Oxyporus Fabricius, 1775

Tokareva, Alexandra, Solodovnikov, Alexey & Konstantinov, Fedor, 2020, Immature stages and biology of the enigmatic oxyporine rove beetles, with new data on Oxyporus larvae from the Russian Far East (Coleoptera: Staphylinidae), Acta Entomologica Musei Nationalis Pragae 60 (1), pp. 245-268 : 250

Genus Oxyporus Fabricius, 1775

Description of third instar larva. Body white, with thoracic and abdominal terga yellow, grey, brown or without pigmentation, rather large (6.0 to 20.9 mm), elongate, slightly dorso-ventrally curved, parallel-sided.

Head. Yellow to brown or without pigmentation, prognathous, oval. Ecdysial lines distinct, Y-shaped, with lateral arms complete, running to bases of antennae. Epicranium with a pair of six stemmata in two vertical rows of unequal length ( Figs 5, 6 ). Setation composed of simple setae, microsetae less than ¼ length of average seta, and campaniform sensilla. Setae arranged in frontal dorsal and frontal lateral rows (Fd, Fl), epicranial dorsal and epicranial lateral rows (Ed, El), temporal rows (T), and lateral rows (L). Campaniform sensilla (c. s.) arranged in stable pattern, corresponding with setal rows. Antennae short, three-segmented: antennomere I elongate, narrowed towards middle, asetose, with four campaniform sensilla; antennomere II trisetose, with one campaniform sensillum, tubercle-like sensory appendage with distinct basal collar (SA1), and narrow simple conical sensory appendage (SA2) ( Fig. 41 ); antennomere III small, with three apical setae and superior group of small sensilla consisting of one thickened membranous solenidium (IIIs3), two narrow spiny solenidia (IIs1, IIs2), and one microseta (IIIams), as in O. procerus ( Fig. 41 ). Nasale serrate; dorsal nasal setae include labral lateral and labral lateral setae (Ld, Ll) ( Figs 45, 46 ). Epipharynx with multiple microtrichia and median furrow. Mandibles broad basally, flattened laterally, apically bicupsidate, with serrate lobes, prostheca absent. Maxillae with small triangular precardial sclerite; cardo triangular, with one seta; stipes short, with three setae and one campaniform sensillum; mala trilobed, with two non- -articulated usually short wide spines on inner and middle lobes, and one non-articulated spine, two articulated setae and two campaniform sensilla on outer lobe. Maxillary palpi three-segmented; palpifer divided into two membranous parts with one seta on proximal part and seta and campaniform sensillum on distal part; palpomere I asetose with one campaniform sensillum; palpomere II with two setae and two or one campaniform sensillum; palpomere III asetose with campaniform sensillum. Labium fused to hypopharynx, forming membranous flexible socket, with two setae on submentum, two setae and two microsetae on mentum, and group of usually two setae and campaniform sensilla (Pv1, Pv2, Pc) on prementum at base of each labial palpus; labial apex with two setae and half-ring of tiny microtrichia ventrally on hypopharyngeal part; labial palpus two-segmented, asetose.

Thorax. Tergites transverse, moderately sclerotized. Pronotum broadly oval, with narrow membranous area along midline; setation with anterior (A), discal (D), lateral (L), and posterior (P) rows of setae in each half. Membrane anterior to pronotum in some species with four microsetae M1–M4 or some of them. Mesonotum transverse, with anterior, lateral and posterior rows of setae. Membrane anterior to mesonotum usually with four microsetae M1–M4. Metanotum transverse, with anterior, lateral and posterior rows of setae. Membrane anterior to metanotum with four or less microsetae M1–M4.

Legs. All legs with uniform setation. Coxa, trochanter, femur, tibia, and tarsungulus with 18, eight, eight, nine and two setae, respectively.

Abdomen. Tergites transverse. Membrane anterior to abdominal tergum I with two or three microsetae. Tergite IX with one or two pairs of microsetae anteriorly and up to four pairs of average length setae posteriorly. Urogomphus two-segmented; segment I with four to six setae on apical part; segment II narrower, with one short ventral seta and two longer apical setae. Pygopod or abdominal segment X slightly tapered from base to apex, setation of 16–24 setae, usually asymmetrically arranged.

Figures

Figs 1–6. Third instar larvae and adults of Oxyporus spp. general view.1 – imago of O. maxillosus Fabricius, 1775, dorsal view; 2 – imago of O. procerus Kraatz, 1879, dorsal view; 3 – imago of O. (P.) melanocephalus Kirschenblatt, 1938, dorsal view; 4 – larva of O. maxillosus, lateral view; 5 – larva of O. (P.) melanocephalus, lateral view; 6 – larva of O. (P.) melanocephalus, head and thorax in ventral view.

Figs 39–44. Scanning electron micrographs of larva of Oxyporus procerus Kraatz, 1879. 39 – campaniform sensilla and setae of nasale; 40 – posterior epicranial group of sensilla; 41 – antennomeres II and III, apical sensorial complex; 42 – premental group of sensilla; 43 – campaniform sensillum, segment II of maxillary palpus; 44 – thoracic tergite I, lateral view.

Figs 45–52. Third instar larva of Oxyporus (P.) melanocephalus Kirschenblatt, 1938, head morphology. 45 – head, dorsal view; 46 – head, ventral view; 47 – antenna, dorsal view; 48 – mandible, dorsal view; 49 – maxilla, dorsal view; 50 – labium, dorsal view; 51 – labium, lateral view; 52 – maxilla, ventral view.