Epeorus (Caucasiron) zagrosicus Hrivniak & Sroka, 2020

Hrivniak, Ľubos, Sroka, Pavel, Bojkova, Jindriska, Godunko, Roman J., Namin, Javid Imanpour, Bagheri, Samereh, Nejat, Farshad, Abdoli, Ashgar & Staniczek, Arnold H., 2020, Diversity and distribution of Epeorus (Caucasiron) (Ephemeroptera, Heptageniidae) in Iran, with descriptions of three new species, ZooKeys 947, pp. 71-102 : 71

Epeorus (Caucasiron) zagrosicus Hrivniak & Sroka sp. nov. Figures 5 , 6

Type material.

Holotype: female larva: IRAN, Lorestan Province, 4.5 km SW of Varayeneh village, Sarab-e Gamasiab River, 34°2'46.2"N, 048°22'32.6"E (locality no. 9); 1842 m a.s.l.; A. Staniczek, M. Pallmann, A. Abdoli, F. Nejat leg., 25.4.2017, SMNS_EPH_007520.

Paratypes: 79 female larvae, 68 male larvae: same data as holotype, SMNS_EPH_007520. 6 female (2 mounted on slide), 5 male (2 mounted on slide) larvae: IRAN, Chaharmahal and Bakhtiari Province, Dimeh village, Chehme-Dimeh River, 32°30'11.6"N, 050°13'04.5"E (locality no. 45); 2220 m a.s.l.; A. Staniczek, M. Pallmann, R. J. Godunko, F. Nejat leg., 5.5.2017, SMNS_EPH_007707. DNA extracted from 3 females (code: IR32, stored in EtOH; codes: IR34 and IR35, mounted on slides) and 2 males (codes: IR33b and IR36, mounted on slides).

15 female (3 mounted on slide), 5 male larvae: IRAN, Kohgiluyeh and Boyer-Ahmad Province, 4 km E of Yasuj, Yasuj fall, 30°40'34.7"N, 051°37'35.6"E (locality no. 37); 2060 m a.s.l.; A. Staniczek, M. Pallmann, R. J. Godunko, F. Nejat leg., 4.5.2017, SMNS_EPH_007568. DNA extracted from 2 females (code: SP38, mounted on slide; code: IR33a, stored in EtOH) and 1 male (code: SP37, stored in EtOH).

2 female, 2 male larvae: IRAN, Chaharmahal and Bakhtiari Province, 5 km W of Chelgerd, Kouhrang River, 32°28'9.3"N, 050°5'26.2"E (locality no. 46); 2402 m a.s.l.; A. Staniczek, M. Pallmann, R. J. Godunko, F. Nejat leg., 5.5.2017, SMNS_EPH_007689.

The holotype and 100 paratypes are deposited in SMNS, 50 paratypes (including DNA extracted specimens) are deposited in IECA and 32 paratypes in MMTT_DOE.

Other material examined:

42 larvae: same data as holotype; young instars or damaged specimens.

1 male larva: IRAN, Chaharmahal and Bakhtiari Province, 4 km E. of Bajgiran, Dehno River, 31°54'26.2"N, 050°42'20.6"E (locality no. 50); 1721 m a.s.l.; A. Staniczek, M. Pallmann, R. J. Godunko, F. Nejat leg., 6.5.2017, SMNS_EPH_007606.

Etymology.

The species name refers to its known records in the Zagros mountain range.

Localities and habitat preferences of larvae.

Larvae were found in five streams of different size at high altitude, above 1700 m a.s.l. Three streams were strongly turbulent rivers with very coarse bed substrate flowing in high-mountain valleys (Fig. 10E ). Larvae were found also in a shallow, slow-flowing brook with finer, gravel substrate flowing in the forest (locality near Yasuj fall, Fig. 10F ), and in a small stream with moderate, slightly turbulent flow and stony bed substrate with fine gravel, silt, and macrophytes (Chehme-Dimeh River). The species was not found in streams that were polluted or seasonally drying out.

