Research Article |
Corresponding author: Michel Sartori ( michel.sartori@vd.ch ) Academic editor: Ben Price
© 2020 Helen M. Barber-James, Sonia Zrelli, Zohar Yanai, Michel Sartori.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Barber-James HM, Zrelli S, Yanai Z, Sartori M (2020) A reassessment of the genus Oligoneuriopsis Crass, 1947 (Ephemeroptera, Oligoneuriidae, Oligoneuriellini). ZooKeys 985: 15-47. https://doi.org/10.3897/zookeys.985.56649
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The distinction between the two closely related genera Oligoneuriella Ulmer, 1924 and Oligoneuriopsis Crass, 1947 has been much debated. First described from South Africa, Oligoneuriopsis seemed to be a clearly defined genus. However, as the known distribution of the genus widened and knowledge on it expanded, species delimitation based on morphology became less clear due to overlap in several apparently defining morphological characters, especially in the nymphs. This work attempts to reassess Oligoneuriopsis morphology in the context of all currently known species. The type species, Oligoneuriopsis lawrencei Crass, 1947 is redescribed at the imaginal and nymphal stages and a neotype is designated. The putative nymph of Oligoneuriopsis dobbsi (Eaton, 1912) is described based on material collected around Mt Elgon (Kenya). The adults of Oligoneuriella orontensis Koch, 1980 are described for the first time and the species is transferred to the genus Oligoneuriopsis (Oligoneuriopsis orontensis comb. nov.). Egg structure is also described for the first time for the species Oligoneuriopsis skhounate and O. orontensis. Some biogeographical considerations are also given. It is likely that more species will still be discovered, especially in Africa.
Barcoding, generic concept, imaginal description, mayfly, neotype designation, new combination, nymphal description
Up to the middle of the 20th century, the only oligoneuriid genus widespread in the Afrotropical realm was Elassoneuria Eaton, 1881. In 1947, Crass described the genus Oligoneuriopsis to accommodate a new species, O. lawrencei, from the region then known as Natal (now KwaZulu-Natal), South Africa. Crass’ genus differs from Elassoneuria, the other genus occurring in sub-Saharan Africa, in wing venation differences in the adult stage, male genitalia features, and by the shape of the head in the nymphal stage (
Neither of these characters holds true for separating the nymphs of these two genera, as in the three South African Oligoneuriopsis species, the posterolateral abdominal spines on segments II to VII extend beyond the margin of the tergites, and the gill lamellae are shorter in several species.
The first record of O. skhounate in the Iberian Peninsula was published by
Due to the lack of clear distinctions between Oligoneuriella and Oligoneuriopsis nymphs, the generic concept relies mainly on male adult differences. Characters used to discriminate between the adults were proposed by
Another problem concerns the original description of Oligoneuriopsis lawrencei by
Another character to distinguish nymphs of Oligoneuriella and Oligoneuriopsis has been briefly mentioned by
Finally, a recent paper by
The aim of the present paper is to investigate and confirm the generic status in reviewing all species presently known. This will also allow us to reassess the generic position of the species Oligoneuriella orontensis Koch, 1980, based on the rich material collected from Israel (see
Material was examined from South Africa, Kenya, Israel, Algeria, Tunisia, Morocco, Iran and the Iberian Peninsula. Material includes nymphs (indicated as N), female subimagoes (s♀), male subimagoes (s♂), female imagoes (♀) and male imagoes (♂). All studied specimens belong to the following collections: Albany Museum, Grahamstown, South Africa (
It must be mentioned that all type specimens of Oligoneuriopsis from South Africa described by Crass and Agnew are certainly lost (
For genetic analysis we used the barcoding genetic marker cytochrome c oxidase subunit 1 (COI). We considered available sequences of three Oligoneuriopsis species (O. lawrencei, O. orontensis, and O. villosus), to which we added newly obtained sequences of fresh specimens of O. dobbsi and O. skhounate, thus representing the great majority of the described species in the genus. We used a non-destructive method for DNA extraction, i.e., specimens were incubated overnight soaked at proteinase K to allow DNA extraction without destroying the specimen. Amplification was done using the commonly used primers HCO2198 and LCO1490 (
Private identifiers of COI sequences used for the genetic analysis (GenBank accession numbers and BOLD process IDs).
