Helophorus (Ropalohelophorus) aethiops J. Balfour-Browne, 1954

Bilton, David T., 2023, Out of the Palaearctic: the Helophorus water beetles of the Afrotropical Region (Coleoptera: Helophoridae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 63 (2), pp. 249-264 : 253-255

Helophorus (Ropalohelophorus) aethiops J. Balfour-Browne, 1954

( Figs 1B–C , 2C–F , 3B , 4A, C, E, G , 5 )

Helophorus aethiops J. Balfour-Browne, 1954: 105 .

Type locality. South Africa, Eastern Cape Province, Albany District, Gowie’s Kloof, Makhanda (formerly Grahamstown), 33°18′58.71″S 26°31′29.68″E, 570 m.

Type material. HOLOTYPE: J, labelled: “J” “Type” [circular label with red margin] “ SOUTH AFRICA // Albany Dist. // Gowies Kloof // 6.viii.39.” “ J. Omer Cooper // coll.” “ Helophorus (s.str.) // aethiops Type!/ J. Balfour-Browne det.” [genus and species name and Type!Hw.] ( BMNH) . PARATYPES: 2 ♀♀, same data as holotype; 2 JJ, “ SOUTH AFRICA // Albany Dist. // Grahamstown. // v. 1939.” “J. Omer Cooper // coll.” “Brit. Mus. // 1939–625.”; 2 JJ, “ SOUTH AFRICA // Grahamstown. // Teafontein Farm // 29.vii.1939.” “J. Omer Cooper // coll.” “Brit. Mus. // 1939–625.”; 1 J, “ SOUTH AFRICA // Albany Dist. // Piggot Bridge // Rd. 10.ii.39.” “J. Omer Cooper // coll.” “Brit. Mus. // 1939–625.”; 1 J, “ SOUTH AFRICA // Albany Dist. // Piggot Bridge // Rd. 20.iii.39.” “J. Omer Cooper // coll.” “Brit. Mus. // 1939–625.” “ Helophorus (s.str.) // aethiops Paratype!/ J. Balfour-Browne det.” [genus and species name and Paratype! Hw.]; 2 JJ, “ SOUTH-WEST AFRICA. // Windhoek, Avis Dam. // 7.vii.37. // J. Omer-Cooper.” “J. Omer Cooper // coll.” “Brit. Mus. // 1939–625.” All BMNH and with circular Paratype labels with yellow border.

