Phaenostoma urichi ( Scott, 1912 ) Clarkson & Albertoni & FIKÁýEK, 2014

Clarkson, Bruno, Albertoni, Fabiano Fabian & FIKÁýEK, Martin, 2014, Taxonomy and biology of the bromeliad-inhabiting genus Lachnodacnum (Coleoptera: Hydrophilidae: Sphaeridiinae), Acta Entomologica Musei Nationalis Pragae 54 (1), pp. 157-194 : 186-189

Phaenostoma urichi ( Scott, 1912) comb. nov.

(Figs 12, 75í86)

Cyclonotum urichi Scott, 1912: 435 . Coelostoma Urichi: KNISCH (1924: 113) . Psilodacnum urichi: ORCHYMONT (1937: 134) . Lachnodacnum urichi: HANSEN (1991: 207) .

Type locality. Trinidad and Tobago, Trinidad, El Tucuche.

Type material examined. HOLOTYPE: unsexed specimen ( BMNH): “ Trinidad [handwritten directly on the label with the beetle] // Type [rounded label with red margin] // 1912 – 435 [handwritten] // Bromeliaceae / Tucuche Mt. 3100 ft. / Trinidad / 20. March 12-26. 1912 / H. Scott // Cyclonotum / urichi H. Scott / TYPE”.

Additional material examined (28 spec.): TRINIDAD AND TOBAGO: 1 spec. ( MCZ): Trinidad , Cedros [= Cedros Forest Reserve, ca. 10°7ƍN 61°46ƍW], 4.v.1929, lgt. Darlington ; 1 J, 4 spec. ( BMNH, IRSN, MCZ): Mt. Tucuché [10°44.33ƍN 61°24.64ƍW], without date, lgt. R. Thaxter ; 14 spec. ( MCZ, NMPC): same locality, iv.1929, lgt. Darlington ; 3 spec. ( MCZ): same locality, in bromeliads, iv.1929, lgt. Darlington ; 3 spec. ( BMNH, IRSN): same locality, 14 May 1912, lgt. F. W. Urich ; 2 spec. ( MCZ): same locality, 16.xii.1934, lgt. N. A. Weber .

Redescription. Body length 4.1í 4.6 mm, body width 2.7í 2.9 mm. Body widely oval, weakly convex in lateral view; pronotal and elytral outline continuous in dorsal and lateral views. Entirely black in dorsal and ventral views; antennae, maxillary and labial palps pale brown. Coxae, femora and tibiae brown, tarsi pale brown.

Head. Clypeus (Figs 78, 80) wide anteriorly, only slightly narrowing before eyes, with anteromedian margin truncate. Frontoclypeal suture conspicuous. Clypeus and frons ¿nely punctuate, the punctures are about a third the width of one ommatidium, interstices with microsculpture: reticulate on anterior margin and with ¿ne transverse longitudinal ridges medially on clypeus, reticulate on posterior margin of head; lateral portions of frons between anterior margin of eye and frontoclypeal suture lacking punctuation, only with sparse micropunctures. Eyes small, not protruding laterad, oval in dorsal view, surrounded by micropunctures, separated by 7× the width of one eye, distinctly emarginate anteriorly in lateral view. Labrum small, membranous, totally concealed under clypeus, ca. 0.6× as wide as maximum width of head. Mentum 1.4× as wide as long; surface bearing dense long yellow setae; lateral margins nearly parallel-sided, each bearing row of setae; anterior margin deeply bisinuate. Maxillary palps with four palpomeres, short and rather stout; palpomere 1 minute, palpomeres 2 and 4 subequal in length, slightly longer than palpomere 3; palpomere 2 very wide, somewhat bulbous; palpomere 3 slightly curved inwards and widened distally; palpomere 4 narrowest. Labial palps with three palpomeres: palpomere 2 bearing dense brush of long setae on its outer face anteromedially. Labial palpomere 3 about 0.8× as long as palpomere 2, much narrower. Submentum pubescent. Gula slightly constricted between tentorial pits.Antenna (Fig. 85) with nine antennomeres; scape about as long as pedicel and antennomeres 3í6, its basal portion bent dorsally; pedicel cylindrical; cupula large and short, bare, concealing basal portion of antennomere 7; antennal club loosely segmented, depressed dorsoventrally, densely pubescent with few longer and thicker setae on sides and on distal margins of antennomeres.

