Rhamphothrips Karny

Mound, Laurence A. & Tree, Desley J., 2011, New records and four new species of Australian Thripidae (Thysanoptera) emphasise faunal relationships between northern Australia and Asia, Zootaxa 2764, pp. 35-48 : 40-41

Rhamphothrips Karny

Rhamphothrips Karny, 1913: 123 . Type-species Rhynchothrips tenuirostris Karny.

Adults of this genus of Thripidae have a particularly elongate mouth-cone ( Fig. 26 ) and small head ( Fig. 24 ), and the males of some species exhibit remarkable differences in structure between large and small individuals ( Tyagi et al., 2008). This type of male polymorphism is rare in Thripidae , although it is common among species of the family Phlaeothripidae that exhibit male/male competitive behaviour ( Mound, 2005). Unfortunately, for none of the species of Rhamphothrips is there any information on the behaviour of these large and small males, and moreover there has been almost no information concerning their host associations.

The genus Rhamphothrips is closely related to one other Old World genus, Exothrips Priesner. Females of species in these two genera share one remarkable character state: on sternum VII the median two pairs of setae, S1 and S2, are close together medially, and far distant from S3, the lateral third pair ( Figs 18 , 30 ). Moreover, unlike most Thripinae , adults in these two genera have no elongate posteroangular setae on the pronotum. Exothrips and Rhamphothrips are not clearly distinguished from each other ( Mound & Walker, 1987), although species of the latter have the head unusually small and the mouth cone exceptionally long, whereas species of the former have the head and pronotum transverse as in most Thripinae . Unfortunately, the apparent length of the mouth cone depends to a large extent on the orientation of slide-mounted specimens, and the species described from Africa seem to have a shorter mouth cone than those from the Oriental and Australian regions. Among the remaining Thripinae , only females of Tusothrips have the median two pairs of setae placed particularly close to each other ( Fig. 31 ), but Tusothrips species have two pairs of prominent posteroangular setae on the pronotum ( Fig. 32 ). Despite this, there is a tendency among species of Anaphothrips for the median two pairs of setae on sternite VII of females to be closer to each other than to the lateral pair.

The type species of Rhamphothrips was based on a single female from Java, and Bhatti (1978b) has given an account of the confusing early references to this specimen. The genus currently includes 14 species, all from the Old World tropics. Bhatti (1977) provided a key to distinguish four species from India, under the synonymic name Perissothrips, and Bhatti (1978b), in establishing three generic synonyms of Rhamphothrips , provided a full diagnosis of the genus together with a more extensive key to distinguish ten species. Subsequently, Sakimura (1983) described R. pandens , and this is known to be widespread from northern Australia across the Pacific and into the Caribbean. From northern India Kulshrestha & Vijay Veer (1984) described R. santokhi as having the posterior abdominal segments dark brown, in contrast to the uniformly yellow colour of all other members of the genus. Specimens of R. santokhi , identified by Richard zur Strassen and taken from flowers of Macaranga gigantea in Malaysia (Gombak near Kuala Lumpur), have the median pair of setae, S1, on the female seventh sternum much smaller than setae S2, a condition also found in another Indian species, R. parviceps (Hood) . Finally, Wang (1993) described R. quintus from Taiwan. Females of this species have the median two pairs of setae on sternum VII equally long (pers. comm. C-L Wang 2010), and thus similar to the condition in R. pandens and two further species described below from Australia ( Fig. 18 ). However, R. quintus differs in that the females have a small tooth at the inner apex of the fore tibia, and the males have extensive tooth-like craspeda laterally on terga IV–VIII.

Large and small males of the new species described below from Australia differ considerably in structure. This intraspecific variation in males contrasts with the fact that females of these new species are scarcely distinguishable from each other. Males are chosen as holotypes of the two new species described below, because of the structural similarities between females. Currently it is not possible to identify many female specimens of this genus from Australia that have been collected with no associated males.

Figures

FIGURES 24 – 26. Rhamphothrips cissus. (24) head & pronotum; (25) meso & metanotum, abdominal terga I – II; (26) mouth cone and pterothoracic sterna.

FIGURES 15 – 23. Rhamphothrips species. R. amyae 15 – 19: (15) antenna; (16) head & pronotum; (17) male terga V – IX; (18) female sterna VI – VII; (19) male fore tibia & tarsus. R. cissus 20 – 21: (20) thoracic sterna; (21) male terga V – IX. R. pandens (22) male terga IV – IX. R. tenuirostris (23) male terga VI – IX.

FIGURES 27 – 32. Rhamphothrips and Tusothrips. R. tenuirostris 27 – 30: (27 – 28) large and small males, fore coxae and mesosternum; (29) meso & metanotum and abdominal terga I – II; (30) female sternum VII. T. setiprivus 31 – 32: (31) female sternum VII; (32) head, thorax and abdominal terga I – II.