Corresponding author: Kurt Jordaens (
Academic editor: Ximo Mengual
The Afrotropical representatives of the hover fly genus
Jordaens K, Goergen G, Skevington JH, Kelso S, De Meyer M (2021) Revision of the Afrotropical species of the hover fly genus
Over the last two decades, there has been an increased activity on the taxonomy and systematics of Afrotropical hover flies (also called flower flies) (
The genus
The taxonomy of the Afrotropical species of
Several species show strong sexual dimorphism with males exhibiting long pile on the legs and modified metafemora with grooves and excavations (e.g. Figs
Specimens from the following institutional and private collections were studied:
Part of the material has been collected by the authors between 1994 and 2018. Mostly, hover flies were collected from agricultural land and its adjacent environment. Private grounds were never accessed without prior consent by the owners and were visited with national recruited staff and as part of the ongoing projects on pest control and biodiversity of the institutions.
Morphological terminology follows
Procedures for DNA barcoding followed
For the molecular analysis, we obtained 159 DNA barcodes which were submitted to GenBank under accession numbers
A Neighbour-Joining (
Afrotropical species of
Note: the males of
1 | Profemur with long, downwardly curved pile in distal half which is at least 1.4× as long as femur width (referred to hereafter as “apical pile brush”) (Figs |
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– | Profemur lacking apical pile brush, pile less than 1.4× as long as femur width (Figs |
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2 | Probasitarsus with tuft of black pile (Figs |
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– | Probasitarsus either without tuft of pile (Fig. |
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3 | Profemur with apical pile brush dark brown; protibia strongly flattened and with long black pile in proximal half and long yellow-orange pile in distal half; probasitarsus without tuft of orange pile (Fig. |
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– | Profemur with apical pile brush black (Figs |
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4 | Profemur with apical pile brush entirely black, no yellow setae interspersed (Fig. |
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– | Profemur with apical pile brush black with some short yellow pile interspersed (Fig. |
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5 | Profemur with apical pile brush very dense (individual pili difficult to discern) (Figs |
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– | Profemur, apical pile brush loose (individual pili easy to discern) (Figs |
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6 | Profemur with apical pile brush golden yellow to orange (Fig. |
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– | Profemur with apical pile brush black dorsally (Figs |
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7 | Protarsus orange (Fig. |
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– | Probasitarsus black in anterior half, orange in posterior half, protarsi 2–4 black, protarsus 5 lighter with darkened tips (Fig. |
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8 | Profemur with apical pile brush entirely black (Fig. |
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– | Profemur with apical pile brush either yellowish with some black pile interspersed (Fig. |
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9 | Profemur with apical pile brush yellowish with some long black pile interspersed (Fig. |
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– | Profemur with apical pile brush black dorsally, yellow ventrally (Fig. |
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10 | Face with ground colour black (Figs |
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– | Face with ground colour white to yellow, with black medial vitta (e.g. Figs |
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11 | Metafemur with dense, thick black pile on proximal 1/5 (Fig. |
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– | Metafemur without dense, thick black pile on proximal 1/5; scutum not vittate, sometimes with a pair of very faint vittae; tergite II with a pair of large, more or less rectangular orange maculae; tergite III either similar as tergite II or entirely orange (Fig. |
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(Note: we suspect that the male of |
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12 | Probasitarsus whitish to orange, with a lateral lobe bearing an orange pile tuft (Fig. |
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– | Probasitarsus orange, brown or black, but never with a lateral lobe and never with an orange pile tuft; profemur either dorsally flattened (Fig. |
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13 | Metafemur with anteroventral proximal 1/4 bare and posteroventral proximal 1/4 with thick yellow (Fig. |
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– | Metafemur with anteroventral proximal 1/4 pilose; mesotibia either entirely black pilose or yellow and black pilose (Figs |
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14 | Metatibia ventrally with a tooth-like projection on the distal end (Fig. |
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– | Metatibia ventrally without a tooth-like projection on the distal end and metafemur predominantly yellow pilose in the posteroventral proximal part (Fig. |
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15 | Mesotibia proximal 2/3 dorsally with long, curved yellow pile; distal 1/3 with short black pile on ventrolateral side (Fig. |
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– | Mesotibia with pile otherwise, not markedly different between proximal and distal part (Figs |
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16 | All mesotarsomeres, except the most distal, with conspicuous equally long yellow pile along the posterior edge (Fig. |
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– | Mesotarsomeres with either pale yellow pile absent or with pale yellow pile inconspicuous (Fig. |
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17 | Face conical in profile, extending forward ventrally (Fig. |
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– | Face not conical (e.g. Figs |
