Cincticostella tornata Auychinda & Gattolliat, 2020

Auychinda, Chonlakran, Muranyi, David, Li, Weihai, Sartori, Michel & Gattolliat, Jean-Luc, 2020, A new species of Cincticostella (Ephemeroptera, Ephemerellidae) from China, Alpine Entomology 4, pp. 129-138 : 129

Cincticostella tornata Auychinda & Gattolliat sp. nov.

Material.

Holotype: China • Larva; Shaanxi, Hanzhong city, Foping county, Qinling Mts, slow forest brook in Panda valley; Alt. 1330m. 33°40.368'N, 107°58.327'E; 20 Apr. 2018; Coll. W.H. Li, R.R. Mo, D. Murányi; MZL GBIFCH 00763636.

Paratypes: China • 5 larvae; same data as for holotype; 2L in alcohol GBIFCH 00673084; 1L on slide GBIFCH 00606852; 1L on slide used for DNA extraction GBIFCH 00654874 all deposited in MZL. 1L in alcohol deposited in HNHM. 1L in alcohol deposited in HIST.

Description.

Larva: Body length 8.7-10.0 mm; caudal filaments length 8.0-9.0 mm. Body yellowish-brown.

Head: Covered with thin setae. One pair of small, rounded protuberances between eyes. Genae quadrangular, well developed, angles rounded (Fig. 1 ). Antennae with scapus short, pedicellus as broad as long, flagellum of about 25 segments, first segment as long as next three segments.

Mouthparts: Labrum wide, apicolateral angle rounded; apicomedial emargination shallow, dorsal surface densely covered with long, hair-like setae and long stout flattened setae scattered over surface (Fig. 2A ); ventral surface with numerous, long, stout, hair-like setae laterally orientated; apical margin with numerous feathered setae and very thin hair-like setae (Fig. 2B ). Mandibles with numerous, hair-like setae on 2/3 proximal of dorsal and lateral surfaces (Figs 2C, D ). Left mandible: outer incisor composed of three teeth, two outer teeth stout, broad, apically rounded and one small, blunt tooth; inner incisor with one main stout, apically pointed tooth and one inner vestigial tooth; stout rectangular prostheca with bunch of hair-like setae on inner side (Fig. 2E ). Right mandible: outer incisor composed of two spoon-shaped teeth, outer tooth longer than inner; inner incisor composed of two apically pointed teeth, orientated perpendicularly to outer incisor; prostheca consisting of numerous hair-like setae (Fig. 2F ); eight hair-like setae on margin below mola (Fig. 2D ). Maxilla: apex with transformed ventral canine typical of genus ( Kluge 2004); two dentisetae with serrated inner margin; apex of maxilla surface with numerous, long, stout, hair-like setae, some with serrated inner margin; inner margin of galealacinia with 3-4 rows of long, stout, simple setae; 10-12 feathered, stout setae roughly arranged in a row near base of galealacinia surface (Fig. 2G, H ). Maxillary palp: three segmented; segments partially fused; segment I slightly longer than half of segments II and III combined; segment III short, pointed, with few thin setae on apex (Fig. 2G, H ). Labium with glossae semicircular, almost two times longer than broad; ventral surface of glossae covered with long, stout, simple setae; dorsal surface with an arc of long simple setae parallel to outer margin; glossae protruding over apices of paraglossae; paraglossae semicircular, dorsal surface covered with numerous long stout simple setae, ventral surface with flame-like setae. Ventral surface of mentum and submentum mostly covered with flame-like setae. Labial palp three-segmented; segments I and II equal in length, covered with long, hair-like setae; segment II crescent shaped, outer margin with spine-like long setae and long hair-like setae, inner margin covered with numerous long thin setae; segment III conical, two times longer than broad at base, apex covered with short thin setae (Fig. 2I ). Hypopharynx: surface of lingua covered with short setae, most abundant in apical part; apices of superlinguae rounded with numerous hair-like setae (Fig. 2J ).

Thorax: dorsal surface covered with scattered small thin setae. Pronotum: broad projection anterolaterally enclosing head, margin rounded except concave apically (black arrow tip on Fig. 3A ); projections covered with long hair-like setae; laterally with short flame-like setae. Mesonotum: broad, large, rounded anterolateral projection, covered with long hair-like setae; laterally with short flame-like setae; small pair of triangular protuberances between forewing pads (white arrow tips on Fig. 3A ). Forelegs: moderately expanded; length ratio of femur: tibia: tarsus = 2.9: 2.4: 1. Forefemora: dorsal surfaces cover with long hair-like setae; dorsal margin slightly concave, with dense setae and with only three blunt chalazae near distal angle; ventral margin with dense setae without serration; apex with one ventral and one dorsal well-developed extension (Fig. 4A ). Foretibiae completely covered with long hair-like setae and short stout setae, apex of ventral margin produced and covered with a bunch of dense, long, thin setae. Foretarsi covered with long hair-like setae, ventral margin with stouter longer feathered setae. Foreclaws hooked with a row of four triangular teeth, two proximal teeth closer to each others (Fig. 4D ). Mid legs: greatly expanded; length ratio of femur: tibia: tarsus = 3: 2.7: 1. Mid femora: dorsal surface cover with hair-like setae; ventral margin with dense setae and four serrated chalazae in proximal half of femora, ending with a well-developed triangular pointed process; dorsal margin with dense setae and eight chalazae progressively larger (Fig. 4B ). Mid tibiae similar to foretibiae except setae less abundant and short flame-like setae on dorsal margin and apically. Mid tarsi: ventral margin with setae not feathered. Mid claws similar to foreclaws. Hind legs: greatly expanded; length ratio of femur: tibia: tarsus = 4.2: 3.2: 1; hind femora similar to mid femora except chalazae of ventral and dorsal margins: ventral margin with three chalazae medially; dorsal margin with 12 chalazae along margin and progressively larger (Fig. 4C ). Hind tibiae and hind tarsi similar to mid tibiae and mid tarsi, respectively. Hind claws similar to foreclaws.

