Plectromerus ramosi Micheli & Nearns, 2005

Micheli, Charyn J. & Nearns, Eugenio H., 2005, Two new species of Plectromerus Haldeman (Coleoptera: Cerambycidae) from the West Indies, Zootaxa 1028 (1), pp. 23-36 : 30-33

Plectromerus ramosi Micheli & Nearns , new species

Figs. 2d–h , 3b

Description. MALE. Length 4.3–6.5 mm, width 1.0– 1.6 mm (measured across humeri). Small, narrow, subcylindrical. Integument ferrugineus, varying from light to dark, with two testaceus maculae (sometimes transverse fasciae) on each elytron, one at basal third, small, and oblong, and another just behind middle, this one oblique. Head with front nearly flat, transverse, with a median, shallow line from between eyes and antennal tubercles, slightly concave between antennal tubercles, which are slightly raised and widely separated. Surface moderately shining, with fine wrinkles, coarsely, rugosely, densely,

confluently punctate, punctures shallower beyond vertex. Head with a fine, short pale seta in each puncture and a few scattered long, pale, suberect hairs. Eyes prominent, transverse, subreniform. Antennae 11­segmented, slightly longer than body, third antennomere subequal to scape, about 1.3 to 1.8 longer than fourth, fifth antennomere about 1.4 longer than third, varying from slightly less than twice to three times the length of fourth, sixth subequal to seventh, eighth to tenth becoming progressively shorter, eleventh slightly longer than tenth; basal antennomeres subcylindrical, from antennomere 5 slightly flattened, with apices of antennomeres 5–10 produced externally (fifth only very slightly), more pronounced on antennomeres 7–10. Antennomeres feebly shining, scape moderately coarsely, moderately densely, shallowly punctate; clothed with fine, short, recumbent, pale pubescence with slightly longer, suberect hairs intermixed, sparser on basal segments, becoming denser on distal ones, antennomeres 2–6 ciliate beneath with coarse, moderately long, suberect, pale hairs. Pronotum about 1.3 longer than broad, widest at middle, slightly broader at base than apex, sides arcuately inflated, with a broad constriction at basal fifth, and a slight inflation just before apex; basal and apical margins slightly arcuate; disk slightly flattened medially, sometimes with three broad, rounded raised areas, one medial and two anterior to middle, one on each side. Surface moderately shining, often with fine wrinkles, sparse to moderately densely, shallowly, moderately coarse punctation on disk, laterally alutaceus with deeper punctures. Pronotum mostly glabrous except each side with two long, suberect setae, one anterolateral, the other one discal at basal third. Scutellum small, rounded, shining, impunctate. Elytra about 2.7 to 3 times as long as width at humeri, about 2.6 to 3 times as long as pronotal length, about 1.2 to 1.4 times broader basally than pronotom at widest (at middle); sides slightly sinuate, evenly rounded to apex which is rounded; epipleural margin sinuate. Disk slightly concave medially, subsuturally, creating a faint costa on each elytron. Surface shining; punctation moderately dense, coarse, punctures becoming finer towards apex and sides, almost obsolete at apical third; glabrous except for a few very fine, inconspicuous short hairs in punctures near apex. Underside with prosternum shining, rugose; apical fourth impunctate and one irregular patch of coarse punctures in front of each coxa ( Fig. 2e ); with very sparse, short, inconspicuous, pale hairs; narrowest area of prosternal process between coxae about 0.25 to 0.3 as wide as coxal cavity, and about 0.25 to 0.5 the width of apex of process which is subtriangular with rounded corners. Mesosternum shining; moderately finely to moderately coarsely punctate; with few short, inconspicuous pale hairs. Mesepisternum sparsely punctate; sparsely clothed with fine, short, pale hairs. Mesepimeron with denser pubescence. Metasternum shining; moderately finely to moderately coarsely, sparsely punctate; punctures with a fine, short, pale hair. Metepisternum moderately densely clothed with short, recumbent, pale pubescence, which is denser posteriorly. Abdomen shining; finely, shallowly punctate; abdomen with a few long, suberect pale hairs and punctures with a short, fine, pale hair; fifth sternite broadly rounded, slightly longer than preceding sternite. Legs with femora pedunculate­clavate, meso­ and metafemora arcuate, shining, finely,

shallowly punctate, clothed with sparsely to moderately densely, recumbent, short, pale pubescence; underside of each femoral club with a broad triangular tooth with posterior edge strongly serrate; tibiae slightly arcuate, sinuate; clothed with sparse to moderately dense, fine, recumbent, pale pubescence, becoming longer and coarser apically. Genitalia see Fig. 3b.

