Krenopelopia cf. narda Roback, 1971

Namayandeh, Armin, Hudson, Patrick L., Bogan, Daniel L. & Hudson, John P., 2024, Chironomidae (Diptera: Insecta) of Alaska, USA, with descriptions of new species and a checklist, Zootaxa 5511 (1), pp. 1-95 : 23-24

Krenopelopia cf. narda Roback, 1971

Fig. 2A–G

Material examined. 1 Larva; USA, Alaska, Bristol Bay, Tributary to Stuyahok River ; 12. VI .2014; 59.798, - 155.83128; leg. D. Bogan; dep. UAM . 1 Puparium; USA, Alaska, Juneau, Turner Lake , first orders stream entering the lake, moss on the bedrock; 5. VIII .2007; 58.30, -133.88; leg. J. Hudson; dep. UAM. 1 Larva; USA, Alaska, Juneau, Little Sheep Creek ; 21. VI .2019; 58.2446, -134.2929; leg. D. Bogan; dep. UAM . 1 Larva; USA, Alaska, Kupreanof Island , tributary to Duncan Canal; 5. VIII .2019; 56.7486, -133.1838; leg. D. Merrigan; dep. UAM . 1 Puparium; USA, Alaska, Revillagigedo Island, Caroll Creek , 7. VII .2019; 55.7427, -131.4082; leg. L. Jones; dep. UAM . 1 Larva; USA, Alaska, Revillagigedo Island, tributary to Whitman Creek , 12. VII .2019; 55.3437, -131.5261; leg. T . Hasbrouck ; dep. UAM . 1 Larva; USA, Alaska, Sitka , tributary to Nakwasina Sound; 25. VI .2019; 57.1684, -135.4019; leg. D. Bogan; dep. UAM .

Description.

Pupa (n = 2)

Cephalothorax. Thoracic horn 407–417, 412 μm long ( Fig. 2A ). Plastron plate 126–134, 130 μm long and 105–131, 118 μm wide, plastron plate L/thoracic horn L 0.31–0.32.

Mature larva (n = 7; unless otherwise stated)

Total length about 4.2–5.8, 5.0 mm.

Coloration of mounted specimens. Head capsule yellowish-golden with occipital region lighter in contrast.

Head ( Figs. 2B–F ). Head 432–498, 465 μm long, 472–496, 482 μm wide, HL/HW = 0.97–1.0, 0.99. The line formed by cephalic S9–S10-VP-SSm is only slightly curved, VP eye-shaped ( Fig. 2B ), DP present, posterior to S5 ( Fig. 2C ). Antenna 5 segmented, decreasing in size sequentially. AR 2.8–3.3, 3.0. Blade 55 μm (n = 2) long. Style 9 μm long (n = 2). Ring organ located at 2/5 th from the base of the 1 st segment ( Fig. 2D ). Maxillary palp threesegmented, length of the segments in µm, 41–50, 44; 10–17, 13; 7–8; width of the basal segment 41–50, 44 µm; distance from the base to ring organ 22–23 μm. Mandible 112 μm long, accessory tooth small above a prominent and protruding mola, apical tooth with slight basal hump, and bent ( Fig. 2E ). Ligula with 1 receding inner tooth and 2 pairs of outer teeth increasing in size outward ( Fig. 2F ), ligula 70–83, 75 μm long, 38–45, 40 μm wide at the tip, and 31–37, 34 μm wide at the base; paraligula 27–36, 32 μm long, bifid with 1 st tooth much longer ( Fig. 2F ). Pseudoradula with moderately coarse granules, distributed irregularly.

Abdomen. Procercus well-sclerotized, 75–103, 89 μm long and 26–43, 36 μm wide, bearing 7 apical setae, each 415–443, 430 μm long; supraanal seta 272–302, 284. Posterior parapods 238–365, 296 μm long, 151–199, 179 μm wide, bearing 12 simple claws of varying size ( Fig. 2G ).

Remarks

The size and ratio of the thoracic horn of mature larvae (i.e., puparium) we collected falls within what Roback (1983) described as possibly Krenopelopia narda .

Figures

FIGURE 2. Krenopelopia cf. narda Roback, 1971 pupa (A), larva (B–G). A. thoracic horn, B. ventral cephalic setae of head capsule, C. dorsal cephalic setae of head capsule, D. antenna, E. mandible, F. ligula, and paraligula, G. claws of posterior parapods. Scale bars are 20 µm.