Epeorus (Caucasiron) shargi 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) shargi Hrivniak & Sroka sp. nov. Figures 3 , 4

Type material.

Holotype: female mature larva: IRAN, Golestan Province, Shirinabad village, unnamed river; 36°48'01.4"N, 055°01'05.8"E (locality no. 108); 740 m a.s.l.; J. Bojková, T. Soldán, J. Imanpour Namin leg., 27.4.2018, SMNS_EPH_010057.

Paratypes:

19 female, 11 male larvae: same data as holotype.

36 female (5 mounted on slide), 25 male (1 mounted on slide) larvae: IRAN, Golestan Province, above Chah-e Ja village, unnamed brook (RT of river flowing to Fazelabad); 36°40'22.8"N, 054°46'37.9"E (locality no. 104); 1450 m a.s.l.; J. Bojková, T. Soldán, J. Imanpour Namin leg., 27.4.2018. DNA extracted from 2 females (codes: IR23 and IR24, mounted on slides).

19 female (3 mounted on slide), 7 male (1 mounted on slide) larvae: IRAN, Golestan Province, below Chah-e Ja village (main valley), unnamed river flowing to Fazelabad, 36°41'46.3"N, 054°47'35.0"E (locality no. 105); 1240 m a.s.l.; J. Bojková, T. Soldán, J. Imanpour Namin leg., 27.4.2018. DNA extracted from 1 female (code: IR21, mounted on slide) and 1 male (code: IR22, stored in EtOH).

The holotype (SMNS_EPH_010057) and 50 paratypes (SMNS_EPH_010057) are deposited in SMNS, 50 paratypes (including DNA extracted specimens) are deposited in IECA, and 17 paratypes in MMTT_DOE.

Other material examined (not paratypes):

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

Etymology.

The species name derives from shargi (یقرش), which means eastern in Farsi. It refers to the distributional range of the species in the eastern part of the Alborz mountain range.

Localities and habitat preferences of larvae.

Larvae were found in three clear streams at middle altitude (740-1450 m a.s.l.) in the eastern Alborz (Fig. 9 ). Habitat conditions of these streams differed from each other. Larvae were abundant in a cold, alkaline brook (water conductivity 1320 μS /cm) with patches of precipitated calcium crusts on the bed and in the non-alkaline water (with water conductivity reaching the values of clear montane streams in the region, 433 μS /cm) of the type locality. Both localities were characterised by stony bed sediment with leaf litter debris and fine gravel along the banks, and by fast, turbulent flow (Fig. 10C, D ). Lower abundance of larvae was found in a river with uniform coarse substrate flowing in a wide gravel river channel. All streams were surrounded by deciduous forests (Fig. 10C, D ). The species was not found in urban and agricultural areas in this region where many localities were investigated.

Description of larva.

General colouration of larvae yellowish brown with dark brown maculation. Body length of mature larvae 13.7-15.6 mm (female), 11.7-13.0 mm (male). Length of cerci approximately 1.1 × body length.

Head. Shape trapezoidal; anterior and lateral margin rounded, posterior margin rounded in female, slightly rounded in male (Fig. 3D, E ). Anterior margin with shallow concavity medially. Head dimensions of mature larvae: length 3.0-3.2 mm, width 4.1-4.4 mm (female); length 2.70-2.95 mm, width 3.5-4.0 mm (male). Head width/length ratio: 1.33-1.40 (both male and female). Dorso-medial part with brown, rectangular or oval smudge, sometimes reduced to pair of stripes. Pair of maculae located between ocelli (sometimes fused into single macula). Rounded maculae lateroventral of lateral ocelli and blurred 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 of head densely covered with hair-like setae extending to lateral margins and directed medio-dorsally. Dorsal surface of head 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. 4A ) 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. 4A , right half) sparsely covered with setae of different size; 4-6 longer bristle-like setae located antero-medially and two antero-laterally. Epipharynx with longer, shortly plumose bristles situated along lateral to anterior margin (Fig. 4A , 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 5-10 setae of various size located on ventral surface close to posterior margin. Outer incisors of both mandibles (Fig. 4B, C ) with three apical teeth; outer tooth blunt in both mandibles. Inner incisor of left mandible with three apical teeth, right inner incisor bifurcated (inner side of right tooth usually with small denticle).

Thorax. Pronotum anteriorly narrowed, lateral edges nearly straight or slightly rounded. Metanotum with slight, blunt, 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. 3F . Femora with rounded or slightly elongated 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. 4D ). Tibiae of forelegs 1.23-1.28 × femur length, tibiae of middle legs 1.03-1.50 × femur length, and tibiae of hind legs 0.87-1.06 × femur length. Tarsi of all legs 0.28-0.32 × tibia length. Dorsal surface of femora covered by short, sporadically elongated spatulate setae (Fig. 4D ), 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 2-3 denticles.

Abdominal terga. Colour pattern of abdominal terga (Fig. 3A, H-K ) consists of transversal stripe along anterior margin of terga I-IX (X) medially extending to i) triangular or blurred macula on terga (II) III-IV; ii) triangular or T-shaped macula on terga V-IX, reaching to half or stretching to posterior margin of corresponding tergum (medial macula of terga VIII and IX often widened). Transversal stripe along anterior margin of terga laterally extends to pair of short maculae. Medial maculae often surrounded by pale background. Tergum X without distinct maculation. Pair of sigilla sometimes coloured and forming pair of short stripes adjacent laterally to medial macula. Lateral margins of abdomen with oblique maculae on terga I-IX. Denticles along posterior margin on terga of various size, irregular and pointed (Fig. 4E ). Surface of terga covered with hair-like setae and sparsely with stick-like setae. Supra-tergalial projections short and blunt. Tergum X without distinct postero-lateral projections (Fig. 4H ). Longitudinal row of hair-like setae along abdominal terga present medially.

