John Romer discovered other animals in Hong Kong: his eponymous chiggers, harvest-mites, scrub-typhus or itch mites

From Wikipedia
by Bugboy52.40

Until I received copies of gleanings from the ZSL Library archives by Jack Greatrex I had no knowledge of John Romer’s discovery of other animal species in Hong Kong. A copy of his curriculum vitae prepared about a year before his death in 1982 showed he had discovered what were then three new species of something entirely different from, his interests in amphibians and reptiles but connected with his work first as rodent control officer and then, more widely, as pest control officer for the Hong Kong Government.

Rats have parasites and as well as collecting fleas found on rats, he also collected other possible vectors of human disease, the tiny mites called chiggers or harvest mites—the  Trombiculidae, a family of arachnids. After an encounter with the microscopic chigger larvae in Guyana the very thought of them makes me itch.

Herbert Womersley

Romer sent the mites collected from rats to Herbert Womersley (1889-1962) at the South Australian Museum in Adelaide. Womersley—more on him in a future article—was the established world expert on the Acarina, mites and ticks, and continued to build a major collection at the Museum. He named three species from the specimens Romer supplied: Garhliepia romeri, Helenicula hongkongensis, Acomatacarus romeri.

What has happened more recently? Do they still stand as ‘good’ species or were they synonyms of previously described species? Fortunately I found a recent checklist of world Trombiculids. As a whole they go under a number of common names in addition to chiggers and harvest mites which some reflecting their effect on the human population or as vectors of human diseases: scrub-typhus mites, scrub-itch mites, red mites, sand mites.

The present state of play

The first named, Garhliepia romeri Womersley 1952 is now Gateria romeri and still a recognised species. The larva was collected by Romer from a rat stated to be Rattus rattus* in 1950. 

Womersley's figure showing the scutum of
Gahrliepia romeri

Womersley H. 1952. The scrub-typhus and scrub-itch mites (Trombiculidae, Acarina) of the asiatic-pacific region. Records of the South Australian Museum 10. Adelaide: South Australian Museum.

The second, Helenicula hongkongensis is now regarded as a synonymous with the earlier named Helenicula kohlsi, and therefore invalid. It was collected from Rattus rattus with the location provided by Romer: The Peak, Middle Gap Road. I wonder how the current owners of properties there—some of the most expensive in the world—view their purchases being recorded in perpetuity as the habitat of rats carrying scrub-typhus mite larvae?

Womersley H. 1957. Malaysian Parasites—XXI. A small collection of larval mites (Acarina, Trombiculidae and Leeuwenhoekiidae) from rats in Hong Kong. Studies from the Institute for Medical Research, Federation of Malaya, 28, 105-112.

The third and the other eponymous species, named by Womersley in the same publication, still stands as Odontacarus romeri.

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In summary John Dudley Romer has three currently recognised species named for him, one frog and two mites, all of which he discovered in Hong Kong in the 1950s.

…and I am still itching.

*I have written previously of trying to sort out the rats of Hong Kong. The mite larvae that Romer found were described as from from Rattus rattus. Given the current state of knowledge, it is not possible to state which of the currently recognised species in Hong Kong the mite larvae were obtained from. The choice is between Rattus tanezumi, more likely in the roof of buildings, and Rattus andamanensis, the free-living species on the hillsides.

Nielsen DH, Robbins RG, Rueda LM. 2021. Annotated world checklist of the Trombiculidae and Leeuwenhoekiidae (1758– 2021) (Acari: Trombiculoidea), with notes on nomenclature, taxonomy, and distribution. Zootaxa 4967, 1-243. https://doi.org/10.11646/zootaxa.4967.1.1