Tropiphorini

Spanton, Timothy G. & Anderson, Robert S., 2016, A Taxonomic Revision of Weevils of the Genus Panscopus Schönherr (Coleoptera: Curculionidae: Entiminae: Tropiphorini), The Coleopterists Bulletin (mo 15) 70, pp. 1-86 : 5-8

Tribe Tropiphorini

Diagnostic Characters of Adults. Adult representatives of the tribe Tropiphorini are adelognathan weevils with a scar on the mandibles at the point of attachment of the deciduous cusp, 10 or fewer setae on the ventral surface of the prementum (in most genera three pairs or fewer), and the scrobes relatively indefinitely delineated on the dorsal and ventral margins, so that the scape passes over the middle of the eye or as low as the bottom quarter of eye when resting next to head.

Within the New World fauna, representatives of two other tribes, the Ophryastini and the Premnotrypini, somewhat resemble the Tropiphorini in that they are all adelognathous, possessing a scar on the mandible, and have postocular lobes on the anterior margin of the prothorax. Members of the Ophryastini and the Premnotrypini are distinguished by the clearly delineated scrobes which direct the scape ventrally, below the eye. In addition, most ophryastine weevils possess approximately 15 setae on the ventral surface of the prementum (fewer in some species) and have the scape and funiculus of the antenna and dorsal margin of tarsomeres 1–3 clothed with decumbent to appressed, generally broad, imbricate scales.

KEY TO ADULTS OF THE GENERA

OF TROPIPHORINI OF NORTH AND CENTRAL AMERICA

The following key is based largely on that of

Kissinger (1964), with some taxa removed and some added, to reflect the genera included in the tribe Leptopiini (= Tropiphorini ) in O’ Brien and Wibmer’ s (1982) checklist of weevils of North and Central America. The genera added include Trichalophus LeConte (including Acmaegenius LeConte , now a junior synonym of Trichalophus ), Plinthodes LeConte , Triglyphulus Cockerell , and Lepidophorus Kirby (including Vitavitus Kissinger , now a junior synonym of Lepidophorus ), all of which were included in the separate subfamily Alophinae by Kissinger (1964) and by Alonso- Zarazaga and Lyal (1999). The Mexican genus Amphidees Schönherr as well as the more recently described Leptopinara O’ Brien and Connatichela Anderson are also included. Recognition of the genus Amphidees remains problematic, as there are clearly unrecognized synonymies involving species of Amphidees , Crocidema Van Dyke , and Dyslobus LeConte. Future study of these genera should result in redefinition of genus-group limits.

The monobasic genus Synosomus Jekel (based on Synosomus geonemoides Jekel, 1858 ) remains an enigma. According to Sharp (1891), the holotype has been lost from the BMNH, and no other specimens of this taxon are known. Synosomus , therefore, is not included in this key.

1. Antennal funiculus and dorsal portion of tarsomeres 1–3 with decumbent, usually broad scales............................... 2

1′. Antennal funiculus and dorsal portion of tarsomeres 1–3 without decumbent, broad scales, but with more or less erect, setiform or narrowly elongate scales, or tarsi with few broad scales.................... 5

2(1). Rostrum trisulcate; hind coxae separated by distance at least twice width of coxa; elytral striae not distinct, each elytron dorsally with 2 coarse, irregular, longitudinal costae and binodose at apical fourth ..... Rhigopsis LeConte

2′. Rostrum not trisulcate, elytra not nodose at apical fourth........................................ 3

3(2′). Fine pubescence absent from ventral surfaces of tarsal segments; both sexes with 3 rd tarsal segment slightly if at all wider than 2 nd; postocular lobes distinct; antennal scrobes shallow and markedly widened posteriorly..... Cimbocera Horn

3′. Fine pubescence at apices of 3 rd tarsal segment; 3 rd tarsal segment usually distinctly wider than 2 nd, especially on males...........................................4

4(3′). Postocular lobes prominent; antennal scrobe shallow and markedly widened posteriorly; rostrum not continu- ous with frons, separated by transverse impression .... Paracimbocera Van Dyke

