Paratanytarsus geminilacus, 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 : 37-38

Paratanytarsus geminilacus sp. nov.

urn:lsid:zoobank.org:act:B25673BE-C3FB-4161-A7E7-922DA33CC161

Fig. 8A–D

Type materials. Holotype male; USA, Alaska, Juneau, Twin Lakes ; 16.vii.2012; leg. Patrick Hudson; dep. UAM . Paratypes 3 males; same as holotype. Paratype 1 male; same as holotype except 6.vi.1998.

Etymology. The new species is named after its type locality. The word “ geminilacus ” is Latin, meaning Twin Lakes.

Diagnosis. The adult male of P. geminilacus can be distinguished from other species of Paratanytarsus by the combination of the following characteristics: AR 1.3–1.4. Frontal tubercle prominent 16–22, 18 μm long. Tergite IX tubercles or humps prominent. Sternapodeme very thick. Anal point apically rounded. Anal crests semicircular, attached only basally, forming a floret-shape structure. Superior volsella circular; digitus robust and extending beyond inner margin of superior volsella, with sharp apex. Median volsella with numerous spoon-shaped setae, more prominent anteriorly, basally with simple setae. HR 0.8–0.9; HV 2.1–2.6, 2.4.

Male (n = 4)

Total length 3.1–3.3, 3.2 mm; wing 2.1–2.5, 2.3 mm long and 0.46–0.57, 0.53 mm wide.

Coloration of mounted specimen. Head, thorax, abdomen, and legs brown. Halteres and wings greyish-brown.

Head ( Fig. 8A ). Eyes bare, with dorsomedial extension. Tentorium 142–165, 149 μm long. Coronal setae 4. Temporal setae around 11–12 in single row. Antenna with 13 flagellomeres; last flagellomere with around 10 sensilla chaetica with 2 being prominent; plume well-developed; AR 1.3–1.4 ( Fig. 8B ). Frontal tubercle prominent 16–22, 18 μm long. Clypeus square, bearing 16–24 setae, clypeus 79–98, 92 μm long and 71–99, 85 μm wide (maximum), clypeus setae 63–102, 89 μm long. Palpal segments lengths (in μm): 74–88, 78; 47–53, 47; 120–150, 133; 198–231, 215.

Thorax. Scutal tubercle present, 6–8 μm high, 30–35, 33 μm wide. Acrostichals 12–14 biserial, dorsocentrals 8–12, 10 uniserial, prealars 1, scutellars 6. Humeral pit very small circular.

Wing ( Fig. 8C ). Membrane setose, more prominent in the distal half. Brachiolum with 2 setae, R with 25–30, 28 setae, R 1 with 26–31, 29 setae, R 4+5 with 47 setae. VR 0.52–0.54.

Legs. Foretibia with straight spur 12 μm long. Mid and hind tibiae with 2 separated combs each with 13–15 branches. Mid tibia spur 13–19, 15 μm long, hind tibia spur 14–16, 15 μm long. Lengths and proportions of legs as in Table 9.

Hypopygium ( Fig. 8D ). Anal tergal bands V-shaped, ending at prominent quadrate tubercles or humps each bearing 2–3 strong lateral setae. Sternapodeme very thick, phallapodeme 56–58 μm long. Anal point apically rounded. Anal crests semicircular, attached only basally, forming a floret-shape structure. Gonocoxite 110–118, 115 μm long, gonostylus 119–153, 134 μm long; gonostylus evenly curved, crescent shape. Superior volsella circular, 36–41 μm long and 33–42 μm wide, dorsal surface with 3–5 setae, inner margin with 2–3 setae, without microtrichia; digitus 32–42, 37 μm long, robust, extending beyond inner margin of superior volsella, with sharp apex. Median volsella with numerous spoon-shaped setae, more prominent anteriorly, basally with simple setae; stem 39–45, 39 μm long, nearly straight. Inferior volsella 66–86, 77 μm long, apically swollen, bearing around 10 strong setae. HR 0.8–0.9; HV 2.1–2.6, 2.4.

Remarks

A combination of small scutal tubercle, apically rounded anal point, spoon-shaped setae of median volsella, and robust digitus places the P. geminilacus in kaszabi group along with Paratanytarsus abiskoensis Reiss & Säwedal, 1981 , Paratanytarsus kaszabi Reiss, 1971 , Paratanytarsus koreanus Reiss & Säwedal, 1981 , and Paratanytarsus mediterraneus Reiss & Säwedal, 1981 . A combination of shorter median volsella, sharper digitus, more circular superior volsella and apically swollen inferior volsella separates P. geminilacus from P. abiskoensis and P. kaszabi . Higher antennal ratio, the shape of the anal point and its crests, along with the shape of the sternapodeme and size of median volsella setae, separates P. geminilacus from those of P. koreanus and P. mediterraneus . Additionally, tergite IX of P. geminilacus has more prominent tubercles or humps where anal bands end, separating it from the known species in this group.

Figures

FIGURE 8. Paratanytarsus geminilacus sp. nov. adult male (A–D). A. Head. B. antenna, C. wing, D. hypopygium, dorsal and ventral. Scale bars are 50 µm.