Fontidessus aquarupe Miller & Montano

Miller, Kelly B. & Montano, Elizabeth T., 2014, Review of the genus Fontidessus Miller & Spangler, 2008 (Coleoptera, Dytiscidae, Hydroporinae, Bidessini) with description of four new species, ZooKeys 426, pp. 65-85 : 69-71

Taxon classification Animalia Coleoptera Dytiscidae

Fontidessus aquarupe Miller & Montano sp. n. Figs 2, 10, 17, 24, 32

Type locality.

Guyana, Region IX, Kusad Mts, Mokoro Creek, 2°48.531'N, 59°51.900'W.

Diagnosis.

Fontidessus aquarupe is small (TL = 1.5-1.7 mm), but larger than all Fontidessus species except Fontidessus toboganensis and Fontidessus bettae , which are comparable in size (Figs 1-5). The dorsum is dark with diffuse yellow maculae on the pronotum and elytron. The male genitalia are distinctive. The median lobe is broad and apically broadly pointed and curved dorsad (Fig. 24A, C). The ventral sclerite is long and broad, and apically subtruncate with distinct lateral pointed lobes (Fig. 24B). The lateral lobes are basally broad and apically are elongate and slender (Fig. 25A, D). The prosternal process is relatively broad, flattened and apically narrowly rounded (Fig. 11).

Description.

Measurements. TL = 1.5-1.7 mm, GW = 0.9-1.0 mm, PW = 0.8-0.9 mm, HW = 0.5-0.6 mm, EW = 0.3-0.4 mm, TL/GW = 1.7, HW/EW = 1.5-1.6. Body (Fig. 2) oval, robust, dorsoventrally somewhat compressed; lateral outline nearly continuous between pronotum and elytron; lateral margins of pronotum evenly curved; lateral margins of elytron evenly and broadly curved.

Coloration. Head dark brown; pronotum dark brown, black along anterior and posterior margins, with yellow transverse macula on each side anterior to middle (Fig. 2); elytron brown with diffuse pale areas anteriorly and with posterior extensions along lateral margins and near suture, apex with triangular pale area (Fig. 2). Ventral surfaces black to dark red-brown except prothorax, including prosternal process, yellow; antennae and appendages yellow to yellow-brown.

Sculpture and structure. Head with very fine, inconspicuous, irregular punctation, surface between punctures shiny with distinct microreticulation comprised of minute, isodiametric cells; eyes medium in size (Fig. 2, HW/EW = 1.5-1.6). Pronotal surface similar to head; with posterior angles obtuse; lateral bead narrow, of even width throughout, lateral margins weakly curved; pronotal striae fine, extending nearly 1/2 distance across pronotum (Fig. 2). Elytron with anterolateral angle obtuse, not extended anteriorly (Fig. 2); surface similar to pronotum, covered with fine microreticulation. Prosternal process moderately narrow, flattened, lateral margins posteriorly convergent, apex of process narrowly rounded (Fig. 11); metacoxal process with lateral lobe minute. Pro- and mesotarsi relatively narrow in both male and female, but slightly broader in male. Metatrochanter extremely large relative to metafemur (Fig. 18).

Male genitalia. Median lobe in dorsal aspect elongate, broad, apically abruptly constricted, terminating in two elongate, narrow rami with medial deep, narrow emargination, apex with inconspicuous, diaphanous lobes laterally (Fig. 25A); in lateral aspect slender, elongate, conspicuously recurved with apical portion very slender and apically narrowly pointed (Fig. 25C); with elongate ventral sclerite that is broad and apically truncate, terminating in pointed lobes laterally (Fig. 25B). Lateral lobes elongate, apically abruptly sinuate, basally broad (Fig. 25D).

Variation.

Specimens vary in the extent of dorsal coloration, particularly the extent to which the anterior diffuse elytral macula extends posteriorly along the lateral and sutural margins.

Etymology.

This species is named aquarupe from the Latin, aqua, meaning “water”, and rupe, meaning “rock” or “cliff” since specimens are known from hygropetric habitats.

Distribution and habitat.

Fontidessus aquarupe is known only from seepages and wet rocks near a single site in the Kusad Mountains of southwestern Guaya (Fig. 32).

Material examined.

Holotype in CSBD: male labeled, "GUYANA: Regions IX 2°48.531'N, 59°51.900'W, 170m Kusad Mts., large seepage nr. Basecamp: on wet rocks leg. A. Short & W. Washington GY13-1024-03C/ SEMC1047996 KUNHM-ENT [barcode label]/ HOLOTYPE: Fontidessus aquarupe Miller & Montano, 2014 [red label with black line border]". Paratypes: 69 labeled same as holotype except “… /PARATYPE: Fontidessus aquarupe Miller & Montano, 2014 [blue label with black line border]"; 69 labeled, "GUYANA: Region IX 2°48.531'N, 59°51.900'W 170m Kusad Mts., Mokoro Creek main seepage area leg. Short, Isaacs, Salisbury 27.x.2013; GY13-1027-03B /PARATYPE: Fontidessus aquarupe Miller & Montano, 2014 [blue label with black line border]".