Bittacomorpha occidentalis Aldrich 1895

Fasbender, Andrew & Courtney, Gregory W., 2017, A revision of Bittacomorphinae with a review of the monophyly of extant subfamilies of Ptychopteridae (Diptera), Zootaxa 4309 (1), pp. 1-69 : 35-37

Bittacomorpha occidentalis Aldrich 1895

Bittacomorpha occidentalis Aldrich, 1895: 201 (original description) Bittacomorpha occidentalis Aldrich, Johnson 1905: 75 (key)

Bittacomorpha occidentalis Aldrich, Alexander 1916: 546 (key)

Bittacomorpha occidentalis Aldrich, Alexander 1927: 9 (catalog) Bittacomorpha occidentalis Aldrich, Peus 1958: 11 (catalog)

Bittacomorpha occidentalis Aldrich, Alexander 1965: 98 (catalog) Bittacomorpha occidentalis Aldrich, Alexander 1967: 171 (illustration)

Diagnosis. Larva ( Figs. 5 b, 6c–d). Genae expanded posteriorly, cranium completely black; postgena with triangular anterolateral lobes. Abdominal segments with linear longitudinal rows of tubercles. Adult ( Figs. 7 b, 10). Prescutum black, shining; apex of parameres spatulate.

Description. Larva. Head with dorsal surface weakly convex, uniform black. Genae triangular in dorsal view, expanded posteriorly; postgena trapezoidal in shape, apex with triangular anterolateral lobes. Antenna with basal segment button-like, apical segment weakly pyriform, terminal sensilla cluster directed apically. Abdominal segments with linear longitudinal rows of tubercles. Adult. Measurements (n=2). Overall length 10.82mm (10.51– 11.16mm), head width 1.53mm (1.41–1.59mm), height 1.47mm (1.37–1.63mm), length 0.87mm (0.86–0.88mm); antenna flagellum length 6mm, flagellomere proportions: 1.00, 0.48, 0.55, 0.55, 0.51, 0.54, 0.54, 0.54, 0.54, 0.48, 0.41, 0.39, 0.37, 0.31, 0.33, 0.33, 0.31, 0.22, 0.18; maxillary palpus length 2.16mm, maxillary palpus segment proportions 0.17, 1.0, 1.05, 0.66, 0.89; thorax length 2.97mm (2.72–3.2mm), height 2.67mm (2.44–3.04mm), wing length 11.4mm (10.42–12.43mm), wing width 2.52mm (2.8– 2.25mm), R3+4+5 stem 0.82mm, R4+5 stem 2.2mm, R4 after fork 2.59mm, R5 after fork 2.5mm, R3+4+5:R4+5-stem:R4 1.00, 2.68, 3.15, r-m 0.36mm, M distal to r-m 4.35mm, Mdistal:R3+4+5 5.3:1.00, R4:Mdistal 0.59, 1.00, CuA2 2.14mm; leg proportions: femur 1.0, 1.08, 1.25, tibia 0.97,1.02, 1.24, tarsomeres, foreleg 0.48, 0.22, 0.14, 0.06, 0.07, midleg 0.49, 0.23, 0.13, 0.06, 0.05, hind leg 0.58, 0.25, 0.15, 0.05, 0.06; abdomen length 15.66mm (17.50– 14.29mm); male tergite proportions 1.00, 2.97, 2.02, 2.29, 1.9, 0.80, 0.26; male genitalia width 1.1mm, height 0.76mm. Face narrow, incised by clypeolabrum nearly to dorsal margin. Clypeus larger than eye, lateral margins somewhat pinched at junction with face, not inflated. Hypopharynx subconical triangular, directed anteroventrally. Labium extending less than 1/2 length beyond clypeus, labella pad wider than labium. Antepronotum with two small lobes dorsally. Scutum and prescutum shining black, prescutum uniform; post sutural scutum with broad white mark medially. Wing with apex of R1 and R3 with macrotrichia, all other veins bare. Posthalter palpiform. Male. Epandrium with lateral margins straight to base of epandrial clasper, obtusely angled medially above epandrial clasper; posterior margin smoothly curved; posteromedial stylus weak, obtuse. Internal fold extending in a straight line medially with strong anterior deflection. Epandrial clasper pad wider than subapical clasper. Subepandrial sclerite divided, bladelike, base directed anteromedial at weak angle. Parameres laterally compressed, posteroventrally directed basally, dorsoposterior right angle midway along length, medially diected spine basally, paired dorsal and ventral triangular spines at 2/3 length, spatulate apex. Gonostylus always with irregular trichoid sensilla at apex. Hypandrium terminal division arrowhead shape, base petiolate, lateral lobes directed anterodorsally, dorsal surfaces heavily sclerotized. Lateral ejaculatory process lateral apex broadly triangular in lateral view, medial apex broadly triangular, not extended; ventral section elongate larger than dorsolateral section, acute triangle with pointed anterior apex, lightly sclerotized laterally, deeply inserted into sperm sac. Aedeagal sclerites separated by width of ejaculatory apodeme at base; ventral apical apodeme rounded, well sclerotized, directed lateral, not fused with subaedeagal sclerite. Subaedeagal sclerite anterolateral apex forming flat plate with straight medial margin; external portion extending to apex dorsal lobe of apical apodeme. Female. Epigynium posterior margin U-shaped; hypoproct broad triangular, with sclerotized conical sclerite located ventrally, anterolateral apex with acute lobe; cerci dorsal margin straight, apex rounded, ventral margin swollen, potbellied anteriorly tapering posteriorly; cercus epigynium ratio 0.50, 1. Genital fork spatulate, posterior margin weakly emarginate. Hypogynium quadrate, lacking lateral lobes, hypogynial valves distinct, square, medial notch square: 2.5x as deep as broad.

