Cincticostella funki Martynov, Selvakumar, Palatov & Vasanth, 2021

Martynov, Alexander V., Selvakumar, C., Palatov, Dmitry M., Subramanian, K. A., Sivaramakrishnan, K. G., Vasanth, M. & Jacobus, Luke M., 2021, Overview of Indian and Nepali representatives of the Cincticostella nigra (Ueno, 1928) complex (Ephemeroptera, Ephemerellidae), with discussion about Cincticostella Allen, 1971 species complexes, ZooKeys 1040, pp. 123-166 : 123

Cincticostella funki Martynov, Selvakumar, Palatov & Vasanth sp. nov. Figs 9 , 10 , 11 , 12

Description.

Larva. Late instars: body length 10.5-11 mm; caudal filaments length 6-7 mm. Body robust, yellowish-brown, abdomen darker (Fig. 9A ). Head, thorax and abdomen with longitudinal medial white line; on abdomen line is most broad (Figs 9A-C , 12A, C ). Anterolateral projections of mesothorax and lateral areas of pronotum are yellowish-whitish. Pronotum and mesonotum with indistinct whitish - yellowish spots.

Head: Without tubercles and ridges. Genae rounded, moderately developed (Fig. 9B ). Mouthparts (Fig. 10A-F ): Anteromedian emargination of labrum shallow and narrow (Fig. 10C ). Anterolateral angles of labrum rounded. Dorsal surface of the labrum covered mainly with long, thin and stout hair-like setae; setae decreasing in length towards central notch. In addition, setae with feathered margins, small hair-like setae and solitary empty scale sockets presented on labrum surface. Largest hair-like setae and their greatest number on mandibles situated in the centre of their outer margin and adjacent areas (Fig. 10A and B ). Additionally, mandibles bearing few empty scale sockets. Prostheca consisting of protuberance with tuft of middle-sized, hair-like setae. Planate mandible with row of long thick hair-like setae (7-8) under mola and tuft of short or middle-sized hair-like setae above; outer and inner incisors (kinetodontium) with three teeth. Angulate mandible with few short hair-like setae at the end of mola; outer incisor apex with four teeth; inner incisor with four teeth, two central teeth distinctly larger. Apices of superlinguae rounded, bearing long, thin and stout, hair-like setae; surfaces of lingua covered with thin hair-like setae (Fig. 10D ). Lingua with shallow medial concave on anterior margin. Surface of lingua with irregular, subtransverse to longitudinal axis of the body, rows of short, pointed, stout setae (8-9). Maxilla with two dentisetae; their inner margins serrated. Apical part of maxilla densely covered with long, stout hair-like setae (Fig. 10E ). Inner margin of galea-lacilia with a dense row of stout hair-like setae, longest setae situated proximal. In addition, a group of 16-24 long, stout setae situated on surface of galea-lacilia base. Maxillary palp long, 3-segmented, with distinct articulation (Fig. 10E ). Segment III elongated with several fine setae, bluntly pointed apically. Segments I and II subequal in a length, covered mainly with a long, stout hair-like setae. Labium robust, glossae rounded; labial palp 3-segmented (Fig. 10F ). Segments I and II flattened, subequal in length; on dorsal surfaces of segments stout setae (long, hair-like) present mainly near margins; ventral surfaces, outer and inner margins of segments densely covered with long, stout, hair-like setae; central part of dorsal surface near inner margin on segment I with scale sockets with feathery setae. Segment III narrow, elongated (length/width ratio = 2.5-2.7), with rounded apex, covered with short fine setae. Whole ventral surface of labium covered mainly with long, stout, hair-like setae; dorsal surface of glossae and apices of paraglossae covered mainly with similar kind of setae.

Thorax: Dorsal surface of thorax covered with scattered mainly short, waved and hooked, stout hair-like setae (Fig. 23B ). Pronotum expended laterally; anterolateral projections broad, small and rounded (Fig. 9C ). Anterolateral projections of mesothorax well-developed, with rounded posterior angles, outer margins not notched and not subparallel to lateral aspect of body (on slide with immature larva - subparallel) (Fig. 9C, D ). Thoracic surface without any distinct ridges and tubercles. In mature larvae, paired posterior projections between fore wing pads small, rounded with narrow cleft between them; apical parts of outer margins of projections not pressed against wing pads (Fig. 9C ).

All femora slightly flattened (length/width ratio = fore femur 2.0-2.1; middle femur 2.0-2.2; hind femur 2.0-2.2) (Fig. 11A-C ), each one with longitudinal ridge, especially visible on middle and hind femora. Average length ratio of leg’s parts (femora: tibia: tarsi): foreleg 1.48: 1.43: 1.00; middle leg 1.61: 1.72: 1.00; hind leg 2.10: 2.32: 1.00. All femora outer margins without apical projections, any distinct serration also absent.

