Derelomus costiger Marshall, 1958

Derelomus costiger Marshall, 1958

Fig. 30 View Fig

Derelomus costiger Marshall, 1958: 741 .

Psilocaulus elatus Richard, 1958: 50 . Syn. nov.

Derelomus costiger – Haran et al. 2022a (phylogenetic relationships, life history); 2023a (life history).

Diagnosis

In the D. ephippiger group, this species can be distinguished by the combination of rostrum comparatively moderately long and downcurved ( Fig. 30C–D View Fig ), only 3.5 × as long as wide in dorsal view in males ( Fig. 30A View Fig ) and by the males lacking patterns of elytra and internal comb of elongate setae on protibiae. Derelomus costiger is similar to D. discus , but in the latter species males have a longer rostrum (4.75 × as long as wide) and bears combs of setae on protibiae ( Fig. 31D View Fig ). It is also close to D. ephippiger , but the latter species exhibit a distinct dark pattern at the base of elytra ( Fig. 32A View Fig ). The body of penis and the stridulatory plate are diagnostic for these species. GenBank accession numbers for the corresponding DNA barcodes: ON553421 View Materials –22–23/PV698475–76.

Material examined

Lectotype of Derelomus costiger Marshall, 1958 (here designated)

REPUBLIC OF SOUTH AFRICA • ♂; “Holotype [red label]” “South Africa; Stellenbosch [ Western Cape Province, 33°55′55.2″ S 18°52′30.0″ E]; 9.4.1957; J. G. Theron ” “ Derelomus ; costiger . Mshl; Type ♂” “LECTOTYPE ♂; Derelomus ; costiger ; Marshall, 1958; Haran des. 2025”; NHMUK.

GoogleMaps

Holotype of Psilocaulus elatus Richard, 1958

COMORO ISLANDS • ♂; “ Moheli; Fomboni [ 12°17′06.5″ S 43°44′38.9″ E]; XI.55-A.R” “Institut; Scientifique; Madagascar” “TYPE[red label]” “ Psilocaulus ; elatus n; type; Det. R. Richard” “ Derelomus ; costiger Mshl ; Haran det. 2024”; MNHN.

GoogleMaps

Paralectotypes

REPUBLIC OF SOUTH AFRICA – Western Cape Province • 1 ♂; Stellenbosch; 33°56′20.4″ S, 18°52′08.4″ E; 9 Apr. 1957; J. G. Theron coll.; CIE. n° 15595; NHMUK GoogleMaps • 3 ♂♂; same data as for preceding; SAMC. GoogleMaps

Other material

ANGOLA • 1 ♂; no precise locality; 7 Jun. 1928; NHMUK GoogleMaps • 1 ♂, 1 ♀; Huila district; 14°47′53.2″ S, 14°54′10.8″ E; Mus. Murray ; NHMUK. GoogleMaps

IVORY COAST • 1 ♂; Toumodi; 6°33′21.6″ N, 5°01′42.0″ W; 5 Oct 1963; R. Vuattoux coll.; flower of Phoenix sp. ; MNHN. GoogleMaps

KENYA • 2 ♂♂, 2 ♀♀; Makindu; 2°16′37.2″ S, 37°49′08.4″ E; May 1937; Mac Arthur coll.; NHMUK. GoogleMaps

MOZAMBIQUE • 1 ♀; Maputo Special Reserve , west gate; 26°30′14.4″ S, 32°43′05.0″ E; 21–30 Nov. 2016; Aristophanous M, Cristovae J Laszio G and Miles W coll.; light trap; NHMUK. GoogleMaps

