Crossidius grahami Morris and Wappes, 2013

Morris, Roy F., Ii & Wappes, James E., 2013, Description of a new Crossidius LeConte (Coleoptera: Cerambycidae: Cerambycinae: Trachyderini) from southern Georgia with comments on its biology and unusual distribution, Insecta Mundi 2013 (304), pp. 1-7 : 3-6

Crossidius grahami Morris and Wappes , new species

( Figures 1-3, 5, 9-10)

Description. Male ( Fig. 1): Moderate sized, elongate, parallel-sided, robust; integument entirely brownishtestaceous, pronotum with three dark-brown to black discal spots, elytra entirely testaceous. Head with pale pubescence, sparse, not obscuring surface, denser on front of head and along basal margin; underlying punctures dense, almost contiguous, smaller than those on elytra. Antennae 11 segmented, short, reaching apical quarter of elytra but not surpassing apices; scape twice as long as broad; third segment short, stout, as long as the scape and second segment combined, slightly expanded at apex ( Fig. 5); antennomeres 4-10 flattened with length subequal to scape; antennal punctures and pale pubescence sparse. Pronotum cylindrical, swollen, almost parallel sided, basally and apically margined; sides rounded, lacking tubercles; surface punctures dense, larger than those at base of elytra; pale pubescence moderate, not obscuring surface; discal area with two punctate, glabrous submedial dark areas and a less punctate similar area basally. Prosternum swollen at sides, densely pubescent across middle. Metasternum finely punctate, densely pubescent. Scutellum dark, flat, triangular, not indented medially, apex slightly rounded; pubescence fine. Elytra length 2.4 times width of both elytra at the humeri; surface moderately coarsely, densely punctate, becoming denser apically; pubescence short, pale, sparse, not obscuring surface; apices slightly rounded, angles usually distinct but not acute. Legs with fine punctures, pubescence sparse, not obscuring surface; mesotibial spurs short, nearly subequal in length. Abdomen with dense, pale pubescence, almost obscuring the fine surface punctures. Length 10-15 mm.

Female ( Fig 2): Form similar to male except as noted. Body testaceous with head, antennomeres, elytra and legs black, uniformly covered with short pale pubescence. Head punctate, sparsely pubescent. Antenna 11 segmented, reaching middle of elytra, sparsely pubescent, punctuate with puctures small and shallow. Pronotum not inflated (as in male); pubescence pale, sparse; punctures larger than those of elytral base. Elytra with apical third slightly expanded, pubescence short, sparse and erect. Legs short, with sparse pubescence. Abdomen and metasternum with fine, pale, suberect pubescence not obscuring surface. Length 12-15 mm.

Variation. Females from Tattnall County, GA tend to have the basal third of the elytra tan ( Fig. 3) while those from Emanuel County have solid black elytra ( Fig. 2).

Diagnosis. Crossidius grahami is the only Crossidius species known from east of the Mississippi River and to date has only been found in the relict sand formations of southern Georgia. As such its distribution is diagnostic. It is also morphologically unique for Crossidius species in having the antenna distinctly shorter than the elytra in both sexes. From its nearest geographical relative, C. humeralis quadrivittata Penrose ( Fig. 4), C. grahami can be separated by the following characters: shorter, more robust and apically expanded antennomeres ( Fig. 5); shorter, nearly subequal metatibial spurs; greatly reduced pubescence on the sides of the pronotum, and on the vertex of the head and between the eyes; and by the lack of elytral vitta. In C. h. quadrivittata, antennomeres are longer and nearly parallel-sided ( Fig. 6); inner metatibial spur distinctly longer than outer; long, dense pubescence on the sides of the pronotum, and on the vertex and between the eyes, and distinct, dark elytral vitta in most specimens.

Type Material. Male holotype of Crossidius grahami labeled: “/ GA: Emanuel co., 1.5 mi. S. Covena, 10/VI/00, R. Morris / Sweeping Chrysoma plauciflosculosa /”. The female allotype is labeled: “/ GA: Emanuel co., 1.5 mi. s. Covena, 6/VI/99, R. Morris/”. They are deposited in the FSCA.