Other material examined. 24 JJ 21 ♀♀, “ 29/xii/2013 South Africa KZN // Temp. pond in grassland beside // R56 road ca. 25 km ENE of // Kokstad D T Bilton leg.” ( AMG, CBP, ISAM, MNHN, NMPC, NMW); 1 J, “ 29/xii/2013 South Africa KZN // Temp. pond in grassland beside // R56 road ca. 25 km ENE of // Kokstad D T Bilton leg.” “DNA voucher // IBE-DV277” ( CBP); 1♀, “ 29/xii/2013 South Africa KZN // Temp. pond in grassland beside // R56 road ca. 25 km ENE of // Kokstad D T Bilton leg.” “DNA voucher // IBE-DV278” ( CBP); 7 JJ 14 ♀♀, “Stn, No. // 111” “S. AFRICA: // Matatiele // 4800ft., 28.iii.1954 ” “Shallow, muddy // roadside ditch // very weedy, // grasses and Juncus” “J. Balfour-Browne // Brit. Mus. 1954–797” ( BMNH); 2 ♀♀, “Stn. No. // 134” “S. AFRICA: // Farm Dam, 4250ft., // nr. Mooi River, // 2.iv.1954 ” “Mud with Juncus // and Nitella” “J. Balfour-Browne // Brit. Mus. 1954–797” ( BMNH); 1 J, “Stn. No. // 84” “S. AFRICA: // E. Cape Province // van Staaden’s Pass, // 21.iii.1954 ” “In gravel at edge // of fast stream” “J. Balfour-Browne // Brit. Mus. 1954–797” “ Helophorus (s. str.) aethiops J. B-B // J. Balfour-Browne det. // v. 1975 ” ( BMNH); 1 ♀, “Stn. No. // 160” “S. SAFRICA: // O.F.S., nr. // Harrismith, // 5500ft., 7.iv.1954 ” “Farm dam, // very grassy.” “J. Balfour-Browne // Brit. Mus. 1954–797” ( BMNH); 2 JJ, 8 exx., “S. AFRICA:// Riversdale Dist. // nr.Albertinia // 16.ii/1947 // J. Omer-Cooper” “Brit. Mus. // 1978-162” ( BMNH); 1 J 1 ♀, “S. AFRICA: // ca. 12 mi. from Queenstown // on road to Lady Frere, // ca. 3800ft., 26.iii.1954 ” “in small // grassy dam” “J. Balfour- -Browne // Brit. Mus. 1954–797” ( BMNH); 1 J 4 ♀♀, “TRANSVAAL // Middleburg Dist. // Middleburg // 29.xi.1948 ” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 2 JJ, 5 exx., “Dry stream // with pools” “TRANSVAAL // Waterburg Dist. // Potgietersrust. //? Matini R. // 25.xi.1948 ” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 2 ♀♀, “TRANSVAAL // Pietersburg Dist. // Bandolier Kop // 23.xi.1948 ” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 3 ♀♀, “TRANSVAAL // Pietersburg Dist. // Dam, 18 mls South // of Pietersburg // 25.xi.1948 ” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 2 JJ, 18 exx., “ ORANGE FREE STATE // Kroonstad Dist. // Vredefort // Nr. Honing Spruit // 29.viii.1947 ” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 1 J, 7 exx., “ CAPE PROV. // Cathcart Dist. // Cathcart // 20.ii.1950 ” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 1 exx., “ CAPE PROV. // Colesburg Dist. // Colesburg. Dam // outside town. // 22.ii.1947 ” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 1 exx., “ CAPE PROV. // Aliwal North Dist.// Dam in mountains // 13.iii.1948 ” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 1 exx., “TRANSVAAL. // Lydenburg Dist. // Belfast. // 30/xi/1948 ” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 2 exx., “ CAPE PROV. // Cathcart Dist. // Cathcart // 20.ii.1950 ” “ SOUTH AFRICA // E. M. Rodgers” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 2 exx., “ CAPE PROV. // Queenstown Dist. // Dam nr. Sterkstroom // 25 mls. Queenstown - // Aliwal. 13.ii.1948.” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 1 exx., “S. W. AFRICA // Okarupa, ca. 17 ml. // E. of Okahandja, // 4900ft. 22.v.1954.” “Pools in overflow // stream from dam, // much weed and algae.” “J. Balfour-Browne // Brit. Mus. 1954–797” ( BMNH); 1 exx., “ CAPE PROV. // Uniondale Dist. // Lange Kloof Mts. // 22.xi.1947 ” [all except CAPE PROV. Hw] “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 1 J, “Stn. No. // 78” [78 Hw.] “S. AFRICA // Witte Elbosch, // Groote River, // 19.iii.1954 ” “Rapid stream, // weeds and moss, // dead edges” “ SOUTH AFRICA // J. Omer-Cooper” “J. Omer-Cooper // B.M. 1981–272” ( BMNH); 1 J, “ Namibia: WINDHOEK // DIST. Krumneck 20 // Farm dam on Oanob R. // SE 2216 Dd // 25.iii.1987 // B.A. Curtis // SMI 3210” “Namibian National // Insect Collection, // National Museum, // OP.O. Box 1203, // Windhoek, Namibia.” ( NMNW); 1 J, “ SOUTH AFRICA: // Aliwal North, // 18-25.viii.1954.” “‘in tank’ // H. Andreae” “ Helophorus // aethiops J. B-B. // J. Balfour-Browne det. // 1975 [name and date Hw] “SAM-COL/ AO 01926” ( ISAM); 2 JJ, 3 exx., “ SOUTH AFRICA: // Aliwal North, // 18-25.viii.1954.” “‘in tank’ // H. Andreae” “ Helophorus // aethiops // Balf.- Browne” [Hw.] “SAM-COL/ AO 01926” ( ISAM); 1 J 3 ♀♀, “ SUDAFRIKA, Natal // 40km S Bethlehem // 30.12.1993 // leg. Wewalka (10)” “1997 // H. aethiops J B-B // R. B. Angus det.” [name and year Hw.] ( NMW); 1 J, “ 9/iii/2018 South Africa EC // Winterberge – seepage // below Fenella Falls // D T Bilton leg.” “DNA specimen // E.E. IBE-AN1090” ( NMW); 1 J, “ 12/iii/2018 South Africa EC // Compassberg, small stream // above farmhouse // D T Bilton leg.” “DNA specimen // E.E. IBE-AN1092” ( NMW); 1 J, “ 11/iii/2018 South Africa EC // Toorberg – temporary pool // 1 km NW of Longfontein // D T Bilton leg.” “DNA specimen // E.E. IBE-AN1095” ( NMW); 1 J, “ SOUTH AFRICA, W. Cape, 4 Sept 2003 // leg. C.R.Turner, 33º39’19”S 21º01’05”E, alt: 310m, // R62 c. 32km east of Ladismith, Large Bridge // with waning river slight flow with silty/fine sand, // rock based pools with sparse vegetation,// some sedges and little reeds.” ( CBP); 1J 2♀♀, “ SOUTH AFRICA, W. Cape, 4 Sept 2003 // leg. C.R.Turner, 33º39’19”S 21º01’05”E, alt: 310m, // R62 c. 32km east of Ladismith, Large Bridge // with waning river slight flow with silty/fine sand, // rock based pools with sparse vegetation, // some sedges and little reeds.” ( CTP).

