Phthinia cascadica Fitzgerald & Kerr

Fitzgerald, Scott J. & Kerr, Peter H., 2014, Revision of Nearctic Phthinia Winnertz (Diptera: Mycetophilidae), Zootaxa 3856 (3), pp. 301-325 : 305-308

Phthinia cascadica Fitzgerald & Kerr n. sp.

Figs. 1–8

Type material. Holotype: ♂ ( Fig. 1 ) [specimen #12K577; CSCA], missing right front leg, otherwise complete, point-mounted, USA: CA: Humboldt Co., Prairie Creek SP, Cal Barrel Rd., appx. 41.3830ºN, - 123.9985ºW, 275masl, 2.vi–25.vii.2009, P. Kerr & O. Lonsdale, 6m MT, CSCA 09L521. Paratypes: ♂ [09C884; CSCA], USA, Ore., Josephine Co., small trib. of Josephine Ck, above USFS Rd 4201 Xing, 42°14.168'N 123°42.055'W, MT 475m, 22 May–1 Jun 2009, GW Courtney, CSCA 09L406; 8 ♂♂, ♀ [12K576–12K582, 12K584, 12K892; CSCA], USA: CA: Humboldt Co., Prairie Creek SP, Cal Barrel Rd., appx. 41.3830ºN, - 123.9985ºW, 275masl, 2.vi–25.vii.2009 P. Kerr & O. Lonsdale, 6m MT, CSCA 09L521; ♂ in alcohol [10F479; CASC], USA: CA: Del Norte Co, Six Rivers NF, For Route 16N02, nr. Bear Basin Outlk, 41.8016ºN, 123.7369ºW, 1500masl, 3.vi–4.vii.2009 P. H. Kerr & O. Lonsdale, 6m MT, CSCA 09L526; ♂ [13M447; CSCA] USA: CA: Marin: Pt. Reyes N Seashore; Mt Vision Rd, 1.8 mi E SF Drake Blvd, 6m MT, 38.1013ºN, - 122.8878ºW, P. H. Kerr, C. Borkent 1.v–4.vii.2012 CSCA 12L079; ♂ [ ISUI], Linn Co., OR, McDowell Creek Falls, 18 Oct. 2009, S. Fitzgerald; ♂ [ OSAC #0000770505], USA: OR: Benton Co., Corvallis, SW Allen St., sweeping over log pile, 44.5472ºN, - 123.2698ºW, 16 Nov. 2012, S. Fitzgerald; 2♀♀ [1 OSAC #0000770504, 1 USNM], USA: OR: Benton Co., Alsea Falls area, Fall Creek jct. trail 6, 44.3199ºN - 123.4899ºW, 17 Oct. 2012, S. Fitzgerald; ♀ [ SFC], Benton Co., OR, 1460 SW Allen St., Corvallis, 23 Nov.– 6 Dec. 2009, S. Fitzgerald; ♂ [ SFC], USA: OR: Benton Co., Mary’s Peak, upper Parker Creek nr. campground, 44.5087ºN, - 123.5583ºW, 1 June 2013, S. Fitzgerald; ♂, [ SFC], Multnomah Co., OR, off E. Historic Columbia R. Hwy 1 mi. E. jct. 84 (exit 28), ca. 45.5672 -1221578, 18 Sept.–23 Oct. 2013, S.J. Fitzgerald, Malaise trap; ♀ [ SFC], USA: OR Benton Co., OR, 1460 SW Allen St., Corvallis, 44.5509ºN, - 123.2700ºW, pupa suspended by threads on white encrusting fungus on underside of rotten log under canopy of maple, elm, and cherry, 31 Oct. 2013, emerged 3 Nov. 2013, S. Fitzgerald; ♀ [ SFC], USA: OR Benton Co., OR, 1460 SW Allen St., Corvallis, 44.5509ºN, - 123.2700ºW, 8 Nov. 2013, porch light, S. Fitzgerald; ♂ [ CNCI], CANADA: BC: Capilano 300m, N. Vancouver, 17 X 1972, J.R. Vockeroth. Additional material: 4 ♂♂ [ CASC], CANADA: British Columbia: Upper Carmanah Valley, 21 VI-7 VII 1991, N. Winchester, CC.MT5; 4 ♂♂ [ CASC], CANADA: British Columbia: Upper Carmanah Valley, 21 VI-7 VII 1991, N. Winchester, TZ.MT5.

Etymology. This species is named after the bioregion (and proposed country) Cascadia, known for its rich natural heritage and environmental sensibilities.

Diagnosis and comments. Phthinia cascadica can be distinguished from all other Phthinia by the stronglydeveloped, digitate, posteriorly-directed, posterodorsal lobes of the gonocoxites which are unique within the genus. The only other taxon with distinctly dorsal lobes on the gonocoxites is P. parafurcata Oliveira & Amorim (described from Chile), but the dorsal lobes in this species are mesally-, rather than posteriorly-directed. In California and Oregon, where only P. neptunei n. sp. and P. cascadica n. sp. have been recorded, females of the two species can be distinguished by the different distribution of macrotrichia on the wing, the relative divergence of A1 from the petiole of the cubital fork, and the presence/absence of posterior setae on the hind tibia (see couplet 1 in key). Based on a single specimen collected in 2012 from Pt. Reyes National Seashore (Marin Co., California), we believe there may be another species of Phthinia that is very closely related to P. c a s c ad i c a. However more specimens are needed to confirm this and document its morphology adequately for proper diagnosis and taxonomic publication.

