Hydrodessus kylei, 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 : 83-86

Taxon classification Animalia Coleoptera Dytiscidae

Hydrodessus kylei sp. n. Figs 21, 38, 43

Type locality.

Venezuela, Amazonas, Cerro de la Neblina, basecamp, 0.833°N, 66.167°W.

Diagnosis.

Hydrodessus kylei is the only known Hydrodessus species with distinctly emarginate eyes (best seen in dorsal aspect) (Fig. 21A). This is a red species with the head and pronotum often somewhat lighter red and with moderately poorly-defined pale maculae on the elytra (Fig. 21A). There is one macula subapically that is triangular and a narrow lighter region apically (Fig. 21A). The carinae on the metaventrite are broadly divergent posteriorly with a prominent constriction immediately posterad of the metaventral process (Fig. 21C). This species is sexually dimorphic in body shape with the male apically broadly pointed (Fig. 21A1) and the female apically subtruncate to very broadly pointed (Fig. 21A2). The species is most similar to Hydrodessus kurti which has a similar sexual dimorphism but does not have emarginate eyes. The male genitalia are also different. 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 (Fig. 21E). In lateral aspect the median lobe is similarly broadly curved but apically somewhat more robust (Fig. 21D). The lateral lobe is considerably broader in Hydrodessus kylei (Fig. 21F) than in Hydrodessus kurta (Fig. 20F).

Description.

Measurements. TL = 2.7-2.8 mm, GW = 1.3 mm, PW = 0.9-1.1 mm, HW = 0.7 mm, EW = 0.3-0.5 mm, TL/GW = 2.1-2.2, HW/EW = 2.0-2.2. Body robust, broad, apically pointed, lateral outline slightly discontinuous between pronotum and elytron (Fig. 21A).

Coloration (Fig. 21A). Head dark red. Pronotum dark red, yellow-red anteriorly. Elytra dark red with diffuse, yellow-red macula subapically and with apex yellow-red (Fig. 21A). Antennae, palps and legs brown. Venter dark red-brown, lighter on elytral epipleuron and abdominal ventrites V-VI.

Sculpture and structure. Head broad, anterior margin broadly rounded; surface covered with microreticulation and very fine punctures; eyes large, laterally with distinctive concavity. Pronotum slightly cordate, widest near middle (Fig. 21A); surface shiny with fine microreticulation and irregular punctation with some larger and smaller. Elytra elongate, apex pointed; lateral carina distinctive, but short, only present near humeral angle (Fig. 21B); surface shiny with fine microreticulation and fine punctures. Prosternum medially carinate with long, fine setae; prosternal process moderately broad, widest at anterior lateral lobes, lateral carinae convergent posteriorly to rounded apex, medially longitudinally excavated (Fig. 21C). Metaventrite with anterior process moderately narrow, anteriorly truncate, constricted subapically, medially somewhat excavated; metasternal carinae distinctive, broadly divergent posteriorly, ending near anterior ends of metacoxal lines (Fig. 21C); surfaces covered with dense, fine punctation. Surfaces covered with fine punctation; pro- and mesotibiae not broad; metatibia with posteroapical brush of setae; metatrochanter only slightly offset, apically narrowly rounded. Metacoxa covered with dense, fine punctation; metacoxal lines prominent, broadly separate, distictly divergent anteriorly (Fig. 21C). Abdominal ventrites covered with dense, fine punctation; ventrite VI apically evenly rounded.

Male genitalia. Median lobe bilaterally asymmetrical, in lateral aspect very strongly curved, with base extremely large and triangular, apical portion strongly curved, dorsal margin somewhat expanded, apex slightly sinuate and narrowly rounded (Fig. 21D); in ventral aspect broad basally, basal half with lateral margins subparallel, left margin straight to near apex, right margin strongly constricted submedially, margin divergent medially, apex broadly expanded and strongly obliquely truncate (Fig. 21E). Lateral lobe extremely broad, ventral margin very strongly curved, dorsal margin concave, apex a narrowly rounded lobe directed posteriorly (Fig. 21F).

Female genitalia. Gonocoxosternite transversely broad, apex broadly angulate, anterior portion moderately large, subtriangular, anterior apex rounded (Fig. 38). Gonocoxa slender, apical portion slender and apically narrowly rounded, anterior apodeme longer than apical portion, slender (Fig. 38). Bursa extremely large, elongate and broad; spermathecal duct extremely long and slender, expanded near receptacle which is semispherical; spermatheca elongate and slender, with distinctive spermathecal spine; fertilization duct extremely long, slender, and coiled (Fig. 38).

Sexual dimorphism. Male pro- and mesotarsi I–III more broadly expanded than female and ventrally with several large adhesive setae. The female elytral apex is more broadly rounded, and subapically slightly lobed on each side than in male.

Variation. The subapical and apical pale areas are variably distinctive between specimens.

Etymology.

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

Distribution.

This species is found in Amazonas, Venezuela and in southern Suriname (Fig. 43).

Habitat.

Specimens have been collected along the margins of a forest river, from a large, sandy creek, and at UV light.

Specimens.

The male holotype is in MIZA labeled, "VENEZUELA,T.F.Amaz. Cerro de la Neblina Basecamp. 140 m. 0°50'N, 66°10'W 28 January 1985/ Netted along margins of Rio Baria P.J. & P.M.Spangler, R.Faitoute.W. Steiner/ HOLOTYPE Hydrodessus kylei Miller, 2016 [red line with black line border]."

Paratypes, 83 total. Suriname, Sipaliwini District, Camp 1, Upper Palumeu, 2.477°N, 55.629°W, 14 Mar 2012, large sandy creek, 275m, A. Short (18, KUNHM, museum numbers in Table 1); same except, Camp 1 on Kutari River, 2.175°N, 56.787°W, 19 Aug 2010, UV light, 275m, A. Short (1, KUNHM, SEMC0915690). Venezuela, Amazonas, Cerro de la Neblina Basecamp, 0.833°N, 66.167°W, 20 Feb 1985, Netted along margins of Rio Baria, 140m, P.J. Spangler, P.M.Spangler, R. Faitoute, W. Steiner (50, MIZA, USNM, MSBA, KUNHM); same except 27 Jan 1985 (1, USNM); same except 28 Jan 1985 (13, MIZA, USNM, MSBA, KUNHM).