Schizonyxhelea Clastrier. Study 1984
Creators: name: Borkent, Art
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Ceratopogonidae
Schizonyxhelea

description: Schizonyxhelea Clastrier
(Figs. 11H, 20E–F, 25C, 29T, 36C, 44L–M, 49C, 60B, 74F–G)
DIAGNOSIS: Only pupa of Ceratopogonidae with the terminal process with a posterior row of thick spines and no other thick spicules present (Fig. 74G); also unique in the thoracic D-1-T much more stout than the other dorsal seta (Fig. 29T).
DESCRIPTION: Habitus as in Fig. 11H. Total length = 1.19–2.16 mm. Without larval exuviae retained on abdomen. Exuviae with flagellum appressed against lateral margin of face (as in Fig. 15D). Ecdysial tear around base of antenna (as in Figs. 15D, 79E); along prothoracic extension. Head: Dorsal apotome (Figs. 20E–F), without ventral line of weakness, without dorsomedial tubercle, without central dome; dorsolateral cephalic sclerite (as in Fig. 13B) separated from scutum by thin cuticle, separate from scutum upon emergence, each side separated medially by dorsal apotome in whole pupa; mouthparts (Fig. 25C) with mandible well-developed, lacinia absent; palpus extending posterior to posterolateral margin of labium; labium separated medially by labrum, hypopharynx; apex of antenna (Fig. 36C) posterior to posterior extent of midlength portion of midleg (portion lateral to mesosternum); sensilla: dorsal apotomals (Figs. 20E–F)—1 moderately elongate seta, 1 campaniform sensillum; dorsolateral cephalic sclerite sensilla—1 seta, no campaniform sensillum; clypeal-labrals (Fig. 25C)—2 minute setae; oculars (Fig. 25C)—2 elongate setae. Thorax: Prothoracic extension (Fig. 25C) wide, well-developed, extending from palpus to antenna; mesonotum with short tubercles, extending posteromedially, completely dividing metathorax medially (Fig. 49C); respiratory organ (Figs. 44L–M) length/width = 4.92–7.08, elongate, slender, somewhat flattened dorsoventrally, with pores closely abutting at apex of respiratory organ, arranged in single row, with additional more basal pores, outer surface smooth, with moderately elongate pedicel, base with short posteromedial apodeme, membranous base of respiratory organ moderately elongate, tracheal tube straight to slightly curved along length, with spirals restricted to base, distally with plate; wing (Fig. 36C) without apical tubercle or angle, separated medially by fore-, midlegs; halter apex and hind leg (similar to Fig. 32L) broadly abutting; halter apex just posterior to knob-like extension of tergite 2; legs (Fig. 36C) with lateral margin of foreleg near midlength of wing evenly curved; hind leg visible at lateral margin of wing (as in Fig. 32L); with apex of foreleg moderately anterior to apex of midleg; apex of hind leg abutting apex of midleg laterally; sensilla: anteromedials—2 setae, 1 thicker than other; anterolaterals—3 setae; dorsal setae (Fig. 29T)—D-1-T, D-2-T, D-4- T setae with D-1-T stouter than others, D-3-T campaniform sensillum, D-5-T absent, D-3-T posteromedial to D-4- T; supraalar 2—campaniform sensillum; metathoracics (Fig. 49C)—1 seta, 2 campaniform sensilla; M-3-T near anterior margin of metathorax. Abdomen: without pigmentation pattern, segment 2 as wide or slightly wider than segment 3, segments with undivided, thin to thick setae, with slightly rounded to pointed, or serrate short tubercles, tergites or sternites entire, each without membranous disc; segment 9 (Figs. 74F–G) with two dorsomedial short tubercles, one anterior to other, terminal processes closely approximated basally, each projecting posterodorsolaterally, tapering to pointed apex, with posterior row of spines; sensilla: tergite 1 (Fig. 49C) with 3, 5 setae, 2–3 campaniform sensilla, including 1 lateral sensillum, 1 seta close, D-7-I situated posteriorly near D-8-I; segment 4 (Fig. 60B)—D-2-IV, D-3-IV short setae on serrate tubercles; D-5-IV barely visible short seta (or perhaps a campaniform sensillum), D-8-IV, D-9-IV short seta; D-5-IV, D-4-IV, D-7-IV, D-8-IV, D-9-IV on short, serrate tubercles, posterior dorsal sensilla in transverse row, arranged medially to laterally: D-5-IV, D-4-IV, D-7-IV, D-8- IV; L-1-IV short seta, on pointed tubercle, well anterior of posterior lateral setae; L-2-IV, L-3-IV short setae, L-4- IV thick seta on serrate tubercles, V-5-IV, V-6-IV, V-7-IV moderately elongate setae on serrate tubercles; segment 8 without D-3-VIII, without L-1-VIII; segment 9 (Figs. 74F–G)—with D-5-IX campaniform sensillum, D-6-IX possibly absent (not discernable).