Prothorax. Pronotum weakly convex, with bead on anterior and lateral margins including antero- and posterolateral corners; anterior and posterior corners weakly angulate; posterior margin slightly arcuate. Prosternum ( Fig. 82 ) not carinate medially, weakly convex. Procoxal cavities large, opened posteriorly, anterolateral aperture of procoxal cavity opened. Hypomeron with very large pubescent inner portion, marginal glabrous portion rather narrow ( Fig. 82 ).

Mesothorax. Mesoventrite completely fused with anepisternum 2, anepisternal suture absent (Figs 79, 81); epimeron 2 well delimited, divided from anepisternum 2 by a suture, pubescent; anterior collar of mesothorax broad, well demarcated. Mesoventrite highly elevated medially into preepisternal plate; preepisternal plate longitudinal and linear, somewhat tectiform with the sides sloping laterally, bare; bearing sparse long setae in ventral view, narrowly attaching metaventral process, not forming a common keel with it; surface of preepisternal plate nearly straight, as laying slightly lower than the surface of metaventrite; anteromedian pit-like groove present, partly overlapped by anterior portion of preepisternal plate. Grooves for reception of procoxae weakly de¿ned (Figs 79, 81). Elytron highly convex; lateral margin beaded along its length, very narrowly explanate on posterior half; elytral series of punctures absent; elytral surface smooth, homogenously punctated, punctation as dense as on pronotum, denser than on head; punctures slightly larger than the pronotal ones. Sutural stria very weak, rather indistinct, developed only on distal portion of elytron, not reaching elytral apex. Epipleuron wide and strongly inclined throughout, very wide anteriorly, strongly narrowing posteriorly; outer bare portion (= “pseudepipleuron”) about 0.3× as wide as inner pubescent portion (= “epipleuron”) in basal third, about 0.6× as wide as inner pubescent portion in distal two-thirds. Mesocoxal cavities transverse, narrowly divided medially by meso-metaventral keel.

Metathorax. Metaventrite with pubescent surface, slightly elevated into a longitudinal bare plate medially; median plate projecting anteriorly into a rhomboid metaventral process situated above level of mesoventral plate in lateral view (Figs 79, 83); meso-metaventral plate constricted at junction. Posterior half of metaventral keel with weak longitudinal groove. Median bare portion of metaventrite with scattered punctures in anterior part and somewhat on posterior margin. Metepimeron rather large with long posterior projection. Hind wing (Fig. 12) with R-M loop distally the maximum width of the wing; RA 3+4 reduced, not attached to RA basally, forming an opened radial cell; radial cell large, subrectangular, pigmented on anterior two-thirds; r3 absent; r4 developed, but is not attached to R-M loop, and not connecting RA 3+4 to R-M loop; apical ¿eld with RA 3 well de¿ned, short, not reaching the margin of the wing apically; RA 4 fused with RP 1, together forming a pigmented area almost reaching wing margin apically; base of RP 1 far of R-M loop; RP 2 very weak, forming a triangular pigmented area, almost reaching R-M loop basally and is almost invisible distally; RP 3+4 very weakly de¿ned, narrow and long, beginning from R-M loop, near to the base of medial spur, curved posteriad and reaching wing margin apically; medial ¿eld with medial spur reduced; MP 3+4 developed, nearly connected with MP 1+2, not attached to MP 3 and MP 4 +CuA 1; MP 3 and MP 4 +CuA 1 well de¿ned, connected basally, and attached with CuA 1, reaching wing margin posteriorly; CuA 1 developed, without connection with MP 3+4, but connected with MP 3 and MP 4 +CuA 1; CuA 2 present and well de¿ned, reaching the posterior edge of the wing apically; Cu in this genus is longer than observed in Lachnodacnum ; CuA 3+4 absent and hence wedge cell missing; AA 3 and AA 4 de¿ned and long, nearly reaching posterior margin of the wing; anal ¿eld with venation reduced, composed of a long AP

3+4

and with AP

1+2

absent.

