Description of five new species in the genus Phlyctinus Schoenherr (Coleoptera, Curculionidae): a first step in deciphering the P. callosus complex

Phlyctinus callosus (Schoenherr, 1826) (Curculionidae, Entiminae, oosomini) is a species native to the Western Cape province of the republic of South Africa. It is regarded as a key pest of orchards and vineyards. Detailed observations of its morphology and ecology have shown this species to be a complex of closely related species. In this study we describe the species of this complex, provide morphological and molecular diagnostic tools to distinguish between species, and review their distribution and host plant associations. In all, six species are recognized in the P. callosus complex and five are described as new (P. grootbosensis Haran sp. nov., P. xerophilus Haran sp. nov., P. planithorax Haran sp. nov., P. littoralis Haran sp. nov., P. aloevorus Haran sp. nov.). Sequences of the mitochondrial gene used (cytochrome oxidase I, COI) indicated that P. xerophilus Haran sp. nov. might comprise several cryptic species for which stable morphological features could not be identified at this stage. The species of the genus Phlyctinus appear to be primarily associated with various Asteraceae found in humid, sandy and disturbed habitats.


Introduction
However, there have been some indications that P. callosus might constitute a complex of closely related species. Barnes & Pringle (1988) first reported poor efficacy of insecticides on some populations of P. callosus in the Elgin Area of the Western Cape, but no difference in sensitivity to insecticides could be established under laboratory conditions between what they called 'strains'. More recently, Pringle et al. (2015) reported the unpredictable population dynamics of this weevil and the inconsistency of its host plants across regions and countries. In addition, a morphological study of the species showed that several features were variable across its distribution range, raising doubts as to its identity in different regions.
In this study we used an integrative taxonomic approach to decipher the P. callosus species-complex. Traditional recognition of species based on morphology was combined with sequencing of the standard DNA Barcode fragment (COI). Five new species are described, and morphological and molecular diagnostic tools to distinguish between the species are provided. The distribution and host plant associations of the species are updated and the implication of this complex of species for pest management is discussed.

Sampling
Dry-mounted specimens were borrowed from collections housed in South African museums (Iziko South African Museum, Cape Town; Ditsong Museum, Pretoria; South African National Collection of Insects, Pretoria; Stellenbosch University Collection, Stellenbosch) and some European museums (Natural History Museum, London, United Kingdom; Swedish Museum of Natural History, Stockholm, Sweden). Fresh specimens of Phlyctinus were also sampled in agro-ecosystems and surrounding natural vegetation across South Africa, with a focus on the Western Cape province. Specimens were collected either by beating/sweeping the vegetation at night or by a visual search at the base of plants during the day. After collecting, specimens were stored in 96% ethanol at ambient temperature.

Preparation and taxonomic treatment
The abdomens of adult specimens were extracted and digested in KoH to obtain clean preparations of genital structures, as these are commonly used to distinguish between species in Entiminae (Borovec & Skuhrovec 2018; Borovec 2019). The habitus and male genitalia were photographed using a Keyence ® VHX5000 imaging system. Most morphological characters used to distinguish between species of Phlyctinus are found on the ventrites and the penis of the male, so these structures should be properly prepared for identification. The copulatory sclerite of the penis of the male is informative for species identification, but it is usually hidden by the teguments of the endophallus and should be dissected as well. This sclerite shows a complex structure, forming a 'Y' in dorsal view. The two apical expansions, hereafter called 'arms', vary between species in terms of length, curvature and pilosity. The base of the 'Y', hereafter called the 'body', also varies in length and shape. Females of Phlyctinus show very few stable morphological differences between most species and cannot be used alone for identification. As knowledge stands, female terminalia (sternite VIII, spermatheca and gonocoxites) do not provide diagnostic characters either to distinguish between species. A description of these structures is provided for the species P. callosus only. Measurements were taken with an optical micrometer. Body length refers to the distance from the apical margin of the head (excluding the rostrum) to the apex of the elytra in dorsal view. rostrum length refers to the distance between the anterior margin of the eyes and the apex of the rostrum. The width to length ratio (w/l) was measured at the widest point of the rostrum, prothorax, the elytra and the penis (body). The length of the elytra was measured between the anterior part of the scutellum and the apex of the elytra in dorsal view. The length of the penis was measured between the base and the apex of the penis body (apodemes excluded). The terminology used follows Lyal (2019). The identity of Phlyctinus callosus was established by comparison with type material and the original description. The designation of a lectotype for this species follows ICZN code article 74. All new species are authored by the first author of this article.