DISTRIBUTION AND HABITAT: The genus Schizonyxhelea is known from nine species from the New World and Oriental Regions (Borkent 2014, additions below). Schizonyxhelea bulla has been reared from mud from the margins of a bog, from the grassy margin of a marsh and from mud, pond weeds and Sphagnum (Thomsen 1937, Wirth & Grogan 1981). Borkent (2000a) found a larva of S. forattinii in wet mud in a small seep which flowed into the outflow of a larger spring in Costa Rica.
TAXONOMIC DISCUSSION: This genus previously included only two Neotropical species (Borkent 2014) (Tables 2–3). In his description of the larva and pupa of S. forattinii, Borkent (2000a) pointed out the striking similarities especially between the pupae of Schizonyxhelea forattinii Wirth & Grogan and Stilobezzia bulla Thomsen. A number of these are here interpreted as synapomorphies of the genus (characters 24, 54, 76, 79).
Nearly all male Schizonyxhelea have a unique and distinctive transverse band of cuticle ventral to the parameres (at about midlength), that is clearly a synapomorphy of the genus. It is uncertain what this structure is, considering that it is likely that a very reduced set of more ventrally located small sclerites is homologous to the aedeagus of other Ceratopogonidae. The male of S. forattinii lacks the ventral transverse band of cuticle but does have a pair of broad extensions from the midlength of the gonocoxites which extend dorsally to the parameres and overlap medially. A further synapomorphy of all species examined here is the reduced set of small sclerites making up the aedeagus. Some other adult features may be synapomorphies (Borkent 2000a) but further study is needed.
Historically, the shape of the claws of female adults has been used as a primary character to identify and recognize genera. The females of the two species originally placed in Schizonyxhelea (S. forattinii, S. guyana) had equal claws on each leg, a single, bent spermatheca and reduced wing venation. The additional species recognized here have single claws on each leg (with a basal tooth) and are similar to those of Stilobezzia, with two welldeveloped spermathecae and wings with two radial cells. I have examined a female from Costa Rica which has a wing venation identical to those of S. forattinii and S. guyana but has single claws and two spermathecae. I have examined other, non-related, Stilobezzia with equal claws and the same variation occurs, for example, in Serromyia (Borkent & Bissett 1990) and Alluaudomyia (pers. obs. unnamed species). Clearly, single or equal claws are variable within these genera and should be used with caution in distinguishing other genera.
On the basis of the distinctive male genitalia and pupal synapomorphies, this genus now includes:
Schizonyxhelea brevicostalis (Das Gupta & Wirth), 1968: 28 (Stilobezzia). Malaysia, new combination. Schizonyxhelea bulla (Thomsen), 1935: 289 (Stilobezzia). USA, new combination.
Schizonyxhelea caribe (Lane & Forattini), 1958: 208 (Stilobezzia). Panama, new combination.
Schizonyxhelea diminuta (Lane & Forattini), 1958: 209 (Stilobezzia). Panama, new combination.
Schizonyxhelea forattinii Wirth & Grogan, 1988: 81. Brazil.
Schizonyxhelea guyana Clastrier, 1984: 2. French Guiana.
Schizonyxhelea obscura (Lane & Forattini), 1958: 216 (Stilobezzia). Panama, new combination.
Schizonyxhelea panamensis (Lane & Forattini), 1958: 218 (Stilobezzia). Panama, new combination. Schizonyxhelea thomsenae (Wirth), 1953: 83 (Stilobezzia). USA, new combination.
