Neoeubria, Shepard & Barr, 2014

Shepard, William D. & Barr, Cheryl B., 2014, Neoeubria inbionis Shepard & Barr, a new genus and new species of Neotropical water penny beetle (Coleoptera: Psephenidae: Eubriinae), with a key to the adult Eubriinae of the Neotropic Zone, Zootaxa 3811 (4), pp. 553-568 : 554-564

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Neoeubria gen. n.

Type species. Neoeubria inbionis sp. n.

Adult description. Body elongate oval, dorso-ventrally flattened ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ); 4.6–5.6 mm long; densely setose, with pale blond setae forming a pattern of irregular bands and patches over darker integument.

Head deeply withdrawn into prothorax, hypognathus. Eyes finely faceted, very prominent ( Figs. 3–4 View FIGURE 3 View FIGURE 4 ). Frons narrow, between eyes less than width of eye in male, wider than eye in female; hour-glass shaped between eyes; surface densely and confusedly granulate (distance between granules variable) and densely setose; antennal ridges raised above plane of frons; no visible frontal-clypeal suture. Clypeal disc at 90 º to frontal disc, surface densely and confusedly granulate and densely setose, lateral and apical edges margined, apical edge slightly emarginate, apicolateral corners rounded. Labrum very short and transverse. Mouthparts not visible between labrum and apex of prosternum except for palpi. Maxillary palpus with three visible palpomeres; antepenultimate palpomere elongate-conical, setose; penultimate palpomere as long as wide, setose; ultimate palpomere as long as antepenultimate palpomere, cultriform, setose. Labial palpus with two visible palpomeres, half as long as maxillary palpus; ultimate palpomere cultriform, setose. Antenna with 11 antennomeres; pectinate in male ( Fig. 3 View FIGURE 3 ), serrate in female ( Fig. 4 View FIGURE 4 ); antennomere 1 basally constricted, globular beyond, setose; antennomere 2 very short; antennomeres 3–10 with lateral projections; in male projections long, thin and originating basally on antennomeres 4–10, in female projections short, wide and originating apically on antennomeres 3–10; surface microgranulate, very setose; antennomere 11 elongate, surface as on preceding antennomeres.

Pronotum broader than long, widest just anterior to base, narrower than elytra. Apical edge emarginate, smooth. Apicolateral corners right-angled. Lateral edges serrate, margined and slightly explanate. Basolateral corners greater than a right angle, covered by setae. Basal edge finely and densely crenulate to pectinate, gently bisinuate, straight medially anterior to scutellum. Disk raised posterior to head, sloping toward lateral edges; densely and confusedly granulate, granules separated by own width or more; densely setose. Propleura (= hypomeron) wide, concave, shiny; with widely scattered granules and long setae; narrow, acutely-tipped posterior projection extending medially along posterior margin of procoxa making procoxal cavity half-closed.

Scutellum broadly pentagonal, flat; disc granulate and setose as on pronotum; setae more dense on male. Basal edge finely and densely crenulate to pectinate, teeth interdigitating with those on pronotum.

Elytra together longer than wide, widest slightly beyond middle; integument medium brown, covered with patches of brown and blond setae. Basal edges finely and densely crenulate to pectinate, teeth interdigitating with those on pronotum. Basolateral corners wider than pronotum, humeri gently curved. Disc flat, sides sloping downward; lateral edges slightly explanate; slightly serrate basally, smooth thereafter to apex. Ten striae per elytron; each stria a line of closely spaced granules; innermost stria very short (10 or fewer granules), extending posteriorly from scutellum a short distance; remaining striae complete, parallel to near end of elytron where they join each other. Setation of two types: fewer, longer setae that project up off the elytron and very numerous, shorter, recumbent setae; both types of setae having patches of lighter and darker setae; all recumbent setae on adjacent strial intervals oriented either anteriorly or posteriorly, giving a striped appearance. Epipleuron concave; widest basally, tapering to apex; only long setae present; granules absent.

Prosternum wider than long, extending laterally no further than outer edges of procoxae; raised in middle and sloping to lateral edges. Anterior edge smooth, projecting forward to cover mouthparts and ventral margins of eyes. Lateral edges emarginate in male, straight in female. Posterior edges straight laterally, medially wrapping around inner margins of procoxae to form a long narrow prosternal process between. Prosternal process within a deep medial cleft extending one-third the length of the mesoventrite. Procoxal cavity open at medial half. Prosternal disc shiny, with scattered granules and numerous long setae.