Molecular analysis
For each species, specimens were sequenced for the standard DNA Barcode region (Hebert et al. 2003) to support the interspecific differences identified from the morphological study (Table 1). DNA was extracted from whole specimens, or a leg, using a DNeasy Blood & Tissue kit (Qiagen, Hilden, Germany). PCR amplification was carried out using a mix of primers for amplification of the standard Barcode region (mitochondrial cytochrome c oxidase subunit I, COI) of invertebrates (Appendix 1).  (Haran et al. 2015). Uncorrected p-distance values of pairwise genetic distances between species were computed with Mega 7 (Kumar et al. 2016). Preliminary reconstruction of interspecific phylogenetic relationships was carried out on COI sequences using PhyML (Guindon & Gascuel 2003) with 1000 bootstrap replicates.

Etymology
The genus and species names were probably named after the callosities present on the apex of the elytra in adults.
Colour. Body integument dark red, head and prothorax darker, usually black; vestiture of elytra consisting of a mixture of elongate scales, twice as long as wide, and smaller scales 4-5 × as long as wide, not concealing integument; scales brown and/or pearly green or pearly brown, pale scales usually forming a transverse band on apical ⅔ of elytra, longitudinal bands on basal half of sides of prothorax and a few dots on apical margin of prothorax.
head. rostrum longer than wide (w/l ratio: 0.68) in both sexes, at base 1.05 × as wide as at apex, sides slightly concave near middle of length; epifrons as wide as width of one eye, narrower at base than distance between eyes, sides subparallel, upper face with a longitudinal carina extending from basal transverse groove to nasal plate, visible through scales; nasal plate V-shaped, reaching level of antennal insertion basally, bare of scales, with only minute setae inserted in scattered punctures and 3 pairs of long setae apically near insertion of mandibles (2 short and 1 very long); antennal scrobes slightly curved in lateral view, directed to middle of eye, separated from it by a strip of scales narrower than diameter of eyes; mandibles trisetose, bare of scales. Forehead with a short longitudinal furrow between eyes, scales and setae arranged centripetally towards a point below base of eyes. Eyes protruding, surface strongly conical in dorsal view. Antennae slender, scape 0.75 × as long as funicle, slightly bisinuate, subclavate at apex, exceeding anterior margin of prothorax in repose; funicle with segments 1-2 elongate, 1 shorter (0.65 ×) than 2, segments 3-6 longer than wide, conical, shortening apicad, segment 7 longer and slightly wider than 6; club spindle-shaped, segment 1 longer than 2, margins slightly sinuous.
Prothorax. Slightly wider than long (w/l ratio: 1.16), widest slightly before middle of length, apical margin 0.68 × as wide as at base, sides rounded, apical half slightly concave; integument forming a dense cover of elongate granules orientated parallel to median carina and two slight depressions on each side of median carina; median carina raised, smooth and shiny, not reaching apical and basal margins of prothorax.
aBdomen. Underside with pearly green or pearly brown scales, not concealing integument, more condensed on metanepisterna; ventrite 1 as long as 2 + 3 + 4, slightly convex in middle (♀), or concave with erect setae as long as claws (♂), ventrite 5 slightly longer than 3 + 4, with erect setae in middle and near apex and a small tubercle near apex (♀), or with a large cavity in apical ⅔, with long erect setae condensed on margin of cavity, forming two brushes at apical and basal margins, and a longitudinal line of short recumbent setae in cavity (♂) (Fig. 3A).
legs. Femora clavate, unarmed, with a ring of more condensed pale scales near middle; tibiae straight, unarmed, slightly bisinuate on ventral side, apical setal comb equal in length, golden; metatibial corbels absent; claws simple, free, equal in length.
genitalia (male terminalia). Body of penis elongate, 0.7 × as long as apodemes, sides convex, widest in basal ⅓, converging towards apex and slightly narrowed before it (ratio w/l: 0.45), in lateral view curvature weak, mainly in basal half, and just before apex ( Fig. 2A); copulatory sclerite with left arm as long as body, bearing setae at base, comb of right arm with setae parallel, right area of body wider than left area.
Female terminalia. Sternite VIII with plate subtriangular in dorsal view, apically sharply pointed, widest near basal ⅓, in lateral view lanceolate, widest near middle of length, anterior margin well developed, glabrous, posterior margin ill-defined up to middle of length of plate; apodeme short, robust, as long as or slightly longer than length of plate; transverse bar moderately sclerotised. Gonocoxites long, flat, sides converging apicad, rounded at apex, with long apical styli 4 × as long as wide, bearing long apical setae. Spermatheca with regularly wide curved cornu; ramus well developed, twice as long as collum, ramus and collum parallel; nodulus rounded.