Schizonyxhelea scutata (Lane & Forattini), 1961: 92 (Stilobezzia). Panama, new combination.
Harris (1981) described seven species of Stilobezzia from Australia. Her species 6 is a Schizonyxhelea, with its characteristic features (i.e. thoracic sensilla D-1-T short and stout, distribution of abdominal 4 sensilla with each on a serrate tubercle, posteromedial margin of terminal process with row of spines). I have also examined a reared series of an unnamed species from Laos and there are a number of unnamed species (based on adults) from Costa Rica. Clearly the genus is more diverse and broadly distributed than was previously recognized.
Wirth & Grogan (1981) described the pupa of S. bulla (as a Stilobezzia) but did not describe or illustrate the posterior row of spines which are actually present on the terminal process. Borkent (2000a) missed CL-1-H and CL-2-H on the mouthparts of the pupa as well as D-9-IV on abdominal segment 4 (the single specimen was dirty). Stilobezzia insolita Das Gupta & Wirth from Malaysia is known only as a female but it has a reduced wing venation and an apically swollen and basally curved spermatheca, all similar to some Schizonyxhelea (e.g. S. forattinii). However, until further study, this species remains in Stilobezzia.
MATERIAL EXAMINED: S. bulla: 1 pupal exuviae, Algonquin Park, Ontario, Canada, 8-VI-1960 (USNM); 1 pupal exuviae, Patuxent Rescue Center, Prince George’s County, Maryland, USA, 17-V-1976 (USNM); 2 pupal exuviae, as previous locality, 4-VI-1976 (USNM); 1 pupal exuviae, as previous locality (WLGC); 1 pupal exuviae, Allegany State Park, New York, USA, 28-V-1963 (WLGC); 2 pupal exuviae, McLean Reserve, Tompkins County, New York, USA, 18-VI-1963 (WLGC); 1 pupal exuviae, Bergen Swamp, Genesee County, New York, USA, 14- VI-1963 (WLGC); 2 pupal exuviae, Research Station Pond, Newcomb, New York, USA, 30-VI-1958 (NYSM); 1 pupal exuviae, Meadow Hole, E. Berne, New York, USA, 29-VI-1963 (NYSM); 1 pupal exuviae, Wet Meadow Hole, E. Berne, New York, USA, 24-VI-1963 (NYSM); 1 pupal exuviae, Mitchell’s Meadow Pool, E. Berne, New York, USA, 29-VII-1963 (NYSM); 1 pupal exuviae, Lake Jimmy, Tahawus, New York, USA, 24-VI-1959 (NYSM); 1 pupal exuviae, Mud Pond Outlet, Blue Mountain Lake, New York, USA, 8-VI-1959 (NYSM); 1 pupal exuviae, Sphagnum Bog, Blue Mountain Lake, New York, USA, 7-VI-1959 (NYSM); 1 pupal exuviae, Salmon River, Blue Mountain Lake, New York, USA, 8-VI-1959 (NYSM); 1 pupal exuviae, Beartown Mt. Bog, Virginia, 16-VIII-1977 (VPIC); 1 pupal exuviae, Flag Glade, Pocahontas County, Virginia, USA, 24-VI-1976 (VPIC); 1 pupal exuviae, Jefferson Nt. Forest, Little Meadows, Giles County, Virginia, USA, 6-IX-1976 (VPIC). S. forattinii: 1 pupal exuviae, 2 km NE Tarcoles, Costa Rica, 17-XII-1993 (reared from larva) (CNCI). S. sp.: 1 pupal exuviae, Moung Sayaboury, Sayaboury Province, Laos, 22-II-1967 (BPBM); 1 pupal exuviae, as previous locality, 19-II- 1967 (BPBM); 5 pupal exuviae, Ban Na Tak, Moung Sayaboury, Sayaboury Province, Laos, 9-XII-1967 (BPBM).
description: Published as part of Borkent, Art, 2014, The Pupae of the Biting Midges of the World (Diptera: Ceratopogonidae), With a Generic Key and Analysis of the Phylogenetic Relationships Between Genera, pp. 1-327 in Zootaxa 3879 (1) on pages 64-66, DOI: 10.11646/zootaxa.3879.1.1, http://zenodo.org/record/4949051