Dannella daurica, Tiunova, 2023

Tiunova, Tatiana M., 2023, New Species and First Record of Dannella Edmunds 1959 (Ephemeroptera: Ephemerellidae) from the Eastern Palaearctic, Zootaxa 5227 (3), pp. 378-388 : 378-387

publication ID	https://doi.org/ 10.11646/zootaxa.5227.3.6
publication LSID	lsid:zoobank.org:pub:816FB8DC-9FA1-464A-9585-2584A2FAE9E2
DOI	https://doi.org/10.5281/zenodo.7525474
persistent identifier	https://treatment.plazi.org/id/03F68788-FF9A-1623-56E5-F94631E7F059
treatment provided by	Plazi
scientific name	Dannella daurica
status	sp. nov.

Treatment

Dannella daurica sp. nov.

Figures 1–31 View FIGURES 1–2 View FIGURES 3–8 View FIGURES 9–13 View FIGURES 14–17 View FIGURES 18–24 View FIGURES 25–27 View FIGURES 28–31

Material. HOLOTYPE: male larva, RUSSIAN FEDERATION, Amurskaya Oblast, Amur River basin, Talali River , tributary Belaya River , 51.541111° N 127.271944° E, 21.VII.2006, T. Tiunova GoogleMaps . Paratypes: one larva, same data as holotype GoogleMaps ; 3 larvae, middle age, Khabarovskiy Kray , Bureinskiy district , Sinel’ River, bridge, 7 km lower Talakan village, 50.241405° N 130.181227° E, 4.VII.2014, T. Tiunova GoogleMaps .

Description. Mature larva. Length (mm): body 5.6–5.7; cerci and paracercus 2.5–3.3. General body color light brown to brown with slightly pronounced maculation ( Figs 1–2 View FIGURES 1–2 ).

Head: brown with dark marking on vertex; frons and lateral margins with long hairlike setae; antennae brownish ( Figs1–2 View FIGURES 1–2 ).

Mouthparts. Labrum wide, rectangular (width/length ratio of 1.9 – 2.0), anterior margin with shallow emargination medially and with cilialike setae; dorsal surface with long, stout and fine hairlike setae and pores; lateral margins with long setae ( Fig. 3 View FIGURES 3–8 ). Incisor of right mandible with two blunt and rounded teeth, one about two times wider than other ( Figs 4–5 View FIGURES 3–8 ); group of long setae under mola ( Fig. 4 View FIGURES 3–8 ); incisor of left mandible with five rounded teeth, third one largest ( Figs 6–7 View FIGURES 3–8 ); basal area of mandibles with long, fine, hairlike setae and pores; area near mola serrated ( Figs 7–8 View FIGURES 3–8 ). Maxillary palp 3-segmented, well developed; first and third segments relatively equal length; second segment 2.5 times shorter than first and third segments ( Figs 9 – 10 View FIGURES 9–13 ); tip of third segment with short apical spine ( Fig. 11 View FIGURES 9–13 ); group of 9 – 10 long setae situated on inner side of maxilla ( Fig. 9 View FIGURES 9–13 ); lateral margins of maxilla with long fine hairlike setae. Paraglossae slightly shorter than glossae; surface of segments I and II of labial palps with long hairlike setae ( Fig. 12 View FIGURES 9–13 ); third segment smallest, conical, rounded apically, with short stout blunt setae more numerous on apex ( Fig. 13 View FIGURES 9–13 ).

Thorax. Pronotum brown or light brown with lighter lateral margins. Mesonotum brown or light brown ( Figs 1 –2 View FIGURES 1–2 ). Surface of thorax densely covered with pores ( Figs 19 – 20 View FIGURES 18–24 ). All legs yellowish ( Figs 1 – 2 View FIGURES 1–2 ). Femora of legs broadened slightly. Fore femur with transverse row of long, stout and pointed setae in mid-region; length of these setae ½ of width of femur ( Fig. 14 View FIGURES 14–17 ); inner margin of femur with row of long hairlike setae and small pointed setae; outer margin with long hairlike setae, length equal to width of femur; basal area with group of setae of various types and sizes: elongated setae widening and blunt apically, and short pointed setae ( Fig. 15 View FIGURES 14–17 ). Tibiae and tarsi with regular rows of stout, pointed setae on inner margins and with hairlike setae on outer margins ( Fig 14 View FIGURES 14–17 ). Femur of middle leg with small, spatulate setae and long hairlike setae on inner margin; regular row of pointed setae along margin; mid-region with regular row of 5 – 6 spatulate setae ( Fig. 16 View FIGURES 14–17 ). Tibia and tarsi with hairlike setae on outer margins; on inner margins setae not numerous; distal margins of tarsi with 4 – 5 blunt setae. Dorsal surface all legs densely covered small with scale-like setae ( Fig. 15 View FIGURES 14–17 ). Claws without denticles ( Fig. 17 View FIGURES 14–17 ).

