Dysmerus Casey

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

publication ID

http://doi.org/10.5281/zenodo.5405025

persistent identifier

http://treatment.plazi.org/id/87228798-FF89-6C53-6EDC-FA11FA6AFAB1

treatment provided by

Felipe

scientific name

Dysmerus Casey
status

 

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 View Figure 2-5 , 6); procoxal cavities closed ( Fig. 5 View Figure 2-5 ); intercoxal process of prothorax apically truncate ( Fig. 5 View Figure 2-5 ); intercoxal process of first visible abdominal segment narrow ( Fig. 5 View Figure 2-5 ); 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 View Figure 13-15 View Figure 16-18 , 21 View Figure 19-21 ) ............................................................... 2

— Head without median longitudinal carina .................................................................................... 5

2(1). Median longitudinal carina on head continues almost to anterior margin of epistome ( Fig. 18 View Figure 16-18 ) ( Peru) ................................................................................. D. skelleyi Thomas   , new species

— Median longitudinal carina on head does not continue to anterior margin of epistome ( Fig. 13-17 View Figure 13-15 View Figure 16-18 ) ................................................................................................................................................... 3

3(2). Head above antennal insertions produced, lobe-like ( Fig. 17 View Figure 16-18 , 21 View Figure 19-21 ); 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 View Figure 7-9 ) ..................................................................... 9

6(5). Pronotum shallowly but distinctly longitudinally sulcate; scape with long, curved dorsal extension ( Fig. 25 View Figure 22-27 ) ( 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 View Figure 2-5 , 8 View Figure 7-9 ) ( 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 View Figure 22-27 ); dorsal tubercle of scape located at anterior third ( Fig. 11 View Figure 10-12 ) ( Venezuela) .............................................................. D. genaspinosus Thomas   , new species

— Gena without spine next to eye; ventral process of scape simple ( Fig. 26 View Figure 22-27 ); dorsal tubercle of scape located at midpoint ( Fig. 15 View Figure 13-15 ) ( Argentina, Brazil) ....... D. monstrosus Thomas   , new species

9(5). Pronotum deeply longitudinally sulcate ( Fig. 19 View Figure 19-21 ) (Lesser Antilles) ..... D. sulcicollis Grouvelle  

— Pronotum not or weakly longitudinally sulcate ............................................. 10

10(9). Pronotum with secondary sublateral lines ( Fig. 21 View Figure 19-21 ); antennae very thick ( Fig. 20 View Figure 19-21 ) (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 View Figure 22-27 ) ( Bolivia) .................................................................................... D. boliviensis Thomas   , new species

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

— Clypeus acute anterolaterally, produced and reflexed ( Fig. 24 View Figure 22-27 ); scape apically acute ( Fig. 12 View Figure 10-12 ) ( 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 View Figure 19-21 ) ( Trinidad, Brazil) .............................................. D. trinidadensis Thomas   , new species

— Dorsal surface of scape with a strong tubercle at midpoint ( Fig. 17 View Figure 16-18 ); head above antennal insertions less produced ( Fig. 17 View Figure 16-18 ) ( Brazil) ................................ D. rondoniensis Thomas   , new species

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Laemophloeidae

Loc

Dysmerus Casey

Thomas, Michael C. 2009
2009
Loc

Brontophloeus

Kessel, F. 1921: 28
1921
Loc

Dasymerus

Grouvelle, A. 1908: 56
1908
Loc

Laemophloeus (Dysmerus)

Schwarz, E. A. 1889: 164
1889
Loc

Dysmerus

Casey, T. L. 1884: 97
1884