Hydrodessus jethoeae Makhan, 1994: 119

Miller, Kelly B., 2016, Revision of the Neotropical diving beetle genus Hydrodessus J. Balfour-Browne, 1953 (Coleoptera, Dytiscidae, Hydroporinae, Bidessini), ZooKeys 580, pp. 45-124 : 78-79

Taxon classification Animalia Coleoptera Dytiscidae

Hydrodessus jethoeae Makhan, 1994: 119 Figs 18, 42

Hydrodessus jethoeae Makhan, 1994: 119; Nilsson 2001: 236.

Type locality.

Surinam, District Brokopondo, Brownsweg.

Diagnosis.

Hydrodessus jethoeae is not particularly similar to any other species. Specimens are elongate and posteriorly attenuate (Fig. 18A). The dorsal surface is vaguely fasciate with variegations of yellow, brown and dark brown (Fig. 18A). The lateral elytral carina is elongate, extending about 1/2 length of the elytron (Fig. 18B). The prosternal process has distinctive lateral lobes anteriorly and is posteriorly abruptly narrowed (Fig. 18C). The metaventrite carinae are distinctive, extending across the metaventrite (Fig. 18C). They are slightly constricted anteriorly and moderately divergent posteriorly (Fig. 18C).

Description.

Measurements. TL = 2.9-3.0 mm, GW = 1.5 mm, PW = 1.4 mm, HW = 1.2-1.3 mm, EW = 0.9 mm, TL/GW = 2.0, HW/EW = 1.7. Body elongate, apically attenuated, very narrowly rounded, lateral margin discontinuous between pronotum and elytron (Fig. 18A).

Coloration (Fig. 18A). Head and pronotum yellow-orange. Elytra orange with diffuse pale areas anterolaterally, mediolaterally, subapically and in broad V-shape at apex, also with diffuse, dark brown areas laterally and around subapical pale region. Antennae, palpi and legs yellow. Venter yellow, dark on some sutures, especially basal abdominal sutures.

Sculpture and structure. Head broad, anterior clypeal margin broadly curved; surface shiny with many minute punctures; eyes large. Pronotum cordate, widest near anterior margin (Fig. 18A); lateral bead fine, somewhat obscured posteriorly; surface shiny, covered with fine punctures. Elytra elongate, apically strongly narrowed (Fig. 18A); lateral carina distinctive anteriorly, extending to about ½ length of elytron, but becoming lower and more rounded posteriorly (Fig. 18B); surface shiny, covered with fine punctures. Prosternum medially rounded and setose; prosternal process relatively slender, widest at anterior laterally expanded lobes, posteriorly abruptly narrowed, then margins subparallel to rounded apex, lateral margins strongly carinate, longitudinally strongly excavated (Fig. 18C). Metaventrite with anterior process slender, anteriorly rounded, longitudinally somewhat excavated (Fig. 18C); metasternal carinae closely approximated anteriorly, divergent but not broadly, posteriorly extending to posterior margin of metaventrite near anterior ends of metacoxal lines (Fig. 18C); surface covered with fine punctation. Legs with surfaces covered with fine punctation; pro- and mesotibiae moderately broad; metatrochanter strongly offset and apically rounded; metatibia with posteroapical brush of setae; metacoxa covered with fine punctation; metacoxal lines approximated, parallel (Fig. 18C). Abdominal ventrites covered with fine punctation; VI apically broadly rounded.

Male genitalia. Median lobe of type broken, lateral lobes absent. Median lobe in lateral aspect slender, curved basally, slightly curved through apical portion, apex slender and slightly recurved and deflexed, apically finely rounded (Fig. 18D); in ventral aspect slender, lateral margins slightly convergent, apex rounded (Fig. 18E).

Female genitalia. Not examined.

Sexual dimorphism. None examined.

Variation. Among the three specimens examined there is some minor variation in extent and pattern of coloration on the elytron.

Distribution.

In addition to the type locality in Brokopondo District, Suriname, this species is known from two sites, one in Bolivar State, Venezuela and another in Sipaliwini District, Suriname (Fig. 42).

Habitat.

Hydrodessus jethoeae has been collected from a river margin and at a UV light.

Discussion.

The type specimen had been dissected for examination in this study, and the base of the male median lobe and the lateral lobes were damaged and could not be illustrated. Other than the male type specimen, only two female specimens are known for this species, they are very similar to each other and distinct from all other species. They were also collected quite some distance from each other. Despite the lack of knowledge of males, it seems likely that future association of specimens with this species will not be problematic.

Specimens.

Holotype: ♂ in RMNH labeled, "Suriname District Brokopondo Brownsweg 7.8.1984 leg. D.Makhan/ Hydrodessus jethoeae det. D. Makhan 1994 / Holotype [red label]."

Suriname; Sipaliwini District, Camp 1, on Juari River, 2.175°N, 56.788°W, 19 Aug 2010, uv light, Short and Miller (1 female, KUNHM, SEMC0915510). Venezuela; Bolivar State Rio, Caripito, nr. Rio Orinoco, river margin, 6.58694°N; 67.02912°W 12.i.2009, Short & Miller VZ09-0112-02A/ [barcode label] (1 female, KUNHM, SEMC0854749).