Whole dorsal surface of fore femur covered with scattered middle-sized, hair-like setae and scale sockets with small scales in some of them; basal part of surface with group of spine-like setae, bifurcated, stout setae and stout, hair-like setae. Additionally, numerous long, bifurcated apically, stout setae covering dorsal surface of fore femora along basal half of its inner margin. Distal part of surface with relatively wide, transverse, band consisting of irregular, sparse rows of different-sized (mainly long), rounded apically (only sometimes bluntly pointed with shallow bifurcation of apex), stout setae; some of setae situated on chalazae (Fig. 11D ). Outer margin of fore femur and dorsal surfaces along it covered with different-sized stout setae with long rounded and bifurcated apices and numerous middle-sized hair-like setae. Inner margins of fore tibia and tarsus and dorsal surfaces along those margins densely covered with spine-like setae and stout, hair-like setae. Dorsal surface of fore tibia also with row of long, pointed thick setae, stout setae and scattered hair-like setae. Outer margin of fore tibia and tarsus with few hair-like setae only (solitary and in tufts).

Dorsal surface of middle and hind femora covered with few scattered hair-like setae and scale sockets with small scales in some of them; also, surface covered with numerous short, rounded apically, stout setae (Fig. 11B, C ). Inner margins of middle and hind femora without stout setae, only solitary hair-like setae present. Outer margins of middle and hind tibiae with moderately dense irregular rows of mainly long and pointed, stout setae and few hair-like setae amongst them.

Inner margins of middle and hind tibiae and tarsi densely covered with spine-like setae and stout, hair-like setae; inner margins of middle and hind tibiae also with long, pointed and stout setae. Outer margin of middle and hind tibiae with irregular row of long, pointed and bifurcated, stout setae. Outer margin of middle and hind tarsi with hair-like setae (solitary and in tufts) only.

Ventral surfaces of all tibiae and tarsi with hair-like setae (solitary and in tufts) and long, thin, pointed, stout setae; stout setae situated in apical parts of tibiae and tarsi and along their inner margins.

Tarsal claw of all legs hooked, with two (rarely three) denticles distanced from each other; basal denticle (rarely two denticles) distinctly larger; distal denticle directed angled forward (Fig. 11E ); claw also bears several subapical setae.

Abdomen: Posterior margins of tergum I with thin and stout, hair-like setae only; several similar setae present on surface of tergum I. Submedian areas of terga II-IX surfaces, posterior margins of terga VIII-X (excluding central area between submedian projections) and all paired submedian projections covered with small and middle-sized, oval or, sometimes, with slightly divergent margins, stout setae with rounded apices. Additionally, all terga surfaces covered with scattered, small, stout hair-like setae, short, thin, hair-like setae, scale sockets and short scales in some of them. Sterna covered with scattered thin and stout, hair-like setae and scale sockets.

Pairs of pointed, not bifurcated, projections present on abdominal terga II-IX; those on terga V-VIII strongest; those on terga II-IV distinctly smaller than others (Fig. 12A-C ). Posterior margin of tergum X smooth, without projections. Abdominal segments IV-IX with posterolateral projections; on segment IX, they are most developed and directed backwards and laterally. Posterior margins of terga VIII-X with rows of short, stout setae with rounded apices (these setae almost absent in central areas of the margins). Lateral margins of terga IV-VIII covered with small stout setae with apices rounded.

Dorsal surface of abdominal gills covered with scattered hair-like setae and scale sockets; shape of gills as in Fig. 12D-G ; medial, transverse band of weakened membrane absent on gill III.

Caudal filaments subequal in length, with mainly elongated, rounded apically, stout setae and hair-like setae at articulations.

Adults.

Unknown.

Etymology.

The new species is named in honour of Dr. David Funk (Stroud Water Research Center, USA), who contributed significantly to the study of Ephemerellidae .

Diagnosis.

The species is morphologically close to C. shinichii sp. nov. (see below), but can be distinguished from this species and other representatives of the complex by the following combination of the characters: (i) genae rounded and moderately developed (Fig. 9B ); (ii) anteromedian emargination of labrum shallow and narrow (Fig. 10C ); (iii) maxillary palp well-developed (Fig. 10E ); (iv) segment III of maxillary palp elongated, rounded apically (Fig. 10E ); (v) anterolateral projections of prothorax small, broad and rounded (Fig. 9C ); (vi) mesothoracic anterolateral projections well-developed, with rounded posterior angles, outer margins not notched and not subparallel to lateral aspect of body (on slide with immature larva - subparallel) (Fig. 9C, D ); (vii) surface of thorax covered with scattered mainly short, waved and hooked, stout hair-like setae (Fig. 23B ); (viii) fore femur with relatively wide, transverse band consisting of irregular, sparse rows of different-sized (mainly long), rounded apically (only sometimes bluntly pointed with shallow bifurcation of apex), stout setae (Fig. 11A, D ); (ix) tarsal claw with two denticles distanced from each other; basal denticle distinctly larger; distal one directed angled forward (Fig. 11E ); (x) pairs of pointed projections present on abdominal terga II-IX; those on terga II-IV distinctly smaller than others; projections on tergum IX elongated and distinctly pointed; posterior margin of tergum X without paired projections (Fig. 12A-C ).

