Bittacomorphella sackenii von Röder 1890

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 : 43-45

Bittacomorphella sackenii von Röder 1890

Bittacomorpha sackenii von Röder, 1890: 230 (original description) Bittacomorpha sackenii von Röder, 1895: 200 (redescription, key)

Bittacomorpha sackenii von Röder, Johnson 1905: 75 (key)

Bittacomorpha (Bittacomorphella) sackenii von Röder, Alexander 1916: 546 (key) Bittacomorphella sackenii von Röder, Alexander 1927: 9 (catalog)

Bittacomorphella sackenii von Röder, Peus 1958: 11 (catalog)

Bittacomorphella sackenii von Röder, Alexander 1965: 98 (catalog) Bittacomorphella sackenii von Röder, Alexander 1967: 171 (illustration)

Diagnosis. Adult ( Figs. 7 d, 13). Legs with white confined to distal tip of 1st, 2nd & 3rd tarsomeres. Epandrium quadrate, nearly flat, basal apical sclerite of aedeagus spiniform, distal portion of paramere forming semi-circular arc.

Description. Larvae and pupae unknown. Adult. Measurements (n=1). Overall length 10.45mm (9.68– 11.16mm); head width 0.75mm, height 0.71mm, length 0.43mm; antenna flagellum length 6.95mm, flagellomere proportions 1.00, 0.81, 0.87, 0.87, 0.87, 0.87, 0.87, 0.77, 0.72, 0.68, 0.64, 0.64, 0.59, 0.59, 0.50, 0.55, 0.46, 0.42, 0.09; maxillary palpus length 1.16mm, segment proportions 0.16, 1.0, 1.1, 0.8, 0.8; thorax length 1.38mm (1.43– 1.53mm), height 1.23mm (1.29–1.45mm), wing length 6.7mm, wing width 1.5mm, R3+4+5 stem 0.39mm, R4+5 stem 1.53mm, R4 after fork 1.23mm, R5 after fork 1.21mm, R3+4+5:R4+5-stem:R4 1.00, 3.92, 2.52; r-m 0.23mm, M distal to r-m 2.45mm, Mdistal:R3+4+5 5.90, 1.00; R4:Mdistal 0.42,1.00; CuA2 1.27mm; leg proportions, femur 1.0, 1.05, 1.15mm; tibia, 0.96, 0.99, 1.21; tarsomeres, foreleg 0.56, 0.18, 0.12, 0.04, 0.04; midleg 0.54, 0.19, 0.13, 0.03, 0.04; hind leg 0.66, 0.24, 0.16, 0.03, 0.04; abdomen length 8.26mm, male tergite proportions 1.00, 3.55, 2.14, 1.97, 1.63, 0.89, 0.13; male genitalia width 0.54mm, height 0.57mm. Frons medial suture weakly developed. Antennal scape with three setiform sensilla midway along anterior margin; 19–20 flagellomeres. Face incised by clypeus to antennal bases. Hypopharynx triangular flattened, directed anteriorly. Labella D-shaped partially fused medially, forming ovoid pad. Antepronotum weakly developed, narrow low ridge. Scutum glabrous, pollinose, fuscous. Scutellum muddy yellow. No prescutellum present. Mediotergite ruddy-brown. Paratergite poorly developed, narrow, scythelike. Sub-paratergal membrane subquadrate, lightly sclerotized; anepisternal suture absent. Suture of epimeron and metapleuron sinuous, rapidly becoming indistinct ventrally. Metapleural suture arcing to halter. Pleurites ruddy brown. Wing membrane with sparse macrotrichia along apical 1/6of wing in cells Sc, R1, R3, R4, R5, M; Vein C to wing apex, Sc, R s, R1, R3, R4 & R5 after fork with macrotrichia; alula undeveloped. Posthalter weakly developed, broadly triangular, with several long translucent sensilla apically, webbing to halter well-developed. Coxae yellow, overall leg coloration brown. White banding confined to distal tip of 1st, 2nd & 3rd tarsomeres. Empodium notched proximally. Abdomen chocolate brown. Male. Epandrium about 1.5x as wide as long, nearly flat across surface, lateral margins slightly bowed laterally, curvature becoming more pronounced towards posterior margin, internal fold weakly developed (often absent), posterior margin weakly emarginate medially, posteromedial stylus obtuse triangle directed posteriorly. Epandrial claspers not inflated, abruptly tapering to subacute point, curved sub-circularly dorso-anteriorly. Paramere base laterally compressed, distal portion stylate, curved semicircular ventrally, pointed apex. Gonocoxite conical, expanding to gonostylus. Gonostylus 1.5x length of gonocoxite, slightly expanded at base, inner apex sensilla single row of 10–11 along dorsomedial margin, shifting from directly medial posteriorly towards dorsal anteriorly; three sensilla at base medially. Basal division of hypandrium medial suture extending to lacrimiform membranous region; terminal division well-articulated, proximal portion cupped to pouch longer than wide; apical portion with lateral margins fused dorsally forming short invagination. Sperm pump with membranous windows weakly developed. Ejaculatory apodeme spathate, dorsal margin convex, apex tapering to point. Lateral ejaculatory process triangular, winglike, swept-back; discoid apodeme rounded; ventral lobe small, rounded, directed posteriorly, largely contiguous with remainder. Aedeagal sclerites weakly tapered, ventral apical apodeme heavily rounded, less sclertized distally. Subaedeagal sclerite internally rectangular, weakly sclerotized anteriorly; external portion acute spine, directed posteriorly. Female (only available from a lateral slide mount). Epigynium subtrapezoidal tapering towards posterior margin; posterior margin straight. Cerci short, 1.75x length vs. height, ovoid, ventral margin not potbellied. Hypogynium broad at base; posterolateral apices of posterior margin formed to rounded triangular lobes, medial emargination very weakly developed.