Species | Database | Private identifiers |
---|---|---|
Oligoneuriopsis lawrencei | GenBank | MG516468 |
Oligoneuriopsis villosus | BOLD | EPHIR007-19, EPHIR008-19, EPHIR009-19, EPHIR010-19, EPHIR011-19 |
Oligoneuriopsis orontensis | GenBank | MN958842, MN958843, MN958844 |
Oligoneuriopsis dobbsi | GenBank | MT784191 |
Oligoneuriopsis skhounate | GenBank | MT784188, MT784189, MT784190 |
Oligoneuriella tuberculata | BOLD | EPHIR005-19 |
Oligoneuriella rhenana | GenBank | KY262260 |
Oligoneuriella pallida | GenBank | KU609047 |
Oligoneuriella tskhomelidzei | BOLD | EPHIR014-19 |
Oligoneuriella bicaudata | BOLD | BMIKU054-09 |
Oligoneuria amazonica | GenBank | KT201514 |
Homoeoneuria watu | GenBank | MG516463 |
Lachlania alcidesi | GenBank | KU609050 |
Madeconeuria sp. | GenBank | MG516465 |
We aligned and reconstructed the sequences in MEGA X v.10.0.5 (
Figure
Oligoneuriopsis lawrencei Crass, 1947: 53, figs 3, 4.
Neotype
: South Africa • 1N; Eastern Cape Province, Tributary of Tyume River, below Tor Doone, Hogsback; 32.5778°S, 26.9347°E; alt. 1445 m a.s.l.; 29 Feb. 1992; F.C. de Moor leg.;
Other material
: South Africa • 1N; Eastern Cape Province, Tsitsa River, at “The Falls”; 31.0214°S, 28.4819°E; alt. 1140 m a.s.l.; 26 Mar. 1991; F.C. de Moor & H.M. Barber leg.;
Lengths. Body: up to 14.8 mm; forewing: up to 14.9 mm; cerci: up to 17.0 mm; caudal filament: up to 12.8 mm.
Vertex light brown, frontoclypeus pale cream, broadly rounded apically, compound eyes black, base of ocelli black, ocelli whitish, antennae with scape and pedicel pale cream, first segment and flagellum light brown. Pronotum light brown, margins suffused with dark brown pigmentation. Pterothorax light brown, with pale cream-coloured unsclerotized line between meso and metanotal plate. Mesoscutellar filaments present. Forelegs shorter than mid or hind legs, with outer margin of femora, tibiae and tarsi dark brown, otherwise uniform pale brown colour; mid- and hindlegs cream to light brown, no distinct markings. All three pairs of legs appear to be functional. Tarsal claws paired, blunt. Wings (Fig.
Abdominal segments uniformly creamish, without distinct patterns, except tergites VII, IX, and X light brown; lateral margins with spine-shaped extensions from segment III to IX, of increasing length towards the posterior. Gonostyli whitish to grey, cerci whitish. Gonostyli 4-segmented, the basal one ca. 3 × the length of segments 2 to 4 combined. Penis lobes almost triangular, with characteristic sclerotized proximal process ending in a simple projection; apex of the lateral longitudinal lobe of penis in a small club-shaped sclerite (Fig.
Lengths. Body: up to 17 mm; forewing: up to 18.8 mm; cerci: up to 7 mm; caudal filament: up to 4.5 mm. Colouration as in the male; tibiae and tarsi of all legs appear to be functional. Cerci light to medium brown. Posterior margin of sternite IX deeply concave and rounded.
Lengths. Body up to 15 mm and 18.5 mm in male and female nymphs respectively; cerci (and caudal filament) up to 9.2 mm (4.0 mm) and 10.1 mm (3.5 mm) in male and female nymphs respectively. General colouration light to medium yellow-brown (Fig.
Specimens from KwaZulu-Natal are darker brown in colour than specimens with more southerly distribution, and first three abdominal segments darker brown in colour dorsally than remaining segments; faint paired median spots visible on the last five abdominal tergites in some KwaZulu-Natal nymphs. The head also possesses a dark brown marking present on the frons between the ocelli, and maxillary gills are much paler in colour relative to head capsule in KwaZulu-Natal specimens.
