Chaetophloeus flourensiae Atkinson, 2024

Atkinson, Thomas H., 2024, New species, new synonymy, taxonomic notes and new records of bark and ambrosia beetles from the southwestern United States and northern Mexico (Coleoptera: Curculionidae: Platypodinae and Scolytinae), Zootaxa 5424 (2), pp. 151-175 : 152-156

Chaetophloeus flourensiae Atkinson , sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:AC5DC952-4D79-4D67-8C4E-85306143F92A

Fig. 1 (A–H), Fig. 2A

Diagnosis. This species is very similar in appearance to Chaetophloeus heterodoxus (Casey) ( Fig. 3 ) but differs in the arrangement and color of the abundant vestiture: white and light brown for C. flourensiae and beige and dark brown for C. heterodoxus . Chaetophloeus flourensiae breeds in composite shrubs in the Chihuahuan Desert of Arizona and western Texas (and probably northern Mexico) while C. heterodoxus breeds in a variety of hosts in the Rosaceae in foothill and montane woodlands from Arizona and New Mexico to Manitoba. It also resembles Chaetophloeus sulcatus Wood ( Fig. 4 ), but does not share the sulcate declivity of that species.

Male. Length pronotum: 0.53 mm; length elytra: 1.10 mm; total length: 1.62 mm; maximum width: 0.85 mm; length / width: 1.91 (n=5). Body entirely covered by dense, recumbent setae, rounded on dorsal surfaces, bifid or trifid on ventral and lateral surfaces. Overall color of scales a combination of white and pale, reddish brown.

Frons concave to upper level of eyes; surface shining, finely punctured, with some granules present at upper level of eyes. Vestiture of fimbriate setae abundant on sides and upper portion of frons, sparse in middle; longest and densest between mandibles and upper level of eyes. Epistomal margin concave, with highest point in center; dense fimbriate setae along anterior edge, longest laterally. Antennal scape club-shaped, subequal in length to combined pedicel and flagellum; pedicel about ¼ length of scape; flagellum with five segments. Antennal club narrow, flattened, elongate about length of combined scape and pedicel; four evenly spaced horizontal sutures marked by rows of setae visible.

Pronotum wider than long, widest anterior to base. Anterior margin smooth; several chisel-like asperities in a distinct clump present on antero-lateral surface on either side. Posterior ¼ of declivity at base with predominantly brown setae; anterior areas with a combination of light and dark scales, not forming a clear pattern.

Base of elytra with strongly elevated, chisel-like elevations (crenulations) on interstriae 1–6, highest and widest on interstria 1, diminishing in size laterally; all approximately in a straight line. Scutellum not visible. No submarginal elevations noted; large, wide, erect scales in confused region immediately behind crenulations on interstriae 1–3. Striae moderately impressed on disc, less so on declivity. Interstriae 3 × width of striae, covered with dense, confused, recumbent scales; some erect scales present posteriorly; granules not evident. Light and dark scales mixed in blotchy, variable pattern, not suggesting longitudinal lines or any other pattern. Declivity flat to rounded, interstria 1 weakly impressed; interstrial granules absent.

Venter of abdomen with white, bifid setae. Face of ventrite 5 with a weak longitudinal impression, vestiture similar to that of other segments.

Female. Length pronotum: 0.52 mm; length elytra: 1.10 mm; total length: 1.61 mm; maximum width: 0.83 mm; length / width: 1.94 (n=5). Similar to male except as noted below.

Frons flattened to shallowly concave in central area; dense fimbriate vestiture covering entire frons; epistomal margin nearly straight, not concave. Antero-lateral asperities on pronotum larger and more numerous that those of male. Abdominal ventrite 5 lacking longitudinal impression.