Redescription. Male ( Fig. 1B ). Head black, with strong purple aeneous reflection; strongly shining. Granules effaced, most reduced to a central seta-bearing pore; more evident laterally on clypeus and immediately in front of Y-groove, where some coalesce into irregular, transverse ridges. Y-groove shallow; floor with dense, coarse, rugose punctures, shining as rest of head; stem evenly diverging anteriorly; lateral branches narrow, straight proximally then weakly arcuate laterally in front of eyes. Clypeus slightly elevated in centre; anterior margin weakly arcuate. Labrum with shining, impunctate, basal portion with anterior margin bisinuous around centre; anterior portion with coarse, rugose punctures, each puncture bearing a short, stout, whitish semi-erect seta; anterior margin arcuate with broad, shallow anteromedian emargination.Antennae 8-segmented, yellowish brown, with cupule and club segments darker. Maxillary palpi yellow, apex of terminal segment infuscated; moderately elongate, terminal segment longest, curved and clearly asymmetrical.

Pronotum ( Figs 3B & 4C, E ) predominantly reddish brown, with strong purple aeneous reflections, particularly on internal intervals; anterior and lateral borders paler, yellowish brown; shining over entire dorsal surface. Broadest between middle and anterior margins; weakly arched in frontal and dorsal views and somewhat flattened over internal intervals, particularly anteriorly. Anterior margin almost straight over central 0.5, then sinuate to broadly rounded front angles; posterior margin broadly bisinuate around centre. Sides straight over posterior 0.4, then weakly arcuate around broadest point to anterior angles. Lateral margins setose and very weakly crenulated to serrate. Internal and middle intervals flat, very weakly to weakly granulate, strongly shining; most granules reduced to pore and seta; granules more evident on external interval, surface strongly shining and somewhat rugose. Grooves smooth and shining, with sparse, shallow punctures and small raised areas but no clear trace of granules. Median groove narrowed anteriorly and posteriorly, open at both ends more widely so posteriorly. Submedian and submarginal grooves broadly open anteriorly and posteriorly. Submedi- an grooves relatively broad, sinuate. Submarginal grooves straight internally, weakly sinuate externally, broader than submedian. Marginal grooves curved parallel to the side of pronotum, width uniform. All grooves relatively shallow, but with sides abrupt and vertical, particularly evident in submedian, submarginal and marginal grooves.

Elytra ( Fig. 1B ) brownish-yellow, with diffuse, irregular infuscation; sometimes coalescing into more or less discrete patches around suture and on disc. Shape elongate oval, bluntly rounded at apex. In lateral profile flat over anterior 0.5, then gradually descending to apex. Puncture rows weakly to moderately striate, particularly laterally; intervals weakly arched, more evident laterally.

Legs yellowish-brown, apex of last tarsal segment and claws infuscated. Swimming hairs distinct and clearly visible.

Venter black, with pronotal hypomeron, antennal pocket and pseudepipleura and epipleura orange-brown to straw yellow. Mentum shining, centre without microreticulation, with sparse, medium punctures; lateral marginal areas with weak isodiametric microreticulation centrally; margins with fine yellow setae, denser towards posterolateral angles. Submentum shining, without microreticulation; anterior half with sparse, shallow, coarse punctures and fine, hair-like vestiture. Gula and genae rugose, with dense hydrofuge vestiture. Gular sutures well marked as pits anteriorly. Vestiture only absent around margin of compound eyes and their posterolateral corners. Prosternum dull, rugose, with dense hydrofuge vestiture and sparse, long, erect setae approximately 2× length of vestiture. Pronotal hypomeron dull, with dense hydrofuge vestiture. Pronotal epipleura shining, glabrous, with sparse shallow punctures. Anterior antennal pocket well developed, with long, dense setae internally and long, curved setae at posterolateral margins. Elytral epipleura dull, glabrous, narrowing posteriorly at level of metaventrite and continuing until posterior margin of ventrite. Elytral flanks very narrowly visible from below. Ventral surface of mesothorax, metathorax and abdomen dull, with dense hydrofuge vestiture and longer, erect setae; longer setae concentrated on centre of metaventrite and abdominal ventrites 2–5; setae on ventrites arising from longitudinal tubercles, which sometimes appear as shining patches. Hind margin of abdominal ventrite 5 weakly crenulate.

Aedeagus ( Fig. 2C ), elongate, 0.5 mm in length. Basal piece equal in length to parameres; outer margins of parameres weakly and evenly arcuate to apex; interior margins of parameres very weakly concave apically. Median lobe with apex weakly pointed; sides diverging posteriorly to base of struts, weakly concave; struts slightly longer than to tube.

