Procladius (Holotanypus) barbatulus Sublette, 1964

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 : 30-32

Procladius (Holotanypus) barbatulus Sublette

Material examined. USA: California, 1.7 miles east of Benton Hot Springs, 21-VIII-67, col. Jon Martin.

Adult male (n = 1). Total length approximately 3.7 mm.

Head. AR 1.80. Temporal setae 23-24. Clypeus with 15 setae. Palpomere lengths (µm): 50, 70, 105, 148, 238.

Thorax. Antepronotals 8-9. Dorsocentrals 19. Prealars 16-17. Acrostichals 40. Prescutellars 7. Supraalar 1. Scutellars 22.

Wing. VR 1.46. Brachiolum with 3 setae; R with 14-17 setae, R 1 with 13 setae, R 4+5 with 19-23 setae. Squama with 32-36 setae. Extended part of costa 100 µm long. Wing length 2.1 mm. Total length/wing length 1.76. Dark spot over r-m extending to part of m-cu.

Legs. Spur of front tibia 55 µm. Spurs of middle tibia 38-40 µm and 48-50 µm. Spurs of hind tibia 38 µm and 73 µm. Width at apex of front tibia 58- 60 µm; middle tibia 53-58 µm; hind tibia 70-73 µm. Comb with 11 setae; shortest seta 30 µm long, longest seta 58-63 µm long. One pseudospur present on ta 1 of all legs and one pseudospur on ta 2 of mid and hind legs. Pseudospurs 30-43 µm long. Additional measurements and proportions are in Table 1 .

Hypopygium. Tergite IX with 21 setae. Transverse sternapodeme 195 µm. Phallapodeme 75 µm. Strut ratio 2.84. Gonocoxite 213 µm long, gonostylus 100 µm long, gonostylus ratio 10. HR 2.13; HV 3.70.

Pupa (n = 1). Total length 4.80 mm.

Cephalothorax. Faint brown, mostly translucent. Thoracic horn ( Fig. 1 ) brown; 380 µm long; with triangular teeth, sometimes rounded apically; no reticulation; plastron plate length 75 µm; horn width, plastron plate width and apical constriction of horn chamber not measurable.

Abdomen. Color pattern 1, entirely translucent. Shagreen ( Fig. 2 ) of T IV medially with small points (1-2 µm) often arranged in short rows and similar in size to medial points on T VIII. LS taeniae of VII at 0.45, 0.53, 0.80, 0.93 segment length. LS taeniae of VIII at 0.30, 0.48, 0.63, 0.80, 0.93 segment length. Anal lobe length 500 µm; 35-36 spines on outer margin, often bifid or trifid; largest spines 25-27 µm long with spine size similar for much of the margin; smaller spines apically with inner 2-3 spines on a protuberance ( Fig. 3 ).

Larva (n = 1)

Head. Head capsule length about 650 µm. Antenna in Fig. 4 . Antennal segment 1-4 lengths (µm): 155-157, 20, 5-6, 2. AR 3.95-4.05. Basal antennal segment 30-33 µm wide; 4.8-5.2 times as long as wide; ring organ 0.73 from base; blade 27.5 µm long. Mandible 135-140 µm long. Maxilla features not distinguishable. Dorsomental teeth in Fig. 4 and ligula in Fig. 5 .

Abdomen. Features not distinguishable.

Remarks. As only the second specimen reported, after the holotype, adult and larval traits were included for comparison to Sublette (1964) and Roback (1971). In Roback (1980) this specimen keys to couplet 18 for P. freemani , and in Saether (2010) to couplet 9 and P. freemani . With only a single specimen, it is not certain that any feature can be used to distinguish P. barbatulus from P. freemani in the pupal stage. Features span all three of Roback’s variants (with var. 2 the best fit) and are also similar to specimens described by Saether. The larva keys to couplet 14 in Roback and appears indistinguishable from other species in this couplet.

Habitat may be the same as most P. freemani , which is typically lakes, and the type specimen is from Hume Lake , a reservoir in Sequoia National Forest. Based on slide information, the Benton Hot Springs specimen presented here may be from spring-fed desert streams or related pools .

Known range for P. barbatulus is California, USA, in Fresno and Mono Counties.

Figures

Figures 1-3. 1, Procladius barbatulus thoracic horn (Scale = 0.1 mm); 2, tergite IV medial shagreen (Scale = 0.025 mm); 3, tergite VIII and anal lobe (Scale = 0.1 mm).

Figures 4-5. 4, Procladius barbatulus antenna, mandible, and dorsomental teeth; 5, ligula (Scale = 0.025 mm).

Tables

Table 1. Procladius barbatulus, male. Lengths (in µm) and proportions of legs.

	fe	ti	ta 1	ta 2	ta 3	ta 4	ta 5
p 1	770, 780	940, 970	690	340	250	170	120
p 2	850	910, 940	580, 590	300	210, 230	140, 150	100
p 3	770, 780	1050	700, 740	350, 370	250, 260	160, 170	120,130
	LR	BV	SV	BR
p 1	0.61	2.73	2.42	2.92
p 2	0.70, 0.71	3.08, 3.12	2.92, 2.95	2.69
p 3	0.65, 0.67	2.86, 2.88	2.51, 2.56	2.71, 2.85