REPUBLIC OF SOUTH AFRICA – Western Cape Province • 1 ♂, 1 ♀, 8 specs (preserved in ethanol); Stellenbosch, J. Marais Nature reserve ; 33°55′55.2″ S, 18°52′30.0″ E; 18 Jul. 2018; J. Haran coll.; on flowers of Buddleja auriculata ( Buddlejaceae ); JHAR01181 ; CBGP GoogleMaps • 1 ♀, 11 specs (preserved in ethanol); same data as for preceding; JHAR01182 ; CBGP GoogleMaps • 1 ♂, 1 ♀; Pringle Bay; 34°21′00.0″ S, 18°49′48.0″ E; 28 Nov. 2019; J. Haran coll.; on male inflorescence of Phoenix reclinata ; JHAR03078 - 01/04; CBGP. GoogleMaps – Eastern Cape Province • 1 ♂, 2 ♀♀; Kentani; 32°30′29.8″ S, 28°19′37.2″ E; H.P. Abernethy coll.; SAM-COL-A050313 ; SAMC GoogleMaps • 1 ♂, 3 ♀♀; Mbotyi, 31°27′10.8″ S, 29°44′49.2″ E; Dec. 2009; Ş. Procheş coll.; on male and female inflorescences of Phoenix sp. ; JHAR07434 ; CBGP. GoogleMaps – Gauteng Province • 1 ♂, 1 ♀; Pretoria; 25°46′23.2″ S, 28°12′32.4″ E; 22 Jun. 1990; S. Neser coll.; in flowers of Phoenix reclinata, SANC . GoogleMaps – KwaZulu-Natal Province • 4 ♂♂, 1 ♀, 30 specs (preserved in ethanol); St Lucia; 28°22′59.8″ S, 32°24′33.4″ E; 5 Jan. 2019; J. Haran coll.; male inflorescence of Phoenix reclinata ; JHAR02041 -0½042/2044; CBGP GoogleMaps • 1 ♂, 1 ♀, 7 specs (preserved in ethanol); iSimangaliso Wetland Park , Ozabeni, 3km SSW Sodwana Camp; 27°38′10.8″ S, 32°34′55.2″ E; 22 Oct. 2014; E Grobbelaar coll.; SANC-MCOL-0374/ JHAR02335 ; SANC. GoogleMaps – Limpopo Province • 1 ♂; Mmabolela Estate; 22°37′52″ S, 28°16′34″ E; 20–24 Nov. 1994; F. Genier coll.; savana light trap; CMNC. GoogleMaps

REUNION ISLAND ( FRANCE) • 1 ♂, 3 ♀♀; Sainte Marie; 20°53′53.2″ S, 55°32′56.4″ E; Feb. 2022; C. Lemagnen coll.; UV light trap in a garden; JHAR07813 ; EL. GoogleMaps

SENEGAL • 6 ♂♂, 30 ♀♀; Kayar; 14°54′57.6″ N, 17°07′08.4″ W; 8 Apr. 1951; Villiers coll.; in flowers of Phoenix dactylifera ; MNHN GoogleMaps • 3 ♂♂; same collection data as for preceding; NHMUK. GoogleMaps

UNITED STATES OF AMERICA • 1 ♂; Florida, Dade County Kendall, Old Cutler Road ; 25°37′55.0″ N, 80°18′39.9″ W; 25 Jul.–1 Aug. 2016; S. Haltbert coll.; air suction trap; CMNC GoogleMaps • 1 ♀; Florida, Palm Beach County, Delary Beach ; 26°25′56.8″ N, 80°05′52.2″ W; 4 Jul. 2020; V. Golia coll.; porch light; CMNC GoogleMaps • 1 ♂; Florida, Palm Beach County, Delary Beach ; 26°25′56.8″ N, 80°05′52.2″ W; 9 Nov. 2020; V. Golia coll.; porch light; CMNC. GoogleMaps

ZIMBABWE • 1 ♂; Victoria Falls; 17°56′42.0″ S, 25°50′21.6″ E; Aug. 1929; G.A.K. Marshall coll.; NHMUK. GoogleMaps

Redescription ( ♂)

MEASUREMENTS. Body length 2.5–2.8 mm.

COLOR. Body integument uniformly pale brown or with apical ⅔ of rostrum, club and post ocular area dark brown, some specimens with median line of pronotum darker than rest of integument; dorsum with minute recumbent whitish setae, glabrous in appearance.

HEAD. Rostrum as long as pronotum in lateral view, slightly and regularly downcurved; in dorsal view about 3.5× as long as wide, integument densely punctate, forming 5 longitudinal carinae; antennae inserted at apical 1/5 of length in lateral view; head capsule densely punctate in dorsal view, forehead flat; eyes convex, exceeding lateral curve of head capsule in dorsal view; antennal funicle with first segment 2× as long as wide, as long as segments 2–3 together, 3–7 transverse.

