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

description: Monohelea Kieffer
(Figs. 20I, 25F, 30C, 36F, 44P, 49F, 61B–C, 74H)
DIAGNOSIS: Only pupa of Ceratopogonidae with the mesonotum with at least one moderately elongate tubercle bearing some sensilla (Fig. 30C), with three ventral setae (V-5-IV, V-6-IV, V-7-IV) on very short tubercles (Figs. 61 B-C) and the respiratory organ with pores restricted to its apex (Fig. 44P).
DESCRIPTION: Total length = 2.09–2.38 mm. Without larval exuviae retained on abdomen. Exuviae with flagellum appressed against lateral margin of face, midleg, wing (as in Figs. 15D, 33B). Ecdysial tear posterior to base of antenna or just medial to base (as in Figs. 15D, 79D, E); along prothoracic extension. Head: Dorsal apotome (Fig. 20I), without ventral line of weakness, without dorsomedial tubercle, without central dome; dorsolateral cephalic sclerite (probably as in Fig. 13H) probably fused to scutum (inadequate material available), each side separated medially by dorsal apotome in whole pupa; mouthparts (Fig. 25F) with mandible welldeveloped, lacinia absent; palpus extending posterior to posterolateral margin of labium; labium separated medially by labrum, hypopharynx; apex of antenna (Fig. 36F) anterior to posterior extent of midlength portion of midleg (portion lateral to mesosternum), narrowed posteriorly; sensilla: dorsal apotomals (Fig. 20I)—1 short seta, 1 campaniform sensillum; dorsolateral cephalic sclerite sensilla—1 very short seta, 1 campaniform sensillum; clypeal-labrals (Fig. 25F)—1 slender seta; oculars (Fig. 25F)—1 seta, 2 campaniform sensilla. Thorax: Prothoracic extension (Fig. 25F) wide, well-developed but narrow dorsolaterally, extending from palpus to antenna; mesonotum with short to well-developed moderately sized tubercles, not extending posteromedially, with short protuberance, not dividing metathorax medially (Fig. 49F); respiratory organ (Fig. 44P) length/width = 3.71–4.22, moderately elongate, somewhat flattened dorsoventrally, with pores closely abutting at apex of respiratory organ, arranged in single row (but see taxonomic discussion), outer surface smooth, with moderately elongate, wide pedicel, base without posteromedial apodeme, membranous base of respiratory organ short, tracheal tube straight to slightly curved along length, with spirals restricted to basal third, distally smooth or with reticulations; wing (Fig. 36F) with angle lateral to apex of hind leg, separated medially by fore-, midlegs; halter apex and hind leg (as in Fig. 33A) broadly abutting; halter apex abutting anterolateral knob-like extension of tergite 2; legs (Fig. 36F) 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—absent (or perhaps very short among shagreen); anterolaterals—1 seta (shagreen making it difficult to interpret if more); dorsal setae (Fig. 30C)—D-1-T, D-2-T, D- 4-T very short setae, D-5-T either very short or a campaniform sensillum (difficult to discern difference), D-3-T campaniform sensillum; D-1-T, D-2-T, D-3-T, D-4-T on single well-developed tubercle; supraalar 2—campaniform sensillum; metathoracics (Fig. 49F)—1 very small seta, 1 campaniform sensillum; 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, peg-like or thin to thick setae, with rounded, very short to moderately elongate tubercles, tergites or sternites entire, each without membranous disc; segment 9 (Fig. 74H) not strongly modified, terminal processes closely approximated basally, each projecting posterodorsolaterally, tapering to pointed apex; sensilla: tergite 1 (Fig. 49F) with 6 setae, 2 campaniform sensilla, including 4 lateral sensilla, D-2-I, D-3-I closely approximated, D-7-I situated anterolaterally near L-1-I; segment 4 (Figs. 61 B-C)—D-2-IV peg-like seta, D-3-IV elongate seta, D-2-IV on short or elongate tubercle, D-3-IV on short tubercle; D-5-IV, D-8-IV peg-like setae, D-9-IV short seta, D-4-IV absent or not visible in M. hirsuta; on short or large separate tubercles, posterior dorsal sensilla in transverse row, arranged medially to laterally: D-5-IV, D-4-IV, D-8-IV, D-9-IV; D-7-IV near L-1-IV; L-1-IV short seta, on rounded or elongate tubercle with L-3-IV; L-2-IV, L-3- IV, L-4-IV short setae without tubercles (or very short) or well-developed tubercles, V-5-IV, V-6-IV, V-7-IV short setae, on rounded tubercles, V-6-IV, V-7-IV closely approximated; segment 8 without D-3-VIII, without L-1-VIII; segment 9 (Fig. 74H)—with D-5-IX, D-6-IX campaniform sensilla.