Female. Externally as male, but most somewhat larger.

Measurements. Males: Holotype: BL = 3.50 mm; EL = 2.40; EW = 1.40 mm. Males: BL = 2.60–3.60 mm; EL = 1.90–2.45 mm; EW = 1.10–1.45 mm. Females: BL = 3.45–4.20 mm; EL = 2.30–2.70 mm; EW = 1.35–1.70 mm.

Variation. As with most Helophorus from which long series are available, there is some variation in many characters, both within and between populations. In particular, the aeneous reflections on the head and pronotum vary from purplish to greenish, with the background colour of the pronotum varying from pinkish brown to pitchy and the elytral colouration varying from relatively pale to relatively dark (see Figs 1B–C ). The degree of elytral infuscation also varies, from almost absent to dominant over the disc. ( Figs 1B–C ). In some specimens the granulation of the pronotal intervals is more evident than others, but granules, if evident, are always weak and flat. The degree of sculpture visible in the pronotal grooves also varies somewhat, this being correlated with the degree of interval granulation evident, but grooves are always as described above in terms of their relative widths, and their abrupt, vertical margins. In the aedeagus, there is variation in the size (0.50–0.55 mm) and in the shape of paramere apices between specimens, this variation being seen within populations when longer series are available ( Figs 2C–F ). In some specimens the paramere apices appear pointed, as in the holotype; in others they are internally produced. The basal piece varies from being equal to or slightly longer than the parameres and on the median lobe the struts vary from being equal to or slightly longer than the tube.

Differential diagnosis. This species can be distinguished by its 8-segmented antennae, a pronotum with relatively weak granulation but relatively broad, sharply-defined grooves, relatively large serial punctures on the elytra, with narrow intervals and features of the aedeagus, including the shape of the paramere apices and relatively small size. Distribution and ecology. Apparently widely distributed in summer and year-round rainfall regions of South Africa, extending along the Great Escarpment into Namibia ( Fig. 5 ). Gaps between known South African and Namibian records likely reflect lack of collecting rather than genuine absences. In the southwest extends as far west as the Riversdale district in the Western Cape Province. Not to date known to overlap geographically with H. brumopluvialis sp. nov. Most collections are from the austral summer, but some are from other months in areas of year-round rainfall. Characteristic of shallow, seasonally flooded waters, typically with aquatic grasses, algae and macrophytes. Cytochrome oxidase-I DNA sequence divergence between this species and H. brumopluvialis sp. nov. is 5.5–6.0% (I. Ribera, pers. comm.), suggesting that these two species diverged during the Plio-Pleistocene.

Figures

Fig. 1. Afrotropical Helophorus, habitus. A – H. aethiopicus Régimbart, 1907, lectotype; B – H. aethiops J. Balfour-Browne, 1954, holotype; C – H. aethiops J. Balfour-Browne, 1954, Kokstad, South Africa; D – H. cooperi Orchymont, 1947, holotype; E – H. brumopluvialis sp. nov., holotype; F – H. nyandaruaensis sp. nov., holotype; G – H. simiensis sp. nov., holotype. Scale bar = 1 mm.

Fig. 2. Afrotropical Helophorus, aedeagi. A – H. aethiopicus Régimbart, 1907, lectotype; B – H. aethiopicus, paralectotype; C – H. aethiops J. Balfour-Browne, 1954, holotype; D–F – H. aethiops J. Balfour-Browne, 1954, Kokstad, South Africa; G – H. cooperi Orchymont, 1947, holotype; H – H. brumopluvialis sp. nov., holotype; I–J – H. brumopluvialis sp. nov., Hopefield, South Africa; K – H. nyandaruaensis sp. nov., holotype; L – H. simiensis sp. nov., holotype. Scale bar = 100 μm.

Fig. 3. Afrotropical Helophorus, pronota.A – H. aethiopicus Régimbart, 1907, lectotype; B – H.aethiops J. Balfour-Browne, 1954, holotype; C – H. cooperi Orchymont, 1947, holotype; D – H. brumopluvialis sp. nov., holotype; E – H. nyandaruaensis sp. nov., holotype; F – H. simiensis sp. nov., holotype.

Fig. 4. SouthAfrican Helophorus, SEMs.A, C, E & G – H. aethiops J. Balfour-Browne, 1954, Kokstad, South Africa; B, D, F & H – H. brumopluvialis sp. nov., Hopefield, South Africa.A–B – head detail; C–D – pronota; E–F – pronotal detail, median groove to far left; G–H – left elytral striation close to apex.

Fig. 5. Afrotropical Helophorus, known distributions.Map by https:// mapswire.com.