4′. Postocular lobes small; antennal scrobes deep and only slightly widened posteriorly; rostrum continuous with frons...... .................................... Miloderes Casey

5(1′). Metepisternal suture distinct, at least in basal half, complete, or obliterated; if obliterated, metepisternum with finer, smaller, and sparser scales than metasternum ......................................... 6

5′. Metepisternal suture obliterated entirely or in large part at least in basal half; metepisternum and metasternum with scales similar in coarseness, size, and density ................................................ 12

6(5). Scar of mandible very small, not obvious, absent in some species; rostrum continuous with frons, not separated by distinct transverse impression (some Plinthodes with slight impression) ( Alophinae auctorum) ................ 7

6′. Scar of mandible large, round or subcircular; dorsal margin of scrobe indistinct posteriorly; scape resting on eye when retracted next to head; rostrum separated from frons by distinct transverse impression...............................11

7(6). Scar absent from mandible; scrobes not sharply defined posteriorly, scape directed over middle of eye; smaller beetles, length 2.75–5.00 mm............. ......................... Lepidophorus Kirby

7′. Dorsal margin of scrobe sharply defined; scape directed below eye or over lower portion of eye; large, more robust beetles, length> 11 mm ...................................... 8

8(7′). Tarsi setose ventrally, 3 rd segment with pair of brush-like pads toward apex; rostrum finely sulcate, sulcus obsolete apically ................................................... ........... Trichalophus LeConte (in part)

8′. Tarsal pubescence brush-like on ventral surface; rostrum with deeply impressed lateral sulci ........................................... 9

9(8′). Anterior margin of eye separated from rostrum by deep fine groove extended between lateral sulcus and scrobe ........ ....................... Triglyphulus Cockerell

9′. Anterior margin of eye not separated from rostrum by groove...................10

10(9′). Elytral striae very coarsely punctate; pronotum more or less sulcate along mid-line ............... Plinthodes LeConte

10′. Elytral striae rather finely punctate; pronotum in part carinate along mid-line ............ Trichalophus LeConte (in part)

11(6′). Ventrite 2 longer than 3 and 4 combined, suture between ventrites 1 and 2 obliterated medially; 1 st segment of tarsus 1 dorsally with sparse round scales ........................................ Adaleres Casey

11′. Ventrite 2 not longer than 3 and 4 combined, suture between ventrites 1 and 2 deep, straight; 1 st segment of tarsus 1 without round scales on dorsal surface .............................. Dyslobus LeConte

12(5′). Frons distinctly narrower than rostrum at base; ventrite 2 at middle more than twice as long as ventrites 3 and 4 combined; tibia 3 with corbel open; scrobe not clearly defined posteriorly............... ............................. Dirotognathus Horn

12′. Frons not narrower than rostrum at base; ventrite 2 distinctly less than twice as long as ventrites 3 and 4 combined ....................................................... 13

13(12′). Tarsal claws connate at base; scape directed below eye ............................... ...................... Connatichela Anderson

13′. Tarsal claws free; scape directed over eye....................................................14

14(13′). Elytra with rows of large, coarse pits, each covered by a round or oval scale larger than surrounding scales; elytra of most specimens with sparse, coarse, erect setae; prementum with 2 setae or none .............. Panscopus Schönherr

14′. Each puncture of elytral striae either with fine seta, apparently glabrous, or punctures small and fine; prementum, in most taxa, with more than 2 setae on ventral surface.............................15

15(14′). Scape of antenna with at least a few flat scales..........................................16

15′. Scape of antenna without flat scales, either with suberect fine setae, or suberect, coarse, clavate, scale-like setae ..................................................... 23

16(15). Tibia 3 with corbel open; body usually with crusty coating, with long erect, sparse, spatulate setae; dorsal margin of scrobe indistinct posteriorly, scape passing over middle of eye .................. ............................. Phyxelis Schönherr

16′. Tibia 3 with corbel closed (may be broadly and distinctly closed, or narrowly and indistinctly closed)..........17