Sexual dimorphism
Males may be distinguished externally from females by the slightly more slender elytra and the cavity and setae on ventrite 5.

Life history
Phlyctinus callosus is a polyphagous species. Verified host plants belong to the families Amaryllidaceae (ornamental Tulbaghia spp.), Asteraceae (Osteospermum moniliferum L., ornamental Gazania sp.), Apiaceae (larvae have been artificially bred on Daucus carota L.), Aizoaceae (ornamental Lampranthus sp.), Crassulaceae (Cotyledon orbiculata L., Cotyledon spp.), Geraniaceae (ornamental Pelargonium sp.), Plantaginaceae (Plantago lanceolata L.) and Plumbaginaceae (ornamental Plumbago auriculata Lam.). This species is often found in gardens on ornamental plants. In natural habitats it was only found on O. moniliferum occurring in humid, sandy habitats such as river banks. Adults spend the day in the leaf litter on the ground in the vicinity of the host plant (Fig. 4A) and climb onto its aerial parts during the night to feed and mate. Adults may be found all year round if the habitat remains wet.

Distribution
Phlyctinus callosus is endemic to the Western Cape province of the republic of South Africa. Museum records suggest that this species is naturally distributed around Cape Town and on the Cape Flats. In other localities (Cederberg, Little Karoo, etc.) it has only been found in the vicinity of gardens and orchards, suggesting human-mediated transportation. The records of the species from the Eastern Cape province  (Schoenherr, 1826 also probably correspond to human-mediated introductions. Phlyctinus callosus has been introduced into the following countries: Australia, New Zealand, Norfolk Island, reunion Island and St Helena Island. The records from the Kermadec and Ascension Islands could not be verified and should be temporarily considered as referring to Phlyctinus species. This species has been detected, but seemingly not established, in the Northern Hemisphere: Britain (Brown 2004) and the USA (Anonymous 1950).

