Amphialycus walteri, Uusitalo, 2025

Amphialycus walteri sp. nov.

( Figs. 14A–E, 15A–E)

Amphialycus cf. leucogaster View in CoL .— Walter & Latonas 2012: 62; Walter & Lumley 2021: 74.

Description. Dorsum (n= 4 females, Fig. 14A, B). Length 400 µm; ciliate setae with long central points (12–14 µm), especially on caudal segments (16–20 µm). On prodorsum: naso flap-like, longitudinally striated with roundish tip; pilose setae vi set well back, sce and exp plumose on hard integument, exp smallest and anterior to eyes, setae in columnar, bushy; two pairs of filamentous sensilla ve and sci ciliated along entire length; both pairs of lateral eyes finely striated.

Venter ( Figs. 14D, E, 15E). Setae shorter and less ciliated than dorsal setae; genital setae of various lengths, mostly elongated closer to mesial margin, 19–21 per valve; anal setae 4 per valve.

Gnathosoma ( Fig. 14C). One pair of smooth, abaxial cheliceral setae; rutella mitten-shaped, widening to a round hyaline membrane with two lobes apically; three pairs of well-developed adoral setae; four microtrichous eupathidia on palps close to each other but clearly apart.

Legs ( Fig. 15A–E). Pedal setae elongated; solenidial formula for tarsi, tibiae, genua and femora on legs I-II-III- IV, respectively: 2-2-0-0, 3-2-2-0, 3-2-2-1, 2-0-0-1+0, ceratiform solenidia on femora I longer than other solenidia; coxae III and IV with 3 setae, Remarks.

Type material. Holotype female and 3 paratype females as Amphialycus cf. leucogaster from aspen ( Populus tremuloides ) litter under snow, Moose Pasture Research Site , 8 km W Chipman, Lamont Co., 53°39’37’’N 112°45’21’’W, Alberta, Canada, 17 February 2008, David E. Walter: 4 female cotypes on one slide (8) TMS: M00016839 View Materials at the Royal Alberta Museum, Edmonton, Alberta, Canada. GoogleMaps

Differential diagnosis. This species can be differentiated from Amphialycus holarcticus by having a naso with a roundish tip, one cheliceral seta, fewer genital, anal and coxal setae (Uusitalo 2020: fig. 6), and two solenidia on tarsus II; and from Amphialycus leucogaster ( Grandjean, 1937) by having dorsal and prodorsal setae with longer shafts; crista with longitudinally (not transversely) orientated lamellae ( Uusitalo 2010: figs. 71–73), three pairs of well-developed adoral setae (instead of one), and two ceratiform solenidia on tibia I (instead of one).

Remarks. Poor visibility of the distal parts of tarsi I and II prevented reliable observation of the minute famulus I and II. Amphialycus walteri was not known when preparing the phylogenetic tree ( Uusitalo 2010: fig. 1).

Etymology. The specific name (a patronymic genitive) is given in honour of Dr. David Evans Walter, the collector and first recorder of this genus in North America.