17(16′). Elytra with long, fine, erect setae, each seta about 5 times as long as diameter of adjacent scale; elytral scales flat, discrete, non-overlapping; tibia 3 with corbel distinctly closed, corbel plate clothed with flat, round scales ............ ................................ Diamimus Horn

17′. Elytra without erect setae ( Orimodema Horn ) or with stout bristles not more than 3 times as long as diameter of scales ( Dichoxenus Horn ); tibia 3 with corbel closed at least narrowly so....18

18(17′). Corbel narrowly and indistinctly closed, with scales on corbellar area................... ............................ Amphidees Schönherr ( A. longulus Sharp )

18′. Corbel distinctly closed, without scales on corbellar area ................................ 19

19(18′). Body elongate in form; elytra without erect setae, scales of elytra not overlapping; in dorsal view, lateral margins of rostrum distinctly convergent from base at anterior margin of eye to about the middle, thence nearly straight to articulation of antenna....................... .................................. Orimodema Horn

19′. Body shorter and stouter in form; elytra with sparse, erect bristles; in dorsal view, lateral margins of rostrum slightly, evenly convergent from base at anterior margin of eye to point of articulation of antenna ................................20

20(19′). Sternum VIII of female markedly compressed in apical region, vertical dimension much greater than horizontal dimension....................................21

20′. Sternum VIII of female shovel-shaped, with broad, laterally expanded process in apical region.................................22

21(20). Elytra with non-overlapping scales, on dorsal surface with short, erect, clavate setae; scape densely scaly...................... ............................... Paranametis Burke

21′. Elytra with striate, overlapping scales; elytral setae thin, slightly flattened; scape sparsely scaly.......................... ........ Amphidees Schönherr (in part)

22(20′). Scape densely scaly; elytral setae blunt apically; elytral scales dense, overlapping and decumbent; ventral margin of scrobe clearly defined; corbel of tibia 3 very narrowly closed to open ............. .................................. Dichoxenus Horn

22′. Scape mostly setose with a few broad scales; elytral setae fine, acute; elytral scales discrete, non-overlapping, flat; ventral margin of scrobe poorly defined; corbel of tibia 3 distinctly closed ........... ........................................ Anametis Horn

23(15′). Basal margin of elytra produced markedly and abruptly into perpendicular cliff before margin with sclerites covered by prothorax.............................24

23′. Elytra without distinct basal margin, evenly rounded to sclerites covered by prothorax (or elytra without erect setosity, Melanolemma Van Dyke ); dorsal margin of scrobe indistinctly defined posteriorly..........................26

24(23). Dorsal margin of scrobe not defined posteriorly, scape passes over middle of eye; corbel of tibia 3 open; body without erect setae or scales................. ...................... Tropiphoru s Schönherr

24′. Dorsal margin of scrobe clearly defined posteriorly, scape directed over lower portion of eye or below eye; corbel of tibia 3 narrowly closed ...................... 25

25(24′). Body with erect fine setae, usually numerous ................... Peritaxia Horn

25′. Body with granulate papillae ............... ........................... Leptopinara O ’ Brien

26(23′). Elytra with long fine erect setae; elytral stria 10 extends posteriorly to above margin of posterior coxa, there becoming confluent with stria 9 .......... ........ Crocidema Van Dyke (including Amphidees macer Sharp and A. latifrons (Sharp))

26′. Elytra without erect setae; elytra stria 10 obscure, not joined to stria 9......27

27(26′). Rostrum on dorsal surface flat, with fine, longitudinal, glabrous median line; frons 2/5 wider than distance between lateral margins of rostrum at articulation of antenna in dorsal view; rostrum without deep, fine sulcus distad of eye......... ......................... Pseudorimus Van Dyke

27′. Rostrum on dorsal surface convex, with very vague, low, median, longitudinal carina; frons much less than 1/5 wider than distance between lateral margins of rostrum at articulation of antenna in dorsal view; rostrum at base slightly distad anterior margin of eye with short, deep, fine sulcus arranged perpendicularly to longitudinal axis of rostrum.............................. .................. Melanolemma Van Dyke