Procladius (Holotanypus) clavus Roback

Egan, Alexander T. & Langton, Peter H., 2018, DESCRIPTIONS OF FOUR NEARCTIC PROCLADIUS SKUSE PUPAL EXUVIAE Abstract, CHIRONOMUS Journal of Chironomidae Research 31, pp. 30-36 : 32-33

Procladius (Holotanypus) clavus Roback

Material examined. Canada: British Colombia, Box 4 Lk., Riske Cr. B.C., 1-VI-1970, col. R. Cannings .

Adult males (n = 3).

Hypopygium. Tergite IX with 44-62, 53 setae (n = 3). Transverse sternapodeme 280-307, 296 µm long (n = 3). Phallapodeme 100-113, 106 µm long (n = 6). Strut ratio 2.10-2.50, 2.26 (n = 6). Gonocoxite 220-250, 239 µm long (n = 6). Gonostylus 118-138, 130 µm long (n = 6). No lobes present for measuring the gonostylus ratio. HR 1.72-1.92, 1.84 (n = 6).

Pupa (n = 3). Total length 6.37 mm, range 6.1-6.5 mm

Cephalothorax. Faint brown, mostly translucent. Thoracic horn ( Fig. 6 ) 450-520, 483 µm long (n = 4); 140-150, 145 µm wide (n = 2); with teeth; no reticulation; plastron plate 70-98, 84 µm long (n = 4); 106-120, 113 µm wide (n = 2); apical constriction of horn chamber 70-85, 78 µm wide (n = 2); length/width of horn 3.27-3.85, 3.56 (n = 2); width of plastron plate/width of horn 0.79-0.80, 0.80 (n = 2); width of plastron plate/width of constriction 1.41-1.51, 1.46 (n = 2).

Abdomen. Color pattern 1, entirely translucent. Shagreen ( Fig. 7 ) of T IV medially with small points (2 µm) arranged in loosely connected, elongate rows and smaller than median points of T VIII (3-5 µm). LS taeniae of VII at 0.50, 0.69, 0.86, 0.96 (n = 3) segment length. LS taeniae of VIII at 0.30, 0.45, 0.61, 0.77, 0.93 (n = 3) segment length. Anal lobe length 700-820, 787 µm; 43-54, 49 (n = 5) spines on outer margin; largest spines (22-30 µm) posterolateral, usually with gaps narrower than spine base; basal spines broadly triangular; apical spines 10-15 µm, directed posteriorly, and usually on a small protuberance or clustered together with a shared base ( Fig. 8 ).

Remarks. All specimens were pharate, making adult features difficult to observe so only hypopygium measurements were included. In Roback (1980) these specimens key to couplet 13, in Saether (2010) to couplet 6, and are similar to P. culiciformis . Saether’s measurements of P. culiciformis were generally similar to Sublette’s Riske Creek specimens, but it is possible that P. clavus can be distinguished by the wider apical constriction of the horn chamber, which also leads to a smaller ratio for width of plastron plate/width of constriction. Saether describes P. culiciformis anal lobe inner margins as having small spines, which are not present in clavus specimens. Finally, figures of the thoracic horn in both Saether and Roback show the P. culiciformis apical constriction as having a rather long neck, while in clavus the neck is short enough that it was hard to determine the width, and therefore the horn may resemble P. paragretis or P. ruris .

Known range is British Colombia and Nunavut, Canada.

Figures

Figures 6-8. 6, Procladius clavus thoracic horn (Scale = 0.1 mm); 7, tergite IV median shagreen (Scale = 0.025 mm); 8, segment VIII and anal lobe (Scale = 0.1 mm).