Dysmerus Casey 1884: 97
Laemophloeus ( Dysmerus ), Schwarz 1889: 164
Dasymerus Grouvelle 1908: 56
Brontophloeus Kessel 1921: 28
A review of the genus Dysmerus Casey (Coleoptera: Laemophloeidae)
Thomas, Michael C.
Insecta Mundi
2009
2009-05-08
2009
74
1
30
495P
1619734
Casey
Casey
1884
[301,520,1507,1531]
Insecta
Laemophloeidae
Dysmerus
Animalia
Coleoptera
3
2
Arthropoda
genus
Dysmerus Casey 1884: 97 Laemophloeus( Dysmerus), Schwarz 1889: 164 Dasymerus Grouvelle 1908: 56, misspelling Brontophloeus Kessel 1921: 28
Typespecies. Dysmerus basalis Casey 1884: 97, by monotypy. BrontophloeusKessel, Dysmerus basalisCasey, by subsequent designation by Lefkovitch (1958: 97); synonymy by Lefkovitch (1958: 97).
Diagnosis.The combination of the following character states is diagnostic for the members of this genus: body elongate, parallel-sided and somewhat subcylindrical; pedicel attached laterally to scape, which is highly modified in males ( Fig. 2-4, 6); procoxal cavities closed ( Fig. 5); intercoxal process of prothorax apically truncate ( Fig. 5); intercoxal process of first visible abdominal segment narrow ( Fig. 5); tarsal formula 5-5- 4 inmales, 5-5- 5 infemales. Species of Dysmerusare uniformly testaceous in color, have sublateral pronotal lines composed of a groove bordered laterally by a ridge, and all three elytral cells are complete.Sublateral lines of the pronotum and head are distinguishing features of all laemophloeids ( Thomas 2002); elytral cells were defined and first used by Lefkovitch (1962).
Distribution.Members of the genus Dysmerus are restricted to the New World, where they range from the southeastern United Statessouth to Bo- livia and Argentina. The genus seems have a lim- ited distribution in the West Indies: D. basalisin the Bahamas, D. sulcicollison Montserratand Guadeloupe, and D. caseyion Grenada. I have seen no Dysmerusspecimens from the Greater Antilles or any other of the Lesser Antilles.
Discussion. Dysmerusbelongs to an informal group of genera including CryptolestesGanglbauerand LeptophloeusCasey. Allthree genera share a similar body plan and structure of the male genitalia. Dysmerusand Leptophloeusare subcylindrical in body form and have a narrow abdominal intercoxal process. However, no known Leptophloeuspossesses a modified male antennal scape. Females of some Leptophloeusspecieshave a sclerotized bursa copulatrix ( Karner 1997), as do many Cryptolestes, which is absent in Dysmerusfemales. Species of Cryptolestesare more dorsoventrally compressed and have a broader abdominal intercoxal process. Many species of Cryptolestespossess a modified male antennal scape ( Lefkovitch 1958, Thomas 1988). All Dysmerusspecieshave antennal insertions situated in an excavation on the frons, and the side of the head is deeply excavated anterior to the eyes, which apparently provides freedom of movement for the enlarged scape. Figure 1. Dysmerus basalisCasey, male, dorsal habitus. Based on morphological characters, there are several apparent groups of species within Dysmerus. Four species ( D. caseyi, D. politus, D. impolitus, and D. symphilus) share a particular habitus, possessing a slightly fusiform body shape, and rather simple scape structure and have inconspicuous pubescence. All other species have conspicuous dorsal pubescence and more complex scape. Dysmerus basalisand D. mexicanusare very similar in head and scape structure and seem to be closely related. Major males are easily identified by their scape structure. In most cases minor males, with less developed scapes, are still identifiable through a combination of other characters. Females of the species near D. caseyishould readily key out; females of other species are more problematic but can generally be identified through associated males and based on distribution. In the following new species treatments, all designated paratypesare males, except for D. impolitus, D. politus, and D. symphilus.In some cases, the median longitudinal line on the head vin species where that line is not carinate may appear carinate due to light reflection off the shiny surface. Viewing the specimen at an oblique angle under diffused light will reveal the actual nature of the longitudinal line.
