Epimetopus mendeli, Fikáček & Barclay & Perkins & Sw, 2011

Fikáček, Martin, Barclay, Maxwell V. L., Perkins, Philip D. & Sw, London, 2011, Two new species of the Epimetopus mendeli species group and notes on its adult and larval morphology (Coleoptera: Hydrophiloidea: Epimetopidae), Acta Entomologica Musei Nationalis Pragae 51 (2), pp. 477-504 : 480-487

Epimetopus mendeli sp. nov.

Type locality. Peru, Cuzco district, Kosñipata Valley, Cock of the Rock Lodge, 71°32′44.6″W 13°03′21.8″S, 1500 m a.s.l.

Type material. HOLOTYPE: J ( UNMSM): ‘ Peru, Cuzco District / Kosñipata Valley / Cock of the Rock Lodge / W71°32′44.6″; S13°03′21.8″ / 20.xi.–15.xii.2009, 1500m / Mendel, H. & Barclay, M.V.L. // BMNH {E} / 2009-126 / under stones/ by torrent’ . PARATYPES: 18 spec. ( BMNH, NMPC, KSEM, MCZ, NHMW, UNMSM): same label data as the holotype ; 9 spec. ( BMNH, NMPC, NHMW, UNMSM): ‘ Peru, Cuzco District / Kosñipata Valley / Cock of the Rock Lodge / W71°32′44.6″ ; S13°03′21.8″ / 20.xi.–15.xii.2009, 1500m / Mendel, H. & Barclay, M.V.L. // BMNH {E} / 2009-126 / light sheet’ ; 1 J ( KSEM): ‘ PERU: Madre de Dios / Panliacolla Lodge [= Pantiacolla Lodge], Monk Saki Trail / Alto Madre de Dios River , 400m / 12°39′22″S, 71°13′55″W / 25 OCT 2000 ; R. Brooks / PERU 1B00 098A ex: at black light’ ; 4 JJ 3 ♀♀ ( USNM): ‘ PERU: Cuzco / Quince Mil / 28 Jan. 1979 / W. E. Steiner’ ; 1 ♀ ( USNM): same label data plus ‘larvae from the egg case / carried by this specimen / used for description by / Fikáček et al. (2011) ’.

Additional adult material examined. 1 ♀ ( USNM): ‘ PERU: Cuzco / 25km SW Pilcopata / 16 Feb. 1979 / W. E. Steiner’.

Description. Body widely elongate ( Figs. 1–2 ), widest at posterior third of elytra, moderately convex in lateral view. Dorsal surface piceous brown, elytra with a pale reddish half-moonshaped spot at ca. posterior 0.4 of intervals 1–5. Ventral surface piceous black, epipleura turning reddish brown posteriorly; antennae reddish with brown antennal club, maxillary palpi reddish with palpomere 4 brown; trochanters and bases of femora dark brown to brown, distal portions of femora and entire tibiae and tarsi reddish. Body length 2.3–3.5 mm (holotype 3.1 mm), body width 1.3–1.8 mm (holotype 1.5 mm).

Head. Clypeus with uniform rather dense granulation, clypeus feebly concave, without marginal rim, lacking ‘systematic punctures’. Frons with granulation similar to that of clypeus, lacking ‘systematic punctures’ at inner margin of eyes. Eyes large, consisting of rather large ommatidia; elongate oval in dorsal view, incompletely divided into dorsal and ventral portion in anterior 0.7 by a wide canthus; ventral portion large, slightly larger than dorsal portion, delimited posteriorly by short but distinct postocular bridge. Gular sutures widely joined in anterior 0.7, widely divergent in posterior 0.3. Labrum large, exposed, lacking granulation and ‘systematic punctures’. Maxillary palpi moderately long, palpomeres 2 and 4 subequal in length, each ca. 2.5× as long as palpomere 3; palpomere 4 strongly asymmetrical, nearly straight on outer margin, widened in basal 0.4 on inner margin; cardo and stipes lacking ‘systematic punctures’. Mentum ca. as long as wide, flat, bearing fine punctation; labial palpus short, basal palpomere the smallest, palpomere 2 ca. half as long as palpomere 3, palpomere 3 lacking spiniform sensillae, bearing only a few pore-like sensillae apically. Antenna with 9 antennomeres; scape slightly longer than antennomeres 2–9 combined, widest at distal margin; pedicel small, bulbous; antennomeres 3–6 very short, subequal in length, antennomere 6 (cupula) not differentiated from antennomeres 3–5 in size and shape; antennomeres 7–9 forming large pubescent club, first club antennomere the shortest and narrowest, 9 th antennomere the longest and widest, ca. as long as antennomeres 7–8 combined.

