Operclipygus dytiscoides, Caterino, Michael S. & Tishechkin, Alexey K., 2013

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Operclipygus Marseul (Coleoptera, Histeridae, Exosternini), ZooKeys 271, pp. 1-401 : 92-93

Operclipygus dytiscoides sp. n. Figs 24 A–CMap 8

Type locality.

ECUADOR: Orellana: Tiputini Biodiversity Station [0°38'S, 76°9'W].

Type material.

Holotype female: "ECUADOR Napo Region 5 –25.ix.00” / "Tiputini Research Station 220m 0°38'0"S, 76°9'0"W" / "BM2000:194 D.J.Inward K.A.Jackson" / "Caterino/Tishechkin Exosternini Voucher EXO-00017", specimen gold coated for SEM (BMNH).

Other material.

PERU: Cusco: 1 female: Villa Carmen Field Station, 12.89250°S, 71.41917°W, 24-26.v.2011, FIT (SEMC).

Diagnostic description.

Length: 1.90 mm, width: 1.59 mm; body rufo-piceous, elongate oval, prolonged anteriorly, depressed, coarsely punctate over most of prono tum, less strongly so on elytra; head deeply recessed into prothorax at rest, frons broad, punctate, frontal striae straight, divergent between eyes, with central portion transverse, complete; epistoma weakly depressed, apical margin shallowly emarginate; labrum two-thirds as long as wide, apical margin outwardly rounded; mandibles strong, left with small basal tooth, right with stronger one; prothorax with sides convergent, straight in basal two-thirds, abruptly narrowed, sinuate in apical third; lateral marginal pronotal stria present along side, ending freely in a small inward hook in anterior corner; lateral submarginal stria close to marginal, strongly impressed along inner edge, bent inward and continuous with anterior marginal stria across front, marginal bead broad and slightly elevated; pronotal disk strongly punctate throughout, punctures becoming smaller and sparser anterad, lacking plicae or prescutellar impression; median pronotal gland openings difficult to discern among punctures but present, simple, about head-width apart, nearly one-fourth pronotal length behind anterior margin; elytra with two complete epipleural striae, with all dorsal striae elevated, sides of each stria subcarinate with relatively broad, flat inner depression; all striae complete except inner subhumeral, barely abbreviated at apex; elytral disk with numerous small punctures in elytral intervals; prosternal keel trunctate posteriorly, narrowing strongly toward presternal suture, carinal striae fragmented to absent; lateral prosternal striae curving inward toward front; prosternal lobe with strong median ridge continuous with prosternal keel, apical marginal stria interrupted at middle where ridge reaches edge; mesoventrite shallowly emarginate at middle, marginal stria interrupted at middle by strongly arched meso-metaventral stria; postmesocoxal stria arched to mesepimeron, lateral metaventral stria extending nearly to metacoxa, meeting recurrent stria, which extends anterad to meet anterior part of metepisternum; meso- and metaventral disks, as well as 1st abdominal ventrite with numerous punctures separated by about their widths; 1st abdominal ventrite with two complete lateral striae; protibiae very strongly toothed, each tooth with a long spine; all tarsi with apical tarsomere expanded, laterally flattened, pretarsal claws small, straight, parallel, approximate, extending from ventral corner of tarsomere (rather than apex); propygidium transverse, about half length of pygidium along midline, with intermixed punctures of various sizes, gland openings present in anterolateral corners, small; pygidium with uniform small punctures throughout, lacking apical marginal stria. Male not known.

Remarks.

This species is more elongate, especially markedly in pronotal shape, than other species of the group (Fig. 24A). It also lacks an apical marginal elytral stria, which the following two species have.

Etymology.

This species is named for its somewhat diving beetle-like body form.