FEMALE. Length 5.0– 7.2 mm; width 1.2–1.7 mm (measured across humeri). Very similar to male. Antennae about as long as body. Lateral punctures on pronotum not distinctly deep and prosternum only finely punctate, lacking patches of coarse punctation ( Fig. 2f ). Narrowest area of prosternal process between coxae about 0.25 to 0.4 as wide as coxal cavity, and about 0.3 to 0.6 the width of apex of process.

Etymology. This species is named in memory of Dr. José A. Ramos for his invaluable contributions and his lifelong dedication to the study of insects in Puerto Rico, and for unconditional access to specimens from his remarkable personal collection, one of the largest on the Island.

Types. Holotype, male, PUERTO RICO, Maricao, Rd. 120, Km. 13.8, 26­IV­1980, J. & N. Micheli, coll., beating foliage ( USNM) . Allotype, female, PUERTO RICO, Maricao, Rd. 120, Km. 15.9, ex twigs Eugenia nr. ligustrina, coll. 17­X­1981, emerged XII­81, J. Micheli, coll. ( USNM) . Paratypes, 56: 1 female, same data as holotype ( JAMC) ; 1 male, PUERTO RICO, Maricao, Rd. 120, Km. 13.8, 3­V­1980, J. Micheli, coll., beating dead foliage ( JAMC) ; 1 male, same data as previous except, 10­V­1980 ( JAMC) ; 3 males, PUERTO RICO, Maricao, Rd. 120, Km. 15.9, ex twigs Eugenia nr. ligustrina, coll. 17­X­ 1981, emerged XI­81, J. Micheli, coll. ( JAMC, ENPC) ; 14 males and 2 females, same data as previous except, emerged XII­81 ( JAMC, USNM, ENPC; 2 dissected) ; 1 male and 1 female, same data as previous except, emerged II­82 ( JAMC) ; 4 males and 4 females, same data as previous except, emerged III­82 ( JAMC, ENPC; 1 dissected) ; 1 male, PUERTO RICO, Maricao, Rd. 120, Km. 15.9, 18­X­1981, beating foliage, J. Micheli, coll. ( JAMC) ; 1 male, PUERTO RICO, Maricao For., Water Filtration Plant , 18°09'N, 66°59’W, 17 June 2002, Turpenia paniculata, Steven W. Lingafelter ( USNM) ; 1 female, PUERTO RICO, Maricao, Bosque Estatal de Maricao, 3.3 km SW Maricao, 18­09­39N, 67­00­05W, forest, 550 m, 10­11 June 1996, J. Rawlins, C. Young, R. Davidson, W. Zanol, S. Thompson, M. Klingler ( CMNH) ; 1 female, PUERTO RICO, Hwy 120, km. 16.2, Hdqts. Maricao St. For. 8­8­1999, C. W. O’brien ( DHPC) ; 1 female, PUERTO RICO, Hwy. 120, K10H2, Maricao For. Res. , July 26, 1979, L.B. O'Brien ( JEWC) ; 1 male, PUERTO RICO, Guánica Forest , 6­IV­2001, ex dead log, Charyn J. Micheli, coll. ( JAMC) ; 1 female, PUERTO RICO, Guánica Forest, Ballena trail, beating, 17°58'49"N, 66°51'74"W, 16 June 2002, Steven W. Lingafelter ( USNM) ; 1 male, PUERTO RICO, Guánica Forest, Ballena trail, UV light, Spec ID:4228, Nearns & Lingafelter, 27­VII­2004 ( ENPC) ; 1 male, PUERTO RICO, Ponce, Rd. 132, Km. 20, 26­VI­1972, J. Micheli, coll., at lights ( JAMC) ; 2 males, PUERTO RICO, Ponce dry forest at Holiday Inn , 17°58'N, 66°38'W, 20 June 2002, beating, Steven W. Lingafelter ( USNM, ENPC; 1 dissected) ; 1 male, PUERTO RICO, Ponce dry forest behind Holiday Inn , 17°58'N, 66°38'W, 1 July 2002, Thouinia portoricensis, Steven W. Lingafelter ( USNM) ; 2 males and 2 females, PUERTO RICO, Guanica, Bosque Estatal de Guanica, 3.6 km E Guanica, 17­58­11N, 66­ 52­28W, thornscrub, 100 m, 12 June 1996, J. Rawlins, R. Davidson, C. Young, M. Klingler, W. Zanol, S. Thompson ( CMNH) ; 1 female, 17°56'50"N, 066°51'48"W, PUERTO RICO, Guanica, Bosque Estatal de Guanica, just W. Punta Ballena on Rt. 333, 9.VIII.1999, P. W. Kovarik, collector, beating ( WIBF) ; 1 female, PUERTO RICO, Humacao Dist., Casa Cabuy, Hwy. 191 nr. Florida , 31­VII–2­VIII­1999, J. E. Eger, MV & UV lights ( RFMC) ; 1 female, VIRGIN ISLANDS, St. John, Lameshur Bay – VIERS, 09 March 1984, at UV light, W. B. Muchmore colr. ( WIBF) ; 1 female, VIRGIN ISLANDS, St. John, Est. Caneel Bay, Lind Point , December 1992, J. Comisky colr. ( WIBF) ; 1 male and 1 female, VIRGIN ISLANDS, St. John, Lameshure Bay , VIERS, 21­28 July 1994, M. S. Becker colr, ultraviolet light ( WIBF) ; 2 males, BRITISH VIRGIN ISLANDS, Guana Island, Sugarloaf trail, 100­800 ft., 09 OCT 1994, M. A. & L. L. Ivie ( WIBF) .