Prothorax. Pronotum slightly wider than long; anterior lobe large, covering large basal portion of head up to anterior margin of eyes, bearing a deep distinct groove at anterior margin mesally; lateral lobes large, directed anterolaterad, nearly rectangular in shape. Pronotal sculpture consisting of four elevated ridges; two median ones close to each other, slightly sinuate in shape and joining each other anteriorly, high and distinct especially in their anterior third, defining a median groove; lateral ones weak and rather indistinct. Entire surface of pronotum except for medioanterior margin and anterior third of median ridges covered by moderately dense granulation similar to that of clypeus. Prosternum ca. as long as half of procoxal cavity, flat, bearing a reticulate microsculpture on the whole surface with a few isolated granules at midwidth; prosternal process strongly narrowing between procoxae, but widened again posteriorly, joining the hypomeral process posteriorly (hence, procoxal cavities closed posteriorly). Hypomeron divided by a ridge into the lateral narrow granulate portion and large mesal portion bearing the reticulate microsculpture and scattered granules.

Mesothorax. Scutellar shield slightly longer than wide, rounded posteriorly. Elytra narrowest subanteriorly, widest in posterior 0.3. Each elytron with 10 longitudinal punctuate striae, punctures large, close to each other, not connected by a longitudinal tubercles; scutellar stria absent. Each elytron elevated on sutural interval and bearing three additional high elevated ridges on intervals 3, 5 and 7; ridge on interval 5 interrupted in anterior 0.2, ridges on intervals 3 and 7 complete, ridge on interval 7 reaching large humeral bulge; all ridges reaching subapically. Remaining intervals (i.e. those not elevated to ridges) bearing irregular series of scattered granules; ‘systematic punctures’ absent from all elytral intervals. Elytral interval 11 with additional highly elevated ridge forming a false elytral margin in dorsal view. Epipleuron not divided into pubescent inner and bare outer portions, wide throughout, reaching elytral apex. Mesoventrite distinctly divided from mesanepisterna, bearing highly elevated transverse ridge on mesoventral process. Anapleural sutures nearly straight, joining anteriorly; mesanepisterna joining mesally. Anterior collar of mesothorax well defined, widest mesally. Mesepimeron large, subtriangular. Whole ventral surface of mesothorax except for anterior portion of mesoventrite and anterior collar bearing reticulate microsculpture, posterior portions of mesoventrite, mesanepisterna and whole mesepimera with scattered granules. Mesoventral process short, loosely contacting metaventral process.

Metathorax. Ventral portion of metathorax slightly longer than mesoventrite, bearing reticulate sculpture and scattered granules over its entire surface. Metaventral process long and rather wide, projecting far between mesocoxae; anterolateral rim of metaventrite distinct, reaching submesally. Katepisternum very wide sublaterally, divided by very distinct katepisternal suture, bearing large deeply bifurcate metacoxal process. Metanepisternum ca. 7.5× as long as wide, lacking anterior transverse ridge strongly widened and projecting mesad anteriorly (nearly contacting mesocoxal cavity), bent mesad posteriorly and delimiting the outer wall of metacoxal cavity. Posteroventral portion of metepimeron widely exposed sublaterally. Metacoxal cavities not reaching lateral portion of metathorax. Hind wing well developed, with rather large distal area lacking any veins; RP preserved nearly from base, basal cell incompletely delimited due to interrupted AA 3+4, wedge cell well developed, very small, AA 3 well developed, bifurcation of MP 4 and CuA 2 preserved as weak remnants only; jugal lobe preserved.

Abdomen with 5 visible ventrites. Ventrite 1 with large metacoxal grooves covering nearly its whole surface. Ventrites 2–5 flat, lacking pubescence; ventrites 2–3 and anterior portion of ventrite 4 with fine punctation (i.e. having shagreened appearance when examined under the binocular at 90× magnification), posterior portion of ventrite 4 and whole ventrite 5 shiny, without punctation; lateral margins of ventrites 2–4 and posterior margin of ventrite 5 with fine submarginal ridge. Posteromedian portion of ventrite 5 without emargination.

