Dysmerus Casey, 1884

Thomas, Michael C., 2009, A review of the genus Dysmerus Casey (Coleoptera: Laemophloeidae), Insecta Mundi 2009 (74), pp. 1-30 : 2-6

GENUS Dysmerus Casey

Dysmerus Casey 1884: 97

Laemophloeus (Dysmerus), Schwarz 1889: 164

Dasymerus Grouvelle 1908: 56 , misspelling

Brontophloeus Kessel 1921: 28

Type species. Dysmerus basalis Casey 1884: 97 , by monotypy. Brontophloeus Kessel , Dysmerus basalis Casey , 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 in males, 5-5- 5 in females.

Species of Dysmerus are 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 States south to Bo-

livia and Argentina. The genus seems have a lim-

ited distribution in the West Indies: D. basalis in

the Bahamas, D. sulcicollis on Montserrat and

Guadeloupe, and D. caseyi on Grenada. I have seen

no Dysmerus specimens from the Greater Antilles

or any other of the Lesser Antilles.

Discussion. Dysmerus belongs to an informal group of genera including Cryptolestes Ganglbauer and Leptophloeus Casey. All three genera share a similar body plan and structure of the male genitalia. Dysmerus and Leptophloeus are subcylindrical in body form and have a narrow abdominal intercoxal process. However, no known Leptophloeus possesses a modified male antennal scape. Females of some Leptophloeus species have a sclerotized bursa copulatrix ( Karner 1997), as do many Cryptolestes , which is absent in Dysmerus females. Species of Cryptolestes are more dorsoventrally compressed and have a broader abdominal intercoxal process. Many species of Cryptolestes possess a modified male antennal scape ( Lefkovitch 1958, Thomas 1988). All Dysmerus species have 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 basalis Casey , 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 basalis and D. mexicanus are 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. caseyi should 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 paratypes are 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 Dysmerus Casey

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. skelleyi Thomas , 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. politus Thomas , new species

— Dorsal integument dull, strongly microreticulate ( Brazil) ............................................................ ........................................................................................ D. impolitus Thomas , 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. mexicanus Thomas , 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. basalis Casey

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. genaspinosus Thomas , 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. monstrosus Thomas , new species

9(5). Pronotum deeply longitudinally sulcate ( Fig. 19 ) (Lesser Antilles) ..... D. sulcicollis Grouvelle

— 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. symphilus Thomas , 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 basalis Casey , female, dorsal view of head.

— Antennal scape complex, emarginate anteriorly, with blunt ventral projections ( Fig. 22 ) ( Bolivia) .................................................................................... D. boliviensis Thomas , new species

13(12). Clypeus acute anterolaterally, but not reflexed; scape apically blunt ( Fig. 10 ) ( Argentina, Brazil) .................................................................................... D. curvicornis Thomas , new species

— Clypeus acute anterolaterally, produced and reflexed ( Fig. 24 ); scape apically acute ( Fig. 12 ) ( USA, Mexico, Costa Rica) ...................................... D. hamaticornis Thomas , new species

14(3). Dorsal surface of scape without a tubercle; head above antennal insertions more produced ( Fig. 21 ) ( Trinidad, Brazil) .............................................. D. trinidadensis Thomas , new species

— Dorsal surface of scape with a strong tubercle at midpoint ( Fig. 17 ); head above antennal insertions less produced ( Fig. 17 ) ( Brazil) ................................ D. rondoniensis Thomas , new species

Figures

Figure 2-5. Dysmerus basalis Casey, male: 2) Head, dorsal view; 3) Head, lateral oblique view; 4) Head, frontal oblique view; 5) Ventral view, head, pro-, meso-, and metathorax.

Figure 13-15. Head and pronotum of males of Dysmerus: 13) D. impolitus Thomas, n. sp.; 14) D. mexicanus Thomas, n. sp.; 15) D. monstrosus Thomas, n. sp.

Figure 16-18. Head and pronotum of males of Dysmerus: 16) D. politus Thomas, n. sp.; 17) D. rondoniensis Thomas, n. sp.; 18) D. skelleyi Thomas, n. sp.

Figure 19-21. Head and pronotum of males of Dysmerus: 19) D. sulcicollis Grouvelle; 20) D. symphilus Thomas, n. sp.; 21) D. trinidadensis Thomas, n. sp.

Figure 7-9. Head and pronotum of males of Dysmerus: 7) D. basalis Casey; 8) D. boliviensis Thomas, n. sp.; 9) D. caseyi (Grouvelle).

Figure 22-27. Oblique view of head and antennal scape of males of Dysmerus: 22) D. boliviensis Thomas, n. sp.; 23) D. genaspinosus Thomas, n. sp.; 24) D. hamaticornis Thomas, n. sp.; 25) D. mexicanus Thomas, n. sp.; 26) D. monstrosus Thomas, n. sp.; 27) D. rondoniensis Thomas, n. sp.

Figure 10-12. Head and pronotum of males of Dysmerus: 10) D. curvicornis Thomas, n. sp.; 11) D. genaspinsosus Thomas, n. sp.; 12) D. hamaticornis Thomas, n. sp.