PRONOTUM. Wider than long (W: L ratio: 1.50–1.66), widest near base, a little narrower there than elytra at humeral angles (0.82 ×), side rounded, converging apicad, forming notch and blunt tooth near middle of length; apical constriction distinct, about as deep as width of scape in middle of length; integument with punctures rounded, space between punctures rough, shiny, micropunctate, wider or narrower than diameter of punctures in middle, narrower laterally.

METATHORAX. Metanepisterna with recumbent white setae, non-contiguous.

ELYTRA. A little longer than wide (W: L ratio: 0.84–0.92); sides strongly convex, widest near basal 2/5 of length; humeri not distinct from the lateral curvature of elytra; apex rounded, notched or jointed at level of suture; striae with punctures about ⅓ to ¼ as wide as width of interstriae; interstriae flat, 5 slightly raised on basal 3/5 of length; scutellar shield rounded, generally slightly darker than elytra, coated with small recumbent scales not concealing integument.

ABDOMEN. Underside uniformly pale brown, with minute recumbent whitish setae, not contiguous. Stridulatory plate with lines of 7–8 granules about ⅔× as long as median line from base, space between granules 1–2 × as wide as diameter of a granule. Central sclerotized area slightly longer than wide, truncate at base ( Fig. 30F View Fig ).

LEGS. Profemora moderately thickened near middle of length; protibiae with external margin straight, internal bisinuate, setae on apical half of internal margin recumbent, short, not contrasting with the setae of the rest of tibiae; claws simple.

TERMINALIA. Body of penis elongate (W: L ratio: 0.23), about 1.5 × as long as apodemes; sides slightly convex in dorsal view, widening regularly from base to apical ⅓, from there narrowing apicad, apex rounded; in lateral view curvature moderate but stronger in basal ½ of length, width narrowing regularly from basal ½ of length to apex, apex bisinuate ( Fig. 30E View Fig ).

Sexual dimorphism

Females can be distinguished from males by the rostrum which is slightly longer (1.15 × as long as pronotum in lateral view) and narrower ( Fig. 30D View Fig ). The antennae are inserted at apical ⅓ of rostrum in lateral view (¼ in males). Elytra of females are also more elongate (W: L ratio: 0.70) than in males ( Fig. 30B View Fig ).

Variation

This species varies in color geographically. Populations from the Republic of South Africa have the rostrum, the post-ocular area and the club dark brown while those from west Africa ( Ivory Coast and Senegal) are uniformly pale brown. These variations are not associated with divergent external and internal morphology in specimens examined.

Life history

Adults of this species were collected in various sites on male inflorescences of Phoenix reclinata ( Arecaceae ), which probably constitutes the substrate for the larvae ( Fig. 30H View Fig ). It has been sporadically collected on flowers of Buddleja auriculata Benth. ( Scrophulariaceae ). Adults are attracted by UV lights. This species is the most abundant among those found on male flowers of P. reclinata , at least in the Republic of South Africa. Adults were collected all year round.

Distribution

In our current knowledge, this species is known from Angola, Comoros and La Reunion Islands, Ivory Coast, Kenya, Mozambique, the Republic of South Africa, Senegal, USA ( Florida) and Zimbabwe, but its host is widely distributed in eastern and western Africa, and it is likely that this species is more widespread. In La Reunion Island, this species has only been collected since 2010, suggesting a rather recent introduction on this island (E. Lemagnen pers. com.). This species has also been introduced to North America in recent years.

Remarks

Derelomus costiger was described based on a series of 6 male and 3 female specimens without designation of a holotype ( Marshall 1958). In the collection housed at NHMUK, the type series from Stellenbosch was located. A male of this series bearing a red type label is designated as the lectotype for Derelomus costiger Marshall, 1958 [here designated] and was relabelled accordingly. The rest of the series was labelled as paralectotypes. Psilocaulus elatus Richard, 1958 is a derelomine weevil described from Comoros Islands a few months after Marshall’s description of D. costiger . The examination of the holotype of this species revealed no difference with the lectotype and paralectotypes of D. costiger . As a result, the species name Psilocaulus elatus Richard, 1958 is proposed as a junior synonym of Derelomus costiger Marshall, 1958 [new synonymy].