Legs. Profemora widest in basal third, covered with large tubercle-like projections on ventral face, bearing dense pubescence in basal third dorsally; mesofemora apparently widened at midlength, bearing stout decumbent sparsely arranged setae on ventral surface; metafemora long and slender, only indistinctly widened in distal third, ventral surface with same setation as mesofemora. All femora without tibial grooves. Pro- and mesotibiae distinctly longer than femora, metatibiae ca. as long as metafemora; all tibiae narrowest basally, slightly widened subbasally and then conical throughout in meso- and metatibiae, protibiae distinctly widened ca. at midlength; all tibiae bearing series of equidistant series of stout setae, those on inner face of metatibiae longer and thinner than remaining ones. Tibial spurs short, only slightly longer than other spines on tibial apices. Tarsi with five tarsomeres, tarsomere 1 shortest, rather indistinct in ventral view, tarsomeres 2–4 subequal in length, ca. as long as tarsomere 5 when combined; each tarsomere with few stout erect setae ventrally and few short decumbent setae on dorsal face. Claws moderately large, semicircular.

Male genitalia ( Figs. 3 , 26–27 ). Aedeagus 0.9 mm long. Phallobase symmetrical, widely rounded basally, slightly shorter than parameres. Paramere wide throughout, continuously arcuate on outer margin, apex widely rounded. Median lobe narrower than paramere; basal portion narrow, forming ca. 0.4 of length of median lobe, projecting into small lateral and large median projections ca. at midlength; apical portion bilobate, bearing two sets of spines subapically. Sternite 9 with semicircular median portion. Sternite 8 without median anteriaddirected projection.

Variation. The type material varies particularly in size, which seems to be connected to sex (all dissected male specimens are smaller and less robust than female specimens (recognized by the presence of an egg case and/or projecting cerci). The shape of the lateral margin of lateral lobes of the pronotum varies from straight to slightly concave or shallowly excised. The pale spot on the elytra is rather indistinct in several paratypes. All specimens examined are constant in the characters mentioned in the differential diagnosis, including those of male genitalia.

Etymology. The species is dedicated to one of its collectors, Howard Mendel, recently retired Head of Collections at the Natural History Museum, London. His persistence in climbing down the ravine to extend the type series of this new species mirrors his persistence in fighting for the best interests of the Entomology Collections throughout his successful career.

Biology. The holotype and 18 paratypes of this species were collected under loose rocks and rock litter lying on or partly buried in wet gravel substrate, close to the edge of a very fast flowing mountain stream. Males and females (generally with egg cases) were found in groups under stones. The stream flows through good quality cloud forest, but can be accessed by climbing down a ravine beneath a road bridge close to the entrance to ‘Cock of the Rock Lodge’. The habitat is not species-rich, although Oxycheila pseudonigroaenea (Horn, 1938) ( Carabidae : Cicindelinae , det. By F. Cassola) and some smaller Carabidae were abundant, and the Torrent Duck Merganetta armata Gould, 1842 ( Aves: Anatidae ), a predator in fast flowing Andean streams, was present. An additional 9 paratypes of E. mendeli were collected at MV light within a few hundred meters of the stream.

Distribution. The species is known from three rather closely situated localities on the eastern slope of the Andes Mts. in the Cusco and Madre de Dios provinces, Peru.

Figures

Figs. 1–5. General habitus and aedeagi of Epimetopus. 1–2 – E. mendeli sp. nov., general habitus (body length 3.4 mm): 1 – dorsal view; 2 – lateral view. 3–5 – aedeagus of the holotype: 3 – E. mendeli sp. nov., 4 – E. flavicaptus sp. nov., 5 – E. angulatus Balfour-Browne, 1949. Abbreviations: lap – lateral process of median lobe.

Figs. 26–29. Details of the aedeagal morphology. 26–27 – Epimetopus mendeli sp. nov., paratype from the type locality: 26 – ventral view; 27 – dorsal view. 28–29 – E. flavicaptus sp. nov., holotype:28 – ventral view; 29 – dorsal view. Abbreviations: dl – dorsal lobe; vl – ventral lobe.