Hesperobaenus constricticollis, Bousquet, 2002

Schnepp, Kyle E., McElrath, Thomas C. & Powell, Gareth S., 2019, The beetle fauna associated with the peduncle of Sabal mexicana (Arecaceae) in southern Texas, Journal of Natural History 53 (35), pp. 2183-2193 : 2183-2193

Hesperobaenus constricticollis adult redescription (modified from Bousquet 2002)

Material examined. Holotype: not directly examined, but images of holotype examined from Quinn (2011). Non-type material: 14 females, 13 males examined ( GSPC, KESC) from the habitat as described above.

Redescription (including variation from new material examined). Body length: 2.6 mm (holotype) Colouration of head, pronotum and scutellum light red-brown, elytra paler-yellow (holotype, 5 specimens collected herein); or head, pronotum, scutellum with surrounding area, apical two-thirds of elytra, and pygidium dark brown, transversehourglass shape on basal one-third of elytra lighter orange (all other specimens collected herein, Figure 4 ). Prosternal apophysis without microsculpture.

Head. Wider than long (WH/LH: [not recorded on holotype]; avg. females = 1.51, range = 1.42 – 1.67; avg. males = 1.60, range = 1.54 – 1.72); wider than pronotum in males, narrower than pronotum in females (WH/WP: 1.09 [holotype]; avg. females = 0.97, range = 0.89 – - 0.99; avg. males = 1.05, range = 1.02 – 1.10). Eye rather large, longitudinal diameter about 1.5× length of antennomere 1. Temple moderately long, about 0.5× longitudinal diameter of eye, not produced posteriorly ( Figure 4 ). Antennomere 9 as wide as long, narrower than antennomere 10.

Thorax. Pronotum transverse-subquadrate (LP/WP = 0.88 [holotype]; avg. females = 0.94, range = 0.87 – 1.01; avg. males = 0.88, range = 0.82 – 0.92) with sides markedly narrowed in posterior half; anterior angle rounded, not produced ( Figure 4 ); punctures rather distantly spaced laterally, not subcontiguous; disc flat, with moderately wide, median impunctate area, widening in posterior half. Hypomeron rugose. Elytra moderately long (LE/LP = 1.84 [holotype]; avg. females = 1.82, range = 1.60 – 1.95; avg. males = 1.83, range = 1.71 – 1.95), without oblique impression on anterior third. Third and fifth intervals with 0 – 2 setigerous punctures at base; scutellum without setigerous punctures.

Abdomen. First visible sternite with coxal bead not triangularly produced but thickened, without longitudinal extension ( Figure 5 ). Male first abdominal sternite with small tuft of short (but longer than adjacent ones) setae at middle. Male last visible sternite without depression. Male genitalia as in Bousquet (2002, p. 206).

Diagnosis. Distinguished from other Hesperobaenus in North America north of Mexico by the markedly narrowed pronotum posteriorly.

Distribution. This species is known only from the type locality, but there are other specimens of Hesperobaenus from extreme South Florida, Central, and South America with superficially similar body shapes to this species (McElrath, pers. obs.).

Habitat. The species has only been collected directly from Texas sabal Palms in the manner described above.

Figures

Figure 4. Dorsal habitus micrographs of adult male Hesperobaenus constricticollis showing variation in adult colour pattern, pronotal and head width, and size.

Figure 5. Ventral habitus micrographs of adult male Hesperobaenus constricticollis showing variation in adult colour pattern, pronotal and head width, and size.