Key to Males of DysmerusCasey 1. Head with median longitudinal carina ( Fig. 13-18, 21) ............................................................... 2 — Head without median longitudinal carina .................................................................................... 5 2(1). Median longitudinal carina on head continues almost to anterior margin of epistome ( Fig. 18) ( Peru) ................................................................................. D. skelleyiThomas, new species — Median longitudinal carina on head does not continue to anterior margin of epistome ( Fig. 13-17) ................................................................................................................................................... 3 3(2). Head above antennal insertions produced, lobe-like ( Fig. 17, 21); pronotum shallowly, longitudinally sulcate; body conspicuously pubescent ..................................................................................... 14 — Head above antennal insertions not produced and lobe-like; body not conspicuously pubescent 4 4. Dorsal integument glossy, not microreticulate ( Bolivia, Brazil) .................................................... ............................................................................................ D. politusThomas, new species — Dorsal integument dull, strongly microreticulate ( Brazil) ............................................................ ........................................................................................ D. impolitusThomas, new species 5(1). Eyes small, pyramidal in shape (Fig. 7,14) ................................................................................. 6 — Eyes larger, not pyramidal in shape (e. g., Fig. 9) ..................................................................... 9 6(5). Pronotum shallowly but distinctly longitudinally sulcate; scape with long, curved dorsal extension ( Fig. 25) ( Mexico) ......................................................... D. mexicanusThomas, new species — Pronotum not sulcate; scape without long, curved dorsal extension ........................................... 7 7(6). Scape with ventral extension ........................................................................................................ 8 — Scape without ventral extension ( Fig. 2-4, 8) ( USA, Bahamas) ...................... D. basalisCasey 8(7). Gena with laterally directed spine present next to anteroventral corner of eye (Fig. 43); ventral process of scape bifurcate ( Fig. 23); dorsal tubercle of scape located at anterior third ( Fig. 11) ( Venezuela) .............................................................. D. genaspinosusThomas, new species — Gena without spine next to eye; ventral process of scape simple ( Fig. 26); dorsal tubercle of scape located at midpoint ( Fig. 15) ( Argentina, Brazil) ....... D. monstrosusThomas, new species 9(5). Pronotum deeply longitudinally sulcate ( Fig. 19) (Lesser Antilles) ..... D. sulcicollisGrouvelle — Pronotum not or weakly longitudinally sulcate ............................................. 10 10(9). Pronotum with secondary sublateral lines ( Fig. 21); antennae very thick ( Fig. 20) (Central and South America) ............ D. symphilusThomas, new species — Pronotum without secondary sublateral lines; antennae normal ................... 11 11(10). Body not conspicuously pubescent (Central and South America, Lesser Antilles). ..................... D. caseyi(Grouvelle) — Body conspicuously pubescent ........... 12 12(11). Antennal scape curved, more or less sickle-
shaped ............................................. 13 Figure 6. Dysmerus basalisCasey, female, dorsal view of head. Figure 7-9.Head and pronotum of males of Dysmerus: 7) D. basalisCasey; 8) D. boliviensisThomas, n. sp.; 9) D. caseyi(Grouvelle). — Antennal scape complex, emarginate anteriorly, with blunt ventral projections ( Fig. 22) ( Bolivia) .................................................................................... D. boliviensisThomas, new species
13(12). Clypeus acute anterolaterally, but not reflexed; scape apically blunt ( Fig. 10) ( Argentina, Brazil) .................................................................................... D. curvicornisThomas, new species — Clypeus acute anterolaterally, produced and reflexed ( Fig. 24); scape apically acute ( Fig. 12) ( USA, Mexico, Costa Rica) ...................................... D. hamaticornisThomas, new species 14(3). Dorsal surface of scape without a tubercle; head above antennal insertions more produced ( Fig. 21) ( Trinidad, Brazil) .............................................. D. trinidadensisThomas, new species — Dorsal surface of scape with a strong tubercle at midpoint ( Fig. 17); head above antennal insertions less produced ( Fig. 17) ( Brazil) ................................ D. rondoniensisThomas, new species