Heptamelus ochroleucus ( Stephens, 1835 )

Vikberg, Veli & Liston, Andrew D., 2009, Taxonomy and biology of European Heptamelini (Hymenoptera, Tenthredinidae, Selandriinae), Zootaxa 2112, pp. 1-24 : 9-15

Heptamelus ochroleucus ( Stephens, 1835)

Melicerta ochroleucus Stephens, 1835: 94 –95. Holotype by monotypy (implicit in mention of damage to antennae of type specimen in the description of Melicerta ), sex not stated, type locality: Devonshire ( England).

Heptamelus ochroleucus (Stephens) : Haliday, 1855: 60.

Heptamelus (Heptamelus) ochroleucus: Zhelochovtsev, 1988: 176 .

Coenoneura Dahlbomi : Cameron 1873: 85, misidentification (“My specimen [female] is the variety described by Thomson, with antennae entirely black..”).

Notes on original descriptions and type material. The holotype of Melicerta ochroleucus Stephens, 1835 is considered to be lost, as explained below. The original description of M. ochroleucus reads ( Stephens 1835: 95):

Yellowish-white: head deep shining black; labrum and antennae ochreous; thorax with 2 abbreviated fuscous streaks in front, and 2 deep black streaks on the sides beneath the wings; abdomen paler than the thorax, the base of each segment, excepting the terminal one, with a broad fuscous fascia; legs entirely pale ochreous-white; wings hyaline, pale ochreous, with the nervures and stigma yellowish. Taken in Devonshire, apparently rare, I believe in June.” Possibly significant, is that Stephens states that both antennae of the single specimen on which he based his description were broken, only antennomeres 1 –6 remaining.

Cameron (1877), Kirby (1882) and Konow (1897) all commented on the discrepancies between the description by Stephens (1835) of Melicerta ochroleucus and that of Haliday (1855) of Heptamelus ochroleucus (Stephens) . Kirby (1882: 195, footnote) writes: “The Stephensian specimen representing this species in the British Collection is Strongylogaster eborina, Klug [= Stromboceros delicatulus (Fallén, 1808) ] (cf. Cam. Ent. M. M. xiii. p. 175), which differs both generically and specifically from the descriptions of Stephens and Haliday; and Stephens says that the antennae were broken in his specimen, whereas they are perfect, or nearly so, in the above-mentioned specimen of S. eborina .” Cameron (1877) had already published essentially similar conclusions, after a study of material in the Stephens Collection, deposited in BMNH.

G. Broad (pers. comm.) informs us that at BMNH there is no mention in the collection or archive (indexes, catalogue, etc.) of a type specimen of Melicerta ochroleuca , or any other combination of the name. There are no Stephens’ specimens standing under that name, but five Stephens’ specimens stand under Stromboceros delicatulus . The only information on these specimens is that each has a typed accession label ‘Stephens Coll. 53–46’ and a hand-written small label ‘ delicatulus’. There are four females and one male. The male has intact antennae, black anteriorally on the three mesoscutal lobes and mostly black 7th–8th terga. Of the females, three have intact antennae and pale mesoscutal mid-lobes, but one has both antennae broken off after antennomere 6. This specimen was examined by AL and found to be a morphologically typical specimen of S. delicatulus (see Table 1 ). Extent of the dark colouration in S. delicatulus varies; this specimen has all three mesoscutal lobes dark marked and the terga are not black, but brown, paler medially, darker apically. This disagrees with the colour pattern described by Stephens. We agree with Kirby (1882), that a specimen of Stromboceros delicatulus (Fallén, 1808) can not have been the holotype of Melicerta ochroleucus . In particular, the relative lengths of antennomeres given by Stephens do not fit S. delicatulus ( Table 1 ).