Description of larva.

General colouration of larvae yellowish brown with dark brown maculation. Body length of mature larvae 13.5-14.5 mm (female), 10.0-11.0 mm (male). Length of cerci approximately 1.3 × body length.

Head. Shape trapezoidal; anterior and lateral margin rounded, posterior margin slightly rounded or nearly straight (Fig. 5D, E ). Anterior margin with shallow concavity medially.

Head dimensions of mature larvae: length 2.6-2.7 mm, width 3.6-4.0 mm (female); length 2.3-2.4 mm, width 3.3 mm (male). Head width/length ratio: 1.36-1.49 (both male and female).

Dorso-medial part with indistinct brown rectangular or oval macula, sometimes reduced to pair of stripes. Rounded maculae under lateral ocelli and blurred or triangular maculae near inner edges of compound eyes. Pair of pale stripes extending from lateral ocelli to lateral edges of head. Pair of maculae located along coronal suture. Compound eyes dark grey to black in female, brownish and basally blackish in male mature larva. Ocelli dark grey to black, basally paler. Antennae yellowish-brown, scapus and pedicellus darkened. Anterior margin densely covered with hair-like setae extending to lateral margins and directed medio-dorsally. Dorsal surface covered with fine hair-like setae and sparsely distributed stick-like setae. Sparse longer, fine, hair-like setae located posteriorly to eyes.

Mouthparts. Labrum (Fig. 6A ) widened anteriorly, with anterior margin slightly rounded or nearly straight (in dorsal view). Lateral angles rounded (shape of labrum may vary among individual specimens). Dorsal surface (Fig. 6A , right half) sparsely covered with setae of different size; four longer, bristle-like setae located antero-medially and two antero-laterally. Epipharynx with longer, shortly plumose bristles situated along lateral to anterior margin (Fig. 6A , left half; range of setation figured as large black dots), and brush of fine hair-like setae medially (not figured). Posterior margin of labrum irregularly concave; with group of 6-10 setae of various size located on ventral surface close to posterior margin. Outer incisors of both mandibles (Fig. 6B, C ) with three apical teeth; outer tooth blunt in both mandibles. Inner incisor of left mandible with three apical teeth, right inner incisor bifurcated.

Thorax. Pronotum anteriorly narrowed, lateral edges nearly straight. Metanotum with slight postero-medial projection. Dorsal surface covered with fine hair-like setae (as on abdominal terga and head); sparse longer hair-like setae along pro, meso- and metanotal suture.

Legs. Colour pattern of femora as in Fig. 5F . Femora with rounded medial hypodermal femur spot. Patella-tibial suture darkened; tarsi proximally and distally darkened. Coxal projections of fore- and hind legs pointed or bluntly pointed; of middle legs blunt. Trochanteres with spatulate setae as on dorsal surface of femora (Fig. 6D ). Tibiae of forelegs 1.20-1.31 × femur length, tibiae of middle legs 1.06-1.14 × femur length, and tibiae of hind legs 0.90-1.04 × femur length. Tarsi of all legs 0.25-0.34 × tibia length. Dorsal surface of femora covered by elongated and sporadically short rounded spatulate setae (Fig. 6D ); hair-like setae and sparsely distributed stick-like setae. Anterior margin of femora with short, pointed and/or bluntly pointed spine-like setae; posterior margin with row of long blade-like setae and sparse row of bluntly pointed spine-like setae. Dorsal margin of tibiae and tarsi with row of long setae; ventral margin of both with irregular row of spine-like setae accumulated distally. Tarsal claws with two or three denticles.