Distribution.

Northern India and the India-China border region (Uttarakhand State and Arunachal Pradesh).

Habitat.

In Arunachal Pradesh, larvae of C. funki sp. nov. were collected from the Rike River (type locality) (2-5 m wide) at intermediate high mountain areas, on the Eastern Himalayan Range (Fig. 24B ). Apparently, they prefer lotic water bodies with relatively low water temperature (9 °C-10 °C in sampling period), average current velocity (0.4-0.7 m/s), the bottom of river containing pebbles, cobbles and low level of silt particles and there is a median degree of anthropogenic pressure. Rivers inhabited by the species can be characterised as oligosaprobic. Larvae were collected from silted gravel and cobbles. Larvae of the mayfly Baetis sp., stoneflies Nemouridae and Peltoperlidae and caddisflies Himalopsyche sp. and Rhyacophila sp., were registered in the microhabitats along with C. funki sp. nov.

In Uttarakhand State, larvae of C. funki sp. nov. were collected from a small river (2-4 m wide) in medium high mountains, on the southern slope of the Great Himalayan Range (Fig. 24C ). Apparently, they prefer small lotic waterbodies with relatively low water temperature (12 °C in sampling period), average current velocity (0.3-0.6 m/s), mosaic bottom and low degree of anthropogenic pressure. Rivers inhabited by the species can be characterised as oligosaprobic. Larvae were collected from silted gravel of the mayfly Caenis sp., stoneflies Mesonemoura sp. and Kamimuria sp. and the caddisfly Lepidostoma sp.

Type material.

Holotype: India: larva, Arunachal Pradesh, Papumpare District, vicinity of Parang Village, Rike River, 27.32797°N, 93.50308°E, h ~1285 m a.s.l., 14.xii.2018, Coll. Bikramjit Sinha - IN ZSI/SRC-I/E-512 [ZSI]. Paratypes: India: one larva, same data as holotype - IN ZSI/SRC-I/E-513 [ZSI]. One larva (on slide 632), Uttarakhand, Almora District, 2nd order left tributary of Ramganga River (in Dwarahat forest, 10.1 km north-eastwards of Chaukhutia Town), 29.925608 N, 79.445983 E, h ~ 1200 m a.s.l., 2.ii.2011, Palatov D.M. leg. - IN Indi1Cinsp [NMNH NASU].

Figures

Figure 9. Larva of Cincticostella funki Martynov, Selvakumar, Palatov & Vasanth sp. nov., holotype (A) and paratype (B-D) A habitus, dorsal view, scale bar 2 mm B head C thorax D anterolateral projection of mesonotum.

Figure 10. Larva of Cincticostella funki Martynov, Selvakumar, Palatov & Vasanth sp. nov., paratype A angulate mandible B planate mandible C labrum D hypopharynx E maxilla F labium.

Figure 11. Larva of Cincticostella funki Martynov, Selvakumar, Palatov & Vasanth sp. nov., paratype A fore femur B middle femur C hind femur D stout setae of dorsal surface of fore femur E tarsal claw.

Figure 12. Larva of Cincticostella funki Martynov, Selvakumar, Palatov & Vasanth sp. nov., holotype (A-C) and paratype (D-G). A abdomen, dorsal view B paired submedian projections of terga VI-VIII, lateral view C paired submedian projections of terga V-IX, dorsal view D-G gills III-VI.

Figure 23. Setae on dorsal surface of thorax of some representatives of Cincticostella nigra (Ueno, 1928) complex A dominant kind of stout setae - numerous small stout setae with divergent margins, bifurcated apices B dominant kind of stout setae - short, waved and hooked, stout hair-like setae C dominant kind of stout setae - scattered short, relatively strait, stout hair-like setae.

Figure 24. Habitats of Cincticostella changfai Martynov & Palatov, sp. nov. (A) and Cincticostella funki Martynov, Selvakumar, Palatov & Vasanth sp. nov. (B and C). A Ramganga River (300 m above Patangoari Village), Uttarakhand State, Almora District, India B Rike River (vicinity of Parang Village), Arunachal Pradesh, Papumpare District, India C second order left tributary of the Ramganga River (10.1 km north-eastwards of Chaukhutia Town), Uttarakhand State, Almora District, India.