Hydrochus secretus Knisch

Figs. 9, 13E

Hydrochous secretus Knisch 1921: 2 .

Hydrochus mahunkai Makhan 1993; Oliva (1996).

The RBINS kindly provided five syntypes of Hydrochus secretus Knisch, which are part of the Orchymont/Knisch types collection . The syntypes consist of two males, and three females. The two males have been dissected, and are conspecific. The females appear to also represent the same species. I have selected one of the males, a good specimen, to serve as lectotype, have labeled it such, and have imaged the habitus, male genitalia and labels of this specimen ( Figs . 9, 13E). The second male was dissected by a prior worker; the specimen is quite fragmentary, in five pieces. Lectotype labels (Fig. 13E): “ Coll. R. I. Sc. N. B. Bras.Corumba [ Matto Grosso] // Kniž det. secretus m. // Coll. A. Knisch COTYPUS // Ex Coll. A. d’Orchymont // Hydrochus secretus Knisch det. J.L.Hellman // HABI- TUS/GENIT. DIGITAL IMAGES captured 2019 P. D. Perkins // [red] LECTOTYPE Hydrochus secretus Knisch desig. P. D. Perkins. ” The four non-lectotype syntypes have been labeled paralectotypes.

Remarks. Oliva (1996) placed Hydrochus mahunkai Makhan 1993 as a junior synonym of Hydrochus secretus Knisch. I have examined the holotype and male genitalia of Hydrochus mahunkai Makhan, provided through the courtesy of the HMNH, and concur with the synonymy. Labels on holotype of H. mahunkai: “Soil Zoological Exp. BOLIVIA, Guayaramerin / Beni / outskirts of town BALOGH, MAHUNKA, ZICSI // No. 424 lamping 1.XII.1966 // Hydrochus mahunkai det. D. Makhan 1993 // Holotype [red] // Hydrochus secretus Knisch, 1921 Det. A. Oliva 1996 ”. The drawing of the male genitalia in Makhan (1993) is grossly inaccurate, especially in the shape of the basal piece.