Notacanthella commodema
Creators: name: Auychinda, Chonlakran
name: Sartori, Michel
name: Boonsoong, Boonsatien
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Ephemerellidae
Notacanthella
Notacanthella commodema

description: Notacanthella commodema (Allen, 1971)
Figures 1, 2, 3, 4, 5, 8 B–C
Ephemerella (Acerella) commodema: Allen, 1971: 520, figs 24–27;
Acerella commodema: Allen, 1980: 82;
Notacanthella commodema: Jacobus and McCafferty, 2008: 236.
Redescription. Mature larvae (in alcohol, Fig. 1; living, Figs 8 B–C). Body length 8.25-8.40 mm without cerci; cerci 9.0- 10.6 mm. Body brown with dark brown markings.
Head. Brown, with two pairs of tubercles; large occipital tubercles and small sub-occipital tubercles. Maxillae with maxillary canine length greater than relative width (Fig. 2A), and with lateral serration (Fig. 2B); three-segmented maxillary palp covered with hair-like setae, segment length ratio from base to apex = 3.3:3.4:1 (Fig. 2C). Left mandible with three outer incisors and two inner incisors; mandibular incisors not enlarged, densely covered with irregularly ordered hair-like setae on dorsolateral surface (Fig. 2D). Right mandible with three outer incisors and two inner incisors, tuft of short setae present in concavity close to molar area, and densely covered with irregularly ordered hair-like setae on dorsolateral surface (Fig. 2E). Labium densely covered with hair-like setae; glossae length greater than width; labial palp three-segmented, first and second segments subequal, third segment small (Fig. 2F). Labrum densely covered with setae, anterior margin somewhat concave medially (Fig. 2G). Hypopharynx: sub-lingua rounded with anterolateral hair-like setae, lingua oval with anterolateral, short setae (Fig. 2H).
Thorax. Pronotum without anterolateral projections; lateral margins convex; dorsal surface with seven tubercles: one median, two sub-median, two lateral and two sub-lateral tubercles. Mesonotum with small and rounded anterolateral projection; lateral margins convex; dorsal surface with 7–9 tubercles: two sub-median anterior tubercles, two or four sub-median tubercles at middle, one median posterior tubercle and two sub-median posterior tubercles (Figs 3 A–B, 4A–B). Foreleg: femur brown with median and apical dark brown bands; dorsal margin with chalazae; ventral margin smooth; tibia and tarsi brown; ratio of femur: tibia: tarsus = 2.4: 2.3: 1. Middle leg similar to foreleg; ratio of femur: tibia: tarsus = 2.5: 2.1: 1. Hind leg similar to foreleg and middle leg; ratio of femur: tibia: tarsus = 2.6: 2.8: 1. All claws with one row of 4–6 denticles (Figs 4 C–D).
Abdomen. Abdominal tergites brown, convex; tergite VIII with obvious wing-like lateral projections; paired dorsal tubercles on segment II–X, tubercles short and narrowly separated at base of segment II, longer and progressively more widely separated on segments III–VIII, long and divergent tubercles on segment VIII, shorter and more narrowly separated on segments IX–X; lateral projections of segment IX not extending beyond segment X (Figs 4 E–F). Posterior margin of sternite IX of female either slightly concave (Figs 5A, 5C) or straight (Fig. 5B); sternite IX of male as in Fig. 5D. Gills III–V with bifurcate and multifoliate ventral lamellae, gill VI ventral lamella integral and multifoliate, gill VII ventral lamella multifoliate; dorsal lamella of gills III–IV rounded (Figs 4–H), dorsal lamella of gills V–VII paddle shaped (Figs 4 I–K). Cerci brown with whorls of small, almost rounded, scale-like setae and few long, bifid setae at apex of each segment.
Diagnosis. The larva of Notacanthella commodema can be distinguished from the other Notacanthella species that are known as larvae based on the following characteristics: 1) two pairs of tubercles on head, 2) seven prominent tubercles on the pronotum, 3) 7–9 tubercles on the mesonotum, 4) well-developed, blunt tubercles on tergites III–VIII, those on tergite VIII clearly divergent.
Character variability. We examined several specimens of different instars and some characters may look different between earlier and later instars.
The larva of N. commodema has the highest number of tubercles on mesonotum among the genus Notacanthella. However, posterior sub-median tubercles are more flattened and difficult to count, but these tubercles should be considered (not included in the description of N. commodema; Allen, 1971). In addition, the tubercle morphology can change during larval development. There are four sub-median tubercles at the middle in early instars but two can be fused and form a flattened tubercle in the last larval instar, and the tubercles become proportionately reduced in size as the larva molts (Figs 3B, 4B). Other characters subject to ontogenetic changes in mature larvae are:
- a body light brown and a broader shape (Fig. 1B);
- head with two pairs of flattened tubercles, especially the sub-occipital tubercles;
- abdominal terga having a pair of shorter and smaller tubercles on segments II-IX and the orientation of abdominal tubercles on segment VII–VIII parallel rather than divergent (Fig. 4F);
- chalazae on the dorsal margin of femora which tend to size and number reduction.
This latter observation seems to indicate that the original description by Allen (1971) was based on late instars.
Adult and Egg: Unknown
Distribution. Chiang Mai and Nan Provinces.
Material examined. THAILAND, Chiang Mai province, Mae Na, Klong Mae Sai, 19°19’18.7”N 98°52’50.8”E, altitude 809 m, 20.XI.2018, C. Auychinda leg., 8 larvae: 2 larvae on slides and 6 larvae in ethanol [ZMKU]; Nan province, Bo Kluea, Wa river, 19°16’22.6”N 101°10’48.2”E, altitude 848, 26.XI.2019, C. Auychinda leg., 3 larvae in ethanol [ZMKU], 6 larvae: 1 larva on slide and 5 larvae in ethanol [MZL]; Chiang Mai province, Mae Na, Mae Mae, 19°19’13.0”N 98°53’25.9”E, altitude 728 m, 20.XI.2018, C. Auychinda leg., 2 larvae [MZL], Chiang Mai province, small stream and waterfalls, Doi Sutep west of Chiang Mai, altitude 1450 m, 8.IX.1964, WL & JG Peters leg., 8 larvae (paratopotypes) [PERC].
description: Published as part of Auychinda, Chonlakran, Sartori, Michel & Boonsoong, Boonsatien, 2020, Review of Notacanthella Jacobus & McCafferty, 2008 (Ephemeroptera: Ephemerellidae) in Thailand, with the redescription of Notacanthella commodema (Allen, 1971), pp. 414-424 in Zootaxa 4731 (3) on pages 415-417, DOI: 10.11646/zootaxa.4731.3.9, http://zenodo.org/record/3653658