Paratypes: 257 males and 84 females ( Unless otherwise noted the following paratypes are deposited in the collection of the collector). Georgia: Same data as holotype (13m, 6f – RFMC, 4m, 2f - UGAC; 1m – RMBC) ; Emanuel Co.: 1.5 mi. S. Covena, 6/VI/99, R. Morris (9m, 1f – RFMC; 1f – RMBC) ; 1 mi. SW Covena , 11 June 2000, R. Turnbow, on Chrysoma pauciflosculosa (Michx.) Greene (6m, 2f-USNM) ; 1 mi. SW Covena , 10 June 2000, R. Turnbow, on Chrysoma pauciflosculosa (Michx.) Greene (17m, 9f - RHTC) ; 1 mi. SW Covena , 11 June 2006, R. Turnbow, on Chrysoma pauciflosculosa (Michx.) Greene (17m, 5f - RHTC) ; 1 mi. SW Covena , 11 June 2011, R. Turnbow, on Chrysoma pauciflosculosa (Michx.) Greene (20m, 9f – RHTC, 4m, 2f EMEC) ; Ohoopee Dunes WMA, Co. Rd. 160, 12/VI/1999, R. Morris, sweeping Chrysoma pauciflosculosa (6m – RFMC) ; Ohoopee Dunes Natural Area , Hall’s Bridge Rd., 10/VI/00, R. Morris, sweeping Chrysoma pauciflosculosa (7m, 1f – RFMC) ; Ohoopee Dunes Natural Area , 10 June 2000, R. Turnbow, on Chrysoma pauciflosculosa (Michx.) Greene (5m, 2f – MNRJ, 5m 2f - MZSP) ; Ohoopee Dunes Natural Area , 11 June 2011, R. Turnbow (2m - RHTC) ; Ohoopee Dunes Natural Area , 12 June 2011, R. Turnbow (2m, 1f - RHTC) ; Ohoopee Dunes Natural Area , 4.5 km NE Norristown, Halls Bridge Tract, 32.53581, -82.46023, 8 June 2011, beaten from foliage of woody goldenrod, Chrysoma pauciflosculosa, R. A. Androw , coll. (3m - RAAC) ; Ohoopee Dunes Natural Area , 32 o 32’15”N 82 o 27’40”W, 19 June 2002, T. L. Schiefer, R. L. Brown, or J.G. Hill, sweeping Chrysoma pauciflosculosa in xeric dune scrub. W. H. Cross Expedition (9m, 1f – MEMC) ; Hwy. 56 at Ohoopee River, 10 June 2000, R. Turnbow (1m – RHTC) ; I-16 & US 1, Gar Rd. , 6-7/VI/99, R. Morris (18m, 4f – RFMC) ; I-16 & US 1, Gar Rd. , 12/VI/ 99, R. Morris, sweeping Chrysoma pauciflosculosa (5m – RFMC) ; I-16 & US 1, Gar Rd. , 9/VI/00, R. Morris, sweeping Chrysoma pauciflosculosa (1m – RFMC) ; I-16 & US 1, Gar Rd. , 15/VI/01, R. Morris (1m – RFMC) ; I-16 & US 1, Gar Rd. , 30/V/10, J. Basham, cut fm Chrysoma pauciflosculosa root crown 14/I/10 (1f – JPBC) ; Jct. Rts. 1 & 16, VI/15-16/03, J. &M. Huether (8m, 2f – JHGC) ; Jct. I-16 & hwy. 1, 9 June 2000, R. Turnbow, on Chrysoma pauciflosculosa (Michx.) Greene (9m, 1f – RHTC) ; Tattnall Co.: 3 mi. E of 147 along Ohoopee River , Col. 1-IV-98, Em. 1-VI-98, R. Morris, ex Chrysoma pauciflosculosa (1m – RFMC) ; 3 mi. E of 147 along Ohoopee River , 12-13-VI-1998, R. & G. Morris, sweeping Chrysoma pauciflosculosa (18m, 5f – RFMC) ; 3 mi. E of 147 along Ohoopee River , 12-VI-1998, Roy & Graham Morris (1m – RFMC) ; 3 mi. E of 147 along Ohoopee River , 20-VI-1998, Morris / Wappes, sweeping Chrysoma pauciflosculosa (5m, 1f – RFMC) ; 3 mi. E of 147 along Ohoopee River , 19-20 June 1998, Wappes & Morris, sweeping woody goldenrod, Chrysoma pauciflosculosa Grn. (5m, 3f -ACMT) ; 2 mi. E of 147 along Ohoopee River , 11/VI/99, R. Morris, sweeping Chrysoma pauciflosculosa (1f – RFMC) ; 2 mi. E of 147 along Ohoopee River , 30-V-04, Morris / Nearns / Skelley (6m – RFMC) ; 2 mi. E of 147 along Ohoopee River , 5-VI-99, R.Morris (5m, 4f – RFMC) ; 2 mi. E of 147 along Ohoopee River , 5-VI-99, J. Burne (6m, 2f – JBMC) ; 2 mi. E of 147 along Ohoopee River , 9-VI-99, J. Burne (15m, 4f – JBMC) ; 2 mi. E of 147 along Ohoopee River , 12-VI-99, J. Burne (9m, 1f – JBMC) ; 2 mi. E of 147 along Ohoopee River , 24-VI-99, J. Burne (3m, 3f – FSCA) ; 3 mi. S. of Reidsville , 22/VI/02, R. Morris (4m, 2 f – RFMC) ; 4 mi. S. Reidsville, 28 June , 1998, R. Turnbow, on Chrysoma pauciflosculosa (Michx.) Greene (3m - RHTC) ; 4 mi. S. Reidsville, 13 June , 2011, R. Turnbow, on Chrysoma pauciflosculosa (Michx.) Greene (8m, 2f- FSCA) ; 4 mi. S. Reidsville , 12-VI-2011, M. C. Thomas, sweeping Chrysoma pauciflosculosa (2m, 2f-FSCA) ; 1 mi. S. Covina , 11-VI-2011, M. C. Thomas, sweeping Chrysoma pauciflosculosa (3m, 2f-FSCA) .