Konow (1897) discusses at some length the discrepancies between the Stephens’ descriptions of Melicerta and M. ochroleucus on the one hand and the species then known as Heptamelus ochroleucus on the other. He reaches the conclusion, although apparently without having studied the type specimen, that Stephens unknowingly based his description on the body of a Harpiphorus lepidus (Klug, 1818) specimen to which had been glued the head of a Stromboceros delicatulus . However, such a calamity would still not have provided Stephens with the characters which he describes for M. ochroleucus , because in S. delicatulus the clypeus is emarginate and the relative lengths of the antennomeres of S. delicatulus correspond even less well with the description by Stephens than do those of Heptamelus ( Table 1 ). Finally, Konow concluded that Melicerta ochroleucus Stephens, 1835 was to be regarded as a species inquirenda and that authorship of the name ochroleucus should be attributed to Haliday (1855), because Haliday’s description, only of the male sex, unequivocally refers to the species known as H. ochroleucus . Adoption of this nomenclatural solution is unfortunately not allowable, although followed by numerous subsequent authors, because Haliday was convinced that he was re-describing Stephens’ species and therefore did not make a separate species-group name available for this taxon.

The characters of diagnostic importance in the description of Melicerta ochroleucus by Stephens (1835) are listed in Table 1 and compared with those of Stromboceros delicatulus (Fallén, 1808) and the male of the species currently called Heptamelus ochroleucus . In part, the difficulty that earlier authors had in recognizing Stephen’s description as applying to this taxon, may have been the result of the male being unknown to them. On the other hand, Haliday seems to have only seen males and therefore had no reservations in placing his material as conspecific with M. ochroleucus . We conclude that the Stephens’ descriptions fit our present understanding of H. ochroleucus in all respects, except for the shape of the clypeus. Considering the probably poor quality of optical equipment available to Stephens and small size of the clypeus in Heptamelus , such an error is easy to imagine. A similar mistake might even explain the “broken” antennae of Stephens’ holotype, when two facts are considered. Firstly, at Stephens’ time no Tenthredinidae were known with less than 7 flagellomeres. Since the works of Linnaeus, a flagellum with 7 articles had been accepted as the most common character state in sawflies: numerous taxa with a greater number of flagellomeres were known, but none with fewer until Haliday (1855) described Heptamelus . Secondly, the apical antennomeres of H. ochroleucus are rather hard to differentiate. Stephens may therefore have had a specimen with intact antennae, but overlooked the division between the last two of these, and because of a preconception, failed to realise that the reduced number of antennomeres was natural.

The doubts expressed by previous authors as to the identity of Melicerta ochroleucus Stephens, 1835 make it necessary to fix its identity by designation of a neotype. Females of Heptamelus possess a larger number and more obvious diagnostic characters than males, and males do not occur in all species. Accordingly, a female specimen is selected as neotype, although Stephens apparently described a male:

Neotype of Melicerta ochroleucus Stephens, 1835 (here designated): female, Norfolk, Catfield, TG 379201, Malaise trap, abandoned wet meadow, 19.– 26.8.1984, leg. R. T. J. Jarvis ( RSME).

Re-description [ Figs 8–15 ]. (see key above and the following supplementary notes)

Body length: female 4.8–5.4 mm (n = 3 females from Finland), male 3.6–5.2 (n = 37 males from Finland).

Clypeus convex (i.e. with lateral edge deflected towards posterior: view from side!), front margin with pronounced, arcuate medial emargination ( Fig. 14 ). Upper half of mesepisternum usually with several large, deep punctures, interspersed with smaller, shallower punctures of only about half diameter of the large ones. Lancet ( Figs 12, 13 ): 12 annuli; denticles occupy almost entire length of medial annulus.

Colour: Female. Black. Palps and labrum pale whitish. Mandibles red-brown. Antenna entirely black. Thorax with upper edge of pronotum usually pale marked, often also with brown markings on mesonotum and mesepisternum. Mesopleuron always with at least thin, pale stripe along upper part of mesopleural groove. Legs entirely pale except for more or less slightly infuscate apex of hind tibia. Stigma of forewing with disc pale brown, anterior edge even paler (best seen in fresh specimens); costa whitish; rest of venation largely blackish; wing membrane slightly infuscate. Abdominal sterna always extensively pale, sometimes also with pale markings on central parts of terga.

Melicerta ochroleucus Stephens, 1835 Stromboceros delicatulus (Fallén, 1808) Heptamelus ochroleucus male. Male. Head black; palps, mandibles and labrum more or less pale; antenna largely pale. Thorax and abdomen extensively pale yellow-brown with highly variable black markings. In darker specimens black markings on mesepimeron and mesepisternum still always separated by at least narrow, pale stripe along mesopleural groove. Wing: venation including costa and stigma pale; membrane hyaline, tinged yellow.

