Timiriaseviinae Mandelstam, 1960

Hiruta, Shimpei F. & Mawatari, Shunsuke F., 2013, Ostracods (Crustacea) from Sarobetsu Marsh, Northern Hokkaido, Japan: Taxonomy and Phenology with Description of Pseudocandona tenuirostris sp. nov., Species Diversity 18, pp. 57-74 : 70-71

Subfamily Timiriaseviinae Mandelstam, 1960 Metacypris digitiformis Smith and Hiruta, 2004 ( Fig. 17 )

Metacypris digitiformis Smith and Hiruta, 2004: 38 , figs 2, 3, 4A, B, 5; Smith and Janz 2009: 230, fig. 5I, J.

Material examined. ZIHU 3903 , 1 male, site E ( Table 1, Fig. 1 ), 6 August 2005, dissected, soft parts mounted on 17 slides; ZIHU 3904 , 1 male, site B ( Table 1, Fig. 1 ), 13 May 2006, dissected, soft parts mounted on 16 slides; ZIHU 3905 , 1 female, site E, 6 August 2005, dissected, soft parts mounted on 16 slides; ZIHU 3906 (1 male), ZIHU 3907 (1 female), ZIHU 3908 (1 female), site E, 17 July 2007, mount- ed on stubs for SEM observation .

Comparative material. Holotype, ZIHU 2063 , male . Paratype, ZIHU 2064–2067, 4 females; ZIHU 2071–2072, 2 males.

Remarks. There are a few minor morphological differences between the holotype from Kushiro Marsh and our specimens from Sarobetsu Marsh. In the Kushiro Marsh specimens, the medial ridge of the hemipenis attaches to about the middle of the dorsal ridge or at the end of the zygum, and the entire outer margin of the hemipenis is gradually curved ( Fig. 17B ). In the Sarobetsu Marsh specimens, the medial ridge attaches to the end of the dorsal ridge, and the hemipenis has the outer margin gradually curved over the proximal two-fifths, but nearly straight distally ( Fig. 17A ). The shape of the upper clasping ramus (UR) also shows subtle variation. This backward-directed ramus is usually straight in the Sarobetsu population ( Fig. 17A ), but in a few specimens it is identical in form to that in the Kushiro population ( Fig. 17B ). The carapace and soft parts are identical between the two populations, and we attribute the above morphological differences to geographical variation in a single species.

Figures

Fig. 17. Comparison of the hemipenis of Metacypris digitiformis Smith and Hiruta, 2004 between specimens from the the Sarobetsu and Kushiro populations. A, Right hemipenis typical of the Sarobetsu population, male, ZIHU 3903; B, hemipenis typical of the Kushiro population, redrawn from Smith and Hiruta (2004); arrowheads indicate point of attachment to MR. Scale bar: 100µm.

Fig. 1. Map showing the location of Sarobetsu and Kushiro Marshes (above); diagram of study area (below), with sampling sites A to E indicated by circles; black arrows indicate direction of river current.