Lengths (mm) of leg segments. Fore leg: femur 0.8–0.9; tibia 0.55–0.6; and tarsus 0.55–0.6. Middle leg: femur 0.9; tibia 0.5–0.6; and tarsus 0.55–0.6. Hind leg: femur 0.9–1.0; tibia 0.6; and tarsus 0.5–0.55. Ratio of width to length of fore femur 0.38–0.39; middle femur—0.33–0.34, hind femur—0.30.

Abdomen. Tergites brown or light brown without maculation, lateral margins lighter. Tergum X lighter than others; tergites IV–VI with dark brown stripe at gills attachment ( Figs 1 View FIGURES 1–2 , 18 View FIGURES 18–24 ). All surfaces of tergites covered by small, stout, pointed setae ( Fig. 19 View FIGURES 18–24 ); posterior margins of tergites IV–IX with sparse row of spatulate setae ( Fig. 20 View FIGURES 18–24 ); tergites II–III without posterolateral projection ( Figs 1–2 View FIGURES 1–2 , 18 View FIGURES 18–24 ); posterolateral projection of tergites IV–IX well developed ( Figs 1–2 View FIGURES 1–2 , 25 View FIGURES 25–27 ); densely covered with strong, long and middle hairlike and spatulate setae of various sizes ( Figs 21–22 View FIGURES 18–24 ). Sternites yellowish without maculation; surfaces covered with scattered spatulate setae ( Fig. 26 View FIGURES 25–27 ). Gill I filament-like ( Figs 1 View FIGURES 1–2 , 18 View FIGURES 18–24 ); gill IV wide, slightly tapering distally; distal margin with shallow notch in middle part and rounded protrusion on outer side ( Fig. 28 View FIGURES 28–31 ); gills V and VI of same shape with strongly attenuated, rounded distal margin ( Figs 29–30 View FIGURES 28–31 ); gill VII subtriangular, with rounded distal margin ( Fig.31 View FIGURES 28–31 ); gills IV and VI subequal in length; gill V smaller then gills IV and VI; gill VII very small, covered by gill VI. Cerci and paracercus yellowish, of same length; brownish bands present on basal part of filaments ( Fig. 27 View FIGURES 25–27 ).

Diagnosis. Larva. Maxillary palp 3-segmented, well developed; first and third segments relatively equal length; second segment of maxillary palp 2.5 times shorter than first and third segments ( Figs 9–10 View FIGURES 9–13 ); third segment of labial palps smallest, conical, rounded apically, with short stout blunt setae more numerous on apex ( Figs 12–13 View FIGURES 9–13 ); fore femora with transverse row of long, stout and pointed setae in mid-femora; the length of the setae is ½ of the width of the femora ( Fig. 14 View FIGURES 14–17 ); claws without denticles ( Fig. 17 View FIGURES 14–17 ); tergites II–III without posterolateral projection ( Figs 1–2 View FIGURES 1–2 , 18 View FIGURES 18–24 ); posterolateral projection of tergites IV–IX well developed ( Figs 18 View FIGURES 18–24 , 25 View FIGURES 25–27 ); gills on segment I consist-ing of a single filament ( Fig. 1 View FIGURES 1–2 , 18 View FIGURES 18–24 ); gill IV wide, slightly tapering by distally; distal margin with a shallow notch in middle part and rounded protrusion on the outer side ( Fig. 28 View FIGURES 28–31 ).

Distribution. Dannella daurica sp. nov. is known from two habitats in the Far East of Russia: Amurskaya oblast’ and Khabarovskiy Kray ( Figs 32 –33 View FIGURES 32–33 ). The larvae of the new species were found in relatively slow flow and in gravel-sand substrate. Water temperature was 17.8 – 22.0°C, depth 50 – 70 cm. The width of the rivers in the places of collection of larvae does not exceed 10 m; the length of these rivers is up to 50 km.

Etymology. The name of the new species is associated with its habitat (Amur River basin, the Bureya River basin), located in the Daurian botanical-geographical region.

Discussion. Among species of Dannella with available larvae description, Dannella daurica sp. nov. differs from the Nearctic species Dannella lita and D. provonshai by the absence of posterolateral processes on abdominal segment III ( Figs 1 – 2 View FIGURES 1–2 , 18 View FIGURES 18–24 ). In D. lita , posterolateral processes of segment III are well-developed ( McCafferty 1977: Fig. 17 View FIGURES 14–17 ); in D. provonshai segment III has small, rounded posterolateral processes ( McCafferty 1977: Fig. 18 View FIGURES 18–24 ). By the absence of posterolateral processes on the third abdominal segment, Dannella daurica sp. nov. is similar to D. simplex , but can be distinguished by the following features: (1) General body color light brown without visible maculation ( Figs 1 – 2 View FIGURES 1–2 ); in D. simplex general color tan to brown with dark brown marks on abdominal dorsum (Burks 1953). (2) Fore femora broadened slightly; the ratio of width to length is 0.38–0.39 ( Fig. 14 View FIGURES 14–17 ); in D. simplex the ratio of width to length is 0.42–0.44 (David Funk, unpublished).