Material examined. UNITED STATES. CALIFORNIA. Inyo Co. Big Pine Creek , 11.vii.1957, coll. C.P. Alexander [slide 3 ♂; USNM] ; Mariposa Co. Yosemite, Mariposa grove, 22.vii.1946, coll. C.P. Alexander [slide 1 ♀; USNM]; Mono Co. Mono Lake , 24.vii.1911, coll. J.M. Aldrich [pinned 1 ♂; USNM] .

Taxonomic notes. The holotype of Bl. sackenii is not located in the collection of the Martin Luther Universität Halle-Wittenberg (where the majority of von Röder’s type material is housed), but probably resides with the collection of H. K. Morrison (Karla Schneider, pers. comm.). The authors were unable to determine where the Morrison collection is housed; therefore, the holotype was not examined. Alexander (1967) also notes he was unable to locate the holotype. However, von Röder records the specimen as being collected in: (Sierra) Nevada. America septentrionalis. (H. K. Morrison). There is only one species of Bittacomorphella in the Sierra Nevada, whose range does not overlap with other species of Bittacomorphella , so assignment of this species is not problematic.

Bittacomorphella sackenii is the nominate member of the Bl. sackenii group, which includes Bl. pacifica and Bl. furcata . Before the description of Bl. pacifica and Bl. fenderiana all western Nearctic Bittacomorphella were determined to Bl. sackenii , and many of these incorrect determination labels remain in collections. Bittacomorphella sackenii can be distinguished from these species by the structure of the male genitalia: the epandrium is platelike and square (versus bilobate and hexagonal in Bl. fenderiana ) and the parameres undivided (versus bifurcate in Bl. furcata ) and arched dorsally (versus straight in Bl. pacifica ).

Distribution. Fig. 19 b.

Figures

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 19. Nearctic Bittacomorphella distributions. a. Bl. pacifica; b. Bl. furcata (star & square) and Bl. sackenii (circles); c. Bl. fenderiana; d. Bl. jonesi. Stars indicates type locality.