Abdominal sterna. Yellowish, without distinct colour pattern. Nerve ganglia often dark brown pigmented (Fig. 3B, G, L ). Sternum IX with V-shaped medial emargination; surface covered by irregularly distributed short hair-like setae and medially accumulated longer hair-like setae (Fig. 4I, J ).

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. 4G ). Gill plate VII relatively wide (in natural position of ventral view, Figs 3G , 4L ). Gill filaments reaching to 0.41-0.50 × length of respective plate, filaments of gill VII to 0.24-0.28 × (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.) shargi sp. nov. are as follows: (i) colour pattern of abdominal terga (Fig. 3A, H-K ) and no colouration of abdominal sterna (Fig. 3B, G, L ), (ii) lack of distinct postero-lateral projections on tergum X (Fig. 4H ), (iii) presence of medial hypodermal femur spot (Fig. 3F ), (iv) relatively wide shape of gill plate VII (in natural position from ventral view; Figs 3G , 4L ), and (v) fine hair-like setae on surface of abdominal terga (Fig. 4E ).

Affinities.

Based on the colour pattern of abdominal terga and sterna, E. (C.) shargi sp. nov. resembles several species distributed in the Caucasus and adjacent areas. At first glance, E. ( C. ) soldani and E. ( C. ) turcicus are most similar. Larvae of E. ( C. ) soldani possess triangular maculae on abdominal terga ( Braasch 1979: 284, fig. 2b) and an indistinct, sometimes not expressed, colour pattern of abdominal sterna. It can be distinguished from E. (C.) shargi sp. nov. by a comparatively narrower gill plate VII (in natural position from ventral view), the presence of flattened setae on the surface of abdominal terga ( Hrivniak et al. 2017: 359, fig. 25), and the absence of a medial hypodermal femur spot.

Epeorus (C.) turcicus shares with E. (C.) shargi sp. nov. the lack of colouration on abdominal sterna ( Hrivniak et al. 2019: 61, fig. 2), the presence of a medial hypodermal femur spot ( Hrivniak et al. 2019: 62, fig. 9), and fine hair-like setae on the dorsal surface of abdominal terga ( Hrivniak et al. 2019: 63, fig. 11). Nevertheless, E. ( C. ) turcicus differs from E. (C.) shargi sp. nov. by the different colour pattern of abdominal terga, with anteriorly widened stripe stretching between anterior and posterior margins ( Hrivniak et al. 2019: 61, fig. 1), in contrast to E. (C.) shargi sp. nov. with more or less triangular maculae on abdominal terga (Fig. 3A, H-K ), and a distinctly narrower gill plate VII (in natural position from ventral view) ( Hrivniak et al. 2019: 63, figs 15, 16).

Similar to E. (C.) shargi sp. nov., there is no colour pattern of abdominal sterna in several other species, namely E. ( C. ) longimaculatus , E. ( C. ) sinitshenkovae , and E. ( C. ) magnus . Epeorus (C.) longimaculatus can be clearly separated from E. (C.) shargi sp. nov. by (i) a distinctly narrower gill plate VII (in natural position of ventral view), (ii) flattened setae on the surface of abdominal terga ( Hrivniak et al. 2017: 359, fig. 25), (iii) poorly developed projection on the costal margin of gill plate III ( Braasch 1980: 172, fig. 6b), and (iv) elongated medial hypodermal femur spot ( Braasch 1980: 172, fig. 11).

Epeorus (C.) sinitshenkovae can be distinguished from E. (C.) shargi sp. nov. by the absence of a medial hypodermal femur spot, the characteristic colour pattern of femora (Braasch and Zimmerman 1979: 106, fig. 10), and the colour pattern of abdominal terga ( Braasch 1979: 105, fig. 2).

Epeorus (C.) magnus can be reliably distinguished by the presence of distinct postero-lateral projections on abdominal tergum X and characteristic setation of labrum (numerous thickened bristle-like setae, Hrivniak et al. in prep.).

All other species distributed in the Caucasus and adjacent areas differ from E. (C.) shargi sp. nov. by the distinct colour pattern of abdominal sterna, namely E. ( C. ) bicolliculatus ( Hrivniak et al. 2017: 356, figs 7-9), E. ( C. ) alpestris (Braasch, 1979: 284, fig. 1d), E. (C.) alborzicus sp. nov., (Fig. 1B, K-M ), E. ( C. ) caucasicus , E. ( C. ) iranicus ( Braasch 1979: 284, fig. 3b), E. (C.) nigripilosus ( Sinitshenkova 1976: 89, fig. 28), E. ( C. ) znojkoi (Braasch, 1980: 172, 4b), and E. (C.) zagrosicus sp. nov. (Fig. 5B, K ).

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 3. Epeorus (Caucasiron) shargi 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-K colouration of abdominal terga L colouration of abdominal sterna.

Figure 4. Epeorus (Caucasiron) shargi 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 abdominal segments VIII-X I sternum IX, female J sternum IX, male K gill VII (flattened on slide) L gill VII (in natural position from ventral view).

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 9. Distribution of Epeorus (Caucasiron) species in northern Iran. Colour of symbols shows the occurrence of species: red - E. (C.) alborzicus sp. nov., light blue - E. (C.) shargi sp. nov., violet - E. (C.) cf. znojkoi, black - E. (C.) iranicus, yellow - E. (C.) nigripilosus. The letter H shows the localities of holotypes. Black symbols with white cross show unrevised records of E. (C.) iranicus.

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.