Notacanthurus lamellosus Zhou, 2020

Zhang, Wei, Zhang, Min, Han, Na & Zhou, Chang-Fa, 2020, Two new species of the genus Notacanthurus from China (Ephemeroptera: Heptageniidae, Ecdyonurinae), Zootaxa 4802 (2), pp. 335-348 : 341-345

publication ID

https://doi.org/ 10.11646/zootaxa.4802.2.7

publication LSID

lsid:zoobank.org:pub:41E57AB6-CBA9-490A-9540-20DF787EAD3C

persistent identifier

https://treatment.plazi.org/id/03F3878E-FFD6-FFB9-63B9-077FFBC96C48

treatment provided by

Plazi

scientific name

Notacanthurus lamellosus Zhou
status

sp. nov.

Notacanthurus lamellosus Zhou , sp. n.

Materials examined. Holotype: male imago, Jin-Bian creek (29°20′45.14″N, 110°32′46.36″E), Zhang-Jia-Jie city, Hunan Province, China, collected by Ran LI, Wei ZHANG, 8-VIII-2019. GoogleMaps

Paratypes: 2 male imagoes 3 female imagoes 2 nymphs, same as the holotype; 1 male imago 1 female imago, Jin-Sha village (28°06′30.68″N, 107°41′35.78″E), Zun-Yi city, Guizhou Province, China, collected by Qing-Bo HUO, Jia-Wen YUAN, 6-V-2019 GoogleMaps .

Description. Nymph (in alcohol, Figs 8–11 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 ): body length 7.0– 8.2 mm, caudal filaments 12.0–15.0 mm. Head subquadrate, brown, width 1.6x of length. Anterior margin of head with shallow concavity, lateral margins slightly convex while posterior margin nearly straight; antennae 2.0 mm, four pale dots above the base of antennae and thin pale stripe above compound eyes ( Fig. 8 View FIGURE 8 A–B).

Mouthparts: labrum ca. 0.5x width of head, anteriorly straight, laterally round; dorsally with dense and long hair-like setae, ventral surface with median groove, additional row of bristles on ventral anterior margin ( Fig. 9A View FIGURE 9 ). Mandibles covered with numerous long setae along outer margins; prostheca with 6–7 fimbriate bristles, row of sparse setae below the mola ( Fig. 9 View FIGURE 9 B–C); outer incisor of left mandible with serrated margin; inner one with trifid apex; outer incisor of right mandible with serrated margin and forked apex; inner one divided into 2 sharp denticles ( Fig. 9 View FIGURE 9 B–C, G–H). Maxillae with scattered simple setae on ventral surface and branched distal dentisetae, proximal dentisetae bifid, 16 comb-shaped setae on crown of galea-lacinia ( Figs 9F View FIGURE 9 , 11 View FIGURE 11 A–C); first segment of maxillary palp with sparse setae on both sides; second segment with long and dense setae on outer margin, third segment with setaceous brush ( Fig. 9F View FIGURE 9 ). Hypopharynx: lingua bell-like, with tuft of setae on apex; superlinguae extended laterally, with round and curved apex, and row of hair-like setae along the outer margin from base to apex ( Fig. 9D View FIGURE 9 ). Labium: glossae long ellipse, outer margin slightly expanded, inner margin with tuft of long setae; paraglossae expanded into distinct lobes; labial palp 2-segmented, outer margin of second segment with setae brush, dorsal surface with scattered golden setae ( Fig. 9E View FIGURE 9 ).

Thorax: pronotum extended laterally, subequal to head width ( Fig. 8 View FIGURE 8 A–B). Supracoxal spurs small and round. Femora of all legs pale and dorsally with 3 brown markings, middle dot V shaped and apical one dark brown, outer margin with long bristles, scattered spatulate setae on dorsal surface and blunt projection on apex ( Fig. 10 View FIGURE 10 A–C, 10G). Foretibiae 0.91x length of forefemora, outer margin and dorsal surface with rows of sparse setae, inner margin with row of spine-like setae; foretarsi yellowish, 0.38x length of tibiae, outer margin with tiny spine-like setae ( Fig. 10A, 10D View FIGURE 10 ); tibiae of midlegs similar to foretibiae except 0.95X length of femora, outer margin with dense setae; tarsi similar to foretarsi except 0.28x length of tibiae ( Fig. 10B View FIGURE 10 ); hindlegs similar to midlegs in structure except tibiae 0.8x of femora in length, tarsi 0.3x length of tibiae and with rows of setae on outer and inner margins ( Fig. 10C View FIGURE 10 ). Claws of all legs with a large denticle and 5 subapical denticles, among those the first two smaller ( Fig. 10D View FIGURE 10 ).

Abdomen: terga I–IX each with median dorsal ridge only and row of small pointed spines on posterior margin, an additional brown stripe besides those spines; terga V–VI each light brown with pair of pale dots on median and pair of brown stripes laterally (terga I–IX each with pair of brown stripes but only terga V–VI visible obviously); tergum VIII pale with brown marking on posterior margin, terga IX–X dark brown, with pale dots ( Fig. 8A, 8D View FIGURE 8 ); posterolateral angles of terga I–VII extended slightly into small round projections; posterior margin of sternum IX and tergum X slightly concave ( Fig. 8C, 8E View FIGURE 8 ). Gill I banana-shaped, outer margin extended, lamella longer than fibrilliform portion ( Fig. 10E View FIGURE 10 ); gills II–IV divided into 2 portions, the outer portion banana-shaped while inner portion round lobe-like ( Fig. 10F View FIGURE 10 ); gills V–VI lamellae broad oval, each with round projection towards the posterior end ( Fig. 10H View FIGURE 10 ); gill VII with lamella only, leaf-like, with blunt projection and slightly asymmetrical ( Fig. 10I View FIGURE 10 ). Caudal filaments pale with whorls of spines on articulations ( Fig. 8E View FIGURE 8 ).