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18 | Metafemur and metatibia strongly curved (Fig. |
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– | Metafemur and metatibia not markedly curved (posterior view) (Fig. |
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19 | Metafemur with two areas of dense, conspicuous black pile in the posteroventral section (Fig. |
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– | Metafemur with pile distribution otherwise |
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20 | Profemur with conspicuous thick black pile amongst the yellow pile on ventral proximal 1/4; metafemur with conspicuous black pile amongst the yellow pile on ventral proximal 1/5; metatibia with a tuft of longer, black pile on posteroventral proximal end (Fig. |
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– | Profemur with, at most, some thin black pile amongst the yellow pile on ventral proximal 1/4 (Fig. |
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21 | Profemur without long, black pile on basoventral section (Fig. |
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– | Profemur with a few long, black pile on basoventral section (Fig. |
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Note: the females of
1 | Thorax and abdomen reddish-brown (Fig. |
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– | Thorax and abdomen dark brown to black; second abdominal tergite either with one pair of yellow-orange maculae (e.g. Fig. |
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2 | Face with ground colour black (but often strong white pilose and pollinose) (Figs |
3 |
– | Face with ground colour white to yellow (e.g. Figs |
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3 | Abdomen entirely black (Fig. |
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– | Abdominal tergite II with pair of large orange maculae (Figs |
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(Note: we suspect that the female of |
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4 | Abdomen (almost) black, but with tergites II and III with a pair of vague, lateral maculae (Figs |
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– | Abdomen yellow or orange and black, with a pair of lateral maculae or vittae on tergites II and III well visible (e.g. Figs |
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5 | Abdomen nearly black (Fig. |
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– | Abdomen very dark but with a pair of vague maculae on tergites II and III (Figs |
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6 | Frons black pilose on its entire length, except laterally (Figs |
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– | Frons pale pilose on ventral half (Figs |
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(Note: we suspect that the female of |
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7 | All legs black, except for protarsus which is reddish-brown (Fig. |
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– | Legs, inclusive protarsus, very dark (Fig. |
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8 | Tergite II with pair of small yellow-orange maculae, laterally only reaching to halfway tergal length, medially very narrow, pointed; tergite III, pair of anterolateral yellow-orange maculae diffuse (Fig. |
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– | Tergite II with pair of large yellow-orange maculae, laterally almost reaching tergal posterior end, medially rounded; tergite III, pair of anterolateral yellow-orange maculae clear (Fig. |
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9 | Protibia with very conspicuous black pile over its entire length; pile on posterior side of mesotibia black on distal half, yellow on proximal half; metafemur without a ventral swelling in the middle (Fig. |
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– | Protibia either with inconspicuous black pile or black pile restricted to distal half; pile on posterior side of mesotibia black at most in 1/4 of distal end, otherwise yellow; metafemur with a small ventral swelling in the middle (Fig. |
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10 | Pro- and mesotibia without black pile ventrally (Fig. |
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– | Pro- and mesotibia with black pile ventrally (Fig. |
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11 | Tergite II with yellow fascia (Figs |
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– | Tergite II with a pair of yellow maculae (Figs |
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12 | Mesotibia with black pile either absent or very inconspicuous, but with a few thick, black spines at distal ventral end |
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– | Mesotibia with black pile on mesotibia conspicuous in ventral distal half, without thick, black spines at distal end |
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13 | Pro- and metafemur, as well as pro- and metatibia yellow-brown with distal half somewhat darkened, dorsally for a large part covered with strongly contrasting setae-like black pile (Fig. |
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– | Pro- and metafemur dark brown to black with distal end yellow-orange to orange-brown; pro- and metatibia yellow-orange to orange-brown in proximal half, dark brown to black in distal half (Fig. |
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14 | Metafemur with clear ventral swelling on middle (Fig. |
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– | Metafemur without ventral swelling on middle (Fig. |
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15 | Face markedly produced downward (Figs |
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– | Face not markedly produced downwards (Figs |
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16 | Mesofemur with very few, short black pile on distal end ventrally |
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– | Mesofemur with long black pile ventrally, especially on distal half |
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The male of
Unknown.
Uganda.
This is a new species to the Afrotropical Region and only collected from Uganda. The female remains unknown, despite the fact that 28 males were collected or encountered in various collections.