Type material examined. Lectotype. UNITED STATES. WASHINGTON. King Co. Seattle, coll. J.M. Aldrich, Cotype No. 52263 [pinned 1 ♂; USNM] . Paralectotype. Same as lectotype. [pinned 1 ♂; USNM].

Other material examined. UNITED STATES. CALIFORNIA. Plumas Co. Lassen Nat. For. Humbug, 19.vi.2007 40.107°N 121.373°W, coll. J.D. Davis, M.J. Petersen [pinned 4 ♂; ISIC] ; Tehama Co. nr. Lassen N.P., 15.vi.1959, coll. G.W. Byers [pinned 1 ♂, 1 ♀; KU]. OREGON . Benton Co. Muddy Swamp near Oak Creek Lab, 8.vi.1985 coll. J.K. Furnish [alcohol 6 larvae; ISIC] ; Sulphur Springs, Baker Creek Trail, 44.6 395°N, 123.3123°W, 21.v.2012 coll. GW Courtney, from seeps along trail near Xing [alcohol 14 2nd instar larvae, 1 4th instar larva; ISIC] ; Mary’s Peak , 3 mi. below summit, 20.iv.1941, coll. Schuh, Gray [pinned 1 ♀; WSU] . Hood River Co. 12 mi. S. of Parkdale , 29.vii.1938, coll. K. Gray, J. Schuh [pinned 1 ♀; WSU] . Lake Co. Fremont Nat. For., Gilbert Spring at NF3360, Hillside Seeps with vegetation, 42.42599°N 120.75531°W, coll. A. Fasbender 11.vi.2012 [alcohol 2 ♂; ISIC] . Lane Co. 2.7 mi. NW Salt Creek Falls , 24.vi.1959, coll. G.W. Byers [pinned 2 ♂; KU] ; Salt Creek , 24.vi.1959, coll. G.W. Byers [pinned 2 ♂, 1 ♀; KU] . Tillamook Co. 2mi W. Sandlake , 1.v.1973, coll. J.D. Lattin [pinned 1 ♂, 1 ♀; ORSU] . Wasco Co. Mt. Hood Nat. For., Warm Springs, 44.9888°N 121.7901°W, 9.vii.2008, coll. J.D. Petersen [pinned 1 ♂; alcohol 1 ♂; ISIC] ; WASHINGTON. Pierce Co. Mt. Rainier, Nat. Park, Kautz Creek , 19.vi.1966, coll. D.W. Smith [pinned 3 ♂; WSU] ; Thurston Co. Olympia, 2.vi.1895, no collector [pinned 3 ♂; 25.v.95 1 ♂; no date 1 ♂; WSU] ; Yakima Co. Yakima, coll. C.V. Piper, no date [pinned 1 ♂; WSU] .

Taxonomic notes. Bittacomorpha occidentalis is often mistaken for Bi. clavipes , although the species distributions are allopatric. There are several morphological characters that distinguish the species: Bi. occidentalis has a shining black scutum without a median white stripe, the clypeus is elongate, and the male genitalia has parameres with a spatulate apex. The larvae are also distinctive, with the head capsule triangular in dorsal view versus the rounded head capsule of Bi. clavipes . Bittacomorpha occidentalis is the largest species of extant Ptychopteridae .

Distribution. Fig. 18 b.

Figures

FIGURE 5. Larval habitus. a. Bittacomorpha clavipes Fabricius, lateral view (inset = dorsal view of head); b. Bi. occidentalis Aldrich, lateral view; Bittacomorphella fenderiana Alexander, dorsal view. Scale bars 1 mm (a, b), 2 mm (c).

FIGURE 7. Bittacomorphine male wings. a. Bittacomorpha clavipes; b. Bi. occidentalis; c. Bittacomorphella pacifica Alexander; d. Bl. sackenii Von Röder; e. Bl. furcata sp. nov.; f. Bl. esakii Tokunaga; g. Bl. fenderiana; h. Bl. jonesi Johnson; i. Bl. nipponensis Alexander; d. Bittacomorphella thaiensis Alexander. All scale bars 1 mm except “ b ” (2 mm).

FIGURE 18. Bittacomorpha distributions. a. Bittacomorpha clavipes a 1. Nearctic; a 2. Central America; b. Bi. occidentalis. Star indicates cotype locality.