Type Material. Holotype male: United States: Texas: Jeff Davis Co., Springhills, I-10 exit 184, 31.8228 N, 104.1025 W, 1,238 m, 18-III-2016, ex Flourensia cernua, T.H. Atkinson (USNMENT01547792); allotype, same data but (USNMENT01547793); paratypes: same data ( CNIN, 1; TAMU, 1; USNM, 6; UTIC, 1); Arizona: Cochise Co., Middlemarch Rd., W of Pierce, 31.9053 N, 109.9930 W, 1,340 m, 25-XI-2015, ex Flourensia cernua, T.H. Atkinson ( USNM, 2; UTIC, 4); Cochise Co., St. David, E of, 31.9321 N, 110.1808 W, 1,186 m, 25-XI-2015, ex Flourensia cernua, T.H. Atkinson ( UTIC, 1); Texas: Brewster Co.: Glass Mountains, roadsite park on US Hwy 385, [30.4353 N, 103.1086 W], 26-III-2001, ex Flourensia cernua, T.H. Atkinson ( TAMU, 2); Culberson Co.: Hwy 62/180, 4 mi W jct Hwy 54, [31.7727 N, 104.8969 W], 20-VII-1989, Robbins, T. (USNMENT01358929, 1); Van Horn, 31.0612 N, 104.9679 W, 1,426 m, 1-X-2014, ex Flourensia cernua, T.H. Atkinson ( UTIC, 4); Hudspeth Co., Sierra Blanca, 31.1706 N, 105.3507 W, 16-VIII-2006, ex Flourensia cernua, T.H. Atkinson ( TAMU, 4).

Etymology. This species is named for its host, Flourencia cernua ( Asteraceae ), a shrub found primarily in the Chihuahuan Desert.

Biology and Distribution. All specimens were collected in this region in southern Arizona and western Texas. It is to be expected that this species will be collected in New Mexico and the Mexican states of Chihuahua and Coahuila, and possibly further south.

Breeding galleries are found in dead branches within the “mounds” of living hosts. This probably provides some shade to infested branches to partially ameliorate the extreme heat. On several occasions I examined branches of shrubs where the entire plant had been killed, usually by some mechanical injury. None of these had galleries. This was at sites where live beetles were collected.

The gallery is typical for other species in the genus. Galleries are initiated by females.A large, irregular, roughly circular chamber is excavated that is much larger than the diameter of a beetle and apparently allows both individuals to move freely. Several short egg galleries are excavated off this central chamber. Eggs are packed very tightly along these short galleries and larval mines radiate outwards. New adults emerge from individual exit holes.

Comments. This is most likely the species cited as Chaetophloeus heterodoxus (Casey) from Flourensia cernua by Richeson & Boldt (1995). They stated that voucher specimens were deposited in the USNM. The only specimen from Texas in in that collection is of this species and bears a Wood determination label. This is also likely the basis for including C. heterodoxus in Texas (locality not specified, Wood 1982). This species was reported erroneously as C. sulcatus by Atkinson & Riley (2013).

Figures

FIGURE 1. Chaeotophloeus flourensiae. Male holotype (USNMENT01547792): (A) Dorsal, (B) Lateral, (C) Frontal, (D) Posterior.Female allotype (USNMENT01547793):(E) Dorsal, (F) Lateral, (G) Frontal, (H) Posterior. Specimen data:Texas: Jeff Davis Co., Springhills, I-10 exit 184, 31.8228 N, 104.1025 W, 1,238 m, 18-III-2016, T.H. Atkinson (USNM). All photographs by the author.

FIGURE 2. Distribution maps. Newly reported records are represented by stars, previously reported records by solid circles. (A) Chaetophloeus flourensiae, (B) Chaetophloeus heterodoxus, (C) Chaetophloeus sulcatus, (D) Chramesus mimosa, (E) Phloeotribus scabricollis, (F) Pseudothysanoes yucce.

FIGURE 3. Chaeotophloeus heterodoxus. Male: (A) Dorsal, (B) Lateral, (C) Frontal, (D) Posterior. Female: (E) Dorsal, (F) Lateral, (G) Frontal, (H) Posterior. Specimen data: Mexico: Baja California, Col. Lázaro Cárdenas, 10 km W, 31.3573 N, 115.8275 W, 846 m, 11-XI-2105, ex Prunus ilicifolia, T.H. Atkinson (UTIC). All photographs by the author.

FIGURE 4. Chaeotophloeus sulcatus. Male holotype: (A) Dorsal, (B) Lateral, (C) Frontal, (D) Posterior. Female holotype: (E) Dorsal, (F) Lateral, (G) Frontal, (H) Posterior. Specimen Data: (A–D) Mexico: Hidalgo, Ixmiquilpan, [20.4830 N, 99.2330 W], 1,615 m, 23-VI-1953, S.L. Wood (SEMC); (E–H) Mexico: Coahuila: Saltillo, 25.3451 N, 101.0289 W, 17-V-2015, ex Gochnatia hypoleuca, T.H. Atkinson (UTIC). All photographs by the author.