Abdominal terga. Colour pattern of abdominal terga includes transversal stripe along anterior margin of terga I-IX (X) medially extending to triangular, short rectangular or stripe-like medial macula on terga (III) IV-IX (transversal stripe sometimes not distinctly extended, for variability see Fig. 5A, H-J ). Pair of sigilla sometimes coloured, in form of short stripes or spots located antero-laterally to medial macula. Tergum X without distinct maculation. Lateral margins of abdomen with oblique maculae on terga I-IX extending to dorso-posterior margin. Denticles along posterior margin on terga of various size, irregular and pointed, sometimes curved (Fig. 6E ). Surface of terga covered with hair-like setae and sparsely with stick-like setae. Supra-tergalial projections short and blunt. Tergum X with more or less developed postero-lateral projections (Fig. 6H, I , arrows). Longitudinal row of hair-like setae medially along abdominal terga present.

Abdominal sterna. Yellowish, with distinct colouration pattern consisting of anteriorly widened pair of stripes (medio-anterior sigilla) on terga II-VIII (Fig. 5B, G, K ). Sometimes only oblique stripes are present, without anterior widening (especially on sterna VI-VIII). Nerve ganglia occasionally darkened. Intensity of colouration varies among individuals. Sternum IX with V-shaped medial emargination; surface covered by irregularly distributed short hair-like setae, and medially accumulated longer hair-like setae (Fig. 6J, K ).

Gills. Dorsal surface of gill plate I yellowish; of gill plates II-VII greyish on anterior half and brownish to reddish on posterior half. Ventral margin of all gill plates yellowish. Projection of gill plate III well developed (Fig. 6G ). Shape of gill plate VII (in natural position from ventral view) varies from narrow to relatively wide (Figs 5G , 6M-O ). Gill filaments reaching to 0.4-0.5 × length of respective plate, filaments of gill VII to 0.24-0.30 × (in late-instar larvae).

Cerci. Brownish, basally darkened.

Subimago, imago and eggs.

Unknown

Morphological diagnostics of larvae.

The main larval diagnostic characters of E. (C.) zagrosicus sp. nov. are as follows: (i) colour pattern of abdominal sterna (Fig. 5B, G, K ) and abdominal terga (Fig. 5A, H-J ), (ii) presence of postero-lateral projections on tergum X (Fig. 6H, I ), (iii) presence of hypodermal medial femur spot (Fig. 5F ), and (iv) fine hair-like setae on surface of abdominal terga (Fig. 6E ).

Affinities.

Based on the colour pattern of abdominal sterna, E. (C.) zagrosicus sp. nov. is most similar to E. ( C. ) caucasicus and E. ( C. ) iranicus . Both latter species possess pigmented medio-anterior sigilla forming a pair of oblique stripes on abdominal sterna II-VIII (e.g., Braasch 1979: 284, fig. 3b), and a medial hypodermal femur spot. However, E. (C.) zagrosicus sp. nov. differs by the distinct widening at the anterior margin of medio-anterior sigilla of abdominal sterna. If the sternal colour pattern is not fully developed (sporadically only stripes are present on all or several sterna), E. (C.) zagrosicus sp. nov. is distinguishable by the colour pattern of abdominal terga (Fig. 5A, H-J ), which is different in E. ( C. ) caucasicus ( Braasch 1979: 284, fig. 3a) and E. ( C. ) iranicus ( Braasch and Soldán 1979: 264, fig. 12). In E. (C.) zagrosicus sp. nov., the postero-lateral projections on the tergum X are well-developed, whereas they are not significantly pronounced in either of the two species mentioned above (only small projections may be sporadically present).

Distinct postero-lateral projections on the tergum X are characteristic for E. ( C. ) magnus , E. (C.) nigripilosus , and E. (C.) alborzicus sp. nov. Small projections are also sporadically present in E. ( C. ) znojkoi . E. ( C. ) magnus can be easily distinguished from E. (C.) zagrosicus sp. nov. by the absence of colour pattern of abdominal sterna, the absence of a medial hypodermal femur spot, and setation on dorsal margin of labrum (numerous thickened bristle-like setae, Hrivniak et al., in prep.). E. (C.) nigripilosus and E. (C.) alborzicus sp. nov. differ by a typical colouration pattern of abdominal sterna ( Sinitshenkova 1976: 89, fig. 28 for E. (C.) nigripilosus and Fig. 1B, G, K-M for E. (C.) alborzicus sp. nov.). E. ( C. ) znojkoi can be distinguished from E. (C.) zagrosicus sp. nov. by the colour pattern of abdominal terga and characteristic reddish colouration of abdominal sterna ( Braasch 1980: 172, fig. 4b, c).