DISTRIBUTION AND HABITAT: The genus Monohelea is known from 88 species from every Region worldwide (Borkent 2014). Immatures have been reared from Sphagnum moss from lake margins and a swamp, or Sphagnum bogs.
TAXONOMIC DISCUSSION: There are only two species of Monohelea known as pupae (Tables 2–3). The species differ significantly in that M. hirsuta has well-developed tubercles on the abdomen (Fig. 61C), very similar to that of Allohelea japonica, while in M. obscura these are very short. The pupal exuviae of M. obscura was on a separate slide without an associated adult. It had been collected by H.A. Jamnback and was slide mounted by W.W. Wirth. Although likely correctly associated (Jamnback certainly had ample experience with rearing Ceratopogonidae), there remains a question of its identity.
The fourth abdominal segment of M. hirsuta (Fig. 61C) is illustrated without sensillum D-4-IV but this sensillum coeloconica (in other ceratopogonids) is likely present but hidden among the strong shagreen present over much of the abdomen of this species.
Harris (1981) also described the pupae of three species she identified as Monohelea (as sp. n. 1, sp. n. 2, sp. n. 3). Since then Wirth & Grogan (1988) recognized the status of six genera formerly placed in Monohelea, including four genera known from Australia: Monohelea, Allohelea, Austrohelea, and Downeshelea. The reared adults were never described but Harris (1981: 114) noted that " M. sp. n. 2 (a 'picture wing' species) is definitely different from M. sp. n. 1 and M. sp. n. 2 [sic] (plain wing species) at the pupal stage". Because of this obvious error, it is uncertain which species of these three are actually "picture wing" (i.e. possibly Monohelea, Downeshelea, or Allohelea) and which are most likely Austrohelea (plain wing) as far as adult features are concerned (one possible exception is Monohelea tigrina (Skuse), an Australian species with plain wings). However, named species of Austrohelea are known only from Western Australia and Tasmania, while the material of Harris (1981) came from Queensland. Additionally, her pupal key on pg. 92 identifies the three species but within that key Monohelea sp. n. 2 actually refers to M. sp. n. 1 in the text and figures and her keyed Monohelea sp. n. 1 actually refers to the texts and figures of M. sp. n. 2. In the current study, material from elsewhere was available for all these genera other than Downeshelea. Based on pupal features described by Harris (1981), all three would be members of Monohelea based on the presence of L-1-IV directly dorsal to L-3-IV, a feature unique to this genus within this group of genera (but based on only two species) in its exact relative placement of these two sensilla (see character 65). In addition all three have a peg-like D-5-T on the mesothorax, a feature here recognized here as a synapomorphy of Atyphohelea but not scorable with the material I examined of the closely related Monohelea because the presence of D-5-T was uncertain in the two species (and two specimens) available because of the small size of the sensilla amongst heavy shagreen, as well as poor perspective. However, Monohelea and related genera in the present scheme do not have a full complement of posterior dorsal sensilla illustrated as present in M. sp. n. 1 (D-4-IV, D-5- IV, D-7-IV, D-8-IV, D-9-IV) and the two species I examined have most sensilla on segment 4 as short pegs (in M. sp. n. 1 only V-5-IV was apparently peg-like), making the generic identification of M. sp. n. 1 uncertain. Both M. sp. n. 2 and M. sp. n. 3 would fit the diagnosis of Monohelea as presented here. However, all three species had at least one extra, separate subapical pore on the respiratory organ that is not present in the two species I examined. Further to this, if two of these three species did have clear wings (but were correctly identified at the time in the broadly encompassing concept of Monohelea), they could only belong to Austrohelea, a genus here considered more distantly related to Monohelea and without L-1-IV directly dorsal to L-3-IV for the one species I examined. Unfortunately, the location of the material described by Harris (1981) is uncertain and could not be reexamined (Marlene Elson-Harris, pers. comm. 1993).
The respiratory organ of M. hirsuta was drawn by Wirth & Grogan (1981) with an apparent longitudinal ridge or thickening but examination of the original material indicated that this was actually a flattened, possibly partially collapsed portion of the respiratory organ.
The pupae of Monohelea hirsuta, Allohelea, some Parabezzia and Atyphohelea are similar to one another, with pronounced tubercles on the thorax and abdomen. However, Monohelea have L-3-IV ventral to L-1-IV, while in Allohelea and Atyphohelea L-1-IV is further anterior than any of the other lateral sensilla. Parabezzia are missing L-1-IV.
MATERIAL EXAMINED: M. hirsuta: 1 pupal exuviae (of holotype), Patuxent Wildlife Refuge, Prince George County, Maryland, USA, 2-VIII-1977 (USNM). M. obscura: 1 pupal exuviae, Blue Mountain Lake, New York, USA, 10-VI-1958 (NYSM).
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 69-71, DOI: 10.11646/zootaxa.3879.1.1, http://zenodo.org/record/4949051