Trigonorhinus limbatus
Creators: name: Janicki, Julia
name: Young, Daniel K.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Anthribidae
Trigonorhinus
Trigonorhinus limbatus

description: Trigonorhinus limbatus (Say)   
(Fig. 27–28)  
 Anthribus limbatus Say 1826: 250.   
 Brachytarsus plumbeus Leconte 1876: 406.   
 Brachytarsus vestitus Leconte 1876: 406.   
 Brachytarsus naviculus Jordan 1907: 379.   
 Brachytarsus limbatus (Say); Blatchley and Leng 1916: 40.   
 Brachytarsoides limbatus (Say); Pierce 1930: 30.   
 Brachytarsoides rufodorsalis Dethlefsen 1954: 58.   
 Brachytarsoides minor Dethlefsen 1954: 58.   
 Brachytarsoides quadratus Dethlefsen 1954: 59.   
 Brachytarsoides quadratus ssp. nigrinus Dethlefsen 1954: 60.   
 Trigonorhinus limbatus (Say); Valentine 1957: 9.   
 Description. Length 1.8–3.2mm (head excluded). Integument black to dark reddish-brown, legs light reddish-brown. Vestiture consisting of white to light brown setae; pronotal setae pale grey or brown, in spots or intermixed with darker brown; elytral discal setae white, white and light brown intermixed, or entirely light brown, with light brown setae often in small, scattered spots. Rostrum moderately prolonged, narrowed apically, medial 1/3 prolonged apically; surface finely punctate. Frons weakly convex, weakly transversely impressed below eye level, surface finely punctate. Pronotal width 1.2X length, widest at basal angles; sides distinctly arcuate, strongly converging to narrowly rounded apical margin; disc evenly and strongly convex, weakly and transversely impressed before transverse carina, transverse carina basal, very weakly arcuate, acutely elevated; surface shining, with shallow, sparse punctures, interpunctural space punctulate or minutely reticulate. Elytral length 1.2X width, sides evenly and weakly arcuate to broadly rounded apex; disc evenly convex; striae weakly and narrowly impressed, with small, deeply impressed punctures; interstriae 3.0–4.0X strial width, minutely reticulate-granulate.   
 Diagnosis. Trigonorhinus limbatus can be distinguished from other Trigonorhinus species by its diffuse color pattern consisting of white to light brown setae, and by the pronotum possessing a shallowly emarginate base that is arcuate opposite the scutellum.   
 Natural history. Adults breed in the heads and stems of various flowers in Asteraceae, especially in those of Helenium. Specifically, they have been recorded on sneeze weed, Helenium autumnale. According to Howden (1992), Valentine observed that adult females use the toothed ovipositor to simply push aside parts of a composite flower head, or they may oviposit in stems. A Wisconsin series was recorded “mating and perhaps feeding on flowers of Helenium autumnale ”.   
 Phenology. In Wisconsin, adults have been collected June – August.   
 Collecting methods. The 31 Wisconsin specimens examined during this study from five counties represent a NEW STATE RECORD. Most specimens were hand-collected from H. autumnale.
description: Published as part of Janicki, Julia & Young, Daniel K., 2017, Nemonychidae and Anthribidae of Wisconsin (Coleoptera: Curculionoidea), pp. 1-36 in Insecta Mundi 2017 (579) on pages 19-20, DOI: 10.5281/zenodo.5169237