Zygadenia alexrasnitsyni, STRELNIKOVA & YAN, 2021

STRELNIKOVA, OLESYA D. & YAN, EVGENY V., 2021, Redescriptions of beetles of the Notocupes generic complex (Coleoptera: Archostemata: Ommatidae) from the Lower Cretaceous of Buryatia, Palaeoentomology 4 (5), pp. 499-514 : 508-509

Zygadenia alexrasnitsyni sp. nov.

( Fig. 11 )

Material. Holotype PIN, 1989/2989, part and counterpart of left elytron, Baissa locality; Lower Cretaceous.

Etymology. Named for Prof. Alexandr P. Rasnitsyn.

Diagnosis. Elytral cells rounded; maximum of cells in one row 38; no pairs but seven triplets of cells near elytral base. Epipleura with incomplete row of cells strongly narrowing towards posterior end of elytra and reaching elytral apex. Maculae around cells and within walls of cells present. Elytral apex protruding as tonguelike extension, slightly pointing laterad.

Description. Elytral cells rounded. Field I with partially preserved row of 7 cells, other fields with double cell rows; field II with 31 cells, narrowing posteriorly and then merging with epipleural edge; cells therefore lacking in this interval; fields III and IV with 38 cells, field V with 29, field VI with 37 cells, and field VII with 5 cells. Number of cell rows 10+1.

Maculae around cells and within walls of cells present, number varying from 4 to 7. Field I with 4 or very rarely 5 maculae around one cell; field II usually with 5 maculae, but with 7 in the midlength region of the elytron; cells of field III mostly with 5 maculae, at midlength with 6, and 4 or 6 closer to elytral apex; usually cells with 6 maculae surrounded by cells with 4; field IV usually with 5 or 6 maculae around one cell; number of cells varying between 5 and 7; not arranged in pairs but in triplets (7) near elytral base. Fields V and VI with cells with different number of maculae: usually 5, but 4 near elytral base and 6 or 7 near apex. Field VII with two cells with 4 maculae and three with 5. Cells occupy half distance between veins and do not reach lateral edges of fields.

Elytral length/width ratio 3. Veins 2 and 3 with common stem, four cells posterad anterior elytral edge; vein 2 running along epipleural margin; vein 3 slightly curved; veins 4 and 5 merge six cells anteriad elytral apex. Elytra reach maximum width around basal third. Basal third of epipleuron wide, then abruptly narrowing and reaching elytral apex without changing width. Epipleural width near elytral base/ epipleural width near apex ratio 2,8.Elytral base rounded and humeral bulge not prominent. Elytral apex extended as tongue-like protrusion.

Measurements. Elytral length— 14.7 mm, width— 4.8 mm.

Remarks. ItwaspointedoutbyPonomarenko(1966a) that this species is similar to N. excellens . However, our study revealed differences: the cells of N. excellens are not round, but rectangular with rounded angles, without maculae; the epipleural (outer) margin is dentate near the elytral base and the epipleuron much narrower and without cells; the humerus is not prominent and the elytral base is straight and less rounded. Z. alexrasnitsyni sp. nov. is distinctly larger than all Notocupes species from Baissa locality and displays a peculiar character: the presence of cell triplets at the base of field IV. This feature was previously unknown in Zygadenia .

Figures

FIGURE 11. Holotype (PIN, 1989/2989) of Zygadenia alexrasnitsyni sp. nov. A, General view. B, Interpretative line drawing of the holotype. Dotted lines indicate epipleural boarder.