Mesoventrite about as wide as long; broadly Y-shaped; anterior half raised in middle; median sulcus deep and wide anteriorly to receive prosternal process, shallow and narrow posteriorly. Anterior edge bicurved, forming long anterolateral arms along anterior border of mesanepisternum. Lateral edges highly curved, smooth. Posterior edges bisinuate, curving around trochantins and mesocoxae forming a medial mesoventral process between. Mesoventral process extends no further than mesocoxae. Mesocoxae broadly open. Mesoventral disc shiny, with scattered granules and numerous long setae. Mesanepisternum and mesepimeron twice as wide as long, subquadrate; disc flat, shiny, covered with short clothing setae.

Metaventrite three times wider than long, irregularly rectangular. Anterior edge bicurved around mesocoxae; lateral edges straight; posterior edge mostly straight except for two small medial teeth adjacent to midline. Disc surface punctate, covered with numerous long setae; medial, longitudinal, glabrous line ending in a deep depression anterior to and between metacoxae; short, transverse suture parallel to posterior edge and just anterior to medial teeth. Metanepisternum elongate, subquadrate; disc flat, punctate, covered with long setae and with scattered granules in anterolateral corners. Metepimeron reduced to small triangular plate at posterolateral corner of metanepisternum; disk covered with setae.

Prothoracic leg with procoxa transverse, swollen in middle, long setae on surface; trochantin exposed, with a small patch of very short projecting setae. Trochanter short, triangular, with long setae. Femur elongate, covered with long, pale setae; ventrally flattened to receive tibia when leg is retracted, flattened area bordered by longitudinal ridges of equal height on either side. Tibia elongate, punctate, covered with long, pale setae; with two rows of stouter darker setae along lateral aspect; two stout apicomedial spines slightly overlapping base of tarsus. Tarsus with five tarsomeres; all tarsomeres covered with long, pale setae; tarsomeres 2–3 with ventral dense patch of shorter, pale setae; tarsomere 1 elongate; tarsomeres 2 and 3 half the length of tarsomere 1; tarsomere 4 very short, not extending beyond end of tarsomere 3; tarsomere 5 as elongate as tarsomere 1. Claws simple in both sexes; angulate at base.

Meso- and metathoracic legs similar to prothoracic leg except metacoxa very transverse and grooved for reception of femur.

Abdomen with five visible ventrites; ventrites all short and very transverse, covered with long setae; apex of ventrites I–IV straight and smooth, apex of ventrite V evenly rounded in both sexes.

Egg Description. Egg oval, approximately 1.2 x as long as wide; 0.313 –0.350 mm long, 0.25–0.313 mm wide. Chorion covered with small polygons.

Larval description. Body a very elongate oval ( Figs. 5–6 View FIGURE 5 View FIGURES 6–9. 6 ), flattened; mature larva 9 mm long and 3.6 mm wide, widest at metanotum; pairs of lateral processes, derived from margins of nota and terga, present on mesothorax, metathorax and abdominal segments I–VIII; four prominent longitudinal dorsal ridges; head and legs not visible dorsally. Dorsal color yellow; brown markings on thorax and abdominal segments 1–9 ( Fig. 5 View FIGURE 5 ); ventral color all yellow or all white. Dorsal surface covered with plastron; plastron setae ( Figs. 7–8 View FIGURES 6–9. 6 ) flat and rounded with scalloped margins, scattered granules visible below plastron. Lateral margins with two types of setae: a dense fringe of fused, shorter, plumose, white setae ( Fig. 10 View FIGURES 10–13. 10 ) and occasional very long, filiform, golden setae ( Fig. 11 View FIGURES 10–13. 10 ), both dorsal and ventral to previous row. Four longitudinal ridges on dorsum, two medial and two sublateral.