The specific epithet
(Morphotype with conspicuous spine on metatibia; see Variation, comments and discussion). “ARABIA” • 1♂; Abu; date unknown; C.G. Nurse leg.;
(Morphotype with low spine on metatibia; see Variation, comments and discussion). Ghana • 9♂♂; Tamale; Nov 1916; J.J. Simpson leg.;
Males of this species are highly variable in their morphology. Some males (spined morph) have a tooth-like projection (spine) on the distal ventral end of the metatibia and the pile on the posterventral distal end of the metafemur is predominantly black. The nominal morph does not have a tooth-like projection (spine) on the distal ventral end of the metatibia and the pile on the posterventral distal end of the metafemur is predominantly yellow. We found 11 males from Zambia, Nigeria and Ghana with a very low spine on the distal ventral end of the metatibia; some of these had a broad, yellow fascia on tergite II, while others had a pair of large, yellow maculae on tergite II.
The females also show substantial variation in their morphology. Females of the spined morph have a broad yellow-orange fascia on tergite II, whereas females of the nominal morph have one pair of large, yellow-orange maculae. Females are variable in the colour of the legs (varying from brown to black) and the abdominal pattern, with some females almost entirely lacking black abdominal markings. Especially the extent of the black markings is variable. In some specimens from Benin, the black markings were very vague so that specimens had an almost yellow-orange abdomen.
‘Arabia’, Benin, Burundi, Cameroon, Democratic Republic of the Congo, Ethiopia, Ghana, Kenya, Liberia, Madagascar, Malawi, Mali, Mozambique, Nigeria, Senegal, South Africa, Tanzania, Togo, Uganda, Zambia and Zimbabwe.
The male syntype of
Apart from the differences outlined above, males and females of both morphs are similar in morphology and male genitalia of both morphotypes are similar as well (compare Fig.
The species is widespread in the Afrotropical Region and has also been reported from “Arabia” (a male from Abu collected by C.G. Nurse; see examined material above). Arabia is the peninsular region, together with offshore islands, located in the extreme south-western corner of Asia. It is bounded by the Red Sea on the west and southwest, the Gulf of Aden on the south, the Arabian Sea on the south and southeast and the Gulf of Oman and the Persian Gulf on the east. It includes the modern coastal Arabian states of Yemen, Oman and the United Arab Emirates which, in a zoogeographical context, are part of the Afrotropical Region. However, we could not trace any reference of the collector of the specimen (C.G. Nurse) for the Afrotropical Region. Rather, C.G. Nurse has collected insects on Mount Abu, which is in Rajasthan (India) (see
Angola • 1♂ 1♀; 30 km NE of Duque de Braganza; Nov–Dec. 1957; G.H. Heinrich leg.;
Angola, Botswana, Democratic Republic of the Congo, Eswatini, Ethiopia, Ghana, Kenya, Madagascar, Malawi, Mozambique, Rwanda, South Africa, Togo, Uganda, Zambia and Zimbabwe.
The study of the type material shows that
Benin • 2♂♂; Ahozon; date unknown; G. Goergen leg.;
Benin, Democratic Republic of the Congo and Nigeria.
The female of the species was hitherto unknown. The male cannot be confused with any other species.
Males of
Paratype: Kenya • 1♂; Sosoma area; 30 Jun–6 Jul 2018; R. Copeland leg.;
unknown.
Kenya.
This is a new species to the Afrotropical Region. The species is only known from two males from Kenya. Two DNA barcodes are available (Fig.
Named in honour of Robert Copeland (
Benin • 1♂ 1♀; Ifangni-range; 6 Jun 2015; G. Goergen leg.;
Benin, Cameroon, Democratic Republic of the Congo, Ghana, Nigeria, Sierra Leone, South Africa, Togo and Uganda.
Malawi • 1♂; Mount Mulanje; 20 Oct 1912; S.A. Neave leg.;
Unknown.
Malawi, Senegal and South Africa.
Unknown.
Uganda.
The specific epithet
The female of
Unknown.
Madagascar.
Madagascar • 1♀; Antananarivo, Tsimbazaza; 16 Oct 1993; M. Hauser leg.;
(Fig.
Madagascar.
The type series comprises more than 50 specimens of both sexes collected from a dozen of sites from the central and eastern domains of Madagascar (
Benin • 5♀♀; Azaourissé; 7 Mar 2018; K. Jordaens leg.;
Benin, Cameroon, Chad, Democratic Republic of the Congo, Malawi and Mozambique.
Two female syntypes at the
Democratic Republic of the Congo • 1♀; Eala; 24 Aug 1935; J. Ghesquière leg.;
Democratic Republic of the Congo, Malawi, Tanzania and Uganda.
Previously only known from the holo- and paratype.
Ghana • 1♂; Eastern Region, N of Kibi, Atewa Range Forest Reserve; 21 Jun 2006; K.-D.B. Dijkstra leg.;
Unknown.
Democratic Republic of the Congo, Ghana and Togo.
The species is very similar in morphology to
Benin • 1♂; Calavi; 11 Nov 1993; G. Goergen leg.;
Unknown.
