Trigonops convexa Zimmerman. 1942, new species
Creators: name: Zimmerman, Elwood C.
Publisher: name: Zenodo
Year: 1942
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Curculionidae
Trigonops
Trigonops convexa

description: 8. Trigonops convexa, new species (pl. 1, <i>I;</i> fig. 1, <i>a).</i> Derm dark reddish brown to black; scaling subject to great variation, dorsmn varying from grayish white to coppery brown; pronotum usually with dark scales in front of elytral intervals 2 and 3; elytral marking variable, but usually with a patch of white squaniae at least on third interval at about middle or with a V-shaped fascia of white scales across elytra. <i>Head</i> rather closely punctured, punctures obscured by dense scaling, setae recumbent; eyes broadly convex, not protuberant, not sharply interrupting lateral cephalic outline, as long as or slightly longer than interocular breadth. <i>Rostrmn</i> with basal part between transrostral carina and basal suture convex to very strongly convex longitudinally, not depressed below transrostral carina, with a variable, longitudinal median carina, three fourths or more than three fourths as long as interocular breadth; declivitous apical part finely to moderately coarsely punctured in middle, more coarsely and densely toward sides and base, squamose and with erect or suberect setae at base. <i>Ante111zae</i> with scape longer than seven funicular segments, setae so curved that their apices touch or almost touch derm; funicle with lengths of segments as follows: (1, 1.3) (2, 1.2) (3 and 4, 0.9) (S, 6, and <i>7,</i> 0.8); club about as long as three preceding funicular segments, its first segment about three eighths longer than second. <i>Prothora.x</i> about as long as broad, broadest at or slightly behind middle; discal puncturation variable, the punctures comparatively fine to rather coarse, setae decumbent, arising from outer sides of punctures and extending across them toward median line; interstices often with low granules. <i>Elytra</i> more than three fourths as broad as long, twice as long as prothorax, broadly convex on sides from base to beyond middle thence sharply narrowed to apex; striae well defined, but not deeply impressed between punctures, not concealed by scaling, usually with polished granules bearing quite conspicuous setae at bases of punctures toward base; intervals flat or hardly convex on disk, the sixth usually distinctly more elevated and carinate behind, especially in males; scales angular, their surfaces minutely reticulate, closely appressed; setae rather short, slightly slanting or decumbent on disk. <i>Legs</i> with hind femora reaching to slightly beyond apex of fourth ventrite in female, to about apex of fifth in male, setae decumbent, not slanting distinctly away from derm; hind tibiae bristling with slanting setae, straight on outer margin. Sternum with prosternum one half as long between a coxal cavity and fore margin as between cavity and hind margin, intercoxal process about one fourth as broad as a coxa; mesosternum with side pieces densely squamose, intercoxal process coarsely punctate; metasternum between mid and hind coxae about two thirds as long as breadth of a mesocoxa, coarsely punctate in middle and there with long, slanting setae and scattered scales. <i>Venter</i> with first ventrite almost free from scales in middle, slightly flattened or tumid in female, distinctly flattened in male, coarsely punctate, setose as the metasternum; second ventrite denuded at middle near base, otherwise densely squamose; third and fourth ventrites punctate and setose from side to side; fifth ventrite densely punctate and setose and with few or no scales. Length, 4-6 mm.; breadth, 2-3 mm. Holotype male, Upi Trail, May 5, 1936, Usinger; allotype female, Machanao, June 30, Swezey; seven specimens taken at same time and place as holotype by Swezey, five by miscellaneous sweeping and two from ferns; 19 specimens with same data as allotype, but two from <i>Ficus;</i> two specimens from same locality, June 5, Usinger; two, same locality, one <i>from Iponioea pes-caprae,</i> June 4, and the other Aug. 6, Usinger; three, Ritidian Point, June 2, Usinger; five, Yigo, Nov. 13, Swezey; one, Dededo, Nov. 8, Swezey; three, Orote Peninsula, May 9, Bryan; two, Orote Peninsula, one Sept. 1, from <i>Premna,</i> the other, Sept. <i>27,</i> from <i>Sida,</i> Swezey; one, Upi Trail, May 5, Bryan; two, Sumay, in cultivated hedge of hibiscus, Oct. 31, Swezey; one, Fullaway labeled " Guam Island." This is a puzzling, variable, difficult species to describe. It is allied to <i>T. vulgaris</i> which it resembles in size, shape, and coloring, but it can be separated from that species by its much less convex eyes. Some specimens might be separated from small, abnormal specimens of <i>T. inusitata,</i> with difficulty but most examples are much smaller than those of <i>T. imisitata</i> and, together with the characters mentioned in the key, can be readily separated. This species varies greatly in size, shape, color, color pattern and structure. Two extreme individuals might almost be described as two species if found separately and if no series of specimens showing intergradation of details were available. In the National Museum material is a series of specimens which appear to be distinct from <i>T. conve.xa.</i> However, I have been unable to find satisfactory characters by which to separate them and have left them unnamed.
description: Published as part of <i>Zimmerman, Elwood C., 1942, Curculionidae of Guam, pp. 73-146 in Insects of Guam I, Honolulu, Hawaii :Bernice P. Bishop Museum</i> on pages 90-92, DOI: 10.5281/zenodo.5159964