Theromyzon tessulatum ( Müller, 1774 )

Šatkauskienė, Ingrida & Rutkauskaitė-Sucilienė, Jurgita, 2022, The present state of the leech fauna (Annelida: Hirudinea) in Lithuania, Zootaxa 5115 (1), pp. 47-62 : 52-53

Theromyzon tessulatum ( Müller, 1774)

( Figures 4J–K )

Material examined: Molėtai (Nr. 4), n=1, 8.viii.2019; Šilalė (Nr. 8), n=1, 5.vii.2018; Mūšia (Nr. 14), n=1, 18.vi.2018; Maišia (Nr. 15), n=2, vii–viii. 2019; Šventoji (Nr. 20), n=1, 7.viii.2018; Siesartis (Nr. 23), n=1, 8.vii.2019; Akmena (Nr. 26), n=1, 2.2019;Šakarvai (Nr. 29), n=1, 20.viii.2018; Lūšiai (Nr. 30), n=1, 20.viii.2018.

Diagnosis: Body soft and gelatinous. 30 mm maximum length, and 3–4 mm width. General color of adult leeches is greenish-brown, dorsal surface is spotted by small black dots. Yellow warts scattered on dorsal surface and light–yellow spots locate on margins of body. Four pairs of eyespots arrange straight in head region ( Fig. 4J–K ). Four annuli between gonopores.

Habitat: Theromyzon tessulatum has been found mainly in ponds from May to August. Specimens bearing juveniles were observed in July. Juveniles of age of one week or more, appeared green due the intestine content ( Fig. 4K ).

Distribution: Species distributed in Holarctic regions. Based on number of findings in this study ( Table 1 , Fig. 1 ), it seems, that T. tessulatum is widespread, but not forming abundant populations. Usually, only solitary individuals occurred in each site.

Figures

FIGURE 1. Sampling stations of freshwater leeches in Lithuania.

FIGURE 4. Freshwater leeches in Lithuania: Theromyzon tessulatum an adult (J) and juvenile (K). Piscicola geometra anterior (L) and posterior sucker (M).