A new Arrenurus species from India ( Acari : Hydrachnidia : Arrenuridae )

A new Arrenurus species, i.e. A. hastinapurensis n. sp., is described from northern India. This is the seventh species for India of the subgenus Megaluracarus.


Introduction
With well over 950 species described, the genus Arrenurus Dugès is the most species-rich of all water mites (Smit 2012).The genus has a cosmopolitan distribution, and occurs on every continent except Antarctica.Even from remote islands Arrenurus species are known (e.g.Micronesia, Smit 2010).
In their checklist of India, Pešić et al. (2010) listed 32 Arrenurus species, with three species more of unknown origin but possibly occurring in India as well.Undoubtedly this number will increase in the future with more research done.
In this paper a new Arrenurus species will be described of the subgenus Megaluracarus K. Viets.Thus far, only six species of this subgenus are known from India (Pešić et al. 2010).

Material and methods
The types of the new species are lodged in Naturalis Biodiversity Center, Leiden (RMNH).Abbreviations used: P-1 = first segment of palp; I-leg-4 = fourth segment of first leg; Vgl-4 = ventroglandularia 4. Measurements of paratypes are given in brackets.All measurements are in µm, measurements of palp and leg segments are of the dorsal margins.
Etymology.Named after the town of Hastinapur in northern India.
Remarks.The male of the new species is close to A. dahli Piersig, 1903 from New Britain, the Aru Islands and New Caledonia (Piersig 1903, Walter 1911, 1915) but differs (in brackets A. dahli) in the incomplete dorsal shield (complete), the larger size (800-830 µm), while the cauda of A. dahli has a more anteriorly located dorsal hump.The female is in many aspects (posteromedial corners of idiosoma absent, sclerotized patches of gonopore absent, medial distance of fourth coxae much smaller) very different from A. dahli.The second paratype female is smaller, but has more or less similar genital plates.Accompanying Arrenurus species were one female of A. rostratus Daday, 1898, one female of A. madaraszi Daday, 1898 and one unknown female.