed from a bird, lizard, or small mammal and placed in a vial to molt, the resultant adults, obviously affected by abnormal, artificial conditions, are frequently frail and lack subanal shields. This feature is the rule rather than the exception among adults reared from nymphs that have become overgrown by the host skin (see below and page 447). Schulze (1932C) referred to "Hyalomma (Hyalommina) rhipicephaloides" as a "half endoparasite" (and compared it with Amblyomma nymphs to support a morphological theory). The concep tion of a separate species with unique "half endoparasitic" habits is not supported by field and laboratory observations. In several Hyalomma species observed in Egypt, long-feeding immature stages become overgrown by the host skin. Poorly developed adult "Hyalomminas" result from these nymphs. If removed early enough, such nymphs may molt into typical though frail adults of recognized species with or without subanal shields. Other larvae and nymphs that attach to the ears, which do not react to the engorging ticks by producing a large amount of tissue, usually develop normally. On the basis of many such variants among specimens of H. excavatum examined for the present study it is apparent that Delpy's (19493) synonymy of H. rhipicephaloides under H. exca vatum is correct. H. lewisi Schulze, 1936, from tropical Africa is the result of similar misinterpretation of H. truncatum by Schulze and his students. In the present collection, a few specimens of H. truncatum are poorly developed and lack subanal shields. These are similar to specimens (in the Rocky Mountain Laboratory) determined by Schulze as H. lewisi from Kenya and Tanganyika. There is no question but that H. lewisi is a synonym of H. truncatum. Delpy (1949B), probably inadvertently, listed H. lewisi as a synonym of H. excavatum. Kratz (1940) retained H. lewisi in the "subgenus Hyalommina" even though he noted that some specimens retained subanal shields while others lacked them". With regard to H. hussaini Sharif, 1928, the Rocky Mountain Laboratory collections contain enough constant specimens of this species (described below) from India to indicate beyond a doubt that H. hussaini is a valid species. It is coincidental that this species conforms to the criteria proposed for the subgenus Hyalommina; H. hussaini rather than H. rhipicephaloides might, therefore, be considered as the type species of this subgenus. The absence of subanal shields apparently has become a geneticallyestablished character in Indian populations. As stated below, other constant male and female characters also validate this spe cies. Thus, recognition of the subgenus Hyalommina would be justified. It is, however, likely that the absence of subanal shields is not a genetic character in Hyalomma populations of Africa and the Near East. Conclusions on the subgenus Hyalommina may be summarized as follows: Such an entity apparently does exist, but criteria proposed for it apply to a species (H. hussaini and possibly H. kumari) different from that originally proposed as the type for this subgenus (H. rhipicephaloides), this latter species being merely a morphological variant of H. excavatum. These conclusions are based on study of series of preserved specimens, on field rearing of specimens, and on laboratory ob servations of wild caught subdermal specimens from rodents. More formal laboratory studies on the phenomenon of loss of subanal shields among other species are indicated. Sharif (1928) also described H. hussaini brevipunctata and H. kumari from Indian populations on the basis of slight dif ferences in color, lateral grooves and tarsi. No specimens of these forms have been available for the present study. Sharif (1928) lists specimens of H. hussaini from the fol lowing India areas: Bihar, Orissa, Central Provinces and Madras and Bombay Presidencies. The subspecies brevipunctata is listed from the same areas as well as from Bengal. H. kumari is also known from the first localities and Assam and Punjab. Hosts are cattle, buffalos, horses, goats, sheep, dogs, tiger, and various kinds of deer. Sharif (1930) illustrated a specimen of H. hussaini with unequal adanal shields. Material from Portugese India has been reported (Santos Dias 1954J). Both sexes of H. hussaini have such unique morphological characters that it is difficult to comprehend why Delpy (1949B) placed this species in synonymy under H. excavatum. Sharif's (1928) original description is excellent as are the illustrations of the male. This sex is characterized by large, broad adanal shields, absence of subanal shields; bright, shiny scutum with long, pronounced lateral grooves; long, narrow posteromedian grooves, shorter and wider paramedian grooves; rarity of punctations that are widely scattered over scutal surface but usually arranged in lines bordering the posterior grooves, and small size (less than 3.00 mm. long and 2.00 mm. wide). The female also has a smooth, shiny scutum with few punctations, those present are similar to those of the male. Porose areas of the females at hand are notably large and distinct. The genital apron is unique in that it is divided by a medioposterior depression that is either a narrow, median, posterior groove or expanded posteriorly to include the posterior periphery. In outline the genital apron is subrectangular to subtriangular, in profile it is more or less gradually depressed posteriorly. The female size unengorged is only slightly greater than that of the male. |