Winged stages were collected from the same locality as the nymphs in one instance, allowing association of the life stages. Imagos were seldom flying at the times of collection. Nymphs of O. lawrencei have a broadly rounded fronto-clypeal region, which easily distinguishes them from O. jessicae and O. elisabethae, both of which are more pointed in shape. Head very slightly carinate, less so than in O. elisabethae. Note that this is unlike the strong carination seen in Elassoneuria.
Found under large boulders (400–500 mm diameter) in swift current, often in rivers with bedrock substrate.
South Africa.
Oligoneuria dobbsi Eaton, 1912: 243, fig. 1 (female imago).
Oligoneuriella dobbsi: Ulmer, 1924: 32.
Oligoneuria sp.: Vayssière, 1936: 130 (nymph).
Oligoneuriopsis dobbsi:
Oligoneuriopsis grandaeva (Navás, 1936: 125, fig. 21) (female imago).
Kenya • 28N; Mount Elgon, Teremi upstream; 0.8973°N, 34.5973°E; alt. 2456 m a.s.l.; 13 Oct. 2019; W. Graf leg. • 23N; Mount Elgon, Teremi; 0.9094°N, 34.5994°E; alt. 2407 m a.s.l.; 13 Oct. 2019; W. Graf leg. • 13N; Mount Elgon, Kimurio upstream; 0.8913°N, 34.5892°E, alt. 2239 m a.s.l.; 11 Oct. 2019; W. Graf leg. • 46N (among them 1N – GBIFCH00890747 – sequenced); Mount Elgon, Kimurio tributary 2; 0.8956°N, 34.5878°E; alt. 2347 m a.s.l.; 8 Nov. 2019; W. Graf leg. • 15N; Mount Elgon, Kibisi upstream; 0.9028°N, 34.6175°E; alt. 2298 m a.s.l.; 9 Nov. 2019; W. Graf leg. • 8N; Mount Elgon, Kapkateny upstream; 0.8959°N, 34.5990°E; alt. 2293 m a.s.l.; 11 Oct. 2019; W. Graf leg. • 7N; Mount Elgon, Kapkateny midstream; 0.8325°N, 34.6234°E; alt. 1896 m a.s.l.; 12 Oct. 2019; W. Graf leg. • 2N; Mount Elgon, Kapkateny downstream;0.8144°N, 34.6243°E; alt. 1660 m a.s.l.; 14 Oct. 2019; W. Graf leg.; all MZL.
As redescribed by
Lengths. Body up to 17 mm and 25 mm in male and female nymphs respectively; cerci (and caudal filament) up to 10 mm and 11 mm in male and female nymphs, respectively.
General colouration medium to dark brown, in general darker in mature nymphs than in immature ones (Fig.
Cerci uniformly medium brown, caudal filament paler brown towards apex.
Oligoneuriopsis dobbsi male imago seems to be closely related to O. lawrencei from which it differs by the presence of crossveins in the proximal part of the subcostal area (see
The association of the nymphs from Mount Elgon with the adults described by
Kenya.
Oligoneuriopsis jessicae Agnew, 1973: 116, fig. 1A, B (nymph).
Eswatini (former Swaziland) • 14N; Malolotja stream, Nkomati River system; 26.1167°S, 31.1144°E; alt. 1227 m a.s.l.; 3 Mar. 2003; R. Bills leg.;
Unknown.
Lengths. Body up to 20 mm and 22 mm in male and female nymphs respectively; cerci (and caudal filament) up to 14 mm (4.5 mm) and 15.8 mm (6.9 mm) in male and female nymphs respectively. General colouration pale to hazelnut brown, with small, paired paler spots in the middle of each tergum of mature nymphs in some individuals; head pale to dark brown, without markings, darker between eyes, becoming paler brown towards distal margin of head (Fig.
Abdominal tergites darker than sternites, no distinctive markings except for dorsal paired paler brown spots on each side of the midline of the tergites in mature specimens; sharply pointed dorsal tubercles present on tergites I–VII, gradually decreasing in size posteriorly (Fig.
