Belicinus Rhomboideus, a new genus and species of Psepheninae (Coleoptera: Byrrhoidea: Psephenidae) from Belize Author Arce-Pérez, Roberto Author Shepard, William D. Author Morón, Miguel A. text Zootaxa 2012 3157 31 40 journal article 45678 10.5281/zenodo.279694 51ab7190-d4ae-4c04-9e20-05e2c15196a1 1175-5326 279694 Belicinus rhomboideus sp. nov. Arce-Pérez and Shepard ( Figs. 1 –12) Description. Holotype Male: Body oval and depressed; integument reddish-brown; completely covered (Fig. 4) with spread vestiture of long and short reddish-brown setae, with yellow irridescent setae; ventrally longer and darker; frons, pronotal disc, and apical third of the elytron darker; antennae with scape robust and globose; tibiae slender, clearly arched, with tiny teeth in their internal margin. Total length 3.15 mm , maximum humeral length 1.30 mm . Head: long ( Figs. 1 –3), with a longitudinal furrow in the postoccipital region, concave between the eyes; eyes spherical, very prominent; clypeus subtrapezoidal, declivous at an angle of less than 45 degrees from the plane of the frons, distal margin lightly lifted and bent posteriorly; antennae short, filiform to subserrate, 11 antennomeres, hardly reaching the scutellum, scape larger than other antennomeres (globose), pedicel one third as long as scape; labrum (Fig. 3) small with distal margin widely emarginate; maxillary palpus (Fig. 3) short, with 4 palpomeres, slightly longer than first two antennomeres combined, three basal palpomeres subconical, apical palpomere ovoid, slightly depressed with subapical sensorial region, first palpomere shortest, second palpomere 3 times longer than first, third palpomere 0.75 times the length of the second, fourth palpomere 0.25 longer than the second; labial palpus (Fig. 3) very short, with 3 palpomeres, two basal labial palpomeres robust and wide, segment 3 subspherical and shorter. Thorax: pronotum ( Fig. 1 ) trapezoidal (posterior margin 1.15 mm , lateral margin 0.70 mm ); anterior margin arcuate, posterior margin bisinuate and almost as wide as elytral base; lateral margins rounded and unexpanded; with a longitudinal glabrous line and a weak carina on the distal half, with a slight depression on each side; the margins with dark reddish thick setae; prosternum (Fig. 2) short, not elevated, with long and lanceolate prosternal process not reaching anterior half of mesosternum; procoxae globose; femora robust and enlarged in the middle giving them a subtriangular appearance and longer than the tibiae; tibiae (Fig. 5) slender, markedly arched toward exterior, with a series of tiny teeth in the internal margin (Fig. 6), and with small apical posterolateral denticle; tarsi with 5 tarsomeres (Fig. 5,7), basal four tarsomeres notably triangular and emarginate at apex, fifth tarsomere longest, as long as preceding ones together, subcylindrical and stout; first and second tarsomeres with small ventral lobe of spongy vestiture, first one covers basal half of second, second covers two thirds of third but their vestiture extends until the base of fifth; tarsal claws entire, never bifid or split, widely separated, curved downward in apical half, widened at base and without teeth or accessory membranes. Mesonotum with scutellum short, triangular, with apex rounded; elytron reddish-brown, darker on apical third; surface without striae; length (from base to apex of suture) 2.05 mm ; width (across humerus) 1.30 mm , leaving two tergites exposed; mesosternum (Fig. 2) short, mesosternal groove deep for reception of prosternal process; mesocoxae globose, slightly separate, other features of midleg as described above except tibiae without apical tooth. Metasternum bulky, with a longitudinal shallow groove between metacoxae; metacoxae transverse and prominent, other features as described above. Abdomen: slightly convex, with seven sternites (Fig 8), first sternite with an edge on the basal half, posterior margin of first and second sternites sinuate in middle, posterior margin of third and fourth sternites straight, fifth sternite cleary emarginate, sixth sternite widely emarginate (Y-shaped) and hidden under fifth sternite; seventh sternite