Ptychopteridae Osten Sacken, 1862

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 : 23

Family Ptychopteridae Osten Sacken, 1862

Ptychopterinae Osten Sacken, 1862: 12 (original description)

Ptychopterinae Schiner, 1862: 495 (description)

Ptychopteridae Osten Sacken, Hart 1895: 189 (elevation to full family rank) Liriopeidae Brues & Melander, 1915: 62 (replacement name, suppressed)

Diagnosis. Larva. Vermiform, eucephalous, metapneustic. Abdominal segments 1–3 with ventral prolegs. Anal division with prominent retractile respiratory siphon and two small, simple anal papillae. Pupa. Fusiform; two prominent respiratory organs, one hypertrophied longer than body of pupa; abdomen with rows of crenelated tubercles Adult. Head without ocelli, antenna with 13–21 flagellomeres. Wing with four branches of R reaching margin, 1–2 branches of M, 2 of CuA, 1 anal vein. Halter with prehalter at anterior base. Second abdominal segment extended. Male genitalia with paired epandrial claspers, large lateral ejaculatory processes, aedeagus with subaedeagal sclerite.

Description. Larva. Cranium eucephalous without incisions, with distinct frontoclypeal apotome and genae ( Fig. 6 ). Postgena present. Single stemmata present. Antenna present, one or two segmented. Labrum triangular, with two prominent labral brushes, epipharynx with premandible. Mandible with molar and incisor lobe, molar lobe massive, subquadrate or semicircular, incisor lobe triangular; prostheca and mandibular comb present. Maxilla with well sclerotized cardo and stipes, maxillary palpus peg-like; lacinia large, with prominent brushes, galea present. Prementum bottleneck shape, with prominent denticles at apex, postmentum forming bridge or fused to postgena. Thoracic segments readily distinguishable, cylindrical or weakly fusiform. Abdominal segments I–VI free, I–III each with pair of ventral prolegs, VII–IX formed into anal division housing respiratory siphon. Anal papillae paired, developed laterally as ribbon-like lobes on either side of anal division at the base of the terminal respiratory siphon; respiratory siphon variable in length, partially to fully retractile; two spiracles at apex. Adult. Head inverse triangular in anterior view, greater in height than depth, hypognathous, deflexed; chaetotaxy variable. Vertex weakly convex, with or without medial suture, broadly trapezoidal, ocelli absent. Compound eyes prominent, hemispherical, forming lateral margin of head, never holoptic. Occiput closely conforming to posterior margin of eye, weakly convex to foramen. Foramen approximately 1/3 of head diameter. Antennae elongate; scape cylindrical or ovoid tapering weakly at apex, anterior surface with prominent trichoid sensilla; pedicel subglobular with or without trichoid sensilla; flagellum with 13–21 flagellomeres, 1 st flagellomere longest, decreasing in length towards apex, densely clothed with fine sensilla. Facial sclerite small, trapezoidal, often indistinct. Clypeus prominent, undivided, triangular to sub trapezoidal, surface convex inflated. Gena bandlike under compound eye to clypeus, or reduced medially; subgena well developed with medial suture, anteriorly emarginated for base of labium. Labrum abbreviated, closely associated with apex of clypeus, externally forming small triangular or semicircular sclerotize nodule protruding anterior between clypeus and labium. Hypopharynx not apparent externally, closely fused with labium, forming moderately sclerotized trough extending to apex of clypeus, ending at base of external portion of labrum, equal in width to labrum; apex square, with salivary canal prominent. Mandibles absent. Maxillae not externally developed; maxillary palpus elongate, with five segments, first segment short, approximately same length as width, produced laterally to remaining palpal segments; second segment shorter than following two subequal segments, length of terminal segment variable, longer than preceding segments combined in some taxa; palpus with thick vestiture of trichoid sensilla, no specialized or modified sensilla. Labium with base fused to underside of clypeus; U-shaped in cross section, entirely membranous. Labella prominent, fused or separate, dorsal surface glabrous, lateral surfaces with prominent large trichoid sensilla, ventral surface with well-developed pseudotracheae. Thorax boxlike, narrow, approximately as tall as long, with variable, sparse setae. Cervix short, distinct; no sclerites dorsally or ventrally, laterocervicale weakly developed, lightly sclerotized. Antepronotum prominent, variable between subfamilies, often with dorsomedial lobules; antepronotal lobe well developed, fingerlike, subglobose at apex, postpronotum produced as narrow strip obscured by antepronotum. Postpronotum small, triangular, not meeting membranous region around anterior spiracle. Basisternum I fused medially into precoxal bridge, forming inverse trapezoid. Scutum quadrate in dorsal view, prescutum, presutural and postsutural scutum well delineated, medial suture prominent or weakly defined. Prescutum expanded forming anterior margin of scutum, narrowed to median strip extending posterior 2/3 length of scutum, never reaching posterior margin of scutum. Prescutual suture complete or incomplete posteriorly, with prominent prescutal pits. Presutural scutum quadrate, completely divided by posterior section of prescutum. Transverse suture distinct laterally, straight, merging with prescutal suture. Postsutural scutum with prominent anterolateral lobes created by medial emargination of prescutum, square anterior apices, lateral margins straight, posterior margin slightly convex. Supra-alar setae present in form of patch of trichoid sensilla produced at lateral margin of anterolateral lobe near anterior base of wing. Suprasquamal ridge prominent, rhomboid in shape, with