Stilobezzia Kieffer
Creators: name: Borkent, Art
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Ceratopogonidae
Stilobezzia

description: Stilobezzia Kieffer
(Figs. 15D, 19P, 20A–D, 25A–B, 29S, 32L, 36A–B, 44E–K, 49B, 59C, 60A, 74C–E)
DIAGNOSIS: Only pupa of Ceratopogonidae with the thoracic sensilla D-1-T, D-2-T, D-3-T and D-4-T all present on flat cuticle (not on tubercles) and close to one another and with D-5-T either absent or, at most, a minute pit lacking any seta (Fig. 29S).
DESCRIPTION: Total length = 1.69–3.53 mm. Without larval exuviae retained on abdomen. Exuviae with flagellum appressed against lateral margin of face, in some against wing (Figs. 15D, 32L). Ecdysial tear posterior to base of antenna (Figs. 15D, 79E); along prothoracic extension. Head: Dorsal apotome (Figs. 19P, 20A–D), with 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 (Figs. 25A–B) with mandible well-developed, fused to surface, lacinia absent; palpus extending equal to or just posterior to posterolateral margin of labium; labium entire or separated medially by labrum, hypopharynx; apex of antenna (Figs. 36A–B) just anterior to posterior to, posterior extent of midlength portion of midleg (portion lateral to mesosternum); sensilla: dorsal apotomals (Figs. 19P, 20A–D)—1 short to elongate seta, 1 campaniform sensillum; dorsolateral cephalic sclerite sensilla—1 seta, 1 campaniform sensillum; clypeal-labrals (Figs. 25A–B)—absent, with 1 minute seta,1 campaniform sensillum or 2 setae; oculars (Figs. 25A–B)—1 seta, 1 campaniform sensillum or 2 setae or 2 setae, 2 campaniform sensilla. Thorax: Prothoracic extension (Figs. 25A–B) wide, well-developed, extending from palpus to antenna; mesonotum without tubercles, not extending posteromedially to extending posteromedially, completely dividing metathorax medially (Fig. 49B); respiratory organ (Figs. 44E–K) length/width = 4.00–9.00, variable, elongate, slender, somewhat flattened or circular in cross-section, with pores closely abutting or slightly separated at apex of respiratory organ, arranged in single row, with or without additional, more basal pores, outer surface smooth, without or with short, wide to elongate, slender pedicel, base without posteromedial apodeme, membranous base of respiratory organ short to moderately elongate, tracheal tube straight to slightly curved along length, with spirals restricted to base, distally with plate; wing (Figs. 36A–B) without apical tubercle or angle, separated medially by fore-, midlegs; halter apex and hind leg (Fig. 32L) broadly abutting; halter apex extending posteriorly to 1/4 length of tergite 2; legs (Figs. 36A–B) with lateral margin of foreleg near midlength of wing evenly curved; hind leg visible at lateral margin of wing (Fig. 32L); with apex of foreleg slightly to moderately anterior to apex of midleg; apex of hind leg slightly ventral to, partially abutting or just abutting apex of midleg laterally; sensilla: anteromedials—2 setae; anterolaterals—2–3 setae; dorsal setae (Fig. 29S)—D-1-T, D-2-T, D-4-T setae, D-3-T campaniform sensillum, D-5-T absent or, at most, a minute pit lacking any seta, with D-1-T, D-2-T, D-3-T, D-4-T all present on flat cuticle, closely approximated, D-3-T posteromedial to posterolateral to D-4-T; supraalar 2—campaniform sensillum; metathoracics (Fig. 49B)—1 very small to long seta, 2 campaniform sensilla; M-3-T near anterior margin of metathorax. Abdomen: without pigmentation pattern or, segment 2 as wide or slightly wider than segment 3, segments with or without bifurcating setae, with bilobed, bifid or rounded to pointed, short to moderately elongate tubercles, tergites or sternites entire, each without membranous disc; segment 9 (Figs. 74C–E) not strongly modified, terminal processes closely approximated basally, each projecting posteriorly to laterally, tapering to pointed apex, in some elongate, slender; sensilla: tergite 1 (Fig. 49B) with 7–8 setae, 2 campaniform sensilla, including 3 lateral sensilla (4 in S. enigma), D-2-I, D-3-I closely