Description. Male. Body length: 6.2–8.4, 7.4 [7.6] mm (n=8). Head. First flagellomere longer, approx. subequal the length of flagellomere 2. Thorax ( Fig. 2 ). Laterotergite with several setae. Scutellum with 4 stronger bristles (although sometimes only 2–3 apparent and sometimes all setae are shorn off). Legs. First tarsomere of foreleg approx. 2.5 times length of foretibia, first tarsomere of midleg approx. 1.7 times as long as midtibia, and first tarsomere of hind leg approx. 0.7 times as long as hind tibia. Apex of hind tibia with apex ventrally produced into a keel-like point bearing the outer tibial spur apically. Hind tibia with 2–6 minute anterior setae, 17–27 minute dorsal setae, and 8–10 minute posterior setae (N=2); midtibia also with a small number of minute anterior and dorsal setae. Wings (as Fig. 3 ). 4.2–5.5, 5.0 [5.3] mm (n=8). Membrane with macrotrichia; microtrichia also present between more widely spaced macrotrichia. C extending about 1/3 of the distance between R5 and M1; Rs about 1/4 length r-m; r-m subequal to slightly longer than stem of M; medial fork complete; M1 distinct basally. A1 diverging only slightly from stem of CuA. ( Fig. 3 ). Abdomen. Terminalia ( Figs. 4–7 ). Terminalia beige-brown to light brown, contrasting with darker color of abdomen. Cerci short, lobate, apically rounded with small setae. Hypoproct about as long as wide, much longer than more dorsally situated cerci ( Figs. 4, 6 ); posterior margin with a broad, shallow, v-shaped emargination. In dorsal view ( Fig. 6 ), gonocoxite developed dorsally beyond point of articulation of gonostylus into an apical (posteriorly directed) digitate, apically rounded, setose lobe devoid of strong spine-like setae. Gonostylus with five lobes ( Figs. 5, 7 ); two mesally-directed lobes, one apically-directed lobe, and two spine-like posteriorly-directed lobes (the latter best seen in ventral view, Fig. 7 ); the former three lobes are less sclerotized, more or less apically rounded, and covered with setae over most of surface; apically-directed lobe with strong setae. The two strong, subequal, spine-like, posteriorly-directed lobes are primarily bare and setose only basally ( Figs. 4, 7 ). In ventral view, aedeagal complex protruding ventromedially beyond ventromedian margin of gonocoxites; triangular, apically acute ( Fig. 7 ).

Female. Similar to male; terminalia as Fig. 8 .

Bionomics. Phthinia cascadica n. sp. is recorded from about 38ºN latitude California north to Vancouver British Columbia with all records in the extreme western parts of the these states/provinces (while we did not examine any specimens from Washington, this species undoubtedly occurs there). Specimens have been collected nearly at sea level, up to 1,097 m, in habitats including coniferous woodlands (including coastal redwood forests in northern California), and mixed woods in semi-wild open spaces on the edges of towns. As noted in the introductory bionomics section, this species was reared from a pupa found suspended by threads in a hollow cavity on the underside of a rotten deciduous log, with the overhead canopy being made up of Big Leaf Maple, Elm, and Cherry trees; the lower surface of the rotten log, including the small hollow in which the pupa was suspended, was covered with a white encrusting fungus. Considering the records, it seems likely that the species is at home in coniferous or deciduous woods as long as an appropriate fungal host can be located. Adults have been swept from a log pile (mix of coniferous and deciduous logs), taken in Malaise traps, and attracted to a porch light. The seasonal distribution is late May–July and September–December (the majority of these fall records occurring within October–November).

Figures

FIGURE 1. P. cascadica n. sp., habitus [holotype male, # 12 K 577]. Scale bar = 1 mm.

FIGURE 2. P. cascadica n. sp., head and thorax [paratype male, # 12 K 576]. Scale bar = 0.5 mm. Abbreviations: anepm anepimeron anepst anepisternum aprnt antepronotum a spr anterior spiracle cx coxa hlt halter kepst katepisternum ltg laterotergite mtg mediotergite mtanepst metanepisternum mtepm metepimeron mtkepst metakatepisternum p spr posterior spiracle proepst proepisternum sc scutum

FIGURE 3. P. cascadica n. sp., wing [paratype male, # 12 K 584]. Scale bar = 1 mm.

FIGURES 4 – 7. P. cascadica n. sp., male terminalia [paratype specimen, # 12 K 584]. 4. Lateral view, with epandrium. 5. Posterior view. 6. Dorsal view. 7. Ventral view. Scale bar = 0.1 mm. Abbreviations: aed comp aedeagal complex cerc cercus epand epandrium goncx gonocoxites gonst gonostylus hyprct hypoproct

FIGURE 8. P. cascadica n. sp., terminalia [paratype female, # 12 K 892]. Scale bar = 0.1 mm.