Pseudocastalia arabica (Gestro, 1877)

Howarth, Brigitte & Gillett, Michael, 2009, Increasing knowledge of the entomological fauna of the United Arab Emirates and the role of private collections, ZooKeys 31 (3), pp. 119-132 : 123-125

Pseudocastalia arabica (Gestro, 1877) (Subfamily: Polycestinae )

Bilý published a series of five papers describing the Saudi Arabian buprestid fauna ( Bilý 1978, 1980, 1982, 1985, 1990). In all, some 31 species of this family were listed and discussed, but one species despite its name was absent from the lists: Pseudocastalia arabica . This is a poorly known jewel beetle from a genus that contains about seven species of wood-boring beetles from Africa and Asia. In 2008, whilst examining beetles originally from the Abu Dhabi ENHG Collection, the authors were surprised to find a total of 16 examples of this very dark sub-metallic green beetle ( Fig. 2 ). Even more surprising was the observation that all specimens had been correctly determined and labeled, something that was usually lacking even for common species in this collection. All had been collected in Abu Dhabi during 1988 to 1990 by Bish Brown.

Along with the Abu Dhabi insect collection, the Al Ain ENHG had taken charge of some miscellaneous papers and letters that dealt with the collection itself. Amongst these was found a letter on NHM headed paper dated 28 th September 1988 and addressed to Bish Brown. It gave the identity of a specimen of Pseudocastalia arabica that Brown had sent to the museum, thanked him for the specimen and reminded him that a cash remittance was required to pay for the identification! Whether it was the expense of this exercise or because the collection did not contain any other species quite as obscure as P. arabica , is unknown, but no other such letters have been found.

Since MG’s son, Conrad, was employed by the NHM as curator of Coleoptera at the time the specimens and letter were discovered, he was asked to look for Brown’s specimen in the NHM Collection. It could not be found, but the NHM did have 36 specimens of this beetle, amongst them the Paralectotype from Aden. There were 18 other examples from present day Yemen, three from present day Saudi Arabia, a couple from Somalia, one from Syria, five from India and two from Korea. Five specimens were without data, but it is impossible to say if Brown’s Abu Dhabi example is amongst these. However, from this set of data, it is obvious that the Abu Dhabi material plugs a gap in the Afro-tropical – Oriental distribution of this species, as well as providing the first records from eastern Arabia.

Apparently very little is known about the biology of Pseudocastalia species, including P. arabica , except that the larvae are borers of dead wood and some species are considered to be pests ( Abivardi 2001: Biosecurity Australia 2002). Indeed, there is anecdotal evidence on the internet of the related species P. aegyptica as a pest, infesting structural timbers in a building. There is an air of mystery surrounding the Abu Dhabi specimens of P. arabica . Why so many specimens from the same collection locality with no others known from eastern Arabia or since 1990 in Abu Dhabi? Why was this species, but no others, sent off to the NHM for identification? Could the beetles have come from infested timbers in an Abu Dhabi building in the 1980’s? We will probably never know the answers.

Figures

Figure 2. The jewel beetle Pseudocastalia arabica. A jewel beetle from the JAAENHG Insect Collection; this specimen was originally collected by J. N. B. Brown in Abu Dhabi and kept in the ENHG Collection there (photograph by B. Howarth).