approximated, D-7-I situated posteriorly near D-8-I; segment 4 (Figs. 59C, 60A)—D-2-IV, D-3-IV short or moderately elongate setae or D-3-IV absent, without or on low tubercles; D-5-IV, D-8-IV, D-9-IV short to elongate simple or bifurcating setae or D-5-IV, D-9-IV absent; on short to moderately elongate, separate tubercles or D-7-IV, D-8-IV on single tubercle, posterior dorsal sensilla in transverse row, arranged medially to laterally: D-5-IV, D-4-IV, D-7-IV, D-8-IV, D-9-IV to only D-4-IV, D-7-IV, D-8-IV present, L-1-IV absent or (rarely) short to elongate seta on short to elongate tubercle, in nearly transverse row with other lateral setae, arranged L-2-IV, L-3-IV, L-4-IV; L-1-IV, L-2-IV, L-3-IV, L-4-IV short to elongate setae on pointed or bifid tubercles, V-5-IV, V-6-IV, V-7-IV short to elongate, simple or bifurcating setae on short, rounded to elongate tubercles, in some with V-6-IV, V-7-IV on single tubercle; segment 8 without D-3-VIII, without L-1-VIII; segment 9 (Figs. 74 C-E)—with D-5-IX, D-6-IX campaniform sensilla.
DISTRIBUTION AND HABITAT: The genus Stilobezzia is known from 341 species from every Region worldwide (Borkent 2014, minus species here transferred to Schizonyxhelea). Immatures are in a wide variety of aquatic and sem-aquatic habitats including springs, swamps, bogs, fens, rice fields, rock pools, treeholes, soil in a tidal marsh, and the margins of ponds, lakes, streams and rivers.
TAXONOMIC DISCUSSION: There are only 29 species of Stilobezzia known as pupae (Tables 2–3). As indicated below, obtaining the pupae of additional species will likely lead to a better understanding of the cladistic relationships within this group.
The earliest description of a Stilobezzia pupa may be that by Packard (1871) who described it as a Tanypus (Chironomidae). Although clearly a ceratopogonid, the taxon cannot be identified with certainty although the overall habitus (especially the lateral direction of the terminal processes) suggests it is a species of Stilobezzia. However, it would be informative if this species (noted as common at that time) was resampled at Clear Lake, California to confirm the identification.
The pupae of Stilobezzia species are strikingly diverse, showing considerable variation, for example in the number and distribution of sensilla of abdominal segment 4 (Figs. 59C, 60A). The shape of the respiratory organs (Figs. 44E–K) and terminal processes (Figs. 74C–E) also vary broadly. The remarkably modified respiratory organs of S. rabelloi (Fig. 44I) and S. poikiloptera are used to pierce the submerged roots of aquatic plants to obtain oxygen for the pupa (Borkent & Craig 2001).
Ronderos et al. (2012) described a peculiar species of Stilobezzia as S. enigma and discussed it's phylogenetic placement, concluding that it likely belongs within the subgenus S. (Stilobezzia), based on the lack of any indication of tubercles on the dorsum of the thorax (otherwise bearing the dorsal sensilla). Within the analysis here, the pupa has synapmorphies 27, 29 and 39 and confirms its placement within the genus. The presence of four lateral sensilla on tergite 1, all of which are setae, is a feature unique with the Ceratopogonidae. The presence of D–7-I near D-2-I and D-3-I is unique within the genus (see character 53).
Cazorla et al. (2006) drew the sensilla of abdominal segment 4 of S. fiebrigi with more sensilla than are known in any other Ceratopogonidae and this species should be reexamined to confirm their presence and distribution.
Harris (1981) described seven species of Stilobezzia from Australia, six of which were considered new and provided a key to these. However, her species 6 is here recognized as a member of Schizonyxhelea, with its characteristic features (see below under that genus).
Based on the conclusion that Schizonyxhelea is clearly monophyletic and most closely related to Baeodasymyia, some species previously recognized as members of Stilobezzia are now placed in Schizonyxhelea as new combinations (see below under that genus).