Legs. Procoxa globular, pubescent; profemur with deep tibial groove delimited by high ventral and low dorsal ridges, ventral surface pubescent except for small bare distal area; protibia cylindrical, bearing series of stout spines and irregularly arranged small spines, distal portion bearing “crown” of smaller stout spines and two large spurs. Mesotrochanter slightly sinuate on posterior margin; ventral surface of mesofemur bare, only with few scattered long setae on anterior and posterior margins, its surface reticulated; tibial groove deep, developed throughout, delimited by high ventral and low dorsal ridges; mesotibia flattened, sparsely covered by short and stout spines, bearing longitudinal series of larger spines and a subapical transverse series of larger spines; distal apex with series of short spines and two long spurs on inner margin. Metatrochanter slightly sinuate on posterior margin, pubescent on basal portion; metafemur large and wide, ventral surface bare except of sparsely arranged setae on extreme anteroproximal portion, surface reticulated with scattered setiferous punctures; tibial groove well developed, deep, delimited by high ventral and low dorsal ridges. Metatibia flattened, bearing scattered short spines and two series of larger spines on outer margin; distal half with transverse series of moderately long spines and two long spurs on inner margin. Tarsi much shorter than tibiae, each tarsomere bearing a dense brush of long setae ventrally (Fig. 86), with longer setae sideward and with single to few long setae dorsally. Metatarsus slightly compressed laterally, metatarsomere 1 slightly longer and ca. twice wider than metatarsomere 2; claws small, simply arcuate.

Abdomen. With ¿ve ventrites, all ventrites flat, without any longitudinal carina; posterior margin of ventrite 5 without apical notch nor the median group of stout setae.

Male genitalia (Fig. 17). Aedeagus 0.65 mm long. Phallobase symmetrical, extremely short, with very long and distinctly detached manubrium. Parameres rather narrow basally, slightly bent mesally, gradually narrowing towards apex. Median lobe wide basally, bearing two long and wide basal projections, slightly widening towards basal 0.4, then abruptly strongly narrowing into an extremely narrow apical portion; apex rounded, gonopore distinct, situated in apical third. Sternite 9 moderately wide basally, bearing rather wide tongue-shaped median projection, lateral struts arcuate, slightly shorter than median portion.

Differential diagnosis. Phaenostoma urichi may be distinguished from all other described species of the genus by the following characters: body larger than 4.0 mm (smaller than 4.0 mm in remaining species), eyes very small, separated by 7× the width of one eye in dorsal view (Fig. 78) (eyes larger, separated by 4í5× the width of one eye in dorsal view in remaining species), clypeus very wide, only slightly narrowing anteriad, straight on anterior margin (Fig. 78) (clypeus strongly narrowing anteriad, arcuate on anterior margin in remaining species) and median lobe of the aedeagus very narrow apically, gonopore situated in apical third (Fig. 17) (median lobe wide apically, gonopore subapical in other species). See GUSTAFSON & SHORT (2010) for details about the remaining species.

Biology. The type specimens were collected between the leaf bases of the epiphytic Tillandsia sp. (Bromeliaceae) in the tropical montane forest ( SCOTT 1912). Part of the non-type specimens from Mt. Tucuché also bear a label indicating they were collected in bromeliads.

Distribution. The species is known from two rather distant localities in Trinidad, and is likely distributed throughout the island in suitable habitats.

Figures

Figs 82í86. Phaenostoma urichi (Scott, 1912), SEM micrographs. 82 – prothorax in ventral view (prosternum and hypomeron); 83í84 – mesoventral elevation (83 – lateral view; 84 – ventral view); 85 – antenna; 86 – protarsus.