Etymology. It is our pleasure to name this new species for Graham Morris, who as an eight year old accompanied his father to southern Georgia and helped collect the first specimens of this new species.

Biology. The known distribution of Crossidius grahami is restricted to the relict island sand dune systems along the Ohoopee and Little Ohoopee rivers in Emanuel and Tattnall counties of Georgia. These dunes were formed during the late Pliestocene glacial or the intermediate post glacial period ( Markewich and Markewich 1994), with the natural vegetation ( Fig. 7) upland scrub with smaller areas of dwarf oak forests ( Wharton 1978). The only known host plant of C. grahami is woody goldenrod, Chrysoma pauciflosculosa (Michx.) Greene (Asteraceae) ( Fig. 8). During April, 1998 the senior author found a dying woody goldenrod, 3 miles east of GA Highway 147, along the Ohoopee River. Curious about the cause of the plant’s demise he excavated and examined the root crown. After finding some larval working he cut it open and found the larvae of a cerambycid. Securing the pieces together it was placed in a rearing container on his desk at home. On June 1, a male of an unknown cerambycid emerged. Not knowing the identity of this specimen, a trip with his son Graham was made to the area the next week to look for more specimens. There, they successfully collected additional specimens by sweeping Chrysoma . Recently (January, 2012), Joshua Basham, McMinnville, TN, also confirmed woody goldenrod as a host plant by extracting a teneral male from its root crown pupal chamber ( Fig. 9). Most of the paratypical specimens have been collected by sweeping woody goldenrod or by handpicking, as they sit facing upward on the main stem ( Fig. 10). Only rarely have they been observed and taken in flight. Woody goldenrod occurs primarily in costal dunes, and among scrub oak ridges across the southern US, from Mississippi to the inner coastal plain of southern Georgia and all the way into North Carolina wherever suitable habitat is found (Godfrey 1988). Extensive collecting by the senior author in other areas of Georgia and north Florida, where the host plant occurs, has not yielded any specimens of C. grahami . We can only hypothesize that some biological factor, other than just having available host plant, is key to the species development and hence restricting its distribution.

Most Crossidius host plants bloom in the late summer and early fall, with adults of Crossidius species typically emerging at the start of the host blooming season. During the day both sexes can be found feeding on blossoms. Males also commonly perch with antenna extended, on the tallest flowers of the host, hoping to locate freshly emerged females. During cool or overcast days adults of both sexes can be found sitting quietly among the foliage and stems of the host plant waiting for warmer temperatures to then become active. It is assumed that most adults spend the night at the base of the host as we have observed adults crawling down the stems in the evenings and, as morning sun warms the air, crawling back up the plant and becoming active by mid-morning. Rarely, but especially on warm nights, adults of some smaller species can be found still flower sitting or in the upper foliage of the host. In one case we observed males of C. pulchellus LeConte , in West Texas, sitting on Gutierrezia flowers early in the morning covered by snow from a previous night’s snowfall. Chrysoma pauciflosculosa blooms in late October, somewhat later than western Crossidius hosts. Unlike the western species, adults of Crossidius grahami are normally late spring active with almost all collected specimens taken in late May or June. Obviously, this is not when the host, woody goldenrod, blooms. Hence, adults are not flower feeders and are not feeding at the top of the plant, exposed, to be easily found by the collector or observer. Rather, they sit on the main stem of the host ( Fig. 10), or hide in the dead leaves that are still attached to the terminal stem. This makes them much more difficult to find and experience indicates they are best collected by sweeping the plant. Collecting, during the fall bloom season, at localities known to have populations of C. grahami , has not produced any specimens. This aberrant behavior may help explain why the species has escaped discovery until recent years.