Remarks
In the collection of Schoenherr housed at NHrS, two males and two females from the type locality (Cape of Good Hope) and fitted with type and paratype labels were located under the name P. callosus. However, the description of this species lacks a designation of a particular specimen as the holotype (Schoenherr 1826). The male specimen from this series bearing a red type label (NHrS JLKB000065427) is designated as the lectotype for P. callosus (Schoenherr 1826). The second male of this series (NHrS JLKB000065428) bears a red paratype label, but belongs to a different, undescribed species, and will not be dealt within this paper. The two females of this series (NHrS JLKB000065429, NHrS JLKB000065430) were labelled as paralectotypes for P. callosus.
In the Wollaston collection housed at BMNH, the syntypic series of Sciobius subnodosus Wollaston, 1869 (1 ♂, 2 ♀♀) from St Helena Island was located. The male specimen of this series is designated (above) as the lectotype for S. subnodosus. The two female specimens are labelled as paralectotypes of this species name. The examination of these specimens revealed no external or internal differences from the holotype of Phlyctinus callosus as reported in Decelle & Voss (1972). The name P. callosus var. tottus Sparrman, 1785 (as listed by Lona 1937) does not refer to any species description of Sparmann and should be considered as an in litteris invalid name. The type material of Ocynoma rhysa olliff, 1888 and Rhyncogonus germanus Broun, 1893 could not be located in the context of this study. These names are reported as synonyms of P. callosus by  and Pullen et al. (2014).
Uncorrected genetic p-distances of COI reached 1.6% among all the specimens of this species as analyzed (Fig. 5).
Colour. Body integument black, legs black to dark red; vestiture of elytra consisting of a mixture of scales, either isodiametric to twice as long as wide, pearly white or smaller, 3 × as long as wide, brown, not concealing the integument; pearly white scales forming series of pale dots on interstriae or illdefined transverse bands, and a band on basal half of sides of prothorax.
head. rostrum longer than wide (w/l ratio: 0.67) in both sexes, at base 1.05 × as wide as at apex, sides slightly concave near middle of length; epifrons in middle as wide as width of eye, at base narrower than distance between eyes, sides subparallel, slightly expanding apicad, upper face with a longitudinal carina extending from basal transversal groove to nasal plate, visible through scales; nasal plate V-shaped, reaching level of antennal insertion basally, bare of scales, with only minute setae inserted in scattered punctures and 3 pairs of long setae apically near insertion of mandibles (2 short and 1 very long); antennal scrobes slightly curved in lateral view, directed to middle of eye, separated from it by a strip of scales ¼ as wide as width of eyes; mandibles trisetose, bare of scales. Forehead with a short longitudinal furrow between eyes, scales and setae arranged centripetally towards a point below base of eyes; eyes moderately protruding, margin slightly more convex basally than apically. Antennae slender, scape 0.70 × as long as funicle, slightly bisinuate, subclavate at apex, exceeding anterior margin of prothorax in repose; funicle with segments 1-2 elongate, 1 shorter (0.82 ×) than 2, segments 3-6 longer than wide, conical, shortening apicad, segment 7 longer and slightly wider than 6; club spindle-shaped, segment 1 longer than 2, margins slightly sinuous.
Prothorax. Slightly wider than long (w/l ratio: 1.16), widest slightly before middle of length, apical margin 0.58 × as wide as at base, sides sub-straight in apical and basal ½, almost angular at widest point; integument forming a dense cover of elongate granules forming concentric ellipses around a point located on basal ⅓ of median line and a pair of slight depressions on each side of this point; median carina absent, integument not forming a smooth and shiny ridge. elytra. Sides convex, widest before middle of length (w/l ratio: 0.72-0.77), integument smooth or weakly reticulate, shiny or matt, interstriae raised, 2-4 × as wide as width of striae in basal half; declivital callosities present on apical ¼ of interstriae 3, 5 and 7 and smaller ones on 2, 4, 6 and 8; each interstria with a series of semi-erect, elongate whitish scales, condensed on callosities.
aBdomen. Underside with pearly green or pearly white scales, not concealing integument, not condensed on metanepisterna; ventrite 1 slightly shorter than 2 + 3 + 4, slightly convex in middle (♀), or concave with very long, erect golden setae much longer than claws (♂), ventrite 5 longer than 3 + 4, with erect setae in middle and near apex and a reticulate ridge near apex (♀) or with a large cavity in apical ⁴⁄5, with long erect setae, similar to those on ventrite 1, condensed on 2 brushes on each side of margin of cavity; setae in bottom of cavity erect, golden, shorter than those on margin (♂) (Fig. 3B); in males, middle of ventrites 1-4 with an elongate cuticular ridge at base of setae.
legs. Femora clavate, unarmed, with a ring of more condensed pale scales near middle; tibiae straight, unarmed, slightly bisinuate on ventral side; in males apex of metatibia with a brush of golden setae ventrally; claws simple, free, equal in length.
genitalia. Body of penis short, 0.6 × as long as apodemes (w/l ratio: 0.48), sides subparallel in basal half, widest near base, concave in apical ⅓, tapering towards apex; apex pointed; in lateral view curvature weak, mainly in basal half, bisinuate near apex (Fig. 2B); copulatory sclerite with left arm shorter than body, bearing setae at base, comb of right arm with setae converging and forming a spiral; right area of body as wide as left area.

Sexual dimorphism
Males might be distinguished externally from females by the slightly more slender elytra and the two brushes of erect golden setae on ventrites 1 and 5.

Life history
This species was found to be abundant on and at the base of Osteospermum moniliferum, Senecio halimifolius L. and S. burchellii, which are probably its host plants (Fig. 4D).

Distribution
Phlyctinus grootbosensis sp. nov. is only known from the type locality, the Grootbos Private Nature reserve near Gansbaai.

