Chaetocladius (Chaetocladius) mendenhallensis, Namayandeh & Hudson & Bogan & Hudson, 2024

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 : 25-27

Chaetocladius (Chaetocladius) mendenhallensis sp. nov.

urn:lsid:zoobank.org:act:91F414D8-40FE-4B3B-A430-20433063A47C

Fig. 3B, E, H, K, N

Type materials. Holotype male; USA, Alaska, Juneau, Mendenhall Lake ; 16.iii.2013; 58.4217, -138.5388; leg. K. Frangos & J. Hudson; dep. UAM.

Etymology. The new species is named after its habitat, Mendenhall Lake, where it was collected. The suffix “ ensis ” is Latin meaning belongs to.

Diagnosis. The adult male of the C. mendenhallensis can be distinguished from other species of Chaetocladius by the combination of the following characteristics: large species; temporal setae around 13; last antennal flagellomere with 12 sensilla chaetica; AR 1.8; third palpomere with 12 sensilla clavata clustered together; dorsocentrals 14; squama of the wing with 14 setae, costa moderately extended beyond R 4+5, and wing microtrichia visible at 10 x; anal point triangular and pointed apically; virga consist of two spines; sternapodeme arched; inferior volsella receded and rounded, covered in simple setae, close to posterior 1/3 rd of the gonocoxite; gonostylus short, expanded medially to apex, triangular crista dorsalis slightly rising at mid-section.

Male (n = 1)

Total length 5.2 mm; wing 2.3 mm long and 0.9 mm wide.

Coloration of mounted specimen. Head and thorax light brown. Halteres and wings greyish brown. Legs and abdomen yellow.

Head. Eyes bare, with short wedge-shaped dorsomedial extension. Tentorium 221 μm long, narrow and pointed apically, tentorial pit close to apex ( Fig. 3B ). Coronal setae 4. Temporal setae around 13 including 2 outer and 8 uniserial orbitals and 3 postoculars. Antenna with 13 flagellomeres, plume well-developed, last segment with around 12 sensilla chaetica, each of segments 2 and 3 with 2 sensilla chaetica, AR 1.8. Clypeus rectangular, bearing 8 setae, clypeus 102 μm long and 162 μm wide (maximum), clypeus setae 112–132, 122 μm long. Palpal segments lengths (in μm): 96, 64, 197, 170, 325; third palpomere with 12 sensilla clavata clustered together.

Thorax. Acrostichals 14 starting close to antepronotum, dorsocentrals 14 in single row, prealars 4, scutellars 6, antepronotal lobes with 5 setae laterally. Humeral pit developed, small with several pits.

Wing ( Fig. 3E ). Anal lobe squared. Squama with 14 setae. Brachiolum with 1 seta, R with 14 setae, R 1 with 2 setae, R 4+5 with no setae, other veins bare. Costa extension 76 μm long. Microtrichia visible at 10 ×.

Legs. Fore tibial spur 79 μm long, mid tibial spurs 42, 37 μm long, hind tibial spurs 89, 34 μm long, hind leg comb with around 24 spines. Hind tibia spur as in Fig. 3H . Pseudospurs present on mid and hind tarsal segments 1–3. Pulvilli developed but small. Mid and hind trochanter without keel. Lengths and proportions of legs as in Table 3.

Hypopygium ( Fig. 3K ). Tergite IX with around 14 simple setae close to the anal point. Anal point triangular, pointed at the apex ( Fig. 3K & N ), 71 μm long. Virga consists of two long spines ( Fig. 3K ), 95 μm long; apparent hyaline lamellas adjacent to virga. Sternapodeme arched, 146 μm long. Phallapodeme 125 μm long, with narrow and wavy sclerotization extending to the aedeagal region. Inferior volsella receded and rounded, covered in simple setae, close to posterior 1/3 rd of the gonocoxite. Gonocoxite 325 μm long. Gonostylus short, expanded medially to apex, triangular crista dorsalis slightly rising at mid-section, gonostylus 93 μm long, large spine close to megaseta; megaseta 16 μm long. HR 3.5, HV 5.6.

Figures

FIGURE 3. Chaetocladius (s.s.) frangosi sp. nov. (A, D, G, J, M); Chaetocladius (Chaetocladius) mendenhallensis sp. nov. (B, E, H, K, N); Chaetocladius (Chaetocladius) tonitrus sp. nov. (C, F, I, L, O), adult males. A–C. tentorium, D–F. wing, G–I. hind tibia spur, J–L. hypopygium. Scale bars are 50 µm.