Plectromerus navassae Nearns & Steiner, 2006

Nearns, Eugenio H. & Steiner, Warren E., 2006, A new species of Plectromerus Haldeman (Coleoptera: Cerambycidae) from Navassa Island, Greater Antilles, Zootaxa 1163, pp. 61-68 : 63-67

Plectromerus navassae Nearns & Steiner , new species

Figs. 2a , d–g.

Description

MALE. Length 5.1–6.7 mm, width 1.2–1.6 mm (measured across humeri). Habitus as in Figure 2a . General form small, narrow, subcylindrical. Integument testaceous, with head, antennae, and basal fourth of elytra ferrugineus. Apical half of each elytron and visible abdominal segments distinctly darker, dark brown to black ( Fig. 2a, d ). Head with front nearly flat, transverse, with a median, shallow line from between eyes to just beyond vertex, slightly concave between antennal tubercles, which are somewhat raised and widely separated. Eyes coarsely faceted, transverse, subreniform. Antennae elevensegmented, slightly longer than body; scape bowed, third antennomere subequal to scape, only slightly longer than fourth, fifth antennomere longest, almost 2 times longer than fourth, antennomeres 6–11 becoming progressively shorter, sixth through eleventh slightly longer than third, basal antennomeres subcylindrical, from fifth slightly flattened, apices of antennomeres 6–10 produced externally. Scape with few long, suberect, pale hairs; antennomeres 2–7 ciliate beneath with coarse, moderately long, suberect, pale hairs. Pronotum subcylindrical, about 1.5 times as long as wide, widest at middle, slightly broader at apex than base, sides broadly inflated, arcuately constricted at basal third, and a slight inflation just before apex; basal margin slightly arcuate; disk convex, with scattered, long, suberect, pale hairs; each side of pronotum with coarse, deep punctures laterally and one or two long, suberect setae anterolaterally. Surface opaque, alveolate­punctate. Scutellum small, rounded, almost as long as broad, impunctate. Elytra about 2.75 times as long as width at humeri, about 2.3 times as long as pronotal length, about 1.3 times broader basally than pronotum at widest point (at middle); sides nearly parallel, slightly sinuate around middle, evenly rounded to apex which is very slightly subtruncate; epipleural margin moderately sinuate. Elytral disk slightly concave medially, subsuturally; base of each elytron slightly raised. Elytral surface shining; punctation moderately dense, coarse, and deep at basal third; punctures becoming finer towards apex and sides, almost obsolete at apical third; each puncture with a short, fine, pale hair; elytra with scattered, long, suberect, pale hairs. Underside with prosternum shining, one irregular patch of coarse, deep punctures in front of each coxa; narrowest area of prosternal process between coxae about 0.17 times as wide as coxal cavity, and about 0.5 times the width of apex of process which is subtriangular with rounded corners; coxal cavities open behind ( Fig. 2e ). Mesosternum surface shining, sparsely and finely punctate. Metasternum surface shining, sparsely and finely punctate, with moderately dense deeper punctures and suberect, pale hairs interspersed. Metepisternum sparsely clothed with short, recumbent, pale pubescence, which is denser posteriorly. Abdomen shining, dark brown to black in color; finely, shallowly punctate; abdomen with moderately dense long, suberect, pale hairs and punctures with a short, fine, pale hair; fifth sternite broadly subtruncate, slightly longer than preceding sternite. Legs with femora clavate, meso­ and metafemora slightly arcuate, shining, clothed with sparsely to moderately densely, recumbent, short, pale pubescence and with scattered, suberect, pale hairs arising from shallow punctures; underside of each femoral club with a broad triangular tooth with posterior edge moderately serrate, with about 12 serration “peaks”; tibiae slightly arcuate, sinuate though not strongly; clothed with moderately dense, fine, recumbent, pale pubescence, becoming longer and coarser apically ( Fig. 2g ).

FEMALE. Length 5.3–7.3 mm; width 1.3–1.7 mm (measured across humeri). Very similar to male except pronotal sides lacking coarse punctures and prosternum lacking irregular patch of punctures in front of each coxa ( Fig. 2f ). Abdomen with terminal sternite evenly, broadly rounded, about 1.5 times longer than preceding sternite.

Etymology

The Latin­like feminine proper name Navassa, combined with the genitive singular possessive ending “­ae” forms the specific name navassae , “of Navassa,” in reference to the type­locality and known distribution.