Remarks
Phlyctinus grootbosensis sp. nov. can easily be distinguished from other species by the long golden setae on ventrites 1 and 5 of the males. It is the darkest species of the genus and has the most strongly rounded eyes in dorsal view (more or less angled in the other species). Its body shape and colour resemble the dry fruits of Osteospermum moniliferum remarkably well (Fig. 4C).
Colour. Body integument dark red, head and prothorax darker, usually black; vestiture of elytra consisting of a dense cover of small, elliptic scales, slightly longer than wide, not completely concealing integument; scales pale brown with spots of pearly green scales generally forming a transverse band in apical ⅔ of elytra, a short strip at base on 3 rd interstria, longitudinal bands on basal half of sides of prothorax and a few dots on apical margin of prothorax.
head. rostrum longer than wide (w/l ratio: 0.80) in both sexes, base as wide as apex, sides slightly concave near middle of length; epifrons as wide at base as width of eye, at base narrower than distance between eyes, sides widening from base to apex, upper face with a longitudinal carina extending from basal transverse groove to nasal plate, visible through scales; nasal plate V-shaped, reaching level of antennal insertion basally, bare of scales, with short setae inserted in scattered punctures and 3 pairs of long setae apically near insertion of mandibles (2 short and 1 very long); antennal scrobes slightly curved in lateral view, directed to middle of eye, separated from it by a strip of scales as wide as diameter of eyes; mandibles trisetose, bare of scales. Forehead with a short longitudinal furrow between eyes, scales and setae arranged centripetally towards a point below base of eyes. Eyes protruding, surface almost conical in dorsal view. Antennae slender, scape 1.25 × as long as funicle, slightly bisinuate, subclavate at apex, exceeding anterior margin of prothorax in repose; funicle with segments 1-2 elongate, 1 shorter (0.70 ×) than 2, segments 3-7 longer than wide, conical, 3-5 shortening apicad, 5-6 widening apicad; club spindle-shaped, segment 1 longer than 2, margins slightly sinuous.
Prothorax. Slightly wider than long (w/l ratio: 1.20), widest slightly before middle of length, apical margin 0.75 × as wide as base, sides rounded, apical half slightly concave; integument forming a dense cover of elongate granules orientated parallel to median carina and two slight depressions on each side of median carina; median carina raised, smooth and shiny, not reaching apical and basal margins of prothorax.
aBdomen. Underside with pearly green or pearly brown scales, not concealing integument, more condensed on metanepisterna; ventrite 1 shorter than 2 + 3 + 4, slightly convex in middle (♀) or concave with erect setae slightly shorter than claws (♂), ventrite 5 longer than 3 + 4, with erect setae in middle and near apex and a smooth longitudinal carina (♀) or with large cavity extending on apical ⅔, with long erect setae condensed on margins and along a longitudinal line at bottom of cavity (♂) (Fig. 3C).
legs. Femora clavate, unarmed, with a ring of more condensed pale scales near middle; tibiae straight, unarmed, slightly bisinuate on ventral side; claws simple, free, equal in length.
genitalia. Body of penis short, 0.5 × as long as apodemes, sides bisinuate, widest above middle of length, converging from there towards apex, apex pointed (w/l ratio: 0.50), in lateral view curvature weak and regular (Fig. 2C); endophallus with a sclerotised plate forming a square angle below base of body of penis; copulatory sclerite with left arm as long as body, strongly curved inwards, not bearing setae; comb of right arm with setae converging; right area of body wider than left area.

Sexual dimorphism
Males may be distinguished externally from females by the cavity and setae on ventrite 5.

Life history
Adults of P. xerophilus sp. nov. have been found at the base of vines and Plantago lanceolata plants in table grape vineyards (Fig. 4B). The host plants of the larvae are unknown. Adults were collected in January, July, September and December.

Distribution
As currently known, this species seems to occur naturally in the region of robertson and the Hex river valley.