Benin, Democratic Republic of the Congo, Kenya, Tanzania and Uganda.
We could not find the male holotype in any of the surveyed collections. The male has a set of unambiguous character states mentioned in the original description and cannot be confused with any other species of the genus. The specimens we have studied correspond with the original species description and are therefore considered to be conspecific.
Benin • 2♂♂ 1♀; Calavi; Apr 2014; G. Goergen leg.;
Benin, Cameroon, Democratic Republic of the Congo, Nigeria and Togo.
The male has a set of unambiguous character states mentioned in the original description and cannot be confused with any other species of the genus. The specimens we have studied correspond with the original species description and are, therefore, considered to be conspecific. Until now, the species was only known from the male holotype. We here report on the first females, which we matched with the males through DNA barcoding. The species seems locally common in west and central Africa.
Democratic Republic of the Congo • 1♀; Bolongo; 23 Jun 1936; J. Ghesquière leg.;
Democratic Republic of the Congo, Malawi, Togo and Uganda.
The male has a set of unambiguous character states mentioned in the original description and cannot be confused with any other species of the genus. The specimens we have studied correspond with the photographs of the type and are, therefore, considered to be conspecific. Until now, the species was only known from the male holotype. We here report on the first females, which we matched with the males through DNA barcoding. The species seems rare throughout a large part of the Afrotropical Region and seems absent from southern Africa.
Benin • 1♂; Cotonou; Feb 2003; G. Goergen leg.;
Benin, Chad, Kenya, Oman and Yemen.
Madagascar • 2♀♀; Alaotra, Station Agric.; 24 Dec 1957; B.R. Stuckenberg leg.;
Madagascar.
Morphologically, the species is similar to
Benin • 1♂ 1♀; Azaourissé; 7 Mar 2018; K. Jordaens leg.;
Benin, Burundi, Cameroon, Democratic Republic of the Congo, Gabon, Ghana, Guinea-Bissau, Kenya, Madagascar, Malawi, Mozambique, Nigeria, Senegal, South Africa, Tanzania, Togo, Uganda and Zambia.
See
Democratic Republic of the Congo, Kenya, Malawi and South Africa.
This is a new species to the Afrotropical Region with a relatively wide distribution. The species morphologically resembles
The specific epithet
Democratic Republic of the Congo • 1♀; Banningville [= Bandundu], Kwilu River, Panga; Aug 1945; Fain leg.;
Democratic Republic of the Congo, Kenya, Malawi, Senegal, South Africa, Uganda, Zambia and Zimbabwe.
See
Unknown.
Togo.
This is a new species that is only known from three males from Kloto Forest, Togo.
The specific epithet
1♀ with locality and date unknown, D. Bruce leg. (
As male, except for the following character states: Eyes dichoptic (Fig.
Democratic Republic of the Congo, Kenya and Uganda.
This is a new species and the smallest in size of all Afrotropical
Named in honour of the Dipterist Dick Vockeroth (1928–2012), who already indicated on the labels that some specimens from Uganda probably belonged to a new species. The specific epithet should be treated as a noun in the genitive case.
In total, we recognise 23 valid
Neighbour-Joining tree (K2P distances) of 236 DNA barcodes of 18 Afrotropical
Continued. (Part 2).
Continued. (Part 3).
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Continued. (Part 6).
Interestingly, the species can be divided into a group of species with a strong sexual dimorphism and a group of species where the sexual dimorphism is very weak. Whereas the former group of species shows strong support in the
In general and especially for the species where males have an apical pile brush on the profemur, males are more commonly observed than females. A potential explanation could be that males of these species are often found in forests where they seem to defend small sunny patches and that females have a less conspicuous lifestyle. Species, in which the males do not have an apical pile brush on the profemur, occur in higher densities in more open habitat and are, therefore, more easily collected (Jordaens and Goergen pers. obs.). It would be worthwhile to compare the mating behaviour of the two male morphs. In some leaf cutter bees (genus
Phylogenetic tree of 18 Afrotropical
In species with a strong sexual dimorphism, male surstyli are simple (i.e. short, broadly rounded and covered with short, black spines) and male genitalia are morphologically very similar amongst species (Figs
In summary, Afrotropical
The DNA barcode analysis shows very low intraspecific variation in all species (Suppl. material
The
We would like to thank Y. Brodin (
Table S1. List of specimens, collection information, DNA voucher codes and GenBank/Barcode of Life Datasystems (BOLD) accession numbers used for the DNA barcode and phylogenetic analyses
species data
Table S2
molecular data
Intra- (diagonal and in bold) and interspecific (below diagonal) mean uncorrected