Pronotum ( Figs. 6 View FIGURES 6–9. 6 , 13 View FIGURES 10–13. 10 ) with smoothly curved edges; posterior margin smooth except for spinose setae along margin; two medial ridges parallel to longitudinal axis, two sublateral ridges diverging from anterior to posterior ( Figs. 5–6 View FIGURE 5 View FIGURES 6–9. 6 , 13 View FIGURES 10–13. 10 ); disc covered with plastron ( Figs. 7–8 View FIGURES 6–9. 6 ) except over brown markings, thin medial line, and around setae. Mesonotum similar to pronotum except short and transverse ( Figs. 6 View FIGURES 6–9. 6 , 12 View FIGURES 10–13. 10 ), lateral margin with a pair of quadrate processes; gap between lateral processes of pro- and mesonotum covered by dense setal row ( Fig. 13 View FIGURES 10–13. 10 ). Metanotum similar to mesonotum.

Abdominal segments similar to thoracic nota except posteriorly increasingly narrower ( Fig. 5 View FIGURE 5 ); segments I–VIII each with a pair of elongate, apically rounded, lateral processes; brown, spot-like markings only between medial and sublateral ridges; ridges taller than on thoracic nota. Segment VIII shortest; with spiracular cones just lateral to end of sublateral ridges and medial to lateral processes; spiracular cones present in all instars examined. Segment IX longest (but shorter than pronotum), broadly subtriangular ( Fig. 14 View FIGURES 14–17. 14 ), apex evenly curved; disc brown in color; sublateral ridges absent; plastron setae projecting up off surface except around plumose setae ( Figs. 14–15 View FIGURES 14–17. 14 ); marginal setae of two types; anterolateral corners with a dense spiracular brush ( Fig. 9 View FIGURES 6–9. 6 ).

Venter highly membranous except for tip of tarsungulus; surface densely setose. Head withdrawn into pouch to middle of labium ( Figs. 16–17 View FIGURES 14–17. 14 ), tips of antennae and maxillary palpi protruding; anterior margin of cervical area and venter of head heavily setose. Epicranial suture absent. Frontal area heavily setose, especially over stemmata; setae stout, recumbent and projecting anteriorly; one pair of very long setae projecting dorsally; anterior margin broadly emarginate in an arc. Antenna with four antennomeres; antennomere 1 short, as long as broad; antennomere 2 several times longer than broad; antennomere 3 as long as antennomere 2, bearing a stout seta adjacent to and as long as antennomere 4; antennomere 4 very small, four times longer than broad. Clypeus transverse; anterior margin straight; disc setose. Labrum transverse, as long as clypeus; basal half smooth, with no setae; apical half very setose, setae ramose. Mandible with three teeth, teeth black at tips; prostheca plumose. Maxilla with cardo transverse; stipes elongate, rectangular, apically with ramose setae; lacinia and galea cultriform and fused to stipes, apex of each with dense fringe of ramose setae; palpus with four palpomeres, each palpomere about as long as broad. Labium trapezoidal, wider at base; mentum basally with an elongate medial tubercle, apical half covered with long, highly ramose setae ( Figs. 16–19 View FIGURES 14–17. 14 View FIGURES 18–21. 18 ); prementum very short; palpus very short, with two palpomeres.

Prosternum with posterior sternum trapezoidal, wider anteriorly; pleural area divided into three sclerites. Coxal cavities broadly open. Legs five-segmented ( Fig. 20 View FIGURES 18–21. 18 ); coxa conical; trochanter longer than femur; tibia as long as femur, long setae present apically and ventrally; tarsungulus stout and angular basally ( Figs. 20–21 View FIGURES 18–21. 18 ). Mesosternum and metasternum similar to prosternum except pleurites longitudinally rectangular.

Abdominal sternites I–VIII broadly transverse; sternopleural sutures present; tergopleural sutures present at base of lateral processes; entire surface setose except for narrow, bare transverse sulcus, entire or divided in two. Abdominal sternite IX broad; sternopleural sutures present along base of operculum; operculum ( Fig. 22 View FIGURES 22–23. 22 ) almost parallel-sided in basal half, circular apically, apical margin with setal row; two accessory sclerites on each side of basal half of operculum, a short basal sclerite and an elongate apical sclerite; setose ( Fig. 23 View FIGURES 22–23. 22 ) with a mixture of upright plumose setae and recumbent lily-pad-like setae.