Whole nymph (dorsal aspect) and gills as illustrated by
Nymphs of O. jessicae mainly differ from those of O. lawrencei by the presence of sharply pointed dorsal tubercles on tergites I–VII. The dorsal setae along the hind femur are long in O. lawrencei, O. dobbsi and O. elisabethae, extending to the apex of the femur, while in O. jessicae the setae are shorter and taper off, not reaching the apex. Gills in O. jessicae are shorter than the half length of the corresponding tergite, as in O. elisabethae, while in O. lawrencei, the gills reach approximately half length of the corresponding tergite, even longer in O. dobbsi. Adult material is needed for comparison with other species.
Moss-covered stones in current. Nymphs mature in April (autumn).
Eswatini; South Africa: Mpumalanga near Barberton.
Oligoneuriopsis elisabethae Agnew, 1973: 118, fig. 1C (nymph).
Lesotho • 4N; Tsoelikana River; 29.9200°S, 29.0925°E; alt. 2247 m a.s.l.; 21 Jan. 1986; K. Meyer;
As with O. jessicae, the material examined by Agnew has been lost. This includes VAL 606G Klip River, Vrede-Volksrust Rd. Bridge 1959/01/14 27.35806°S, 29.35000°E, Free State Province, and VAL 1061B, VAL 1062A. Klein Vaal R., at Goedehoop Farm 1960/03/22 26.8194°S, 30.1333°E, Mpumalanga Province, F.M. Chutter leg. As the material examined is from a different catchment to the type material, no neotype has been designated.
Unknown.
Lengths. Body up to 16.5 mm (
Abdominal tergites uniformly pale brown, no distinctive patterns except for paired pale cream-coloured markings forming a V-shaped pattern on last three abdominal segments in some specimens (Fig.
Nymphs of O. elisabethae are less flattened compared to O. lawrencei, and have the shortest gills relative to the abdominal tergite length of the three South African species, at ca. 1/3 of the length of the tergites. Head similar in shape to O. jessicae but notably different to O. lawrencei, which is widest medially. Lateral abdominal spines are well developed; dorsal abdominal spines as seen in O. jessicae are absent in O. elisabethae. Nymphs of O. elisabethae also differ from those of O. skhounate, O. dobbsi, O. orontensis and O. villosus by the reduction of the caudal filament.
Found in cobble, pebble and gravel substrate in swift current.
Lesotho; South Africa: Free State and Mpumalanga Provinces.
Oligoneuriopsis skhounate Dakki & Giudicelli, 1980: 19, figs 14–29 (male imago, nymph).
Algeria • 1N (sequenced GBIFCH00763571); Oued Cherf, Medjez Amar; 36.44306°N, 7.31083°E; alt. 205 m a.s.l.; 3 Oct. 2018; B. Samraoui leg.; MZL • 2N (sequenced GBIFCH00763569–GBIFCH00763570); Oued Cherf, Dbabcha; 36.2166°N, 7.3181°E; alt. 610 m a.s.l.; 18 Oct. 2019; B. Samraoui leg.; MZL • Morocco • 3N; Marrakech, Palmeraie, Oued Tensift; 31.6619°N, 7.9694°W (estimated); alt. 443 m a.s.l.; 27 Apr. 1960; J. Aubert leg.; MZL • Spain • 4N; Pyrénées, Barbastro (Huesca), Rio Vero; 42.2400°N, 0.1278°W (estimated); alt. 1000 m a.s.l.; 24 Jun. 1956; H. Bertrand leg.; MZL • 1N; Sierra Morena, Venta de Cardenas; 38.4006°N, 3.5119°W (estimated); alt. 650 m a.s.l.; 2 Aug. 1960; J. Aubert leg.; MZL • 3N; Valladolid, Cabezon, Rio Pisuerga; 41.4650°N, 5.2297°W (estimated); alt. 650 m a.s.l.; 17 Aug. 1988; D. Studemann & P. Landolt leg.; MZL • 41N; Malaga, Cortes de la Frontera, Rio