Cincticostella ranga Selvakumar & Subramanian, 2019

Martynov, Alexander V., Selvakumar, C., Subramanian, K. A., Sivaramakrishnan, K. G., Chandra, Kailash, Palatov, Dmitry M., Sinha, Bikramjit & Jacobus, Luke M., 2019, Review of the Cincticostella insolta (Allen, 1971) complex (Ephemeroptera: Ephemerellidae), with description of three new species from northern India and Nepal, Zootaxa 4551 (2), pp. 147-179 : 160-163

Cincticostella ranga Selvakumar & Subramanian , sp. nov.

( Figs 53–73 )

Larva. Late instar: body length 5.5–6.0 mm. Caudal filaments 2.5–3.0 mm. Body yellowish brown ( Fig. 53 ). All body surfaces, labrum, mandibles, labium and gills densely covered with large scales sockets and small scales in some of them ( Figs 58–60, 64–68 ).

Head: With two pairs of small blunt protuberances; genae not expanded ( Fig. 54 ). Mouthparts: Labrum wide, angles rounded; anteromedian emargination shallow, dorsal surface densely covered with long, hair-like setae; ventral surface with numerous stout, hair-like setae; anterior margin with numerous feathered setae ( Fig. 60 ). Mandibles with numerous long, hair-like setae on dorsal and lateral surfaces. Left mandible with outer incisor consisting of three denticles, outer denticle longer than others; inner incisor pointed, with two distinct central denticles and one small, blunt lateral denticle ( Fig. 59 ); prostheca consisting of bunch of hair-like setae ( Fig. 59 ). Right mandible with outer incisor trifurcated and inner incisor bifurcated; prostheca consisting of bunch of hairlike setae; row of 8 or 9 long, stout hair-like setae present below mola ( Fig. 58 ). Anterior margins of superlinguae densely covered with stout, hair-like setae; dorsal and ventral surfaces in apical half with fine setae and variously sized, stout, hair-like setae; lingua convex medially, with fine setae on dorsal and ventral surfaces; rows of several short, pointed, stout setae on lingua surface near base ( Fig. 61 ). Maxilla with two dentisetae ( Fig. 63 ); dense patches of long, stout, hair-like setae on apex, some setae with serrated inner margins; inner surface of galea-lacinia with row of long, stout, hair-like setae; group of several long, feathered, stout setae present near base of galealacinia. Maxillary palp 3-segmented, with several relatively long, hair-like setae; segment III distinctly narrowed and bluntly pointed ( Figs 62, 63 ); segmentation weakly developed. Labium with small, almost round glossae; dorsal surface of glossae and apexes of paraglossae with long, stout, hair-like setae. Inner margins of paraglossae rounded, not subparallel to longitudinal axis of body; paraglossae not held particularly tightly against glossae ( Fig. 64 ). Labial palp 3-segmented, segment I length subequal to segment II; segments I and II with middle-sized and long, hair-like setae on margins and surfaces; outer margin of segments I and II and dorsal surfaces of segment II also with spine-like setae; segment III much thinner than other segments and rounded apically, with few fine setae. Ventral surface of mentum and submentum with hair-like and fine setae ( Fig. 64 ).

Thorax: Surface with few indistinct ridges and tubercles. Pronotum with anterolateral angles projecting anteriorly ( Figs 56, 57 ). Mesothorax with pair of bluntly pointed posterior projections between forewing pads; anterolateral projections not notched, with margins subparallel to lateral aspect of body or somewhat rounded ( Figs 53, 55 ).

Femora of all legs at least somewhat flattened, with those of mid- and hindlegs most flattened. Femora of all legs longer than tibiae, and tibiae longer than tarsi. Outer margin of forefemur with hair-like setae and various stout setae of different lengths, some pointed and some rounded at apex. Inner and outer margins of forefemur without serration, but sometimes with one or two indistinct chalazae on outer margin ( Fig. 65 ). Dorsal surface of forefemur with numerous chalazae bearing apically rounded, stout setae ( Figs 65, 68 ). Fore tibia with hair-like setae (solitary and in bunches) on both outer and inner margins; inner margin of fore tibia also with sparse row of spine-like setae; dorsal surface of fore tibia with hair-like setae (solitary and in bunches) and sparse row of spine-like setae. Inner margin of fore tarsus with thin, hair-like setae and dense row of stout, hair-like setae, spine-like setae and feathered, stout setae; outer margin of fore tarsus with hair-like setae only. Midfemur flattened mostly in distal half; outer margin slightly serrated ( Fig. 66 ), with pointed or apically rounded, stout setae and numerous hair-like setae of various lengths. Outer margin of midfemur without apical projection. Inner margin of midfemur without serration. Hindfemur flattened ( Fig. 67 ); outer margin serrated (serration not deep), with long, hair-like setae and short, apically rounded, stout setae. Inner margin of hindfemur without serration. Apical projection of hindfemur outer margin small. Outer and inner margins of mid- and hind tibiae with hair-like setae (solitary and in bunches) and row of elongated, spine-like setae. Distal ends of inner margins of tibiae with groups of spine-like setae and elongated, feathered, stout setae. Outer margins of mid- and hind tarsi with hair-like setae (solitary and in bunches); inner margins of tarsi with hair-like setae (solitary and in bunches) and rows of elongated, stout, hair-like setae and spine-like setae.

