Epibrithus pustulatus Marshall, 1955

Hansen, Steffan P. & Haran, Julien M., 2025, Revision of the South African genus Epibrithus Marshall (Curculionidae, Entiminae) with description of two new species, European Journal of Taxonomy 1012, pp. 201-221 : 206-209

Epibrithus pustulatus Marshall, 1955

Figs 1 , 4–5

Epibrithus pustulatus Marshall, 1955: 7–8 (description, distribution).

Epibrithus pustulatus – Alonso-Zarazaga & Lyal 1999: 156 (catalogue).

Diagnosis

A morphologically variable species, even within populations. Can be distinguished from E. longicarinatus sp. nov. and E. boroveci sp. nov. by the cavity in ventrite 5 of male specimens that are covered across its area by scales ( Fig. 1E ). The penis is shorter than in E. longicarinatus and E. boroveci ( Fig. 1C ) with an abrupt taper in apical ⅓ (tapering regularly in E. longicarinatus and E. boroveci ). Females of this species can be distinguished from those of E. longicarinatus by their generally slightly smaller size and the more rounded elytra in lateral view (which reach their highest point in the middle vs elytra in E. pustulatus , with the highest point being situated more posteriorly vs close to the elytral declivity in E. longicarinatus ). It is the only species of Epibrithus amongst material examined where some specimens have a distinct darker ovate band on the elytra, rather than a more homogeneous grey vestiture ( Fig. 1A ).

Etymology

The species was probably named after the callosities (‘pustules’, Marshall, 1955) present on the interstriae on the elytra of adults.

Material examined

Holotype

REPUBLIC OF SOUTH AFRICA – Western Cape Province • ♂; “ Olifants River bet; Citrusdal & Clanwilliam C.P. ” “ Epibrithus pustulatus TYPE ♂ ” “ HOLOTYPE ” “Type SAM/Ent 4179” “IMAGED LEICA LAS 4.9 SAMC 2024 ”; SAMC.

Paratypes

REPUBLIC OF SOUTH AFRICA – Western Cape Province • 4 ♂♂, 4 ♀♀; same collection data as for holotype; type SAM/Ent 4180; SAMC • 3 ♂♂, 3 ♀♀; same collection data as for holotype; NHMUK .

Other material examined

REPUBLIC OF SOUTH AFRICA – Western Cape Province • 5 ♂♂, 1 ♀ (1 specimen preserved in ethanol); The Baths ; 32°44′31″ S, 19°02′6″ E; 3 Nov. 2019; J. Haran coll.; beating vegetation; JHAR03020 ; CBGP • 1 ♀, Olifants River Mountains ; O. Bokkeveld leg.; SAM-COL-A045235 , SAMC .

Redescription ( ♂ ♀)

BODY LENGTH. 6.6–9.1 mm.

COLOUR AND VESTITURE. Body integument dark red to black; elytral vestiture forming a dense cover of small, round to elliptical (slightly longer than wide) appressed brown-to-light grey scales, not completely covering the integument; callosities on elytra with tufts of suberect elongate scales, generally darker than surrounding vestiture; each elytron with an oblique dark band from humeral angle to apical ⅔ of suture in approximately 10–100% of specimens, depending on population; base of interstriae 1 with scale cover less dense, revealing integument.

HEAD. Rostrum longer than wide (w/l ratio: ♂ 0.84–0.86; ♀ 0.89), in dorsal view sides wider at antennal insertions than at the base (1.12–1.24 × ♂; 1.27 × ♀); apical to middle dorsal edges of pterygia raised abruptly above the level of frons in some specimens, causing pterygial edges to appear ridge-like; frons with scattered scales in basal part, epistome bearing 1 pair of setae (lacking setae in single specimens). Forehead with a distinct median fovea between eyes, distance between dorsal posterior margin of eyes> than width of eye; eyes moderately conveX. Scape 0.73–0.82 × as long as funicle, slightly curved to nearly straight; funicle with segments 1–2 elongate, longer than wide (w/l ratio 1: 0.35–0.48; w/l ratio 2: 0.46–0.58), 1 subequal to longer (1.14–1.36 ×) than 2, segments 3–6 subequal in length, 7 subequal in length to slightly longer than 6, longer than wide (w/l ratio 3: 0.70–0.91), conical; club spindle-shaped, segment 1 longer than 2, margins slightly sinuous.