The phylogenetic relationships between species of Stilobezzia are uncertain and the genus warrants a detailed cladistic analysis to test the reality of the current division into four subgenera. Clastrier (1976) recognized that the current subgenera (at that time with three subgenera) were artificial and correctly suggested further character states (primarily of the antennae, wings and thoracic chaetotaxy) to interpret the group. Unfortunately, he did not interpret the newly reported features cladistically and the result was a difficult to interpret new arrangement of the species. Wirth & Grogan (1988) did not use the system suggested by Clastrier (1976) and named an additional subgenus for two distinctive Australian species. Some pupal features are likely important in future phylogenetic analyses of this interesting genus. For example, the dorsal setae arising from the mesonotum of Ceratopogonidae pupae nearly always arise from at least low tubercles. Within Stilobezzia, three species of the subgenus S. (Acanthohelea) (S. gracilis, S. lutea, and S. orientis) have the setae arising from very low tubercles. Those of the subgenus S. (Stilobezzia), however, have the setae arising directly from the cuticle and this unique feature indicates their monophyly (S. antennalis, S. coquillettii, S. diversa, S. flavirostris, S. glauca, S. limnophila, S. navaiae, S. pallidiventris, S. papillata, S. pictipes, S. rabelloi, and S. sybleae). Two species of S. (Acanthohelea), S. papillata (examined here) and S. ochracea (as described by Kettle & Lawson 1952) also have slender setae arising directly from the cuticle, indicating that at least these two species of S. (Acanthohelea) are more closely related to species of the subgenus S. (Stilobezzia) than they are to other S. (Acanthohelea). It is worth noting that S. papillata and S. ochracea have unique elongate spicules on the apices of their respiratory organs, certainly indicating that these two are sister species.
Three of the species of S. (Acanthohelea), namely S. gracilis, S. lutea, and S. orientis, have most of the setae on abdominal segments 3–7 arising from distinctive bifid tubercles in which each half of the tubercle is very slender and about as long as the seta borne by it. This feature is nearly unique in the Ceratopogonidae, otherwise similar to that in some species of Ceratopogon (where it is clearly independently derived). The feature is, therefore, derived. The two species of S. (Acanthohelea), S. papillata and S. ochracea, which, as indicated above, are likely related to species of the subgenus S. (Stilobezzia) lack this feature. Furthermore, the strongly modified pupa of S. (S.) rabelloi (Borkent & Craig 2001) does have bifid tubercles although they are much larger than those of S. gracilis, S. lutea, and S. orientis. This suggests that S. rabelloi is actually a member of S. (Acanthohelea). Although this species lacks the defining presence of macrotrichia on the apex of the adult wing, it does bear strong setae on veins R and R 3, which are otherwise lacking in the subgenus S. (Stilobezzia) but are present in S. (Acanthohelea).