Remarks
Phlyctinus xerophilus sp. nov. is similar to P. callosus but differs from it by the erect setae along the median line of the cavity of ventrite 5 of the males (Fig. 3C). It is also slightly larger, more elongate and has larger elytral tubercles on the declivity than P. callosus. Females of the two species are difficult to distinguish morphologically. As knowledge stands, there seems to be only a small overlap between their distribution ranges and therefore the geographical origin of specimens can assist in their identification. The two species can also be distinguished using their COI sequences, which show divergences ranging from 9.2 to 9.8%.
The sequencing of other specimens morphologically similar to P. xerophilus sp. nov. (Table 1) showed that this species contains at least four mitochondrial lineages (Fig. 5) found in populations from distinct localities. Uncorrected p-distances between all these lineages ranged from 5.5 and 8.5%. Preliminary observations made on series of specimens from these localities showed subtle morphological differences that suggest that this species could be a complex of closely related or cryptic species. A formal treatment of this complex has not been undertaken here due to limited fresh material available. It will be the focus of a future study. All specimens found to date run to P. xerophilus sp. nov. in the key provided. As knowledge stands, only the specimens described formally here as P. xerophilus sp. nov. are agricultural pests. other specimens were found in natural or semi-natural habitats. Haran sp. nov. urn:lsid:zoobank
Colour. Body integument black; vestiture of elytra consisting of elliptical scales, twice as long as wide, not concealing integument; scales pale or dark brown with scattered contrasting pearly green spots and an ill-defined transverse pale band on apical ⅔ of interstriae 1-3, mainly visible in females.
head. rostrum longer than wide (w/l ratio: 0.77) in both sexes, as wide as base at apex, sides slightly concave near middle of length in dorsal view; epifrons as wide as width of eye, at base narrower than distance between eyes, sides subparallel, upper face with a longitudinal carina extending from basal transverse groove to nasal plate, visible through scales; nasal plate V-shaped, reaching level of antennal insertions basally, bare of scales, with only minute setae inserted in scattered punctures and 3 pairs of long setae apically near insertion of mandibles (2 short and 1 very long); antennal scrobes slightly curved in lateral view, directed to middle of eye, separated from it by a strip of scales slightly narrower than diameter of eyes; mandibles trisetose, bare of scales. Forehead with a short longitudinal furrow between eyes; recumbent and suberect scales arranged centripetally towards a point below base of eyes, in dorsal view; eyes protruding, surface almost conical in dorsal view. Antennae slender, scape 0.75 × as long as funicle, slightly bisinuate, subclavate at apex, exceeding anterior margin of prothorax in repose; funicle with segments 1-2 elongate, 1 very slightly shorter (0.95 ×) than 2, segments 3-6 longer than wide, conical, shortening apicad, segment 7 longer and slightly wider than 6; club spindle-shaped, segment 1 longer than 2, margins slightly sinuous.
aBdomen. Underside with pearly green scales, scattered, not overlapping; ventrite 1 shorter than 2 + 3 + 4, slightly convex in middle (♀) or concave with erect setae as long as claws (♂), ventrite 5 as long as 3 + 4, with sub-erect setae in middle and near apex (♀) or with a large cavity extending on apical ⁴⁄5, with long erect setae condensed on margin of cavity, forming two brushes at apical and basal margins, and a longitudinal line of erect setae in cavity, long in basal half and very short in apical half (♂) (Fig. 3D).
genitalia. Body of penis elongate, 0.65 × as long as apodemes, sides convex, widest in basal ¼ (w/l ratio: 0.44), in lateral view curvature weak (Fig. 2D); copulatory sclerite with left arm longer than body, not bearing setae at base; comb of right arm with setae converging, curved inward at apex; right area of body slightly wider than left area.

Sexual dimorphism
Males may be distinguished externally from females by the presence of a cavity and setae on ventrite 5. They usually lack a distinct transverse pale band on the elytra (visible on interstriae 1-3 in females).

Life history
All known specimens of P. planithorax sp. nov. have been collected at the base of Hymenolepis crithmifolia (Asteraceae) and Carpobrotus edulis (Aizoaceae) plants, which are probably its host plants (Fig. 4E-F). This species was not found on other plants present at the collection sites. Adults were collected in April and November.

Distribution
This species is only known from several sites of the western slope of the Kogelberg Mountain.

Remarks
Phlyctinus planithorax sp. nov. belongs to the P. littoralis sp. nov. species group and is similar to the other species included in it. Based on the series examined, it can be distinguished from them by the absence of a carina on its prothorax and by the erect scales on ventrites 1-4, which are more than twice as long as the recumbent scales (less than twice as long in P. littoralis sp. nov. and P. aloevorus sp. nov.). Phlyctinus planithorax sp. nov. is genetically closest to P. aloevorus sp. nov., the two species showing an interspecific uncorrected p-distance of 5.2%. The arrangement of erect setae on ventrite 5 of this species is similar to that of P. xerophilus sp. nov., but the erect setae on the median line are shorter and do not reach the apex of the cavity. Despite an intense search for Phlyctinus species in coastal habitats in the Western Cape province, this species was only found at the vicinity of its type locality.  Colour. Body integument dark red, head and prothorax darker, usually black; vestiture of elytra with elliptic elongate scales, twice as long as wide, not concealing integument, greyish, forming a homogeneous grey appearance, usually with an ill-defined paler band on apical ⅔ of interstriae 1-3.