Tarsal claw distinctly hooked ( Fig. 69 ), with 2 subequal denticles and sometimes third, much smaller denticle near others, and with several subapical setae.

Abdomen: Paired projections present on terga II–IX, not bifurcated. Dorsal lamellae of gills III–V similar in shape; gill III without medial transverse band of weakened membrane; gill VI not wide and elongated compared to gills III–V ( Figs 70–73 ); gill VII very small and entirely covered by gill VI. Gill socket VII located near posterolateral corner. Caudal filaments with apically pointed, stout setae at articulations; setae shorter than corresponding segment.

Adult. Unknown.

Etymology. This species is named after the type locality, Ranga River in Arunachal Pradesh State.

Diagnosis. This species can be distinguished from other Cincticostella species by the following combination of characters: (i) genae moderately developed ( Fig. 54 ); (ii) inner margins of paraglossae rounded, not subparallel to longitudinal axis of body; paraglossae not held particularly tightly against glossae ( Fig. 64 ); (iii) anterolateral angles of pronotum with projections directed forward ( Figs 56, 57 ); (iv) anterolateral projections of mesothorax not notched, with margins usually subparallel to lateral aspect of body or somewhat rounded ( Figs 53, 55 ); (v) forefemur without serration on inner and outer margins ( Fig. 65 ); (vi) dorsal surface of forefemur with numerous chalazae bearing apically rounded, stout setae ( Figs 65, 68 ); (vii) hindfemur distinctly flattened in distal part ( Fig. 67 ); (viii) outer margins of mid- and hindfemora with shallow serration, and their inner margins without serration ( Figs 66, 67 ,); (ix) middle femur without apical projection ( Fig. 66 ); (x) all pairs of abdominal tergal projections not bifurcated ( Fig. 53 ); (xi) tarsal claw with 2 or 3 denticles ( Fig. 69 ).

Distribution. Known only from India ( Fig. 153 ). Habitat. Cold, fast-flowing streams with cobble and gravel ( Figs 151, 152 ). Type material. INDIA: Holotype: larva, Arunachal Pradesh, Lower Subansiri District, Talle Valley, 27.537201 N, 93.959883 E, h ~ 2370 m, 14-IV-2015, K.A. Subramanian— Reg. No. 5576/H13. Paratypes: 5 larvae, same data as holotype; 3 larvae, Arunachal Pradesh, Lower Subansiri District, Ranga River, 27.396404 N, 93.757378 E, h ~ 625 m, 21-IV-2015, K.A. Subramanian & Bikramjit Sinha— Reg. No. 5577/H13.

Figures

FIGURE 153. Map of distribution of the Cincticostella insolta complex representatives: a.—Cincticostella richardi sp. nov.; b.—Cincticostella sivaramakrishnani sp. nov.; c.—Cincticostella ranga sp. nov.; d.—Cincticostella bifurcata Xie, Jia, Chen, Jacobus & Zhou, 2008; e.—Cincticostella insolta (Allen, 1971); f.—Cincticostella braaschi Jacobus & McCafferty, 2008; g.— Cincticostella femorata (Tshernova, 1972). Note: Distributions of C. insolta and C. femorata in mainland China mentioned by Xie et al. 2009 could not be given on the map, due to insufficient data.

FIGURES 53–57. Larva of Cincticostella ranga sp. nov., paratypes: 53.—dorsal habitus; 54.—head; 55.—projection of mesothorax; 56, 57.—anterolateral projections of pronotum. Scale bar: 53.—2 mm; 54–57.—0.5 mm.

FIGURES 58–64. Larva of Cincticostella ranga sp. nov., paratypes: 58, 59.—mandibles; 60.—labrum; 61.—hypopharynx; 62.—maxillary palp; 63.—apical part of maxilla; 64.—labium. Scale bar: 58–61, 64.—0.5 mm; 62.—0.1 mm; 63.—0.25 mm.

FIGURES 65–73. Larva of Cincticostella ranga sp. nov., paratypes: 65.—forefemur; 66.—middle femur; 67.—hind femur; 68.—stout setae on dorsal surface of forefemur; 69.—claw; 70–73.—gills III–VI. Scale bar: 65–67.—1 mm; 69.—0.2 mm; 70– 73.—0.5 mm.

FIGURES 147–152. Collection localities of Cincticostella richardi sp. nov. (147, 148), Cincticostella sivaramakrishnani sp. nov. (149, 150) and Cincticostella ranga sp. nov. (151, 152): 147.—Alaknadra River (800 m a.s.l.); 148.—Pindar River (780 m a.s.l.) (C. richardi sp. nov. type locality); 149, 150.—Modi River (1550 m a.s.l.) (C. sivaramakrishnani sp. nov. type locality); 151.—Talle Valley (2370 m a.s.l.) (C. ranga sp. nov. type locality); 152.—Ranga River (625 m a.s.l.).