Hydrodessus kurti, Miller, Kelly B., 2016

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 : 82-83

Taxon classification Animalia Coleoptera Dytiscidae

Hydrodessus kurti sp. n. Figs 20, 47

Type locality.

Suriname, Sipaliwini District, Camp 1, Upper Palumeu, 2.477°N, 55.629°W.

Diagnosis.

This is a red species with the head and pronotum often somewhat lighter red and with moderately well-defined pale maculae on the elytra (Fig. 20A). There is one macula subapically that is triangular and a narrow macula at the apex (Fig. 20A). The carinae on the metaventrite are broadly divergent posteriorly with a prominent constriction immediately posterad of the metaventral process (Fig. 20C). This species is sexually dimorphic in body shape with the male apically broadly pointed (Fig. 20A1) and the female apically subtruncate to very broadly pointed (Fig. 20A2). The species is most similar to Hydrodessus kylei which has a similar sexual dimorphism. That species has the eyes conspicuously emarginate (best seen in dorsal aspect). The male genitalia are different, as well. The median lobe in Hydrodessus kurti is bilaterally symmetrical with the apex rounded in ventral aspect (Fig. 20E). In lateral aspect the median lobe is broadly curved with the apex very slender, sinuate and very sharply pointed (Fig. 20D). The median lobe in Hydrodessus kylei is bilaterally asymmetrical with the apex obliquely truncate in ventral aspect. In lateral aspect the median lobe is similarly broadly curved but apically somewhat more robust (Fig. 21D). The lateral lobe is considerably narrower in Hydrodessus kurti (Fig. 20F) than in Hydrodessus kylie (Fig. 21F).

Description.

Measurements. TL = 2.6-2.7 mm, GW = 1.3 mm, PW = 1.0 mm, HW = 0.7-0.8 mm, EW = 0.5 mm, TL/GW = 2.0-2.1, HW/EW = 1.5-1.6. Body moderately robust, apically pointed, lateral outline distinctly discontinous between pronotum and elytron (Fig. 20A).

Coloration (Fig. 20A). Head red. Pronotum red to orange-red laterally, medially and along anterior margin with large, diffuse dark red area. Elytra red with subapical pale macula, apex pale (Fig. 20A). Antennae and palps yellow-orange to yellow. Legs yellow-orange to yellow, metacoxa dark red. Venter dark red on most surfaces, lighter orange on, prothorax, elytral epipleuron and apex of abdomen.

Sculpture and structure. Head moderately broad, anterior clypeal margins broadly rounded; surface shiny, microreticulate with few sparse punctures; eyes large. Pronotum slightly cordate, widest near anterior margin (Fig. 20A); lateral bead very fine and distinct throughout length; surface shiny, covered with fine punctures. Elytra elongate, apically pointed (Fig. 20A); lateral carina distinctive but short, about 1/5 length of elytron (Fig. 20B); surface shiny with punctures fine over entire surface, with one moderately impressed longitudinal line medially on disc. Prosternum medially somewhat swollen, rounded; prosternal process moderately broad, widest at anterior angles, narrowed posteriorly with posterior portion with lateral carinate margins subparallel, medially longitudinally excavated, apex truncate (Fig. 20C). Metaventrite with anterior process moderately broad, apex rounded, medially slightly impressed with lateral margins broadly beaded; metasternal carinae distinctive across metasternum, though rounded and less distinctive posteriorly, slightly curved and distinctly divergent posteriorly, posterior terminus distinctly mediad of anterior ends of metacoxal lines (Fig. 20C); metaventrite covered with fine punctation. Legs shiny, most surfaces with very fine, indistinct punctures; metatibia with posteroapical brush of setae distinctive; pro- and mesotibiae broad; metatrochanter somewhat offset, apically narrowly rounded; metacoxa covered with fine punctures; metacoxal lines distinctive, broadly divergent anteriorly (Fig. 20C). Abdomen covered with fine punctures; VI apically laterally somewhat compressed with medially apex pointed.

Male genitalia. Median lobe bilaterally symmetrical, in lateral aspect moderately broad basally, medially strongly curved, slender, apically slender and apex slightly but distinctly sinuate, very slender and sharply pointed (Fig. 20D); in ventral aspect narrow basally, lateral margins slightly divergent apically to broadly rounded apex (Fig. 20E). Lateral lobe broad basally, apically broadly curved, apex straightened, broad, and apically broadly rounded, with distinct cluster of setae apically and along dorsal margin (Fig. 20F).

Female genitalia. Not examined.

Sexual dimorphism. Male pro- and mesotarsi I–III more broadly expanded than female and ventrally with several large adhesive setae. Females with posterolateral margins of elytra expanded laterally and broadly lobate (Fig. 20A2), males with elytral margins not lobed (Fig. 20A1). Female abdominal ventrite VI not as laterally compressed as in male, and less strongly pointed medially.

Variation. Specimens vary somewhat in depth of coloration. In particular, the medial darkened region of the pronotum is variable with some specimens having that area smaller and others larger.

Etymology.

This species is named kurti in honor of the author’s brother, Kurt B. Miller.

Distribution.

Hydrodessus kurti is known only from the type locality in southern Suriname (Fig. 47).

Habitat.

The type series was collected from a large, sandy creek.

Specimens.

The holotype male is in NZCS labeled, "SURINAME: Sipaliwini District N 2.47700°, W 55.62941°,275 m Camp 1, Upper Palumeu leg.A.Short; large sandy creek 14.iii.2012; SR12-0314-01A 2012 CI-RAP Survey/ SEMC1088337 KUNHM-ENT/ Hydrodessus kurti Miller, 2016 [red line with black line border]."

Paratypes, 6 total. Suriname, Sipaliwini District, Camp 1, Upper Palumeu, 2.477°N, 55.629°W, large sandy creek, 275m, A. Short (6, KUNHM, SEMC1088338, SEMC1088339, SEMC1088342, SEMC1088346, SEMC1088347, SEMC1088351).