Phlyctinus littoralis
head. rostrum longer than wide (w/l ratio: 0.63) in both sexes, at base as wide as at apex, sides slightly concave near middle of length; epifrons slightly narrower in middle of length than width of eye in dorsal view, at base narrower than distance between eyes, sides subparallel, slightly widening apicad, upper face with a longitudinal carina extending from basal transverse groove to nasal plate, visible through scales; nasal plate V-shaped, reaching level of antennal insertion basally, bare of scales, with only minute setae inserted in scattered punctures and 3 pairs of long setae apically near insertion of mandibles (2 short and 1 very long); antennal scrobes slightly curved in lateral view, directed to middle of eye, separated from it by a strip of scales half as narrow as diameter of eyes; mandibles trisetose, bare of scales. Forehead with a short longitudinal furrow between eyes, scales and setae arranged centripetally towards a point below base of eyes; eyes protruding, margin rounded, surface slightly conical in dorsal view. Antennae slender, scape 0.8 × as long as funicle, slightly bisinuate, subclavate at apex, exceeding anterior margin of prothorax in repose; funicle with segments 1-2 elongate, 1 slightly shorter (0.85 ×) than 2, segments 3-6 longer than wide, conical, shortening apicad, segment 7 longer and slightly wider than 6; club spindle-shaped, segment 1 longer than 2, margins slightly sinuous.
Prothorax. Slightly wider than long (w/l ratio: 1.20), widest near middle of length, apical margin 0.6 × as wide as basal margin, sides rounded, apical half slightly concave; integument densely punctate, spaces between punctures forming ill-defined, concentric smooth ridges and a small, smooth and shiny median carina visible in approximately 50% of individuals; upper face regularly convex, lacking depressions. elytra. Sides convex, widest near middle of length (w/l ratio: 0.76-0.83), integument finely punctate and reticulate, shiny, interstria raised, 3-4 × as wide as width of striae in basal half; large declivital callosities absent or very reduced in apical ¼ of interstriae 3, 5 and 7; each interstria with a series of semi-erect elongate whitish scales, slightly more condensed in spots on declivity.
aBdomen. Underside with scattered scales similar to those on elytra, not concealing integument; ventrite 1 as long as 2 + 3 + 4, slightly convex in middle (♀), or concave with erect setae as long as claws (♂), ventrite 5 longer than 3 + 4, with recumbent elongate setae in middle and near apex and a weak longitudinal carina near apex (♀) or with a large cavity extending over apical ⅔, with long erect setae mainly condensed on middle of basal margin of cavity and a brush on either side of apical margin; bottom of cavity with a few short recumbent or semi-erect setae (♂).
legs. Femora clavate, unarmed, with a double vestiture of recumbent and semi-erect greyish scales; tibiae straight, unarmed, slightly bisinuate on ventral side; claws simple, free, equal in length.
genitalia. Body of penis elongate, 0.75 × as long as apodemes, sides almost straight, converging regularly towards apex, more abruptly near apex, widest at base (w/l ratio: 0.40), in lateral view curvature weak, slightly stronger near middle of length (Fig. 2E); copulatory sclerite with left arm longer than body, not bearing setae at base; comb of right arm with setae converging; right area of body slightly wider than left area.

Sexual dimorphism
Males may be distinguished externally from females by the slightly more slender elytra (w/l ratio: 0.76, 0.83 in ♀) and the cavity and setae on ventrite 5.

Life history
The type series of P. littoralis sp. nov. was collected from the base of Arctotis angustifolia (Asteraceae) plants growing on the gravel parts of Kogel Bay beach (Fig. 4G-H). Adults were collected between May and September but gravid females only in May.

Distribution
This species is only known from its type locality.

