Fontidessus wheeleri Miller

Miller, Kelly B. & Spangler, Paul J., 2008, Fontidessus Miller and Spangler, a new genus of Bidessini from Venezuela (Coleoptera: Dytiscidae: Hydroporinae) with three new species, Zootaxa 1827, pp. 45-52 : 50-51

Fontidessus wheeleri Miller , new species

( Figs 3, 7 , 14–16 )

Type locality. Venezuela, Territorio Federal Amazonas, 40km S Puerto Ayacucho, at El Tobogán, Coromoto.

Diagnosis. This species is smaller than F. toboganensis (TL <1.4mm), but is similar in size (though slightly larger) and external appearance to F. o r n a t u s. Fontidessus wheeleri has the prosternal process elongate with the lateral margins slightly concave and tapered to sharply pointed apex ( Fig. 7 ). The pale regions on the elytron are brighter yellow and more clearly demarcated in F. w h e e l e r i than in F. ornatus which have the elytral maculae more pale and diffuse. The male genitalia are diagnostic with the median lobe broad and deeply bifid in ventral aspect ( Fig. 14 ).

Description. Measurements. TL = 1.2–1.3 mm, GW = 0.6–0.7 mm, PW = 0.5–0.6 mm, HW = 0.4–0.5 mm, EW = 0.2–0.3 mm, TL/GW = 1.7–1.8, HW/EW = 1.6–1.7. Body ( Fig. 3 ) oval, elongate; lateral outline slightly continuous between pronotum and elytron; lateral margins of pronotum gently curved; lateral margins of elytron evenly and gently curved.

Coloration. Head yellow brown, brown along posterior margins and medial margins of eyes; pronotum broadly brown along posterior margin, narrowly dark brown along anterior margin; elytron brown with the following yellow maculae: 1) a basal macula in an irregular band extending posteriorly along suture at medial margin, 2) a lateral longitudinal macula posterior to humeral angle, broader anteriorly and extending posteriorly in narrow band to near apex, 3) a subtriangular subapical macula ( Fig. 3 ). Ventral surfaces of thorax and abdomen dark brown except prosternum, prosternal process, propleuron and pronotal epipleuron yellowbrown; appendages yellow to yellow-brown.

Sculpture and structure. Head with very fine, inconspicuous, irregular punctation, surface between punctures shiny, without distinct microsculpture; eyes medium in size ( Fig. 3 , HW/EW = 1.6–1.7). Pronotal surface similar to that of head, with posterior surface with fine microsculpture; with posterior angles obtuse; lateral bead slender, of even width throughout; pronotal striae finely incised, extending nearly 1/2 distance across pronotum ( Fig. 3 ). Elytron with anterolateral angle obtuse, not extended anteriorly ( Fig. 3 ); surface similar to pronotum, with microsculpture indistinct. Prosternal process elongate and slender, lateral margins slightly concave, apex of process rounded ( Fig. 7 ); metacoxal process with lateral lobe small. Pro- and mesotarsi relatively narrow in both male and female, but slightly broader in male.

Male genitalia. Median lobe in ventral aspect very broad, deeply bifid, with branches broad, subapically strongly constricted on lateral margins, apices sharply pointed ( Fig. 14 ); in lateral broad at base, irregularly narrowed to sharply pointed apex ( Fig. 15 ). Lateral lobe narrow at base, medially expanded, apical portion parallel-sided to slightly expanded, broadly rounded apex, with small series of elongate setae along dorsal margin ( Fig 16 ).

Etymology. This species is named in honor of my good friend and fellow coleopterist, Dr. Quentin D. Wheeler, Arizona State University.

Distribution and habitat. The species is known only from the type locality. Label data indicate the following habitats; “seep,” and “bare rock streambed.”

Material examined. HOLOTYPE in USNM: male labeled, “ VENEZUELA: T.F. Amazonas Puerto Ayacucho (40km.S) at Tobogán, 22Feb1986 P.J. Spangler, Colln.#6/ Bare rock streambed in sunlight; beneath wet leaves at margin/ HOLOTYPE: Fontidessus wheeleri Miller, 2008 [red label with double black line bor- der].” PARATYPES, 1, same as holotype except 23 January 1989, seep at upper shelter, P.J. Spangler, R.A. Faitoute and C.B. Barr, colrs.

Figures

FIGURES 1 – 7. Fontidessus species. 1 – 3) Dorsal habitus, 1) F. toboganensis, 2) F. ornatus, 3) F. wheeleri. 4) F. toboganensis, left metatrochanter and metafemur, anterior aspect. 5 – 7) prosternal process, 5) F. toboganensis, 6) F. ornatus, 7) F. wheeleri. Scale bar a = 1.0 mm for Figs 1 – 4. Scale bar b = 0.1 mm for Figs 5 – 7.

FIGURES 8 – 17. Fontidessus species. 8 – 10) F. toboganensis, male genitalia, 8) median lobe, dorsal aspect, 9) median lobe, right lateral aspect, 10) right lateral lobe, right lateral aspect. 11 – 13) F. ornatus, male genitalia, 11) median lobe and left lateral lobe, dorsal aspect, 12) median lobe, right lateral aspect, 13) right lateral lobe, right lateral aspect. 14 – 16) F. wheeleri, male genitalia, 14) median lobe and left lateral lobe, dorsal aspect, 15) median lobe, left lateral aspect, 16) right lateral lobe, right lateral aspect. 17) F. toboganensis, female genitalia, ventral aspect. Scale bars = 0.1 mm.