Hirudisomatidae Silvestri, 1896

Mikhaljova, Elena V. & Lim, Kil-Young, 2006, New records of the milliped order Polyzoniida from Korean Peninsula, with a redescription of Kiusiozonium okai (Takakuwa & Miyosi, 1949) (Diplopoda), Zootaxa 1256, pp. 59-68 : 61

Hirudisomatidae Silvestri, 1896

This family contains five genera distributed in Canada, USA, Mexico, Europe and Japan. Two genera ( Kiusiozonium and Orsiboe Attems, 1909 ) are reported from Korean Peninsula. However, occurrence of the second genus in Korea requires confirmation.

Members of this family can be distinguished mainly by the following characters (after Shelley, 1995). Dorsum with a pattern of dark stripes or without pattern, coloration yellow to white; caudal metatergal margins detached from succeeding tergites, elevated or variably upturned; the collum overhanging the epicranium and the uppermost ocelli; telson broad or narrow; penes short and subconical, located caudoventrad on second male coxae; anterior gonopod sternum with strong, apically hirsute lobes; anterior gonopod coxae with or without hirsute anterior lobe.

Remarks. Shelley (1995) notes that the members of Hirudisomatidae are not readily distinguished from the members of Polyzoniidae , as many characters of the first family are variable. Thus, the degree of elevation and upturning of caudal metatergal margins is strongly varied in hirudisomatids. Also, the telson width differs from broad and comprising nearly the entire caudal width to relatively narrow and comprising near half the caudal width. The collum overhangs the epicranium and the uppermost ocelli in hirudisomatids, but a similar collum state can be observed in some polyzoniids. Shelley (1995) has discussed variation in hirudisomatids. He considers the size and caudoventral position of the penes on the second male coxae as the only inviolable characters of the family Hirudisomatidae , in contrast to the dorsal position of the penes in the members of the family Polyzoniidae (at least in its Nearctic representatives). However, comparative examination the species of the Palaearctic genus Angarozonium from the collection of IBSS and the North American genus Petaserpes (all from Polyzoniidae ) at hand has revealed the caudoventral position of the penes in the first genus ( Figs 1, 2 ). Therefore, this character cannot be considered as sufficiently stable to distinguish the Palaearctic Polyzoniidae from the Hirudisomatidae . Thus, the main distinguishing characters of the Hirudisomatidae are the metatergal sculpture and the size of penes as well as the structure of the gonopods.

Figures

FIGURES 1 – 2. Penes and coxae 2, caudal view. 1, Petaserpes cryptocephalus (McNeill, 1887), male; 2, Angarozonium amurense (Gerstfeldt, 1859), male. Scale in mm, Mikhaljova del.