Types

Holotype, male ( Fig. 2a ), NAVASSA ISLAND, near lighthouse, 80 m., 18°23.82’N, 75°00.74’W, 3 August 1998, Collrs. W. E. Steiner, J. M. Swearingen, et al., at black light in open weedy scrub near mixed forest ( Ficus , Metopium , Thrinax ) on limestone and red oolitic soil (USNM) . Allotype, female, NAVASSA ISLAND, central forest area, 70 m., 18°24.08’N, 75°00.69’W, 28 July 1998, Collrs. W. E. Steiner, J. M. Swearingen, et al., at black light in gap of mixed forest ( Ficus , Metopium , Thrinax ) on limestone (USNM) . Paratypes, 15 (all from Navassa Island, collected by W. E. Steiner, J. M. Swearingen, et al. except as noted): 2 males, central forest area, 70 m., 18°23.99’N, 75°00.67’W, 26 July – 4 August 1998, Collrs. W. E. Steiner, J. M. Swearingen, et al., Malaise trap in gap of mixed forest ( Ficus , Metopium , Coccoloba , Sideroxylon , Thrinax ) on limestone (USNM) ; 1 male, central forest area, 70 m., 18°23.99’N, 75°00.67’W, 26 July – 4 August 1998, Collrs. W. E. Steiner, J. M. Swearingen, et al., Malaise trap in gap of mixed forest ( Ficus , Metopium , Coccoloba , Sideroxylon , Thrinax ) on limestone (UCRC) ; 1 female, same data as allotype (USNM) ; 1 male and 1 female, near lighthouse, 80 m., 18°23.82’N, 75°00.74’W, 24 July – 4 Aug. 1998, taken in Malaise trap, edge of open weedy scrub and mixed forest ( Ficus , Metopium , Thrinax ) on limestone (FSCA) ; 1 male (dissected), near lighthouse, 80 m., 18°23.82’N, 75°00.74’W, 26 July 1998, at black light in open weedy scrub near mixed forest ( Ficus , Metopium , Thrinax ) on limestone and red oolitic soil (E NPC) ; 1 female, near lighthouse, 80 m., 18°23.82’N, 75°00.74’W, 31 July 1998, at black light in open weedy scrub near mixed forest ( Ficus , Metopium , Thrinax ) on limestone and red oolitic soil (FTHC) ; 1 female, near lighthouse, 80 m., 18°23.82’N, 75°00.74’W, 2 August 1998, at black light in open weedy scrub near mixed forest ( Ficus , Metopium , Thrinax ) on limestone and red oolitic soil (CMNH) ; 1 male, E. end of east savanna, 65 m., 18°23.75’N, 75°00.52’W, 1 August 1998, at black light in open weedy scrub near mixed forest ( Ficus , Metopium , Thrinax ) on limestone and red oolitic soil (CMNH) ; 1 female, forest west of lighthouse, 75 m., 18°23.91’N, 75°00.81’W, 30 July – 4 Aug. 1998, Malaise trap in moist depression of mixed interior forest ( Ficus , Sideroxylon , Metopium , Coccoloba ) (EMEC) ; 2 females, forest west of lighthouse, 75 m., 18°23.91’N, 75°00.81’W, 30 July 1998, at black light in moist depression of mixed interior forest ( Ficus , Sideroxylon , Metopium , Coccoloba ) (AMNH, WIBF) ; 1 female, bluff of southwest rim, 65 m., 18°23.75’N, 75°00.94’W, 25–30 July 1998, Malaise trap in open mixed forest ( Ficus , Metopium , Coccoloba ) at rim of upper terrace on limestone and red oolitic soil (TAMU) ; 1 female, 7 May 1999, S. Navarro (USNM).

Discussion

We believe Plectromerus navassae to be endemic to Navassa Island and the type series described herein represents the only known specimens. This species is very distinctive from the known congeners and can be distinguished by the combination of the following characters: the alveolate­punctate pronotum, the presence of long, suberect hairs on elytra, apical half of elytra and abdominal segments dark brown or black, and moderately serrate metafemoral teeth.

Three other known species, Plectromerus distinctus (Cameron, 1910) ( Fig. 2b ), Plectromerus fasciatus (Gahan, 1895) , and Plectromerus wappesi Giesbert, 1985 ( Fig. 2c ) also possess long, suberect elytral hairs and serrate metafemoral teeth. From P. distinctus , the new species can easily be recognized by the alveolate­punctate pronotum (granulose punctures in P. distinctus ) and elytral coloration (elytra with small, ferrugineus fasciae in P. distinctus and P. fasciatus ). From P. wappesi , the new species can easily be recognized by elytral coloration (elytra with small, ferrugineus fasciae in P. wappesi ). The clavate metafemora and slightly sinuate metatibiae in P. navassae ( Fig. 2g ) are somewhat similar to P. distinctus ( Fig. 2h ) but differ significantly from P. wappesi which possess pedunculate­clavate metafemora and more strongly sinuate metatibiae ( Fig. 2i ).

Figures

FIGURE 2. a, Plectromerus navassae Nearns & Steiner, new species, holotype, male, dorsal habitus; b, Plectromerus distinctus (Cameron), holotype, female, dorsal habitus; c, Plectromerus wappesi Giesbert, paratype, male, dorsal habitus; d–g, Plectromerus navassae Nearns & Steiner, new species: d, holotype, male, lateral view; e, holotype, male, closeup of prosternum; f, allotype, female, closeup of prosternum; g, holotype, male, metafemur and metatibia, ventral view; h, Plectromerus distinctus (Cameron), holotype, female, metafemur and metatibia, ventral view; i, Plectromerus wappesi Giesbert, paratype, male, metafemur and metatibia, ventral view.