cluster of post-alar trichoid sensilla produced dorsolaterally. Scutellum bulbously convex, shape from subcircular to elliptical ovoid, vestiture of elongate trichoid sensilla. Mediotergite of postnotum longitudinally hemispherical, with or without medial suture; Laterotergite of postnotum undivided, anterior margin rounded, posterior margin straight, with low node rising above halter, provided with a prominent patch of trichoid sensilla anterodorsally. Metanotum narrow, bandlike. Pleuron of thorax straight, not convex, largely glabrous, with setae on posterior sclerites in some taxa. Paratergite narrow, tapering at extremeties. Episternum rectangular in shape, anteroventral corner extended ventrally, episternal cleft prominent, often nearly obliterating anterodorsal section of anepisternum, some taxa with protuberance associated with anterior basalare; anepisternal suture partially developed to completely absent. Pleural suture straight, with deep narrow invagination below posterior basalare. Posterior basalare beanshaped, convex. Subalifer ovoid. Epimeron undivided, indistinguishably fused with meron, narrowly pentagonal in shape with ventral pointed apex between mid and hind coxae. Metapleuron subtrapezoidal, metapleural suture presence variable. Wing elongate, base narrow for approximately 1/8th length, expanding to uniform width to obtusely rounded apex, longitudinal wing venation relatively straight and parallel ( Fig. 7 ). Wing membrane with dense vestiture of fine evenly spaced microtrichia, macrotrichia present in some taxa. C strong along anterior margin, provided with evenly spaced stout trichoid sensilla in multiple rows, becoming weak or ending after apex, with elongate fine macrotrichia in single row. Sc extended approximately 1/2–3/4 the length of wing, arcing anterior to margin at apex; crossvein h located in basal 1/4th of wing. R initially branching approximately 1/2 of wing length, R1+2 paralleling margin, terminating subapically, R1 extending anterior to margin, R2 directed posteriorly fusing with R3; R s short, R3 parallel, reaching margin near apex of wing, r-m developed near R3 fork, short; R4+5 elongate, forking approximately midway along length, R4 and R5 reaching wing margin at apex. M straight, m-cu emerging approximately 2/3 of length to apex. CuA straight, deflected slightly posteriorly, forking near m-cu, base of CuA1 angled anterior to junction with m-cu, then deflexed slightly posteriorly in straight line to wing margin; CuA2 bent medially or sigmoidal anterolateral to wing margin. A1 reaching wing margin at 2/5 of length of wing, straight basally, then gently curved to wing apex distally. Halter large, length approximately equal to width of thorax, base with distinctive fingerlike prehalter. Legs narrow, elongate; similar form with length slightly increasing posteriorly. Coxae tapering cylindrical, longer than width of pleural sclerites, with distinct setal patterns on surface. Trochanter lopsided cylindrical, posteroventral margin emarginate. All posterior leg segments round in cross-section, densely clothed in stout macrotrichia. Femur expanded slightly near distal apex, longest leg segment. Tibia slightly shorter than femur, expanded slightly at proximal apex; tibial spur formula 1–2–2; foreleg spur variously developed, mid and hind leg acutely pointed, with elongate macrotrichia. Tarsus with five segments, acropod well developed; 1 st tarsomere elongate, 1/3rd–2/3rd length of tibia, tarsomeres 2–5 much shorter, segments moderately decreasing in length distally. 1 st tarsomere capable of folding back on 2nd in some taxa. Acropod with two opposed scythe-shaped claws with prominent pulvilliform empodium. Pregenital abdomen elongate, narrowed at base. Segment I of short, segment II elongate at least twice as long as next longest segment with sternite II subdivided approximately halfway along length, segments III–VII successively decreasing in length. Male. Genitalia forming distinct capsule, composed of segments VIII–XI, unrotated. Epandrium strongly developed, often bilobate, with distinct anterolateral epandrial claspers. Presence of cerci unclear (see discussion). Epiproct distinct or indistinct, hypoproct distinct, form variable. Parameres associated with base of gonocoxite, highly variable. Gonopods well developed, laterally produced, free from epandrium and hypandrium. Gonocoxite with prominent apodeme extending anterior beyond anterior margin of epandrium and hypandrium, gonocoxal lobe present or absent. Gonostylus simple or complex. Hypandrium subdivided into basal and terminal division. Aedeagal complex well sclerotized, composed of several discrete substructures. Sperm sac large, subglobular, ejactulatory apodeme well developed and laterally compressed. Lateral ejaculatory processes prominent, terminating in discoid apodeme. Aedeagal shaft composed of two lateral sclerites joined medially by a membranous region, lateral ejaculatory process present at base of aedeagal sclerite. Apex of aedeagus with distinct subaedeagal sclerite articulated on ventral surface. Female. Epigynium platelike or reduced. Epiproct apparent or reduced. Hypoproct present or absent. Cerci well developed, single segmented. Genital fork present. Hypogynium platelike, hypogynial valves prominent or reduced. Spermathecae present or absent.

Figures

FIGURE 6. Larval head structure. a. Bittacomorpha clavipes head capsule, dorsal view; b. postmentum / postgena, ventral view; c. Bi. occidentalis head capsule, dorsal view; d. postmentum / postgena, ventral view e. Bittacomorphella fenderiana head capsule, dorsal view; f. postmentum / postgena, ventral view. Scale bars 0.5 mm (a, c, e) and 0.25 mm (b, d, f). Abbreviations: cly clypeus; frcly ap frontoclypeal apotome; gen — gena; poc — postocciput.

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).