Variability. 7 or 8 antennomeres. Number and size of punctures on mesepisternum varies considerably.

Female: pale markings may be absent or more or less developed on the inner part of lateral mesoscutal lobe, metepisternum, metepimeron, centre of mesepisternum, lateral and central parts of abdominal terga. Palest specimens are from Sweden, with nearly entirely pale lateral mesonotal lobes and lower half of mesepisternum. Darkest specimens studied are from Brandenburg, in which even margins of pronotum are dark.

Male: entire antenna pale, or flagellum more or less infuscate apically. Clypeus entirely dark, or extensively pale. Body colour highly variable: thorax and abdomen entirely yellow-brown, through all types of intermediates, to extensively black-marked on thoracic sterna (dorsal parts of mesepisternum and mesepimeron), more or less metanotum, and terga of abdomen.

Comments. See key to adults above for distinction from H. dahlbomi . The descriptions of Heptamelus species from the East Palaearctic include combinations of characters which do not occur in H. ochroleucus . In particular, the punctation of the mesepisternum in most of these is described as fine and shallow, thus resembling H. dahlbomi . The characterization of H. ochroleucus (Stephens) based on Japanese specimens by Togashi (1961), agrees quite well with darker European males, but several of the characters described for the female (colour pattern, lancet with 13 annuli, distribution of denticles) do not fit European specimens. Four males from Japan standing under the name H. ochroleucus in BMNH were examined: Japan, Honshu, Kyoto, Kurama, 2ɗ 19.v.1940. Pres. by K. Takeuchi. BM 1952–351; 1ɗ, same data as last, except Kibune [instead of Kurama], 4.5.1937, Heptamelus ? ochroleucus det. Takeuchi; Tsunagi, near Kanazawa, 1ɗ 3.5.1955, leg. I. Togashi, Heptamelus ? ochroleucus det.Togashi. They resemble European H. ochroleucus males in many details of morphology, but differ in greater body length (5–7 mm), dark anterior margin of otherwise pale forewing stigma and a more shallowly emarginate clypeus. It seems probable that these are not conspecific with H. ochroleucus , but they must remain unidentified until a much needed revision of East Palaearctic species, including the problematic association of sexes, is undertaken.

H. japonicus Togashi, 1961 (only male known) is said to differ from H. ochroleucus by Togashi (1961), mainly in the morphology of the head (form of clypeus, size of eyes and position of the postocellar furrows) and different form of penisvalve and harpes. The attitude of the longer setae at the apex of the harpes varies widely in European H. ochroleucus . In some specimens these are directed posteriorally, in others towards the anterior. Probably the apparent differences are caused by disturbance of the setae or distortion of the harpe during drying. The character seems to be of dubious value. The very pale body colour considered by Togashi to be characteristic of H. japonicus is not uncommon in very variably coloured European H. ochroleucus males. However, H. japonicus is probably distinct from H. ochroleucus . 1 male from Japan identified as H. japonicus was examined; Senami, 9.VI.1963, labelled Heptamelus japonicus Togashi , coll. Eitel Lindqvist (MZH). Body 5.0 mm, head width 1.27 mm, clypeus 0.47 x 0.22 mm, apical emargination rounded,with lateral teeth broad and rounded. Clypeus 2.1 times as wide as long. Compared with a male H. ochroleucus from Kitee, Finland: head width 1.06 mm, clypeus 0.37 x 0.14 mm or 2.6 times as wide as long, apical emargination rounded, deeper, with lateral teeth sharper, narrower.

Sex ratio. Females / males: approximately 1.0: 1.4 (all specimens examined, n = 108). Noteworthy is however the abundance of males in Finnish material: 1.0: 11.0 (n = 48). Excluding the Finnish material, a ratio of approximately 2:1 results.

