Eubulus bisignatus (Say)

Anderson, Robert S., 2008, A Review Of The Genus Eubulus Kirsch 1869 In The United States And Canada (Curculionidae: Cryptorhynchinae), The Coleopterists Bulletin 62 (2), pp. 287-296 : 293-294

Eubulus bisignatus (Say)

( Figures 3–4 , 9–10 , 16 )

Cryptorhynchus bisignatus Say 1831:19 .

Eubulus bisignatus ; Champion 1905:581–582.

Cryptorhynchus v. tessellatus Blatchley 1916:509 .

Taxonomic notes. The holotype of Cryptorhynchus bisignatus Say is lost. In the interests of nomenclatural stability and the history of misidentifications of this species and others closely related to it, a neotype is here designated from the LeConte Collection (MCZC). It is generally regarded that LeConte had an opportunity to compare his specimens with those of Say before the latter were lost. The specimen is a male (not dissected) with a pink circle (5 Vermont, New Hampshire, Massachusetts), a handwritten label ‘‘ C. bisignatus Say / luctuosus Boh. / misellus Boh. ’’, my determination label and a red neotype label. Two other specimens are in the LeConte Collection, one with a pink circle and one with an orange circle. There are 3 specimens labeled ‘‘Can’’ in the Horn Collection. Blatchley (1916) described a variation ‘‘ tessellatus ’’ from Dunedin, Florida in which the form is more slender and the scales form a pattern of numerous zigzag lines across the elytra and the pale elytral spot is smaller. This name has no formal nomenclatural standing and no specimens were examined. Male genitalia dissected from specimens throughout the species range (including Arizona and California) show no significant variation.

LeConte (1876; 251) incorrectly placed C. luctuosus Boheman and C. misellus Boheman as junior synonynms of E. bisignatus . The former is now regarded as a junior synonym of E. parochus (Champion 1905; 581; O’Brien and Wibmer 1982:156) and the latter as a distinct Brazilian species of Eubulus (Champion 1905:581; Wibmer and O’Brien 1986; 242). Types of these species were not examined.

Diagnosis. Body size 2.8–4.9 mm ( Figs. 3–4 ). Head with eyes separated by twothirds to almost width of base of rostrum in frontal view; area above each eye lacking oblique subcarinate ridge or with ridge very poorly developed; frons not foveate; femora each with two very small indistinct teeth on inner margin. Males with first ventrite longitudinally concave medially, last ventrite of both sexes with uniformly appressed, broad scales, scales lighter in color laterally on ventrites 3–5; aedeagus ( Fig. 10 ) subparallel throughout basal half of length, internal sac with no obvious denticles; tergite VIII ( Fig. 9 ) of female broadly rounded, apical margin finely dentate.

Biology. This species is most frequently collected at lights and in malaise and flight intercept traps. Adults have been collected on oak, chestnut, beech and birch (Blatchley and Leng 1916), and museum specimens have been collected on hickory, oak and maple.

Distribution. Figure 16 . This species is widely distributed in the eastern United States and southern Canada, west in the south to Texas then apparently disjunct to Arizona and California. State records are AL, AZ, AR, CA, CT, DE, FL, GA, IL, IN, IO, KS, LA, MD, MA, MI, MS, MO, NE, NH, NJ, NY, NC, OH, PA, TN, TX, VA and WV; provincial records are ON and PQ.

Eubulus obliquefasciatus (Boheman) , resurrected name ( Figures 5–6 , 11–13 , 15 ) Cryptorhynchus obliquefasciatus Boheman 1844:349 .

Taxonomic notes. The holotype of Cryptorhynchus obliquefasciatus Boheman described from North Carolina has been examined (SMNH). It is a male with the diagnostic features and characteristic ventrite 5 of the other species that was mixed with E. bisignatus throughout most of the species range. LeConte (1876:251) and subsequent authors have incorrectly considered it a junior synonym of E. bisignatus (Say) . Blatchley and Leng (1916; following the exact wording of LeConte 1876:251) considered it a color variety of E. bisignatus in which the oblique white spot of the elytra extends from the second to the seventh stria and the scattered white dots are more conspicuous.