Guadairo; 36.5483°N, 5.3675°W (estimated); alt. 250 m a.s.l.; 21 Aug. 1988; D. Studemann & P. Landolt leg.; MZL • 4N, 10s♀, 17♂; same locality; 15 Sep. 1988; P. Landolt leg.; MZL • Tunisia • 1N; Bizerte, Mateur, Oued Joumine, upstream Lake Ichkeul dam; 36.9628°N, 9.5244°E; alt. 105 m a.s.l.; 20 Nov. 2004; S. Zrelli leg.; LBE • 22N, 1s♀; same locality; 26 Jun. 2005; S. Zrelli leg.; LBE • 20N, 2s♀; same locality; 18 Jul. 2005; S. Zrelli leg.; LBE • 40N; same locality; 28 Aug. 2005; S. Zrelli leg.; LBE • 40N; same locality; 6 Sep. 2005; S. Zrelli leg.; 39 LBE, 1 MZL • 40N; same locality; 24 Oct. 2005; S. Zrelli leg.; LBE • 35N; same locality; 26 Jun. 2006; S. Zrelli leg.; 24 LBE, 11 MZL • 11N; same locality; 31 Jul. 2006; S. Zrelli leg.; LBE • 2N, 1s♀; same locality; 6 Apr. 2009; S. Zrelli leg.; MZL • 2N; same locality; 17 May 2010; S. Zrelli leg.; LBE • 5N; Tabarka, Oued Bouterfes; 36.953°N, 8.9125°E; alt. 100 m a.s.l.; 4 Jan. 2005; S. Zrelli leg.; LBE • 6N; Jandouba, Fernana, Oued Ellil; 36.7203°N, 8.7339°E; alt. 237 m a.s.l.; 28 Jul. 2005; S. Zrelli leg.; LBE • 2N; same locality; 12 Sep. 2005; S. Zrelli leg.; LBE • 4N; same locality; 29 Jul. 2006; S. Zrelli leg.; LBE • 9N; same locality; 30 Aug. 2006; S. Zrelli leg.; LBE • 10N; same locality; 26 Jun. 2008; S. Zrelli leg.; LBE • 7N; Oued Ghezala; 36.6431°N, 8.6986°E; alt. 229 m a.s.l.; 30 Aug. 2006; S. Zrelli; LBE • 5N; same locality; 21 Nov. 2009; S. Zrelli; LBE.
Adequately described and illustrated by
(Fig.
General shape rhomboid, ca. 280 µm long and 250 µm wide, (Fig.
At the male adult stage, O. skhounate is distinguished from O. lawrencei by the presence of crossveins in the proximal part of the subcostal area, and from O. lawrencei and O. dobbsi by the shape of the apex of the lateral longitudinal lobe of penis sclerite which is only slightly enlarged. In the nymphal stage, O. skhounate differs from O. jessicae by the absence of abdominal carina and from O. lawrencei and O. elisabethae by the setation of the dorsal margin of hind femora with much longer setae; it also differs from O. dobbsi by the size of gill I lamella, much longer in the latter.
The ecology of the nymph in North Africa is described by
Algeria, Morocco, Spain, Tunisia.
Oligoneuriella orontensis
Israel • 1N; Jordan River, Ateret Fortress; 33.0032°N, 35.6286°E; alt. 63 m a.s.l.; 7 May 1990; H. Glassmann & M. Sartori leg.; MZL • 1N; same locality; 7 May 1991; H. Glassmann & M. Sartori leg.; MZL • 5N; same locality; 8 Dec. 2014; Z. Yanai leg.;
Lengths. Body: up to 18 mm; forewing: up to 17 mm; cerci: up to 15 mm; caudal filament: up to 13 mm.
Vertex light brown, frontoclypeus yellowish, compound eyes greyish black, base of ocelli black, ocelli whitish, antennae with pedicel light brown and flagellum medium brown.
Pronotum light brown, washed with grey. Pterothorax light brown, with a large mesonotal suture yellowish. Forelegs with outer margin of femora, tibiae and tarsi medium brown, inner margin yellowish; mid- and hindlegs yellowish, with distinct inner brown maculae on the femoro-tibial articulation; wings, when folded, light brown, almost whitish when unfolded.
Abdominal segments uniformly yellowish, without distinct patterns, except sides of tergite IX, tergite X and sternite IX light brown; gonostyli and cerci whitish.