MATERIAL EXAMINED: S. antennalis: 7 pupal exuviae, Salmon Arm, British Columbia, Canada, 7-VI- 1988 (CNCI); 1 pupal exuviae, 3 km E of Salmon Arm, British Columbia, Canada, 9-VI-1988 (CNCI); 1 pupal exuviae, 30 km N of Nakusp, British Columbia, Canada, 5-VII-1990 (CNCI); 1 pupal exuviae, Plummer’s Island, Montgomery County, Maryland, USA, 4-VI-1976 (WLGC); 2 pupal exuviae, Patuxent Wildlife Refuge, Prince George’s County, Maryland, USA, 5-VII-1977 (USNM); 1 pupal exuviae, as previous locality, 24-V-1977 (USNM); 1 pupal exuviae, Highlands Lake Ravenel, Macon County, North Carolina, USA, 10-VI-1986 (USNM); 2 pupal exuviae, Grandview Natural Preserve, Hampton, Virginia, USA, 30-VII-1976, 25-VIII-1976 (VPIC); 1 pupal exuviae (in glycerin), Grandview Natural Preserve, Hampton, Virginia, USA, 30-VII-1976 (VPIC); 2 pupal exuviae, Dyke Marsh, Alexandria, Virginia, USA, 3-VI-1975 (WLGC); 1 pupal exuviae, no locality, 6-VIII-1953 (USNM). S. coquilletti: 1 pupal exuviae, Farmer Agnew’s Property, Montgomery County, Virginia, USA, 22-VIII- 1975 (VPIC); 2 pupal exuviae, Hasler Farm, Co. Rt. 763, Rockingham County, Virginia, USA, 24-VII-1975 (VPIC); 1 pupal exuviae, Balboa, Panama, 3-IX-1942 (USNM); 1 pupal exuviae, Balboa, Panama, VIII-1942 (USNM). S. diversa: 1 pupal exuviae, Patuxent Wildlife Refuge, Prince George’s County, Maryland, USA, 24-V- 1977 (USNM). S. flavirostris: 1 pupal exuviae, Maikov, Rovno Province, Ukraine, 29-V-1974 (ZIN). S. glauca: 1 pupal exuviae, Patuxent Rescue Center, Prince George’s County, Maryland, USA, 13-V-1976 (USNM); 3 pupal exuviae, 4.5 mi. E of Corapeake Road from Desert Road, Camden County, North Carolina, USA, 29-VII-1976 (VPIC); 1 pupal exuviae, Dyke Marsh, Alexandria, Virginia, USA, 29-VI-1952 (WLGC); 1 pupal exuviae, Falls Church, Virginia, USA, 30-VI-1951 (WLGC); 1 pupal exuviae, Dyke Marsh, Alexandria, Virginia, USA, 29-VI- 1952 (WLGC); 1 pupal exuviae, Watoga State Park, Pocahontas County, Virginia, USA, 25-VI-1976 (VPIC); 1 pupal exuviae, Blackwater River State Forest Biological Station, Santa Rosa County, Florida, USA, 23-V-1973 (WLGC); 1 pupal exuviae, Rock Springs, Orange County, Florida, USA, 21-IV-1970 (USNM). S. gracilis: 1 pupal exuviae, no locality/date (ZSMC). S. limnophila: 1 pupal exuviae, Jam Tin Creek, Malelane,East Transvaal, South Africa, 2-XII-1973 (NMSA); 2 pupal exuviae, Sterk River, S.W., Potgietersrus, Transvaal, South Africa, 3-I-1974 (USNM). S. lutea: 1 pupal exuviae, 10 km W. Old Chelsea, Quebec, Canada, 15-VII-1986 (CNCI); 1 pupal exuviae, Patuxent Rescue Center, Prince George’s County, Maryland, USA, 17-V-1976 (WLGC); 1 pupal exuviae, Beltsville, Prince George’s County, Maryland, USA, 28-V-1975 (WLGC); 2 pupal exuviae, Mud Creek, Tompkins County, Freeville, New York, USA, 19-VI-1963 (USNM); 2 pupal exuviae, Hamilton-Essex, Newcomb, New York, USA, 17-VI-1959 (NYSM); 1 pupal exuviae, as previous locality, 22-V-1959 (USNM); 1 pupal exuviae, as previous locality, 28-VI-1958 (NYSM); 1 pupal exuviae, as previous locality, 25-V-1959 (NYSM); 1 pupal exuviae, as previous locality, 24-V-60 (NYSM); 1 pupal exuviae, as previous locality, 29-V-1959 (NYSM); 1 pupal exuviae, as previous locality, 11-V-1959 (NYSM); 1 pupal exuviae, Letchworth State Park, New York, USA, 13- VI-1963 (USNM); 2 pupal exuviae, 1 km downstream lower Cascade Falls, Giles County, Virginia, USA, 3-VII- 1977 (VPIC); 1 pupal exuviae, Alexandria, Virginia, USA, 13-V-1958 (WLGC). S. navaiae: 13 pupal exuviae (of paratypes), Cranberry Lake, St. Lawrence