Male imago (in alcohol, Figs 12–13 View FIGURE 12 View FIGURE 13 ): body length 8.0–9.0 mm, forewing 8.0–9.0 mm, hindwing 2.8–3.0 mm, cerci 17.0–20.0 mm. Body pale with brown stripes ( Fig. 12A View FIGURE 12 ); anterior margin of head not produced, compound eyes contiguous, upper portion grey and lower portion black ( Fig. 12 View FIGURE 12 C–D). Thoracic mesonotum with apparent transverse suture, lateral parapsidal sutures slightly straight, joining posterior transverse suture ( Fig. 12C View FIGURE 12 ). Prosternum relatively flat; mesothoracic furcasternum parallel ( Fig. 12D View FIGURE 12 ). Forewing hyaline, crossveins pigmented dark brown between C, Sc, R 1 and Rs, but crossveins reduced in number in the Sc and R 1 fields; Rs and MP forked sub- equidistant from base of wing to margin, MA forked over 1/2 of distance from base of wing to margin ( Fig. 13A View FIGURE 13 ). Hindwing transparent, with a projection near basal costal vein ( Fig. 13B View FIGURE 13 ). Femora of forelegs brown, with two dark dots on middle and apex, tibiae pale but basal part black, tarsi pale; midlegs and hindlegs similar to forelegs ( Fig. 12A View FIGURE 12 ). Terga I–IX of abdomen pale, each with dark brown stripe on posterior margin, terga V–VIII with pair of oblique brown stripes laterally, those on terga V–VI hardly visible ( Fig. 12E View FIGURE 12 ).

Genitalia: styliger plate convex with 2 small lateral projections ( Fig. 13 View FIGURE 13 C–D). Forceps segment 2 straight, segments 3–4 less than half length of segment 2, segment 4 long oval, shorter than segment 3. Penes lobes fused with V shaped apical incision and well-developed apical sclerite, inner surface and stem base of penes with scleroses; with median spine-like titillators subapically and mesally ( Fig. 13 View FIGURE 13 C–D). Cerci pale with brown articulations ( Fig. 12A View FIGURE 12 ).

Female imago (in alcohol, Figs 12B, 12F View FIGURE 12 , 13E View FIGURE 13 ): body length 7.0–9.0 mm, caudal filaments 13.0–15.0 mm, forewing 8.0–9.0 mm, hindwing 2.7–3.0 mm. Similar to male imago except as follows: terga I–IX each with pair of lateral brown stripes ( Fig. 12F View FIGURE 12 ); pigmented crossveins of forewings present between Sc and R 1. Posterior margin of subgenital plate produced to 1/2 of sternum VIII; subanal plate with convex posterior margin ( Fig. 13E View FIGURE 13 ). Articulations of cerci brown ( Fig. 12B View FIGURE 12 ).

Egg ( Fig. 14 View FIGURE 14 ): Egg ovoid, chorion decorated with irregular plate-like knob-terminated coiled threads (KCTs) and small tubercle-like projections ( Fig. 14 View FIGURE 14 A–B).

Etymology: The Latin specific name lamellosus refers to blade or lamina. It indicates the nymphs of this species possess gills II–IV split into 2 portions.

Diagnosis. This species can be distinguished from others in the genus Notacanthurus by the following combination of characters. In nymph: 1) dorsal lamellae of gills II–IV divided into 2 portions; 2) abdominal terga I–IX with small dorsal ridges; 3) claws with 5 subapical denticles; 4) femora of all legs with 3 brown markings on dorsal surface. In imagoes: 1) styliger plate with median convex posterior margin and 2 small lateral projections; penis lobes slightly expanded laterally, with sclerites apically and ventrally; 2) pigmented crossveins between Sc and R 1 of male imago reduce in number; 3) abdominal terga V–VIII with oblique stripes; 4) posterior margin of subgenital plate of female reaching half of sternum VIII.

The nymph of N. lamellosus sp. n. is similar to N. edentatus Braasch (1986) by having a median dorsal ridge only, without posterior spines. However, compared to N. edentatus , the nymph of N. lamellosus sp. n. has smaller body size (7.0 mm), head width 1.6x of length, row of long setae up to the concave margin of the superlinguae. In contrast, the nymph of N. edentatus has larger body size (11.0– 12.3 mm), head width 1.4x of length, superlinguae with row of long setae along the outer margin from base to subapical portion.

The male imago of N. lamellosus sp. n. can easily distinguished form other congeners by unspecialized anterior

margin of head, color pattern of abdomen, shape of genitalia and reduced crossveins in the field of Sc and R 1.

Additionally, the eggs of the two new species are different to those of N. baei . The eggs of the latter species have

microgranules and crenulated granules while both N. maculatus sp. n. and N. lamellosus sp. n. have tubercle-like

projections only. The plate-like KCTs of N. lamellosus sp. n. is unique within the genus.

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