Forelegs functional, tibiae and tarsi of middle and hind legs weakly sclerotized and non- functional. Tarsal claws blunt. Forewing typical of the genus, with 5 groups of veins: Sc+RA, RSa+iRS, RSp+MA1, MA2+MP1, and a forked MP2+CuA – CuP vein. Subcostal field with numerous transversal veins, those issued from RA not reaching iRS in the distal forth of the length, those between iRS and MA1 only present in the proximal half.
Gonostyli 4-segmented, the basal one ca. 4 × the length of segments 2 to 4 combined; a fifth segment can sometimes be present (Fig.
Lengths. Body: up to 23 mm; forewing: up to 21 mm; cerci: up to 7 mm; caudal filament: up to 5.5 mm.
Colouration as in the male, except antennal pedicel entirely medium brown, forefemora with outer margin sepia, tibiae and tarsi of all legs atrophied, twisted on forelegs; tarsal claws reduced to a single pointed and unsclerotized filament. Cerci light to medium brown. Posterior margin of sternite IX deeply concave and rounded.
(Fig.
Lengths. Body up to 14 mm and 19 mm in male and female nymphs respectively; cerci (and caudal filament) up to 7 mm (5 mm) and 9 mm (7 mm) in male and female nymphs respectively.
General colouration light to medium brown, always lighter in male nymphs. Head medium brown, yellowish between the compound eyes. Pronotum medium brown, with yellowish areas sublaterally. Pterothorax medium brown, with yellowish maculae very characteristic (see
General shape rhomboid, ca. 300 µm long and 270 µm wide, chorionic surface finely granulated (Fig.
In male imagos, O. orontensis differ from all other known species by the apex of the lateral sclerite of the penis, which is greatly enlarged, even more than in O. dobbsi, and the proximal process of the penis which is bifid. Nymphs are characterized by a row of setae on the outer margin of hind femora which does not reach the apex compared to other species studied, except O. jessicae to some extent, and differs to all other known species by the absence of a row of setae on hind tibiae.
In Israel, found in well-oxygenized streams with high water discharge and current velocity (
Israel, Lebanon, Syria, Turkey.
Oligoneuriopsis villosus
Bojková, Godunko & Staniczek, 2019 in
None.
Unknown.
As described by
The nymph of O. villosus can be easily differentiated from all other known species by the row of long and thin setae on the outer margin of hind femora reaching the apex, a row of long and thin setae on the outer margin of hind tibiae, posterolateral projections of abdominal segments diverging from body axis, the absence of posteromedian projections on abdominal terga, and posteromedian setae on sternites III–IV very long and dense.
Iran.
See comment under O. orontensis regarding reports from Iraq.
Iran • 2♂; Ghilan, Sefid-rud River, close to Rudbar [Roodbar]; app. 36.817°N, 49.433°E; alt. 180 m a.s.l.; 4 Aug. 1972; W. Heinz coll. & V. Puthz leg. to MZL.
Gonostyli 4-segmented, the basal one a little bit less than 4 × the length of segments 2 to 4 combined. Segment 2 not enlarged distally, more than 2 × longer than wide. Penis lobes with sclerotized proximal process ending in a single projection; lateral longitudinal lobe ending in a distinct club-shaped sclerite ca. 2 × larger than the lateral lobe (Fig.
These two specimens are in bad state (legs missing, wings broken), but nevertheless we think it is important to report this finding. The shape of the genitalia is different from those of the previous species, somewhat intermediary between those of O. skhounate and O. orontensis. Second segment of gonostyli is also much slender than in the two previous species. These specimens could be the alate stages of O. villosus, but they are reported from a far distant place (ca 700 km); hence they could also belong to a new, undescribed species. Due to these uncertainties and the lack of proper material, we prefer mentioning it without naming it.
Iran.
Adult. Male gonostyli four (sometimes five)-segmented, apex of the lateral longitudinal lobe of penis club-shaped, proximal process pointed, simple or bifid; three caudal filaments, five convex longitudinal veins in forewing.
Nymph. Head usually without a carina, though a slight carina can be seen in some species (not pronounced as in Elassoneuria). Hind femora with a row of dense setae reaching at least the middle of the dorsal margin. Abdominal gills shorter than or equal to length of associated abdominal segment; apically rounded and bordered by thin setae. Postero-medial patch of very long and thin setae, well developed on sternites II to IV, sometimes to sternite V or VI.