Diagnosis. Body size 2.8–3.5 mm ( Figs. 5–6 ). Head with eyes separated by half width of base of rostrum in frontal view; area above each eye lacking oblique subcarinate ridge; frons not foveate; front and middle femora each lacking teeth on inner margin; hind femur with inner margin with single small tooth. Males with first ventrite uniformly convex, ventrite 5 ( Fig. 11 ) with fine, golden, bifid scales each directed towards middle of posterior margin; females with all ventrites with broad appressed scales uniform in form and color; aedeagus ( Fig. 13 ) constricted near base, internal sac with dentate longitudinal fold throughout length; tergite VIII ( Fig. 12 ) of female narrowed, apical margin with 4 large denticles.

Biology. Specimens have been collected commonly in flight intercept traps and at lights. A few museum specimens were collected on dead oak and dead sweetgum. There are no other details on natural history.

Distribution. Figure 15 . This species is found across the middle-eastern to southeastern United States. State records are AL, AR, FL, GA, KS, KY, LA, MD, MA, MI, MS, MO, NJ, NY, NC, OH, OK, PA, SC, TN, TX, VA and WV. Despite its occurrence in bordering states, there are no Canadian records.

Specimens not assigned to species

Eubulus is a huge Neotropical genus and three individual specimens seen by me and collected in North America are not assignable to species. It is not known if the species are established in North America and in one instance the specimen may have been mislabeled.

TEXAS: Cameron County, Sabal Palm Grove , 13–14.XI.1988, R. S. Anderson ( CMNC). This individual has numerous erect seta-like scales dorsally, the front femur has a well-defined sharp tooth and aside from the typical oblique white elytral patch of scales, there is a tuft of black erect scales on interval 3 at the basal third. This species appears close to E. biplagiatus Champion .

FLORIDA: Highlands County, Lake Placid , 24.IX.2000, C.W. O’Brien and G.B. Marshall, at light ( CWOB). As with the specimen from Texas, this specimen has numerous erect (but finer) seta-like scales dorsally. Unlike other North American species there is no oblique white scale patch but rather the elytral pattern is lineolate with dense white scales along the lengths of intervals 4 and 8 and in the posterior half of intervals 2 and 3. The legs are longer and more slender and the front femur has a well-defined sharp tooth. No similar species from the Neotropical region are known to me .

MISSOURI: Boone County, Archibold Wildlife Area, 6.VI.1979, E.G. Riley, at UV light (CWOB). This species is easily recognizable by the scutellum with dense white scales (glabrous in other North American species) and with elytral intervals 3 and 5 low and rounded, not sharply carinate. There are no white elytral scales but a transverse patch of black velvety scales at the posterior third of the elytral length across the declivity. There is a poorly defined supra-ocular carina and intervals 7 and 9 of the elytra are carinate so the species may have been placed in Eubulus ; however, it bears a great resemblance to specimens identified as Cryptorhynchus quadrisignatus (Champion) from the Yucatan Peninsula of Mexico (CMNC). This specimen might have been mislabeled.

Figures

Figs. 1–6. Dorsal and lateral habitus of Eubulus species. 1, 2) Eubulus parochus; 3, 4) Eubulus bisignatus; 5, 6) Eubulus obliquefasciatus. Scale bar 5 1 mm.

Figs. 7–13. 7) Tergite VIII of female E. parochus. Scale bar 5 0.2 mm; 8) Aedeagus of male E. parochus. Scale bar 5 0.5 mm; 9) Tergite VIII of female E. bisignatus. Scale bar 5 0.1 mm; 10) Aedeagus of male E. bisignatus. Scale bar 5 0.5 mm; 11) Ventrite 5 of male E. obliquefasciatus. Scale bar 5 0.25 mm; 12) Tergite VIII of female E. obliquefasciatus. Scale bar 5 0.1 mm; 13) Aedeagus of male E. obliquefasciatus. Scale bar 5 0.25 mm.

Figs. 14–16. Maps of distribution of Eubulus species by state and province. 14) E. parochus; 15) E. obliquefasciatus; 16) E. bisignatus.