Lutrochus funkae, Maier, Crystal A. & Short, Andrew Edward Z., 2014

Maier, Crystal A. & Short, Andrew Edward Z., 2014, Review of the Lutrochidae (Coleoptera) of the Guianas and Lesser Antilles, with description of four new species, Zootaxa 3895 (1) : -

Lutrochus funkae n. sp.

( Figs. 2 , 3–6 )

Type Material. Holotype male: “ GUYANA, Lethem (30kmSE)/ Moco Moco River; 3° 21′N, 59° 28′W / 6 Apr 1994 / PJSpangler, coll[ectio]n #19” “ Lutrochus / n. sp.?/ funkae ” “♀ 4.66 mm long/ 2.53 mm wide” “ HOLOTYPE / Lutrochus / funkae / P.J. Spangler” “♂ tail to YTS/ to draw” “ PHOTO VOUCHER/ PV/ Short Lab KU NHM” “ USNM ENT / 00717778” Holotype deposited in USNM.

Diagnosis. This species most closely resembles L. maldonadoi Maier & Short, 2013 , but can be distinguished from this species by the lateral edge of the pronotum, which is not explanate ( Fig. 3 ); the hind tarsi, which are only clothed with setae towards the base (as opposed to entirely pubescent in L. maldonadoi ); and the distinctive male genitalia ( Fig. 6 ). Lutrochus funkae can be distinguished from L. wao and L. grenadaensis by the following combination of characters: pro-, meso-, and metathoracic legs two-toned, elytral epipleuron parallel-sided, and apical tarsomere testaceous apically, dark brown basally.

Description. MALE. Length 3.9 mm; width 2.1 mm. Body ovate and slightly convex, dark brown to black, densely pubescent; clothed with short, fine, erect golden setae ( Fig. 3 ).

Head broad, broadly rounded, very weakly grooved beneath eye for reception of antenna. Eye rounded, small, with short, golden interfacetal setae; eyes slightly bulging from outline of head. Antenna short, reaching slightly past anterior border of pronotum; antennomeres 1–3 testaceous, antennomeres 4–11 brunneous; antennomeres short and clavate, clothed with short golden setae. Frontoclypeal suture indistinct. Clypeal margin straight. Apical margin of labrum broadly rounded, with golden apical setal brush, lateral setae twice as long as medial setae; labrum clothed with sparse and short golden setae. Mandibles large, dark brown, sickle-shaped; apex of mandible with 2 distinct teeth. Maxilla with 4-segmented palpus, apical palpomere flattened and rounded-triangular. Labial palpus 3-segmented; apical palpomere cylindrical.

Pronotum pubescent, dark brown, 1.9 times as wide at base as long, bisinuate at base ( Fig. 3 ). Lateral edge of pronotum with distinct bead, only very slightly explanate apically. Posterior margin straight anterior to scutellum. Disc broadly convex. Scutellum triangular, as wide as long; clothed in recumbent golden setae. Hypomeron excavate posteriorly to accommodate profemur.

Elytron pubescent, clothed in dense, short, recumbent golden setae, medium brown, widest at anterior half, posterior half gently rounded, coming to an rounded point at apex. Elytron shallowly convex, densely punctate with very fine, shallow punctures, punctures randomly scattered, not arranged in rows; humerus not at all protuberant ( Fig. 3 ). Lateral edge with distinct and weakly sinuate bead ( Fig. 5 ). Elytron lacking faint sutural stria in apical third. Elytral apex rounded, but slightly acuminate.

Prosternum transverse, approximately two times as wide as long; anterior edge with weak bead, deflexed to accommodate withdrawn head; prosternal process about as wide as long, without bead laterally, acute posteriorly ( Fig. 4 ). Disc of prosternum with carinae to accommodate profemora laterally. Metaventrite (?) pubescent, disc fully clothed with setae. Epipleuron excavated to accommodate folded front and middle legs. Epipleuron nearly parallel-sided, extended posteriorly to metacoxae.

Legs long and slender, dorsally testaceous, dark brown ventrally. Procoxae transverse. Profemur densely pubescent, reddish-brown dorsally, medium brown ventrally, strongly excavate ventrally to receive protibia. Protibia entirely pubescent, excavate dorsally to receive protarsus, only slightly explanate. Protarsus with basal four tarsomeres densely pubescent, lacking tufts of long golden setae ventrally; apical tarsomere as long as preceding four tarsomeres combined, glabrous ventrally, pubescent nearly to apex dorsally ( Fig. 5 ). Mesocoxa with tuft of short golden setae basally. Mesofemur fusiform, densely pubescent posteriorly, becoming less so anteriorly, reddish-brown dorsally, medium brown ventrally. Mesotibia completely glabrous, with few scattered setae, lacking small patch of short golden setae at apex; lateral margin not expanded, tibia rounded in cross-section, lacking distinct longitudinal carinae; apex with excavation laterally for reception of mesotarsus. Mesotarsus with all tarsomeres entirely glabrous; apical tarsomere as long as preceding four tarsomeres combined. Metacoxa with single weak posterior projection. Metatrochanter globose, excavate posteriorly. Metafemur densely pubescent. Metatibia entirely pubescent, except for a narrow, longitudinal glabrous band dorsally; with short, golden setae, apex with distinct, distally-facing fringe of setae. Metatarsus with basal four tarsomeres entirely pubescent; apical tarsomere pubescent only in basal 1/4 as in Fig 5 , as long as previous four combined.

Abdomen densely pubescent, with five ventrites ( Fig. 4 ). First ventrite shallowly excavate for reception of folded hind legs, excavation reaches nearly to posterior edge of ventrite. Apical ventrite broadly rounded. Genitalia as illustrated, basal piece + parameres 1.6 mm long. Aedeagus slender and only slightly curved, becoming more curved at base. Parameres fused, pointed, with short distinct lobes interiorly subapically, lobes not extended at apex ( Fig. 6 ).

Female. The female of this species is unknown. Curiously, the holotype possesses a label that states: “♀ 4.66 mm long; 2.53 mm wide,”though Spangler’s field notes indicate that this was the only specimen of Lutrochus collected on the expedition. Additionally, a thorough search of the Smithsonian’s aquatic beetle collection did not turn up any more individuals.

Intraspecific Variation. This species is only known from a single specimen.

Etymology. This species is named “ funkae ” in honor of botanist Vicki Funk, who was instrumental in leading the Smithsonian expeditions to Guyana, on one of which this specimen was collected.

Habitat and Distribution. The single known specimen of the species was collected from leaf packs in the sandy and gravelly Moco Moco River in Guyana (Spangler, in litt.). The Moco Moco River is a small tributary of the Takutu River, near Lethem, Guyana, and lies just east of the border with Brazil ( Fig. 2 ). This area, in the Rupununi savannah region, is mainly grassland habitat.

Remarks. This species was discovered as new and named by Paul J. Spangler, who passed away before describing it.

Figures

FIGURES 1 – 2. 1. Map of northeastern South America showing collection localities of L. funkae, L. leeanneae, L. grenadensis, and L. wao. 2. Habitat of L. wao, collected in partially submerged leafpacks that were caught behind a fallen branch in a flowing forested stream.

FIGURES 3 – 6. Lutrochus funkae n. sp.: 3. Habitus, dorsal view; 4. Habitus, ventral view; 5. Habitus, lateral view; 6. Aedeagus, dorsal and lateral views (scale bar = 1.0 mm).