Thisiomorphus Pic

Pollock, Darren A., 2016, Revision of Thisiomorphus Pic (Coleoptera: Mycteridae: Eurypinae) with descriptions of eleven new species from Central and South America and a key to genera of Neotropical Eurypinae, Zootaxa 4093 (3), pp. 301-322 : 303-304

Thisiomorphus Pic

Thisiomorphus Pic 1931: 31 ; Blackwelder 1945: 493; Pollock 2010: 693; Ivie & Pollock 2012: 10. Type species. Thisiomorphus latus Pic , by monotypy.

Original description (translated from Pic 1931: 31 by the author): “ Thisiomorphus n. gen. (fam. Lacconotinae ). This genus, near Thisias Chp. , which can be distinguished at first glance by the structure of the prothorax and the pygidium protruding posterior of the elytra, presents the following principal characters: fore coxae approximate and median coxae with trochantin, legs robust, tarsal claws appendiculate; antennae short and slender, with club of four articles; prothorax short and transverse, with weak lateral bead, vanishing anteriorly, and posteriorly bordered; body robust, very slightly pubescent; pygidium prominent. – This genus is established for the following new species.”

Redescription of genus. Body subparallel-sided, elongate oval or broadly oval (TL/GEW 2.02–3.05), flattened to slightly convex dorsally. Pubescence short, inconspicuous (most pronounced in T. osaensis ). TL 4.12– 7.90 mm; GEW 1.52–3.52 mm.

Head relatively short, slightly to moderately narrowed posterior of eyes; distance between posterior extent of eye and anterior margin of pronotum much less than length of one eye; eyes moderately large, hemispherical in some species, finely faceted, without intrafacetal setae; frontoclypeal suture not indicated; frontal furrows present, of variable length and depth, parallel or slightly convergent anteriorly; frons slightly elevated over very slightly concealed antennal insertions; labrum distinctly transverse, anterior margin slightly convex to slightly concave.

1. It is doubtful that all species of Loboglossa described by Pic and Champion are congeneric with L. variipennis Solier , the type of the genus

Antennae relatively short, extending posteriorly to near midlength of pronotum (in T. curticornis n. sp. slightly past anterior margin), not exhibiting obvious sexual dimorphism; scape and pedicel short, submoniliform; antennomeres 4–10 variable, from submoniliform (e.g. T. osaensis , T. curticornis ) to filiform, some species with vaguely indicated, subserrate distal club of 4 antennomeres; sensilla obvious on distal surfaces of antennomeres 5– 10 in some species (e.g. T. davidsoni ).

Mandibles relatively short, slightly asymmetrical, apically shallowly bidentate; inner, terebral teeth absent, represented by indentations or crenulations, especially on right mandible; left and right mandibular molae subequal in size, approximately subquadrate; prostheca distinct on both mandibles, nearly half the length of mandible; maxillae with inner lacinia slightly shorter than outer galea, both bluntly rounded and densely setose; maxillae with palpomeres elongate, 3-segmented, terminal palpomere variously securiform to slightly cultriform; mentum relatively short, labial palpi with terminal palpomere fusiform.

Prothorax subquadrate to distinctly transverse (GPW/PL 1.14–1.73); lateral pronotal margins parallel-sided (e.g. T. solisi ), convergent anteriorly (e.g. T. convergens ), to evenly arcuate (e.g. T. brasiliensis ); pronotal disc indistinctly to distinctly convex, with (e.g. T. brasiliensis ) or without broad, paired depressions; lateral carina absent, or at most vaguely impressed, posteriorly only; posterior margin of pronotum with distinct, relatively narrow but deep groove, ending laterally in slightly widened pits; prosternum anterad procoxae relatively short, intercoxal process narrow, elongate, extending to at least one-half length of procoxae, not broadened distally; procoxae rounded to slightly elongate; cavities broadly open, protrochantins concealed.