small and oval, pygidial plate short, oval and convex. Aedeagus: trilobate, ventrally subrectangular (Fig. 9), total length 0.45 mm , parameres subtrapezoidal, shorter than middle lobe, with external margin slightly sinuate, ending in a truncate and emarginate apex, with light membrane, length 0.14 mm ; parameres in dorsal view (Fig. 10) completely united along basal 2/3 and broadly separate in the apical third, length 0.26 mm ; penis in ventral view (Fig. 9) with expanded rhomboidal shape, with (Fig. 11) small spines on the surface, length 0.17 mm , in dorsal view (Fig. 12) triangular with rounded apex and the basal corners pointed; dorsal area of phallobase (Fig. 10) concave, subcylindrical, 0.9 mm long by 0.2 mm of wide. Female : Coloration of the integument and the outer appearance similar to male. Sexual dimorphism is evident in the form and size of the body: the females are more robust (humerus 3.25 mm long by 1.45 mm wide); the clypeus is not upturned; the antennae are short and do not reach the apical margin of the pronotum; the pronotum is clearly subrectangular, wider than long, 1.35 mm by 0.75 mm , and slightly expanded laterally in the posterior half; prosternal process and groove on the mesosternum are very wide, making both procoxae and mesocoxae appear more separated; tibiae straight, tarsi slender, without lobes and vestiture; abdomen ventrally is very wide, abdominal segment 7 subtriangular; genital plates as in ( Fig. 13 ). Variations: Some specimens are darker on the head, pronota and elytra. Measurements (in mm) total body length 2.80 3.15; maximum width 1.25 1.35. FIGURES 1 6. Belicinus rhomboideus sp. nov. 1. Head and pronotum, dosal view. 2. Head and prosternum, ventral view. 3. Labrum and maxillary palpus, ventral view. 4. Midline of pronotum with a fine carina in the distal half. 5 6. Protibiae slender, clearly arched toward the exterior, with tiny teeth on their internal margin. Type material and deposition. Holotype male Belize , Toledo District, Big Fall, Río Grande, 10-I-1995 , WDS-A-1136, W. Shepard leg. ( EMEC ); 17 3, 1 Ƥ ( paratypes same data as holotype ), EMEC (10), IEXA (6), NHNM (2); same data as holotype except 6-I-95 , W. Shepard leg. 2 3, 2 Ƥ ( IEXA ); Belize , Toledo District, 7 miles S Mafredi, 9-I-1996 , Mafredi Cr Trib. WDS-A-1191, W. Shepard leg. 1 3 ( IEXA ); Belize , Cayo District, 16.6 km SE, Belmopan, 3-VIII-1993 , Caves Branch, WDS-A- 982, W. Shepard leg. 3 3, 3 Ƥ ( EMEC ); Belize , Cayo District, 20 mi SE Belmopan, Sibun River, 20-I-93 , WDS-A-946, 2 3, ( IEXA ); Belize , Belize District, 5 mi WNW Belize , 14-I-95 , Mahoganey Creek, WDS-A- 1144, 1 3 , ( IEXA ). FIGURES 7 12. Belicinus rhomboideus sp. nov. 7. First four tarsomeres (dorsal and lateral view). 8. Abdominal ventrites. 9. Aedeagus on ventral view, showing phallobase, parameres and middle lobe (penis). 10. Aedeagus, dorsal view. 11. Aedeagus, close-up of penis, ventral view. 12. Aedeagus, dorsal view. FIGURES 13 22. Belicinus rhomboideus sp. nov. 13. Genital plates of Belicinus rhomboideus sp. nov. 14. Habitus of Pheneps cursitatus . 15. Protarsomeres of Pheneps antennalis . 16. Pronotum showing middorsal carina of Psephenops mexicanus , dorsal view. 17. Ventral aspect of head and maxillary palpus of Psephenops lupita . 18. Ventral aspect of head and maxillary palpus of Psephenopalpus browni . 19. Protarsomeres of Psephenops sp. 20. Protarsomeres of Psephenopalpus browni . 21. Protarsomeres of Psephenotarsis triangularis . 22. Protarsomeres of Psephenus sp. (Fig. 14 from Spangler 1987; Fig. 15 from Spangler and Steiner 1983; Fig. 16 from Arce-Pérez and Novelo-Gutiérrez 2000; Fig. 17 from Arce-Pérez 2002; Fig. 18 from Arce-Pérez 2004b; Figs. 19, and 22 Arce-Pérez and Novelo-Gutiérrez 2001) FIGURES 23 24. Belicinus rhomboideus sp. nov. 23. Larva, dorsal view. 24. Larva, ventral view. Type locality. Belize , Toledo District, Big Fall, Río Grande, 16E16' N 88E53' W. Here the Río Grande is a fast flowing, clear, warm-water stream. The water is more than 1 m deep and flows swiftly over cobbles and boulders. Etymology. The name rhomboideus refers to the expanded, rhomboidal shape of the penis.