Hydrodessus peloteretes Spangler, 1985

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 : 98-100

Taxon classification Animalia Coleoptera Dytiscidae

Hydrodessus peloteretes Spangler, 1985 Figs 28, 42

Hydrodessus peloteretes Spangler, 1985: 80; Biström 1988: 37; Nilsson 2001: 236.

Type locality.

Guyana, Mazaruni-Potaro District, Takutu Mountains, 6°15'N, 59°5'W.

Diagnosis.

This species is largely red dorsally (Fig. 28A). The pronotum is yellow and the elytral apex is yellow as is a poorly-defined macula at about 2/3 length of elytron (Fig. 28A). The pronotum is not as broadly curved as most species, and is broadest near the posterior angles with its greatest width distinctly less than the greatest width across the elytra (Fig. 28A). The prosternal process is relatively narrow with distinctive lateral lobes anteriorly (Fig. 28C). The metaventrite carinae are strongly divergent posteriorly and each carina is expanded near the posterior apex (Fig. 28C). The male median lobe is broadly triangular basally, sharply curved near base of apical portion, and apically sinuate (Fig. 28D). In ventral aspect the median lobe is bilaterally symmetrical with the lateral margins subparallel and the apex rounded (Fig. 28E). The lateral lobe is very broad with the apex narrowly lobate (Fig. 28F).

Description.

Measurements. TL = 2.7 mm, GW = 1.3 mm, PW = 1.0 mm, HW = 0.7 mm, EW = 0.5 mm, TL/GW = 2.2, HW/EW = 1.6. Body shape elongate, lateral margin evenly concavely curved between pronotum and elytron, apically pointed (Fig. 28A).

Coloration (Fig. 28A). Head yellow-brown. Pronotum yellow. Elytron yellow brown with vague pale macula subapically and apex yellow. Antennae, palps and legs yellow. Venter yellow to yellow-brown, darker brown on Metaventrite and other thoracic ventrites.

Sculpture and structure. Head broad, anterior clypeal margin evenly curved; surface shiny, covered with minute punctures; eyes moderately small. Pronotum with lateral margins more strongly curved anteriorly, but pronotum widest at posterolateral angles; lateral bead very fine, but continuous; surface shiny, covered with minute punctures. Elytra elongate, apically pointed (Fig. 28A); lateral carina indistinct, rounded, evident only at humeral angle (Fig. 28B); surface covered with minute, dense punctation. Prosternum medially tectiform and setose; prosternal process broadest at anterior, laterally expanded lobes, lateral margins concave, distinctly convergent to rounded apex, longitudinally excavated (Fig. 28C). Metaventrite with anterior process moderately slender, apex narrowly truncate, distinctly expanded subapically with prominent lateral lobes, medially somewhat impressed; metasternal carina distinct anteriorly, closely approximated, posteriorly obsolete, represented by strongly diverging lines of impunctate surface (Fig. 28C); other surfaces covered with fine punctation. Legs with most surfaces covered with fine, irregular punctation; metatibia with distinctive brush of dense, elongate setae on postero-apical surface; pro- and mesotibiae moderately slender; metatrochanter somewhat offset, apically broadly pointed; metacoxa evenly covered with fine punctures; metacoxal lines broadly separated, broadly divergent anteriorly (Fig. 28C). Abdomen shiny, evenly covered with fine punctures, apically somewhat rugulose; apex of VI rounded.

Male genitalia. Median lobe bilaterally symmetrical, in laterl aspect very broadly curved, broad basally, strongly constricted medially, more expanded, but slender in apical half, sinuate with apex slender and pointed (Fig. 28D); in ventral aspect nearly parallel-sided, moderately broad with apex broadly rounded (Fig. 28E). Lateral lobe very broad, terminating in small, slender, slightly curved lobe, with two patches of setae, apically on lobe, and subapically along ventral margin (Fig. 28F).

Female genitalia. Not examined.

Sexual dimorphism. Only the male holotype examined.

Variation. Only the male holotype examined.

Distribution.

This species is known only from the Takutu Mountains of northern Guyana (Fig. 42).

Habitat.

The single known specimen was collected from a blacklight in a forest clearing near some streams.

Specimens.

The holotype male in USNM was examined, it is labeled, "GUYANA: Mazaruni- Potaro District Takutu Mountains 6°15'N, 59°5'W 17 December 1983/ EARTHWATCH Research Expedition: P. J. Spangler & W. E. Steiner Collectors/ At blacklight in forest clearing near streams/ HOLOTYPE Hydrodessus peloteretes PJ Spangler [red label]/ BLNO 003804 [blue label with black line around margin]."