Hostplants. Unknown. Various genera of ferns are given in the literature as hosts in Europe of Heptamelus ochroleucus : Athyrium filix-femina (L.) Roth ( Woodsiaceae ) (de Meijere 1911; Benson 1952), Blechnum spicant (L.) Roth ( Blechnaceae ) ( Benson 1952), Dryopteris dilatata (Hoffm.) A. Gray (Dryopteridaceae) ( Shaw & Bailey 1991), Matteucia struthiopteris (L.) Tod. ( Woodsiaceae ) ( Lorenz & Kraus 1957), Polypodium vulgare L. ( Polypodiaceae ). No reared voucher specimens from these hosts were examined, so they might refer to either H. ochroleucus or H. dahlbomi . Naito (1979) recorded Polystichum rectrorsopaleaceum (misspelt rectroso-paleacum) (Kodama) Tagawa ( Dryopteridaceae ) as a host of H. ochroleucus in Japan.

Distribution. Europe: Belgium ( Magis 2005, male recorded), England, Finland, France ( Chevin 2005, male recorded), Germany, Ireland ( Haliday 1855, males recorded), Italy ( Zombori 1984, males recorded), Norway, Poland, Scotland, Sweden, Switzerland and Wales. Mainly montane in the South.

Confirmed records are only from Europe: identity of specimens recorded from Japan as H. ochroleucus by Togashi (1961) and Naito (1982, with data on karyotype) is uncertain (see above).

Material examined. Unless otherwise stated det. A. Liston and Finnish specimens det. V. Vikberg:

England: Cheshire: Abbott’s Moss, SJ5865, 1Ψ, 24.6.1991, leg. C. Clee, det. G. Knight (WML).

Norfolk: Catfield, TG 379201, Malaise trap, abandoned wet meadow, 1Ψ, 19.– 26.8.1984, leg. R. T. J. Jarvis (Neotype, RSME).

North Yorkshire: Lastingham, 1ɗ, Marshall Coll., BM 1904-120 ( BMNH).

British Isles (?): 2Ψ and 2ɗ, without data, ex Cameron and Marshall Collections ( BMNH), 1ɗ, leg. Cameron ( RSME).

Finland: V [= Varsinais-Suomi]: Vihtijärvi, 3ɗ, 29.6.1963, leg. R. Tuomikoski (VVT).

U [= Uusimaa]: H fors [Helsingfors = Helsinki], 1ɗ, 5.viii. [18]49; leg. W. Nylander ( Forsius 1933; MZH). Pernå [= Pernaja], 1ɗ, 12.7.1944; 1ɗ, 12.7.1945, leg. Å. Nordström (MZH). Tvärminne, 1ɗ [abdomen missing], leg. [E. W.] Suomalainen ( Forsius 1920: 218-219; MZH).

EH [= South Häme]: Janakkala, Hangastenmäki, [Grid 27°E] 6755:3369, 1Ψ, 8.7.2000, leg. V. Vikberg (VVT).

ES [= South Savo]: Kerimäki, 575 [= Mäkrä], 2Ψ [1 without head], 5.7.1945; 1ɗ, 5.7.1945, leg. J. Kangas (ZMH). Kerimäki, 19ɗ, 6.7.1945, leg. E. Kangas (ZMH). Kerimäki, [577 = Patasalo], 9ɗ, 6.7.1945, leg. J. Kangas (ZMH). Kerimäki, 3ɗ, 6.7.1945, leg. Y. Kangas (ZMH). Kerimäki (577), 1Ψ 1ɗ, 6.7.1945, leg. J. Kangas (MVH); Kerimäki, 2ɗ, 6.7.1945, leg. E. Kangas (MVH).

LK [= Ladoga Karelia]: Parikkala, 1ɗ, 4445 [white = moist forest near shooting range, 16.7.1945], leg. [W.] Hellén (MZH).

PK [= North Karelia]: Kitee, 1ɗ, 30.6.1963, leg. V. Vikberg (VVT).

Germany: Baden-Württemberg: Tonbachtal, 1Ψ, 21.vi.1990, leg. E. Jansen (EJAC).