County, New York, USA, 25-VI-1963 (USNM); 4 pupal exuviae, 5 km E of Danby, Vermont, USA, 25-VI-1986 (CNCI); 1 pupal exuviae, 5 km E. Danby, Vermont, USA, 25-26-VI-1986 (CNCI). S. orientis: 1 pupal exuviae (of holotype), Burgeshall, Hazyview, East Transvaal, South Africa, 3-XII- 1973 (NMSA). S. pallidiventris: 5 pupal exuviae, McLean Reserve, Tompkins County, New York, USA, 18-VI- 1963 (2 WLGC, 1 CNCI, 2 USNM); 3 pupal exuviae, Allegany State Park, New York, USA, 28-V-1963 (1 WLGC, 1 CNCI, 1 USNM); 1 pupal exuviae, Ivory, Chautauqua County, New York, USA, 31-V-1963 (USNM); 5 pupal exuviae, Ona, Hardee County, Florida, USA, 6-XI-1983 (USNM). S. papillata: 1 pupal exuviae, Tien-Shan, Issyk-Kul Province, Kyrgyzstan, 24-VI-1971 (ZIN); 2 pupal exuviae, Cholpon-Atinka river, Tien-Shan, Kyrgyzstan, 24- VI-1971 (ZIN). S. pictipes: 3 pupal exuviae, Hillman Rr. Margin, Darban, Western Australia, Australia, 29-X-1985 (ANIC); 1 pupal exuviae, Warriewood, New South Wales, Australia, 29-IX-1956 (ANIC); 2 pupal exuviae, as previous locality, 4-XI-1956 (ANIC); 1 pupal exuviae, Griffith, New South Wales, Australia, 16-XI-1956 (ANIC). S. rabelloi: 3pupal exuviae, 5 km NE of Tarcoles, Costa Rica, 26-VII-1993 (CNCI); 1 pupal exuviae, as previous locality, 20-VII-1993 (CNCI). S. sybleae: 1 pupal exuviae, McLean Reserve, Tompkins County, New York, USA, 18-VI-1963 (WLGC); 1 pupal exuviae, Dismal Swamp, Camden County, North Carolina, USA, 25-III-1976 (VPIC); 12 pupal exuviae, Gainsville, Alachua County, Florida, USA, 20-IV-1967 (5 USNM, 5 WGLC, 2 CNCI); 1 pupal exuviae, Rock Springs, Orange County, Florida, USA, 21-IV-1970 (USNM); 1 pupal exuviae, Dyke Marsh, Alexandria, Virginia, USA, 29-VI-1952 (USNM); 1 pupal exuviae, Dyke Swamp, Alexandria, Virginia, USA, 11- VI-1952 (USNM). S. thomsenae or S. bulla: 1 pupal exuviae, Montgomery County, Virginia, USA, 23-VI-1977 (VPIC). S. sp.: 1 pupal exuviae, Negrito Creek Reserve, Catron County, New Mexico, USA, 21-IX-1992 (CNCI); 1 pupal exuviae, Grandview Natural Preserve, Hampton, Virginia, USA, 30-VII-1976 (VPIC); 3 pupal exuviae, 3 km N of Caldera, Costa Rica, 17-XII-1993 (CNCI); 1 pupal exuviae, Moung Sayaboury, Sayaboury Province, Laos, 20-VIII-1967 (BPBM); 1 pupal exuviae, as previous locality, 4-III-1968 (BPBM); 1 pupal exuviae, Houng River, Moung Sayaboury, Sayaboury Province, Laos, 30-V-1967 (BPBM); 2 pupal exuviae, Moung Sayaboury, Sayaboury Province, Laos, 12-II-1967 (BPBM); 1 pupal exuviae, as previous locality, 22-I-1967 (BPBM); 1 pupal exuviae, as previous locality, 23-VIII-1967 (BPBM); 1 pupal exuviae, Phu Khi Minh Mountain, Moung Sayaboury, Sayaboury Province, Laos, 8-I-1967 (BPBM); 1 pupal exuviae, Bindoon, Western Australia, Australia, 27-X-1985 (ANIC); 1 pupal exuviae, Weeli Woli Spring, Fortescue River, Pilbara, Western Australia, Australia, 17-X-1995 (ANIC); 1 pupal exuviae, Mooka Ruins, Gascoyne River, Western Australia, Australia (ANIC); 1 pupal exuviae, Gap Creek trib. Fitzroy River, Western Australia, Australia (ANIC); 1 pupal exuviae, Lady Carrington Drive, Royal National Park, New South Wales, Australia (ANIC); 1 pupal exuviae, McCarrs Creek, New South Wales, Australia, 14-I-1969 (ANIC).
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 61-63, DOI: 10.11646/zootaxa.3879.1.1, http://zenodo.org/record/4949051