Discussion. Throughout the series there is some variation in color and slight variation in the shape of pronotal margins, pronotal texture, punctation on pronotum and mesosternum, and proportion and shape of the prosternal process. Specimens collected in the wet forest of Maricao are quite dark and the pale maculae on the elytra tend to be rather compact ( Fig. 2d ). Those from the drier areas of Guánica and Ponce (in Puerto Rico) and the Virgin Islands are lighter colored with the pale areas on the elytra more like fasciae ( Fig. 2g ). Except for color, other variation is slight and there is much overlap. To further investigate the possibility of two distinct species, dissections of male genitalia of several specimens from each phenotype were made by the junior author. Detailed study of the tegmen including the parameres (lateral lobes) and phallobase (basal piece) revealed no consistent morphological characters ( Fig. 3b ). Since we can find no significant differences between specimens from “wet” and “dry” areas, only a single species will be proposed.

This species can be confused with Plectromerus serratus (Cameron) but can be distinguished by the punctation of the pronotum: in P. serratus , the pronotum is impunctate and dull, whereas P. ramosi has a shiny pronotum and distinct punctation. Also, the fifth antennomere in P. serratus ( Fig. 2i ) is distinctly pronounced externally at apex whereas in P. ramosi ( Fig. 2h ) it is only slightly expanded. Some small, light specimens of P. ramosi are similar to P. distinctus (Cameron) but the latter species has long, suberect hairs on the elytra and granulose punctures on the pronotum, both lacking in P. ramosi . From other congeners, P. ramosi can be distinguished by the following combination of characters: the shape and punctation of pronotum (widest at middle, shallow, moderately coarse punctures), the punctation and macular pattern of elytra, the glabrous pronotum and elytra, and the serrate metafemoral tooth.

Figures

FIGURE 2. a–c, Plectromerus lingafelteri Micheli & Nearns, new species: a, holotype; b, closeup of prosternum, male; c, closeup of prosternum, female; d–h Plectromerus ramosi Micheli & Nearns, new species: d, holotype; e, closeup of prosternum, male; f, closeup of prosternum, female; g, lighter phenotype; h, closeup of fifth antennomere; i, Plectromerus serratus (Cameron), closeup of fifth antennomere of holotype.

FIGURE 3. Tegmen and parameres, ventral view: a, Plectromerus lingafelteri Micheli & Nearns, new species; b, Plectromerus ramosi Micheli & Nearns, new species.