Tiflovia, a new genus of pygiopsyllid flea from New Guinea, with notes on convergent evolution and zoogeography (Siphonaptera).

Abstract

Tiflovia, new genus, described on the basis of 2 new species, T. pachnopoata, n. sp. and T. stellalpestris, n. is one of the few pygiopsyllids showing marked thoracic modifications associated with lessened jumping ability, coupled with almost complete reduction of the eye. Thereby agreeing with Zyx and Astivalius, it is separable from the former by the absence of strongly oblique caudoventral margins on the abdominal sterna, and by the possession of 2 antepygidial bristles instead of 3. It is immediately distinguishable from Astivalius by the lack of tibial combs and by having a highly convex sensilium and very short maxillary palpi. Tiflovia is known only from Mt Giluwe and the Star Mts in Papua New Guinea, where it infests Pogonomelomys ruemmleri, and has been collected only in alpine grassland, above timber line. Data are presented indicating that there is no true alpine fauna of mammals or ectoparasites in New Guinea (or on Mt Kinabalu, Borneo), thereby confirming conclusions reached by others regarding free-living insects. This lack of bioendemiciry in the alpine terrain is attributed to the geological youthfulness and nonspecific nature of the habitats above timber line. The apparent restriction of Tiflovia to alpine terrain is therefore exceptional in New Guinea and of unusual interest, and suggests the possibility that elements of an older fauna exist in yet undiscovered refugia. However, it is also pointed out that despite its special morphological modifications, which are discussed as being adaptive and serving as examples of convergent evolution, Tiflovia may actually be a relatively youthful taxon, dating back only to the upper Pliocene. The rate of evolution for certain genera of Siphonaptera may therefore be more rapid than had been realized. Evidence is summarized indicating that the affinities of the New Guinean siphonapteran fauna are with the Australian Region, not the Oriental (and hence unlike the free-living insects) and certainly not with the Palaearctic Region. The lack of true Palaearctic elements is believed to be a factor in the absence of an alpine fauna. Reasons are advanced for regarding the modifications of the pronotal comb as adaptations associated either with the pelage of the hosts or with their habits.