Abdomen: surface of tergites covered with hair-like setae and few stout flame-like setae, absent laterally on tergites IV to IX; distal margin smooth without spines. Tergites I-X with a pair of tubercles, minute on tergites I-III and X (Fig. 4E ); highly developed on tergites IV-IX (Fig. 3B ): arched, acute tubercles covered with medium setae (Fig. 3C ). Sternites densely covered with medium setae; distal margin smooth without spines. Triangular, slender distolateral expansions present on abdominal segments I to IX, highly developed on segments IV to IX, covered with dense flat medium and hair-like setae. Gills present on segments III to VII (Fig. 3E-I ); upper lamellae dorsally densely covered with flame-like setae, upper lamellae of gills III to V subrectangular, of gills VI roughly paddle-like, of gills VII suboval and reduced; lower lamellae bifurcate with marginal processes, bilobed on gills III to V, simple on gills VI and VII. Paracercus subequal in length to cerci; cerci and paracercus densely covered with hair-like setae, apex of each segment with very long, flattened setae (Fig. 3D ).

Adults. Unknown.

Etymology.

The Latin word " tornata " means rounded, in reference to the genae and anterolateral projection of mesonotum.

Diagnosis.

Cincticostella tornata sp. nov. differs from closely related species of the insolta -group by the following combination of characters: 1) glossae protruded beyond apices of paraglossae; 2) genae extended with round apex; 3) anterolateral projection of pronotum pointed with a concave margin; 4) mesothorax with broad, rounded proximolateral expansion; 5) number and degree of development of chalazae on ventral and dorsal margins of mid and hind femora; 6) degree of development of apicoventral projection on ventral margin of fore-, mid and hind femora; 7) apicolateral projection of tergite IX well developed exceeding 1/3 of tergite X.

Distribution.

The new species is only known from the type locality located in the Qinling mountains (Shaanxi province, close to Hanzhong city). This mountain range is considered as a natural boundary between South and North China and between the Palaearctic and Oriental realms (Fig. 5 ). A huge diversity of plant and animals is considered as endemic from this area, among others a subspecies of the giant panda ( Ailuropoda melanoleuca qinlingensis ) and the golden snub-nosed monkey ( Rhinopithecus roxellana ). At our present state of knowledge, it is not possible to know if Cincticostella tornata sp. nov. is endemic to this mountain range or is more widely distributed through China.

Habitat.

The larvae were found in a small forest brook of relatively slow current. Maximum width of the brook is about 1.5 meter; depth varies between 10 and 30 centimetres. The substrate is mostly stony and sandy, mixed with silty patches and a moderate amount of debris. Accompanying fauna included two Holarctic genera of mayflies, Baetis ( Baetidae ) and Ameletus ( Ameletidae ), as well as the stoneflies Rhopalopsole basinigra Yang & Yang, 1995, Spaeronemoura grandicauda (Wu, 1973), Nemoura sp., and two species recently described from the same area, namely Amphinemura albicauda Li, Mo, Dong, Yang & Murányi, 2018 and Amphinemura dingoidea Li, Mo, Dong, Yang & Murányi, 2018 ( Li et al. 2018).

Molecular results.

A sequence of 658 bp, corresponding to the usual fragment of the COI gene, was obtained. The sequence was deposited in GenBank (Accession number: MT254050). It was compared to other known sequences found in databases such as GenBank and BOLD. The closest sequence corresponds to a North America Ephemerellidae ( Drunella walker (Eaton, 1884)) with less than 83% of identity. Around twenty sequences were found with a percentage of identity comprising between 80 and 83, most of them belonging to the families Ephemerellidae and Caenidae . K2P distance was also calculated with a sequence of Cincticostella gosei from Thailand (collected and sequenced by the first author, GenBank accession number: MN186574.1). The distance between the two species was estimated to 21.6% (meaning only 78.4% of identity).

Figures

Figure 1. Cincticostella tornata: A habitus in dorsal view; B habitus in ventral view. Scale bar: 1 mm.

Figure 2. Cincticostella tornata: A dorsal view of labrum; B ventral view of labrum; C left mandible; D right mandible; E left mandibular canine; F right mandibular canine; G maxilla; H crown of maxilla; I labium; J hypopharynx. Scale bars: 0.1 mm (A-D, G-I, J); 0.05 mm (E, F, H).

Figure 3. Cincticostella tornata: A thorax (black arrow tip: concave apical margin of prothorax; white arrow tips: small pair of triangular protuberances between forewing pads); B abdomen; C tergites VI-VII; D cercus; E-I gills of segments III-VII respectively. Scale bars: 1 mm (A, B); 0.25 mm (C-I).

Figure 4. Cincticostella tornata: A forefemur; B mid femur; C hind femur; D forefemur claw; E tergite X. Scale bars: 0.2 mm (A-C); 0.1 mm (D, E).

Figure 5. Map distribution of C. femorata and C. tornata. C. femorata represented by green circle (Gose 1969), blue circle (Tshernova 1972), gray circle (Jacobus 2005) and yellow square (Martynov et al. 2019); C. tornata represented by red triangular. Localities of C. femorata in China are not reported on the map as the species was mentioned from China by Xie et al. 2009 but without further information.