Pupal Description (Female). Body ( Fig. 24 View FIGURE 24 ) exarate; elongate-oval; widest at abdominal segment III; 8.5 mm long and 4 mm wide. Color pale yellow. Prothorax, elytra and wings wrapping around to venter; elytra covering wings. Long curved setae in two medial rows on abdominal segments I–VII. Lateral processes on abdominal segments I–VIII; lateral processes on segment I projecting laterally; processes on segments II–VIII recurved postero-laterally but short and blunt; all processes fringed by long unfused setae; processes on segment IX fused to tergum. Pairs of spiracular tubercles on segments II–VII, emerging from the base of each process; tubercles on segment VII longest and most projecting; spiracles slit-like. Abdominal terga with scattered granules; posterior row of setae on each side from lateral process nearly to longitudinal medial row of curved setae. Abdominal tergum IX trapezoidal; disk densely covered with scale-like setae; lateral and apical margins with dense row of long white setae; apex broadly emarginate; ends spinose.

Venter white; membranous. Anterior margin of prothorax with dense row of long setae; propleura broad, reaching eyes. Antennae wrapping extremities of legs but not reaching lateral margins. Legs folded with tarsi along midline. Elytra wrapped around ventrally, covering much of wings and metathoracic legs; three rows of long setae along longitudinal axis of each elytron. Abdominal sterna I and II covered by elytra and metathoracic legs. Abdominal sterna III–VII broadly transverse; heavily setose, especially on lateral margins. Abdominal sternum VIII similar to preceeding sterna except much shorter. Abdominal sternum IX trapezoidal and heavily setose.

Etymology. Neo - from Neotropics; - eubria from type genus of the subfamily Eubriinae . The name is feminine singular.

Differential diagnosis. Neoeubria is defined by the following set of psephenid character states. ADULT: Posterior margin of pronotum and anterior margin of elytra and scutellum crenulate to serrate; elytra granulate in striae; 10 striae per elytron; antennae pectinate in male and serrate in female; claws angulate at base and simple in both sexes. LARVA: Very elongate oval body; four longitudinal dorsal ridges; all lateral processes project laterally; spiracular cone of abdominal segment VIII emerging from tergum, not end of lateral process; margin of abdominal segment IX entire; operculum circular apically. PUPA: Large (8.5 mm long); two medial longitudinal rows of long curved setae on abdominal segments I–VII only; lateral processes of abdominal segments short, recurved, blunt; spiracular tubercles emerging from abdominal terga II–VII near base of lateral processes; elytra with only three rows of setae.

Of all eubriine genera, Neoeubria shares most character states with the East Asian genus Macroeubria Pic. However , Macroeubria differs in the following ways. ADULT: Male antenna serrate (male antenna pectinate in Neoeubria ); pronotal granules in reticulae or vermiculae (granules randomly distributed in Neoeubria ); scutellum without granules and triangular (granulate and pentagonal in Neoeubria ); elytra with nine elytral striae (10 striae in Neoeubria ); mesoventrite densely granulate (only scattered granules in Neoeubria ); metaventrite with granules in reticulae (metaventrite punctate, not granulate in Neoeubria ); male claws bifurcate (male claws simple in Neoeubria ). LARVA: Lateral processes of abdominal segments sharp and recurved (straight and not recurved in Neoeubria ); operculum rectangular and tapering slightly from base to apex (operculum parallel-sided in basal third and circular beyond in Neoeubria ); abdominal segment IX apically emarginate (apically entire in Neoeubria ). PUPA: Smaller, 5 mm long (longer, 8.5 mm long in Neoeubria ); dorsomedial rows of setae from pronotum to abdominal segment VIII (setae only on abdominal segments I–VII in Neoeubria ); several rows of setae on elytra (only three rows in Neoeubria ); lateral processes on abdomen long and sharp-tipped (short and blunt in Neoeubria ); spiracular tubercles long (short in Neoeubria ); abdominal tergum IX elongate and bifurcate apically (short, broad and emarginate apically in Neoeubria ).

Key to adults of Neotropical genera of Eubriinae 1

1 Posterior margin of pronotum and anterior margin of elytra and scutellum smooth................. Eubria , or near Eubria

1' Posterior margin of pronotum and anterior margin of elytra and scutellum crenulate................................ 2

2 Elytra punctate, not granulate.................................................................. Tychepsephus

2' Elytra granulate, not punctate........................................................................... 3

3 Granules on elytra confined to striae............................................................... Neoeubria

3' Granules on elytra not confined to striae..................................................... Dicranopselaphus