Heterocerus intermuralis (Pacheco)

King, Jonas G. & Lago, Paul K., 2012, The variegated mud-loving beetles (Coleoptera: Heteroceridae) of Mississippi and Alabama, with discussion and keys to the species occurring in the southeastern United States, Insecta Mundi 2012 (275), pp. 1-53 : 20-21

7. Heterocerus intermuralis (Pacheco)

New Combination

( Fig. 12 , 34 , 60 )

Neoheterocerus intermuralis Pacheco 1964: 91 .

Description. Length 3.9 - 5.9 mm. Elytra grayish-brown, without reddish hue; dominated by pale markings that are highly variable in shape and definition and only vaguely trifasciate ( Fig. 12 ); striae absent. Pronotal disc usually darker than elytra, apical angles of the pronotum pale or lateral pronotal margins evenly pale. Post-metathoracic coxal and post-mesothoracic coxal lines absent. Male genitalia ( Fig. 34 ) of the typical Heterocerus type; anterior one-third of phallobase constricted to half of its greatest width, dorsal plate strongly notched on anterior and posterior edges (as in Fig. 38 ); parameres triangular, with medial edges diverging slightly. Hypermandibulate males common.

Diagnosis. This species is easily separated from similar H. pallidus and H. gnatho due to its grayishbrown elytral hue. The elytra of the other two species range from testaceous to dark brown. If there is a question of identity, the male genitalia should be examined. The anterior third of the phallobase is constricted to a far greater extent than any other North American Heterocerus that lack post-mesothoracic coxal lines.

Notes. During this study, specimens of H. intermuralis were collected from a variety of riparian habitats in Mississippi, as well as from widely separated spring fed mud-banked ponds and lakes in west Texas. Specimens were collected by Testa and Lago near brackish ponds on Point Clear Island, Hancock County, Mississippi, but this species was not reported as such by Lago et al. (2002).

Distribution. Heterocerus intermuralis was previously recorded only from southern Texas. As part of this study, it was collected from three lacustrain locations in west Texas and eight in Mississippi ( Fig. 60 ). Six Mississippi collection sites are located along rivers on the Mississippi Alluvial Plain, and another on the Pascagoula River, 2 miles from the Mississippi sound. Two specimens were collected on Point Clear Island, Hancock County, Mississippi, by Testa and Lago (reported as H. fatuus in Lago et al. 2002). Several series from the Dominican Republic were discovered among specimens in the Carnegie Museum, which marks the first Caribbean record for H. intermuralis .

Specimens examined. 171 (See Appendix).

Figures

Figures 11-17. Habiti of large Heterocerus species lacking post-mesocoxal lines. 11) H. pallidus (male is hypermandibulate). 12) H.intermuralis (male is hypermandibulate). 13) H.fatuus. 14) H. gnatho. 15) H.longilobulus. 16) H. sandersoni. 17) H. angustatus.Scale line = 1mm.

Figures 32-44. Male genitalia of southeastern Heterocerus species. The ventral view is shown unless otherwise stated. 32-39) Species that lack post-mesocoxal lines. 32) H. fatuus. 33) H. glicki. 34) H. intermuralis. 35) H. angustatus; left - ventral view, right - dorsal view. 36) H. longilobulus. 37) H. pallidus; left - ventral view, right - dorsal view. 38) H. gnatho; left - ventral view, right - dorsal view. 39) H. sandersoni; left - ventral view, center - dorsal view, left - lateral view. 40-44) Species with post-mesocoxal lines. 40) H. sinuosus; left - dorsal view, right - ventral aspect. 41) H. mollinus. 42) H. insolens; left - dorsal view, right - ventral aspect. 43) H. parrotus. 44) H. brunneus.

Figures 58-65. Distribution by county in the United States. 58) Heterocerus fatuus. 59) Heterocerus sandersoni. 60) Heterocerus intermuralis. 61) Heterocerus angustatus. 62) Heterocerus mollinus. 63) Heterocerus selanderi.64) Distribution of Heterocerus sinuosis by county in Mississippi. 65) Distribution of Heterocerus collaris by county in the United States.