Generic affinities. As already mentioned by former authors, Oligoneuriopsis closely resembles Oligoneuriella from which it can be separated by the following characters:
In Oligoneuriopsis male imagos, the shape of the proximal process of the penes sclerite is apically pointed or bifid, but saddle-shaped in Oligoneuriella, the apex of the lateral longitudinal lobe of the penis is club-shaped, enlarged at apex, but not enlarged in Oligoneuriella, and gonostyli are composed of four(five) segments against three (four, rarely five) in Oligoneuriella (including the proximal, long segment). Contrary to what
In the nymphal stage, Oligoneuriopsis species possess a row of long and thin setae on the outer margin of the hind femora, whereas this row is absent or reduced to the proximal half of margin in Oligoneuriella (Fig.
1 | Abdominal tergites I–VII with median tubercles (Fig. |
O. jessicae |
– | Abdominal tergites without median tubercles | 2 |
2 | Outer margin of hind tibiae without a row of long and thin setae (Fig. |
O. orontensis |
– | Outer margin of hind tibiae with a row of long and thin setae (e.g., Fig. |
3 |
3 | Caudal filament much shorter than cerci (Fig. |
O. elisabethae |
– | Caudal filament subequal in length to cerci (e.g., Fig. |
4 |
4 | Frons slightly carinate (Fig. |
O. lawrencei |
– | Head without carina, lamella of gill I small but well visible; abdomen without contrasted markings (e.g., Fig. |
5 |
5 | Posterolateral projections of the abdomen clearly divergent from body axis ( |
O. villosus |
– | Posterolateral projections of the abdomen parallel to body axis (e.g., Fig. |
6 |
6 | Fibrillae of gill I as long as lamella; outer margin of hind tibiae with a row of rather short setae (Fig. |
O. dobbsi |
– | Fibrillae of gill I much longer than lamella; outer margin of hind tibiae with a row of long setae (Fig. |
O. skhounate |
Egg structure of O. skhounate and O. orontensis is similar to the one of O. villosus, as well as of Oligoneuriella species, but somewhat different to the one of Oligoneuriopsis sp. illustrated by
Based on these morphological characters, a new generic concept is proposed for Oligoneuriopsis, meeting the need for understanding the phylogenetic position and historical development of the genus. We trust that future study of the genus (e.g., description of new species, or of unknown life stages of known species) will confirm our findings.
The COI tree (Fig.
To date, seven species of Oligoneuriopsis are known. Four of them are described at nymphal and imaginal stages (O. dobbsi, O. lawrencei, O. skhounate, O. orontensis), and three only at the nymphal stage (O. jessicae, O. elisabethae, O. villosus). An additional, undescribed, species from Iran is mentioned here (Table
Species | Imago described | Nymph described | COI sequenced |
O. dobbsi | + | + | + |
O. elisabethae | + | ||
O. jessicae | + | ||
O. lawrencei | + | + | + |
O. orontensis | + | + | + |
O. skhounate | + | + | + |
O. villosus | + | + | |
O. sp. (Iran) | + |
We reconstructed the known distribution of the genus based on the material examined in this publication, and information from other sources (
With a cluster of species recorded in South Africa, the distribution suggests a once more widely spread group that has since been restricted to cooler climate at higher altitude as Gondwanaland moved north into warmer climatic zones, isolating populations of this originally cool-adapted lineage to produce the species we see today.
We thank the Department of Sport, Recreation Arts and Culture, Eastern Cape Government, South Africa, and Rhodes University, Makhanda, South Africa, for supporting research at the Albany Museum. ZY was funded by a Swiss Government Excellence Scholarship (FCS). We are indebted to Prof Wolfram Graf (BOKU, Vienna) for providing the material from Kenya, to Laban Njoroge (National Museums of Kenya) for supplementary distribution records from Kenya and to Prof Boudjéma Samraoui (Annaba University) for providing us with fresh material from Algeria. Marion Podolak (MZL) and Maud Liegeois (UNIL) are thanked for their dedication in the molecular lab work, and Jean-Luc Gattolliat (MZL) and Benjamin Kirkaldy (
The authors have declared that no competing interests exist.