The presence of a medial hypodermal femur spot makes E. (C.) zagrosicus sp. nov. slightly similar to E. ( C. ) turcicus and E. (C.) alborzicus sp. nov. However, the presence of the characteristic pattern of abdominal sterna in E. (C.) alborzicus sp. nov. (Fig. 1B, G, K-M ), and the absence of colouration pattern of abdominal sterna in E. ( C. ) turcicus reliably differentiate both species from E. (C.) zagrosicus sp. nov. Additionally, E. ( C. ) turcicus differs by the characteristic colour pattern of abdominal terga ( Hrivniak et al. 2019: 61, fig. 1).

The other five species distributed in the Caucasus, namely E. ( C. ) sinitshenkovae , E. ( C. ) alpestris , E. ( C. ) bicolliculatus , E. ( C. ) longimaculatus , and E. ( C. ) soldani , do not share any important diagnostic characters with E. (C.) zagrosicus sp. nov. Nevertheless, E. ( C. ) sinitshenkovae and E. ( C. ) alpestris can be separated from E. (C.) zagrosicus sp. nov. by the absence of a medial hypodermal femur spot, overall colouration of the dorsal surface of femora ( E. ( C. ) sinitshenkovae , Braasch and Zimmerman 1979: 106, fig. 10), and the different colouration of abdominal sterna ( E. ( C. ) alpestris , Braasch 1979: 284, fig. 1d). Fine hair-like setae on the dorsal surface of abdominal terga clearly distinguish E. (C.) zagrosicus sp. nov. from E. ( C. ) bicolliculatus , E. ( C. ) longimaculatus , and E. ( C. ) soldani . All three species are characteristic by the presence of flattened setae on abdominal terga ( Hrivniak et al. 2017: 359, figs 23-25).

Figures

Figure 1. Epeorus (Caucasiron) alborzicus sp. nov., larva: A habitus in dorsal view B habitus in ventral view C habitus in lateral view D head of male in dorsal view E head of female in dorsal view F middle leg in dorsal view G distal part of abdomen in ventral view H-J colouration of abdominal terga K-M colouration of abdominal sterna.

Figure 5. Epeorus (Caucasiron) zagrosicus sp. nov., larva: A habitus in dorsal view B habitus in ventral view C habitus in lateral view D head of male in dorsal view E head of female in dorsal view F middle leg in dorsal view G distal part of abdomen in ventral view H-J colouration of abdominal terga K colouration of abdominal sterna.

Figure 6. Epeorus (Caucasiron) zagrosicus sp. nov., larva: A labrum (right half in dorsal view, left half in ventral view) B incisors of right mandible in ventral view C incisors of left mandible in ventral view (both flattened on slide) D setae on dorsal surface of femora E surface and posterior margin of abdominal tergum VII F gill I G gill III H-I abdominal segments VIII-X J sternum IX, female K sternum IX, male L gill VII (flattened on slide) M-O gill VII (in natural position from ventral view), variability in shape.

Figure 10. Photos of the localities of the new Epeorus (Caucasiron) species described herein: A unnamed brook near Panjab village - type locality of E. (C.) alborzicus sp. nov. B unnamed brook near Kahrud-e Bala village - locality of E. (C.) alborzicus sp. nov. C unnamed river near Shirinabad village - type locality of E. (C.) shargi sp. nov. D unnamed brook near Chah-e Ja village - locality of E. (C.) shargi sp. nov. E Gamasiab River near Varayeneh village - type locality of E. (C.) zagrosicus sp. nov. F Yasuj fall near Yasuj village - locality of E. (C.) zagrosicus sp. nov.