Heterocerus tenuis Miller 1988b: 30 The variegated mud-loving beetles (Coleoptera: Heteroceridae) of Mississippi and Alabama, with discussion and keys to the species occurring in the southeastern United States King, Jonas G. Lago, Paul K. Insecta Mundi 2012 2012-12-28 2012 275 1 53 Miller Miller 1988 [237,584,1698,1722] Insecta Heteroceridae Heterocerus Animalia Coleoptera 28 27 Arthropoda species tenuis  ( Fig. 22, 49, 69)      Heterocerus tenuis Miller 1988b: 30.   Description.Length 3.0 - 3.5 mm. General appearance ( Fig. 22) and male genitalia ( Fig. 49) very similar to those of  H. schwarzi; however, dorsal spine-like projections on either side of the anterior edge of the median plate point outward in the ventral view of the male genitalia.   Diagnosis.  Heterocerus tenuisis nearly identical to  H. schwarziand can be separated from this species only through differences in the male genitalia. The dorsal spine-like projections on either side of the anterior edge of the median plate in  H. tenuisproject laterally in the ventral view ( Fig. 49), a character not present in any other member of the undatus group. These two species are not known to be sympatric, but it should be noted that their known ranges are patchy.  Notes.Because  H. tenuisand  H. schwarziare nearly identical, the possibility that the two species were synonymous was considered. A comparison of six paratypesof  H. schwarziand 23 paratypesof  H. tenuiswas made and none exhibited genital characters that could be considered intermediate. The two species appear to be valid.   Distribution.This species is known from Florida, southern Georgiaand Rondeau Park, Ontario ( Fig. 69). Rondeau Provincial Park is located on a peninsula on the north shore of Lake Erie. The wide gap in the range, and ecology, between the two regions populated by this species, along with Rondeau Parks proximity to some of the major shipping hubs of the St. Lawrence Seaway system, suggests that interstate commerce could have established  H. tenuisin this isolated northern locale.  Specimens examined.16 (See Appendix).