Testudacarus okadai Imamura, 1976

O'Neill, Joseph C., Fisher, J. Ray, Nelson, Whitney A., Skvarla, Micheal J., Fisher, Danielle M. & Dowling, Ashley P. G., 2016, Systematics of testudacarine torrent mites (Acari, Hydrachnidia, Torrenticolidae) with descriptions of 13 new species from North America, ZooKeys 582, pp. 13-110 : 87-88

Taxon classification Animalia Trombidiformes Torrenticolidae

Testudacarus okadai Imamura, 1976

Testudacarus okadai : Imamura 1976: 279, 281-284; Imamura 1980: 342-343; Viets 1987: 724; Wiles 1997a: 201, 209; Abé 2005: 120; Abé 2006: 6; Abé et al. 2006: 14; Pešić and Smit 2007: 50.

Type series.

Holotype (1♀): Tichigi, Japan: Onisawa, Shôbuga-Hama, Nikkô National Park, 13 May 1974, by Y. Okada.; Allotype (1♂?): Tichigi, Japan: Onisawa, Shôbuga-Hama, Nikkô National Park, 13 May 1974, by Y. Okada.

The types were not examined for this publication.

Type deposition.

Holotype (1♀) and allotype (1♂?) at Taiji Imamura Collection at Ibaraki Nature Museum, Japan.

Holotype loans are not available from Ibaraki Nature Museum. The museum provided a low-magnification photograph through e-mail, though permission to print the photograph was not obtained.

Diagnosis.

These mites differ from all other Asian Testudacarinae by distribution (Japan), and from Testudacarus tripeltatus by small size (dorsal length <700 µm). Testudacarus okadai may be conspecific with Testudacarus japonicus . More research and updated descriptions are needed for a better diagnosis.

Distribution.

Throughout Honshu, Japan ( Imamura 1980).

Discussion.

A drawing of the “male” dorsum is left out of the Testudacarus okadai description. This is of the utmost importance because the sex of the “male” specimen is in question. The positioning of the genital field in relation to coxae-IV and the short coxae-II+III midline is typical of female testudacarines, but the coxal field size in relation to the venter is typical of males (Fig. 7). Furthermore, Imamura states the "feature and shape of dorsal shields are all similar to those of the female" ( Imamura 1976). Again, testudacarine male and female dorso-glandularia-4 are positioned differently with respect to the muscle scars. While his word choice of “similar” suggests this difference could exist, without a more elaborate description or a drawing it is impossible to tell ( Imamura 1976, 1980). In short, it is possible that this is an atypically small female, or a teneral female that has not undergone secondary growth and sclerotization. Imamura (1976) continues to confuse sexual dimorphism when he states: "the female of okadai n. sp. is also clearly distinguished from … japonicus … by the feature of the venter." Although this is true, it is because one is female and the other male. This casts suspicion on Testudacarus okadai . Imamura (1976) seems to be suggesting they are separate species based on his confusions about sexual differences. Testudacarus okadai could be synonymous with Testudacarus japonicus and this issue should be further explored. Wiles (1997a) offers a key to Asian species, but the characters he used to differentiate species are also differences between sexes and therefore are not useful.