(Fig. 6D)
MATERIAL. — Specimen GIT 580-2: isolated tessera.
LOCALITY AND STRATIGRAPHIC HORIZON. — Same as specimens GIT 580-1, 3, 4, 6 and 7: locality (sample) 73, Tonnel’nyj Brook, south of De Long Strait, Chukotka; Lower Member (1) of Enmakaj Formation, Lochkovian.
DESCRIPTION ħe specimen is a diamond-shaped, 1.7 mm long tessera with a single central, narrow, elongate tubercle (c. 1.4 mm long). ħis tubercle has denticulated edges. Each denticulation is simple (undivided). Additionally, on each side of this central tubercle occurs a much smaller narrow tubercle (Fig. 6D). ħe base of the tessera is perforated by small foramina of the underlying (probably reticulated) layer. ħis tessera compares well with those of Lepidaspis serrata Dineley & Loeffler (1976: figs 74, 76, pl. 32: 6, 7), and especially with the tessera in their plate 32: 6, which bears a small lateral tubercle beside the main central denticulated one. However, because we have here a single tessera, it is difficult to compare with the great variability of shapes observed on Lepidaspis serrata tesserae (Dineley & Loeffler 1976), and so only tentatively assign GIT 580-2 to Lepidaspis.