Remarks
Phlyctinus littoralis sp. nov., P. planithorax sp. nov. and P. aloevorus sp. nov. form a species group characterized by the presence of only very small or no tubercles on the elytral declivity and short setae on ventrite 1 of the males. Preliminary phylogenetic analysis of COI sequences indicated that they form a distinct genetic cluster (Fig. 5). They have so far only been found in coastal habitats. Phlyctinus littoralis sp. nov. is most closely related to P. planithorax sp. nov., from which it can easily be distinguished by its homogeneous grey vestiture. The two species show an interspecific genetic p-distance on COI of 4.6%.
Colour. Body integument dark red, head and prothorax darker, usually black; vestiture of elytra with elliptic elongate scales, twice as long as wide, not concealing integument; scales brown with scattered ill-defined paler spots, in females with a pale transverse band on apical ¼ of interstriae 1-3.
head. rostrum longer than wide (w/l ratio: 0.72) in both sexes, at base as wide as at apex, sides slightly concave near middle of length; epifrons slightly narrower in middle of length than width of eye in dorsal view, at base slightly narrower than distance between eyes, sides subparallel, slightly widening apicad, upper face with a longitudinal carina extending from basal transverse groove to nasal plate, visible through scales; nasal plate V-shaped, reaching level of antennal insertion basally, bare of scales, with only minute setae inserted in scattered punctures and 3 pairs of long setae apically near insertion of mandibles (2 short and 1 very long); antennal scrobes slightly curved in lateral view, directed to middle of eye, separated from it by a strip of scales half to ⅓ narrower than diameter of eye; mandibles trisetose, bare of scales. Forehead with a short longitudinal furrow between eyes, scales and setae arranged centripetally towards a point below base of eyes; eyes protruding, margin rounded, surface moderately conical in dorsal view. Antennae slender, scape 0.7 × as long as funicle, bisinuate, subclavate at apex, exceeding anterior margin of prothorax in repose; funicle with segments 1-2 elongate, 1 slightly shorter (0.87 ×) than 2, segments 3-6 longer than wide, conical, shortening apicad, segment 7 longer and slightly wider than 6; club spindle-shaped, segment 1 longer than 2, margins slightly sinuous.
Prothorax. Slightly wider than long (w/l ratio: 1.18), widest before middle of length, apical margin 0.7 × as wide as basal margin, sides rounded, apical half slightly concave; integument densely punctate, with shiny elongate concentric ridges and a median carina; upper face regularly convex, lacking cuticular depression.
elytra. Sides convex, widest near middle of length (ratio w/l: 0.79-0.83), integument finely punctate and reticulate, shiny, interstriae raised, 3-4 × as wide as width of striae in basal half; large declivital callosities absent or very reduced in apical ¼ of interstriae 3, 5 and 7; each interstria with a series of semi-erect, elongate pale brown scales, slightly more condensed on callosities.
aBdomen. Underside with scattered scales similar to those on elytra, not concealing integument; ventrite 1 shorter than 2+3+4, slightly convex in middle (♀) or concave with sub-erect setae shorter than claws (♂), ventrite 5 longer than 3+4, with recumbent elongate setae in middle and near apex and a weak longitudinal carina near apex (♀) or with a large cavity extending over apical ¾, with long erect setae mainly condensed at middle of basal margin of cavity and a brush on each side of apical margin; bottom of cavity with a few short recumbent or semi-erect setae (♂).
genitalia. Body of penis elongate, 0.75 × as long as apodemes, sides convex, widest slightly before middle of length (w/l ratio: 0.36), in lateral view curvature weak, stronger near base (Fig. 2F); copulatory sclerite with left arm longer than body, bearing setae at base; comb of right arm with setae converging, curved, straight at apex; right area of body slightly wider than left area.

Sexual dimorphism
Males may be distinguished externally from females by the homogenous elytral vestiture (with a transverse pale band in apical ⅓ in females), and the cavity and erect setae on ventrite 5.

Life history
Phlyctinus aloevorus sp. nov. (Fig. 4I) forms large populations on Aloe arborescens (Asphodelaceae) and, to a lesser extent, on Carpobrotus edulis (Aizoaceae). Contrary to other species of the genus, which spend the day sheltering in the leaf litter, P. aloevorus sp. nov. was found hidden between the young leaves of Aloe L. during the day (Fig. 4J), feeding mainly on flower peduncles (Fig. 4J). Adults were collected in March and November.

Discussion
This study showed that the genus Phlyctinus is not monotypic but contains several closely related species. The examination of morphological features and the preliminary phylogenetic analysis based on COI sequences allowed the recognition of six species, five of them being described here as new. Four species groups were identified; the P. callosus, P. grootbosensis sp. nov., P. xerophilus sp. nov. and P. littoralis sp. nov. groups. The P. littoralis sp. nov. group comprises three closely related species inhabiting the southern coast of the Western Cape province. The P. xerophilus sp. nov. group contains several mitochondrial lineages that may represent several cryptic species. This group is found mostly in the inland area of the province and requires verification. This study highlighted the importance of conducting detailed integrative taxonomic studies for economic pests.
From an applied perspective, two of the species of this genus are currently treated as pests in orchards and vineyards, P. callosus and P. xerophilus sp. nov. Although morphologically similar, they can readily be distinguished by their size and by the different arrangements of erect setae on ventrite 5 of the males. As Phlyctinus species are often transported by humans, determining the natural range of the species is challenging. However, the samples obtained in the course of this study suggest that P. xerophilus sp. nov. has a narrower range than P. callosus, being restricted to inland valleys of the Worcester region. More detailed research is needed to determine their exact distribution ranges, host plants and climatic niches, because they could have been confused in previous studies (Barnes 1989). Identifying the host range of P. xerophilus sp. nov. and of Phlyctinus species in general is critical in the context of the growing use of cover crops in orchards and vineyards (Schipanski et al. 2014;Thierfelder et al. 2018). The host records listed in this study suggest that the genus Phlyctinus is mainly associated with Asteraceae growing in wet and naturally disturbed coastal and riparian habitats. The apparent preference of Phlyctinus for these habitats probably explains its harmfulness in fields of irrigated crops.