Bavaria: Nationalpark Bayerischer Wald, Malaise traps, 28.vi.–19.vii.2007, leg. G. Merkel-Wallner; 1Ψ T4_0 9, 49.0 9732°N 13.21018°E (715 m) (ZSM); 1Ψ, T2_41, 48.95606°N 13.37968°E (987 m), 28.vi.–19.vii.2007; 1Ψ T2_49, 48.96293°N 13.38392°E (1060 m) (ZSM); 1ɗ T4_64 49.10256°N 13.28506°E (1137 m) (ZSM); 1Ψ T4_77, 49.10379°N 13.30277°E (1284 m) (ZSM); 1ɗ T1_63 48.96175°N 13.38 E (1287 m) (ZSM); 1Ψ T4_81, 49.10341°N 13.29732°E (1319 m) (USNM); 1Ψ 1ɗ T1_66 48.96396°N 13.44919°E (1368 m) (ZSM / USNM). NP Bayerischer Wald, Freyung, Malaise Falle; Simandlruck 2 1120m, R4609561 h5423224, 6Ψ, 6.6.– 20.6.2000, leg. I. Kuhlmann (MKN); Waldhaus Reibe 1100m, Bergfichtenwald Käferloch r4509100 h5422700, 1Ψ, 17.6.– 6.7.2003, leg. I. Kuhlmann (MKN); Feistenhang 8 875m, r4601751 h5424364, 1Ψ, 9.9.1998, leg. I. Kuhlmann (MKN). Brandenburg: Angermünde, Luisenfelde, Langer Berg, Malaisefalle M4a, 1Ψ, 12.6.1996, leg. DEI (DEI). Eberswalde-Golzow, nördl. Golzow, Malaisefalle M5, 1Ψ, 27.5.1993, leg. M. Sommer (DEI).

Nordrhein-Westfalen: Neunkirchen-Seelscheid, Wahnbachtal, 1Ψ, 04.vii.1989, leg. K. Mohr (EJAC).

Saxony: Erzgebirge, Umg. Altenberg, 1ɗ, 22.7.1985, 1Ψ, 8.7.1986, leg. S. Walter (DEI).

Norway: Eidfjord, Tveit, Simadalen, 32VMN006086, 3Ψ, 8.v.–3.ix.2005, Malaise trap, leg. E. Rindal & T. Darup, det. O. J. Lønnve (NHMO). Halden, Nokkedal, sjø, 32VPL3685452453, 1Ψ, 29.v.–4.vii.2008, Malaise trap, leg. et det. O. J. Lønnve (NHMO).

Poland: Poolasie, Bialowieza, 1ɗ, 7.7.1988, leg. M. Koponen (ZMH), det. V. Vikberg.

Scotland: Edinburgh: Currie Village, 1Ψ, 20.7. [19]35, leg. R. W. W. (BMNH). Corstorphine Hill, 1Ψ, 22.6.1981, leg. A. D. Liston (RSME).

Fife: Markinch, Star Moss, 1ɗ, 1.6.1980, leg. E. C. Pelham-Clinton (RSME).

Dumbartons.: Caldarvan, NS 450836, Malaise trap, mixed wood by pond, 3Ψ 7– 18.7.1983; 1ɗ, 1– 17.8.1983; 1Ψ, 27.6.– 7.7.1983, leg. I. C. Christie (RSME).

Strathclyde: Johnstone, 1Ψ, 24.7.1918; 1Ψ, 27.7.1918 (RSME). Cadder, 1Ψ, leg. Cameron (BMNH). South of Clyde, 1Ψ, leg. Cameron (BMNH). Bonhill, 1ɗ, 17.7.[19] 0 7, ex Harwood Collection (BMNH). Bonhill, 1Ψ, 17.7.[19] 0 7, leg. J. R. Malloch (RSME).

Argyll: Port Appin, Clach Thall, 1ɗ, 5.9.1954, leg. E. C. Pelham-Clinton (RSME). Aberdeens.: Ordie, Loch Davan, 2ɗ, 23.7.1970, leg. E. C. Pelham-Clinton (RSME).

Inverness.: Loch Garten, Malaise Trap, 1Ψ, June 1981, leg. J. A. Owen (RSME).

Sweden: Scania: Rsiö [printed label, = Ringsjön, see Fitton 1982], 1Ψ, leg. Thomson [printed label “Ths”], “ Dahlbomi ” [handwritten label, probably by Thomson] (MZLU).

