Notocupes caudatus Ponomarenko, 1966

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 : 505-507

Notocupes caudatus Ponomarenko, 1966

( Figs 5–7 )

Material. Holotype PIN, 1989/3002, part and counterpart of full body, Baissa locality; Lower Cretaceous.

Diagnosis. Lateral keels on vertex well defined. Anterior pronotal angles slightly protruding; sides of pronotum dentate. Elytra with elongate-oval cells; maximum of cells per row 27. Epipleuron wide along entire length. Terminal abdominal sternite VII 3.1 times longer than VI.

Description. Body length/width ratio 2.1. Cuticular tubercles round, evenly distributed, on most parts diameter ca. 0.03 mm and density 656 tubercles per mm² ( Fig. 5 E-a); larger on terminal abdominal sternite VII and in depressions of sternites III–VI, diameter 0.05 and density 211 ( Fig. 5 E-b). Distance between smaller tubercles 0.01– 0.02 mm, between larger ones 0.02–0.03 mm, i. e., less than diameter of tubercles. Elytra without color pattern.

Head: transverse, length 1.8 mm, exceeding width. Body length/head length ratio 6; neck constriction absent. Eye diameter 1.4 times exceeds head length in front of eyes and 1.2 times behind eyes. Head retracted within pronotum to level of posterior margin of posteromesal (Р3) protuberance. Vertical region divided by longitudinal furrow; lateral keels on vertex well defined. Posteromesal protuberance rounded. Head width approximately 1.2 mm; head width/ocular diameter ratio 2. Labrum large, rectangular. Mandibles with single preapical tooth; basal third curved. Praementum small, rounded. Antennae attached near anterior margin of eyes; antennal insertions covered from above by supraantennal protuberance (Р1). antennal furrows on head absent. Scapus enlarged, curved, 0.6 mm long, 0.3 mm wide; length of scapus/length of pedicellus ratio 1.6. Antennomeres 1–3 slightly widening distally.

Pronotum: length 2.1 mm, width 3.3 mm; width/ length ratio 1.6; maximum width/width of anterior margin ratio 1.5. Anterior angles slightly protruding forward, is half as long as the temples; posterior margin rounded, sides dentate; maximum width at posterior margin. Pronotal disk with pair of bean-shaped protuberances, slightly narrowing anteriorly, with median furrow between them. Notopleural and pleurosternal sutures not clearly visible.

Scutellar shield: somewhat rhomboid.

Elytra: cells rounded, not elongated, almost circular on distal half. Single row of large cells presents in field I, other fields with two rows of cells; field II with 20 cells, fields III and IV with about 27, field V with 19, field VI with 25, and field VII with 3. Number of cells rows 10 on dorsal side of elytra and 1 on epipleuron. Maculae around cells and within walls of cells present, with number varying from 4 to 8. Distal half of field I with 5 or 6 maculae around one cell, distal portion of elytron with 4 or 5 maculae per cell. Middle portion of field IV usually with 6 maculae around one cell, anterior and preapical areas with 5. Field V with 6 maculae around one cell, but anterior and preapical areas with 5 and 4, respectively. Cells of field VI mostly with 5 or 6 maculae, but some cells on anterior third with 7 or 8. Field VII with cells surrounded by 5 maculae. Cells occupy little more than half distance between veins, not reaching lateral edges of fields. Elytral length/width ratio 3; elytra slightly extending beyond abdominal apex posteriorly. Veins 2 and 3 most likely with common stem; vein 2 running along epipleural margin; vein 3 straight; veins 4 and 5 merge five cells anterior to elytral apex; 2 and 3 reach elytral apex. Elytral maximum width at midlength. Epipleural margin curving slightly towards the apex; epipleuron wide, scarcely narrowing at elytral apex. Epipleural width near elytral base/width near elytral apex ratio 1.3. Elytral base and apex rounded. Humeral bulge not prominent. Elytral width/pronotal width ratio 2.

Metaventrite: length about 1.8 mm, width at posterior margin 2.8 mm. Width of posterior margin of metaventrite/ length ratio 2.3. Ratio of combined length of meso- and metaventrite versus length of abdominal 0.6.

Abdomen: length 6.5 mm. Relief of sternites very prominent. Apical sternite and depressed portions of sternites III–VI with sculpture of large tubercles. Abdomen narrowing posteriorly, starting from sternite VI, abdominal apex pointed. Length ratio of sternites: 2.1:1:1:1:3.1. Width of apical sternite/length ratio 1.4.

Legs: pro- and mesocoxa not visible; metacoxae distinctly narrowed laterally, their length is 0.6 mm, width 2 mm, posterior margin not reaching midlength of ventrite 1 (abdominal sternite III). Metacoxal width 3.3 times exceeding length.

Measurements. Length— 14 mm, width— 6.7 mm, elytral length— 10.2 mm, elytral width— 3.4 mm.

Remarks. The width of the head is difficult to estimate due to its tilted position. It is mentioned in the original description that the pronotal posterior angles are protruding posterolaterally ( Ponomarenko, 1966a). However, the left side of the pronotum is not preserved and the sharp angle with the pronotal posterior margin is formed by its remnants. The right side of the pronotum is also tilted and lacks protruding posterior angles. We reinterpret a previously described transverse protuberance along the pronotal posterior margin as internal sculpture along the pronotal posterior margin visible in ventral perspective.Structures, interpreted as small procoxae in the original description are in fact depressions on the backside of the pronotum. The species is similar to N. excellens in the presence of dentate lateral edges of the pronotum.

Figures

FIGURE 5. Notocupes caudatus (PIN, 1989/3002). A, Wetted with 95% ethanol. B, Details of head. C, Dry (black rectangle indicate area on figure D). D, Elytral cells. E, Interpretative line drawing, dorsal aspect. Abbreviations: l.ke, lateral keels; P1, supraantennal protuberance; P2, supraocular protuberance; P3, posteromesal protuberance. All pictures are mirrored.

FIGURE6. Counterpart of Notocupes caudatus (PIN,1989/3002).A, Counterpartwetted with 95% ethanol.B, Dry.C, Interpretative line drawing, ventral aspect.

FIGURE 7. General scheme of Notocupes caudatus elytra.