Mesothorax. Elytra moderately ovate, ovate-elongate, to distinctly elongate; disc flat to moderately convex, upper surface evenly punctate/setose, setae mostly decumbent, but with a few scattered, erect setae; apical elytral patch present, conspicuous or inconspicuous dorsally (in intact specimens); each epipleuron narrow through most of its length, but distinct to very nearly the elytral apex; mesosternum with posterior intercoxal process elongate, subparallel-sided, extended posteriorly to past one-half length of mesocoxae; mesocoxae completely separated, trochantins exposed; coxal cavities partially closed laterally by inner margin of mesepimera.

Metathorax. Metasternum large, convex, with distinct discrimen; intercoxal process distinct, in contact with, or slightly overlapping mesosternal process; metendosternite with relatively wide stalk; anterior tendons attached to anterior surface of metendosternite body; laminae (lateral extensions) relatively short, rounded to somewhat angulate.

Wing fully developed, with wing membrane beyond closed radial cell moderately short; wing lightly to moderately darkly pigmented; 3 MP veins reaching hind wing margin, proximal to CuA + AA; pigmented flecks present, near junction of RP and MP, and near radial cell.

Legs well developed, similar in relative size and shape on all thoracic segments; legs relatively slender, femora slightly deepened at midlength; tibiae straight, subequal in length to femora; tibial spurs very short, inconspicuous; tarsi 5-5-4, simple ventrally except penultimate tarsomere distinctly broadened; tarsal claws with large, blunt basal tooth.

Abdomen with all ventrites freely articulated, uniformly punctate and setose; male sex patch present on second ventrite, consisting of relatively small, longitudinally ovate patch of thickened, posteriorly directed setae.

Male genitalia ( Figs 13–20 ) relatively short, stocky, median lobe oriented dorsad tegmen; sternite 9 forming ring-like sclerite; tegmen of two distinct parts; basale broad, deeply emarginate proximally; apicale divided into two separate parameres, shorter than basale (along lateral margin); inner margins of parameres relatively straight or slightly emarginate/sinuate distally, apices distinctly hooked medially; penis relatively stout, distinctly longer than tegmen; ventral surface emarginate; dorsal side subquadrate basally, sides somewhat explanate or “flanged”; apex of penis bluntly triangular to slightly bulbose.

Female genitalia with relatively short, lightly sclerotized ovipositor; coxites short, multi-segmented, with short setae; distal segment darker, more sclerotized than remainder of coxite; valviferal and proctigeral baculi well developed; coxital baculi present, situated distinctly distad ovipositor midlength; spiculum distinct, long, exceeding length of segment 8; bursa copulatrix small to moderately large, separated from vagina by narrow constriction.

Natural history. No biocontextual information has been published for any species of Thisiomorphus ; this is not surprising, as there was only one previously described species, based on a single specimen. The only data available have been gleaned from specimen labels, and even that is rather scant, regarding natural history of adult Thisiomorphus . For several species ( T. osaensis , T. inaequalis , and T. caeruleus ) the only relevant data indicate capture in a Malaise trap. Specimens of T. solisi have been captured in both Malaise and flight intercept traps. The greatest detail in relevant natural history data is in that of T. festivus . In addition to being collected by Malaise trap, and in primary and secondary forest, there are three associations with plants. There is a generic “palm” association on one of the specimen labels; two other species are also indicated: Astrocaryum alatum Loomis (underside of leaf) and Raphia taedigera (Mart.) Mart. (on frond). Both species are members of the palm family ( Arecaceae ), and, although there are only two records, they may indicate an association of T. festivus with palms. Immature stages of Thisiomorphus remain unknown; however, based on known larvae of other genera of Eurypinae , it seems likely that larvae are subcortical inhabitants of dead trees or within dead vegetation (see Pollock 1995; Pollock et al. 2000).

Figures

FIGURES 13 – 20. Male genitalia of Thisiomorphus species. 13. T. andrewsi, n. sp.; 14. T. brasiliensis, n. sp.; 15. T. caeruleus, n. sp.; 16. T. curticornis, n. sp.; 17. T. festivus, n. sp.; 18. T. inaequalis, n. sp.; 19. T. osaensis, n. sp.; 20. T. solisi, n. sp..