Sc. [=Scania], 1Ψ (MZLU). Kullaberg, Josefinelust, 1Ψ, 2.7.1953, leg. Bo Tjeder (MZLU). Kullaberg, 1Ψ, 17.7.1960, leg. Benander (MZLU).

Halland: Knäred Krokån, Körsveka, 1ɗ, 14.vii.1967, leg. Bo Tjeder (MZLU).

Switzerland: Ticino: Alpi di Neggia, Tamaretto (1400–1700 m), 1ɗ, 04.vii.1996, leg. E. Jansen (EJAC).

Wales: Caernarvon: Cors Graianog, SH502452, 1ɗ, 23.5.2007, flying near large stand of Athyrium filixfemina , leg. et det. G. T. Knight (WML).

Cardigan: Cors Llynn Rarch, a Llyn Fanod SN599638, 1ɗ, 23.7.1987, leg. P. Holmes (RSME).

Figures

FIGURES 8 – 14. Heptamelus ochroleucus (Stephens), Ψ (Germany, Bavarian Forest National Park). 8, lateral; 9, head, dorsal; 10, sawsheath, lateral; 11, sawsheath, dorsal; 12, lancet, apex; 13, lancet; 14, clypeus. Scale bars = 0.5 mm.

FIGURES 15 – 19. 15, H. ochroleucus, ♂ (Germany, Bavarian Forest National Park), lateral; 16 – 17, Pseudoheptamelus runari Conde (Finland, South Häme, Janakkala, Hangastenmäki, leg. VV). 16, Ψ, dorsal; 17, sawsheath, lateral. 18 – 19. 18 – 19, Larva of H. dahlbomi (Finland, Hangastenmäki). 18, immature larva, anterior, lateral; 19, last feeding larval instar, lateral. Scale bars = 0.5 mm.

Tables

TABLE 1. Comparison of characters of diagnostic significance in: 1, the original descriptions of Melicerta Stephens, 1835 and M. ochroleucus Stephens, 1835; 2, the female Stromboceros delicatulus specimen with damaged antennae ex Stephens Collection; 3, male of Heptamelus ochroleucus. Only the male of H. ochroleucus is included in this comparison, because the colour characters described by Stephens preclude the possibility that his description was based on a female of a European Heptamelus species.

Scape and pedicel short. [This is too imprecise to be weighted highly. Possibly only “short” relative to following flagellomeres]	Scape short, only slightly longer than wide. Pedicel approx. 1.5x as long as broad.	Scape and pedicel long, approx. 2x as long as wide.
Antennomere 3 linear.	Antennomere 3 very slightly widened apically.	Antennomere 3 slightly widened apically.
Antennomere 3 nearly as long again as 4.	Antennomere 3 only slightly longer than 4.	Antennomere 3 approx. 2x as long as 4.
Antennomeres 5 and 6 nearly equal in length, slightly shorter than 4.	Antennomeres 5 and 6 nearly equal in length, but together only ca. as long as 4.	Antennomeres 5 and 6 nearly equal in length, slightly shorter than 4.
Clypeus not emarginate.	Clypeus with small but clear emargination.	Clypeus deeply emarginate.
Head slightly produced in front between the eyes.	Head slightly produced in front (frontal ridge and antennal crests).	Head slightly produced in front (whole frontal area, evenly)
3 submarginal cells in forewing.	4 submarginal cells in forewing.	Often apparently 3 submarginal cells in forewing through regularly occurring obsolescence of Rs.
Wings shortish.	Wing length normal.	Wing length normal.
Yellowish white.	Yellowish-white.	Variable: Yellowish-white to pale brown.
Head black. Antennae and labrum ochreous.	Head black. Antennae, labrum and clypeus pale.	Head black. Antennae and labrum pale. Clypeus at least partly pale.
Thorax with 2 abbreviated fuscous streaks in front.	Mesoscutum with 3 fuscous markings (one on each lobe).	At most medial mesoscutal lobe with undivided central black area.
Base of each abdominal tergum except last with broad fuscous fascia.	Only terga 1 and 4–8 with fuscous markings.	Highly variable, but specimens occur with this colour pattern.