PROTHORAX. Slightly wider than long (w/l ratio: ♂ 1.18–1.25, ♀ 1.32) in dorsal view, apical margin 0.83–0.87 × as wide as at base, sides moderately conveX, in lateral view highest point at the middle of length; median line with a groove not reaching base and apex of pronotum.

ELYTRA. Sides sub-parallel in the middle (w/l ratio: 0.67–0.73), apex broadly rounded; humeral angles located at 0.16–0.19 of elytral length; in lateral view, dorsal line conveX, reaches highest point in basal ⅓. Size of elytral callosities differs between populations.

LEGS. Tibiae nearly straight, internal margin often with row of 3–4 black, suberect spines; mucro concealed in a tuft of elongate curved golden-brown setae, distinctly longer and black on metatibiae in male.

ABDOMEN. Ventrites with pearly white rounded scales, contiguous but not concealing the integument; ventrite 1 intercoXal process slightly wider than the metaXocal width ( ♂ 1.67–1.75×; ♀ 1.81×), apical edge slightly bilobate in middle; in male ventrites 2 + 3 + 4 apical edges almost straight in middle; ventrite 5 ( ♂ 0.66–0.70 ×; ♀ 0.77 ×) as long as 2+ 3 +4, ventrite 5 wide (ratio w/l: ♂ 1.64–1.78; ♀ 1.44), male with a shallow cavity in apical ⅔ of length, bearing an indistinct short apical median carina shorter than ¼ the length of cavity, margin slightly bilobate, vestiture of ventrite 5 with a homogeneous cover scales, revealing integument but covering the bottom of cavity, apex with two short brush of black setae ( Fig. 1E ).

MALE TERMINALIA. Body of penis short ( 1.58–1.65 mm), elongate (w/l ratio: 0.33–0.37), widest in basal ⅔, sides of basal ⅔ subparallel in dorsal view, converging abruptly at apical ⅓, then regularly apicad, apeX acuminate, in lateral view downwards curvature strongest in middle ⅓, apeX with very slight downwards curvature; temones 1.04–1.12 × as long as body of penis ( Fig. 1C ). Copulatory sclerite with left arm refleXed outward and curving slightly upward apicad in dorsal view, setae at base about a ⅓ as long as arm, left area of body wider than right ( Fig. 1D ). Spiculum gastrale posteriorly curved.

Life history

Specimens were observed in large numbers during daytime in a small patch of forest in the Citrusdal area (JHAR3020). Adults were found on the leaves of trees and on the lower branches, where vegetation was very dense ( Fig. 4A–B ). The absence of specimens in the fynbos surrounding this patch (intensively sampled) suggests that E. pustulatus has a preference for forest habitat. This species was sampled on Galenia africana ( Aizoaceae ) by R. Borovec, but no specific host could be identified by the second author while sampling. Adults were collected in November.

Distribution

This species appears to occur naturally around the Citrusdal area and north towards the Olifants River ( Fig. 4D ).

Remarks

The species is morphologically variable, in size, relative size of callosities, colour and morphological ratios, even within populations. Larger scale genetic analysis will be necessary to determine whether cryptic species occur within this species concept.

Figures

Fig. 1. Epibrithus pustulatus Marshall, 1955, ♂, (JHAR03020-01; CBGP). A. Habitus, dorsal view. B. Habitus, lateral view. C. Penis, dorsal (left) and lateral (right) views. D. Copulatory sclerite (b = body; l = left arm; r = right arm; s = setae at base). E. Abdominal ventrites. F. Head and rostrum, lateral view. Scale bar: A–B = 5 mm; C–F not to scale.

Fig. 4. Distribution and habitat of Epibrithus spp. A. Forest patch in the Citrusdal area, biotope for E. pustulatus. B. E. pustulatus in natura, The Baths, Citrusdal. C–D. Distribution maps of Epibrithus spp. in the Western inland region of the Cape Floristic Region: black circle: E. pustulatus; white circle: E. longicarinatus Haran & Hansen sp. nov.; triangles: E. boroveci Haran & Hansen sp. nov. Imprecise localities from museum specimens are not shown.

Fig. 5. PhyML phylogram of species of Epibrithus Marshall, 1955 inferred from the 658 bp region of the mitochondrial Cytochrome oxidase I (COI) gene fragment, utilizing Phlyctinus callosus Schoenherr, 1826 as an outgroup. Bootstrap support values from 1000 repeats are shown: * = 64, ** = 100.